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// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_PAINT_PREVIEW_COMMON_FILE_STREAM_H_
#define COMPONENTS_PAINT_PREVIEW_COMMON_FILE_STREAM_H_
#include "base/files/file.h"
#include "third_party/skia/include/core/SkStream.h"
namespace paint_preview {
// An implementation of the SkWStream interface backed by base::File.
class FileWStream : public SkWStream {
public:
// Note: |file| must support writing. |max_size| of 0 means unlimited size.
explicit FileWStream(base::File file);
FileWStream(base::File file, size_t max_size);
~FileWStream() override;
// SkWStream impl.
bool write(const void* buffer, size_t size) override;
void flush() override;
// NOTE: this returns |fake_bytes_written_| rather than |bytes_written_| in
// order to hack around the fact that Skia requires serialization to succeed.
// This hack is necessary to:
// 1. Prevents crashes when a file cannot be enlarged due to running out of
// device disk space.
// 2. Allows us to artificially cap the size of a SkPicture when writing it to
// avoid using consuming an unreasonable amount of disk space.
size_t bytesWritten() const override;
// Closes the file (occurs automatically on destruction).
void Close();
bool DidWriteFail() const { return has_write_failed_; }
size_t ActualBytesWritten() const { return bytes_written_; }
private:
base::File file_;
size_t max_size_;
size_t bytes_written_;
size_t fake_bytes_written_;
bool has_write_failed_;
FileWStream(const FileWStream&) = delete;
FileWStream& operator=(const FileWStream&) = delete;
};
// An implementation of the SkWStream interface backed by base::File. Only
// implements the minimal interface and not the Seekable/Rewindable variants.
class FileRStream : public SkStream {
public:
// Note: |file| must support reading. It *cannot* be modified while streaming.
explicit FileRStream(base::File file);
~FileRStream() override;
size_t length() const { return length_; }
// SkStream impl.
size_t read(void* buffer, size_t size) override;
bool isAtEnd() const override;
bool hasLength() const override;
size_t getLength() const override;
private:
base::File file_;
// Length is fixed at the start of streaming as the file should not be
// modified. This value must be cached as base::File::GetLength() is not a
// const operation.
const size_t length_;
size_t bytes_read_;
FileRStream(const FileRStream&) = delete;
FileRStream& operator=(const FileRStream&) = delete;
};
} // namespace paint_preview
#endif // COMPONENTS_PAINT_PREVIEW_COMMON_FILE_STREAM_H_
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