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https://github.com/golang/go
synced 2024-11-05 19:46:11 -07:00
9ac8940d29
Phrases like "returns whether or not the image is opaque" could be describing what the function does (it always returns, regardless of the opacity) or what it returns (a boolean indicating the opacity). Even when the "or not" is missing, the phrasing is bizarre. Go with "reports whether", which is still clunky but at least makes it clear we're talking about the return value. R=golang-dev, dsymonds CC=golang-dev https://golang.org/cl/11458046
90 lines
2.2 KiB
Go
90 lines
2.2 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 util contains utility types and functions for godoc.
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package util
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import (
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pathpkg "path"
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"sync"
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"time"
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"unicode/utf8"
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"code.google.com/p/go.tools/godoc/vfs"
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)
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// An RWValue wraps a value and permits mutually exclusive
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// access to it and records the time the value was last set.
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type RWValue struct {
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mutex sync.RWMutex
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value interface{}
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timestamp time.Time // time of last set()
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}
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func (v *RWValue) Set(value interface{}) {
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v.mutex.Lock()
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v.value = value
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v.timestamp = time.Now()
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v.mutex.Unlock()
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}
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func (v *RWValue) Get() (interface{}, time.Time) {
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v.mutex.RLock()
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defer v.mutex.RUnlock()
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return v.value, v.timestamp
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}
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// IsText reports whether a significant prefix of s looks like correct UTF-8;
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// that is, if it is likely that s is human-readable text.
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func IsText(s []byte) bool {
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const max = 1024 // at least utf8.UTFMax
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if len(s) > max {
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s = s[0:max]
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}
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for i, c := range string(s) {
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if i+utf8.UTFMax > len(s) {
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// last char may be incomplete - ignore
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break
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}
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if c == 0xFFFD || c < ' ' && c != '\n' && c != '\t' && c != '\f' {
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// decoding error or control character - not a text file
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return false
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}
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}
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return true
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}
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// textExt[x] is true if the extension x indicates a text file, and false otherwise.
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var textExt = map[string]bool{
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".css": false, // must be served raw
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".js": false, // must be served raw
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}
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// IsTextFile reports whether the file has a known extension indicating
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// a text file, or if a significant chunk of the specified file looks like
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// correct UTF-8; that is, if it is likely that the file contains human-
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// readable text.
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func IsTextFile(fs vfs.Opener, filename string) bool {
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// if the extension is known, use it for decision making
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if isText, found := textExt[pathpkg.Ext(filename)]; found {
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return isText
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}
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// the extension is not known; read an initial chunk
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// of the file and check if it looks like text
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f, err := fs.Open(filename)
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if err != nil {
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return false
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}
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defer f.Close()
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var buf [1024]byte
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n, err := f.Read(buf[0:])
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if err != nil {
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return false
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}
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return IsText(buf[0:n])
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}
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