// Copyright 2016 The Go Authors. All rights reserved.
|
// Use of this source code is governed by a BSD-style
|
// license that can be found in the LICENSE file.
|
|
// +build ignore
|
|
// This program is run via "go generate" (via a directive in sort.go)
|
// to generate zfuncversion.go.
|
//
|
// It copies sort.go to zfuncversion.go, only retaining funcs which
|
// take a "data Interface" parameter, and renaming each to have a
|
// "_func" suffix and taking a "data lessSwap" instead. It then rewrites
|
// each internal function call to the appropriate _func variants.
|
|
package main
|
|
import (
|
"bytes"
|
"go/ast"
|
"go/format"
|
"go/parser"
|
"go/token"
|
"io/ioutil"
|
"log"
|
"regexp"
|
)
|
|
var fset = token.NewFileSet()
|
|
func main() {
|
af, err := parser.ParseFile(fset, "sort.go", nil, 0)
|
if err != nil {
|
log.Fatal(err)
|
}
|
af.Doc = nil
|
af.Imports = nil
|
af.Comments = nil
|
|
var newDecl []ast.Decl
|
for _, d := range af.Decls {
|
fd, ok := d.(*ast.FuncDecl)
|
if !ok {
|
continue
|
}
|
if fd.Recv != nil || fd.Name.IsExported() {
|
continue
|
}
|
typ := fd.Type
|
if len(typ.Params.List) < 1 {
|
continue
|
}
|
arg0 := typ.Params.List[0]
|
arg0Name := arg0.Names[0].Name
|
arg0Type := arg0.Type.(*ast.Ident)
|
if arg0Name != "data" || arg0Type.Name != "Interface" {
|
continue
|
}
|
arg0Type.Name = "lessSwap"
|
|
newDecl = append(newDecl, fd)
|
}
|
af.Decls = newDecl
|
ast.Walk(visitFunc(rewriteCalls), af)
|
|
var out bytes.Buffer
|
if err := format.Node(&out, fset, af); err != nil {
|
log.Fatalf("format.Node: %v", err)
|
}
|
|
// Get rid of blank lines after removal of comments.
|
src := regexp.MustCompile(`\n{2,}`).ReplaceAll(out.Bytes(), []byte("\n"))
|
|
// Add comments to each func, for the lost reader.
|
// This is so much easier than adding comments via the AST
|
// and trying to get position info correct.
|
src = regexp.MustCompile(`(?m)^func (\w+)`).ReplaceAll(src, []byte("\n// Auto-generated variant of sort.go:$1\nfunc ${1}_func"))
|
|
// Final gofmt.
|
src, err = format.Source(src)
|
if err != nil {
|
log.Fatalf("format.Source: %v on\n%s", err, src)
|
}
|
|
out.Reset()
|
out.WriteString(`// Code generated from sort.go using genzfunc.go; DO NOT EDIT.
|
|
// Copyright 2016 The Go Authors. All rights reserved.
|
// Use of this source code is governed by a BSD-style
|
// license that can be found in the LICENSE file.
|
|
`)
|
out.Write(src)
|
|
const target = "zfuncversion.go"
|
if err := ioutil.WriteFile(target, out.Bytes(), 0644); err != nil {
|
log.Fatal(err)
|
}
|
}
|
|
type visitFunc func(ast.Node) ast.Visitor
|
|
func (f visitFunc) Visit(n ast.Node) ast.Visitor { return f(n) }
|
|
func rewriteCalls(n ast.Node) ast.Visitor {
|
ce, ok := n.(*ast.CallExpr)
|
if ok {
|
rewriteCall(ce)
|
}
|
return visitFunc(rewriteCalls)
|
}
|
|
func rewriteCall(ce *ast.CallExpr) {
|
ident, ok := ce.Fun.(*ast.Ident)
|
if !ok {
|
// e.g. skip SelectorExpr (data.Less(..) calls)
|
return
|
}
|
// skip casts
|
if ident.Name == "int" || ident.Name == "uint" {
|
return
|
}
|
if len(ce.Args) < 1 {
|
return
|
}
|
ident.Name += "_func"
|
}
|
