gecko-dev/docshell/shistory/nsSHistory.h

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 nsSHistory_h
#define nsSHistory_h
#include "nsCOMPtr.h"
#include "nsExpirationTracker.h"
#include "nsIPartialSHistoryListener.h"
#include "nsISHistory.h"
#include "nsISHistoryInternal.h"
#include "nsISimpleEnumerator.h"
#include "nsIWebNavigation.h"
#include "nsSHEntryShared.h"
#include "nsTObserverArray.h"
#include "nsWeakReference.h"
#include "mozilla/LinkedList.h"
#include "mozilla/UniquePtr.h"
class nsIDocShell;
class nsSHEnumerator;
class nsSHistoryObserver;
class nsISHEntry;
class nsISHTransaction;
class nsSHistory final : public mozilla::LinkedListElement<nsSHistory>,
public nsISHistory,
public nsISHistoryInternal,
public nsIWebNavigation,
public nsSupportsWeakReference
{
public:
// The timer based history tracker is used to evict bfcache on expiration.
class HistoryTracker final : public nsExpirationTracker<nsSHEntryShared, 3>
{
public:
explicit HistoryTracker(nsSHistory* aSHistory,
uint32_t aTimeout,
nsIEventTarget* aEventTarget)
: nsExpirationTracker(1000 * aTimeout / 2, "HistoryTracker", aEventTarget)
{
MOZ_ASSERT(aSHistory);
mSHistory = aSHistory;
}
protected:
virtual void NotifyExpired(nsSHEntryShared* aObj)
{
RemoveObject(aObj);
mSHistory->EvictExpiredContentViewerForEntry(aObj);
}
private:
// HistoryTracker is owned by nsSHistory; it always outlives HistoryTracker
// so it's safe to use raw pointer here.
nsSHistory* mSHistory;
};
nsSHistory();
NS_DECL_ISUPPORTS
NS_DECL_NSISHISTORY
NS_DECL_NSISHISTORYINTERNAL
NS_DECL_NSIWEBNAVIGATION
// One time initialization method called upon docshell module construction
static nsresult Startup();
static void Shutdown();
static void UpdatePrefs();
// Max number of total cached content viewers. If the pref
// browser.sessionhistory.max_total_viewers is negative, then
// this value is calculated based on the total amount of memory.
// Otherwise, it comes straight from the pref.
static uint32_t GetMaxTotalViewers() { return sHistoryMaxTotalViewers; }
private:
virtual ~nsSHistory();
friend class nsSHEnumerator;
friend class nsSHistoryObserver;
nsresult GetTransactionAtIndex(int32_t aIndex, nsISHTransaction** aResult);
nsresult LoadDifferingEntries(nsISHEntry* aPrevEntry, nsISHEntry* aNextEntry,
nsIDocShell* aRootDocShell, long aLoadType,
bool& aDifferenceFound);
nsresult InitiateLoad(nsISHEntry* aFrameEntry, nsIDocShell* aFrameDS,
long aLoadType);
nsresult LoadEntry(int32_t aIndex, long aLoadType, uint32_t aHistCmd);
#ifdef DEBUG
nsresult PrintHistory();
#endif
// Find the transaction for a given bfcache entry. It only looks up between
// the range where alive viewers may exist (i.e nsISHistory::VIEWER_WINDOW).
nsresult FindTransactionForBFCache(nsIBFCacheEntry* aEntry,
nsISHTransaction** aResult,
int32_t* aResultIndex);
// Evict content viewers in this window which don't lie in the "safe" range
// around aIndex.
void EvictOutOfRangeWindowContentViewers(int32_t aIndex);
void EvictContentViewerForTransaction(nsISHTransaction* aTrans);
static void GloballyEvictContentViewers();
static void GloballyEvictAllContentViewers();
// Calculates a max number of total
// content viewers to cache, based on amount of total memory
static uint32_t CalcMaxTotalViewers();
nsresult LoadNextPossibleEntry(int32_t aNewIndex, long aLoadType,
uint32_t aHistCmd);
// aIndex is the index of the transaction which may be removed.
// If aKeepNext is true, aIndex is compared to aIndex + 1,
// otherwise comparison is done to aIndex - 1.
bool RemoveDuplicate(int32_t aIndex, bool aKeepNext);
// Track all bfcache entries and evict on expiration.
mozilla::UniquePtr<HistoryTracker> mHistoryTracker;
nsCOMPtr<nsISHTransaction> mListRoot;
int32_t mIndex;
int32_t mLength;
int32_t mRequestedIndex;
// The number of entries before this session history object.
int32_t mGlobalIndexOffset;
// The number of entries after this session history object.
int32_t mEntriesInFollowingPartialHistories;
// Session History listeners
nsAutoTObserverArray<nsWeakPtr, 2> mListeners;
// Partial session history listener
nsWeakPtr mPartialHistoryListener;
// Weak reference. Do not refcount this.
nsIDocShell* mRootDocShell;
// Set to true if attached to a grouped session history.
bool mIsPartial;
// Max viewers allowed total, across all SHistory objects
static int32_t sHistoryMaxTotalViewers;
};
class nsSHEnumerator : public nsISimpleEnumerator
{
public:
NS_DECL_ISUPPORTS
NS_DECL_NSISIMPLEENUMERATOR
explicit nsSHEnumerator(nsSHistory* aHistory);
protected:
friend class nsSHistory;
virtual ~nsSHEnumerator();
private:
int32_t mIndex;
nsSHistory* mSHistory;
};
#endif /* nsSHistory */