Source/WebCore/platform/FileStream.h

/*
 * Copyright (C) 2010 Google Inc.  All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
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 *
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 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
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 * this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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#pragma once

#include <wtf/FileSystem.h>

namespace WebCore {

// All methods are synchronous.
class FileStream {
    WTF_MAKE_FAST_ALLOCATED;
public:
    FileStream();
    ~FileStream();

    // Gets the size of a file. Also validates if the file has been changed or not if the expected modification time is provided, i.e. non-zero.
    // Returns total number of bytes if successful. -1 otherwise.
    long long getSize(const String& path, Optional<WallTime> expectedModificationTime);

    // Opens a file for reading. The reading starts at the specified offset and lasts till the specified length.
    // Returns true on success. False otherwise.
    bool openForRead(const String& path, long long offset, long long length);

    // Closes the file.
    void close();

    // Reads a file into the provided data buffer.
    // Returns number of bytes being read on success. -1 otherwise.
    // If 0 is returned, it means that the reading is completed.
    int read(char* buffer, int length);

private:
    FileSystem::PlatformFileHandle m_handle;
    long long m_bytesProcessed;
    long long m_totalBytesToRead;
};

} // namespace WebCore