/*

 * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.

 * Copyright (C) 2008 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)

 *

 * 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 "MainResourceLoader.h"

#include "ApplicationCacheHost.h"

#include "DocumentLoader.h"

#include "FormState.h"

#include "Frame.h"

#include "FrameLoader.h"

#include "FrameLoaderClient.h"

#include "HTMLFormElement.h"

#include "Page.h"

#include "ResourceError.h"

#include "ResourceHandle.h"

#include "Settings.h"

// FIXME: More that is in common with SubresourceLoader should move up into ResourceLoader.

namespace WebCore {

MainResourceLoader::MainResourceLoader(Frame* frame)

    : ResourceLoader(frame, true, true)

    , m_dataLoadTimer(this, &MainResourceLoader::handleDataLoadNow)

    , m_loadingMultipartContent(false)

    , m_waitingForContentPolicy(false)

{

}

MainResourceLoader::~MainResourceLoader()

{

}

PassRefPtr<MainResourceLoader> MainResourceLoader::create(Frame* frame)

{

    return adoptRef(new MainResourceLoader(frame));

}

void MainResourceLoader::receivedError(const ResourceError& error)

{

    // Calling receivedMainResourceError will likely result in the last reference to this object to go away.

    RefPtr<MainResourceLoader> protect(this);

    RefPtr<Frame> protectFrame(m_frame);

    // It is important that we call FrameLoader::receivedMainResourceError before calling 

    // FrameLoader::didFailToLoad because receivedMainResourceError clears out the relevant

    // document loaders. Also, receivedMainResourceError ends up calling a FrameLoadDelegate method

    // and didFailToLoad calls a ResourceLoadDelegate method and they need to be in the correct order.

    frameLoader()->receivedMainResourceError(error, true);

    if (!cancelled()) {

        ASSERT(!reachedTerminalState());

        frameLoader()->notifier()->didFailToLoad(this, error);

        releaseResources();

    }

    ASSERT(reachedTerminalState());

}

void MainResourceLoader::didCancel(const ResourceError& error)

{

    m_dataLoadTimer.stop();

    // Calling receivedMainResourceError will likely result in the last reference to this object to go away.

    RefPtr<MainResourceLoader> protect(this);

    if (m_waitingForContentPolicy) {

        frameLoader()->policyChecker()->cancelCheck();

        ASSERT(m_waitingForContentPolicy);

        m_waitingForContentPolicy = false;

        deref(); // balances ref in didReceiveResponse

    }

    frameLoader()->receivedMainResourceError(error, true);

    ResourceLoader::didCancel(error);

}

ResourceError MainResourceLoader::interruptionForPolicyChangeError() const

{

    return frameLoader()->interruptionForPolicyChangeError(request());

}

void MainResourceLoader::stopLoadingForPolicyChange()

{

    cancel(interruptionForPolicyChangeError());

}

void MainResourceLoader::callContinueAfterNavigationPolicy(void* argument, const ResourceRequest& request, PassRefPtr<FormState>, bool shouldContinue)

{

    static_cast<MainResourceLoader*>(argument)->continueAfterNavigationPolicy(request, shouldContinue);

}

void MainResourceLoader::continueAfterNavigationPolicy(const ResourceRequest&, bool shouldContinue)

{

    if (!shouldContinue)

        stopLoadingForPolicyChange();

    deref(); // balances ref in willSendRequest

}

bool MainResourceLoader::isPostOrRedirectAfterPost(const ResourceRequest& newRequest, const ResourceResponse& redirectResponse)

{

    if (newRequest.httpMethod() == "POST")

        return true;

    int status = redirectResponse.httpStatusCode();

    if (((status >= 301 && status <= 303) || status == 307)

        && frameLoader()->initialRequest().httpMethod() == "POST")

        return true;

    return false;

}

void MainResourceLoader::addData(const char* data, int length, bool allAtOnce)

{

    ResourceLoader::addData(data, length, allAtOnce);

    frameLoader()->receivedData(data, length);

}

void MainResourceLoader::willSendRequest(ResourceRequest& newRequest, const ResourceResponse& redirectResponse)

{

    // Note that there are no asserts here as there are for the other callbacks. This is due to the

    // fact that this "callback" is sent when starting every load, and the state of callback

    // deferrals plays less of a part in this function in preventing the bad behavior deferring 

    // callbacks is meant to prevent.

    ASSERT(!newRequest.isNull());

    // The additional processing can do anything including possibly removing the last

    // reference to this object; one example of this is 3266216.

    RefPtr<MainResourceLoader> protect(this);

    // Update cookie policy base URL as URL changes, except for subframes, which use the

    // URL of the main frame which doesn't change when we redirect.

    if (frameLoader()->isLoadingMainFrame())

        newRequest.setFirstPartyForCookies(newRequest.url());

    // If we're fielding a redirect in response to a POST, force a load from origin, since

    // this is a common site technique to return to a page viewing some data that the POST

    // just modified.

    // Also, POST requests always load from origin, but this does not affect subresources.

    if (newRequest.cachePolicy() == UseProtocolCachePolicy && isPostOrRedirectAfterPost(newRequest, redirectResponse))

        newRequest.setCachePolicy(ReloadIgnoringCacheData);

    ResourceLoader::willSendRequest(newRequest, redirectResponse);

    // Don't set this on the first request. It is set when the main load was started.

    m_documentLoader->setRequest(newRequest);

    Frame* top = m_frame->tree()->top();

    if (top != m_frame)

        frameLoader()->checkIfDisplayInsecureContent(top->document()->securityOrigin(), newRequest.url());

    // FIXME: Ideally we'd stop the I/O until we hear back from the navigation policy delegate

    // listener. But there's no way to do that in practice. So instead we cancel later if the

    // listener tells us to. In practice that means the navigation policy needs to be decided

    // synchronously for these redirect cases.

    if (!redirectResponse.isNull()) {

        ref(); // balanced by deref in continueAfterNavigationPolicy

        frameLoader()->policyChecker()->checkNavigationPolicy(newRequest, callContinueAfterNavigationPolicy, this);

    }

}

static bool shouldLoadAsEmptyDocument(const KURL& url)

{

#if PLATFORM(TORCHMOBILE)

    return url.isEmpty() || (url.protocolIs("about") && equalIgnoringRef(url, blankURL()));

#else 

    return url.isEmpty() || url.protocolIs("about");

#endif

}

void MainResourceLoader::continueAfterContentPolicy(PolicyAction contentPolicy, const ResourceResponse& r)

{

    KURL url = request().url();

    const String& mimeType = r.mimeType();

    switch (contentPolicy) {

    case PolicyUse: {

        // Prevent remote web archives from loading because they can claim to be from any domain and thus avoid cross-domain security checks (4120255).

        bool isRemoteWebArchive = equalIgnoringCase("application/x-webarchive", mimeType) && !m_substituteData.isValid() && !url.isLocalFile();

        if (!frameLoader()->canShowMIMEType(mimeType) || isRemoteWebArchive) {

            frameLoader()->policyChecker()->cannotShowMIMEType(r);

            // Check reachedTerminalState since the load may have already been cancelled inside of _handleUnimplementablePolicyWithErrorCode::.

            if (!reachedTerminalState())

                stopLoadingForPolicyChange();

            return;

        }

        break;

    }

    case PolicyDownload:

        // m_handle can be null, e.g. when loading a substitute resource from application cache.

        if (!m_handle) {

            receivedError(cannotShowURLError());

            return;

        }

        frameLoader()->client()->download(m_handle.get(), request(), m_handle.get()->request(), r);

        // It might have gone missing

        if (frameLoader())

            receivedError(interruptionForPolicyChangeError());

        return;

    case PolicyIgnore:

        stopLoadingForPolicyChange();

        return;

    default:

        ASSERT_NOT_REACHED();

    }

    RefPtr<MainResourceLoader> protect(this);

    if (r.isHTTP()) {

        int status = r.httpStatusCode();

        if (status < 200 || status >= 300) {

            bool hostedByObject = frameLoader()->isHostedByObjectElement();

            frameLoader()->handleFallbackContent();

            // object elements are no longer rendered after we fallback, so don't

            // keep trying to process data from their load

            if (hostedByObject)

                cancel();

        }

    }

    // we may have cancelled this load as part of switching to fallback content

    if (!reachedTerminalState())

        ResourceLoader::didReceiveResponse(r);

    if (frameLoader() && !frameLoader()->isStopping()) {

        if (m_substituteData.isValid()) {

            if (m_substituteData.content()->size())

                didReceiveData(m_substituteData.content()->data(), m_substituteData.content()->size(), m_substituteData.content()->size(), true);

            if (frameLoader() && !frameLoader()->isStopping()) 

                didFinishLoading();

        } else if (shouldLoadAsEmptyDocument(url) || frameLoader()->representationExistsForURLScheme(url.protocol()))

            didFinishLoading();

    }

}

void MainResourceLoader::callContinueAfterContentPolicy(void* argument, PolicyAction policy)

{

    static_cast<MainResourceLoader*>(argument)->continueAfterContentPolicy(policy);

}

void MainResourceLoader::continueAfterContentPolicy(PolicyAction policy)

{

    ASSERT(m_waitingForContentPolicy);

    m_waitingForContentPolicy = false;

    if (frameLoader() && !frameLoader()->isStopping())

        continueAfterContentPolicy(policy, m_response);

    deref(); // balances ref in didReceiveResponse

}

void MainResourceLoader::didReceiveResponse(const ResourceResponse& r)

{

#if ENABLE(OFFLINE_WEB_APPLICATIONS)

    if (documentLoader()->applicationCacheHost()->maybeLoadFallbackForMainResponse(request(), r))

        return;

#endif

    HTTPHeaderMap::const_iterator it = r.httpHeaderFields().find(AtomicString("x-frame-options"));

    if (it != r.httpHeaderFields().end()) {

        String content = it->second;

        if (m_frame->loader()->shouldInterruptLoadForXFrameOptions(content, r.url())) {

            cancel();

            return;

        }

    }

    // There is a bug in CFNetwork where callbacks can be dispatched even when loads are deferred.

    // See <rdar://problem/6304600> for more details.

#if !PLATFORM(CF)

    ASSERT(shouldLoadAsEmptyDocument(r.url()) || !defersLoading());

#endif

    if (m_loadingMultipartContent) {

        frameLoader()->setupForReplaceByMIMEType(r.mimeType());

        clearResourceData();

    }

    if (r.isMultipart())

        m_loadingMultipartContent = true;

    // The additional processing can do anything including possibly removing the last

    // reference to this object; one example of this is 3266216.

    RefPtr<MainResourceLoader> protect(this);

    m_documentLoader->setResponse(r);

    m_response = r;

    ASSERT(!m_waitingForContentPolicy);

    m_waitingForContentPolicy = true;

    ref(); // balanced by deref in continueAfterContentPolicy and didCancel

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

    // Always show content with valid substitute data.

    if (frameLoader()->activeDocumentLoader()->substituteData().isValid()) {

        callContinueAfterContentPolicy(this, PolicyUse);

        return;

    }

#if ENABLE(FTPDIR)

    // Respect the hidden FTP Directory Listing pref so it can be tested even if the policy delegate might otherwise disallow it

    Settings* settings = m_frame->settings();

    if (settings && settings->forceFTPDirectoryListings() && m_response.mimeType() == "application/x-ftp-directory") {

        callContinueAfterContentPolicy(this, PolicyUse);

        return;

    }

#endif

    frameLoader()->policyChecker()->checkContentPolicy(m_response.mimeType(), callContinueAfterContentPolicy, this);

}

void MainResourceLoader::didReceiveData(const char* data, int length, long long lengthReceived, bool allAtOnce)

{

    ASSERT(data);

    ASSERT(length != 0);

    ASSERT(!m_response.isNull());

#if USE(CFNETWORK) || (PLATFORM(MAC) && !defined(BUILDING_ON_TIGER))

    // Workaround for <rdar://problem/6060782>

    if (m_response.isNull()) {

        m_response = ResourceResponse(KURL(), "text/html", 0, String(), String());

        if (DocumentLoader* documentLoader = frameLoader()->activeDocumentLoader())

            documentLoader->setResponse(m_response);

    }

#endif

    // There is a bug in CFNetwork where callbacks can be dispatched even when loads are deferred.

    // See <rdar://problem/6304600> for more details.

#if !PLATFORM(CF)

    ASSERT(!defersLoading());

#endif

 #if ENABLE(OFFLINE_WEB_APPLICATIONS)

    documentLoader()->applicationCacheHost()->mainResourceDataReceived(data, length, lengthReceived, allAtOnce);

#endif

    // The additional processing can do anything including possibly removing the last

    // reference to this object; one example of this is 3266216.

    RefPtr<MainResourceLoader> protect(this);

    ResourceLoader::didReceiveData(data, length, lengthReceived, allAtOnce);

}

void MainResourceLoader::didFinishLoading()

{

    // There is a bug in CFNetwork where callbacks can be dispatched even when loads are deferred.

    // See <rdar://problem/6304600> for more details.

#if !PLATFORM(CF)

    ASSERT(shouldLoadAsEmptyDocument(frameLoader()->activeDocumentLoader()->url()) || !defersLoading());

#endif

    // The additional processing can do anything including possibly removing the last

    // reference to this object.

    RefPtr<MainResourceLoader> protect(this);

#if ENABLE(OFFLINE_WEB_APPLICATIONS)

    RefPtr<DocumentLoader> dl = documentLoader();

#endif

    frameLoader()->finishedLoading();

    ResourceLoader::didFinishLoading();

#if ENABLE(OFFLINE_WEB_APPLICATIONS)

    dl->applicationCacheHost()->finishedLoadingMainResource();

#endif

}

void MainResourceLoader::didFail(const ResourceError& error)

{

#if ENABLE(OFFLINE_WEB_APPLICATIONS)

    if (documentLoader()->applicationCacheHost()->maybeLoadFallbackForMainError(request(), error))

        return;

#endif

    // There is a bug in CFNetwork where callbacks can be dispatched even when loads are deferred.

    // See <rdar://problem/6304600> for more details.

#if !PLATFORM(CF)

    ASSERT(!defersLoading());

#endif

    receivedError(error);

}

void MainResourceLoader::handleEmptyLoad(const KURL& url, bool forURLScheme)

{

    String mimeType;

    if (forURLScheme)

        mimeType = frameLoader()->generatedMIMETypeForURLScheme(url.protocol());

    else

        mimeType = "text/html";

    ResourceResponse response(url, mimeType, 0, String(), String());

    didReceiveResponse(response);

}

void MainResourceLoader::handleDataLoadNow(MainResourceLoaderTimer*)

{

    RefPtr<MainResourceLoader> protect(this);

    KURL url = m_substituteData.responseURL();

    if (url.isEmpty())

        url = m_initialRequest.url();

    // Clear the initial request here so that subsequent entries into the

    // loader will not think there's still a deferred load left to do.

    m_initialRequest = ResourceRequest();

    ResourceResponse response(url, m_substituteData.mimeType(), m_substituteData.content()->size(), m_substituteData.textEncoding(), "");

    didReceiveResponse(response);

}

void MainResourceLoader::startDataLoadTimer()

{

    m_dataLoadTimer.startOneShot(0);

#if HAVE(RUNLOOP_TIMER)

    if (SchedulePairHashSet* scheduledPairs = m_frame->page()->scheduledRunLoopPairs())

        m_dataLoadTimer.schedule(*scheduledPairs);

#endif

}

void MainResourceLoader::handleDataLoadSoon(ResourceRequest& r)

{

    m_initialRequest = r;

    if (m_documentLoader->deferMainResourceDataLoad())

        startDataLoadTimer();

    else

        handleDataLoadNow(0);

}

bool MainResourceLoader::loadNow(ResourceRequest& r)

{

    bool shouldLoadEmptyBeforeRedirect = shouldLoadAsEmptyDocument(r.url());

    ASSERT(!m_handle);

    ASSERT(shouldLoadEmptyBeforeRedirect || !defersLoading());

    // Send this synthetic delegate callback since clients expect it, and

    // we no longer send the callback from within NSURLConnection for

    // initial requests.

    willSendRequest(r, ResourceResponse());

    // <rdar://problem/4801066>

    // willSendRequest() is liable to make the call to frameLoader() return NULL, so we need to check that here

    if (!frameLoader())

        return false;

    const KURL& url = r.url();

    bool shouldLoadEmpty = shouldLoadAsEmptyDocument(url) && !m_substituteData.isValid();

    if (shouldLoadEmptyBeforeRedirect && !shouldLoadEmpty && defersLoading())

        return true;

    if (m_substituteData.isValid()) 

        handleDataLoadSoon(r);

    else if (shouldLoadEmpty || frameLoader()->representationExistsForURLScheme(url.protocol()))

        handleEmptyLoad(url, !shouldLoadEmpty);

    else

        m_handle = ResourceHandle::create(r, this, m_frame.get(), false, true, true);

    return false;

}

bool MainResourceLoader::load(const ResourceRequest& r, const SubstituteData& substituteData)

{

    ASSERT(!m_handle);

    m_substituteData = substituteData;

    ResourceRequest request(r);

#if ENABLE(OFFLINE_WEB_APPLICATIONS)

    documentLoader()->applicationCacheHost()->maybeLoadMainResource(request, m_substituteData);

#endif

    bool defer = defersLoading();

    if (defer) {

        bool shouldLoadEmpty = shouldLoadAsEmptyDocument(request.url());

        if (shouldLoadEmpty)

            defer = false;

    }

    if (!defer) {

        if (loadNow(request)) {

            // Started as an empty document, but was redirected to something non-empty.

            ASSERT(defersLoading());

            defer = true;

        }

    }

    if (defer)

        m_initialRequest = request;

    return true;

}