/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 nsDocLoader_h__
#define nsDocLoader_h__

#include "nsIDocumentLoader.h"
#include "nsIWebProgress.h"
#include "nsIWebProgressListener.h"
#include "nsIRequestObserver.h"
#include "nsWeakReference.h"
#include "nsILoadGroup.h"
#include "nsCOMArray.h"
#include "nsTObserverArray.h"
#include "nsString.h"
#include "nsIChannel.h"
#include "nsIProgressEventSink.h"
#include "nsIInterfaceRequestor.h"
#include "nsIInterfaceRequestorUtils.h"
#include "nsIChannelEventSink.h"
#include "nsISupportsPriority.h"
#include "nsCOMPtr.h"
#include "PLDHashTable.h"
#include "nsCycleCollectionParticipant.h"

#include "mozilla/LinkedList.h"
#include "mozilla/UniquePtr.h"

namespace mozilla {
namespace dom {
class BrowserBridgeChild;
class BrowsingContext;
}  // namespace dom
}  // namespace mozilla

/****************************************************************************
 * nsDocLoader implementation...
 ****************************************************************************/

#define NS_THIS_DOCLOADER_IMPL_CID                   \
  { /* b4ec8387-98aa-4c08-93b6-6d23069c06f2 */       \
    0xb4ec8387, 0x98aa, 0x4c08, {                    \
      0x93, 0xb6, 0x6d, 0x23, 0x06, 0x9c, 0x06, 0xf2 \
    }                                                \
  }

class nsDocLoader : public nsIDocumentLoader,
                    public nsIRequestObserver,
                    public nsSupportsWeakReference,
                    public nsIProgressEventSink,
                    public nsIWebProgress,
                    public nsIInterfaceRequestor,
                    public nsIChannelEventSink,
                    public nsISupportsPriority {
 public:
  using BrowserBridgeChild = mozilla::dom::BrowserBridgeChild;

  NS_DECLARE_STATIC_IID_ACCESSOR(NS_THIS_DOCLOADER_IMPL_CID)

  nsDocLoader();

  [[nodiscard]] virtual nsresult Init();
  [[nodiscard]] nsresult InitWithBrowsingContext(
      mozilla::dom::BrowsingContext* aBrowsingContext);

  static already_AddRefed<nsDocLoader> GetAsDocLoader(nsISupports* aSupports);
  // Needed to deal with ambiguous inheritance from nsISupports...
  static nsISupports* GetAsSupports(nsDocLoader* aDocLoader) {
    return static_cast<nsIDocumentLoader*>(aDocLoader);
  }

  // Add aDocLoader as a child to the docloader service.
  [[nodiscard]] static nsresult AddDocLoaderAsChildOfRoot(
      nsDocLoader* aDocLoader);

  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(nsDocLoader, nsIDocumentLoader)

  NS_DECL_NSIDOCUMENTLOADER

  // nsIProgressEventSink
  NS_DECL_NSIPROGRESSEVENTSINK

  // nsIRequestObserver methods: (for observing the load group)
  NS_DECL_NSIREQUESTOBSERVER
  NS_DECL_NSIWEBPROGRESS

  NS_DECL_NSIINTERFACEREQUESTOR
  NS_DECL_NSICHANNELEVENTSINK
  NS_DECL_NSISUPPORTSPRIORITY;  // semicolon for clang-format bug 1629756

  // Implementation specific methods...

  // Remove aChild from our childlist.  This nulls out the child's mParent
  // pointer.
  [[nodiscard]] nsresult RemoveChildLoader(nsDocLoader* aChild);

  // Add aChild to our child list.  This will set aChild's mParent pointer to
  // |this|.
  [[nodiscard]] nsresult AddChildLoader(nsDocLoader* aChild);
  nsDocLoader* GetParent() const { return mParent; }

  struct nsListenerInfo {
    nsListenerInfo(nsIWeakReference* aListener, unsigned long aNotifyMask)
        : mWeakListener(aListener), mNotifyMask(aNotifyMask) {}

    // Weak pointer for the nsIWebProgressListener...
    nsWeakPtr mWeakListener;

    // Mask indicating which notifications the listener wants to receive.
    unsigned long mNotifyMask;
  };

  /**
   * Fired when a security change occurs due to page transitions,
   * or end document load. This interface should be called by
   * a security package (eg Netscape Personal Security Manager)
   * to notify nsIWebProgressListeners that security state has
   * changed. State flags are in nsIWebProgressListener.idl
   */
  void OnSecurityChange(nsISupports* aContext, uint32_t aState);

  void SetDocumentOpenedButNotLoaded() { mDocumentOpenedButNotLoaded = true; }

  bool TreatAsBackgroundLoad();

  void SetFakeOnLoadDispatched() { mHasFakeOnLoadDispatched = true; };

  bool HasFakeOnLoadDispatched() { return mHasFakeOnLoadDispatched; };

  void ResetToFirstLoad() {
    mHasFakeOnLoadDispatched = false;
    mIsReadyToHandlePostMessage = false;
    mTreatAsBackgroundLoad = false;
  };

  // Inform a parent docloader that a BrowserBridgeChild has been created for
  // an OOP sub-document.
  // (This is the OOP counterpart to ChildEnteringOnload below.)
  void OOPChildLoadStarted(BrowserBridgeChild* aChild) {
    MOZ_DIAGNOSTIC_ASSERT(!mOOPChildrenLoading.Contains(aChild));
    mOOPChildrenLoading.AppendElement(aChild);
  }

  // Inform a parent docloader that the BrowserBridgeChild for one of its
  // OOP sub-documents is done calling its onload handler.
  // (This is the OOP counterpart to ChildDoneWithOnload below.)
  void OOPChildLoadDone(BrowserBridgeChild* aChild) {
    // aChild will not be in the list if nsDocLoader::Stop() was called, since
    // that clears mOOPChildrenLoading.  It also dispatches the 'load' event,
    // so we don't need to call DocLoaderIsEmpty in that case.
    if (mOOPChildrenLoading.RemoveElement(aChild)) {
      DocLoaderIsEmpty(true);
    }
  }

  uint32_t ChildCount() const { return mChildList.Length(); }

 protected:
  virtual ~nsDocLoader();

  [[nodiscard]] virtual nsresult SetDocLoaderParent(nsDocLoader* aLoader);

  bool IsBusy();

  void SetBackgroundLoadIframe();

  void Destroy();
  virtual void DestroyChildren();

  nsIDocumentLoader* ChildAt(int32_t i) {
    return mChildList.SafeElementAt(i, nullptr);
  }

  void FireOnProgressChange(nsDocLoader* aLoadInitiator, nsIRequest* request,
                            int64_t aProgress, int64_t aProgressMax,
                            int64_t aProgressDelta, int64_t aTotalProgress,
                            int64_t aMaxTotalProgress);

  // This should be at least 2 long since we'll generally always
  // have the current page and the global docloader on the ancestor
  // list.  But to deal with frames it's better to make it a bit
  // longer, and it's always a stack temporary so there's no real
  // reason not to.
  typedef AutoTArray<RefPtr<nsDocLoader>, 8> WebProgressList;
  void GatherAncestorWebProgresses(WebProgressList& aList);

  void FireOnStateChange(nsIWebProgress* aProgress, nsIRequest* request,
                         int32_t aStateFlags, nsresult aStatus);

  // The guts of FireOnStateChange, but does not call itself on our ancestors.
  // The arguments that are const are const so that we can detect cases when
  // DoFireOnStateChange wants to propagate changes to the next web progress
  // at compile time.  The ones that are not, are references so that such
  // changes can be propagated.
  void DoFireOnStateChange(nsIWebProgress* const aProgress,
                           nsIRequest* const request, int32_t& aStateFlags,
                           const nsresult aStatus);

  void FireOnStatusChange(nsIWebProgress* aWebProgress, nsIRequest* aRequest,
                          nsresult aStatus, const char16_t* aMessage);

  void FireOnLocationChange(nsIWebProgress* aWebProgress, nsIRequest* aRequest,
                            nsIURI* aUri, uint32_t aFlags);

  [[nodiscard]] bool RefreshAttempted(nsIWebProgress* aWebProgress,
                                      nsIURI* aURI, int32_t aDelay,
                                      bool aSameURI);

  // this function is overridden by the docshell, it is provided so that we
  // can pass more information about redirect state (the normal OnStateChange
  // doesn't get the new channel).
  // @param aRedirectFlags The flags being sent to OnStateChange that
  //                       indicate the type of redirect.
  // @param aStateFlags    The channel flags normally sent to OnStateChange.
  virtual void OnRedirectStateChange(nsIChannel* aOldChannel,
                                     nsIChannel* aNewChannel,
                                     uint32_t aRedirectFlags,
                                     uint32_t aStateFlags) {}

  void doStartDocumentLoad();
  void doStartURLLoad(nsIRequest* request, int32_t aExtraFlags);
  void doStopURLLoad(nsIRequest* request, nsresult aStatus);
  void doStopDocumentLoad(nsIRequest* request, nsresult aStatus);

  void NotifyDoneWithOnload(nsDocLoader* aParent);

  // Inform a parent docloader that aChild is about to call its onload
  // handler.
  [[nodiscard]] bool ChildEnteringOnload(nsIDocumentLoader* aChild) {
    // It's ok if we're already in the list -- we'll just be in there twice
    // and then the RemoveObject calls from ChildDoneWithOnload will remove
    // us.
    return mChildrenInOnload.AppendObject(aChild);
  }

  // Inform a parent docloader that aChild is done calling its onload
  // handler.
  void ChildDoneWithOnload(nsIDocumentLoader* aChild) {
    mChildrenInOnload.RemoveObject(aChild);
    DocLoaderIsEmpty(true);
  }

  // DocLoaderIsEmpty should be called whenever the docloader may be empty.
  // This method is idempotent and does nothing if the docloader is not in
  // fact empty.  This method _does_ make sure that layout is flushed if our
  // loadgroup has no active requests before checking for "real" emptiness if
  // aFlushLayout is true.
  // @param aOverrideStatus An optional status to use when notifying listeners
  // of the completed load, instead of using the load group's status.
  void DocLoaderIsEmpty(
      bool aFlushLayout,
      const mozilla::Maybe<nsresult>& aOverrideStatus = mozilla::Nothing());

 protected:
  struct nsStatusInfo : public mozilla::LinkedListElement<nsStatusInfo> {
    nsString mStatusMessage;
    nsresult mStatusCode;
    // Weak mRequest is ok; we'll be told if it decides to go away.
    nsIRequest* const mRequest;

    explicit nsStatusInfo(nsIRequest* aRequest)
        : mStatusCode(NS_ERROR_NOT_INITIALIZED), mRequest(aRequest) {
      MOZ_COUNT_CTOR(nsStatusInfo);
    }
    MOZ_COUNTED_DTOR(nsStatusInfo)
  };

  struct nsRequestInfo : public PLDHashEntryHdr {
    explicit nsRequestInfo(const void* key)
        : mKey(key),
          mCurrentProgress(0),
          mMaxProgress(0),
          mUploading(false),
          mLastStatus(nullptr) {
      MOZ_COUNT_CTOR(nsRequestInfo);
    }

    MOZ_COUNTED_DTOR(nsRequestInfo)

    nsIRequest* Request() {
      return static_cast<nsIRequest*>(const_cast<void*>(mKey));
    }

    const void* mKey;  // Must be first for the PLDHashTable stubs to work
    int64_t mCurrentProgress;
    int64_t mMaxProgress;
    bool mUploading;

    mozilla::UniquePtr<nsStatusInfo> mLastStatus;
  };

  static void RequestInfoHashInitEntry(PLDHashEntryHdr* entry, const void* key);
  static void RequestInfoHashClearEntry(PLDHashTable* table,
                                        PLDHashEntryHdr* entry);

  // IMPORTANT: The ownership implicit in the following member
  // variables has been explicitly checked and set using nsCOMPtr
  // for owning pointers and raw COM interface pointers for weak
  // (ie, non owning) references. If you add any members to this
  // class, please make the ownership explicit (pinkerton, scc).

  nsCOMPtr<nsIRequest> mDocumentRequest;  // [OWNER] ???compare with document

  nsDocLoader* mParent;  // [WEAK]

  typedef nsAutoTObserverArray<nsListenerInfo, 8> ListenerArray;
  ListenerArray mListenerInfoList;

  nsCOMPtr<nsILoadGroup> mLoadGroup;
  // We hold weak refs to all our kids
  nsTObserverArray<nsDocLoader*> mChildList;

  // The following member variables are related to the new nsIWebProgress
  // feedback interfaces that travis cooked up.
  int32_t mProgressStateFlags;

  int64_t mCurrentSelfProgress;
  int64_t mMaxSelfProgress;

  int64_t mCurrentTotalProgress;
  int64_t mMaxTotalProgress;

  PLDHashTable mRequestInfoHash;
  int64_t mCompletedTotalProgress;

  mozilla::LinkedList<nsStatusInfo> mStatusInfoList;

  /*
   * This flag indicates that the loader is loading a document.  It is set
   * from the call to LoadDocument(...) until the OnConnectionsComplete(...)
   * notification is fired...
   */
  bool mIsLoadingDocument;

  /* Flag to indicate that we're in the process of restoring a document. */
  bool mIsRestoringDocument;

  /* Flag to indicate that we're in the process of flushing layout
     under DocLoaderIsEmpty() and should not do another flush. */
  bool mDontFlushLayout;

  /* Flag to indicate whether we should consider ourselves as currently
     flushing layout for the purposes of IsBusy. For example, if Stop has
     been called then IsBusy should return false even if we are still
     flushing. */
  bool mIsFlushingLayout;

  bool mTreatAsBackgroundLoad;

 private:
  bool mHasFakeOnLoadDispatched;

  bool mIsReadyToHandlePostMessage;
  /**
   * This flag indicates that the loader is waiting for completion of
   * a document.open-triggered "document load".  This is set when
   * document.open() happens and sets up a new parser and cleared out
   * when we go to fire our load event or end up with a new document
   * channel.
   */
  bool mDocumentOpenedButNotLoaded;

  static const PLDHashTableOps sRequestInfoHashOps;

  // A list of kids that are in the middle of their onload calls and will let
  // us know once they're done.  We don't want to fire onload for "normal"
  // DocLoaderIsEmpty calls (those coming from requests finishing in our
  // loadgroup) unless this is empty.
  nsCOMArray<nsIDocumentLoader> mChildrenInOnload;

  // The OOP counterpart to mChildrenInOnload.
  // Not holding strong refs here since we don't actually use the BBCs.
  nsTArray<const BrowserBridgeChild*> mOOPChildrenLoading;

  int64_t GetMaxTotalProgress();

  nsresult AddRequestInfo(nsIRequest* aRequest);
  void RemoveRequestInfo(nsIRequest* aRequest);
  nsRequestInfo* GetRequestInfo(nsIRequest* aRequest) const;
  void ClearRequestInfoHash();
  int64_t CalculateMaxProgress();
  ///    void DumpChannelInfo(void);

  // used to clear our internal progress state between loads...
  void ClearInternalProgress();

  /**
   * Used to test whether we might need to fire a load event.  This
   * can happen when we have a document load going on, or when we've
   * had document.open() called and haven't fired the corresponding
   * load event yet.
   */
  bool IsBlockingLoadEvent() const {
    return mIsLoadingDocument || mDocumentOpenedButNotLoaded;
  }
};

NS_DEFINE_STATIC_IID_ACCESSOR(nsDocLoader, NS_THIS_DOCLOADER_IMPL_CID)

static inline nsISupports* ToSupports(nsDocLoader* aDocLoader) {
  return static_cast<nsIDocumentLoader*>(aDocLoader);
}

#endif /* nsDocLoader_h__ */