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Diffstat (limited to 'vendor/golang.org/x/tools/internal/fastwalk/fastwalk.go')
| -rw-r--r-- | vendor/golang.org/x/tools/internal/fastwalk/fastwalk.go | 196 |
1 files changed, 0 insertions, 196 deletions
diff --git a/vendor/golang.org/x/tools/internal/fastwalk/fastwalk.go b/vendor/golang.org/x/tools/internal/fastwalk/fastwalk.go deleted file mode 100644 index 7219c8e9..00000000 --- a/vendor/golang.org/x/tools/internal/fastwalk/fastwalk.go +++ /dev/null @@ -1,196 +0,0 @@ -// Copyright 2016 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 fastwalk provides a faster version of filepath.Walk for file system -// scanning tools. -package fastwalk - -import ( - "errors" - "os" - "path/filepath" - "runtime" - "sync" -) - -// TraverseLink is used as a return value from WalkFuncs to indicate that the -// symlink named in the call may be traversed. -var TraverseLink = errors.New("fastwalk: traverse symlink, assuming target is a directory") - -// SkipFiles is a used as a return value from WalkFuncs to indicate that the -// callback should not be called for any other files in the current directory. -// Child directories will still be traversed. -var SkipFiles = errors.New("fastwalk: skip remaining files in directory") - -// Walk is a faster implementation of filepath.Walk. -// -// filepath.Walk's design necessarily calls os.Lstat on each file, -// even if the caller needs less info. -// Many tools need only the type of each file. -// On some platforms, this information is provided directly by the readdir -// system call, avoiding the need to stat each file individually. -// fastwalk_unix.go contains a fork of the syscall routines. -// -// See golang.org/issue/16399 -// -// Walk walks the file tree rooted at root, calling walkFn for -// each file or directory in the tree, including root. -// -// If fastWalk returns filepath.SkipDir, the directory is skipped. -// -// Unlike filepath.Walk: -// * file stat calls must be done by the user. -// The only provided metadata is the file type, which does not include -// any permission bits. -// * multiple goroutines stat the filesystem concurrently. The provided -// walkFn must be safe for concurrent use. -// * fastWalk can follow symlinks if walkFn returns the TraverseLink -// sentinel error. It is the walkFn's responsibility to prevent -// fastWalk from going into symlink cycles. -func Walk(root string, walkFn func(path string, typ os.FileMode) error) error { - // TODO(bradfitz): make numWorkers configurable? We used a - // minimum of 4 to give the kernel more info about multiple - // things we want, in hopes its I/O scheduling can take - // advantage of that. Hopefully most are in cache. Maybe 4 is - // even too low of a minimum. Profile more. - numWorkers := 4 - if n := runtime.NumCPU(); n > numWorkers { - numWorkers = n - } - - // Make sure to wait for all workers to finish, otherwise - // walkFn could still be called after returning. This Wait call - // runs after close(e.donec) below. - var wg sync.WaitGroup - defer wg.Wait() - - w := &walker{ - fn: walkFn, - enqueuec: make(chan walkItem, numWorkers), // buffered for performance - workc: make(chan walkItem, numWorkers), // buffered for performance - donec: make(chan struct{}), - - // buffered for correctness & not leaking goroutines: - resc: make(chan error, numWorkers), - } - defer close(w.donec) - - for i := 0; i < numWorkers; i++ { - wg.Add(1) - go w.doWork(&wg) - } - todo := []walkItem{{dir: root}} - out := 0 - for { - workc := w.workc - var workItem walkItem - if len(todo) == 0 { - workc = nil - } else { - workItem = todo[len(todo)-1] - } - select { - case workc <- workItem: - todo = todo[:len(todo)-1] - out++ - case it := <-w.enqueuec: - todo = append(todo, it) - case err := <-w.resc: - out-- - if err != nil { - return err - } - if out == 0 && len(todo) == 0 { - // It's safe to quit here, as long as the buffered - // enqueue channel isn't also readable, which might - // happen if the worker sends both another unit of - // work and its result before the other select was - // scheduled and both w.resc and w.enqueuec were - // readable. - select { - case it := <-w.enqueuec: - todo = append(todo, it) - default: - return nil - } - } - } - } -} - -// doWork reads directories as instructed (via workc) and runs the -// user's callback function. -func (w *walker) doWork(wg *sync.WaitGroup) { - defer wg.Done() - for { - select { - case <-w.donec: - return - case it := <-w.workc: - select { - case <-w.donec: - return - case w.resc <- w.walk(it.dir, !it.callbackDone): - } - } - } -} - -type walker struct { - fn func(path string, typ os.FileMode) error - - donec chan struct{} // closed on fastWalk's return - workc chan walkItem // to workers - enqueuec chan walkItem // from workers - resc chan error // from workers -} - -type walkItem struct { - dir string - callbackDone bool // callback already called; don't do it again -} - -func (w *walker) enqueue(it walkItem) { - select { - case w.enqueuec <- it: - case <-w.donec: - } -} - -func (w *walker) onDirEnt(dirName, baseName string, typ os.FileMode) error { - joined := dirName + string(os.PathSeparator) + baseName - if typ == os.ModeDir { - w.enqueue(walkItem{dir: joined}) - return nil - } - - err := w.fn(joined, typ) - if typ == os.ModeSymlink { - if err == TraverseLink { - // Set callbackDone so we don't call it twice for both the - // symlink-as-symlink and the symlink-as-directory later: - w.enqueue(walkItem{dir: joined, callbackDone: true}) - return nil - } - if err == filepath.SkipDir { - // Permit SkipDir on symlinks too. - return nil - } - } - return err -} - -func (w *walker) walk(root string, runUserCallback bool) error { - if runUserCallback { - err := w.fn(root, os.ModeDir) - if err == filepath.SkipDir { - return nil - } - if err != nil { - return err - } - } - - return readDir(root, w.onDirEnt) -} |