Extract go_merge into its own package

This change is needed to support building gvisor for Fuchsia, which uses
Chromium's GN build system; at the time of writing, Fuchsia's Go support
does not include explicit enumeration of files, assuming instead that Go
binaries are always built from all Go source files in a given package.
Rather than extending Fuchsia's Go support, it is easier simply to
extract a separate package here.

PiperOrigin-RevId: 227133402
Change-Id: I1c64fff286d9c014b4bd1183b76023b35b60c720

1 files changed, 0 insertions, 139 deletions

diff --git a/tools/go_generics/merge.go b/tools/go_generics/merge.go
deleted file mode 100644
index 2f83facf8..000000000
--- a/tools/go_generics/merge.go
+++ /dev/null
@@ -1,139 +0,0 @@
-// Copyright 2018 Google LLC
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package main
-
-import (
-	"bytes"
-	"flag"
-	"fmt"
-	"go/ast"
-	"go/format"
-	"go/parser"
-	"go/token"
-	"io/ioutil"
-	"os"
-	"path/filepath"
-	"strconv"
-)
-
-var (
-	output = flag.String("o", "", "output `file`")
-)
-
-func fatalf(s string, args ...interface{}) {
-	fmt.Fprintf(os.Stderr, s, args...)
-	os.Exit(1)
-}
-
-func main() {
-	flag.Usage = func() {
-		fmt.Fprintf(os.Stderr, "Usage: %s [options] <input1> [<input2> ...]\n", os.Args[0])
-		flag.PrintDefaults()
-	}
-
-	flag.Parse()
-	if *output == "" || len(flag.Args()) == 0 {
-		flag.Usage()
-		os.Exit(1)
-	}
-
-	// Load all files.
-	files := make(map[string]*ast.File)
-	fset := token.NewFileSet()
-	var name string
-	for _, fname := range flag.Args() {
-		f, err := parser.ParseFile(fset, fname, nil, parser.ParseComments|parser.DeclarationErrors|parser.SpuriousErrors)
-		if err != nil {
-			fatalf("%v\n", err)
-		}
-
-		files[fname] = f
-		if name == "" {
-			name = f.Name.Name
-		} else if name != f.Name.Name {
-			fatalf("Expected '%s' for package name instead of '%s'.\n", name, f.Name.Name)
-		}
-	}
-
-	// Merge all files into one.
-	pkg := &ast.Package{
-		Name:  name,
-		Files: files,
-	}
-	f := ast.MergePackageFiles(pkg, ast.FilterUnassociatedComments|ast.FilterFuncDuplicates|ast.FilterImportDuplicates)
-
-	// Create a new declaration slice with all imports at the top, merging any
-	// redundant imports.
-	imports := make(map[string]*ast.ImportSpec)
-	var anonImports []*ast.ImportSpec
-	for _, d := range f.Decls {
-		if g, ok := d.(*ast.GenDecl); ok && g.Tok == token.IMPORT {
-			for _, s := range g.Specs {
-				i := s.(*ast.ImportSpec)
-				p, _ := strconv.Unquote(i.Path.Value)
-				var n string
-				if i.Name == nil {
-					n = filepath.Base(p)
-				} else {
-					n = i.Name.Name
-				}
-				if n == "_" {
-					anonImports = append(anonImports, i)
-				} else {
-					if i2, ok := imports[n]; ok {
-						if first, second := i.Path.Value, i2.Path.Value; first != second {
-							fatalf("Conflicting paths for import name '%s': '%s' vs. '%s'\n", n, first, second)
-						}
-					} else {
-						imports[n] = i
-					}
-				}
-			}
-		}
-	}
-	newDecls := make([]ast.Decl, 0, len(f.Decls))
-	if l := len(imports) + len(anonImports); l > 0 {
-		// Non-NoPos Lparen is needed for Go to recognize more than one spec in
-		// ast.GenDecl.Specs.
-		d := &ast.GenDecl{
-			Tok:    token.IMPORT,
-			Lparen: token.NoPos + 1,
-			Specs:  make([]ast.Spec, 0, l),
-		}
-		for _, i := range imports {
-			d.Specs = append(d.Specs, i)
-		}
-		for _, i := range anonImports {
-			d.Specs = append(d.Specs, i)
-		}
-		newDecls = append(newDecls, d)
-	}
-	for _, d := range f.Decls {
-		if g, ok := d.(*ast.GenDecl); !ok || g.Tok != token.IMPORT {
-			newDecls = append(newDecls, d)
-		}
-	}
-	f.Decls = newDecls
-
-	// Write the output file.
-	var buf bytes.Buffer
-	if err := format.Node(&buf, fset, f); err != nil {
-		fatalf("%v\n", err)
-	}
-
-	if err := ioutil.WriteFile(*output, buf.Bytes(), 0644); err != nil {
-		fatalf("%v\n", err)
-	}
-}