mirror of
https://github.com/golang/go
synced 2024-11-18 19:14:40 -07:00
132 lines
3.3 KiB
Go
132 lines
3.3 KiB
Go
// Copyright 2013 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 importer
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// This file defines various utility functions exposed by the package
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// and used by it.
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import (
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"errors"
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"go/ast"
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"go/build"
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"go/parser"
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"go/token"
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"os"
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"path/filepath"
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"strings"
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)
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// CreatePackageFromArgs builds an initial Package from a list of
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// command-line arguments.
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// If args is a list of *.go files, they are parsed and type-checked.
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// If args is a Go package import path, that package is imported.
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// The rest result contains the suffix of args that were not consumed.
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//
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// This utility is provided to facilitate construction of command-line
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// tools with a consistent user interface.
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//
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func CreatePackageFromArgs(imp *Importer, args []string) (info *PackageInfo, rest []string, err error) {
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switch {
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case len(args) == 0:
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return nil, nil, errors.New("No *.go source files nor package name was specified.")
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case strings.HasSuffix(args[0], ".go"):
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// % tool a.go b.go ...
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// Leading consecutive *.go arguments constitute main package.
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i := 1
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for ; i < len(args) && strings.HasSuffix(args[i], ".go"); i++ {
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}
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var files []*ast.File
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files, err = ParseFiles(imp.Fset, ".", args[:i]...)
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rest = args[i:]
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if err == nil {
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info = imp.CreateSourcePackage("main", files)
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err = info.Err
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}
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default:
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// % tool my/package ...
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// First argument is import path of main package.
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pkgname := args[0]
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info, err = imp.LoadPackage(pkgname)
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rest = args[1:]
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}
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return
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}
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// MakeGoBuildLoader returns an implementation of the SourceLoader
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// function prototype that locates packages using the go/build
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// libraries. It may return nil upon gross misconfiguration
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// (e.g. os.Getwd() failed).
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//
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// ctxt specifies the go/build.Context to use; if nil, the default
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// Context is used.
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//
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func MakeGoBuildLoader(ctxt *build.Context) SourceLoader {
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srcDir, err := os.Getwd()
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if err != nil {
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return nil // serious misconfiguration
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}
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if ctxt == nil {
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ctxt = &build.Default
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}
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return func(fset *token.FileSet, path string) (files []*ast.File, err error) {
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// TODO(adonovan): fix: Do we need cwd? Shouldn't
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// ImportDir(path) / $GOROOT suffice?
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bp, err := ctxt.Import(path, srcDir, 0)
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if _, ok := err.(*build.NoGoError); ok {
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return nil, nil // empty directory
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}
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if err != nil {
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return // import failed
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}
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files, err = ParseFiles(fset, bp.Dir, bp.GoFiles...)
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if err != nil {
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return nil, err
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}
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return
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}
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}
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// ParseFiles parses the Go source files files within directory dir
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// and returns their ASTs, or the first parse error if any.
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//
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// This utility function is provided to facilitate implementing a
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// SourceLoader.
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//
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func ParseFiles(fset *token.FileSet, dir string, files ...string) (parsed []*ast.File, err error) {
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for _, file := range files {
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var f *ast.File
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if !filepath.IsAbs(file) {
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file = filepath.Join(dir, file)
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}
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f, err = parser.ParseFile(fset, file, nil, parser.DeclarationErrors)
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if err != nil {
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return // parsing failed
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}
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parsed = append(parsed, f)
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}
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return
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}
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// ---------- Internal helpers ----------
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// unparen returns e with any enclosing parentheses stripped.
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func unparen(e ast.Expr) ast.Expr {
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for {
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p, ok := e.(*ast.ParenExpr)
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if !ok {
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break
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}
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e = p.X
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}
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return e
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}
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func unreachable() {
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panic("unreachable")
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}
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