/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef nsPrefetchService_h__
#define nsPrefetchService_h__

#include "nsCPrefetchService.h"
#include "nsIObserver.h"
#include "nsIInterfaceRequestor.h"
#include "nsIChannelEventSink.h"
#include "nsIRedirectResultListener.h"
#include "nsIWebProgressListener.h"
#include "nsIStreamListener.h"
#include "nsIChannel.h"
#include "nsIURI.h"
#include "nsWeakReference.h"
#include "nsCOMPtr.h"
#include "nsAutoPtr.h"
#include "mozilla/Attributes.h"
#include <deque>

class nsPrefetchService;
class nsPrefetchNode;

//-----------------------------------------------------------------------------
// nsPrefetchService
//-----------------------------------------------------------------------------

class nsPrefetchService final : public nsIPrefetchService
                              , public nsIWebProgressListener
                              , public nsIObserver
                              , public nsSupportsWeakReference
{
public:
    NS_DECL_ISUPPORTS
    NS_DECL_NSIPREFETCHSERVICE
    NS_DECL_NSIWEBPROGRESSLISTENER
    NS_DECL_NSIOBSERVER

    nsPrefetchService();

    nsresult Init();
    void     RemoveNodeAndMaybeStartNextPrefetchURI(nsPrefetchNode *aFinished);
    void     ProcessNextPrefetchURI();

    void NotifyLoadRequested(nsPrefetchNode *node);
    void NotifyLoadCompleted(nsPrefetchNode *node);
    void DispatchEvent(nsPrefetchNode *node, bool aSuccess);

private:
    ~nsPrefetchService();

    nsresult Prefetch(nsIURI *aURI,
                      nsIURI *aReferrerURI,
                      nsINode *aSource,
                      bool aExplicit);

    nsresult Preload(nsIURI *aURI,
                     nsIURI *aReferrerURI,
                     nsINode *aSource,
                     nsContentPolicyType aPolicyType);

    void     AddProgressListener();
    void     RemoveProgressListener();
    nsresult EnqueueURI(nsIURI *aURI, nsIURI *aReferrerURI,
                        nsINode *aSource, nsPrefetchNode **node);
    void     EmptyPrefetchQueue();

    void     StartPrefetching();
    void     StopPrefetching();
    void     StopCurrentPrefetchsPreloads(bool aPreload);
    void     StopAll();
    nsresult CheckURIScheme(nsIURI *aURI, nsIURI *aReferrerURI);

    std::deque<RefPtr<nsPrefetchNode>> mPrefetchQueue;
    nsTArray<RefPtr<nsPrefetchNode>>   mCurrentNodes;
    int32_t                            mMaxParallelism;
    int32_t                            mStopCount;
    bool                               mHaveProcessed;
    bool                               mPrefetchDisabled;
    bool                               mPreloadDisabled;

    // In usual case prefetch does not start until all normal loads are done.
    // Aggressive mode ignores normal loads and just start prefetch ASAP.
    // It's mainly for testing purpose and discoraged for normal use;
    // see https://bugzilla.mozilla.org/show_bug.cgi?id=1281415 for details.
    bool                               mAggressive;
};

//-----------------------------------------------------------------------------
// nsPreFetchingNode
//-----------------------------------------------------------------------------

class nsPrefetchNode final : public nsIStreamListener
                           , public nsIInterfaceRequestor
                           , public nsIChannelEventSink
                           , public nsIRedirectResultListener
{
public:
    NS_DECL_ISUPPORTS
    NS_DECL_NSIREQUESTOBSERVER
    NS_DECL_NSISTREAMLISTENER
    NS_DECL_NSIINTERFACEREQUESTOR
    NS_DECL_NSICHANNELEVENTSINK
    NS_DECL_NSIREDIRECTRESULTLISTENER

    nsPrefetchNode(nsPrefetchService *aPrefetchService,
                   nsIURI *aURI,
                   nsIURI *aReferrerURI,
                   nsINode *aSource,
                   nsContentPolicyType aPolicyType,
                   bool aPreload);

    nsresult OpenChannel();
    nsresult CancelChannel(nsresult error);

    nsCOMPtr<nsIURI>                      mURI;
    nsCOMPtr<nsIURI>                      mReferrerURI;
    nsTArray<nsCOMPtr<nsIWeakReference>>  mSources;

    // The policy type to be used for fetching the resource.
    nsContentPolicyType                   mPolicyType;
    // nsPrefetchNode is used for prefetching and preloading resource.
    // mPreload is true if a resource is preloaded. Preloads and
    // prefetches are fetched in different phases (during load and
    // after a page load), therefore we need to distinguish them.
    bool                                  mPreload;

private:
    ~nsPrefetchNode() {}

    RefPtr<nsPrefetchService>   mService;
    nsCOMPtr<nsIChannel>        mChannel;
    nsCOMPtr<nsIChannel>        mRedirectChannel;
    int64_t                     mBytesRead;
    bool                        mShouldFireLoadEvent;
};

#endif // !nsPrefetchService_h__
