140 lines
3.4 KiB
Go
140 lines
3.4 KiB
Go
// Copyright 2018 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package main
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import (
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"bytes"
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"flag"
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"fmt"
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"go/ast"
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"go/format"
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"go/parser"
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"go/token"
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"io/ioutil"
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"os"
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"path/filepath"
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"strconv"
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)
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var (
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output = flag.String("o", "", "output `file`")
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)
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func fatalf(s string, args ...interface{}) {
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fmt.Fprintf(os.Stderr, s, args...)
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os.Exit(1)
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}
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func main() {
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flag.Usage = func() {
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fmt.Fprintf(os.Stderr, "Usage: %s [options] <input1> [<input2> ...]\n", os.Args[0])
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flag.PrintDefaults()
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}
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flag.Parse()
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if *output == "" || len(flag.Args()) == 0 {
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flag.Usage()
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os.Exit(1)
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}
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// Load all files.
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files := make(map[string]*ast.File)
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fset := token.NewFileSet()
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var name string
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for _, fname := range flag.Args() {
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f, err := parser.ParseFile(fset, fname, nil, parser.ParseComments|parser.DeclarationErrors|parser.SpuriousErrors)
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if err != nil {
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fatalf("%v\n", err)
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}
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files[fname] = f
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if name == "" {
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name = f.Name.Name
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} else if name != f.Name.Name {
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fatalf("Expected '%s' for package name instead of '%s'.\n", name, f.Name.Name)
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}
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}
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// Merge all files into one.
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pkg := &ast.Package{
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Name: name,
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Files: files,
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}
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f := ast.MergePackageFiles(pkg, ast.FilterUnassociatedComments|ast.FilterFuncDuplicates|ast.FilterImportDuplicates)
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// Create a new declaration slice with all imports at the top, merging any
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// redundant imports.
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imports := make(map[string]*ast.ImportSpec)
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var anonImports []*ast.ImportSpec
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for _, d := range f.Decls {
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if g, ok := d.(*ast.GenDecl); ok && g.Tok == token.IMPORT {
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for _, s := range g.Specs {
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i := s.(*ast.ImportSpec)
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p, _ := strconv.Unquote(i.Path.Value)
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var n string
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if i.Name == nil {
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n = filepath.Base(p)
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} else {
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n = i.Name.Name
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}
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if n == "_" {
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anonImports = append(anonImports, i)
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} else {
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if i2, ok := imports[n]; ok {
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if first, second := i.Path.Value, i2.Path.Value; first != second {
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fatalf("Conflicting paths for import name '%s': '%s' vs. '%s'\n", n, first, second)
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}
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} else {
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imports[n] = i
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}
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}
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}
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}
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}
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newDecls := make([]ast.Decl, 0, len(f.Decls))
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if l := len(imports) + len(anonImports); l > 0 {
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// Non-NoPos Lparen is needed for Go to recognize more than one spec in
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// ast.GenDecl.Specs.
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d := &ast.GenDecl{
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Tok: token.IMPORT,
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Lparen: token.NoPos + 1,
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Specs: make([]ast.Spec, 0, l),
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}
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for _, i := range imports {
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d.Specs = append(d.Specs, i)
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}
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for _, i := range anonImports {
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d.Specs = append(d.Specs, i)
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}
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newDecls = append(newDecls, d)
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}
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for _, d := range f.Decls {
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if g, ok := d.(*ast.GenDecl); !ok || g.Tok != token.IMPORT {
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newDecls = append(newDecls, d)
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}
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}
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f.Decls = newDecls
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// Write the output file.
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var buf bytes.Buffer
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if err := format.Node(&buf, fset, f); err != nil {
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fatalf("%v\n", err)
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}
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if err := ioutil.WriteFile(*output, buf.Bytes(), 0644); err != nil {
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fatalf("%v\n", err)
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}
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}
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