From 9ce43ce66797c1ddfbf365dfd83e5e17a6a7717e Mon Sep 17 00:00:00 2001 From: Artyom Pervukhin Date: Wed, 11 Oct 2017 11:19:44 +0300 Subject: [PATCH] image/gif: make Decode only keep the first frame in memory Decode decodes entire GIF image and returns the first frame as an image.Image. There's no need for it to keep every decoded frame in memory except for the one it returns. Fixes #22199 Change-Id: I76b4bd31608ebc76a1a3df02e85c20eb80df7877 Reviewed-on: https://go-review.googlesource.com/69890 Reviewed-by: Nigel Tao --- src/image/gif/reader.go | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/src/image/gif/reader.go b/src/image/gif/reader.go index b1335e6125..19f3c61e5d 100644 --- a/src/image/gif/reader.go +++ b/src/image/gif/reader.go @@ -150,7 +150,7 @@ func (b *blockReader) Read(p []byte) (int, error) { } // decode reads a GIF image from r and stores the result in d. -func (d *decoder) decode(r io.Reader, configOnly bool) error { +func (d *decoder) decode(r io.Reader, configOnly, keepAllFrames bool) error { // Add buffering if r does not provide ReadByte. if rr, ok := r.(reader); ok { d.r = rr @@ -279,9 +279,11 @@ func (d *decoder) decode(r io.Reader, configOnly bool) error { uninterlace(m) } - d.image = append(d.image, m) - d.delay = append(d.delay, d.delayTime) - d.disposal = append(d.disposal, d.disposalMethod) + if keepAllFrames || len(d.image) == 0 { + d.image = append(d.image, m) + d.delay = append(d.delay, d.delayTime) + d.disposal = append(d.disposal, d.disposalMethod) + } // The GIF89a spec, Section 23 (Graphic Control Extension) says: // "The scope of this extension is the first graphic rendering block // to follow." We therefore reset the GCE fields to zero. @@ -491,7 +493,7 @@ func uninterlace(m *image.Paletted) { // image as an image.Image. func Decode(r io.Reader) (image.Image, error) { var d decoder - if err := d.decode(r, false); err != nil { + if err := d.decode(r, false, false); err != nil { return nil, err } return d.image[0], nil @@ -526,7 +528,7 @@ type GIF struct { // and timing information. func DecodeAll(r io.Reader) (*GIF, error) { var d decoder - if err := d.decode(r, false); err != nil { + if err := d.decode(r, false, true); err != nil { return nil, err } gif := &GIF{ @@ -548,7 +550,7 @@ func DecodeAll(r io.Reader) (*GIF, error) { // without decoding the entire image. func DecodeConfig(r io.Reader) (image.Config, error) { var d decoder - if err := d.decode(r, true); err != nil { + if err := d.decode(r, true, false); err != nil { return image.Config{}, err } return image.Config{ -- 2.48.1