| 1 | // Copyright 2013 The Go Authors. All rights reserved. |
|---|---|
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | // Package gatefs provides an implementation of the FileSystem |
| 6 | // interface that wraps another FileSystem and limits its concurrency. |
| 7 | package gatefs // import "golang.org/x/tools/godoc/vfs/gatefs" |
| 8 | |
| 9 | import ( |
| 10 | "fmt" |
| 11 | "os" |
| 12 | |
| 13 | "golang.org/x/tools/godoc/vfs" |
| 14 | ) |
| 15 | |
| 16 | // New returns a new FileSystem that delegates to fs. |
| 17 | // If gateCh is non-nil and buffered, it's used as a gate |
| 18 | // to limit concurrency on calls to fs. |
| 19 | func New(fs vfs.FileSystem, gateCh chan bool) vfs.FileSystem { |
| 20 | if cap(gateCh) == 0 { |
| 21 | return fs |
| 22 | } |
| 23 | return gatefs{fs, gate(gateCh)} |
| 24 | } |
| 25 | |
| 26 | type gate chan bool |
| 27 | |
| 28 | func (g gate) enter() { g <- true } |
| 29 | func (g gate) leave() { <-g } |
| 30 | |
| 31 | type gatefs struct { |
| 32 | fs vfs.FileSystem |
| 33 | gate |
| 34 | } |
| 35 | |
| 36 | func (fs gatefs) String() string { |
| 37 | return fmt.Sprintf("gated(%s, %d)", fs.fs.String(), cap(fs.gate)) |
| 38 | } |
| 39 | |
| 40 | func (fs gatefs) RootType(path string) vfs.RootType { |
| 41 | return fs.fs.RootType(path) |
| 42 | } |
| 43 | |
| 44 | func (fs gatefs) Open(p string) (vfs.ReadSeekCloser, error) { |
| 45 | fs.enter() |
| 46 | defer fs.leave() |
| 47 | rsc, err := fs.fs.Open(p) |
| 48 | if err != nil { |
| 49 | return nil, err |
| 50 | } |
| 51 | return gatef{rsc, fs.gate}, nil |
| 52 | } |
| 53 | |
| 54 | func (fs gatefs) Lstat(p string) (os.FileInfo, error) { |
| 55 | fs.enter() |
| 56 | defer fs.leave() |
| 57 | return fs.fs.Lstat(p) |
| 58 | } |
| 59 | |
| 60 | func (fs gatefs) Stat(p string) (os.FileInfo, error) { |
| 61 | fs.enter() |
| 62 | defer fs.leave() |
| 63 | return fs.fs.Stat(p) |
| 64 | } |
| 65 | |
| 66 | func (fs gatefs) ReadDir(p string) ([]os.FileInfo, error) { |
| 67 | fs.enter() |
| 68 | defer fs.leave() |
| 69 | return fs.fs.ReadDir(p) |
| 70 | } |
| 71 | |
| 72 | type gatef struct { |
| 73 | rsc vfs.ReadSeekCloser |
| 74 | gate |
| 75 | } |
| 76 | |
| 77 | func (f gatef) Read(p []byte) (n int, err error) { |
| 78 | f.enter() |
| 79 | defer f.leave() |
| 80 | return f.rsc.Read(p) |
| 81 | } |
| 82 | |
| 83 | func (f gatef) Seek(offset int64, whence int) (ret int64, err error) { |
| 84 | f.enter() |
| 85 | defer f.leave() |
| 86 | return f.rsc.Seek(offset, whence) |
| 87 | } |
| 88 | |
| 89 | func (f gatef) Close() error { |
| 90 | f.enter() |
| 91 | defer f.leave() |
| 92 | return f.rsc.Close() |
| 93 | } |
| 94 |
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