WebCore/html/FileReader.cpp
changeset 0 4f2f89ce4247
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebCore/html/FileReader.cpp	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,314 @@
+/*
+ * 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)