wide/vendor/golang.org/x/tools/go/buildutil/allpackages.go

124 lines
3.0 KiB
Go

// Copyright 2014 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.
// Package buildutil provides utilities related to the go/build
// package in the standard library.
//
// All I/O is done via the build.Context file system interface, which must
// be concurrency-safe.
package buildutil // import "golang.org/x/tools/go/buildutil"
import (
"go/build"
"os"
"path/filepath"
"sort"
"strings"
"sync"
)
// AllPackages returns the import path of each Go package in any source
// directory of the specified build context (e.g. $GOROOT or an element
// of $GOPATH). Errors are ignored. The results are sorted.
//
// The result may include import paths for directories that contain no
// *.go files, such as "archive" (in $GOROOT/src).
//
// All I/O is done via the build.Context file system interface,
// which must be concurrency-safe.
//
func AllPackages(ctxt *build.Context) []string {
var list []string
ForEachPackage(ctxt, func(pkg string, _ error) {
list = append(list, pkg)
})
sort.Strings(list)
return list
}
// ForEachPackage calls the found function with the import path of
// each Go package it finds in any source directory of the specified
// build context (e.g. $GOROOT or an element of $GOPATH).
//
// If the package directory exists but could not be read, the second
// argument to the found function provides the error.
//
// All I/O is done via the build.Context file system interface,
// which must be concurrency-safe.
//
func ForEachPackage(ctxt *build.Context, found func(importPath string, err error)) {
// We use a counting semaphore to limit
// the number of parallel calls to ReadDir.
sema := make(chan bool, 20)
ch := make(chan item)
var wg sync.WaitGroup
for _, root := range ctxt.SrcDirs() {
root := root
wg.Add(1)
go func() {
allPackages(ctxt, sema, root, ch)
wg.Done()
}()
}
go func() {
wg.Wait()
close(ch)
}()
// All calls to found occur in the caller's goroutine.
for i := range ch {
found(i.importPath, i.err)
}
}
type item struct {
importPath string
err error // (optional)
}
func allPackages(ctxt *build.Context, sema chan bool, root string, ch chan<- item) {
root = filepath.Clean(root) + string(os.PathSeparator)
var wg sync.WaitGroup
var walkDir func(dir string)
walkDir = func(dir string) {
// Avoid .foo, _foo, and testdata directory trees.
base := filepath.Base(dir)
if base == "" || base[0] == '.' || base[0] == '_' || base == "testdata" {
return
}
pkg := filepath.ToSlash(strings.TrimPrefix(dir, root))
// Prune search if we encounter any of these import paths.
switch pkg {
case "builtin":
return
}
sema <- true
files, err := ReadDir(ctxt, dir)
<-sema
if pkg != "" || err != nil {
ch <- item{pkg, err}
}
for _, fi := range files {
fi := fi
if fi.IsDir() {
wg.Add(1)
go func() {
walkDir(filepath.Join(dir, fi.Name()))
wg.Done()
}()
}
}
}
walkDir(root)
wg.Wait()
}