| // 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" |
| "log" |
| "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.bfsWalkRoot(build.Default.GOROOT) |
| for _, root := range splitGopath() { |
| d.bfsWalkRoot(root) |
| } |
| close(d.scan) |
| } |
| |
| // bfsWalkRoot walks a single directory hierarchy in breadth-first lexical order. |
| // Each Go source directory it finds is delivered on d.scan. |
| func (d *Dirs) bfsWalkRoot(root string) { |
| root = path.Join(root, "src") |
| |
| // this is the queue of directories to examine in this pass. |
| this := []string{} |
| // next is the queue of directories to examine in the next pass. |
| next := []string{root} |
| |
| for len(next) > 0 { |
| this, next = next, this[0:0] |
| for _, dir := range this { |
| fd, err := os.Open(dir) |
| if err != nil { |
| log.Printf("error opening %s: %v", dir, err) |
| return // TODO? There may be entry before the error. |
| } |
| entries, err := fd.Readdir(0) |
| fd.Close() |
| if err != nil { |
| log.Printf("error reading %s: %v", dir, err) |
| return // TODO? There may be entry before the error. |
| } |
| hasGoFiles := false |
| for _, entry := range entries { |
| name := entry.Name() |
| // For plain files, remember if this directory contains any .go |
| // source files, but ignore them otherwise. |
| if !entry.IsDir() { |
| if !hasGoFiles && strings.HasSuffix(name, ".go") { |
| hasGoFiles = true |
| } |
| continue |
| } |
| // Entry is a directory. |
| // No .git or other dot nonsense please. |
| if strings.HasPrefix(name, ".") { |
| continue |
| } |
| // Remember this (fully qualified) directory for the next pass. |
| next = append(next, filepath.Join(dir, name)) |
| } |
| if hasGoFiles { |
| // It's a candidate. |
| d.scan <- dir |
| } |
| } |
| |
| } |
| } |