/*
 * Copyright (C) 2010 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * 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
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#pragma once

#include <wtf/FileHandle.h>
#include <wtf/FileSystem.h>
#include <wtf/TZoneMalloc.h>

namespace WebCore {

// All methods are synchronous.
class FileStream {
    WTF_MAKE_TZONE_ALLOCATED(FileStream);
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, std::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(std::span<uint8_t> buffer);

private:
    FileSystem::FileHandle m_handle;
    long long m_bytesProcessed { 0 };
    long long m_totalBytesToRead { 0 };
};

} // namespace WebCore
