/*

 * 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,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#include "config.h"

#if ENABLE(FILE_READER)

#include "FileReader.h"

#include "Base64.h"

#include "Blob.h"

#include "File.h"

#include "FileStreamProxy.h"

#include "Logging.h"

#include "ProgressEvent.h"

#include "ScriptExecutionContext.h"

#include "TextResourceDecoder.h"

#include <wtf/CurrentTime.h>

namespace WebCore {

const unsigned bufferSize = 1024;

const double progressNotificationIntervalMS = 50;

FileReader::FileReader(ScriptExecutionContext* context)

    : ActiveDOMObject(context, this)

    , m_state(None)

    , m_readType(ReadFileAsBinaryString)

    , m_result("")

    , m_isRawDataConverted(false)

    , m_bytesLoaded(0)

    , m_totalBytes(0)

    , m_lastProgressNotificationTimeMS(0)

{

    m_buffer.resize(bufferSize);

}

FileReader::~FileReader()

{

    terminate();

}

bool FileReader::hasPendingActivity() const

{

    return (m_state != None && m_state != Completed) || ActiveDOMObject::hasPendingActivity();

}

bool FileReader::canSuspend() const

{

    // FIXME: It is not currently possible to suspend a FileReader, so pages with FileReader can not go into page cache.

    return false;

}

void FileReader::stop()

{

    terminate();

}

void FileReader::readAsBinaryString(Blob* fileBlob)

{

    if (!fileBlob)

        return;

    // FIXME: needs to handle non-file blobs.

    LOG(FileAPI, "FileReader: reading as binary: %s\n", fileBlob->path().utf8().data());

    readInternal(fileBlob, ReadFileAsBinaryString);

}

void FileReader::readAsText(Blob* fileBlob, const String& encoding)

{

    if (!fileBlob)

        return;

    // FIXME: needs to handle non-file blobs.

    LOG(FileAPI, "FileReader: reading as text: %s\n", fileBlob->path().utf8().data());

    if (!encoding.isEmpty())

        m_encoding = TextEncoding(encoding);

    readInternal(fileBlob, ReadFileAsText);

}

void FileReader::readAsDataURL(File* file)

{

    if (!file)

        return;

    LOG(FileAPI, "FileReader: reading as data URL: %s\n", file->path().utf8().data());

    m_fileType = file->type();

    readInternal(file, ReadFileAsDataURL);

}

void FileReader::readInternal(Blob* fileBlob, ReadType type)

{

    // readAs*** methods() can be called multiple times. Only the last call before the actual reading happens is processed.

    if (m_state != None && m_state != Starting)

        return;

    m_fileBlob = fileBlob;

    m_readType = type;

    m_state = Starting;

    // When FileStreamProxy is created, FileReader::didStart() will get notified on the File thread and we will start

    // opening and reading the file since then.

    if (!m_streamProxy.get())

        m_streamProxy = FileStreamProxy::create(scriptExecutionContext(), this);

}

void FileReader::abort()

{

    LOG(FileAPI, "FileReader: aborting\n");

    terminate();

    m_result = "";

    m_error = FileError::create(ABORT_ERR);

    fireEvent(eventNames().errorEvent);

    fireEvent(eventNames().abortEvent);

    fireEvent(eventNames().loadendEvent);

}

void FileReader::terminate()

{

    if (m_streamProxy) {

        m_streamProxy->stop();

        m_streamProxy = 0;

    }

    m_state = Completed;

}

void FileReader::didStart()

{

    m_state = Opening;

    m_streamProxy->openForRead(m_fileBlob.get());

}

void FileReader::didGetSize(long long size)

{

    m_state = Reading;

    fireEvent(eventNames().loadstartEvent);

    m_totalBytes = size;

    m_streamProxy->read(&m_buffer.at(0), m_buffer.size());

}

void FileReader::didRead(const char* data, int bytesRead)

{

    ASSERT(data && bytesRead);

    // Bail out if we have aborted the reading.

    if (m_state == Completed)

      return;

    switch (m_readType) {

    case ReadFileAsBinaryString:

        m_result += String(data, static_cast<unsigned>(bytesRead));

        break;

    case ReadFileAsText:

    case ReadFileAsDataURL:

        m_rawData.append(data, static_cast<unsigned>(bytesRead));

        m_isRawDataConverted = false;

        break;

    default:

        ASSERT_NOT_REACHED();

    }

    m_bytesLoaded += bytesRead;

    // Fire the progress event at least every 50ms.

    double now = WTF::currentTimeMS();

    if (!m_lastProgressNotificationTimeMS)

        m_lastProgressNotificationTimeMS = now;

    else if (now - m_lastProgressNotificationTimeMS > progressNotificationIntervalMS) {

        fireEvent(eventNames().progressEvent);

        m_lastProgressNotificationTimeMS = now;

    }

    // Continue reading.

    m_streamProxy->read(&m_buffer.at(0), m_buffer.size());

}

void FileReader::didFinish()

{

    m_state = Completed;

    m_streamProxy->close();

    fireEvent(eventNames().loadEvent);

    fireEvent(eventNames().loadendEvent);

}

void FileReader::didFail(ExceptionCode ec)

{

    m_state = Completed;

    m_error = FileError::create(ec);

    m_streamProxy->close();

    fireEvent(eventNames().errorEvent);

    fireEvent(eventNames().loadendEvent);

}

void FileReader::fireEvent(const AtomicString& type)

{

    // FIXME: the current ProgressEvent uses "unsigned long" for total and loaded attributes. Need to talk with the spec writer to resolve the issue.

    dispatchEvent(ProgressEvent::create(type, true, static_cast<unsigned>(m_bytesLoaded), static_cast<unsigned>(m_totalBytes)));

}

FileReader::ReadyState FileReader::readyState() const

{

    switch (m_state) {

    case None:

    case Starting:

        return Empty;

    case Opening:

    case Reading:

        return Loading;

    case Completed:

        return Done;

    }

    ASSERT_NOT_REACHED();

    return Empty;

}

const ScriptString& FileReader::result()

{

    // If reading as binary string, we can return the result immediately.

    if (m_readType == ReadFileAsBinaryString)

        return m_result;

    // If we already convert the raw data received so far, we can return the result now.

    if (m_isRawDataConverted)

        return m_result;

    m_isRawDataConverted = true;

    if (m_readType == ReadFileAsText)

        convertToText();

    // For data URL, we only do the coversion until we receive all the raw data.

    else if (m_readType == ReadFileAsDataURL && m_state == Completed)

        convertToDataURL();

    return m_result;

}

void FileReader::convertToText()

{

    if (!m_rawData.size()) {

        m_result = "";

        return;

    }

    // Decode the data.

    // The File API spec says that we should use the supplied encoding if it is valid. However, we choose to ignore this

    // requirement in order to be consistent with how WebKit decodes the web content: always has the BOM override the

    // provided encoding.     

    // FIXME: consider supporting incremental decoding to improve the perf.

    if (!m_decoder)

        m_decoder = TextResourceDecoder::create("text/plain", m_encoding.isValid() ? m_encoding : UTF8Encoding());

    m_result = m_decoder->decode(&m_rawData.at(0), m_rawData.size());

    if (m_state == Completed && !m_error)

        m_result += m_decoder->flush();

}

void FileReader::convertToDataURL()

{

    m_result = "data:";

    if (!m_rawData.size())

        return;

    m_result += m_fileType;

    if (!m_fileType.isEmpty())

        m_result += ";";

    m_result += "base64,";

    Vector<char> out;

    base64Encode(m_rawData, out);

    out.append('\0');

    m_result += out.data();

}

} // namespace WebCore

#endif // ENABLE(FILE_READER)