webp: make a placeholder package for Go 1.5 and earlier.

This lets programs that underscore import this package build on Go 1.5.

Change-Id: Icd977b16eb44389f8ee4640c2ab57e4b6791b1f4
Reviewed-on: https://go-review.googlesource.com/24954
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This commit is contained in:
Nigel Tao 2016-07-16 09:11:08 +10:00
parent 81315f0c68
commit c348254d65
2 changed files with 31 additions and 5 deletions

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@ -4,11 +4,7 @@
// +build go1.6 // +build go1.6
// Package webp implements a decoder for WEBP images. package webp
//
// WEBP is defined at:
// https://developers.google.com/speed/webp/docs/riff_container
package webp // import "golang.org/x/image/webp"
import ( import (
"bytes" "bytes"

30
webp/webp.go Normal file
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@ -0,0 +1,30 @@
// 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 webp implements a decoder for WEBP images.
//
// WEBP is defined at:
// https://developers.google.com/speed/webp/docs/riff_container
//
// It requires Go 1.6 or later.
package webp // import "golang.org/x/image/webp"
// This blank Go file, other than the package clause, exists so that this
// package can be built for Go 1.5 and earlier. (The other files in this
// package are all marked "+build go1.6" for the NYCbCrA types introduced in Go
// 1.6). There is no functionality in a blank package, but some image
// manipulation programs might still underscore import this package for the
// side effect of registering the WEBP format with the standard library's
// image.RegisterFormat and image.Decode functions. For example, that program
// might contain:
//
// // Underscore imports to register some formats for image.Decode.
// import _ "image/gif"
// import _ "image/jpeg"
// import _ "image/png"
// import _ "golang.org/x/image/webp"
//
// Such a program will still compile for Go 1.5 (due to this placeholder Go
// file). It will simply not be able to recognize and decode WEBP (but still
// handle GIF, JPEG and PNG).