| // Copyright 2015 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 main |
| |
| import ( |
| "go/build" |
| "os" |
| "path" |
| "path/filepath" |
| "strings" |
| ) |
| |
| // Dirs is a structure for scanning the directory tree. |
| // Its Next method returns the next Go source directory it finds. |
| // Although it can be used to scan the tree multiple times, it |
| // only walks the tree once, caching the data it finds. |
| type Dirs struct { |
| scan chan string // directories generated by walk. |
| paths []string // Cache of known paths. |
| offset int // Counter for Next. |
| } |
| |
| var dirs Dirs |
| |
| func init() { |
| dirs.paths = make([]string, 0, 1000) |
| dirs.scan = make(chan string) |
| go dirs.walk() |
| } |
| |
| // Reset puts the scan back at the beginning. |
| func (d *Dirs) Reset() { |
| d.offset = 0 |
| } |
| |
| // Next returns the next directory in the scan. The boolean |
| // is false when the scan is done. |
| func (d *Dirs) Next() (string, bool) { |
| if d.offset < len(d.paths) { |
| path := d.paths[d.offset] |
| d.offset++ |
| return path, true |
| } |
| path, ok := <-d.scan |
| if !ok { |
| return "", false |
| } |
| d.paths = append(d.paths, path) |
| d.offset++ |
| return path, ok |
| } |
| |
| // walk walks the trees in GOROOT and GOPATH. |
| func (d *Dirs) walk() { |
| d.walkRoot(build.Default.GOROOT) |
| for _, root := range splitGopath() { |
| d.walkRoot(root) |
| } |
| close(d.scan) |
| } |
| |
| // walkRoot walks a single directory. Each Go source directory it finds is |
| // delivered on d.scan. |
| func (d *Dirs) walkRoot(root string) { |
| root = path.Join(root, "src") |
| slashDot := string(filepath.Separator) + "." |
| // We put a slash on the pkg so can use simple string comparison below |
| // yet avoid inadvertent matches, like /foobar matching bar. |
| |
| visit := func(pathName string, f os.FileInfo, err error) error { |
| if err != nil { |
| return nil |
| } |
| // One package per directory. Ignore the files themselves. |
| if !f.IsDir() { |
| return nil |
| } |
| // No .git or other dot nonsense please. |
| if strings.Contains(pathName, slashDot) { |
| return filepath.SkipDir |
| } |
| // Does the directory contain any Go files? If so, it's a candidate. |
| if hasGoFiles(pathName) { |
| d.scan <- pathName |
| return nil |
| } |
| return nil |
| } |
| |
| filepath.Walk(root, visit) |
| } |
| |
| // hasGoFiles tests whether the directory contains at least one file with ".go" |
| // extension |
| func hasGoFiles(path string) bool { |
| dir, err := os.Open(path) |
| if err != nil { |
| // ignore unreadable directories |
| return false |
| } |
| defer dir.Close() |
| |
| names, err := dir.Readdirnames(0) |
| if err != nil { |
| // ignore unreadable directories |
| return false |
| } |
| |
| for _, name := range names { |
| if strings.HasSuffix(name, ".go") { |
| return true |
| } |
| } |
| |
| return false |
| } |