/*

 * Copyright (C) 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.

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``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 COMPUTER, INC. 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"

#include "CrossOriginAccessControl.h"

#include "AtomicString.h"

#include "HTTPParsers.h"

#include "ResourceResponse.h"

#include "SecurityOrigin.h"

#include <wtf/Threading.h>

namespace WebCore {

bool isOnAccessControlSimpleRequestMethodWhitelist(const String& method)

{

    return method == "GET" || method == "HEAD" || method == "POST";

}

bool isOnAccessControlSimpleRequestHeaderWhitelist(const String& name, const String& value)

{

    if (equalIgnoringCase(name, "accept") || equalIgnoringCase(name, "accept-language") || equalIgnoringCase(name, "content-language"))

        return true;

    // Preflight is required for MIME types that can not be sent via form submission.

    if (equalIgnoringCase(name, "content-type")) {

        String mimeType = extractMIMETypeFromMediaType(value);

        return equalIgnoringCase(mimeType, "application/x-www-form-urlencoded")

            || equalIgnoringCase(mimeType, "multipart/form-data")

            || equalIgnoringCase(mimeType, "text/plain");

    }

    return false;

}

bool isSimpleCrossOriginAccessRequest(const String& method, const HTTPHeaderMap& headerMap)

{

    if (!isOnAccessControlSimpleRequestMethodWhitelist(method))

        return false;

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

    for (HTTPHeaderMap::const_iterator it = headerMap.begin(); it != end; ++it) {

        if (!isOnAccessControlSimpleRequestHeaderWhitelist(it->first, it->second))

            return false;

    }

    return true;

}

typedef HashSet<String, CaseFoldingHash> HTTPHeaderSet;

static HTTPHeaderSet* createAllowedCrossOriginResponseHeadersSet()

{

    HTTPHeaderSet* headerSet = new HashSet<String, CaseFoldingHash>;

    headerSet->add("cache-control");

    headerSet->add("content-language");

    headerSet->add("content-type");

    headerSet->add("expires");

    headerSet->add("last-modified");

    headerSet->add("pragma");

    return headerSet;

}

bool isOnAccessControlResponseHeaderWhitelist(const String& name)

{

    AtomicallyInitializedStatic(HTTPHeaderSet*, allowedCrossOriginResponseHeaders = createAllowedCrossOriginResponseHeadersSet());

    return allowedCrossOriginResponseHeaders->contains(name);

}

bool passesAccessControlCheck(const ResourceResponse& response, bool includeCredentials, SecurityOrigin* securityOrigin, String& errorDescription)

{

    // A wildcard Access-Control-Allow-Origin can not be used if credentials are to be sent,

    // even with Access-Control-Allow-Credentials set to true.

    const String& accessControlOriginString = response.httpHeaderField("Access-Control-Allow-Origin");

    if (accessControlOriginString == "*" && !includeCredentials)

        return true;

    if (securityOrigin->isUnique()) {

        errorDescription = "Cannot make any requests from " + securityOrigin->toString() + ".";

        return false;

    }

    // FIXME: Access-Control-Allow-Origin can contain a list of origins.

    RefPtr<SecurityOrigin> accessControlOrigin = SecurityOrigin::createFromString(accessControlOriginString);

    if (!accessControlOrigin->isSameSchemeHostPort(securityOrigin)) {

        errorDescription = (accessControlOriginString == "*") ? "Cannot use wildcard in Access-Control-Allow-Origin when credentials flag is true."

            : "Origin " + securityOrigin->toString() + " is not allowed by Access-Control-Allow-Origin.";

        return false;

    }

    if (includeCredentials) {

        const String& accessControlCredentialsString = response.httpHeaderField("Access-Control-Allow-Credentials");

        if (accessControlCredentialsString != "true") {

            errorDescription = "Credentials flag is true, but Access-Control-Allow-Credentials is not \"true\".";

            return false;

        }

    }

    return true;

}

} // namespace WebCore