Fix WebP detection in some cases

Gopkg.lock

@@ -356,14 +356,13 @@
 
 [[projects]]
   branch = "master"
-  digest = "1:45cffd5d7beb358f820cf86c094126bb55d9e3f022bc2fe429086742aa70d620"
+  digest = "1:70fb374148272deb5d48b47ea8b05dc6bbe31861eb0218ede9b6c67a30b7142a"
   name = "golang.org/x/image"
   packages = [
     "bmp",
     "riff",
     "vp8",
     "vp8l",
-    "webp",
   ]
   pruneopts = "NUT"
   revision = "cd38e8056d9b27bb2f265effa37fb0ea6b8a7f0f"
@@ -555,7 +554,6 @@
     "golang.org/x/image/riff",
     "golang.org/x/image/vp8",
     "golang.org/x/image/vp8l",
-    "golang.org/x/image/webp",
     "golang.org/x/net/netutil",
     "golang.org/x/sync/errgroup",
     "google.golang.org/api/option",

download.go

@@ -17,7 +17,6 @@ import (
 	_ "image/png"
 
 	_ "github.com/mat/besticon/ico"
-	_ "golang.org/x/image/webp"
 )
 
 var (

vendor/golang.org/x/image/webp/decode.go

@@ -1,270 +0,0 @@
-// Copyright 2011 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
-
-import (
-	"bytes"
-	"errors"
-	"image"
-	"image/color"
-	"io"
-
-	"golang.org/x/image/riff"
-	"golang.org/x/image/vp8"
-	"golang.org/x/image/vp8l"
-)
-
-var errInvalidFormat = errors.New("webp: invalid format")
-
-var (
-	fccALPH = riff.FourCC{'A', 'L', 'P', 'H'}
-	fccVP8  = riff.FourCC{'V', 'P', '8', ' '}
-	fccVP8L = riff.FourCC{'V', 'P', '8', 'L'}
-	fccVP8X = riff.FourCC{'V', 'P', '8', 'X'}
-	fccWEBP = riff.FourCC{'W', 'E', 'B', 'P'}
-)
-
-func decode(r io.Reader, configOnly bool) (image.Image, image.Config, error) {
-	formType, riffReader, err := riff.NewReader(r)
-	if err != nil {
-		return nil, image.Config{}, err
-	}
-	if formType != fccWEBP {
-		return nil, image.Config{}, errInvalidFormat
-	}
-
-	var (
-		alpha          []byte
-		alphaStride    int
-		wantAlpha      bool
-		widthMinusOne  uint32
-		heightMinusOne uint32
-		buf            [10]byte
-	)
-	for {
-		chunkID, chunkLen, chunkData, err := riffReader.Next()
-		if err == io.EOF {
-			err = errInvalidFormat
-		}
-		if err != nil {
-			return nil, image.Config{}, err
-		}
-
-		switch chunkID {
-		case fccALPH:
-			if !wantAlpha {
-				return nil, image.Config{}, errInvalidFormat
-			}
-			wantAlpha = false
-			// Read the Pre-processing | Filter | Compression byte.
-			if _, err := io.ReadFull(chunkData, buf[:1]); err != nil {
-				if err == io.EOF {
-					err = errInvalidFormat
-				}
-				return nil, image.Config{}, err
-			}
-			alpha, alphaStride, err = readAlpha(chunkData, widthMinusOne, heightMinusOne, buf[0]&0x03)
-			if err != nil {
-				return nil, image.Config{}, err
-			}
-			unfilterAlpha(alpha, alphaStride, (buf[0]>>2)&0x03)
-
-		case fccVP8:
-			if wantAlpha || int32(chunkLen) < 0 {
-				return nil, image.Config{}, errInvalidFormat
-			}
-			d := vp8.NewDecoder()
-			d.Init(chunkData, int(chunkLen))
-			fh, err := d.DecodeFrameHeader()
-			if err != nil {
-				return nil, image.Config{}, err
-			}
-			if configOnly {
-				return nil, image.Config{
-					ColorModel: color.YCbCrModel,
-					Width:      fh.Width,
-					Height:     fh.Height,
-				}, nil
-			}
-			m, err := d.DecodeFrame()
-			if err != nil {
-				return nil, image.Config{}, err
-			}
-			if alpha != nil {
-				return &image.NYCbCrA{
-					YCbCr:   *m,
-					A:       alpha,
-					AStride: alphaStride,
-				}, image.Config{}, nil
-			}
-			return m, image.Config{}, nil
-
-		case fccVP8L:
-			if wantAlpha || alpha != nil {
-				return nil, image.Config{}, errInvalidFormat
-			}
-			if configOnly {
-				c, err := vp8l.DecodeConfig(chunkData)
-				return nil, c, err
-			}
-			m, err := vp8l.Decode(chunkData)
-			return m, image.Config{}, err
-
-		case fccVP8X:
-			if chunkLen != 10 {
-				return nil, image.Config{}, errInvalidFormat
-			}
-			if _, err := io.ReadFull(chunkData, buf[:10]); err != nil {
-				return nil, image.Config{}, err
-			}
-			const (
-				animationBit    = 1 << 1
-				xmpMetadataBit  = 1 << 2
-				exifMetadataBit = 1 << 3
-				alphaBit        = 1 << 4
-				iccProfileBit   = 1 << 5
-			)
-			if buf[0] != alphaBit {
-				return nil, image.Config{}, errors.New("webp: non-Alpha VP8X is not implemented")
-			}
-			widthMinusOne = uint32(buf[4]) | uint32(buf[5])<<8 | uint32(buf[6])<<16
-			heightMinusOne = uint32(buf[7]) | uint32(buf[8])<<8 | uint32(buf[9])<<16
-			if configOnly {
-				return nil, image.Config{
-					ColorModel: color.NYCbCrAModel,
-					Width:      int(widthMinusOne) + 1,
-					Height:     int(heightMinusOne) + 1,
-				}, nil
-			}
-			wantAlpha = true
-
-		default:
-			return nil, image.Config{}, errInvalidFormat
-		}
-	}
-}
-
-func readAlpha(chunkData io.Reader, widthMinusOne, heightMinusOne uint32, compression byte) (
-	alpha []byte, alphaStride int, err error) {
-
-	switch compression {
-	case 0:
-		w := int(widthMinusOne) + 1
-		h := int(heightMinusOne) + 1
-		alpha = make([]byte, w*h)
-		if _, err := io.ReadFull(chunkData, alpha); err != nil {
-			return nil, 0, err
-		}
-		return alpha, w, nil
-
-	case 1:
-		// Read the VP8L-compressed alpha values. First, synthesize a 5-byte VP8L header:
-		// a 1-byte magic number, a 14-bit widthMinusOne, a 14-bit heightMinusOne,
-		// a 1-bit (ignored, zero) alphaIsUsed and a 3-bit (zero) version.
-		// TODO(nigeltao): be more efficient than decoding an *image.NRGBA just to
-		// extract the green values to a separately allocated []byte. Fixing this
-		// will require changes to the vp8l package's API.
-		if widthMinusOne > 0x3fff || heightMinusOne > 0x3fff {
-			return nil, 0, errors.New("webp: invalid format")
-		}
-		alphaImage, err := vp8l.Decode(io.MultiReader(
-			bytes.NewReader([]byte{
-				0x2f, // VP8L magic number.
-				uint8(widthMinusOne),
-				uint8(widthMinusOne>>8) | uint8(heightMinusOne<<6),
-				uint8(heightMinusOne >> 2),
-				uint8(heightMinusOne >> 10),
-			}),
-			chunkData,
-		))
-		if err != nil {
-			return nil, 0, err
-		}
-		// The green values of the inner NRGBA image are the alpha values of the
-		// outer NYCbCrA image.
-		pix := alphaImage.(*image.NRGBA).Pix
-		alpha = make([]byte, len(pix)/4)
-		for i := range alpha {
-			alpha[i] = pix[4*i+1]
-		}
-		return alpha, int(widthMinusOne) + 1, nil
-	}
-	return nil, 0, errInvalidFormat
-}
-
-func unfilterAlpha(alpha []byte, alphaStride int, filter byte) {
-	if len(alpha) == 0 || alphaStride == 0 {
-		return
-	}
-	switch filter {
-	case 1: // Horizontal filter.
-		for i := 1; i < alphaStride; i++ {
-			alpha[i] += alpha[i-1]
-		}
-		for i := alphaStride; i < len(alpha); i += alphaStride {
-			// The first column is equivalent to the vertical filter.
-			alpha[i] += alpha[i-alphaStride]
-
-			for j := 1; j < alphaStride; j++ {
-				alpha[i+j] += alpha[i+j-1]
-			}
-		}
-
-	case 2: // Vertical filter.
-		// The first row is equivalent to the horizontal filter.
-		for i := 1; i < alphaStride; i++ {
-			alpha[i] += alpha[i-1]
-		}
-
-		for i := alphaStride; i < len(alpha); i++ {
-			alpha[i] += alpha[i-alphaStride]
-		}
-
-	case 3: // Gradient filter.
-		// The first row is equivalent to the horizontal filter.
-		for i := 1; i < alphaStride; i++ {
-			alpha[i] += alpha[i-1]
-		}
-
-		for i := alphaStride; i < len(alpha); i += alphaStride {
-			// The first column is equivalent to the vertical filter.
-			alpha[i] += alpha[i-alphaStride]
-
-			// The interior is predicted on the three top/left pixels.
-			for j := 1; j < alphaStride; j++ {
-				c := int(alpha[i+j-alphaStride-1])
-				b := int(alpha[i+j-alphaStride])
-				a := int(alpha[i+j-1])
-				x := a + b - c
-				if x < 0 {
-					x = 0
-				} else if x > 255 {
-					x = 255
-				}
-				alpha[i+j] += uint8(x)
-			}
-		}
-	}
-}
-
-// Decode reads a WEBP image from r and returns it as an image.Image.
-func Decode(r io.Reader) (image.Image, error) {
-	m, _, err := decode(r, false)
-	if err != nil {
-		return nil, err
-	}
-	return m, err
-}
-
-// DecodeConfig returns the color model and dimensions of a WEBP image without
-// decoding the entire image.
-func DecodeConfig(r io.Reader) (image.Config, error) {
-	_, c, err := decode(r, true)
-	return c, err
-}
-
-func init() {
-	image.RegisterFormat("webp", "RIFF????WEBPVP8", Decode, DecodeConfig)
-}

vendor/golang.org/x/image/webp/doc.go

@@ -1,9 +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 webp implements a decoder for WEBP images.
-//
-// WEBP is defined at:
-// https://developers.google.com/speed/webp/docs/riff_container
-package webp // import "golang.org/x/image/webp"

webp.go

@@ -0,0 +1,112 @@
+// Copyright 2011 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.
+
+// Original code was cropped and fixed by @DarthSim for imgproxy needs
+
+package main
+
+import (
+	"errors"
+	"image"
+	goColor "image/color"
+	"io"
+
+	"golang.org/x/image/riff"
+	"golang.org/x/image/vp8"
+	"golang.org/x/image/vp8l"
+)
+
+var errInvalidFormat = errors.New("webp: invalid format")
+
+var (
+	fccALPH = riff.FourCC{'A', 'L', 'P', 'H'}
+	fccVP8  = riff.FourCC{'V', 'P', '8', ' '}
+	fccVP8L = riff.FourCC{'V', 'P', '8', 'L'}
+	fccVP8X = riff.FourCC{'V', 'P', '8', 'X'}
+	fccWEBP = riff.FourCC{'W', 'E', 'B', 'P'}
+)
+
+// Since we need this only for type detecting, we can return fake image
+func decodeWebp(r io.Reader) (image.Image, error) {
+	return image.NewRGBA(image.Rect(0, 0, 1, 1)), nil
+}
+
+func decodeWebpConfig(r io.Reader) (image.Config, error) {
+	formType, riffReader, err := riff.NewReader(r)
+	if err != nil {
+		return image.Config{}, err
+	}
+	if formType != fccWEBP {
+		return image.Config{}, errInvalidFormat
+	}
+
+	var (
+		wantAlpha bool
+		buf       [10]byte
+	)
+
+	for {
+		chunkID, chunkLen, chunkData, err := riffReader.Next()
+		if err == io.EOF {
+			err = errInvalidFormat
+		}
+		if err != nil {
+			return image.Config{}, err
+		}
+
+		switch chunkID {
+		case fccALPH:
+			// Ignore
+		case fccVP8:
+			if wantAlpha || int32(chunkLen) < 0 {
+				return image.Config{}, errInvalidFormat
+			}
+
+			d := vp8.NewDecoder()
+			d.Init(chunkData, int(chunkLen))
+
+			fh, err := d.DecodeFrameHeader()
+
+			return image.Config{
+				ColorModel: goColor.YCbCrModel,
+				Width:      fh.Width,
+				Height:     fh.Height,
+			}, err
+
+		case fccVP8L:
+			if wantAlpha {
+				return image.Config{}, errInvalidFormat
+			}
+			return vp8l.DecodeConfig(chunkData)
+
+		case fccVP8X:
+			if chunkLen != 10 {
+				return image.Config{}, errInvalidFormat
+			}
+
+			if _, err := io.ReadFull(chunkData, buf[:10]); err != nil {
+				return image.Config{}, err
+			}
+
+			const alphaBit = 1 << 4
+
+			wantAlpha = buf[0] != alphaBit
+			widthMinusOne := uint32(buf[4]) | uint32(buf[5])<<8 | uint32(buf[6])<<16
+			heightMinusOne := uint32(buf[7]) | uint32(buf[8])<<8 | uint32(buf[9])<<16
+
+			return image.Config{
+				ColorModel: goColor.NYCbCrAModel,
+				Width:      int(widthMinusOne) + 1,
+				Height:     int(heightMinusOne) + 1,
+			}, nil
+
+		default:
+			return image.Config{}, errInvalidFormat
+		}
+	}
+}
+
+func init() {
+	image.RegisterFormat("webp", "RIFF????WEBPVP8", decodeWebp, decodeWebpConfig)
+}