Source/core/loader/ThreadableLoader.h

/*
 * Copyright (C) 2009 Google Inc. All rights reserved.
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 * 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
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 * 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
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#ifndef ThreadableLoader_h
#define ThreadableLoader_h

#include "core/fetch/ResourceLoaderOptions.h"
#include "platform/CrossThreadCopier.h"
#include "wtf/Noncopyable.h"
#include "wtf/PassRefPtr.h"
#include "wtf/RefCounted.h"
#include "wtf/RefPtr.h"

namespace blink {

    class ResourceError;
    class ResourceRequest;
    class ResourceResponse;
    class ExecutionContext;
    class ThreadableLoaderClient;

    enum CrossOriginRequestPolicy {
        DenyCrossOriginRequests,
        UseAccessControl,
        AllowCrossOriginRequests
    };

    enum PreflightPolicy {
        ConsiderPreflight,
        ForcePreflight,
        PreventPreflight
    };

    enum ContentSecurityPolicyEnforcement {
        EnforceConnectSrcDirective,
        DoNotEnforceContentSecurityPolicy,
    };

    struct ThreadableLoaderOptions {
        ThreadableLoaderOptions()
            : preflightPolicy(ConsiderPreflight)
            , crossOriginRequestPolicy(DenyCrossOriginRequests)
            , contentSecurityPolicyEnforcement(EnforceConnectSrcDirective)
            , timeoutMilliseconds(0) { }

        // When adding members, CrossThreadThreadableLoaderOptionsData should
        // be updated.
        PreflightPolicy preflightPolicy; // If AccessControl is used, how to determine if a preflight is needed.
        CrossOriginRequestPolicy crossOriginRequestPolicy;
        AtomicString initiator;
        ContentSecurityPolicyEnforcement contentSecurityPolicyEnforcement;
        unsigned long timeoutMilliseconds;
    };

    // Encode AtomicString as String to cross threads.
    struct CrossThreadThreadableLoaderOptionsData {
        explicit CrossThreadThreadableLoaderOptionsData(const ThreadableLoaderOptions& options)
            : preflightPolicy(options.preflightPolicy)
            , crossOriginRequestPolicy(options.crossOriginRequestPolicy)
            , initiator(options.initiator.string().isolatedCopy())
            , contentSecurityPolicyEnforcement(options.contentSecurityPolicyEnforcement)
            , timeoutMilliseconds(options.timeoutMilliseconds) { }

        operator ThreadableLoaderOptions() const
        {
            ThreadableLoaderOptions options;
            options.preflightPolicy = preflightPolicy;
            options.crossOriginRequestPolicy = crossOriginRequestPolicy;
            options.initiator = AtomicString(initiator);
            options.contentSecurityPolicyEnforcement = contentSecurityPolicyEnforcement;
            options.timeoutMilliseconds = timeoutMilliseconds;
            return options;
        }

        PreflightPolicy preflightPolicy;
        CrossOriginRequestPolicy crossOriginRequestPolicy;
        String initiator;
        ContentSecurityPolicyEnforcement contentSecurityPolicyEnforcement;
        unsigned long timeoutMilliseconds;
    };

    template<> struct CrossThreadCopierBase<false, false, false, ThreadableLoaderOptions> {
        typedef CrossThreadThreadableLoaderOptionsData Type;
        static Type copy(const ThreadableLoaderOptions& options)
        {
            return CrossThreadThreadableLoaderOptionsData(options);
        }
    };

    // Useful for doing loader operations from any thread (not threadsafe,
    // just able to run on threads other than the main thread).
    class ThreadableLoader : public RefCounted<ThreadableLoader> {
        WTF_MAKE_NONCOPYABLE(ThreadableLoader);
    public:
        // ThreadableLoaderOptions argument configures this ThreadableLoader's
        // behavior.
        //
        // ResourceLoaderOptions argument will be passed to the FetchRequest
        // that this ThreadableLoader creates. It can be altered e.g. when
        // redirect happens.
        static void loadResourceSynchronously(ExecutionContext&, const ResourceRequest&, ThreadableLoaderClient&, const ThreadableLoaderOptions&, const ResourceLoaderOptions&);
        static PassRefPtr<ThreadableLoader> create(ExecutionContext&, ThreadableLoaderClient*, const ResourceRequest&, const ThreadableLoaderOptions&, const ResourceLoaderOptions&);

        // A ThreadableLoader may have a timeout specified. It is possible, in some cases, for
        // the timeout to be overridden after the request is sent (for example, XMLHttpRequests
        // may override their timeout setting after sending).
        //
        // Set a new timeout relative to the time the request started, in milliseconds.
        virtual void overrideTimeout(unsigned long timeoutMilliseconds) = 0;

        virtual void cancel() = 0;

        virtual ~ThreadableLoader() { }

    protected:
        ThreadableLoader() { }
    };

} // namespace blink

#endif // ThreadableLoader_h