Move gif image decoder to SkCodec

third_party/WebKit/Source/platform/image-decoders/SegmentStream.h

+// Copyright (c) 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SegmentStream_h
+#define SegmentStream_h
+
+#include <algorithm>
+#include "platform/PlatformExport.h"
+#include "platform/wtf/RefPtr.h"
+#include "third_party/skia/include/core/SkStream.h"
+
+namespace blink {
+
+class SegmentReader;
+
+class PLATFORM_EXPORT SegmentStream : public SkStream {
+ public:
+  SegmentStream();
+  SegmentStream(const SegmentStream&) = delete;
+  SegmentStream& operator=(const SegmentStream&) = delete;
+  SegmentStream(SegmentStream&&);
+  SegmentStream& operator=(SegmentStream&&);
+
+  ~SegmentStream() override;
+
+  void SetReader(WTF::RefPtr<SegmentReader>);
+  // If a buffer has shrunk beyond the point we have read, it has been cleared.
+  // This allows clients to be aware of when data suddenly disappears.
+  bool IsCleared() const;
+
+  // From SkStream:
+  size_t read(void* buffer, size_t) override;
+  size_t peek(void* buffer, size_t) const override;
+  bool isAtEnd() const override;
+  bool rewind() override;
+  bool hasPosition() const override { return true; }
+  size_t getPosition() const override { return position_; }
+  bool seek(size_t position) override;
+  bool move(long offset) override;
+  bool hasLength() const override { return true; }
+  size_t getLength() const override;
+
+ private:
+  WTF::RefPtr<SegmentReader> reader_;
+  size_t position_ = 0;
+};
+
+}  // namespace blink
+
+#endif