/*

 * Copyright (C) 2009 Google Inc. All rights reserved.

 *

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 * 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

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

 */

#include "config.h"

#include "DocumentThreadableLoader.h"

#include "AuthenticationChallenge.h"

#include "CrossOriginAccessControl.h"

#include "CrossOriginPreflightResultCache.h"

#include "Document.h"

#include "Frame.h"

#include "FrameLoader.h"

#include "ResourceHandle.h"

#include "ResourceRequest.h"

#include "SecurityOrigin.h"

#include "SubresourceLoader.h"

#include "ThreadableLoaderClient.h"

#include <wtf/UnusedParam.h>

namespace WebCore {

void DocumentThreadableLoader::loadResourceSynchronously(Document* document, const ResourceRequest& request, ThreadableLoaderClient& client, const ThreadableLoaderOptions& options)

{

    // The loader will be deleted as soon as this function exits.

    RefPtr<DocumentThreadableLoader> loader = adoptRef(new DocumentThreadableLoader(document, &client, LoadSynchronously, request, options));

    ASSERT(loader->hasOneRef());

}

PassRefPtr<DocumentThreadableLoader> DocumentThreadableLoader::create(Document* document, ThreadableLoaderClient* client, const ResourceRequest& request, const ThreadableLoaderOptions& options)

{

    RefPtr<DocumentThreadableLoader> loader = adoptRef(new DocumentThreadableLoader(document, client, LoadAsynchronously, request, options));

    if (!loader->m_loader)

        loader = 0;

    return loader.release();

}

DocumentThreadableLoader::DocumentThreadableLoader(Document* document, ThreadableLoaderClient* client, BlockingBehavior blockingBehavior, const ResourceRequest& request, const ThreadableLoaderOptions& options)

    : m_client(client)

    , m_document(document)

    , m_options(options)

    , m_sameOriginRequest(document->securityOrigin()->canRequest(request.url()))

    , m_async(blockingBehavior == LoadAsynchronously)

{

    ASSERT(document);

    ASSERT(client);

    if (m_sameOriginRequest || m_options.crossOriginRequestPolicy == AllowCrossOriginRequests) {

        loadRequest(request, DoSecurityCheck);

        return;

    }

    if (m_options.crossOriginRequestPolicy == DenyCrossOriginRequests) {

        m_client->didFail(ResourceError(errorDomainWebKitInternal, 0, request.url().string(), "Cross origin requests are not supported."));

        return;

    }

    ASSERT(m_options.crossOriginRequestPolicy == UseAccessControl);

    OwnPtr<ResourceRequest> crossOriginRequest(new ResourceRequest(request));

    crossOriginRequest->removeCredentials();

    crossOriginRequest->setAllowCookies(m_options.allowCredentials);

    if (!m_options.forcePreflight && isSimpleCrossOriginAccessRequest(crossOriginRequest->httpMethod(), crossOriginRequest->httpHeaderFields()))

        makeSimpleCrossOriginAccessRequest(*crossOriginRequest);

    else {

        m_actualRequest = crossOriginRequest.release();

        if (CrossOriginPreflightResultCache::shared().canSkipPreflight(document->securityOrigin()->toString(), m_actualRequest->url(), m_options.allowCredentials, m_actualRequest->httpMethod(), m_actualRequest->httpHeaderFields()))

            preflightSuccess();

        else

            makeCrossOriginAccessRequestWithPreflight(*m_actualRequest);

    }

}

void DocumentThreadableLoader::makeSimpleCrossOriginAccessRequest(const ResourceRequest& request)

{

    ASSERT(isSimpleCrossOriginAccessRequest(request.httpMethod(), request.httpHeaderFields()));

    // Cross-origin requests are only defined for HTTP. We would catch this when checking response headers later, but there is no reason to send a request that's guaranteed to be denied.

    if (!request.url().protocolInHTTPFamily()) {

        m_client->didFail(ResourceError(errorDomainWebKitInternal, 0, request.url().string(), "Cross origin requests are only supported for HTTP."));

        return;

    }

    // Make a copy of the passed request so that we can modify some details.

    ResourceRequest crossOriginRequest(request);

    crossOriginRequest.setHTTPOrigin(m_document->securityOrigin()->toString());

    loadRequest(crossOriginRequest, DoSecurityCheck);

}

void DocumentThreadableLoader::makeCrossOriginAccessRequestWithPreflight(const ResourceRequest& request)

{

    ResourceRequest preflightRequest(request.url());

    preflightRequest.removeCredentials();

    preflightRequest.setHTTPOrigin(m_document->securityOrigin()->toString());

    preflightRequest.setAllowCookies(m_options.allowCredentials);

    preflightRequest.setHTTPMethod("OPTIONS");

    preflightRequest.setHTTPHeaderField("Access-Control-Request-Method", request.httpMethod());

    const HTTPHeaderMap& requestHeaderFields = request.httpHeaderFields();

    if (requestHeaderFields.size() > 0) {

        Vector<UChar> headerBuffer;

        HTTPHeaderMap::const_iterator it = requestHeaderFields.begin();

        append(headerBuffer, it->first);

        ++it;

        HTTPHeaderMap::const_iterator end = requestHeaderFields.end();

        for (; it != end; ++it) {

            headerBuffer.append(',');

            headerBuffer.append(' ');

            append(headerBuffer, it->first);

        }

        preflightRequest.setHTTPHeaderField("Access-Control-Request-Headers", String::adopt(headerBuffer));

    }

    loadRequest(preflightRequest, DoSecurityCheck);

}

DocumentThreadableLoader::~DocumentThreadableLoader()

{

    if (m_loader)

        m_loader->clearClient();

}

void DocumentThreadableLoader::cancel()

{

    if (!m_loader)

        return;

    m_loader->cancel();

    m_loader->clearClient();

    m_loader = 0;

    m_client = 0;

}

void DocumentThreadableLoader::willSendRequest(SubresourceLoader* loader, ResourceRequest& request, const ResourceResponse&)

{

    ASSERT(m_client);

    ASSERT_UNUSED(loader, loader == m_loader);

    if (!isAllowedRedirect(request.url())) {

        RefPtr<DocumentThreadableLoader> protect(this);

        m_client->didFailRedirectCheck();

        request = ResourceRequest();

    }

}

void DocumentThreadableLoader::didSendData(SubresourceLoader* loader, unsigned long long bytesSent, unsigned long long totalBytesToBeSent)

{

    ASSERT(m_client);

    ASSERT_UNUSED(loader, loader == m_loader);

    m_client->didSendData(bytesSent, totalBytesToBeSent);

}

void DocumentThreadableLoader::didReceiveResponse(SubresourceLoader* loader, const ResourceResponse& response)

{

    ASSERT(m_client);

    ASSERT_UNUSED(loader, loader == m_loader);

    String accessControlErrorDescription;

    if (m_actualRequest) {

        if (!passesAccessControlCheck(response, m_options.allowCredentials, m_document->securityOrigin(), accessControlErrorDescription)) {

            preflightFailure(response.url(), accessControlErrorDescription);

            return;

        }

        OwnPtr<CrossOriginPreflightResultCacheItem> preflightResult(new CrossOriginPreflightResultCacheItem(m_options.allowCredentials));

        if (!preflightResult->parse(response, accessControlErrorDescription)

            || !preflightResult->allowsCrossOriginMethod(m_actualRequest->httpMethod(), accessControlErrorDescription)

            || !preflightResult->allowsCrossOriginHeaders(m_actualRequest->httpHeaderFields(), accessControlErrorDescription)) {

            preflightFailure(response.url(), accessControlErrorDescription);

            return;

        }

        CrossOriginPreflightResultCache::shared().appendEntry(m_document->securityOrigin()->toString(), m_actualRequest->url(), preflightResult.release());

    } else {

        if (!m_sameOriginRequest && m_options.crossOriginRequestPolicy == UseAccessControl) {

            if (!passesAccessControlCheck(response, m_options.allowCredentials, m_document->securityOrigin(), accessControlErrorDescription)) {

                m_client->didFail(ResourceError(errorDomainWebKitInternal, 0, response.url().string(), accessControlErrorDescription));

                return;

            }

        }

        m_client->didReceiveResponse(response);

    }

}

void DocumentThreadableLoader::didReceiveData(SubresourceLoader* loader, const char* data, int lengthReceived)

{

    ASSERT(m_client);

    ASSERT_UNUSED(loader, loader == m_loader);

    // Ignore response body of preflight requests.

    if (m_actualRequest)

        return;

    m_client->didReceiveData(data, lengthReceived);

}

void DocumentThreadableLoader::didFinishLoading(SubresourceLoader* loader)

{

    ASSERT(loader == m_loader);

    ASSERT(m_client);

    didFinishLoading(loader->identifier());

}

void DocumentThreadableLoader::didFinishLoading(unsigned long identifier)

{

    if (m_actualRequest) {

        ASSERT(!m_sameOriginRequest);

        ASSERT(m_options.crossOriginRequestPolicy == UseAccessControl);

        preflightSuccess();

    } else

        m_client->didFinishLoading(identifier);

}

void DocumentThreadableLoader::didFail(SubresourceLoader* loader, const ResourceError& error)

{

    ASSERT(m_client);

    // m_loader may be null if we arrive here via SubresourceLoader::create in the ctor

    ASSERT_UNUSED(loader, loader == m_loader || !m_loader);

    m_client->didFail(error);

}

bool DocumentThreadableLoader::getShouldUseCredentialStorage(SubresourceLoader* loader, bool& shouldUseCredentialStorage)

{

    ASSERT_UNUSED(loader, loader == m_loader || !m_loader);

    if (!m_options.allowCredentials) {

        shouldUseCredentialStorage = false;

        return true;

    }

    return false; // Only FrameLoaderClient can ultimately permit credential use.

}

void DocumentThreadableLoader::didReceiveAuthenticationChallenge(SubresourceLoader* loader, const AuthenticationChallenge& challenge)

{

    ASSERT(loader == m_loader);

    // Users are not prompted for credentials for cross-origin requests.

    if (!m_sameOriginRequest) {

#if PLATFORM(MAC) || USE(CFNETWORK) || USE(CURL)

        loader->handle()->receivedRequestToContinueWithoutCredential(challenge);

#else

        // These platforms don't provide a way to continue without credentials, cancel the load altogether.

        UNUSED_PARAM(challenge);

        RefPtr<DocumentThreadableLoader> protect(this);

        m_client->didFail(loader->blockedError());

        cancel();

#endif

    }

}

void DocumentThreadableLoader::receivedCancellation(SubresourceLoader* loader, const AuthenticationChallenge& challenge)

{

    ASSERT(m_client);

    ASSERT_UNUSED(loader, loader == m_loader);

    m_client->didReceiveAuthenticationCancellation(challenge.failureResponse());

}

void DocumentThreadableLoader::preflightSuccess()

{

    OwnPtr<ResourceRequest> actualRequest;

    actualRequest.swap(m_actualRequest);

    // It should be ok to skip the security check since we already asked about the preflight request.

    loadRequest(*actualRequest, SkipSecurityCheck);

}

void DocumentThreadableLoader::preflightFailure(const String& url, const String& errorDescription)

{

    m_actualRequest = 0; // Prevent didFinishLoading() from bypassing access check.

    m_client->didFail(ResourceError(errorDomainWebKitInternal, 0, url, errorDescription));

}

void DocumentThreadableLoader::loadRequest(const ResourceRequest& request, SecurityCheckPolicy securityCheck)

{

    // Any credential should have been removed from the cross-site requests.

    const KURL& requestURL = request.url();

    ASSERT(m_sameOriginRequest || requestURL.user().isEmpty());

    ASSERT(m_sameOriginRequest || requestURL.pass().isEmpty());

    if (m_async) {

        // Don't sniff content or send load callbacks for the preflight request.

        bool sendLoadCallbacks = m_options.sendLoadCallbacks && !m_actualRequest;

        bool sniffContent = m_options.sniffContent && !m_actualRequest;

        // Clear the loader so that any callbacks from SubresourceLoader::create will not have the old loader.

        m_loader = 0;

        m_loader = SubresourceLoader::create(m_document->frame(), this, request, securityCheck, sendLoadCallbacks, sniffContent);

        return;

    }

    // FIXME: ThreadableLoaderOptions.sniffContent is not supported for synchronous requests.

    StoredCredentials storedCredentials = m_options.allowCredentials ? AllowStoredCredentials : DoNotAllowStoredCredentials;

    Vector<char> data;

    ResourceError error;

    ResourceResponse response;

    unsigned long identifier = std::numeric_limits<unsigned long>::max();

    if (m_document->frame())

        identifier = m_document->frame()->loader()->loadResourceSynchronously(request, storedCredentials, error, response, data);

    // No exception for file:/// resources, see <rdar://problem/4962298>.

    // Also, if we have an HTTP response, then it wasn't a network error in fact.

    if (!error.isNull() && !requestURL.isLocalFile() && response.httpStatusCode() <= 0) {

        m_client->didFail(error);

        return;

    }

    // FIXME: FrameLoader::loadSynchronously() does not tell us whether a redirect happened or not, so we guess by comparing the

    // request and response URLs. This isn't a perfect test though, since a server can serve a redirect to the same URL that was

    // requested. Also comparing the request and response URLs as strings will fail if the requestURL still has its credentials.

    if (requestURL != response.url() && !isAllowedRedirect(response.url())) {

        m_client->didFailRedirectCheck();

        return;

    }

    didReceiveResponse(0, response);

    const char* bytes = static_cast<const char*>(data.data());

    int len = static_cast<int>(data.size());

    didReceiveData(0, bytes, len);

    didFinishLoading(identifier);

}

bool DocumentThreadableLoader::isAllowedRedirect(const KURL& url)

{

    if (m_options.crossOriginRequestPolicy == AllowCrossOriginRequests)

        return true;

    // FIXME: We need to implement access control for each redirect. This will require some refactoring though, because the code

    // that processes redirects doesn't know about access control and expects a synchronous answer from its client about whether

    // a redirect should proceed.

    return m_sameOriginRequest && m_document->securityOrigin()->canRequest(url);

}

} // namespace WebCore