/*

 * Copyright (C) 2006, 2007, 2008 Apple 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:

 *

 * 1.  Redistributions of source code must retain the above copyright

 *     notice, this list of conditions and the following disclaimer. 

 * 2.  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. 

 * 3.  Neither the name of Apple Computer, Inc. ("Apple") 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 APPLE AND ITS 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 APPLE OR ITS 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"

#include "DocumentLoader.h"

#include "ApplicationCacheHost.h"

#include "ArchiveFactory.h"

#include "ArchiveResourceCollection.h"

#include "CachedPage.h"

#include "DocLoader.h"

#include "Document.h"

#include "Event.h"

#include "Frame.h"

#include "FrameLoader.h"

#include "FrameTree.h"

#include "HistoryItem.h"

#include "Logging.h"

#include "MainResourceLoader.h"

#include "Page.h"

#include "PlatformString.h"

#include "Settings.h"

#include "SharedBuffer.h"

#include "StringBuffer.h"

#include "XMLTokenizer.h"

#include <wtf/Assertions.h>

#include <wtf/unicode/Unicode.h>

namespace WebCore {

/*

 * Performs four operations:

 *  1. Convert backslashes to currency symbols

 *  2. Convert control characters to spaces

 *  3. Trim leading and trailing spaces

 *  4. Collapse internal whitespace.

 */

static inline String canonicalizedTitle(const String& title, Frame* frame)

{

    ASSERT(!title.isEmpty());

    const UChar* characters = title.characters();

    unsigned length = title.length();

    unsigned i;

    StringBuffer buffer(length);

    unsigned builderIndex = 0;

    // Skip leading spaces and leading characters that would convert to spaces

    for (i = 0; i < length; ++i) {

        UChar c = characters[i];

        if (!(c <= 0x20 || c == 0x7F))

            break;

    }

    if (i == length)

        return "";

    // Replace control characters with spaces, and backslashes with currency symbols, and collapse whitespace.

    bool previousCharWasWS = false;

    for (; i < length; ++i) {

        UChar c = characters[i];

        if (c <= 0x20 || c == 0x7F || (WTF::Unicode::category(c) & (WTF::Unicode::Separator_Line | WTF::Unicode::Separator_Paragraph))) {

            if (previousCharWasWS)

                continue;

            buffer[builderIndex++] = ' ';

            previousCharWasWS = true;

        } else {

            buffer[builderIndex++] = c;

            previousCharWasWS = false;

        }

    }

    // Strip trailing spaces

    while (builderIndex > 0) {

        --builderIndex;

        if (buffer[builderIndex] != ' ')

            break;

    }

    if (!builderIndex && buffer[builderIndex] == ' ')

        return "";

    buffer.shrink(builderIndex + 1);

    // Replace the backslashes with currency symbols if the encoding requires it.

    frame->document()->displayBufferModifiedByEncoding(buffer.characters(), buffer.length());

    return String::adopt(buffer);

}

static void cancelAll(const ResourceLoaderSet& loaders)

{

    const ResourceLoaderSet copy = loaders;

    ResourceLoaderSet::const_iterator end = copy.end();

    for (ResourceLoaderSet::const_iterator it = copy.begin(); it != end; ++it)

        (*it)->cancel();

}

static void setAllDefersLoading(const ResourceLoaderSet& loaders, bool defers)

{

    const ResourceLoaderSet copy = loaders;

    ResourceLoaderSet::const_iterator end = copy.end();

    for (ResourceLoaderSet::const_iterator it = copy.begin(); it != end; ++it)

        (*it)->setDefersLoading(defers);

}

DocumentLoader::DocumentLoader(const ResourceRequest& req, const SubstituteData& substituteData)

    : m_deferMainResourceDataLoad(true)

    , m_frame(0)

    , m_originalRequest(req)

    , m_substituteData(substituteData)

    , m_originalRequestCopy(req)

    , m_request(req)

    , m_committed(false)

    , m_isStopping(false)

    , m_loading(false)

    , m_gotFirstByte(false)

    , m_primaryLoadComplete(false)

    , m_isClientRedirect(false)

    , m_stopRecordingResponses(false)

    , m_substituteResourceDeliveryTimer(this, &DocumentLoader::substituteResourceDeliveryTimerFired)

    , m_didCreateGlobalHistoryEntry(false)

#if ENABLE(OFFLINE_WEB_APPLICATIONS)

    , m_applicationCacheHost(new ApplicationCacheHost(this))

#endif

{

}

FrameLoader* DocumentLoader::frameLoader() const

{

    if (!m_frame)

        return 0;

    return m_frame->loader();

}

DocumentLoader::~DocumentLoader()

{

    ASSERT(!m_frame || frameLoader()->activeDocumentLoader() != this || !frameLoader()->isLoading());

}

PassRefPtr<SharedBuffer> DocumentLoader::mainResourceData() const

{

    if (m_mainResourceData)

        return m_mainResourceData;

    if (m_mainResourceLoader)

        return m_mainResourceLoader->resourceData();

    return 0;

}

const ResourceRequest& DocumentLoader::originalRequest() const

{

    return m_originalRequest;

}

const ResourceRequest& DocumentLoader::originalRequestCopy() const

{

    return m_originalRequestCopy;

}

const ResourceRequest& DocumentLoader::request() const

{

    return m_request;

}

ResourceRequest& DocumentLoader::request()

{

    return m_request;

}

const KURL& DocumentLoader::url() const

{

    return request().url();

}

void DocumentLoader::replaceRequestURLForAnchorScroll(const KURL& url)

{

    m_originalRequestCopy.setURL(url);

    m_request.setURL(url);

}

void DocumentLoader::setRequest(const ResourceRequest& req)

{

    // Replacing an unreachable URL with alternate content looks like a server-side

    // redirect at this point, but we can replace a committed dataSource.

    bool handlingUnreachableURL = false;

    handlingUnreachableURL = m_substituteData.isValid() && !m_substituteData.failingURL().isEmpty();

    if (handlingUnreachableURL)

        m_committed = false;

    // We should never be getting a redirect callback after the data

    // source is committed, except in the unreachable URL case. It 

    // would be a WebFoundation bug if it sent a redirect callback after commit.

    ASSERT(!m_committed);

    KURL oldURL = m_request.url();

    m_request = req;

    // Only send webView:didReceiveServerRedirectForProvisionalLoadForFrame: if URL changed.

    // Also, don't send it when replacing unreachable URLs with alternate content.

    if (!handlingUnreachableURL && oldURL != req.url())

        frameLoader()->didReceiveServerRedirectForProvisionalLoadForFrame();

}

void DocumentLoader::setMainDocumentError(const ResourceError& error)

{

    m_mainDocumentError = error;    

    frameLoader()->setMainDocumentError(this, error);

 }

void DocumentLoader::clearErrors()

{

    m_mainDocumentError = ResourceError();

}

void DocumentLoader::mainReceivedError(const ResourceError& error, bool isComplete)

{

    ASSERT(!error.isNull());

#if ENABLE(OFFLINE_WEB_APPLICATIONS)

    m_applicationCacheHost->failedLoadingMainResource();

#endif

    if (!frameLoader())

        return;

    setMainDocumentError(error);

    if (isComplete)

        frameLoader()->mainReceivedCompleteError(this, error);

}

// Cancels the data source's pending loads.  Conceptually, a data source only loads

// one document at a time, but one document may have many related resources. 

// stopLoading will stop all loads initiated by the data source, 

// but not loads initiated by child frames' data sources -- that's the WebFrame's job.

void DocumentLoader::stopLoading(DatabasePolicy databasePolicy)

{

    // In some rare cases, calling FrameLoader::stopLoading could set m_loading to false.

    // (This can happen when there's a single XMLHttpRequest currently loading and stopLoading causes it

    // to stop loading. Because of this, we need to save it so we don't return early.

    bool loading = m_loading;

    if (m_committed) {

        // Attempt to stop the frame if the document loader is loading, or if it is done loading but

        // still  parsing. Failure to do so can cause a world leak.

        Document* doc = m_frame->document();

        if (loading || doc->parsing())

            m_frame->loader()->stopLoading(UnloadEventPolicyNone, databasePolicy);

    }

    // Always cancel multipart loaders

    cancelAll(m_multipartSubresourceLoaders);

    if (!loading)

        return;

    RefPtr<Frame> protectFrame(m_frame);

    RefPtr<DocumentLoader> protectLoader(this);

    m_isStopping = true;

    FrameLoader* frameLoader = DocumentLoader::frameLoader();

    if (m_mainResourceLoader)

        // Stop the main resource loader and let it send the cancelled message.

        m_mainResourceLoader->cancel();

    else if (!m_subresourceLoaders.isEmpty())

        // The main resource loader already finished loading. Set the cancelled error on the 

        // document and let the subresourceLoaders send individual cancelled messages below.

        setMainDocumentError(frameLoader->cancelledError(m_request));

    else

        // If there are no resource loaders, we need to manufacture a cancelled message.

        // (A back/forward navigation has no resource loaders because its resources are cached.)

        mainReceivedError(frameLoader->cancelledError(m_request), true);

    stopLoadingSubresources();

    stopLoadingPlugIns();

    m_isStopping = false;

}

void DocumentLoader::setupForReplace()

{

    frameLoader()->setupForReplace();

    m_committed = false;

}

void DocumentLoader::commitIfReady()

{

    if (m_gotFirstByte && !m_committed) {

        m_committed = true;

        frameLoader()->commitProvisionalLoad(0);

    }

}

void DocumentLoader::finishedLoading()

{

    m_gotFirstByte = true;   

    commitIfReady();

    if (FrameLoader* loader = frameLoader()) {

        loader->finishedLoadingDocument(this);

        loader->end();

    }

}

void DocumentLoader::commitLoad(const char* data, int length)

{

    // Both unloading the old page and parsing the new page may execute JavaScript which destroys the datasource

    // by starting a new load, so retain temporarily.

    RefPtr<DocumentLoader> protect(this);

    commitIfReady();

    if (FrameLoader* frameLoader = DocumentLoader::frameLoader())

        frameLoader->committedLoad(this, data, length);

}

bool DocumentLoader::doesProgressiveLoad(const String& MIMEType) const

{

    return !frameLoader()->isReplacing() || MIMEType == "text/html";

}

void DocumentLoader::receivedData(const char* data, int length)

{    

    m_gotFirstByte = true;

    if (doesProgressiveLoad(m_response.mimeType()))

        commitLoad(data, length);

}

void DocumentLoader::setupForReplaceByMIMEType(const String& newMIMEType)

{

    if (!m_gotFirstByte)

        return;

    String oldMIMEType = m_response.mimeType();

    if (!doesProgressiveLoad(oldMIMEType)) {

        frameLoader()->revertToProvisional(this);

        setupForReplace();

        RefPtr<SharedBuffer> resourceData = mainResourceData();

        commitLoad(resourceData->data(), resourceData->size());

    }

    frameLoader()->finishedLoadingDocument(this);

    m_frame->loader()->end();

    frameLoader()->setReplacing();

    m_gotFirstByte = false;

    if (doesProgressiveLoad(newMIMEType)) {

        frameLoader()->revertToProvisional(this);

        setupForReplace();

    }

    stopLoadingSubresources();

    stopLoadingPlugIns();

    clearArchiveResources();

}

void DocumentLoader::updateLoading()

{

    if (!m_frame) {

        setLoading(false);

        return;

    }

    ASSERT(this == frameLoader()->activeDocumentLoader());

    setLoading(frameLoader()->isLoading());

}

void DocumentLoader::setFrame(Frame* frame)

{

    if (m_frame == frame)

        return;

    ASSERT(frame && !m_frame);

    m_frame = frame;

    attachToFrame();

}

void DocumentLoader::attachToFrame()

{

    ASSERT(m_frame);

}

void DocumentLoader::detachFromFrame()

{

    ASSERT(m_frame);

#if ENABLE(OFFLINE_WEB_APPLICATIONS)

    m_applicationCacheHost->setDOMApplicationCache(0);

#endif

    m_frame = 0;

}

void DocumentLoader::prepareForLoadStart()

{

    ASSERT(!m_isStopping);

    setPrimaryLoadComplete(false);

    ASSERT(frameLoader());

    clearErrors();

    setLoading(true);

    frameLoader()->prepareForLoadStart();

}

void DocumentLoader::setPrimaryLoadComplete(bool flag)

{

    m_primaryLoadComplete = flag;

    if (flag) {

        if (m_mainResourceLoader) {

            m_mainResourceData = m_mainResourceLoader->resourceData();

            m_mainResourceLoader = 0;

        }

        if (this == frameLoader()->activeDocumentLoader())

            updateLoading();

    }

}

bool DocumentLoader::isLoadingInAPISense() const

{

    // Once a frame has loaded, we no longer need to consider subresources,

    // but we still need to consider subframes.

    if (frameLoader()->state() != FrameStateComplete) {

        if (!m_primaryLoadComplete && isLoading())

            return true;

        if (!m_subresourceLoaders.isEmpty())

            return true;

        Document* doc = m_frame->document();

        if (doc->docLoader()->requestCount())

            return true;

        if (Tokenizer* tok = doc->tokenizer())

            if (tok->processingData())

                return true;

    }

    return frameLoader()->subframeIsLoading();

}

void DocumentLoader::addAllArchiveResources(Archive* archive)

{

    if (!m_archiveResourceCollection)

        m_archiveResourceCollection.set(new ArchiveResourceCollection);

    ASSERT(archive);

    if (!archive)

        return;

    m_archiveResourceCollection->addAllResources(archive);

}

// FIXME: Adding a resource directly to a DocumentLoader/ArchiveResourceCollection seems like bad design, but is API some apps rely on.

// Can we change the design in a manner that will let us deprecate that API without reducing functionality of those apps?

void DocumentLoader::addArchiveResource(PassRefPtr<ArchiveResource> resource)

{

    if (!m_archiveResourceCollection)

        m_archiveResourceCollection.set(new ArchiveResourceCollection);

    ASSERT(resource);

    if (!resource)

        return;

    m_archiveResourceCollection->addResource(resource);

}

ArchiveResource* DocumentLoader::archiveResourceForURL(const KURL& url) const

{

    if (!m_archiveResourceCollection)

        return 0;

    ArchiveResource* resource = m_archiveResourceCollection->archiveResourceForURL(url);

    return resource && !resource->shouldIgnoreWhenUnarchiving() ? resource : 0;

}

PassRefPtr<Archive> DocumentLoader::popArchiveForSubframe(const String& frameName)

{

    return m_archiveResourceCollection ? m_archiveResourceCollection->popSubframeArchive(frameName) : 0;

}

void DocumentLoader::clearArchiveResources()

{

    m_archiveResourceCollection.clear();

    m_substituteResourceDeliveryTimer.stop();

}

void DocumentLoader::setParsedArchiveData(PassRefPtr<SharedBuffer> data)

{

    m_parsedArchiveData = data;

}

SharedBuffer* DocumentLoader::parsedArchiveData() const

{

    return m_parsedArchiveData.get();

}

PassRefPtr<ArchiveResource> DocumentLoader::mainResource() const

{

    const ResourceResponse& r = response();

    RefPtr<SharedBuffer> mainResourceBuffer = mainResourceData();

    if (!mainResourceBuffer)

        mainResourceBuffer = SharedBuffer::create();