90 lines
1.8 KiB
Go
90 lines
1.8 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 gatefs provides an implementation of the FileSystem
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// interface that wraps another FileSystem and limits its concurrency.
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package gatefs // import "golang.org/x/tools/godoc/vfs/gatefs"
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import (
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"fmt"
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"os"
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"golang.org/x/tools/godoc/vfs"
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)
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// New returns a new FileSystem that delegates to fs.
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// If gateCh is non-nil and buffered, it's used as a gate
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// to limit concurrency on calls to fs.
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func New(fs vfs.FileSystem, gateCh chan bool) vfs.FileSystem {
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if cap(gateCh) == 0 {
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return fs
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}
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return gatefs{fs, gate(gateCh)}
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}
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type gate chan bool
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func (g gate) enter() { g <- true }
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func (g gate) leave() { <-g }
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type gatefs struct {
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fs vfs.FileSystem
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gate
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}
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func (fs gatefs) String() string {
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return fmt.Sprintf("gated(%s, %d)", fs.fs.String(), cap(fs.gate))
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}
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func (fs gatefs) Open(p string) (vfs.ReadSeekCloser, error) {
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fs.enter()
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defer fs.leave()
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rsc, err := fs.fs.Open(p)
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if err != nil {
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return nil, err
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}
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return gatef{rsc, fs.gate}, nil
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}
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func (fs gatefs) Lstat(p string) (os.FileInfo, error) {
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fs.enter()
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defer fs.leave()
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return fs.fs.Lstat(p)
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}
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func (fs gatefs) Stat(p string) (os.FileInfo, error) {
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fs.enter()
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defer fs.leave()
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return fs.fs.Stat(p)
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}
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func (fs gatefs) ReadDir(p string) ([]os.FileInfo, error) {
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fs.enter()
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defer fs.leave()
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return fs.fs.ReadDir(p)
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}
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type gatef struct {
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rsc vfs.ReadSeekCloser
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gate
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}
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func (f gatef) Read(p []byte) (n int, err error) {
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f.enter()
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defer f.leave()
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return f.rsc.Read(p)
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}
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func (f gatef) Seek(offset int64, whence int) (ret int64, err error) {
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f.enter()
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defer f.leave()
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return f.rsc.Seek(offset, whence)
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}
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func (f gatef) Close() error {
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f.enter()
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defer f.leave()
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return f.rsc.Close()
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}
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