// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package reflect implements run-time reflection, allowing a program to
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// manipulate objects with arbitrary types. The typical use is to take a value
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// with static type interface{} and extract its dynamic type information by
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// calling TypeOf, which returns a Type.
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//
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// A call to ValueOf returns a Value representing the run-time data.
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// Zero takes a Type and returns a Value representing a zero value
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// for that type.
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//
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// See "The Laws of Reflection" for an introduction to reflection in Go:
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// https://golang.org/doc/articles/laws_of_reflection.html
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package reflect
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import (
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"runtime"
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"strconv"
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"sync"
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"unicode"
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"unicode/utf8"
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"unsafe"
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)
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// Type is the representation of a Go type.
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//
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// Not all methods apply to all kinds of types. Restrictions,
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// if any, are noted in the documentation for each method.
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// Use the Kind method to find out the kind of type before
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// calling kind-specific methods. Calling a method
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// inappropriate to the kind of type causes a run-time panic.
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//
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// Type values are comparable, such as with the == operator,
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// so they can be used as map keys.
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// Two Type values are equal if they represent identical types.
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type Type interface {
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// Methods applicable to all types.
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// Align returns the alignment in bytes of a value of
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// this type when allocated in memory.
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Align() int
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// FieldAlign returns the alignment in bytes of a value of
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// this type when used as a field in a struct.
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FieldAlign() int
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// Method returns the i'th method in the type's method set.
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// It panics if i is not in the range [0, NumMethod()).
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//
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// For a non-interface type T or *T, the returned Method's Type and Func
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// fields describe a function whose first argument is the receiver.
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//
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// For an interface type, the returned Method's Type field gives the
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// method signature, without a receiver, and the Func field is nil.
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Method(int) Method
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// MethodByName returns the method with that name in the type's
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// method set and a boolean indicating if the method was found.
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//
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// For a non-interface type T or *T, the returned Method's Type and Func
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// fields describe a function whose first argument is the receiver.
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//
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// For an interface type, the returned Method's Type field gives the
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// method signature, without a receiver, and the Func field is nil.
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MethodByName(string) (Method, bool)
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// NumMethod returns the number of exported methods in the type's method set.
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NumMethod() int
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// Name returns the type's name within its package for a defined type.
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// For other (non-defined) types it returns the empty string.
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Name() string
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// PkgPath returns a defined type's package path, that is, the import path
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// that uniquely identifies the package, such as "encoding/base64".
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// If the type was predeclared (string, error) or not defined (*T, struct{},
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// []int, or A where A is an alias for a non-defined type), the package path
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// will be the empty string.
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PkgPath() string
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// Size returns the number of bytes needed to store
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// a value of the given type; it is analogous to unsafe.Sizeof.
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Size() uintptr
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// String returns a string representation of the type.
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// The string representation may use shortened package names
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// (e.g., base64 instead of "encoding/base64") and is not
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// guaranteed to be unique among types. To test for type identity,
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// compare the Types directly.
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String() string
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// Kind returns the specific kind of this type.
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Kind() Kind
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// Implements reports whether the type implements the interface type u.
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Implements(u Type) bool
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// AssignableTo reports whether a value of the type is assignable to type u.
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AssignableTo(u Type) bool
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// ConvertibleTo reports whether a value of the type is convertible to type u.
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ConvertibleTo(u Type) bool
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// Comparable reports whether values of this type are comparable.
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Comparable() bool
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// Methods applicable only to some types, depending on Kind.
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// The methods allowed for each kind are:
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//
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// Int*, Uint*, Float*, Complex*: Bits
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// Array: Elem, Len
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// Chan: ChanDir, Elem
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// Func: In, NumIn, Out, NumOut, IsVariadic.
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// Map: Key, Elem
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// Ptr: Elem
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// Slice: Elem
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// Struct: Field, FieldByIndex, FieldByName, FieldByNameFunc, NumField
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// Bits returns the size of the type in bits.
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// It panics if the type's Kind is not one of the
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// sized or unsized Int, Uint, Float, or Complex kinds.
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Bits() int
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// ChanDir returns a channel type's direction.
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// It panics if the type's Kind is not Chan.
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ChanDir() ChanDir
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// IsVariadic reports whether a function type's final input parameter
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// is a "..." parameter. If so, t.In(t.NumIn() - 1) returns the parameter's
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// implicit actual type []T.
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//
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// For concreteness, if t represents func(x int, y ... float64), then
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//
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// t.NumIn() == 2
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// t.In(0) is the reflect.Type for "int"
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// t.In(1) is the reflect.Type for "[]float64"
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// t.IsVariadic() == true
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//
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// IsVariadic panics if the type's Kind is not Func.
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IsVariadic() bool
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// Elem returns a type's element type.
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// It panics if the type's Kind is not Array, Chan, Map, Ptr, or Slice.
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Elem() Type
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// Field returns a struct type's i'th field.
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// It panics if the type's Kind is not Struct.
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// It panics if i is not in the range [0, NumField()).
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Field(i int) StructField
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// FieldByIndex returns the nested field corresponding
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// to the index sequence. It is equivalent to calling Field
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// successively for each index i.
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// It panics if the type's Kind is not Struct.
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FieldByIndex(index []int) StructField
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// FieldByName returns the struct field with the given name
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// and a boolean indicating if the field was found.
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FieldByName(name string) (StructField, bool)
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// FieldByNameFunc returns the struct field with a name
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// that satisfies the match function and a boolean indicating if
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// the field was found.
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//
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// FieldByNameFunc considers the fields in the struct itself
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// and then the fields in any embedded structs, in breadth first order,
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// stopping at the shallowest nesting depth containing one or more
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// fields satisfying the match function. If multiple fields at that depth
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// satisfy the match function, they cancel each other
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// and FieldByNameFunc returns no match.
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// This behavior mirrors Go's handling of name lookup in
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// structs containing embedded fields.
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FieldByNameFunc(match func(string) bool) (StructField, bool)
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// In returns the type of a function type's i'th input parameter.
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// It panics if the type's Kind is not Func.
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// It panics if i is not in the range [0, NumIn()).
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In(i int) Type
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// Key returns a map type's key type.
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// It panics if the type's Kind is not Map.
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Key() Type
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// Len returns an array type's length.
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// It panics if the type's Kind is not Array.
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Len() int
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// NumField returns a struct type's field count.
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// It panics if the type's Kind is not Struct.
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NumField() int
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// NumIn returns a function type's input parameter count.
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// It panics if the type's Kind is not Func.
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NumIn() int
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// NumOut returns a function type's output parameter count.
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// It panics if the type's Kind is not Func.
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NumOut() int
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// Out returns the type of a function type's i'th output parameter.
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// It panics if the type's Kind is not Func.
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// It panics if i is not in the range [0, NumOut()).
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Out(i int) Type
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common() *rtype
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uncommon() *uncommonType
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}
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// BUG(rsc): FieldByName and related functions consider struct field names to be equal
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// if the names are equal, even if they are unexported names originating
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// in different packages. The practical effect of this is that the result of
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// t.FieldByName("x") is not well defined if the struct type t contains
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// multiple fields named x (embedded from different packages).
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// FieldByName may return one of the fields named x or may report that there are none.
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// See https://golang.org/issue/4876 for more details.
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/*
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* These data structures are known to the compiler (../../cmd/internal/gc/reflect.go).
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* A few are known to ../runtime/type.go to convey to debuggers.
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* They are also known to ../runtime/type.go.
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*/
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// A Kind represents the specific kind of type that a Type represents.
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// The zero Kind is not a valid kind.
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type Kind uint
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const (
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Invalid Kind = iota
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Bool
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Int
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Int8
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Int16
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Int32
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Int64
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Uint
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Uint8
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Uint16
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Uint32
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Uint64
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Uintptr
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Float32
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Float64
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Complex64
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Complex128
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Array
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Chan
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Func
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Interface
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Map
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Ptr
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Slice
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String
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Struct
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UnsafePointer
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)
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// tflag is used by an rtype to signal what extra type information is
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// available in the memory directly following the rtype value.
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//
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// tflag values must be kept in sync with copies in:
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// cmd/compile/internal/gc/reflect.go
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// cmd/link/internal/ld/decodesym.go
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// runtime/type.go
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type tflag uint8
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const (
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// tflagUncommon means that there is a pointer, *uncommonType,
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// just beyond the outer type structure.
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//
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// For example, if t.Kind() == Struct and t.tflag&tflagUncommon != 0,
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// then t has uncommonType data and it can be accessed as:
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//
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// type tUncommon struct {
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// structType
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// u uncommonType
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// }
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// u := &(*tUncommon)(unsafe.Pointer(t)).u
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tflagUncommon tflag = 1 << 0
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// tflagExtraStar means the name in the str field has an
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// extraneous '*' prefix. This is because for most types T in
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// a program, the type *T also exists and reusing the str data
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// saves binary size.
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tflagExtraStar tflag = 1 << 1
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// tflagNamed means the type has a name.
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tflagNamed tflag = 1 << 2
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)
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// rtype is the common implementation of most values.
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// It is embedded in other struct types.
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//
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// rtype must be kept in sync with ../runtime/type.go:/^type._type.
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type rtype struct {
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size uintptr
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ptrdata uintptr // number of bytes in the type that can contain pointers
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hash uint32 // hash of type; avoids computation in hash tables
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tflag tflag // extra type information flags
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align uint8 // alignment of variable with this type
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fieldAlign uint8 // alignment of struct field with this type
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kind uint8 // enumeration for C
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alg *typeAlg // algorithm table
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gcdata *byte // garbage collection data
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str nameOff // string form
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ptrToThis typeOff // type for pointer to this type, may be zero
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}
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// a copy of runtime.typeAlg
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type typeAlg struct {
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// function for hashing objects of this type
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// (ptr to object, seed) -> hash
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hash func(unsafe.Pointer, uintptr) uintptr
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// function for comparing objects of this type
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// (ptr to object A, ptr to object B) -> ==?
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equal func(unsafe.Pointer, unsafe.Pointer) bool
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}
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// Method on non-interface type
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type method struct {
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name nameOff // name of method
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mtyp typeOff // method type (without receiver)
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ifn textOff // fn used in interface call (one-word receiver)
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tfn textOff // fn used for normal method call
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}
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// uncommonType is present only for defined types or types with methods
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// (if T is a defined type, the uncommonTypes for T and *T have methods).
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// Using a pointer to this struct reduces the overall size required
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// to describe a non-defined type with no methods.
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type uncommonType struct {
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pkgPath nameOff // import path; empty for built-in types like int, string
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mcount uint16 // number of methods
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xcount uint16 // number of exported methods
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moff uint32 // offset from this uncommontype to [mcount]method
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_ uint32 // unused
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}
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// ChanDir represents a channel type's direction.
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type ChanDir int
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const (
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RecvDir ChanDir = 1 << iota // <-chan
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SendDir // chan<-
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BothDir = RecvDir | SendDir // chan
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)
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// arrayType represents a fixed array type.
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type arrayType struct {
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rtype
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elem *rtype // array element type
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slice *rtype // slice type
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len uintptr
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}
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// chanType represents a channel type.
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type chanType struct {
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rtype
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elem *rtype // channel element type
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dir uintptr // channel direction (ChanDir)
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}
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// funcType represents a function type.
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//
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// A *rtype for each in and out parameter is stored in an array that
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// directly follows the funcType (and possibly its uncommonType). So
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// a function type with one method, one input, and one output is:
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//
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// struct {
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// funcType
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// uncommonType
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// [2]*rtype // [0] is in, [1] is out
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// }
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type funcType struct {
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rtype
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inCount uint16
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outCount uint16 // top bit is set if last input parameter is ...
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}
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// imethod represents a method on an interface type
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type imethod struct {
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name nameOff // name of method
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typ typeOff // .(*FuncType) underneath
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}
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// interfaceType represents an interface type.
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type interfaceType struct {
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rtype
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pkgPath name // import path
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methods []imethod // sorted by hash
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}
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// mapType represents a map type.
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type mapType struct {
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rtype
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key *rtype // map key type
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elem *rtype // map element (value) type
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bucket *rtype // internal bucket structure
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keysize uint8 // size of key slot
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valuesize uint8 // size of value slot
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bucketsize uint16 // size of bucket
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flags uint32
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}
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// ptrType represents a pointer type.
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type ptrType struct {
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rtype
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elem *rtype // pointer element (pointed at) type
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}
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// sliceType represents a slice type.
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type sliceType struct {
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rtype
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elem *rtype // slice element type
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}
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// Struct field
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type structField struct {
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name name // name is always non-empty
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typ *rtype // type of field
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offsetEmbed uintptr // byte offset of field<<1 | isEmbedded
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}
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func (f *structField) offset() uintptr {
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return f.offsetEmbed >> 1
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}
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func (f *structField) embedded() bool {
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return f.offsetEmbed&1 != 0
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}
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// structType represents a struct type.
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type structType struct {
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rtype
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pkgPath name
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fields []structField // sorted by offset
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}
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// name is an encoded type name with optional extra data.
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//
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// The first byte is a bit field containing:
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//
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// 1<<0 the name is exported
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// 1<<1 tag data follows the name
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// 1<<2 pkgPath nameOff follows the name and tag
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//
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// The next two bytes are the data length:
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//
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// l := uint16(data[1])<<8 | uint16(data[2])
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//
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// Bytes [3:3+l] are the string data.
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//
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// If tag data follows then bytes 3+l and 3+l+1 are the tag length,
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// with the data following.
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//
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// If the import path follows, then 4 bytes at the end of
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// the data form a nameOff. The import path is only set for concrete
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// methods that are defined in a different package than their type.
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//
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// If a name starts with "*", then the exported bit represents
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// whether the pointed to type is exported.
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type name struct {
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bytes *byte
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}
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func (n name) data(off int, whySafe string) *byte {
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return (*byte)(add(unsafe.Pointer(n.bytes), uintptr(off), whySafe))
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}
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func (n name) isExported() bool {
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return (*n.bytes)&(1<<0) != 0
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}
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func (n name) nameLen() int {
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return int(uint16(*n.data(1, "name len field"))<<8 | uint16(*n.data(2, "name len field")))
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}
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func (n name) tagLen() int {
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if *n.data(0, "name flag field")&(1<<1) == 0 {
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return 0
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}
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off := 3 + n.nameLen()
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return int(uint16(*n.data(off, "name taglen field"))<<8 | uint16(*n.data(off+1, "name taglen field")))
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}
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func (n name) name() (s string) {
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if n.bytes == nil {
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return
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}
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b := (*[4]byte)(unsafe.Pointer(n.bytes))
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hdr := (*stringHeader)(unsafe.Pointer(&s))
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hdr.Data = unsafe.Pointer(&b[3])
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hdr.Len = int(b[1])<<8 | int(b[2])
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return s
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}
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func (n name) tag() (s string) {
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tl := n.tagLen()
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if tl == 0 {
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return ""
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}
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nl := n.nameLen()
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hdr := (*stringHeader)(unsafe.Pointer(&s))
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hdr.Data = unsafe.Pointer(n.data(3+nl+2, "non-empty string"))
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hdr.Len = tl
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return s
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}
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func (n name) pkgPath() string {
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if n.bytes == nil || *n.data(0, "name flag field")&(1<<2) == 0 {
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return ""
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}
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off := 3 + n.nameLen()
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if tl := n.tagLen(); tl > 0 {
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off += 2 + tl
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}
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var nameOff int32
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// Note that this field may not be aligned in memory,
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// so we cannot use a direct int32 assignment here.
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copy((*[4]byte)(unsafe.Pointer(&nameOff))[:], (*[4]byte)(unsafe.Pointer(n.data(off, "name offset field")))[:])
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pkgPathName := name{(*byte)(resolveTypeOff(unsafe.Pointer(n.bytes), nameOff))}
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return pkgPathName.name()
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}
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// round n up to a multiple of a. a must be a power of 2.
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func round(n, a uintptr) uintptr {
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return (n + a - 1) &^ (a - 1)
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}
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func newName(n, tag string, exported bool) name {
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if len(n) > 1<<16-1 {
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panic("reflect.nameFrom: name too long: " + n)
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}
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if len(tag) > 1<<16-1 {
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panic("reflect.nameFrom: tag too long: " + tag)
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}
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var bits byte
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l := 1 + 2 + len(n)
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if exported {
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bits |= 1 << 0
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}
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if len(tag) > 0 {
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l += 2 + len(tag)
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bits |= 1 << 1
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}
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b := make([]byte, l)
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b[0] = bits
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b[1] = uint8(len(n) >> 8)
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b[2] = uint8(len(n))
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copy(b[3:], n)
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if len(tag) > 0 {
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tb := b[3+len(n):]
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tb[0] = uint8(len(tag) >> 8)
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tb[1] = uint8(len(tag))
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copy(tb[2:], tag)
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}
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return name{bytes: &b[0]}
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}
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/*
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* The compiler knows the exact layout of all the data structures above.
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* The compiler does not know about the data structures and methods below.
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*/
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// Method represents a single method.
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type Method struct {
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// Name is the method name.
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// PkgPath is the package path that qualifies a lower case (unexported)
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// method name. It is empty for upper case (exported) method names.
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// The combination of PkgPath and Name uniquely identifies a method
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// in a method set.
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// See https://golang.org/ref/spec#Uniqueness_of_identifiers
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Name string
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PkgPath string
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Type Type // method type
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Func Value // func with receiver as first argument
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Index int // index for Type.Method
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}
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const (
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kindDirectIface = 1 << 5
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kindGCProg = 1 << 6 // Type.gc points to GC program
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kindNoPointers = 1 << 7
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kindMask = (1 << 5) - 1
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)
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// String returns the name of k.
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func (k Kind) String() string {
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if int(k) < len(kindNames) {
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return kindNames[k]
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}
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return "kind" + strconv.Itoa(int(k))
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}
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var kindNames = []string{
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Invalid: "invalid",
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Bool: "bool",
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Int: "int",
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Int8: "int8",
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Int16: "int16",
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Int32: "int32",
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Int64: "int64",
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Uint: "uint",
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Uint8: "uint8",
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Uint16: "uint16",
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Uint32: "uint32",
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Uint64: "uint64",
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Uintptr: "uintptr",
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Float32: "float32",
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Float64: "float64",
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Complex64: "complex64",
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Complex128: "complex128",
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Array: "array",
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Chan: "chan",
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Func: "func",
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Interface: "interface",
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Map: "map",
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Ptr: "ptr",
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Slice: "slice",
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String: "string",
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Struct: "struct",
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UnsafePointer: "unsafe.Pointer",
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}
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func (t *uncommonType) methods() []method {
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if t.mcount == 0 {
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return nil
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}
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return (*[1 << 16]method)(add(unsafe.Pointer(t), uintptr(t.moff), "t.mcount > 0"))[:t.mcount:t.mcount]
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}
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func (t *uncommonType) exportedMethods() []method {
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if t.xcount == 0 {
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return nil
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}
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return (*[1 << 16]method)(add(unsafe.Pointer(t), uintptr(t.moff), "t.xcount > 0"))[:t.xcount:t.xcount]
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}
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// resolveNameOff resolves a name offset from a base pointer.
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// The (*rtype).nameOff method is a convenience wrapper for this function.
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// Implemented in the runtime package.
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func resolveNameOff(ptrInModule unsafe.Pointer, off int32) unsafe.Pointer
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// resolveTypeOff resolves an *rtype offset from a base type.
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// The (*rtype).typeOff method is a convenience wrapper for this function.
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// Implemented in the runtime package.
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func resolveTypeOff(rtype unsafe.Pointer, off int32) unsafe.Pointer
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// resolveTextOff resolves an function pointer offset from a base type.
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// The (*rtype).textOff method is a convenience wrapper for this function.
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// Implemented in the runtime package.
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func resolveTextOff(rtype unsafe.Pointer, off int32) unsafe.Pointer
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// addReflectOff adds a pointer to the reflection lookup map in the runtime.
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// It returns a new ID that can be used as a typeOff or textOff, and will
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// be resolved correctly. Implemented in the runtime package.
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func addReflectOff(ptr unsafe.Pointer) int32
|
|
// resolveReflectType adds a name to the reflection lookup map in the runtime.
|
// It returns a new nameOff that can be used to refer to the pointer.
|
func resolveReflectName(n name) nameOff {
|
return nameOff(addReflectOff(unsafe.Pointer(n.bytes)))
|
}
|
|
// resolveReflectType adds a *rtype to the reflection lookup map in the runtime.
|
// It returns a new typeOff that can be used to refer to the pointer.
|
func resolveReflectType(t *rtype) typeOff {
|
return typeOff(addReflectOff(unsafe.Pointer(t)))
|
}
|
|
// resolveReflectText adds a function pointer to the reflection lookup map in
|
// the runtime. It returns a new textOff that can be used to refer to the
|
// pointer.
|
func resolveReflectText(ptr unsafe.Pointer) textOff {
|
return textOff(addReflectOff(ptr))
|
}
|
|
type nameOff int32 // offset to a name
|
type typeOff int32 // offset to an *rtype
|
type textOff int32 // offset from top of text section
|
|
func (t *rtype) nameOff(off nameOff) name {
|
return name{(*byte)(resolveNameOff(unsafe.Pointer(t), int32(off)))}
|
}
|
|
func (t *rtype) typeOff(off typeOff) *rtype {
|
return (*rtype)(resolveTypeOff(unsafe.Pointer(t), int32(off)))
|
}
|
|
func (t *rtype) textOff(off textOff) unsafe.Pointer {
|
return resolveTextOff(unsafe.Pointer(t), int32(off))
|
}
|
|
func (t *rtype) uncommon() *uncommonType {
|
if t.tflag&tflagUncommon == 0 {
|
return nil
|
}
|
switch t.Kind() {
|
case Struct:
|
return &(*structTypeUncommon)(unsafe.Pointer(t)).u
|
case Ptr:
|
type u struct {
|
ptrType
|
u uncommonType
|
}
|
return &(*u)(unsafe.Pointer(t)).u
|
case Func:
|
type u struct {
|
funcType
|
u uncommonType
|
}
|
return &(*u)(unsafe.Pointer(t)).u
|
case Slice:
|
type u struct {
|
sliceType
|
u uncommonType
|
}
|
return &(*u)(unsafe.Pointer(t)).u
|
case Array:
|
type u struct {
|
arrayType
|
u uncommonType
|
}
|
return &(*u)(unsafe.Pointer(t)).u
|
case Chan:
|
type u struct {
|
chanType
|
u uncommonType
|
}
|
return &(*u)(unsafe.Pointer(t)).u
|
case Map:
|
type u struct {
|
mapType
|
u uncommonType
|
}
|
return &(*u)(unsafe.Pointer(t)).u
|
case Interface:
|
type u struct {
|
interfaceType
|
u uncommonType
|
}
|
return &(*u)(unsafe.Pointer(t)).u
|
default:
|
type u struct {
|
rtype
|
u uncommonType
|
}
|
return &(*u)(unsafe.Pointer(t)).u
|
}
|
}
|
|
func (t *rtype) String() string {
|
s := t.nameOff(t.str).name()
|
if t.tflag&tflagExtraStar != 0 {
|
return s[1:]
|
}
|
return s
|
}
|
|
func (t *rtype) Size() uintptr { return t.size }
|
|
func (t *rtype) Bits() int {
|
if t == nil {
|
panic("reflect: Bits of nil Type")
|
}
|
k := t.Kind()
|
if k < Int || k > Complex128 {
|
panic("reflect: Bits of non-arithmetic Type " + t.String())
|
}
|
return int(t.size) * 8
|
}
|
|
func (t *rtype) Align() int { return int(t.align) }
|
|
func (t *rtype) FieldAlign() int { return int(t.fieldAlign) }
|
|
func (t *rtype) Kind() Kind { return Kind(t.kind & kindMask) }
|
|
func (t *rtype) pointers() bool { return t.kind&kindNoPointers == 0 }
|
|
func (t *rtype) common() *rtype { return t }
|
|
func (t *rtype) exportedMethods() []method {
|
ut := t.uncommon()
|
if ut == nil {
|
return nil
|
}
|
return ut.exportedMethods()
|
}
|
|
func (t *rtype) NumMethod() int {
|
if t.Kind() == Interface {
|
tt := (*interfaceType)(unsafe.Pointer(t))
|
return tt.NumMethod()
|
}
|
return len(t.exportedMethods())
|
}
|
|
func (t *rtype) Method(i int) (m Method) {
|
if t.Kind() == Interface {
|
tt := (*interfaceType)(unsafe.Pointer(t))
|
return tt.Method(i)
|
}
|
methods := t.exportedMethods()
|
if i < 0 || i >= len(methods) {
|
panic("reflect: Method index out of range")
|
}
|
p := methods[i]
|
pname := t.nameOff(p.name)
|
m.Name = pname.name()
|
fl := flag(Func)
|
mtyp := t.typeOff(p.mtyp)
|
ft := (*funcType)(unsafe.Pointer(mtyp))
|
in := make([]Type, 0, 1+len(ft.in()))
|
in = append(in, t)
|
for _, arg := range ft.in() {
|
in = append(in, arg)
|
}
|
out := make([]Type, 0, len(ft.out()))
|
for _, ret := range ft.out() {
|
out = append(out, ret)
|
}
|
mt := FuncOf(in, out, ft.IsVariadic())
|
m.Type = mt
|
tfn := t.textOff(p.tfn)
|
fn := unsafe.Pointer(&tfn)
|
m.Func = Value{mt.(*rtype), fn, fl}
|
|
m.Index = i
|
return m
|
}
|
|
func (t *rtype) MethodByName(name string) (m Method, ok bool) {
|
if t.Kind() == Interface {
|
tt := (*interfaceType)(unsafe.Pointer(t))
|
return tt.MethodByName(name)
|
}
|
ut := t.uncommon()
|
if ut == nil {
|
return Method{}, false
|
}
|
// TODO(mdempsky): Binary search.
|
for i, p := range ut.exportedMethods() {
|
if t.nameOff(p.name).name() == name {
|
return t.Method(i), true
|
}
|
}
|
return Method{}, false
|
}
|
|
func (t *rtype) PkgPath() string {
|
if t.tflag&tflagNamed == 0 {
|
return ""
|
}
|
ut := t.uncommon()
|
if ut == nil {
|
return ""
|
}
|
return t.nameOff(ut.pkgPath).name()
|
}
|
|
func hasPrefix(s, prefix string) bool {
|
return len(s) >= len(prefix) && s[:len(prefix)] == prefix
|
}
|
|
func (t *rtype) Name() string {
|
if t.tflag&tflagNamed == 0 {
|
return ""
|
}
|
s := t.String()
|
i := len(s) - 1
|
for i >= 0 {
|
if s[i] == '.' {
|
break
|
}
|
i--
|
}
|
return s[i+1:]
|
}
|
|
func (t *rtype) ChanDir() ChanDir {
|
if t.Kind() != Chan {
|
panic("reflect: ChanDir of non-chan type")
|
}
|
tt := (*chanType)(unsafe.Pointer(t))
|
return ChanDir(tt.dir)
|
}
|
|
func (t *rtype) IsVariadic() bool {
|
if t.Kind() != Func {
|
panic("reflect: IsVariadic of non-func type")
|
}
|
tt := (*funcType)(unsafe.Pointer(t))
|
return tt.outCount&(1<<15) != 0
|
}
|
|
func (t *rtype) Elem() Type {
|
switch t.Kind() {
|
case Array:
|
tt := (*arrayType)(unsafe.Pointer(t))
|
return toType(tt.elem)
|
case Chan:
|
tt := (*chanType)(unsafe.Pointer(t))
|
return toType(tt.elem)
|
case Map:
|
tt := (*mapType)(unsafe.Pointer(t))
|
return toType(tt.elem)
|
case Ptr:
|
tt := (*ptrType)(unsafe.Pointer(t))
|
return toType(tt.elem)
|
case Slice:
|
tt := (*sliceType)(unsafe.Pointer(t))
|
return toType(tt.elem)
|
}
|
panic("reflect: Elem of invalid type")
|
}
|
|
func (t *rtype) Field(i int) StructField {
|
if t.Kind() != Struct {
|
panic("reflect: Field of non-struct type")
|
}
|
tt := (*structType)(unsafe.Pointer(t))
|
return tt.Field(i)
|
}
|
|
func (t *rtype) FieldByIndex(index []int) StructField {
|
if t.Kind() != Struct {
|
panic("reflect: FieldByIndex of non-struct type")
|
}
|
tt := (*structType)(unsafe.Pointer(t))
|
return tt.FieldByIndex(index)
|
}
|
|
func (t *rtype) FieldByName(name string) (StructField, bool) {
|
if t.Kind() != Struct {
|
panic("reflect: FieldByName of non-struct type")
|
}
|
tt := (*structType)(unsafe.Pointer(t))
|
return tt.FieldByName(name)
|
}
|
|
func (t *rtype) FieldByNameFunc(match func(string) bool) (StructField, bool) {
|
if t.Kind() != Struct {
|
panic("reflect: FieldByNameFunc of non-struct type")
|
}
|
tt := (*structType)(unsafe.Pointer(t))
|
return tt.FieldByNameFunc(match)
|
}
|
|
func (t *rtype) In(i int) Type {
|
if t.Kind() != Func {
|
panic("reflect: In of non-func type")
|
}
|
tt := (*funcType)(unsafe.Pointer(t))
|
return toType(tt.in()[i])
|
}
|
|
func (t *rtype) Key() Type {
|
if t.Kind() != Map {
|
panic("reflect: Key of non-map type")
|
}
|
tt := (*mapType)(unsafe.Pointer(t))
|
return toType(tt.key)
|
}
|
|
func (t *rtype) Len() int {
|
if t.Kind() != Array {
|
panic("reflect: Len of non-array type")
|
}
|
tt := (*arrayType)(unsafe.Pointer(t))
|
return int(tt.len)
|
}
|
|
func (t *rtype) NumField() int {
|
if t.Kind() != Struct {
|
panic("reflect: NumField of non-struct type")
|
}
|
tt := (*structType)(unsafe.Pointer(t))
|
return len(tt.fields)
|
}
|
|
func (t *rtype) NumIn() int {
|
if t.Kind() != Func {
|
panic("reflect: NumIn of non-func type")
|
}
|
tt := (*funcType)(unsafe.Pointer(t))
|
return int(tt.inCount)
|
}
|
|
func (t *rtype) NumOut() int {
|
if t.Kind() != Func {
|
panic("reflect: NumOut of non-func type")
|
}
|
tt := (*funcType)(unsafe.Pointer(t))
|
return len(tt.out())
|
}
|
|
func (t *rtype) Out(i int) Type {
|
if t.Kind() != Func {
|
panic("reflect: Out of non-func type")
|
}
|
tt := (*funcType)(unsafe.Pointer(t))
|
return toType(tt.out()[i])
|
}
|
|
func (t *funcType) in() []*rtype {
|
uadd := unsafe.Sizeof(*t)
|
if t.tflag&tflagUncommon != 0 {
|
uadd += unsafe.Sizeof(uncommonType{})
|
}
|
if t.inCount == 0 {
|
return nil
|
}
|
return (*[1 << 20]*rtype)(add(unsafe.Pointer(t), uadd, "t.inCount > 0"))[:t.inCount]
|
}
|
|
func (t *funcType) out() []*rtype {
|
uadd := unsafe.Sizeof(*t)
|
if t.tflag&tflagUncommon != 0 {
|
uadd += unsafe.Sizeof(uncommonType{})
|
}
|
outCount := t.outCount & (1<<15 - 1)
|
if outCount == 0 {
|
return nil
|
}
|
return (*[1 << 20]*rtype)(add(unsafe.Pointer(t), uadd, "outCount > 0"))[t.inCount : t.inCount+outCount]
|
}
|
|
// add returns p+x.
|
//
|
// The whySafe string is ignored, so that the function still inlines
|
// as efficiently as p+x, but all call sites should use the string to
|
// record why the addition is safe, which is to say why the addition
|
// does not cause x to advance to the very end of p's allocation
|
// and therefore point incorrectly at the next block in memory.
|
func add(p unsafe.Pointer, x uintptr, whySafe string) unsafe.Pointer {
|
return unsafe.Pointer(uintptr(p) + x)
|
}
|
|
func (d ChanDir) String() string {
|
switch d {
|
case SendDir:
|
return "chan<-"
|
case RecvDir:
|
return "<-chan"
|
case BothDir:
|
return "chan"
|
}
|
return "ChanDir" + strconv.Itoa(int(d))
|
}
|
|
// Method returns the i'th method in the type's method set.
|
func (t *interfaceType) Method(i int) (m Method) {
|
if i < 0 || i >= len(t.methods) {
|
return
|
}
|
p := &t.methods[i]
|
pname := t.nameOff(p.name)
|
m.Name = pname.name()
|
if !pname.isExported() {
|
m.PkgPath = pname.pkgPath()
|
if m.PkgPath == "" {
|
m.PkgPath = t.pkgPath.name()
|
}
|
}
|
m.Type = toType(t.typeOff(p.typ))
|
m.Index = i
|
return
|
}
|
|
// NumMethod returns the number of interface methods in the type's method set.
|
func (t *interfaceType) NumMethod() int { return len(t.methods) }
|
|
// MethodByName method with the given name in the type's method set.
|
func (t *interfaceType) MethodByName(name string) (m Method, ok bool) {
|
if t == nil {
|
return
|
}
|
var p *imethod
|
for i := range t.methods {
|
p = &t.methods[i]
|
if t.nameOff(p.name).name() == name {
|
return t.Method(i), true
|
}
|
}
|
return
|
}
|
|
// A StructField describes a single field in a struct.
|
type StructField struct {
|
// Name is the field name.
|
Name string
|
// PkgPath is the package path that qualifies a lower case (unexported)
|
// field name. It is empty for upper case (exported) field names.
|
// See https://golang.org/ref/spec#Uniqueness_of_identifiers
|
PkgPath string
|
|
Type Type // field type
|
Tag StructTag // field tag string
|
Offset uintptr // offset within struct, in bytes
|
Index []int // index sequence for Type.FieldByIndex
|
Anonymous bool // is an embedded field
|
}
|
|
// A StructTag is the tag string in a struct field.
|
//
|
// By convention, tag strings are a concatenation of
|
// optionally space-separated key:"value" pairs.
|
// Each key is a non-empty string consisting of non-control
|
// characters other than space (U+0020 ' '), quote (U+0022 '"'),
|
// and colon (U+003A ':'). Each value is quoted using U+0022 '"'
|
// characters and Go string literal syntax.
|
type StructTag string
|
|
// Get returns the value associated with key in the tag string.
|
// If there is no such key in the tag, Get returns the empty string.
|
// If the tag does not have the conventional format, the value
|
// returned by Get is unspecified. To determine whether a tag is
|
// explicitly set to the empty string, use Lookup.
|
func (tag StructTag) Get(key string) string {
|
v, _ := tag.Lookup(key)
|
return v
|
}
|
|
// Lookup returns the value associated with key in the tag string.
|
// If the key is present in the tag the value (which may be empty)
|
// is returned. Otherwise the returned value will be the empty string.
|
// The ok return value reports whether the value was explicitly set in
|
// the tag string. If the tag does not have the conventional format,
|
// the value returned by Lookup is unspecified.
|
func (tag StructTag) Lookup(key string) (value string, ok bool) {
|
// When modifying this code, also update the validateStructTag code
|
// in cmd/vet/structtag.go.
|
|
for tag != "" {
|
// Skip leading space.
|
i := 0
|
for i < len(tag) && tag[i] == ' ' {
|
i++
|
}
|
tag = tag[i:]
|
if tag == "" {
|
break
|
}
|
|
// Scan to colon. A space, a quote or a control character is a syntax error.
|
// Strictly speaking, control chars include the range [0x7f, 0x9f], not just
|
// [0x00, 0x1f], but in practice, we ignore the multi-byte control characters
|
// as it is simpler to inspect the tag's bytes than the tag's runes.
|
i = 0
|
for i < len(tag) && tag[i] > ' ' && tag[i] != ':' && tag[i] != '"' && tag[i] != 0x7f {
|
i++
|
}
|
if i == 0 || i+1 >= len(tag) || tag[i] != ':' || tag[i+1] != '"' {
|
break
|
}
|
name := string(tag[:i])
|
tag = tag[i+1:]
|
|
// Scan quoted string to find value.
|
i = 1
|
for i < len(tag) && tag[i] != '"' {
|
if tag[i] == '\\' {
|
i++
|
}
|
i++
|
}
|
if i >= len(tag) {
|
break
|
}
|
qvalue := string(tag[:i+1])
|
tag = tag[i+1:]
|
|
if key == name {
|
value, err := strconv.Unquote(qvalue)
|
if err != nil {
|
break
|
}
|
return value, true
|
}
|
}
|
return "", false
|
}
|
|
// Field returns the i'th struct field.
|
func (t *structType) Field(i int) (f StructField) {
|
if i < 0 || i >= len(t.fields) {
|
panic("reflect: Field index out of bounds")
|
}
|
p := &t.fields[i]
|
f.Type = toType(p.typ)
|
f.Name = p.name.name()
|
f.Anonymous = p.embedded()
|
if !p.name.isExported() {
|
f.PkgPath = t.pkgPath.name()
|
}
|
if tag := p.name.tag(); tag != "" {
|
f.Tag = StructTag(tag)
|
}
|
f.Offset = p.offset()
|
|
// NOTE(rsc): This is the only allocation in the interface
|
// presented by a reflect.Type. It would be nice to avoid,
|
// at least in the common cases, but we need to make sure
|
// that misbehaving clients of reflect cannot affect other
|
// uses of reflect. One possibility is CL 5371098, but we
|
// postponed that ugliness until there is a demonstrated
|
// need for the performance. This is issue 2320.
|
f.Index = []int{i}
|
return
|
}
|
|
// TODO(gri): Should there be an error/bool indicator if the index
|
// is wrong for FieldByIndex?
|
|
// FieldByIndex returns the nested field corresponding to index.
|
func (t *structType) FieldByIndex(index []int) (f StructField) {
|
f.Type = toType(&t.rtype)
|
for i, x := range index {
|
if i > 0 {
|
ft := f.Type
|
if ft.Kind() == Ptr && ft.Elem().Kind() == Struct {
|
ft = ft.Elem()
|
}
|
f.Type = ft
|
}
|
f = f.Type.Field(x)
|
}
|
return
|
}
|
|
// A fieldScan represents an item on the fieldByNameFunc scan work list.
|
type fieldScan struct {
|
typ *structType
|
index []int
|
}
|
|
// FieldByNameFunc returns the struct field with a name that satisfies the
|
// match function and a boolean to indicate if the field was found.
|
func (t *structType) FieldByNameFunc(match func(string) bool) (result StructField, ok bool) {
|
// This uses the same condition that the Go language does: there must be a unique instance
|
// of the match at a given depth level. If there are multiple instances of a match at the
|
// same depth, they annihilate each other and inhibit any possible match at a lower level.
|
// The algorithm is breadth first search, one depth level at a time.
|
|
// The current and next slices are work queues:
|
// current lists the fields to visit on this depth level,
|
// and next lists the fields on the next lower level.
|
current := []fieldScan{}
|
next := []fieldScan{{typ: t}}
|
|
// nextCount records the number of times an embedded type has been
|
// encountered and considered for queueing in the 'next' slice.
|
// We only queue the first one, but we increment the count on each.
|
// If a struct type T can be reached more than once at a given depth level,
|
// then it annihilates itself and need not be considered at all when we
|
// process that next depth level.
|
var nextCount map[*structType]int
|
|
// visited records the structs that have been considered already.
|
// Embedded pointer fields can create cycles in the graph of
|
// reachable embedded types; visited avoids following those cycles.
|
// It also avoids duplicated effort: if we didn't find the field in an
|
// embedded type T at level 2, we won't find it in one at level 4 either.
|
visited := map[*structType]bool{}
|
|
for len(next) > 0 {
|
current, next = next, current[:0]
|
count := nextCount
|
nextCount = nil
|
|
// Process all the fields at this depth, now listed in 'current'.
|
// The loop queues embedded fields found in 'next', for processing during the next
|
// iteration. The multiplicity of the 'current' field counts is recorded
|
// in 'count'; the multiplicity of the 'next' field counts is recorded in 'nextCount'.
|
for _, scan := range current {
|
t := scan.typ
|
if visited[t] {
|
// We've looked through this type before, at a higher level.
|
// That higher level would shadow the lower level we're now at,
|
// so this one can't be useful to us. Ignore it.
|
continue
|
}
|
visited[t] = true
|
for i := range t.fields {
|
f := &t.fields[i]
|
// Find name and (for embedded field) type for field f.
|
fname := f.name.name()
|
var ntyp *rtype
|
if f.embedded() {
|
// Embedded field of type T or *T.
|
ntyp = f.typ
|
if ntyp.Kind() == Ptr {
|
ntyp = ntyp.Elem().common()
|
}
|
}
|
|
// Does it match?
|
if match(fname) {
|
// Potential match
|
if count[t] > 1 || ok {
|
// Name appeared multiple times at this level: annihilate.
|
return StructField{}, false
|
}
|
result = t.Field(i)
|
result.Index = nil
|
result.Index = append(result.Index, scan.index...)
|
result.Index = append(result.Index, i)
|
ok = true
|
continue
|
}
|
|
// Queue embedded struct fields for processing with next level,
|
// but only if we haven't seen a match yet at this level and only
|
// if the embedded types haven't already been queued.
|
if ok || ntyp == nil || ntyp.Kind() != Struct {
|
continue
|
}
|
styp := (*structType)(unsafe.Pointer(ntyp))
|
if nextCount[styp] > 0 {
|
nextCount[styp] = 2 // exact multiple doesn't matter
|
continue
|
}
|
if nextCount == nil {
|
nextCount = map[*structType]int{}
|
}
|
nextCount[styp] = 1
|
if count[t] > 1 {
|
nextCount[styp] = 2 // exact multiple doesn't matter
|
}
|
var index []int
|
index = append(index, scan.index...)
|
index = append(index, i)
|
next = append(next, fieldScan{styp, index})
|
}
|
}
|
if ok {
|
break
|
}
|
}
|
return
|
}
|
|
// FieldByName returns the struct field with the given name
|
// and a boolean to indicate if the field was found.
|
func (t *structType) FieldByName(name string) (f StructField, present bool) {
|
// Quick check for top-level name, or struct without embedded fields.
|
hasEmbeds := false
|
if name != "" {
|
for i := range t.fields {
|
tf := &t.fields[i]
|
if tf.name.name() == name {
|
return t.Field(i), true
|
}
|
if tf.embedded() {
|
hasEmbeds = true
|
}
|
}
|
}
|
if !hasEmbeds {
|
return
|
}
|
return t.FieldByNameFunc(func(s string) bool { return s == name })
|
}
|
|
// TypeOf returns the reflection Type that represents the dynamic type of i.
|
// If i is a nil interface value, TypeOf returns nil.
|
func TypeOf(i interface{}) Type {
|
eface := *(*emptyInterface)(unsafe.Pointer(&i))
|
return toType(eface.typ)
|
}
|
|
// ptrMap is the cache for PtrTo.
|
var ptrMap sync.Map // map[*rtype]*ptrType
|
|
// PtrTo returns the pointer type with element t.
|
// For example, if t represents type Foo, PtrTo(t) represents *Foo.
|
func PtrTo(t Type) Type {
|
return t.(*rtype).ptrTo()
|
}
|
|
func (t *rtype) ptrTo() *rtype {
|
if t.ptrToThis != 0 {
|
return t.typeOff(t.ptrToThis)
|
}
|
|
// Check the cache.
|
if pi, ok := ptrMap.Load(t); ok {
|
return &pi.(*ptrType).rtype
|
}
|
|
// Look in known types.
|
s := "*" + t.String()
|
for _, tt := range typesByString(s) {
|
p := (*ptrType)(unsafe.Pointer(tt))
|
if p.elem != t {
|
continue
|
}
|
pi, _ := ptrMap.LoadOrStore(t, p)
|
return &pi.(*ptrType).rtype
|
}
|
|
// Create a new ptrType starting with the description
|
// of an *unsafe.Pointer.
|
var iptr interface{} = (*unsafe.Pointer)(nil)
|
prototype := *(**ptrType)(unsafe.Pointer(&iptr))
|
pp := *prototype
|
|
pp.str = resolveReflectName(newName(s, "", false))
|
pp.ptrToThis = 0
|
|
// For the type structures linked into the binary, the
|
// compiler provides a good hash of the string.
|
// Create a good hash for the new string by using
|
// the FNV-1 hash's mixing function to combine the
|
// old hash and the new "*".
|
pp.hash = fnv1(t.hash, '*')
|
|
pp.elem = t
|
|
pi, _ := ptrMap.LoadOrStore(t, &pp)
|
return &pi.(*ptrType).rtype
|
}
|
|
// fnv1 incorporates the list of bytes into the hash x using the FNV-1 hash function.
|
func fnv1(x uint32, list ...byte) uint32 {
|
for _, b := range list {
|
x = x*16777619 ^ uint32(b)
|
}
|
return x
|
}
|
|
func (t *rtype) Implements(u Type) bool {
|
if u == nil {
|
panic("reflect: nil type passed to Type.Implements")
|
}
|
if u.Kind() != Interface {
|
panic("reflect: non-interface type passed to Type.Implements")
|
}
|
return implements(u.(*rtype), t)
|
}
|
|
func (t *rtype) AssignableTo(u Type) bool {
|
if u == nil {
|
panic("reflect: nil type passed to Type.AssignableTo")
|
}
|
uu := u.(*rtype)
|
return directlyAssignable(uu, t) || implements(uu, t)
|
}
|
|
func (t *rtype) ConvertibleTo(u Type) bool {
|
if u == nil {
|
panic("reflect: nil type passed to Type.ConvertibleTo")
|
}
|
uu := u.(*rtype)
|
return convertOp(uu, t) != nil
|
}
|
|
func (t *rtype) Comparable() bool {
|
return t.alg != nil && t.alg.equal != nil
|
}
|
|
// implements reports whether the type V implements the interface type T.
|
func implements(T, V *rtype) bool {
|
if T.Kind() != Interface {
|
return false
|
}
|
t := (*interfaceType)(unsafe.Pointer(T))
|
if len(t.methods) == 0 {
|
return true
|
}
|
|
// The same algorithm applies in both cases, but the
|
// method tables for an interface type and a concrete type
|
// are different, so the code is duplicated.
|
// In both cases the algorithm is a linear scan over the two
|
// lists - T's methods and V's methods - simultaneously.
|
// Since method tables are stored in a unique sorted order
|
// (alphabetical, with no duplicate method names), the scan
|
// through V's methods must hit a match for each of T's
|
// methods along the way, or else V does not implement T.
|
// This lets us run the scan in overall linear time instead of
|
// the quadratic time a naive search would require.
|
// See also ../runtime/iface.go.
|
if V.Kind() == Interface {
|
v := (*interfaceType)(unsafe.Pointer(V))
|
i := 0
|
for j := 0; j < len(v.methods); j++ {
|
tm := &t.methods[i]
|
tmName := t.nameOff(tm.name)
|
vm := &v.methods[j]
|
vmName := V.nameOff(vm.name)
|
if vmName.name() == tmName.name() && V.typeOff(vm.typ) == t.typeOff(tm.typ) {
|
if !tmName.isExported() {
|
tmPkgPath := tmName.pkgPath()
|
if tmPkgPath == "" {
|
tmPkgPath = t.pkgPath.name()
|
}
|
vmPkgPath := vmName.pkgPath()
|
if vmPkgPath == "" {
|
vmPkgPath = v.pkgPath.name()
|
}
|
if tmPkgPath != vmPkgPath {
|
continue
|
}
|
}
|
if i++; i >= len(t.methods) {
|
return true
|
}
|
}
|
}
|
return false
|
}
|
|
v := V.uncommon()
|
if v == nil {
|
return false
|
}
|
i := 0
|
vmethods := v.methods()
|
for j := 0; j < int(v.mcount); j++ {
|
tm := &t.methods[i]
|
tmName := t.nameOff(tm.name)
|
vm := vmethods[j]
|
vmName := V.nameOff(vm.name)
|
if vmName.name() == tmName.name() && V.typeOff(vm.mtyp) == t.typeOff(tm.typ) {
|
if !tmName.isExported() {
|
tmPkgPath := tmName.pkgPath()
|
if tmPkgPath == "" {
|
tmPkgPath = t.pkgPath.name()
|
}
|
vmPkgPath := vmName.pkgPath()
|
if vmPkgPath == "" {
|
vmPkgPath = V.nameOff(v.pkgPath).name()
|
}
|
if tmPkgPath != vmPkgPath {
|
continue
|
}
|
}
|
if i++; i >= len(t.methods) {
|
return true
|
}
|
}
|
}
|
return false
|
}
|
|
// directlyAssignable reports whether a value x of type V can be directly
|
// assigned (using memmove) to a value of type T.
|
// https://golang.org/doc/go_spec.html#Assignability
|
// Ignoring the interface rules (implemented elsewhere)
|
// and the ideal constant rules (no ideal constants at run time).
|
func directlyAssignable(T, V *rtype) bool {
|
// x's type V is identical to T?
|
if T == V {
|
return true
|
}
|
|
// Otherwise at least one of T and V must not be defined
|
// and they must have the same kind.
|
if T.Name() != "" && V.Name() != "" || T.Kind() != V.Kind() {
|
return false
|
}
|
|
// x's type T and V must have identical underlying types.
|
return haveIdenticalUnderlyingType(T, V, true)
|
}
|
|
func haveIdenticalType(T, V Type, cmpTags bool) bool {
|
if cmpTags {
|
return T == V
|
}
|
|
if T.Name() != V.Name() || T.Kind() != V.Kind() {
|
return false
|
}
|
|
return haveIdenticalUnderlyingType(T.common(), V.common(), false)
|
}
|
|
func haveIdenticalUnderlyingType(T, V *rtype, cmpTags bool) bool {
|
if T == V {
|
return true
|
}
|
|
kind := T.Kind()
|
if kind != V.Kind() {
|
return false
|
}
|
|
// Non-composite types of equal kind have same underlying type
|
// (the predefined instance of the type).
|
if Bool <= kind && kind <= Complex128 || kind == String || kind == UnsafePointer {
|
return true
|
}
|
|
// Composite types.
|
switch kind {
|
case Array:
|
return T.Len() == V.Len() && haveIdenticalType(T.Elem(), V.Elem(), cmpTags)
|
|
case Chan:
|
// Special case:
|
// x is a bidirectional channel value, T is a channel type,
|
// and x's type V and T have identical element types.
|
if V.ChanDir() == BothDir && haveIdenticalType(T.Elem(), V.Elem(), cmpTags) {
|
return true
|
}
|
|
// Otherwise continue test for identical underlying type.
|
return V.ChanDir() == T.ChanDir() && haveIdenticalType(T.Elem(), V.Elem(), cmpTags)
|
|
case Func:
|
t := (*funcType)(unsafe.Pointer(T))
|
v := (*funcType)(unsafe.Pointer(V))
|
if t.outCount != v.outCount || t.inCount != v.inCount {
|
return false
|
}
|
for i := 0; i < t.NumIn(); i++ {
|
if !haveIdenticalType(t.In(i), v.In(i), cmpTags) {
|
return false
|
}
|
}
|
for i := 0; i < t.NumOut(); i++ {
|
if !haveIdenticalType(t.Out(i), v.Out(i), cmpTags) {
|
return false
|
}
|
}
|
return true
|
|
case Interface:
|
t := (*interfaceType)(unsafe.Pointer(T))
|
v := (*interfaceType)(unsafe.Pointer(V))
|
if len(t.methods) == 0 && len(v.methods) == 0 {
|
return true
|
}
|
// Might have the same methods but still
|
// need a run time conversion.
|
return false
|
|
case Map:
|
return haveIdenticalType(T.Key(), V.Key(), cmpTags) && haveIdenticalType(T.Elem(), V.Elem(), cmpTags)
|
|
case Ptr, Slice:
|
return haveIdenticalType(T.Elem(), V.Elem(), cmpTags)
|
|
case Struct:
|
t := (*structType)(unsafe.Pointer(T))
|
v := (*structType)(unsafe.Pointer(V))
|
if len(t.fields) != len(v.fields) {
|
return false
|
}
|
if t.pkgPath.name() != v.pkgPath.name() {
|
return false
|
}
|
for i := range t.fields {
|
tf := &t.fields[i]
|
vf := &v.fields[i]
|
if tf.name.name() != vf.name.name() {
|
return false
|
}
|
if !haveIdenticalType(tf.typ, vf.typ, cmpTags) {
|
return false
|
}
|
if cmpTags && tf.name.tag() != vf.name.tag() {
|
return false
|
}
|
if tf.offsetEmbed != vf.offsetEmbed {
|
return false
|
}
|
}
|
return true
|
}
|
|
return false
|
}
|
|
// typelinks is implemented in package runtime.
|
// It returns a slice of the sections in each module,
|
// and a slice of *rtype offsets in each module.
|
//
|
// The types in each module are sorted by string. That is, the first
|
// two linked types of the first module are:
|
//
|
// d0 := sections[0]
|
// t1 := (*rtype)(add(d0, offset[0][0]))
|
// t2 := (*rtype)(add(d0, offset[0][1]))
|
//
|
// and
|
//
|
// t1.String() < t2.String()
|
//
|
// Note that strings are not unique identifiers for types:
|
// there can be more than one with a given string.
|
// Only types we might want to look up are included:
|
// pointers, channels, maps, slices, and arrays.
|
func typelinks() (sections []unsafe.Pointer, offset [][]int32)
|
|
func rtypeOff(section unsafe.Pointer, off int32) *rtype {
|
return (*rtype)(add(section, uintptr(off), "sizeof(rtype) > 0"))
|
}
|
|
// typesByString returns the subslice of typelinks() whose elements have
|
// the given string representation.
|
// It may be empty (no known types with that string) or may have
|
// multiple elements (multiple types with that string).
|
func typesByString(s string) []*rtype {
|
sections, offset := typelinks()
|
var ret []*rtype
|
|
for offsI, offs := range offset {
|
section := sections[offsI]
|
|
// We are looking for the first index i where the string becomes >= s.
|
// This is a copy of sort.Search, with f(h) replaced by (*typ[h].String() >= s).
|
i, j := 0, len(offs)
|
for i < j {
|
h := i + (j-i)/2 // avoid overflow when computing h
|
// i ≤ h < j
|
if !(rtypeOff(section, offs[h]).String() >= s) {
|
i = h + 1 // preserves f(i-1) == false
|
} else {
|
j = h // preserves f(j) == true
|
}
|
}
|
// i == j, f(i-1) == false, and f(j) (= f(i)) == true => answer is i.
|
|
// Having found the first, linear scan forward to find the last.
|
// We could do a second binary search, but the caller is going
|
// to do a linear scan anyway.
|
for j := i; j < len(offs); j++ {
|
typ := rtypeOff(section, offs[j])
|
if typ.String() != s {
|
break
|
}
|
ret = append(ret, typ)
|
}
|
}
|
return ret
|
}
|
|
// The lookupCache caches ArrayOf, ChanOf, MapOf and SliceOf lookups.
|
var lookupCache sync.Map // map[cacheKey]*rtype
|
|
// A cacheKey is the key for use in the lookupCache.
|
// Four values describe any of the types we are looking for:
|
// type kind, one or two subtypes, and an extra integer.
|
type cacheKey struct {
|
kind Kind
|
t1 *rtype
|
t2 *rtype
|
extra uintptr
|
}
|
|
// The funcLookupCache caches FuncOf lookups.
|
// FuncOf does not share the common lookupCache since cacheKey is not
|
// sufficient to represent functions unambiguously.
|
var funcLookupCache struct {
|
sync.Mutex // Guards stores (but not loads) on m.
|
|
// m is a map[uint32][]*rtype keyed by the hash calculated in FuncOf.
|
// Elements of m are append-only and thus safe for concurrent reading.
|
m sync.Map
|
}
|
|
// ChanOf returns the channel type with the given direction and element type.
|
// For example, if t represents int, ChanOf(RecvDir, t) represents <-chan int.
|
//
|
// The gc runtime imposes a limit of 64 kB on channel element types.
|
// If t's size is equal to or exceeds this limit, ChanOf panics.
|
func ChanOf(dir ChanDir, t Type) Type {
|
typ := t.(*rtype)
|
|
// Look in cache.
|
ckey := cacheKey{Chan, typ, nil, uintptr(dir)}
|
if ch, ok := lookupCache.Load(ckey); ok {
|
return ch.(*rtype)
|
}
|
|
// This restriction is imposed by the gc compiler and the runtime.
|
if typ.size >= 1<<16 {
|
panic("reflect.ChanOf: element size too large")
|
}
|
|
// Look in known types.
|
// TODO: Precedence when constructing string.
|
var s string
|
switch dir {
|
default:
|
panic("reflect.ChanOf: invalid dir")
|
case SendDir:
|
s = "chan<- " + typ.String()
|
case RecvDir:
|
s = "<-chan " + typ.String()
|
case BothDir:
|
s = "chan " + typ.String()
|
}
|
for _, tt := range typesByString(s) {
|
ch := (*chanType)(unsafe.Pointer(tt))
|
if ch.elem == typ && ch.dir == uintptr(dir) {
|
ti, _ := lookupCache.LoadOrStore(ckey, tt)
|
return ti.(Type)
|
}
|
}
|
|
// Make a channel type.
|
var ichan interface{} = (chan unsafe.Pointer)(nil)
|
prototype := *(**chanType)(unsafe.Pointer(&ichan))
|
ch := *prototype
|
ch.tflag = 0
|
ch.dir = uintptr(dir)
|
ch.str = resolveReflectName(newName(s, "", false))
|
ch.hash = fnv1(typ.hash, 'c', byte(dir))
|
ch.elem = typ
|
|
ti, _ := lookupCache.LoadOrStore(ckey, &ch.rtype)
|
return ti.(Type)
|
}
|
|
func ismapkey(*rtype) bool // implemented in runtime
|
|
// MapOf returns the map type with the given key and element types.
|
// For example, if k represents int and e represents string,
|
// MapOf(k, e) represents map[int]string.
|
//
|
// If the key type is not a valid map key type (that is, if it does
|
// not implement Go's == operator), MapOf panics.
|
func MapOf(key, elem Type) Type {
|
ktyp := key.(*rtype)
|
etyp := elem.(*rtype)
|
|
if !ismapkey(ktyp) {
|
panic("reflect.MapOf: invalid key type " + ktyp.String())
|
}
|
|
// Look in cache.
|
ckey := cacheKey{Map, ktyp, etyp, 0}
|
if mt, ok := lookupCache.Load(ckey); ok {
|
return mt.(Type)
|
}
|
|
// Look in known types.
|
s := "map[" + ktyp.String() + "]" + etyp.String()
|
for _, tt := range typesByString(s) {
|
mt := (*mapType)(unsafe.Pointer(tt))
|
if mt.key == ktyp && mt.elem == etyp {
|
ti, _ := lookupCache.LoadOrStore(ckey, tt)
|
return ti.(Type)
|
}
|
}
|
|
// Make a map type.
|
// Note: flag values must match those used in the TMAP case
|
// in ../cmd/compile/internal/gc/reflect.go:dtypesym.
|
var imap interface{} = (map[unsafe.Pointer]unsafe.Pointer)(nil)
|
mt := **(**mapType)(unsafe.Pointer(&imap))
|
mt.str = resolveReflectName(newName(s, "", false))
|
mt.tflag = 0
|
mt.hash = fnv1(etyp.hash, 'm', byte(ktyp.hash>>24), byte(ktyp.hash>>16), byte(ktyp.hash>>8), byte(ktyp.hash))
|
mt.key = ktyp
|
mt.elem = etyp
|
mt.bucket = bucketOf(ktyp, etyp)
|
mt.flags = 0
|
if ktyp.size > maxKeySize {
|
mt.keysize = uint8(ptrSize)
|
mt.flags |= 1 // indirect key
|
} else {
|
mt.keysize = uint8(ktyp.size)
|
}
|
if etyp.size > maxValSize {
|
mt.valuesize = uint8(ptrSize)
|
mt.flags |= 2 // indirect value
|
} else {
|
mt.valuesize = uint8(etyp.size)
|
}
|
mt.bucketsize = uint16(mt.bucket.size)
|
if isReflexive(ktyp) {
|
mt.flags |= 4
|
}
|
if needKeyUpdate(ktyp) {
|
mt.flags |= 8
|
}
|
if hashMightPanic(ktyp) {
|
mt.flags |= 16
|
}
|
mt.ptrToThis = 0
|
|
ti, _ := lookupCache.LoadOrStore(ckey, &mt.rtype)
|
return ti.(Type)
|
}
|
|
// TODO(crawshaw): as these funcTypeFixedN structs have no methods,
|
// they could be defined at runtime using the StructOf function.
|
type funcTypeFixed4 struct {
|
funcType
|
args [4]*rtype
|
}
|
type funcTypeFixed8 struct {
|
funcType
|
args [8]*rtype
|
}
|
type funcTypeFixed16 struct {
|
funcType
|
args [16]*rtype
|
}
|
type funcTypeFixed32 struct {
|
funcType
|
args [32]*rtype
|
}
|
type funcTypeFixed64 struct {
|
funcType
|
args [64]*rtype
|
}
|
type funcTypeFixed128 struct {
|
funcType
|
args [128]*rtype
|
}
|
|
// FuncOf returns the function type with the given argument and result types.
|
// For example if k represents int and e represents string,
|
// FuncOf([]Type{k}, []Type{e}, false) represents func(int) string.
|
//
|
// The variadic argument controls whether the function is variadic. FuncOf
|
// panics if the in[len(in)-1] does not represent a slice and variadic is
|
// true.
|
func FuncOf(in, out []Type, variadic bool) Type {
|
if variadic && (len(in) == 0 || in[len(in)-1].Kind() != Slice) {
|
panic("reflect.FuncOf: last arg of variadic func must be slice")
|
}
|
|
// Make a func type.
|
var ifunc interface{} = (func())(nil)
|
prototype := *(**funcType)(unsafe.Pointer(&ifunc))
|
n := len(in) + len(out)
|
|
var ft *funcType
|
var args []*rtype
|
switch {
|
case n <= 4:
|
fixed := new(funcTypeFixed4)
|
args = fixed.args[:0:len(fixed.args)]
|
ft = &fixed.funcType
|
case n <= 8:
|
fixed := new(funcTypeFixed8)
|
args = fixed.args[:0:len(fixed.args)]
|
ft = &fixed.funcType
|
case n <= 16:
|
fixed := new(funcTypeFixed16)
|
args = fixed.args[:0:len(fixed.args)]
|
ft = &fixed.funcType
|
case n <= 32:
|
fixed := new(funcTypeFixed32)
|
args = fixed.args[:0:len(fixed.args)]
|
ft = &fixed.funcType
|
case n <= 64:
|
fixed := new(funcTypeFixed64)
|
args = fixed.args[:0:len(fixed.args)]
|
ft = &fixed.funcType
|
case n <= 128:
|
fixed := new(funcTypeFixed128)
|
args = fixed.args[:0:len(fixed.args)]
|
ft = &fixed.funcType
|
default:
|
panic("reflect.FuncOf: too many arguments")
|
}
|
*ft = *prototype
|
|
// Build a hash and minimally populate ft.
|
var hash uint32
|
for _, in := range in {
|
t := in.(*rtype)
|
args = append(args, t)
|
hash = fnv1(hash, byte(t.hash>>24), byte(t.hash>>16), byte(t.hash>>8), byte(t.hash))
|
}
|
if variadic {
|
hash = fnv1(hash, 'v')
|
}
|
hash = fnv1(hash, '.')
|
for _, out := range out {
|
t := out.(*rtype)
|
args = append(args, t)
|
hash = fnv1(hash, byte(t.hash>>24), byte(t.hash>>16), byte(t.hash>>8), byte(t.hash))
|
}
|
if len(args) > 50 {
|
panic("reflect.FuncOf does not support more than 50 arguments")
|
}
|
ft.tflag = 0
|
ft.hash = hash
|
ft.inCount = uint16(len(in))
|
ft.outCount = uint16(len(out))
|
if variadic {
|
ft.outCount |= 1 << 15
|
}
|
|
// Look in cache.
|
if ts, ok := funcLookupCache.m.Load(hash); ok {
|
for _, t := range ts.([]*rtype) {
|
if haveIdenticalUnderlyingType(&ft.rtype, t, true) {
|
return t
|
}
|
}
|
}
|
|
// Not in cache, lock and retry.
|
funcLookupCache.Lock()
|
defer funcLookupCache.Unlock()
|
if ts, ok := funcLookupCache.m.Load(hash); ok {
|
for _, t := range ts.([]*rtype) {
|
if haveIdenticalUnderlyingType(&ft.rtype, t, true) {
|
return t
|
}
|
}
|
}
|
|
addToCache := func(tt *rtype) Type {
|
var rts []*rtype
|
if rti, ok := funcLookupCache.m.Load(hash); ok {
|
rts = rti.([]*rtype)
|
}
|
funcLookupCache.m.Store(hash, append(rts, tt))
|
return tt
|
}
|
|
// Look in known types for the same string representation.
|
str := funcStr(ft)
|
for _, tt := range typesByString(str) {
|
if haveIdenticalUnderlyingType(&ft.rtype, tt, true) {
|
return addToCache(tt)
|
}
|
}
|
|
// Populate the remaining fields of ft and store in cache.
|
ft.str = resolveReflectName(newName(str, "", false))
|
ft.ptrToThis = 0
|
return addToCache(&ft.rtype)
|
}
|
|
// funcStr builds a string representation of a funcType.
|
func funcStr(ft *funcType) string {
|
repr := make([]byte, 0, 64)
|
repr = append(repr, "func("...)
|
for i, t := range ft.in() {
|
if i > 0 {
|
repr = append(repr, ", "...)
|
}
|
if ft.IsVariadic() && i == int(ft.inCount)-1 {
|
repr = append(repr, "..."...)
|
repr = append(repr, (*sliceType)(unsafe.Pointer(t)).elem.String()...)
|
} else {
|
repr = append(repr, t.String()...)
|
}
|
}
|
repr = append(repr, ')')
|
out := ft.out()
|
if len(out) == 1 {
|
repr = append(repr, ' ')
|
} else if len(out) > 1 {
|
repr = append(repr, " ("...)
|
}
|
for i, t := range out {
|
if i > 0 {
|
repr = append(repr, ", "...)
|
}
|
repr = append(repr, t.String()...)
|
}
|
if len(out) > 1 {
|
repr = append(repr, ')')
|
}
|
return string(repr)
|
}
|
|
// isReflexive reports whether the == operation on the type is reflexive.
|
// That is, x == x for all values x of type t.
|
func isReflexive(t *rtype) bool {
|
switch t.Kind() {
|
case Bool, Int, Int8, Int16, Int32, Int64, Uint, Uint8, Uint16, Uint32, Uint64, Uintptr, Chan, Ptr, String, UnsafePointer:
|
return true
|
case Float32, Float64, Complex64, Complex128, Interface:
|
return false
|
case Array:
|
tt := (*arrayType)(unsafe.Pointer(t))
|
return isReflexive(tt.elem)
|
case Struct:
|
tt := (*structType)(unsafe.Pointer(t))
|
for _, f := range tt.fields {
|
if !isReflexive(f.typ) {
|
return false
|
}
|
}
|
return true
|
default:
|
// Func, Map, Slice, Invalid
|
panic("isReflexive called on non-key type " + t.String())
|
}
|
}
|
|
// needKeyUpdate reports whether map overwrites require the key to be copied.
|
func needKeyUpdate(t *rtype) bool {
|
switch t.Kind() {
|
case Bool, Int, Int8, Int16, Int32, Int64, Uint, Uint8, Uint16, Uint32, Uint64, Uintptr, Chan, Ptr, UnsafePointer:
|
return false
|
case Float32, Float64, Complex64, Complex128, Interface, String:
|
// Float keys can be updated from +0 to -0.
|
// String keys can be updated to use a smaller backing store.
|
// Interfaces might have floats of strings in them.
|
return true
|
case Array:
|
tt := (*arrayType)(unsafe.Pointer(t))
|
return needKeyUpdate(tt.elem)
|
case Struct:
|
tt := (*structType)(unsafe.Pointer(t))
|
for _, f := range tt.fields {
|
if needKeyUpdate(f.typ) {
|
return true
|
}
|
}
|
return false
|
default:
|
// Func, Map, Slice, Invalid
|
panic("needKeyUpdate called on non-key type " + t.String())
|
}
|
}
|
|
// hashMightPanic reports whether the hash of a map key of type t might panic.
|
func hashMightPanic(t *rtype) bool {
|
switch t.Kind() {
|
case Interface:
|
return true
|
case Array:
|
tt := (*arrayType)(unsafe.Pointer(t))
|
return hashMightPanic(tt.elem)
|
case Struct:
|
tt := (*structType)(unsafe.Pointer(t))
|
for _, f := range tt.fields {
|
if hashMightPanic(f.typ) {
|
return true
|
}
|
}
|
return false
|
default:
|
return false
|
}
|
}
|
|
// Make sure these routines stay in sync with ../../runtime/map.go!
|
// These types exist only for GC, so we only fill out GC relevant info.
|
// Currently, that's just size and the GC program. We also fill in string
|
// for possible debugging use.
|
const (
|
bucketSize uintptr = 8
|
maxKeySize uintptr = 128
|
maxValSize uintptr = 128
|
)
|
|
func bucketOf(ktyp, etyp *rtype) *rtype {
|
// See comment on hmap.overflow in ../runtime/map.go.
|
var kind uint8
|
if ktyp.kind&kindNoPointers != 0 && etyp.kind&kindNoPointers != 0 &&
|
ktyp.size <= maxKeySize && etyp.size <= maxValSize {
|
kind = kindNoPointers
|
}
|
|
if ktyp.size > maxKeySize {
|
ktyp = PtrTo(ktyp).(*rtype)
|
}
|
if etyp.size > maxValSize {
|
etyp = PtrTo(etyp).(*rtype)
|
}
|
|
// Prepare GC data if any.
|
// A bucket is at most bucketSize*(1+maxKeySize+maxValSize)+2*ptrSize bytes,
|
// or 2072 bytes, or 259 pointer-size words, or 33 bytes of pointer bitmap.
|
// Note that since the key and value are known to be <= 128 bytes,
|
// they're guaranteed to have bitmaps instead of GC programs.
|
var gcdata *byte
|
var ptrdata uintptr
|
var overflowPad uintptr
|
|
// On NaCl, pad if needed to make overflow end at the proper struct alignment.
|
// On other systems, align > ptrSize is not possible.
|
if runtime.GOARCH == "amd64p32" && (ktyp.align > ptrSize || etyp.align > ptrSize) {
|
overflowPad = ptrSize
|
}
|
size := bucketSize*(1+ktyp.size+etyp.size) + overflowPad + ptrSize
|
if size&uintptr(ktyp.align-1) != 0 || size&uintptr(etyp.align-1) != 0 {
|
panic("reflect: bad size computation in MapOf")
|
}
|
|
if kind != kindNoPointers {
|
nptr := (bucketSize*(1+ktyp.size+etyp.size) + ptrSize) / ptrSize
|
mask := make([]byte, (nptr+7)/8)
|
base := bucketSize / ptrSize
|
|
if ktyp.kind&kindNoPointers == 0 {
|
if ktyp.kind&kindGCProg != 0 {
|
panic("reflect: unexpected GC program in MapOf")
|
}
|
kmask := (*[16]byte)(unsafe.Pointer(ktyp.gcdata))
|
for i := uintptr(0); i < ktyp.ptrdata/ptrSize; i++ {
|
if (kmask[i/8]>>(i%8))&1 != 0 {
|
for j := uintptr(0); j < bucketSize; j++ {
|
word := base + j*ktyp.size/ptrSize + i
|
mask[word/8] |= 1 << (word % 8)
|
}
|
}
|
}
|
}
|
base += bucketSize * ktyp.size / ptrSize
|
|
if etyp.kind&kindNoPointers == 0 {
|
if etyp.kind&kindGCProg != 0 {
|
panic("reflect: unexpected GC program in MapOf")
|
}
|
emask := (*[16]byte)(unsafe.Pointer(etyp.gcdata))
|
for i := uintptr(0); i < etyp.ptrdata/ptrSize; i++ {
|
if (emask[i/8]>>(i%8))&1 != 0 {
|
for j := uintptr(0); j < bucketSize; j++ {
|
word := base + j*etyp.size/ptrSize + i
|
mask[word/8] |= 1 << (word % 8)
|
}
|
}
|
}
|
}
|
base += bucketSize * etyp.size / ptrSize
|
base += overflowPad / ptrSize
|
|
word := base
|
mask[word/8] |= 1 << (word % 8)
|
gcdata = &mask[0]
|
ptrdata = (word + 1) * ptrSize
|
|
// overflow word must be last
|
if ptrdata != size {
|
panic("reflect: bad layout computation in MapOf")
|
}
|
}
|
|
b := &rtype{
|
align: ptrSize,
|
size: size,
|
kind: kind,
|
ptrdata: ptrdata,
|
gcdata: gcdata,
|
}
|
if overflowPad > 0 {
|
b.align = 8
|
}
|
s := "bucket(" + ktyp.String() + "," + etyp.String() + ")"
|
b.str = resolveReflectName(newName(s, "", false))
|
return b
|
}
|
|
// SliceOf returns the slice type with element type t.
|
// For example, if t represents int, SliceOf(t) represents []int.
|
func SliceOf(t Type) Type {
|
typ := t.(*rtype)
|
|
// Look in cache.
|
ckey := cacheKey{Slice, typ, nil, 0}
|
if slice, ok := lookupCache.Load(ckey); ok {
|
return slice.(Type)
|
}
|
|
// Look in known types.
|
s := "[]" + typ.String()
|
for _, tt := range typesByString(s) {
|
slice := (*sliceType)(unsafe.Pointer(tt))
|
if slice.elem == typ {
|
ti, _ := lookupCache.LoadOrStore(ckey, tt)
|
return ti.(Type)
|
}
|
}
|
|
// Make a slice type.
|
var islice interface{} = ([]unsafe.Pointer)(nil)
|
prototype := *(**sliceType)(unsafe.Pointer(&islice))
|
slice := *prototype
|
slice.tflag = 0
|
slice.str = resolveReflectName(newName(s, "", false))
|
slice.hash = fnv1(typ.hash, '[')
|
slice.elem = typ
|
slice.ptrToThis = 0
|
|
ti, _ := lookupCache.LoadOrStore(ckey, &slice.rtype)
|
return ti.(Type)
|
}
|
|
// The structLookupCache caches StructOf lookups.
|
// StructOf does not share the common lookupCache since we need to pin
|
// the memory associated with *structTypeFixedN.
|
var structLookupCache struct {
|
sync.Mutex // Guards stores (but not loads) on m.
|
|
// m is a map[uint32][]Type keyed by the hash calculated in StructOf.
|
// Elements in m are append-only and thus safe for concurrent reading.
|
m sync.Map
|
}
|
|
type structTypeUncommon struct {
|
structType
|
u uncommonType
|
}
|
|
// isLetter reports whether a given 'rune' is classified as a Letter.
|
func isLetter(ch rune) bool {
|
return 'a' <= ch && ch <= 'z' || 'A' <= ch && ch <= 'Z' || ch == '_' || ch >= utf8.RuneSelf && unicode.IsLetter(ch)
|
}
|
|
// isValidFieldName checks if a string is a valid (struct) field name or not.
|
//
|
// According to the language spec, a field name should be an identifier.
|
//
|
// identifier = letter { letter | unicode_digit } .
|
// letter = unicode_letter | "_" .
|
func isValidFieldName(fieldName string) bool {
|
for i, c := range fieldName {
|
if i == 0 && !isLetter(c) {
|
return false
|
}
|
|
if !(isLetter(c) || unicode.IsDigit(c)) {
|
return false
|
}
|
}
|
|
return len(fieldName) > 0
|
}
|
|
// StructOf returns the struct type containing fields.
|
// The Offset and Index fields are ignored and computed as they would be
|
// by the compiler.
|
//
|
// StructOf currently does not generate wrapper methods for embedded
|
// fields and panics if passed unexported StructFields.
|
// These limitations may be lifted in a future version.
|
func StructOf(fields []StructField) Type {
|
var (
|
hash = fnv1(0, []byte("struct {")...)
|
size uintptr
|
typalign uint8
|
comparable = true
|
hashable = true
|
methods []method
|
|
fs = make([]structField, len(fields))
|
repr = make([]byte, 0, 64)
|
fset = map[string]struct{}{} // fields' names
|
|
hasPtr = false // records whether at least one struct-field is a pointer
|
hasGCProg = false // records whether a struct-field type has a GCProg
|
)
|
|
lastzero := uintptr(0)
|
repr = append(repr, "struct {"...)
|
for i, field := range fields {
|
if field.Name == "" {
|
panic("reflect.StructOf: field " + strconv.Itoa(i) + " has no name")
|
}
|
if !isValidFieldName(field.Name) {
|
panic("reflect.StructOf: field " + strconv.Itoa(i) + " has invalid name")
|
}
|
if field.Type == nil {
|
panic("reflect.StructOf: field " + strconv.Itoa(i) + " has no type")
|
}
|
f := runtimeStructField(field)
|
ft := f.typ
|
if ft.kind&kindGCProg != 0 {
|
hasGCProg = true
|
}
|
if ft.pointers() {
|
hasPtr = true
|
}
|
|
// Update string and hash
|
name := f.name.name()
|
hash = fnv1(hash, []byte(name)...)
|
repr = append(repr, (" " + name)...)
|
if f.embedded() {
|
// Embedded field
|
if f.typ.Kind() == Ptr {
|
// Embedded ** and *interface{} are illegal
|
elem := ft.Elem()
|
if k := elem.Kind(); k == Ptr || k == Interface {
|
panic("reflect.StructOf: illegal embedded field type " + ft.String())
|
}
|
}
|
|
switch f.typ.Kind() {
|
case Interface:
|
ift := (*interfaceType)(unsafe.Pointer(ft))
|
for im, m := range ift.methods {
|
if ift.nameOff(m.name).pkgPath() != "" {
|
// TODO(sbinet). Issue 15924.
|
panic("reflect: embedded interface with unexported method(s) not implemented")
|
}
|
|
var (
|
mtyp = ift.typeOff(m.typ)
|
ifield = i
|
imethod = im
|
ifn Value
|
tfn Value
|
)
|
|
if ft.kind&kindDirectIface != 0 {
|
tfn = MakeFunc(mtyp, func(in []Value) []Value {
|
var args []Value
|
var recv = in[0]
|
if len(in) > 1 {
|
args = in[1:]
|
}
|
return recv.Field(ifield).Method(imethod).Call(args)
|
})
|
ifn = MakeFunc(mtyp, func(in []Value) []Value {
|
var args []Value
|
var recv = in[0]
|
if len(in) > 1 {
|
args = in[1:]
|
}
|
return recv.Field(ifield).Method(imethod).Call(args)
|
})
|
} else {
|
tfn = MakeFunc(mtyp, func(in []Value) []Value {
|
var args []Value
|
var recv = in[0]
|
if len(in) > 1 {
|
args = in[1:]
|
}
|
return recv.Field(ifield).Method(imethod).Call(args)
|
})
|
ifn = MakeFunc(mtyp, func(in []Value) []Value {
|
var args []Value
|
var recv = Indirect(in[0])
|
if len(in) > 1 {
|
args = in[1:]
|
}
|
return recv.Field(ifield).Method(imethod).Call(args)
|
})
|
}
|
|
methods = append(methods, method{
|
name: resolveReflectName(ift.nameOff(m.name)),
|
mtyp: resolveReflectType(mtyp),
|
ifn: resolveReflectText(unsafe.Pointer(&ifn)),
|
tfn: resolveReflectText(unsafe.Pointer(&tfn)),
|
})
|
}
|
case Ptr:
|
ptr := (*ptrType)(unsafe.Pointer(ft))
|
if unt := ptr.uncommon(); unt != nil {
|
if i > 0 && unt.mcount > 0 {
|
// Issue 15924.
|
panic("reflect: embedded type with methods not implemented if type is not first field")
|
}
|
if len(fields) > 1 {
|
panic("reflect: embedded type with methods not implemented if there is more than one field")
|
}
|
for _, m := range unt.methods() {
|
mname := ptr.nameOff(m.name)
|
if mname.pkgPath() != "" {
|
// TODO(sbinet).
|
// Issue 15924.
|
panic("reflect: embedded interface with unexported method(s) not implemented")
|
}
|
methods = append(methods, method{
|
name: resolveReflectName(mname),
|
mtyp: resolveReflectType(ptr.typeOff(m.mtyp)),
|
ifn: resolveReflectText(ptr.textOff(m.ifn)),
|
tfn: resolveReflectText(ptr.textOff(m.tfn)),
|
})
|
}
|
}
|
if unt := ptr.elem.uncommon(); unt != nil {
|
for _, m := range unt.methods() {
|
mname := ptr.nameOff(m.name)
|
if mname.pkgPath() != "" {
|
// TODO(sbinet)
|
// Issue 15924.
|
panic("reflect: embedded interface with unexported method(s) not implemented")
|
}
|
methods = append(methods, method{
|
name: resolveReflectName(mname),
|
mtyp: resolveReflectType(ptr.elem.typeOff(m.mtyp)),
|
ifn: resolveReflectText(ptr.elem.textOff(m.ifn)),
|
tfn: resolveReflectText(ptr.elem.textOff(m.tfn)),
|
})
|
}
|
}
|
default:
|
if unt := ft.uncommon(); unt != nil {
|
if i > 0 && unt.mcount > 0 {
|
// Issue 15924.
|
panic("reflect: embedded type with methods not implemented if type is not first field")
|
}
|
if len(fields) > 1 && ft.kind&kindDirectIface != 0 {
|
panic("reflect: embedded type with methods not implemented for non-pointer type")
|
}
|
for _, m := range unt.methods() {
|
mname := ft.nameOff(m.name)
|
if mname.pkgPath() != "" {
|
// TODO(sbinet)
|
// Issue 15924.
|
panic("reflect: embedded interface with unexported method(s) not implemented")
|
}
|
methods = append(methods, method{
|
name: resolveReflectName(mname),
|
mtyp: resolveReflectType(ft.typeOff(m.mtyp)),
|
ifn: resolveReflectText(ft.textOff(m.ifn)),
|
tfn: resolveReflectText(ft.textOff(m.tfn)),
|
})
|
|
}
|
}
|
}
|
}
|
if _, dup := fset[name]; dup {
|
panic("reflect.StructOf: duplicate field " + name)
|
}
|
fset[name] = struct{}{}
|
|
hash = fnv1(hash, byte(ft.hash>>24), byte(ft.hash>>16), byte(ft.hash>>8), byte(ft.hash))
|
|
repr = append(repr, (" " + ft.String())...)
|
if f.name.tagLen() > 0 {
|
hash = fnv1(hash, []byte(f.name.tag())...)
|
repr = append(repr, (" " + strconv.Quote(f.name.tag()))...)
|
}
|
if i < len(fields)-1 {
|
repr = append(repr, ';')
|
}
|
|
comparable = comparable && (ft.alg.equal != nil)
|
hashable = hashable && (ft.alg.hash != nil)
|
|
offset := align(size, uintptr(ft.align))
|
if ft.align > typalign {
|
typalign = ft.align
|
}
|
size = offset + ft.size
|
f.offsetEmbed |= offset << 1
|
|
if ft.size == 0 {
|
lastzero = size
|
}
|
|
fs[i] = f
|
}
|
|
if size > 0 && lastzero == size {
|
// This is a non-zero sized struct that ends in a
|
// zero-sized field. We add an extra byte of padding,
|
// to ensure that taking the address of the final
|
// zero-sized field can't manufacture a pointer to the
|
// next object in the heap. See issue 9401.
|
size++
|
}
|
|
var typ *structType
|
var ut *uncommonType
|
|
if len(methods) == 0 {
|
t := new(structTypeUncommon)
|
typ = &t.structType
|
ut = &t.u
|
} else {
|
// A *rtype representing a struct is followed directly in memory by an
|
// array of method objects representing the methods attached to the
|
// struct. To get the same layout for a run time generated type, we
|
// need an array directly following the uncommonType memory.
|
// A similar strategy is used for funcTypeFixed4, ...funcTypeFixedN.
|
tt := New(StructOf([]StructField{
|
{Name: "S", Type: TypeOf(structType{})},
|
{Name: "U", Type: TypeOf(uncommonType{})},
|
{Name: "M", Type: ArrayOf(len(methods), TypeOf(methods[0]))},
|
}))
|
|
typ = (*structType)(unsafe.Pointer(tt.Elem().Field(0).UnsafeAddr()))
|
ut = (*uncommonType)(unsafe.Pointer(tt.Elem().Field(1).UnsafeAddr()))
|
|
copy(tt.Elem().Field(2).Slice(0, len(methods)).Interface().([]method), methods)
|
}
|
// TODO(sbinet): Once we allow embedding multiple types,
|
// methods will need to be sorted like the compiler does.
|
// TODO(sbinet): Once we allow non-exported methods, we will
|
// need to compute xcount as the number of exported methods.
|
ut.mcount = uint16(len(methods))
|
ut.xcount = ut.mcount
|
ut.moff = uint32(unsafe.Sizeof(uncommonType{}))
|
|
if len(fs) > 0 {
|
repr = append(repr, ' ')
|
}
|
repr = append(repr, '}')
|
hash = fnv1(hash, '}')
|
str := string(repr)
|
|
// Round the size up to be a multiple of the alignment.
|
size = align(size, uintptr(typalign))
|
|
// Make the struct type.
|
var istruct interface{} = struct{}{}
|
prototype := *(**structType)(unsafe.Pointer(&istruct))
|
*typ = *prototype
|
typ.fields = fs
|
|
// Look in cache.
|
if ts, ok := structLookupCache.m.Load(hash); ok {
|
for _, st := range ts.([]Type) {
|
t := st.common()
|
if haveIdenticalUnderlyingType(&typ.rtype, t, true) {
|
return t
|
}
|
}
|
}
|
|
// Not in cache, lock and retry.
|
structLookupCache.Lock()
|
defer structLookupCache.Unlock()
|
if ts, ok := structLookupCache.m.Load(hash); ok {
|
for _, st := range ts.([]Type) {
|
t := st.common()
|
if haveIdenticalUnderlyingType(&typ.rtype, t, true) {
|
return t
|
}
|
}
|
}
|
|
addToCache := func(t Type) Type {
|
var ts []Type
|
if ti, ok := structLookupCache.m.Load(hash); ok {
|
ts = ti.([]Type)
|
}
|
structLookupCache.m.Store(hash, append(ts, t))
|
return t
|
}
|
|
// Look in known types.
|
for _, t := range typesByString(str) {
|
if haveIdenticalUnderlyingType(&typ.rtype, t, true) {
|
// even if 't' wasn't a structType with methods, we should be ok
|
// as the 'u uncommonType' field won't be accessed except when
|
// tflag&tflagUncommon is set.
|
return addToCache(t)
|
}
|
}
|
|
typ.str = resolveReflectName(newName(str, "", false))
|
typ.tflag = 0
|
typ.hash = hash
|
typ.size = size
|
typ.align = typalign
|
typ.fieldAlign = typalign
|
typ.ptrToThis = 0
|
if len(methods) > 0 {
|
typ.tflag |= tflagUncommon
|
}
|
if !hasPtr {
|
typ.kind |= kindNoPointers
|
} else {
|
typ.kind &^= kindNoPointers
|
}
|
|
if hasGCProg {
|
lastPtrField := 0
|
for i, ft := range fs {
|
if ft.typ.pointers() {
|
lastPtrField = i
|
}
|
}
|
prog := []byte{0, 0, 0, 0} // will be length of prog
|
for i, ft := range fs {
|
if i > lastPtrField {
|
// gcprog should not include anything for any field after
|
// the last field that contains pointer data
|
break
|
}
|
// FIXME(sbinet) handle padding, fields smaller than a word
|
elemGC := (*[1 << 30]byte)(unsafe.Pointer(ft.typ.gcdata))[:]
|
elemPtrs := ft.typ.ptrdata / ptrSize
|
switch {
|
case ft.typ.kind&kindGCProg == 0 && ft.typ.ptrdata != 0:
|
// Element is small with pointer mask; use as literal bits.
|
mask := elemGC
|
// Emit 120-bit chunks of full bytes (max is 127 but we avoid using partial bytes).
|
var n uintptr
|
for n := elemPtrs; n > 120; n -= 120 {
|
prog = append(prog, 120)
|
prog = append(prog, mask[:15]...)
|
mask = mask[15:]
|
}
|
prog = append(prog, byte(n))
|
prog = append(prog, mask[:(n+7)/8]...)
|
case ft.typ.kind&kindGCProg != 0:
|
// Element has GC program; emit one element.
|
elemProg := elemGC[4 : 4+*(*uint32)(unsafe.Pointer(&elemGC[0]))-1]
|
prog = append(prog, elemProg...)
|
}
|
// Pad from ptrdata to size.
|
elemWords := ft.typ.size / ptrSize
|
if elemPtrs < elemWords {
|
// Emit literal 0 bit, then repeat as needed.
|
prog = append(prog, 0x01, 0x00)
|
if elemPtrs+1 < elemWords {
|
prog = append(prog, 0x81)
|
prog = appendVarint(prog, elemWords-elemPtrs-1)
|
}
|
}
|
}
|
*(*uint32)(unsafe.Pointer(&prog[0])) = uint32(len(prog) - 4)
|
typ.kind |= kindGCProg
|
typ.gcdata = &prog[0]
|
} else {
|
typ.kind &^= kindGCProg
|
bv := new(bitVector)
|
addTypeBits(bv, 0, typ.common())
|
if len(bv.data) > 0 {
|
typ.gcdata = &bv.data[0]
|
}
|
}
|
typ.ptrdata = typeptrdata(typ.common())
|
typ.alg = new(typeAlg)
|
if hashable {
|
typ.alg.hash = func(p unsafe.Pointer, seed uintptr) uintptr {
|
o := seed
|
for _, ft := range typ.fields {
|
pi := add(p, ft.offset(), "&x.field safe")
|
o = ft.typ.alg.hash(pi, o)
|
}
|
return o
|
}
|
}
|
|
if comparable {
|
typ.alg.equal = func(p, q unsafe.Pointer) bool {
|
for _, ft := range typ.fields {
|
pi := add(p, ft.offset(), "&x.field safe")
|
qi := add(q, ft.offset(), "&x.field safe")
|
if !ft.typ.alg.equal(pi, qi) {
|
return false
|
}
|
}
|
return true
|
}
|
}
|
|
switch {
|
case len(fs) == 1 && !ifaceIndir(fs[0].typ):
|
// structs of 1 direct iface type can be direct
|
typ.kind |= kindDirectIface
|
default:
|
typ.kind &^= kindDirectIface
|
}
|
|
return addToCache(&typ.rtype)
|
}
|
|
func runtimeStructField(field StructField) structField {
|
if field.PkgPath != "" {
|
panic("reflect.StructOf: StructOf does not allow unexported fields")
|
}
|
|
// Best-effort check for misuse.
|
// Since PkgPath is empty, not much harm done if Unicode lowercase slips through.
|
c := field.Name[0]
|
if 'a' <= c && c <= 'z' || c == '_' {
|
panic("reflect.StructOf: field \"" + field.Name + "\" is unexported but missing PkgPath")
|
}
|
|
offsetEmbed := uintptr(0)
|
if field.Anonymous {
|
offsetEmbed |= 1
|
}
|
|
resolveReflectType(field.Type.common()) // install in runtime
|
return structField{
|
name: newName(field.Name, string(field.Tag), true),
|
typ: field.Type.common(),
|
offsetEmbed: offsetEmbed,
|
}
|
}
|
|
// typeptrdata returns the length in bytes of the prefix of t
|
// containing pointer data. Anything after this offset is scalar data.
|
// keep in sync with ../cmd/compile/internal/gc/reflect.go
|
func typeptrdata(t *rtype) uintptr {
|
if !t.pointers() {
|
return 0
|
}
|
switch t.Kind() {
|
case Struct:
|
st := (*structType)(unsafe.Pointer(t))
|
// find the last field that has pointers.
|
field := 0
|
for i := range st.fields {
|
ft := st.fields[i].typ
|
if ft.pointers() {
|
field = i
|
}
|
}
|
f := st.fields[field]
|
return f.offset() + f.typ.ptrdata
|
|
default:
|
panic("reflect.typeptrdata: unexpected type, " + t.String())
|
}
|
}
|
|
// See cmd/compile/internal/gc/reflect.go for derivation of constant.
|
const maxPtrmaskBytes = 2048
|
|
// ArrayOf returns the array type with the given count and element type.
|
// For example, if t represents int, ArrayOf(5, t) represents [5]int.
|
//
|
// If the resulting type would be larger than the available address space,
|
// ArrayOf panics.
|
func ArrayOf(count int, elem Type) Type {
|
typ := elem.(*rtype)
|
|
// Look in cache.
|
ckey := cacheKey{Array, typ, nil, uintptr(count)}
|
if array, ok := lookupCache.Load(ckey); ok {
|
return array.(Type)
|
}
|
|
// Look in known types.
|
s := "[" + strconv.Itoa(count) + "]" + typ.String()
|
for _, tt := range typesByString(s) {
|
array := (*arrayType)(unsafe.Pointer(tt))
|
if array.elem == typ {
|
ti, _ := lookupCache.LoadOrStore(ckey, tt)
|
return ti.(Type)
|
}
|
}
|
|
// Make an array type.
|
var iarray interface{} = [1]unsafe.Pointer{}
|
prototype := *(**arrayType)(unsafe.Pointer(&iarray))
|
array := *prototype
|
array.tflag = 0
|
array.str = resolveReflectName(newName(s, "", false))
|
array.hash = fnv1(typ.hash, '[')
|
for n := uint32(count); n > 0; n >>= 8 {
|
array.hash = fnv1(array.hash, byte(n))
|
}
|
array.hash = fnv1(array.hash, ']')
|
array.elem = typ
|
array.ptrToThis = 0
|
if typ.size > 0 {
|
max := ^uintptr(0) / typ.size
|
if uintptr(count) > max {
|
panic("reflect.ArrayOf: array size would exceed virtual address space")
|
}
|
}
|
array.size = typ.size * uintptr(count)
|
if count > 0 && typ.ptrdata != 0 {
|
array.ptrdata = typ.size*uintptr(count-1) + typ.ptrdata
|
}
|
array.align = typ.align
|
array.fieldAlign = typ.fieldAlign
|
array.len = uintptr(count)
|
array.slice = SliceOf(elem).(*rtype)
|
|
array.kind &^= kindNoPointers
|
switch {
|
case typ.kind&kindNoPointers != 0 || array.size == 0:
|
// No pointers.
|
array.kind |= kindNoPointers
|
array.gcdata = nil
|
array.ptrdata = 0
|
|
case count == 1:
|
// In memory, 1-element array looks just like the element.
|
array.kind |= typ.kind & kindGCProg
|
array.gcdata = typ.gcdata
|
array.ptrdata = typ.ptrdata
|
|
case typ.kind&kindGCProg == 0 && array.size <= maxPtrmaskBytes*8*ptrSize:
|
// Element is small with pointer mask; array is still small.
|
// Create direct pointer mask by turning each 1 bit in elem
|
// into count 1 bits in larger mask.
|
mask := make([]byte, (array.ptrdata/ptrSize+7)/8)
|
elemMask := (*[1 << 30]byte)(unsafe.Pointer(typ.gcdata))[:]
|
elemWords := typ.size / ptrSize
|
for j := uintptr(0); j < typ.ptrdata/ptrSize; j++ {
|
if (elemMask[j/8]>>(j%8))&1 != 0 {
|
for i := uintptr(0); i < array.len; i++ {
|
k := i*elemWords + j
|
mask[k/8] |= 1 << (k % 8)
|
}
|
}
|
}
|
array.gcdata = &mask[0]
|
|
default:
|
// Create program that emits one element
|
// and then repeats to make the array.
|
prog := []byte{0, 0, 0, 0} // will be length of prog
|
elemGC := (*[1 << 30]byte)(unsafe.Pointer(typ.gcdata))[:]
|
elemPtrs := typ.ptrdata / ptrSize
|
if typ.kind&kindGCProg == 0 {
|
// Element is small with pointer mask; use as literal bits.
|
mask := elemGC
|
// Emit 120-bit chunks of full bytes (max is 127 but we avoid using partial bytes).
|
var n uintptr
|
for n = elemPtrs; n > 120; n -= 120 {
|
prog = append(prog, 120)
|
prog = append(prog, mask[:15]...)
|
mask = mask[15:]
|
}
|
prog = append(prog, byte(n))
|
prog = append(prog, mask[:(n+7)/8]...)
|
} else {
|
// Element has GC program; emit one element.
|
elemProg := elemGC[4 : 4+*(*uint32)(unsafe.Pointer(&elemGC[0]))-1]
|
prog = append(prog, elemProg...)
|
}
|
// Pad from ptrdata to size.
|
elemWords := typ.size / ptrSize
|
if elemPtrs < elemWords {
|
// Emit literal 0 bit, then repeat as needed.
|
prog = append(prog, 0x01, 0x00)
|
if elemPtrs+1 < elemWords {
|
prog = append(prog, 0x81)
|
prog = appendVarint(prog, elemWords-elemPtrs-1)
|
}
|
}
|
// Repeat count-1 times.
|
if elemWords < 0x80 {
|
prog = append(prog, byte(elemWords|0x80))
|
} else {
|
prog = append(prog, 0x80)
|
prog = appendVarint(prog, elemWords)
|
}
|
prog = appendVarint(prog, uintptr(count)-1)
|
prog = append(prog, 0)
|
*(*uint32)(unsafe.Pointer(&prog[0])) = uint32(len(prog) - 4)
|
array.kind |= kindGCProg
|
array.gcdata = &prog[0]
|
array.ptrdata = array.size // overestimate but ok; must match program
|
}
|
|
etyp := typ.common()
|
esize := etyp.Size()
|
ealg := etyp.alg
|
|
array.alg = new(typeAlg)
|
if ealg.equal != nil {
|
eequal := ealg.equal
|
array.alg.equal = func(p, q unsafe.Pointer) bool {
|
for i := 0; i < count; i++ {
|
pi := arrayAt(p, i, esize, "i < count")
|
qi := arrayAt(q, i, esize, "i < count")
|
if !eequal(pi, qi) {
|
return false
|
}
|
|
}
|
return true
|
}
|
}
|
if ealg.hash != nil {
|
ehash := ealg.hash
|
array.alg.hash = func(ptr unsafe.Pointer, seed uintptr) uintptr {
|
o := seed
|
for i := 0; i < count; i++ {
|
o = ehash(arrayAt(ptr, i, esize, "i < count"), o)
|
}
|
return o
|
}
|
}
|
|
switch {
|
case count == 1 && !ifaceIndir(typ):
|
// array of 1 direct iface type can be direct
|
array.kind |= kindDirectIface
|
default:
|
array.kind &^= kindDirectIface
|
}
|
|
ti, _ := lookupCache.LoadOrStore(ckey, &array.rtype)
|
return ti.(Type)
|
}
|
|
func appendVarint(x []byte, v uintptr) []byte {
|
for ; v >= 0x80; v >>= 7 {
|
x = append(x, byte(v|0x80))
|
}
|
x = append(x, byte(v))
|
return x
|
}
|
|
// toType converts from a *rtype to a Type that can be returned
|
// to the client of package reflect. In gc, the only concern is that
|
// a nil *rtype must be replaced by a nil Type, but in gccgo this
|
// function takes care of ensuring that multiple *rtype for the same
|
// type are coalesced into a single Type.
|
func toType(t *rtype) Type {
|
if t == nil {
|
return nil
|
}
|
return t
|
}
|
|
type layoutKey struct {
|
ftyp *funcType // function signature
|
rcvr *rtype // receiver type, or nil if none
|
}
|
|
type layoutType struct {
|
t *rtype
|
argSize uintptr // size of arguments
|
retOffset uintptr // offset of return values.
|
stack *bitVector
|
framePool *sync.Pool
|
}
|
|
var layoutCache sync.Map // map[layoutKey]layoutType
|
|
// funcLayout computes a struct type representing the layout of the
|
// function arguments and return values for the function type t.
|
// If rcvr != nil, rcvr specifies the type of the receiver.
|
// The returned type exists only for GC, so we only fill out GC relevant info.
|
// Currently, that's just size and the GC program. We also fill in
|
// the name for possible debugging use.
|
func funcLayout(t *funcType, rcvr *rtype) (frametype *rtype, argSize, retOffset uintptr, stk *bitVector, framePool *sync.Pool) {
|
if t.Kind() != Func {
|
panic("reflect: funcLayout of non-func type")
|
}
|
if rcvr != nil && rcvr.Kind() == Interface {
|
panic("reflect: funcLayout with interface receiver " + rcvr.String())
|
}
|
k := layoutKey{t, rcvr}
|
if lti, ok := layoutCache.Load(k); ok {
|
lt := lti.(layoutType)
|
return lt.t, lt.argSize, lt.retOffset, lt.stack, lt.framePool
|
}
|
|
// compute gc program & stack bitmap for arguments
|
ptrmap := new(bitVector)
|
var offset uintptr
|
if rcvr != nil {
|
// Reflect uses the "interface" calling convention for
|
// methods, where receivers take one word of argument
|
// space no matter how big they actually are.
|
if ifaceIndir(rcvr) || rcvr.pointers() {
|
ptrmap.append(1)
|
} else {
|
ptrmap.append(0)
|
}
|
offset += ptrSize
|
}
|
for _, arg := range t.in() {
|
offset += -offset & uintptr(arg.align-1)
|
addTypeBits(ptrmap, offset, arg)
|
offset += arg.size
|
}
|
argSize = offset
|
if runtime.GOARCH == "amd64p32" {
|
offset += -offset & (8 - 1)
|
}
|
offset += -offset & (ptrSize - 1)
|
retOffset = offset
|
for _, res := range t.out() {
|
offset += -offset & uintptr(res.align-1)
|
addTypeBits(ptrmap, offset, res)
|
offset += res.size
|
}
|
offset += -offset & (ptrSize - 1)
|
|
// build dummy rtype holding gc program
|
x := &rtype{
|
align: ptrSize,
|
size: offset,
|
ptrdata: uintptr(ptrmap.n) * ptrSize,
|
}
|
if runtime.GOARCH == "amd64p32" {
|
x.align = 8
|
}
|
if ptrmap.n > 0 {
|
x.gcdata = &ptrmap.data[0]
|
} else {
|
x.kind |= kindNoPointers
|
}
|
|
var s string
|
if rcvr != nil {
|
s = "methodargs(" + rcvr.String() + ")(" + t.String() + ")"
|
} else {
|
s = "funcargs(" + t.String() + ")"
|
}
|
x.str = resolveReflectName(newName(s, "", false))
|
|
// cache result for future callers
|
framePool = &sync.Pool{New: func() interface{} {
|
return unsafe_New(x)
|
}}
|
lti, _ := layoutCache.LoadOrStore(k, layoutType{
|
t: x,
|
argSize: argSize,
|
retOffset: retOffset,
|
stack: ptrmap,
|
framePool: framePool,
|
})
|
lt := lti.(layoutType)
|
return lt.t, lt.argSize, lt.retOffset, lt.stack, lt.framePool
|
}
|
|
// ifaceIndir reports whether t is stored indirectly in an interface value.
|
func ifaceIndir(t *rtype) bool {
|
return t.kind&kindDirectIface == 0
|
}
|
|
// Layout matches runtime.gobitvector (well enough).
|
type bitVector struct {
|
n uint32 // number of bits
|
data []byte
|
}
|
|
// append a bit to the bitmap.
|
func (bv *bitVector) append(bit uint8) {
|
if bv.n%8 == 0 {
|
bv.data = append(bv.data, 0)
|
}
|
bv.data[bv.n/8] |= bit << (bv.n % 8)
|
bv.n++
|
}
|
|
func addTypeBits(bv *bitVector, offset uintptr, t *rtype) {
|
if t.kind&kindNoPointers != 0 {
|
return
|
}
|
|
switch Kind(t.kind & kindMask) {
|
case Chan, Func, Map, Ptr, Slice, String, UnsafePointer:
|
// 1 pointer at start of representation
|
for bv.n < uint32(offset/uintptr(ptrSize)) {
|
bv.append(0)
|
}
|
bv.append(1)
|
|
case Interface:
|
// 2 pointers
|
for bv.n < uint32(offset/uintptr(ptrSize)) {
|
bv.append(0)
|
}
|
bv.append(1)
|
bv.append(1)
|
|
case Array:
|
// repeat inner type
|
tt := (*arrayType)(unsafe.Pointer(t))
|
for i := 0; i < int(tt.len); i++ {
|
addTypeBits(bv, offset+uintptr(i)*tt.elem.size, tt.elem)
|
}
|
|
case Struct:
|
// apply fields
|
tt := (*structType)(unsafe.Pointer(t))
|
for i := range tt.fields {
|
f := &tt.fields[i]
|
addTypeBits(bv, offset+f.offset(), f.typ)
|
}
|
}
|
}
|
