The Tor Browser: docshell/shistory/src/nsSHistory.cpp@925c144e1f1f

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

     2  *

     3  * This Source Code Form is subject to the terms of the Mozilla Public

     4  * License, v. 2.0. If a copy of the MPL was not distributed with this

     5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     7 // Local Includes

     8 #include "nsSHistory.h"

     9 #include <algorithm>

    11 // Helper Classes

    12 #include "mozilla/Preferences.h"

    14 // Interfaces Needed

    15 #include "nsILayoutHistoryState.h"

    16 #include "nsIDocShell.h"

    17 #include "nsIDocShellLoadInfo.h"

    18 #include "nsISHContainer.h"

    19 #include "nsIDocShellTreeItem.h"

    20 #include "nsIURI.h"

    21 #include "nsIContentViewer.h"

    22 #include "nsICacheService.h"

    23 #include "nsIObserverService.h"

    24 #include "prclist.h"

    25 #include "mozilla/Services.h"

    26 #include "nsTArray.h"

    27 #include "nsCOMArray.h"

    28 #include "nsDocShell.h"

    29 #include "mozilla/Attributes.h"

    30 #include "nsISHEntry.h"

    31 #include "nsISHTransaction.h"

    32 #include "nsISHistoryListener.h"

    33 #include "nsComponentManagerUtils.h"

    35 // For calculating max history entries and max cachable contentviewers

    36 #include "prsystem.h"

    37 #include "mozilla/MathAlgorithms.h"

    39 using namespace mozilla;

    41 #define PREF_SHISTORY_SIZE "browser.sessionhistory.max_entries"

    42 #define PREF_SHISTORY_MAX_TOTAL_VIEWERS "browser.sessionhistory.max_total_viewers"

    44 static const char* kObservedPrefs[] = {

    45   PREF_SHISTORY_SIZE,

    46   PREF_SHISTORY_MAX_TOTAL_VIEWERS,

    47   nullptr

    48 };

    50 static int32_t  gHistoryMaxSize = 50;

    51 // Max viewers allowed per SHistory objects

    52 static const int32_t  gHistoryMaxViewers = 3;

    53 // List of all SHistory objects, used for content viewer cache eviction

    54 static PRCList gSHistoryList;

    55 // Max viewers allowed total, across all SHistory objects - negative default

    56 // means we will calculate how many viewers to cache based on total memory

    57 int32_t nsSHistory::sHistoryMaxTotalViewers = -1;

    59 // A counter that is used to be able to know the order in which

    60 // entries were touched, so that we can evict older entries first.

    61 static uint32_t gTouchCounter = 0;

    63 #ifdef PR_LOGGING

    65 static PRLogModuleInfo*

    66 GetSHistoryLog()

    67 {

    68   static PRLogModuleInfo *sLog;

    69   if (!sLog)

    70     sLog = PR_NewLogModule("nsSHistory");

    71   return sLog;

    72 }

    73 #define LOG(format) PR_LOG(GetSHistoryLog(), PR_LOG_DEBUG, format)

    75 // This macro makes it easier to print a log message which includes a URI's

    76 // spec.  Example use:

    77 //

    78 //  nsIURI *uri = [...];

    79 //  LOG_SPEC(("The URI is %s.", _spec), uri);

    80 //

    81 #define LOG_SPEC(format, uri)                              \

    82   PR_BEGIN_MACRO                                           \

    83     if (PR_LOG_TEST(GetSHistoryLog(), PR_LOG_DEBUG)) {     \

    84       nsAutoCString _specStr(NS_LITERAL_CSTRING("(null)"));\

    85       if (uri) {                                           \

    86         uri->GetSpec(_specStr);                            \

    87       }                                                    \

    88       const char* _spec = _specStr.get();                  \

    89       LOG(format);                                         \

    90     }                                                      \

    91   PR_END_MACRO

    93 // This macro makes it easy to log a message including an SHEntry's URI.

    94 // For example:

    95 //

    96 //  nsCOMPtr<nsISHEntry> shentry = [...];

    97 //  LOG_SHENTRY_SPEC(("shentry %p has uri %s.", shentry.get(), _spec), shentry);

    98 //

    99 #define LOG_SHENTRY_SPEC(format, shentry)                  \

   100   PR_BEGIN_MACRO                                           \

   101     if (PR_LOG_TEST(GetSHistoryLog(), PR_LOG_DEBUG)) {     \

   102       nsCOMPtr<nsIURI> uri;                                \

   103       shentry->GetURI(getter_AddRefs(uri));                \

   104       LOG_SPEC(format, uri);                               \

   105     }                                                      \

   106   PR_END_MACRO

   108 #else // !PR_LOGGING

   110 #define LOG(format)

   111 #define LOG_SPEC(format, uri)

   112 #define LOG_SHENTRY_SPEC(format, shentry)

   114 #endif // PR_LOGGING

   116 // Iterates over all registered session history listeners.

   117 #define ITERATE_LISTENERS(body)                            \

   118   PR_BEGIN_MACRO                                           \

   119   {                                                        \

   120     nsAutoTObserverArray<nsWeakPtr, 2>::EndLimitedIterator \

   121       iter(mListeners);                                    \

   122     while (iter.HasMore()) {                               \

   123       nsCOMPtr<nsISHistoryListener> listener =             \

   124         do_QueryReferent(iter.GetNext());                  \

   125       if (listener) {                                      \

   126         body                                               \

   127       }                                                    \

   128     }                                                      \

   129   }                                                        \

   130   PR_END_MACRO

   132 // Calls a given method on all registered session history listeners.

   133 #define NOTIFY_LISTENERS(method, args)                     \

   134   ITERATE_LISTENERS(                                       \

   135     listener->method args;                                 \

   136   );

   138 // Calls a given method on all registered session history listeners.

   139 // Listeners may return 'false' to cancel an action so make sure that we

   140 // set the return value to 'false' if one of the listeners wants to cancel.

   141 #define NOTIFY_LISTENERS_CANCELABLE(method, retval, args)  \

   142   PR_BEGIN_MACRO                                           \

   143   {                                                        \

   144     bool canceled = false;                                 \

   145     retval = true;                                         \

   146     ITERATE_LISTENERS(                                     \

   147       listener->method args;                               \

   148       if (!retval) {                                       \

   149         canceled = true;                                   \

   150       }                                                    \

   151     );                                                     \

   152     if (canceled) {                                        \

   153       retval = false;                                      \

   154     }                                                      \

   155   }                                                        \

   156   PR_END_MACRO

   158 enum HistCmd{

   159   HIST_CMD_BACK,

   160   HIST_CMD_FORWARD,

   161   HIST_CMD_GOTOINDEX,

   162   HIST_CMD_RELOAD

   163 } ;

   165 //*****************************************************************************

   166 //***      nsSHistoryObserver

   167 //*****************************************************************************

   169 class nsSHistoryObserver MOZ_FINAL : public nsIObserver

   170 {

   172 public:

   173   NS_DECL_ISUPPORTS

   174   NS_DECL_NSIOBSERVER

   176   nsSHistoryObserver() {}

   178 protected:

   179   ~nsSHistoryObserver() {}

   180 };

   182 static nsSHistoryObserver* gObserver = nullptr;

   184 NS_IMPL_ISUPPORTS(nsSHistoryObserver, nsIObserver)

   186 NS_IMETHODIMP

   187 nsSHistoryObserver::Observe(nsISupports *aSubject, const char *aTopic,

   188                             const char16_t *aData)

   189 {

   190   if (!strcmp(aTopic, NS_PREFBRANCH_PREFCHANGE_TOPIC_ID)) {

   191     nsSHistory::UpdatePrefs();

   192     nsSHistory::GloballyEvictContentViewers();

   193   } else if (!strcmp(aTopic, NS_CACHESERVICE_EMPTYCACHE_TOPIC_ID) ||

   194              !strcmp(aTopic, "memory-pressure")) {

   195     nsSHistory::GloballyEvictAllContentViewers();

   196   }

   198   return NS_OK;

   199 }

   201 namespace {

   203 already_AddRefed<nsIContentViewer>

   204 GetContentViewerForTransaction(nsISHTransaction *aTrans)

   205 {

   206   nsCOMPtr<nsISHEntry> entry;

   207   aTrans->GetSHEntry(getter_AddRefs(entry));

   208   if (!entry) {

   209     return nullptr;

   210   }

   212   nsCOMPtr<nsISHEntry> ownerEntry;

   213   nsCOMPtr<nsIContentViewer> viewer;

   214   entry->GetAnyContentViewer(getter_AddRefs(ownerEntry),

   215                              getter_AddRefs(viewer));

   216   return viewer.forget();

   217 }

   219 void

   220 EvictContentViewerForTransaction(nsISHTransaction *aTrans)

   221 {

   222   nsCOMPtr<nsISHEntry> entry;

   223   aTrans->GetSHEntry(getter_AddRefs(entry));

   224   nsCOMPtr<nsIContentViewer> viewer;

   225   nsCOMPtr<nsISHEntry> ownerEntry;

   226   entry->GetAnyContentViewer(getter_AddRefs(ownerEntry),

   227                              getter_AddRefs(viewer));

   228   if (viewer) {

   229     NS_ASSERTION(ownerEntry,

   230                  "Content viewer exists but its SHEntry is null");

   232     LOG_SHENTRY_SPEC(("Evicting content viewer 0x%p for "

   233                       "owning SHEntry 0x%p at %s.",

   234                       viewer.get(), ownerEntry.get(), _spec), ownerEntry);

   236     // Drop the presentation state before destroying the viewer, so that

   237     // document teardown is able to correctly persist the state.

   238     ownerEntry->SetContentViewer(nullptr);

   239     ownerEntry->SyncPresentationState();

   240     viewer->Destroy();

   241   }

   242 }

   244 } // anonymous namespace

   246 //*****************************************************************************

   247 //***    nsSHistory: Object Management

   248 //*****************************************************************************

   250 nsSHistory::nsSHistory() : mListRoot(nullptr), mIndex(-1), mLength(0), mRequestedIndex(-1)

   251 {

   252   // Add this new SHistory object to the list

   253   PR_APPEND_LINK(this, &gSHistoryList);

   254 }

   257 nsSHistory::~nsSHistory()

   258 {

   259   // Remove this SHistory object from the list

   260   PR_REMOVE_LINK(this);

   261 }

   263 //*****************************************************************************

   264 //    nsSHistory: nsISupports

   265 //*****************************************************************************

   267 NS_IMPL_ADDREF(nsSHistory)

   268 NS_IMPL_RELEASE(nsSHistory)

   270 NS_INTERFACE_MAP_BEGIN(nsSHistory)

   271    NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsISHistory)

   272    NS_INTERFACE_MAP_ENTRY(nsISHistory)

   273    NS_INTERFACE_MAP_ENTRY(nsIWebNavigation)

   274    NS_INTERFACE_MAP_ENTRY(nsISHistoryInternal)

   275 NS_INTERFACE_MAP_END

   277 //*****************************************************************************

   278 //    nsSHistory: nsISHistory

   279 //*****************************************************************************

   281 // static

   282 uint32_t

   283 nsSHistory::CalcMaxTotalViewers()

   284 {

   285   // Calculate an estimate of how many ContentViewers we should cache based

   286   // on RAM.  This assumes that the average ContentViewer is 4MB (conservative)

   287   // and caps the max at 8 ContentViewers

   288   //

   289   // TODO: Should we split the cache memory betw. ContentViewer caching and

   290   // nsCacheService?

   291   //

   292   // RAM      ContentViewers

   293   // -----------------------

   294   // 32   Mb       0

   295   // 64   Mb       1

   296   // 128  Mb       2

   297   // 256  Mb       3

   298   // 512  Mb       5

   299   // 1024 Mb       8

   300   // 2048 Mb       8

   301   // 4096 Mb       8

   302   uint64_t bytes = PR_GetPhysicalMemorySize();

   304   if (bytes == 0)

   305     return 0;

   307   // Conversion from unsigned int64_t to double doesn't work on all platforms.

   308   // We need to truncate the value at INT64_MAX to make sure we don't

   309   // overflow.

   310   if (bytes > INT64_MAX)

   311     bytes = INT64_MAX;

   313   double kBytesD = (double)(bytes >> 10);

   315   // This is essentially the same calculation as for nsCacheService,

   316   // except that we divide the final memory calculation by 4, since

   317   // we assume each ContentViewer takes on average 4MB

   318   uint32_t viewers = 0;

   319   double x = std::log(kBytesD)/std::log(2.0) - 14;

   320   if (x > 0) {

   321     viewers    = (uint32_t)(x * x - x + 2.001); // add .001 for rounding

   322     viewers   /= 4;

   323   }

   325   // Cap it off at 8 max

   326   if (viewers > 8) {

   327     viewers = 8;

   328   }

   329   return viewers;

   330 }

   332 // static

   333 void

   334 nsSHistory::UpdatePrefs()

   335 {

   336   Preferences::GetInt(PREF_SHISTORY_SIZE, &gHistoryMaxSize);

   337   Preferences::GetInt(PREF_SHISTORY_MAX_TOTAL_VIEWERS,

   338                       &sHistoryMaxTotalViewers);

   339   // If the pref is negative, that means we calculate how many viewers

   340   // we think we should cache, based on total memory

   341   if (sHistoryMaxTotalViewers < 0) {

   342     sHistoryMaxTotalViewers = CalcMaxTotalViewers();

   343   }

   344 }

   346 // static

   347 nsresult

   348 nsSHistory::Startup()

   349 {

   350   UpdatePrefs();

   352   // The goal of this is to unbreak users who have inadvertently set their

   353   // session history size to less than the default value.

   354   int32_t defaultHistoryMaxSize =

   355     Preferences::GetDefaultInt(PREF_SHISTORY_SIZE, 50);

   356   if (gHistoryMaxSize < defaultHistoryMaxSize) {

   357     gHistoryMaxSize = defaultHistoryMaxSize;

   358   }

   360   // Allow the user to override the max total number of cached viewers,

   361   // but keep the per SHistory cached viewer limit constant

   362   if (!gObserver) {

   363     gObserver = new nsSHistoryObserver();

   364     NS_ADDREF(gObserver);

   365     Preferences::AddStrongObservers(gObserver, kObservedPrefs);

   367     nsCOMPtr<nsIObserverService> obsSvc =

   368       mozilla::services::GetObserverService();

   369     if (obsSvc) {

   370       // Observe empty-cache notifications so tahat clearing the disk/memory

   371       // cache will also evict all content viewers.

   372       obsSvc->AddObserver(gObserver,

   373                           NS_CACHESERVICE_EMPTYCACHE_TOPIC_ID, false);

   375       // Same for memory-pressure notifications

   376       obsSvc->AddObserver(gObserver, "memory-pressure", false);

   377     }

   378   }

   380   // Initialize the global list of all SHistory objects

   381   PR_INIT_CLIST(&gSHistoryList);

   382   return NS_OK;

   383 }

   385 // static

   386 void

   387 nsSHistory::Shutdown()

   388 {

   389   if (gObserver) {

   390     Preferences::RemoveObservers(gObserver, kObservedPrefs);

   391     nsCOMPtr<nsIObserverService> obsSvc =

   392       mozilla::services::GetObserverService();

   393     if (obsSvc) {

   394       obsSvc->RemoveObserver(gObserver, NS_CACHESERVICE_EMPTYCACHE_TOPIC_ID);

   395       obsSvc->RemoveObserver(gObserver, "memory-pressure");

   396     }

   397     NS_RELEASE(gObserver);

   398   }

   399 }

   401 /* Add an entry to the History list at mIndex and

   402  * increment the index to point to the new entry

   403  */

   404 NS_IMETHODIMP

   405 nsSHistory::AddEntry(nsISHEntry * aSHEntry, bool aPersist)

   406 {

   407   NS_ENSURE_ARG(aSHEntry);

   409   nsCOMPtr<nsISHTransaction> currentTxn;

   411   if(mListRoot)

   412     GetTransactionAtIndex(mIndex, getter_AddRefs(currentTxn));

   414   bool currentPersist = true;

   415   if(currentTxn)

   416     currentTxn->GetPersist(&currentPersist);

   418   int32_t currentIndex = mIndex;

   420   if(!currentPersist)

   421   {

   422     NOTIFY_LISTENERS(OnHistoryReplaceEntry, (currentIndex));

   423     NS_ENSURE_SUCCESS(currentTxn->SetSHEntry(aSHEntry),NS_ERROR_FAILURE);

   424     currentTxn->SetPersist(aPersist);

   425     return NS_OK;

   426   }

   428   nsCOMPtr<nsISHTransaction> txn(do_CreateInstance(NS_SHTRANSACTION_CONTRACTID));

   429   NS_ENSURE_TRUE(txn, NS_ERROR_FAILURE);

   431   nsCOMPtr<nsIURI> uri;

   432   aSHEntry->GetURI(getter_AddRefs(uri));

   433   NOTIFY_LISTENERS(OnHistoryNewEntry, (uri));

   435   // If a listener has changed mIndex, we need to get currentTxn again,

   436   // otherwise we'll be left at an inconsistent state (see bug 320742)

   437   if (currentIndex != mIndex) {

   438     GetTransactionAtIndex(mIndex, getter_AddRefs(currentTxn));

   439   }

   441   // Set the ShEntry and parent for the transaction. setting the

   442   // parent will properly set the parent child relationship

   443   txn->SetPersist(aPersist);

   444   NS_ENSURE_SUCCESS(txn->Create(aSHEntry, currentTxn), NS_ERROR_FAILURE);

   446   // A little tricky math here...  Basically when adding an object regardless of

   447   // what the length was before, it should always be set back to the current and

   448   // lop off the forward.

   449   mLength = (++mIndex + 1);

   451   // If this is the very first transaction, initialize the list

   452   if(!mListRoot)

   453     mListRoot = txn;

   455   // Purge History list if it is too long

   456   if ((gHistoryMaxSize >= 0) && (mLength > gHistoryMaxSize))

   457     PurgeHistory(mLength-gHistoryMaxSize);

   459   RemoveDynEntries(mIndex - 1, mIndex);

   460   return NS_OK;

   461 }

   463 /* Get size of the history list */

   464 NS_IMETHODIMP

   465 nsSHistory::GetCount(int32_t * aResult)

   466 {

   467   NS_ENSURE_ARG_POINTER(aResult);

   468   *aResult = mLength;

   469   return NS_OK;

   470 }

   472 /* Get index of the history list */

   473 NS_IMETHODIMP

   474 nsSHistory::GetIndex(int32_t * aResult)

   475 {

   476   NS_PRECONDITION(aResult, "null out param?");

   477   *aResult = mIndex;

   478   return NS_OK;

   479 }

   481 /* Get the requestedIndex */

   482 NS_IMETHODIMP

   483 nsSHistory::GetRequestedIndex(int32_t * aResult)

   484 {

   485   NS_PRECONDITION(aResult, "null out param?");

   486   *aResult = mRequestedIndex;

   487   return NS_OK;

   488 }

   490 /* Get the entry at a given index */

   491 NS_IMETHODIMP

   492 nsSHistory::GetEntryAtIndex(int32_t aIndex, bool aModifyIndex, nsISHEntry** aResult)

   493 {

   494   nsresult rv;

   495   nsCOMPtr<nsISHTransaction> txn;

   497   /* GetTransactionAtIndex ensures aResult is valid and validates aIndex */

   498   rv = GetTransactionAtIndex(aIndex, getter_AddRefs(txn));

   499   if (NS_SUCCEEDED(rv) && txn) {

   500     //Get the Entry from the transaction

   501     rv = txn->GetSHEntry(aResult);

   502     if (NS_SUCCEEDED(rv) && (*aResult)) {

   503       // Set mIndex to the requested index, if asked to do so..

   504       if (aModifyIndex) {

   505         mIndex = aIndex;

   506       }

   507     } //entry

   508   }  //Transaction

   509   return rv;

   510 }

   512 /* Get the transaction at a given index */

   513 NS_IMETHODIMP

   514 nsSHistory::GetTransactionAtIndex(int32_t aIndex, nsISHTransaction ** aResult)

   515 {

   516   nsresult rv;

   517   NS_ENSURE_ARG_POINTER(aResult);

   519   if ((mLength <= 0) || (aIndex < 0) || (aIndex >= mLength))

   520     return NS_ERROR_FAILURE;

   522   if (!mListRoot)

   523     return NS_ERROR_FAILURE;

   525   if (aIndex == 0)

   526   {

   527     *aResult = mListRoot;

   528     NS_ADDREF(*aResult);

   529     return NS_OK;

   530   }

   531   int32_t   cnt=0;

   532   nsCOMPtr<nsISHTransaction>  tempPtr;

   534   rv = GetRootTransaction(getter_AddRefs(tempPtr));

   535   if (NS_FAILED(rv) || !tempPtr)

   536     return NS_ERROR_FAILURE;

   538   while(1) {

   539     nsCOMPtr<nsISHTransaction> ptr;

   540     rv = tempPtr->GetNext(getter_AddRefs(ptr));

   541     if (NS_SUCCEEDED(rv) && ptr) {

   542       cnt++;

   543       if (cnt == aIndex) {

   544         *aResult = ptr;

   545         NS_ADDREF(*aResult);

   546         break;

   547       }

   548       else {

   549         tempPtr = ptr;

   550         continue;

   551       }

   552     }  //NS_SUCCEEDED

   553     else

   554       return NS_ERROR_FAILURE;

   555   }  // while

   557   return NS_OK;

   558 }

   561 /* Get the index of a given entry */

   562 NS_IMETHODIMP

   563 nsSHistory::GetIndexOfEntry(nsISHEntry* aSHEntry, int32_t* aResult) {

   564   NS_ENSURE_ARG(aSHEntry);

   565   NS_ENSURE_ARG_POINTER(aResult);

   566   *aResult = -1;

   568   if (mLength <= 0) {

   569     return NS_ERROR_FAILURE;

   570   }

   572   nsCOMPtr<nsISHTransaction> currentTxn;

   573   int32_t cnt = 0;

   575   nsresult rv = GetRootTransaction(getter_AddRefs(currentTxn));

   576   if (NS_FAILED(rv) || !currentTxn) {

   577     return NS_ERROR_FAILURE;

   578   }

   580   while (true) {

   581     nsCOMPtr<nsISHEntry> entry;

   582     rv = currentTxn->GetSHEntry(getter_AddRefs(entry));

   583     if (NS_FAILED(rv) || !entry) {

   584       return NS_ERROR_FAILURE;

   585     }

   587     if (aSHEntry == entry) {

   588       *aResult = cnt;

   589       break;

   590     }

   592     rv = currentTxn->GetNext(getter_AddRefs(currentTxn));

   593     if (NS_FAILED(rv) || !currentTxn) {

   594       return NS_ERROR_FAILURE;

   595     }

   597     cnt++;

   598   }

   600   return NS_OK;

   601 }

   604 #ifdef DEBUG

   605 nsresult

   606 nsSHistory::PrintHistory()

   607 {

   609   nsCOMPtr<nsISHTransaction>   txn;

   610   int32_t index = 0;

   611   nsresult rv;

   613   if (!mListRoot)

   614     return NS_ERROR_FAILURE;

   616   txn = mListRoot;

   618   while (1) {

   619     if (!txn)

   620       break;

   621     nsCOMPtr<nsISHEntry>  entry;

   622     rv = txn->GetSHEntry(getter_AddRefs(entry));

   623     if (NS_FAILED(rv) && !entry)

   624       return NS_ERROR_FAILURE;

   626     nsCOMPtr<nsILayoutHistoryState> layoutHistoryState;

   627     nsCOMPtr<nsIURI>  uri;

   628     nsXPIDLString title;

   630     entry->GetLayoutHistoryState(getter_AddRefs(layoutHistoryState));

   631     entry->GetURI(getter_AddRefs(uri));

   632     entry->GetTitle(getter_Copies(title));

   634 #if 0

   635     nsAutoCString url;

   636     if (uri)

   637      uri->GetSpec(url);

   639     printf("**** SH Transaction #%d, Entry = %x\n", index, entry.get());

   640     printf("\t\t URL = %s\n", url.get());

   642     printf("\t\t Title = %s\n", NS_LossyConvertUTF16toASCII(title).get());

   643     printf("\t\t layout History Data = %x\n", layoutHistoryState.get());

   644 #endif

   646     nsCOMPtr<nsISHTransaction> next;

   647     rv = txn->GetNext(getter_AddRefs(next));

   648     if (NS_SUCCEEDED(rv) && next) {

   649       txn = next;

   650       index++;

   651       continue;

   652     }

   653     else

   654       break;

   655   }

   657   return NS_OK;

   658 }

   659 #endif

   662 NS_IMETHODIMP

   663 nsSHistory::GetRootTransaction(nsISHTransaction ** aResult)

   664 {

   665   NS_ENSURE_ARG_POINTER(aResult);

   666   *aResult=mListRoot;

   667   NS_IF_ADDREF(*aResult);

   668   return NS_OK;

   669 }

   671 /* Get the max size of the history list */

   672 NS_IMETHODIMP

   673 nsSHistory::GetMaxLength(int32_t * aResult)

   674 {

   675   NS_ENSURE_ARG_POINTER(aResult);

   676   *aResult = gHistoryMaxSize;

   677   return NS_OK;

   678 }

   680 /* Set the max size of the history list */

   681 NS_IMETHODIMP

   682 nsSHistory::SetMaxLength(int32_t aMaxSize)

   683 {

   684   if (aMaxSize < 0)

   685     return NS_ERROR_ILLEGAL_VALUE;

   687   gHistoryMaxSize = aMaxSize;

   688   if (mLength > aMaxSize)

   689     PurgeHistory(mLength-aMaxSize);

   690   return NS_OK;

   691 }

   693 NS_IMETHODIMP

   694 nsSHistory::PurgeHistory(int32_t aEntries)

   695 {

   696   if (mLength <= 0 || aEntries <= 0)

   697     return NS_ERROR_FAILURE;

   699   aEntries = std::min(aEntries, mLength);

   701   bool purgeHistory = true;

   702   NOTIFY_LISTENERS_CANCELABLE(OnHistoryPurge, purgeHistory,

   703                               (aEntries, &purgeHistory));

   705   if (!purgeHistory) {

   706     // Listener asked us not to purge

   707     return NS_SUCCESS_LOSS_OF_INSIGNIFICANT_DATA;

   708   }

   710   int32_t cnt = 0;

   711   while (cnt < aEntries) {

   712     nsCOMPtr<nsISHTransaction> nextTxn;

   713     if (mListRoot) {

   714       mListRoot->GetNext(getter_AddRefs(nextTxn));

   715       mListRoot->SetNext(nullptr);

   716     }

   717     mListRoot = nextTxn;

   718     if (mListRoot) {

   719       mListRoot->SetPrev(nullptr);

   720     }

   721     cnt++;

   722   }

   723   mLength -= cnt;

   724   mIndex -= cnt;

   726   // Now if we were not at the end of the history, mIndex could have

   727   // become far too negative.  If so, just set it to -1.

   728   if (mIndex < -1) {

   729     mIndex = -1;

   730   }

   732   if (mRootDocShell)

   733     mRootDocShell->HistoryPurged(cnt);

   735   return NS_OK;

   736 }

   739 NS_IMETHODIMP

   740 nsSHistory::AddSHistoryListener(nsISHistoryListener * aListener)

   741 {

   742   NS_ENSURE_ARG_POINTER(aListener);

   744   // Check if the listener supports Weak Reference. This is a must.

   745   // This listener functionality is used by embedders and we want to

   746   // have the right ownership with who ever listens to SHistory

   747   nsWeakPtr listener = do_GetWeakReference(aListener);

   748   if (!listener) return NS_ERROR_FAILURE;

   750   return mListeners.AppendElementUnlessExists(listener) ?

   751     NS_OK : NS_ERROR_OUT_OF_MEMORY;

   752 }

   755 NS_IMETHODIMP

   756 nsSHistory::RemoveSHistoryListener(nsISHistoryListener * aListener)

   757 {

   758   // Make sure the listener that wants to be removed is the

   759   // one we have in store.

   760   nsWeakPtr listener = do_GetWeakReference(aListener);

   761   mListeners.RemoveElement(listener);

   762   return NS_OK;

   763 }

   766 /* Replace an entry in the History list at a particular index.

   767  * Do not update index or count.

   768  */

   769 NS_IMETHODIMP

   770 nsSHistory::ReplaceEntry(int32_t aIndex, nsISHEntry * aReplaceEntry)

   771 {

   772   NS_ENSURE_ARG(aReplaceEntry);

   773   nsresult rv;

   774   nsCOMPtr<nsISHTransaction> currentTxn;

   776   if (!mListRoot) // Session History is not initialised.

   777     return NS_ERROR_FAILURE;

   779   rv = GetTransactionAtIndex(aIndex, getter_AddRefs(currentTxn));

   781   if(currentTxn)

   782   {

   783     NOTIFY_LISTENERS(OnHistoryReplaceEntry, (aIndex));

   785     // Set the replacement entry in the transaction

   786     rv = currentTxn->SetSHEntry(aReplaceEntry);

   787     rv = currentTxn->SetPersist(true);

   788   }

   789   return rv;

   790 }

   792 NS_IMETHODIMP

   793 nsSHistory::NotifyOnHistoryReload(nsIURI* aReloadURI, uint32_t aReloadFlags,

   794                                   bool* aCanReload)

   795 {

   796   NOTIFY_LISTENERS_CANCELABLE(OnHistoryReload, *aCanReload,

   797                               (aReloadURI, aReloadFlags, aCanReload));

   798   return NS_OK;

   799 }

   801 NS_IMETHODIMP

   802 nsSHistory::EvictOutOfRangeContentViewers(int32_t aIndex)

   803 {

   804   // Check our per SHistory object limit in the currently navigated SHistory

   805   EvictOutOfRangeWindowContentViewers(aIndex);

   806   // Check our total limit across all SHistory objects

   807   GloballyEvictContentViewers();

   808   return NS_OK;

   809 }

   811 NS_IMETHODIMP

   812 nsSHistory::EvictAllContentViewers()

   813 {

   814   // XXXbz we don't actually do a good job of evicting things as we should, so

   815   // we might have viewers quite far from mIndex.  So just evict everything.

   816   nsCOMPtr<nsISHTransaction> trans = mListRoot;

   817   while (trans) {

   818     EvictContentViewerForTransaction(trans);

   820     nsISHTransaction *temp = trans;

   821     temp->GetNext(getter_AddRefs(trans));

   822   }

   824   return NS_OK;

   825 }

   829 //*****************************************************************************

   830 //    nsSHistory: nsIWebNavigation

   831 //*****************************************************************************

   833 NS_IMETHODIMP

   834 nsSHistory::GetCanGoBack(bool * aCanGoBack)

   835 {

   836   NS_ENSURE_ARG_POINTER(aCanGoBack);

   837   *aCanGoBack = false;

   839   int32_t index = -1;

   840   NS_ENSURE_SUCCESS(GetIndex(&index), NS_ERROR_FAILURE);

   841   if(index > 0)

   842      *aCanGoBack = true;

   844   return NS_OK;

   845 }

   847 NS_IMETHODIMP

   848 nsSHistory::GetCanGoForward(bool * aCanGoForward)

   849 {

   850   NS_ENSURE_ARG_POINTER(aCanGoForward);

   851   *aCanGoForward = false;

   853   int32_t index = -1;

   854   int32_t count = -1;

   856   NS_ENSURE_SUCCESS(GetIndex(&index), NS_ERROR_FAILURE);

   857   NS_ENSURE_SUCCESS(GetCount(&count), NS_ERROR_FAILURE);

   859   if((index >= 0) && (index < (count - 1)))

   860     *aCanGoForward = true;

   862   return NS_OK;

   863 }

   865 NS_IMETHODIMP

   866 nsSHistory::GoBack()

   867 {

   868   bool canGoBack = false;

   870   GetCanGoBack(&canGoBack);

   871   if (!canGoBack)  // Can't go back

   872     return NS_ERROR_UNEXPECTED;

   873   return LoadEntry(mIndex-1, nsIDocShellLoadInfo::loadHistory, HIST_CMD_BACK);

   874 }

   877 NS_IMETHODIMP

   878 nsSHistory::GoForward()

   879 {

   880   bool canGoForward = false;

   882   GetCanGoForward(&canGoForward);

   883   if (!canGoForward)  // Can't go forward

   884     return NS_ERROR_UNEXPECTED;

   885   return LoadEntry(mIndex+1, nsIDocShellLoadInfo::loadHistory, HIST_CMD_FORWARD);

   886 }

   888 NS_IMETHODIMP

   889 nsSHistory::Reload(uint32_t aReloadFlags)

   890 {

   891   nsDocShellInfoLoadType loadType;

   892   if (aReloadFlags & nsIWebNavigation::LOAD_FLAGS_BYPASS_PROXY &&

   893       aReloadFlags & nsIWebNavigation::LOAD_FLAGS_BYPASS_CACHE)

   894   {

   895     loadType = nsIDocShellLoadInfo::loadReloadBypassProxyAndCache;

   896   }

   897   else if (aReloadFlags & nsIWebNavigation::LOAD_FLAGS_BYPASS_PROXY)

   898   {

   899     loadType = nsIDocShellLoadInfo::loadReloadBypassProxy;

   900   }

   901   else if (aReloadFlags & nsIWebNavigation::LOAD_FLAGS_BYPASS_CACHE)

   902   {

   903     loadType = nsIDocShellLoadInfo::loadReloadBypassCache;

   904   }

   905   else if (aReloadFlags & nsIWebNavigation::LOAD_FLAGS_CHARSET_CHANGE)

   906   {

   907     loadType = nsIDocShellLoadInfo::loadReloadCharsetChange;

   908   }

   909   else if (aReloadFlags & nsIWebNavigation::LOAD_FLAGS_ALLOW_MIXED_CONTENT)

   910   {

   911     loadType = nsIDocShellLoadInfo::loadReloadMixedContent;

   912   }

   913   else

   914   {

   915     loadType = nsIDocShellLoadInfo::loadReloadNormal;

   916   }

   918   // We are reloading. Send Reload notifications.

   919   // nsDocShellLoadFlagType is not public, where as nsIWebNavigation

   920   // is public. So send the reload notifications with the

   921   // nsIWebNavigation flags.

   922   bool canNavigate = true;

   923   nsCOMPtr<nsIURI> currentURI;

   924   GetCurrentURI(getter_AddRefs(currentURI));

   925   NOTIFY_LISTENERS_CANCELABLE(OnHistoryReload, canNavigate,

   926                               (currentURI, aReloadFlags, &canNavigate));

   927   if (!canNavigate)

   928     return NS_OK;

   930   return LoadEntry(mIndex, loadType, HIST_CMD_RELOAD);

   931 }

   933 NS_IMETHODIMP

   934 nsSHistory::ReloadCurrentEntry()

   935 {

   936   // Notify listeners

   937   bool canNavigate = true;

   938   nsCOMPtr<nsIURI> currentURI;

   939   GetCurrentURI(getter_AddRefs(currentURI));

   940   NOTIFY_LISTENERS_CANCELABLE(OnHistoryGotoIndex, canNavigate,

   941                               (mIndex, currentURI, &canNavigate));

   942   if (!canNavigate)

   943     return NS_OK;

   945   return LoadEntry(mIndex, nsIDocShellLoadInfo::loadHistory, HIST_CMD_RELOAD);

   946 }

   948 void

   949 nsSHistory::EvictOutOfRangeWindowContentViewers(int32_t aIndex)

   950 {

   951   // XXX rename method to EvictContentViewersExceptAroundIndex, or something.

   953   // We need to release all content viewers that are no longer in the range

   954   //

   955   //  aIndex - gHistoryMaxViewers to aIndex + gHistoryMaxViewers

   956   //

   957   // to ensure that this SHistory object isn't responsible for more than

   958   // gHistoryMaxViewers content viewers.  But our job is complicated by the

   959   // fact that two transactions which are related by either hash navigations or

   960   // history.pushState will have the same content viewer.

   961   //

   962   // To illustrate the issue, suppose gHistoryMaxViewers = 3 and we have four

   963   // linked transactions in our history.  Suppose we then add a new content

   964   // viewer and call into this function.  So the history looks like:

   965   //

   966   //   A A A A B

   967   //     +     *

   968   //

   969   // where the letters are content viewers and + and * denote the beginning and

   970   // end of the range aIndex +/- gHistoryMaxViewers.

   971   //

   972   // Although one copy of the content viewer A exists outside the range, we

   973   // don't want to evict A, because it has other copies in range!

   974   //

   975   // We therefore adjust our eviction strategy to read:

   976   //

   977   //   Evict each content viewer outside the range aIndex -/+

   978   //   gHistoryMaxViewers, unless that content viewer also appears within the

   979   //   range.

   980   //

   981   // (Note that it's entirely legal to have two copies of one content viewer

   982   // separated by a different content viewer -- call pushState twice, go back

   983   // once, and refresh -- so we can't rely on identical viewers only appearing

   984   // adjacent to one another.)

   986   if (aIndex < 0) {

   987     return;

   988   }

   989   NS_ENSURE_TRUE_VOID(aIndex < mLength);

   991   // Calculate the range that's safe from eviction.

   992   int32_t startSafeIndex = std::max(0, aIndex - gHistoryMaxViewers);

   993   int32_t endSafeIndex = std::min(mLength, aIndex + gHistoryMaxViewers);

   995   LOG(("EvictOutOfRangeWindowContentViewers(index=%d), "

   996        "mLength=%d. Safe range [%d, %d]",

   997        aIndex, mLength, startSafeIndex, endSafeIndex));

   999   // The content viewers in range aIndex -/+ gHistoryMaxViewers will not be

  1000   // evicted.  Collect a set of them so we don't accidentally evict one of them

  1001   // if it appears outside this range.

  1002   nsCOMArray<nsIContentViewer> safeViewers;

  1003   nsCOMPtr<nsISHTransaction> trans;

  1004   GetTransactionAtIndex(startSafeIndex, getter_AddRefs(trans));

  1005   for (int32_t i = startSafeIndex; trans && i <= endSafeIndex; i++) {

  1006     nsCOMPtr<nsIContentViewer> viewer = GetContentViewerForTransaction(trans);

  1007     safeViewers.AppendObject(viewer);

  1008     nsISHTransaction *temp = trans;

  1009     temp->GetNext(getter_AddRefs(trans));

  1010   }

  1012   // Walk the SHistory list and evict any content viewers that aren't safe.

  1013   GetTransactionAtIndex(0, getter_AddRefs(trans));

  1014   while (trans) {

  1015     nsCOMPtr<nsIContentViewer> viewer = GetContentViewerForTransaction(trans);

  1016     if (safeViewers.IndexOf(viewer) == -1) {

  1017       EvictContentViewerForTransaction(trans);

  1018     }

  1020     nsISHTransaction *temp = trans;

  1021     temp->GetNext(getter_AddRefs(trans));

  1022   }

  1023 }

  1025 namespace {

  1027 class TransactionAndDistance

  1028 {

  1029 public:

  1030   TransactionAndDistance(nsISHTransaction *aTrans, uint32_t aDist)

  1031     : mTransaction(aTrans)

  1032     , mDistance(aDist)

  1033   {

  1034     mViewer = GetContentViewerForTransaction(aTrans);

  1035     NS_ASSERTION(mViewer, "Transaction should have a content viewer");

  1037     nsCOMPtr<nsISHEntry> shentry;

  1038     mTransaction->GetSHEntry(getter_AddRefs(shentry));

  1040     nsCOMPtr<nsISHEntryInternal> shentryInternal = do_QueryInterface(shentry);

  1041     if (shentryInternal) {

  1042       shentryInternal->GetLastTouched(&mLastTouched);

  1043     } else {

  1044       NS_WARNING("Can't cast to nsISHEntryInternal?");

  1045       mLastTouched = 0;

  1046     }

  1047   }

  1049   bool operator<(const TransactionAndDistance &aOther) const

  1050   {

  1051     // Compare distances first, and fall back to last-accessed times.

  1052     if (aOther.mDistance != this->mDistance) {

  1053       return this->mDistance < aOther.mDistance;

  1054     }

  1056     return this->mLastTouched < aOther.mLastTouched;

  1057   }

  1059   bool operator==(const TransactionAndDistance &aOther) const

  1060   {

  1061     // This is a little silly; we need == so the default comaprator can be

  1062     // instantiated, but this function is never actually called when we sort

  1063     // the list of TransactionAndDistance objects.

  1064     return aOther.mDistance == this->mDistance &&

  1065            aOther.mLastTouched == this->mLastTouched;

  1066   }

  1068   nsCOMPtr<nsISHTransaction> mTransaction;

  1069   nsCOMPtr<nsIContentViewer> mViewer;

  1070   uint32_t mLastTouched;

  1071   int32_t mDistance;

  1072 };

  1074 } // anonymous namespace

  1076 //static

  1077 void

  1078 nsSHistory::GloballyEvictContentViewers()

  1079 {

  1080   // First, collect from each SHistory object the transactions which have a

  1081   // cached content viewer.  Associate with each transaction its distance from

  1082   // its SHistory's current index.

  1084   nsTArray<TransactionAndDistance> transactions;

  1086   nsSHistory *shist = static_cast<nsSHistory*>(PR_LIST_HEAD(&gSHistoryList));

  1087   while (shist != &gSHistoryList) {

  1089     // Maintain a list of the transactions which have viewers and belong to

  1090     // this particular shist object.  We'll add this list to the global list,

  1091     // |transactions|, eventually.

  1092     nsTArray<TransactionAndDistance> shTransactions;

  1094     // Content viewers are likely to exist only within shist->mIndex -/+

  1095     // gHistoryMaxViewers, so only search within that range.

  1096     //

  1097     // A content viewer might exist outside that range due to either:

  1098     //

  1099     //   * history.pushState or hash navigations, in which case a copy of the

  1100     //     content viewer should exist within the range, or

  1101     //

  1102     //   * bugs which cause us not to call nsSHistory::EvictContentViewers()

  1103     //     often enough.  Once we do call EvictContentViewers() for the

  1104     //     SHistory object in question, we'll do a full search of its history

  1105     //     and evict the out-of-range content viewers, so we don't bother here.

  1106     //

  1107     int32_t startIndex = std::max(0, shist->mIndex - gHistoryMaxViewers);

  1108     int32_t endIndex = std::min(shist->mLength - 1,

  1109                               shist->mIndex + gHistoryMaxViewers);

  1110     nsCOMPtr<nsISHTransaction> trans;

  1111     shist->GetTransactionAtIndex(startIndex, getter_AddRefs(trans));

  1112     for (int32_t i = startIndex; trans && i <= endIndex; i++) {

  1113       nsCOMPtr<nsIContentViewer> contentViewer =

  1114         GetContentViewerForTransaction(trans);

  1116       if (contentViewer) {

  1117         // Because one content viewer might belong to multiple SHEntries, we

  1118         // have to search through shTransactions to see if we already know

  1119         // about this content viewer.  If we find the viewer, update its

  1120         // distance from the SHistory's index and continue.

  1121         bool found = false;

  1122         for (uint32_t j = 0; j < shTransactions.Length(); j++) {

  1123           TransactionAndDistance &container = shTransactions[j];

  1124           if (container.mViewer == contentViewer) {

  1125             container.mDistance = std::min(container.mDistance, DeprecatedAbs(i - shist->mIndex));

  1126             found = true;

  1127             break;

  1128           }

  1129         }

  1131         // If we didn't find a TransactionAndDistance for this content viewer, make a new

  1132         // one.

  1133         if (!found) {

  1134           TransactionAndDistance container(trans, DeprecatedAbs(i - shist->mIndex));

  1135           shTransactions.AppendElement(container);

  1136         }

  1137       }

  1139       nsISHTransaction *temp = trans;

  1140       temp->GetNext(getter_AddRefs(trans));

  1141     }

  1143     // We've found all the transactions belonging to shist which have viewers.

  1144     // Add those transactions to our global list and move on.

  1145     transactions.AppendElements(shTransactions);

  1146     shist = static_cast<nsSHistory*>(PR_NEXT_LINK(shist));

  1147   }

  1149   // We now have collected all cached content viewers.  First check that we

  1150   // have enough that we actually need to evict some.

  1151   if ((int32_t)transactions.Length() <= sHistoryMaxTotalViewers) {

  1152     return;

  1153   }

  1155   // If we need to evict, sort our list of transactions and evict the largest

  1156   // ones.  (We could of course get better algorithmic complexity here by using

  1157   // a heap or something more clever.  But sHistoryMaxTotalViewers isn't large,

  1158   // so let's not worry about it.)

  1159   transactions.Sort();

  1161   for (int32_t i = transactions.Length() - 1;

  1162        i >= sHistoryMaxTotalViewers; --i) {

  1164     EvictContentViewerForTransaction(transactions[i].mTransaction);

  1166   }

  1167 }

  1169 nsresult

  1170 nsSHistory::EvictExpiredContentViewerForEntry(nsIBFCacheEntry *aEntry)

  1171 {

  1172   int32_t startIndex = std::max(0, mIndex - gHistoryMaxViewers);

  1173   int32_t endIndex = std::min(mLength - 1,

  1174                             mIndex + gHistoryMaxViewers);

  1175   nsCOMPtr<nsISHTransaction> trans;

  1176   GetTransactionAtIndex(startIndex, getter_AddRefs(trans));

  1178   int32_t i;

  1179   for (i = startIndex; trans && i <= endIndex; ++i) {

  1180     nsCOMPtr<nsISHEntry> entry;

  1181     trans->GetSHEntry(getter_AddRefs(entry));

  1183     // Does entry have the same BFCacheEntry as the argument to this method?

  1184     if (entry->HasBFCacheEntry(aEntry)) {

  1185       break;

  1186     }

  1188     nsISHTransaction *temp = trans;

  1189     temp->GetNext(getter_AddRefs(trans));

  1190   }

  1191   if (i > endIndex)

  1192     return NS_OK;

  1194   if (i == mIndex) {

  1195     NS_WARNING("How did the current SHEntry expire?");

  1196     return NS_OK;

  1197   }

  1199   EvictContentViewerForTransaction(trans);

  1201   return NS_OK;

  1202 }

  1204 // Evicts all content viewers in all history objects.  This is very

  1205 // inefficient, because it requires a linear search through all SHistory

  1206 // objects for each viewer to be evicted.  However, this method is called

  1207 // infrequently -- only when the disk or memory cache is cleared.

  1209 //static

  1210 void

  1211 nsSHistory::GloballyEvictAllContentViewers()

  1212 {

  1213   int32_t maxViewers = sHistoryMaxTotalViewers;

  1214   sHistoryMaxTotalViewers = 0;

  1215   GloballyEvictContentViewers();

  1216   sHistoryMaxTotalViewers = maxViewers;

  1217 }

  1219 void GetDynamicChildren(nsISHContainer* aContainer,

  1220                         nsTArray<uint64_t>& aDocshellIDs,

  1221                         bool aOnlyTopLevelDynamic)

  1222 {

  1223   int32_t count = 0;

  1224   aContainer->GetChildCount(&count);

  1225   for (int32_t i = 0; i < count; ++i) {

  1226     nsCOMPtr<nsISHEntry> child;

  1227     aContainer->GetChildAt(i, getter_AddRefs(child));

  1228     if (child) {

  1229       bool dynAdded = false;

  1230       child->IsDynamicallyAdded(&dynAdded);

  1231       if (dynAdded) {

  1232         uint64_t docshellID = 0;

  1233         child->GetDocshellID(&docshellID);

  1234         aDocshellIDs.AppendElement(docshellID);

  1235       }

  1236       if (!dynAdded || !aOnlyTopLevelDynamic) {

  1237         nsCOMPtr<nsISHContainer> childAsContainer = do_QueryInterface(child);

  1238         if (childAsContainer) {

  1239           GetDynamicChildren(childAsContainer, aDocshellIDs,

  1240                              aOnlyTopLevelDynamic);

  1241         }

  1242       }

  1243     }

  1244   }

  1245 }

  1247 bool

  1248 RemoveFromSessionHistoryContainer(nsISHContainer* aContainer,

  1249                                   nsTArray<uint64_t>& aDocshellIDs)

  1250 {

  1251   nsCOMPtr<nsISHEntry> root = do_QueryInterface(aContainer);

  1252   NS_ENSURE_TRUE(root, false);

  1254   bool didRemove = false;

  1255   int32_t childCount = 0;

  1256   aContainer->GetChildCount(&childCount);

  1257   for (int32_t i = childCount - 1; i >= 0; --i) {

  1258     nsCOMPtr<nsISHEntry> child;

  1259     aContainer->GetChildAt(i, getter_AddRefs(child));

  1260     if (child) {

  1261       uint64_t docshelldID = 0;

  1262       child->GetDocshellID(&docshelldID);

  1263       if (aDocshellIDs.Contains(docshelldID)) {

  1264         didRemove = true;

  1265         aContainer->RemoveChild(child);

  1266       } else {

  1267         nsCOMPtr<nsISHContainer> container = do_QueryInterface(child);

  1268         if (container) {

  1269           bool childRemoved =

  1270             RemoveFromSessionHistoryContainer(container, aDocshellIDs);

  1271           if (childRemoved) {

  1272             didRemove = true;

  1273           }

  1274         }

  1275       }

  1276     }

  1277   }

  1278   return didRemove;

  1279 }

  1281 bool RemoveChildEntries(nsISHistory* aHistory, int32_t aIndex,

  1282                           nsTArray<uint64_t>& aEntryIDs)

  1283 {

  1284   nsCOMPtr<nsISHEntry> rootHE;

  1285   aHistory->GetEntryAtIndex(aIndex, false, getter_AddRefs(rootHE));

  1286   nsCOMPtr<nsISHContainer> root = do_QueryInterface(rootHE);

  1287   return root ? RemoveFromSessionHistoryContainer(root, aEntryIDs) : false;

  1288 }

  1290 bool IsSameTree(nsISHEntry* aEntry1, nsISHEntry* aEntry2)

  1291 {

  1292   if (!aEntry1 && !aEntry2) {

  1293     return true;

  1294   }

  1295   if ((!aEntry1 && aEntry2) || (aEntry1 && !aEntry2)) {

  1296     return false;

  1297   }

  1298   uint32_t id1, id2;

  1299   aEntry1->GetID(&id1);

  1300   aEntry2->GetID(&id2);

  1301   if (id1 != id2) {

  1302     return false;

  1303   }

  1305   nsCOMPtr<nsISHContainer> container1 = do_QueryInterface(aEntry1);

  1306   nsCOMPtr<nsISHContainer> container2 = do_QueryInterface(aEntry2);

  1307   int32_t count1, count2;

  1308   container1->GetChildCount(&count1);

  1309   container2->GetChildCount(&count2);

  1310   // We allow null entries in the end of the child list.

  1311   int32_t count = std::max(count1, count2);

  1312   for (int32_t i = 0; i < count; ++i) {

  1313     nsCOMPtr<nsISHEntry> child1, child2;

  1314     container1->GetChildAt(i, getter_AddRefs(child1));

  1315     container2->GetChildAt(i, getter_AddRefs(child2));

  1316     if (!IsSameTree(child1, child2)) {

  1317       return false;

  1318     }

  1319   }

  1321   return true;

  1322 }

  1324 bool

  1325 nsSHistory::RemoveDuplicate(int32_t aIndex, bool aKeepNext)

  1326 {

  1327   NS_ASSERTION(aIndex >= 0, "aIndex must be >= 0!");

  1328   NS_ASSERTION(aIndex != 0 || aKeepNext,

  1329                "If we're removing index 0 we must be keeping the next");

  1330   NS_ASSERTION(aIndex != mIndex, "Shouldn't remove mIndex!");

  1331   int32_t compareIndex = aKeepNext ? aIndex + 1 : aIndex - 1;

  1332   nsCOMPtr<nsISHEntry> root1, root2;

  1333   GetEntryAtIndex(aIndex, false, getter_AddRefs(root1));

  1334   GetEntryAtIndex(compareIndex, false, getter_AddRefs(root2));

  1335   if (IsSameTree(root1, root2)) {

  1336     nsCOMPtr<nsISHTransaction> txToRemove, txToKeep, txNext, txPrev;

  1337     GetTransactionAtIndex(aIndex, getter_AddRefs(txToRemove));

  1338     GetTransactionAtIndex(compareIndex, getter_AddRefs(txToKeep));

  1339     NS_ENSURE_TRUE(txToRemove, false);

  1340     NS_ENSURE_TRUE(txToKeep, false);

  1341     txToRemove->GetNext(getter_AddRefs(txNext));

  1342     txToRemove->GetPrev(getter_AddRefs(txPrev));

  1343     txToRemove->SetNext(nullptr);

  1344     txToRemove->SetPrev(nullptr);

  1345     if (aKeepNext) {

  1346       if (txPrev) {

  1347         txPrev->SetNext(txToKeep);

  1348       } else {

  1349         txToKeep->SetPrev(nullptr);

  1350       }

  1351     } else {

  1352       txToKeep->SetNext(txNext);

  1353     }

  1355     if (aIndex == 0 && aKeepNext) {

  1356       NS_ASSERTION(txToRemove == mListRoot,

  1357                    "Transaction at index 0 should be mListRoot!");

  1358       // We're removing the very first session history transaction!

  1359       mListRoot = txToKeep;

  1360     }

  1361     if (mRootDocShell) {

  1362       static_cast<nsDocShell*>(mRootDocShell)->HistoryTransactionRemoved(aIndex);

  1363     }

  1365     // Adjust our indices to reflect the removed transaction

  1366     if (mIndex > aIndex) {

  1367       mIndex = mIndex - 1;

  1368     }

  1370     // NB: If the transaction we are removing is the transaction currently

  1371     // being navigated to (mRequestedIndex) then we adjust the index

  1372     // only if we're not keeping the next entry (because if we are keeping

  1373     // the next entry (because the current is a duplicate of the next), then

  1374     // that entry slides into the spot that we're currently pointing to.

  1375     // We don't do this adjustment for mIndex because mIndex cannot equal

  1376     // aIndex.

  1378     // NB: We don't need to guard on mRequestedIndex being nonzero here,

  1379     // because either they're strictly greater than aIndex which is at least

  1380     // zero, or they are equal to aIndex in which case aKeepNext must be true

  1381     // if aIndex is zero.

  1382     if (mRequestedIndex > aIndex || (mRequestedIndex == aIndex && !aKeepNext)) {

  1383       mRequestedIndex = mRequestedIndex - 1;

  1384     }

  1385     --mLength;

  1386     return true;

  1387   }

  1388   return false;

  1389 }

  1391 NS_IMETHODIMP_(void)

  1392 nsSHistory::RemoveEntries(nsTArray<uint64_t>& aIDs, int32_t aStartIndex)

  1393 {

  1394   int32_t index = aStartIndex;

  1395   while(index >= 0 && RemoveChildEntries(this, --index, aIDs));

  1396   int32_t minIndex = index;

  1397   index = aStartIndex;

  1398   while(index >= 0 && RemoveChildEntries(this, index++, aIDs));

  1400   // We need to remove duplicate nsSHEntry trees.

  1401   bool didRemove = false;

  1402   while (index > minIndex) {

  1403     if (index != mIndex) {

  1404       didRemove = RemoveDuplicate(index, index < mIndex) || didRemove;

  1405     }

  1406     --index;

  1407   }

  1408   if (didRemove && mRootDocShell) {

  1409     nsRefPtr<nsIRunnable> ev =

  1410       NS_NewRunnableMethod(static_cast<nsDocShell*>(mRootDocShell),

  1411                            &nsDocShell::FireDummyOnLocationChange);

  1412     NS_DispatchToCurrentThread(ev);

  1413   }

  1414 }

  1416 void

  1417 nsSHistory::RemoveDynEntries(int32_t aOldIndex, int32_t aNewIndex)

  1418 {

  1419   // Search for the entries which are in the current index,

  1420   // but not in the new one.

  1421   nsCOMPtr<nsISHEntry> originalSH;

  1422   GetEntryAtIndex(aOldIndex, false, getter_AddRefs(originalSH));

  1423   nsCOMPtr<nsISHContainer> originalContainer = do_QueryInterface(originalSH);

  1424   nsAutoTArray<uint64_t, 16> toBeRemovedEntries;

  1425   if (originalContainer) {

  1426     nsTArray<uint64_t> originalDynDocShellIDs;

  1427     GetDynamicChildren(originalContainer, originalDynDocShellIDs, true);

  1428     if (originalDynDocShellIDs.Length()) {

  1429       nsCOMPtr<nsISHEntry> currentSH;

  1430       GetEntryAtIndex(aNewIndex, false, getter_AddRefs(currentSH));

  1431       nsCOMPtr<nsISHContainer> newContainer = do_QueryInterface(currentSH);

  1432       if (newContainer) {

  1433         nsTArray<uint64_t> newDynDocShellIDs;

  1434         GetDynamicChildren(newContainer, newDynDocShellIDs, false);

  1435         for (uint32_t i = 0; i < originalDynDocShellIDs.Length(); ++i) {

  1436           if (!newDynDocShellIDs.Contains(originalDynDocShellIDs[i])) {

  1437             toBeRemovedEntries.AppendElement(originalDynDocShellIDs[i]);

  1438           }

  1439         }

  1440       }

  1441     }

  1442   }

  1443   if (toBeRemovedEntries.Length()) {

  1444     RemoveEntries(toBeRemovedEntries, aOldIndex);

  1445   }

  1446 }

  1448 NS_IMETHODIMP

  1449 nsSHistory::UpdateIndex()

  1450 {

  1451   // Update the actual index with the right value.

  1452   if (mIndex != mRequestedIndex && mRequestedIndex != -1) {

  1453     RemoveDynEntries(mIndex, mRequestedIndex);

  1454     mIndex = mRequestedIndex;

  1455   }

  1457   mRequestedIndex = -1;

  1458   return NS_OK;

  1459 }

  1461 NS_IMETHODIMP

  1462 nsSHistory::Stop(uint32_t aStopFlags)

  1463 {

  1464   //Not implemented

  1465   return NS_OK;

  1466 }

  1469 NS_IMETHODIMP

  1470 nsSHistory::GetDocument(nsIDOMDocument** aDocument)

  1471 {

  1472   // Not implemented

  1473   return NS_OK;

  1474 }

  1477 NS_IMETHODIMP

  1478 nsSHistory::GetCurrentURI(nsIURI** aResultURI)

  1479 {

  1480   NS_ENSURE_ARG_POINTER(aResultURI);

  1481   nsresult rv;

  1483   nsCOMPtr<nsISHEntry> currentEntry;

  1484   rv = GetEntryAtIndex(mIndex, false, getter_AddRefs(currentEntry));

  1485   if (NS_FAILED(rv) && !currentEntry) return rv;

  1486   rv = currentEntry->GetURI(aResultURI);

  1487   return rv;

  1488 }

  1491 NS_IMETHODIMP

  1492 nsSHistory::GetReferringURI(nsIURI** aURI)

  1493 {

  1494   *aURI = nullptr;

  1495   // Not implemented

  1496   return NS_OK;

  1497 }

  1500 NS_IMETHODIMP

  1501 nsSHistory::SetSessionHistory(nsISHistory* aSessionHistory)

  1502 {

  1503   // Not implemented

  1504   return NS_OK;

  1505 }

  1508 NS_IMETHODIMP

  1509 nsSHistory::GetSessionHistory(nsISHistory** aSessionHistory)

  1510 {

  1511   // Not implemented

  1512   return NS_OK;

  1513 }

  1515 NS_IMETHODIMP

  1516 nsSHistory::LoadURIWithBase(const char16_t* aURI,

  1517                             uint32_t aLoadFlags,

  1518                             nsIURI* aReferringURI,

  1519                             nsIInputStream* aPostStream,

  1520                             nsIInputStream* aExtraHeaderStream,

  1521                             nsIURI* aBaseURI)

  1522 {

  1523   return NS_OK;

  1524 }

  1526 NS_IMETHODIMP

  1527 nsSHistory::LoadURI(const char16_t* aURI,

  1528                     uint32_t aLoadFlags,

  1529                     nsIURI* aReferringURI,

  1530                     nsIInputStream* aPostStream,

  1531                     nsIInputStream* aExtraHeaderStream)

  1532 {

  1533   return NS_OK;

  1534 }

  1536 NS_IMETHODIMP

  1537 nsSHistory::GotoIndex(int32_t aIndex)

  1538 {

  1539   return LoadEntry(aIndex, nsIDocShellLoadInfo::loadHistory, HIST_CMD_GOTOINDEX);

  1540 }

  1542 nsresult

  1543 nsSHistory::LoadNextPossibleEntry(int32_t aNewIndex, long aLoadType, uint32_t aHistCmd)

  1544 {

  1545   mRequestedIndex = -1;

  1546   if (aNewIndex < mIndex) {

  1547     return LoadEntry(aNewIndex - 1, aLoadType, aHistCmd);

  1548   }

  1549   if (aNewIndex > mIndex) {

  1550     return LoadEntry(aNewIndex + 1, aLoadType, aHistCmd);

  1551   }

  1552   return NS_ERROR_FAILURE;

  1553 }

  1555 NS_IMETHODIMP

  1556 nsSHistory::LoadEntry(int32_t aIndex, long aLoadType, uint32_t aHistCmd)

  1557 {

  1558   nsCOMPtr<nsIDocShell> docShell;

  1559   // Keep note of requested history index in mRequestedIndex.

  1560   mRequestedIndex = aIndex;

  1562   nsCOMPtr<nsISHEntry> prevEntry;

  1563   GetEntryAtIndex(mIndex, false, getter_AddRefs(prevEntry));

  1565   nsCOMPtr<nsISHEntry> nextEntry;

  1566   GetEntryAtIndex(mRequestedIndex, false, getter_AddRefs(nextEntry));

  1567   if (!nextEntry || !prevEntry) {

  1568     mRequestedIndex = -1;

  1569     return NS_ERROR_FAILURE;

  1570   }

  1572   // Remember that this entry is getting loaded at this point in the sequence

  1573   nsCOMPtr<nsISHEntryInternal> entryInternal = do_QueryInterface(nextEntry);

  1575   if (entryInternal) {

  1576     entryInternal->SetLastTouched(++gTouchCounter);

  1577   }

  1579   // Send appropriate listener notifications

  1580   bool canNavigate = true;

  1581   // Get the uri for the entry we are about to visit

  1582   nsCOMPtr<nsIURI> nextURI;

  1583   nextEntry->GetURI(getter_AddRefs(nextURI));

  1585   if (aHistCmd == HIST_CMD_BACK) {

  1586     // We are going back one entry. Send GoBack notifications

  1587     NOTIFY_LISTENERS_CANCELABLE(OnHistoryGoBack, canNavigate,

  1588                                 (nextURI, &canNavigate));

  1589   } else if (aHistCmd == HIST_CMD_FORWARD) {

  1590     // We are going forward. Send GoForward notification

  1591     NOTIFY_LISTENERS_CANCELABLE(OnHistoryGoForward, canNavigate,

  1592                                 (nextURI, &canNavigate));

  1593   } else if (aHistCmd == HIST_CMD_GOTOINDEX) {

  1594     // We are going somewhere else. This is not reload either

  1595     NOTIFY_LISTENERS_CANCELABLE(OnHistoryGotoIndex, canNavigate,

  1596                                 (aIndex, nextURI, &canNavigate));

  1597   }

  1599   if (!canNavigate) {

  1600     // If the listener asked us not to proceed with

  1601     // the operation, simply return.

  1602     mRequestedIndex = -1;

  1603     return NS_OK;  // XXX Maybe I can return some other error code?

  1604   }

  1606   nsCOMPtr<nsIURI> nexturi;

  1607   int32_t pCount=0, nCount=0;

  1608   nsCOMPtr<nsISHContainer> prevAsContainer(do_QueryInterface(prevEntry));

  1609   nsCOMPtr<nsISHContainer> nextAsContainer(do_QueryInterface(nextEntry));

  1610   if (prevAsContainer && nextAsContainer) {

  1611     prevAsContainer->GetChildCount(&pCount);

  1612     nextAsContainer->GetChildCount(&nCount);

  1613   }

  1615   nsCOMPtr<nsIDocShellLoadInfo> loadInfo;

  1616   if (mRequestedIndex == mIndex) {

  1617     // Possibly a reload case

  1618     docShell = mRootDocShell;

  1619   }

  1620   else {

  1621     // Going back or forward.

  1622     if ((pCount > 0) && (nCount > 0)) {

  1623       /* THis is a subframe navigation. Go find

  1624        * the docshell in which load should happen

  1625        */

  1626       bool frameFound = false;

  1627       nsresult rv = CompareFrames(prevEntry, nextEntry, mRootDocShell, aLoadType, &frameFound);

  1628       if (!frameFound) {

  1629         // We did not successfully find the subframe in which

  1630         // the new url was to be loaded. Go further in the history.

  1631         return LoadNextPossibleEntry(aIndex, aLoadType, aHistCmd);

  1632       }

  1633       return rv;

  1634     }   // (pCount >0)

  1635     else {

  1636       // Loading top level page.

  1637       uint32_t prevID = 0;

  1638       uint32_t nextID = 0;

  1639       prevEntry->GetID(&prevID);

  1640       nextEntry->GetID(&nextID);

  1641       if (prevID == nextID) {

  1642         // Try harder to find something new to load.

  1643         // This may happen for example if some page removed iframes dynamically.

  1644         return LoadNextPossibleEntry(aIndex, aLoadType, aHistCmd);

  1645       }

  1646       docShell = mRootDocShell;

  1647     }

  1648   }

  1650   if (!docShell) {

  1651     // we did not successfully go to the proper index.

  1652     // return error.

  1653     mRequestedIndex = -1;

  1654     return NS_ERROR_FAILURE;

  1655   }

  1657   // Start the load on the appropriate docshell

  1658   return InitiateLoad(nextEntry, docShell, aLoadType);

  1659 }

  1661 nsresult

  1662 nsSHistory::CompareFrames(nsISHEntry * aPrevEntry, nsISHEntry * aNextEntry, nsIDocShell * aParent, long aLoadType, bool * aIsFrameFound)

  1663 {

  1664   if (!aPrevEntry || !aNextEntry || !aParent)

  1665     return NS_ERROR_FAILURE;

  1667   // We should be comparing only entries which were created for the

  1668   // same docshell. This is here to just prevent anything strange happening.

  1669   // This check could be possibly an assertion.

  1670   uint64_t prevdID, nextdID;

  1671   aPrevEntry->GetDocshellID(&prevdID);

  1672   aNextEntry->GetDocshellID(&nextdID);

  1673   NS_ENSURE_STATE(prevdID == nextdID);

  1675   nsresult result = NS_OK;

  1676   uint32_t prevID, nextID;

  1678   aPrevEntry->GetID(&prevID);

  1679   aNextEntry->GetID(&nextID);

  1681   // Check the IDs to verify if the pages are different.

  1682   if (prevID != nextID) {

  1683     if (aIsFrameFound)

  1684       *aIsFrameFound = true;

  1685     // Set the Subframe flag of the entry to indicate that

  1686     // it is subframe navigation

  1687     aNextEntry->SetIsSubFrame(true);

  1688     InitiateLoad(aNextEntry, aParent, aLoadType);

  1689     return NS_OK;

  1690   }

  1692   /* The root entries are the same, so compare any child frames */

  1693   int32_t pcnt=0, ncnt=0, dsCount=0;

  1694   nsCOMPtr<nsISHContainer>  prevContainer(do_QueryInterface(aPrevEntry));

  1695   nsCOMPtr<nsISHContainer>  nextContainer(do_QueryInterface(aNextEntry));

  1697   if (!aParent)

  1698     return NS_ERROR_FAILURE;

  1699   if (!prevContainer || !nextContainer)

  1700     return NS_ERROR_FAILURE;

  1702   prevContainer->GetChildCount(&pcnt);

  1703   nextContainer->GetChildCount(&ncnt);

  1704   aParent->GetChildCount(&dsCount);

  1706   // Create an array for child docshells.

  1707   nsCOMArray<nsIDocShell> docshells;

  1708   for (int32_t i = 0; i < dsCount; ++i) {

  1709     nsCOMPtr<nsIDocShellTreeItem> treeItem;

  1710     aParent->GetChildAt(i, getter_AddRefs(treeItem));

  1711     nsCOMPtr<nsIDocShell> shell = do_QueryInterface(treeItem);

  1712     if (shell) {

  1713       docshells.AppendObject(shell);

  1714     }

  1715   }

  1717   // Search for something to load next.

  1718   for (int32_t i = 0; i < ncnt; ++i) {

  1719     // First get an entry which may cause a new page to be loaded.

  1720     nsCOMPtr<nsISHEntry> nChild;

  1721     nextContainer->GetChildAt(i, getter_AddRefs(nChild));

  1722     if (!nChild) {

  1723       continue;

  1724     }

  1725     uint64_t docshellID = 0;

  1726     nChild->GetDocshellID(&docshellID);

  1728     // Then find the associated docshell.

  1729     nsIDocShell* dsChild = nullptr;

  1730     int32_t count = docshells.Count();

  1731     for (int32_t j = 0; j < count; ++j) {

  1732       uint64_t shellID = 0;

  1733       nsIDocShell* shell = docshells[j];

  1734       shell->GetHistoryID(&shellID);

  1735       if (shellID == docshellID) {

  1736         dsChild = shell;

  1737         break;

  1738       }

  1739     }

  1740     if (!dsChild) {

  1741       continue;

  1742     }

  1744     // Then look at the previous entries to see if there was

  1745     // an entry for the docshell.

  1746     nsCOMPtr<nsISHEntry> pChild;

  1747     for (int32_t k = 0; k < pcnt; ++k) {

  1748       nsCOMPtr<nsISHEntry> child;

  1749       prevContainer->GetChildAt(k, getter_AddRefs(child));

  1750       if (child) {

  1751         uint64_t dID = 0;

  1752         child->GetDocshellID(&dID);

  1753         if (dID == docshellID) {

  1754           pChild = child;

  1755           break;

  1756         }

  1757       }

  1758     }

  1760     // Finally recursively call this method.

  1761     // This will either load a new page to shell or some subshell or

  1762     // do nothing.

  1763     CompareFrames(pChild, nChild, dsChild, aLoadType, aIsFrameFound);

  1764   }

  1765   return result;

  1766 }

  1769 nsresult

  1770 nsSHistory::InitiateLoad(nsISHEntry * aFrameEntry, nsIDocShell * aFrameDS, long aLoadType)

  1771 {

  1772   NS_ENSURE_STATE(aFrameDS && aFrameEntry);

  1774   nsCOMPtr<nsIDocShellLoadInfo> loadInfo;

  1776   /* Set the loadType in the SHEntry too to  what was passed on.

  1777    * This will be passed on to child subframes later in nsDocShell,

  1778    * so that proper loadType is maintained through out a frameset

  1779    */

  1780   aFrameEntry->SetLoadType(aLoadType);

  1781   aFrameDS->CreateLoadInfo (getter_AddRefs(loadInfo));

  1783   loadInfo->SetLoadType(aLoadType);

  1784   loadInfo->SetSHEntry(aFrameEntry);

  1786   nsCOMPtr<nsIURI> nextURI;

  1787   aFrameEntry->GetURI(getter_AddRefs(nextURI));

  1788   // Time   to initiate a document load

  1789   return aFrameDS->LoadURI(nextURI, loadInfo, nsIWebNavigation::LOAD_FLAGS_NONE, false);

  1791 }

  1795 NS_IMETHODIMP

  1796 nsSHistory::SetRootDocShell(nsIDocShell * aDocShell)

  1797 {

  1798   mRootDocShell = aDocShell;

  1799   return NS_OK;

  1800 }

  1802 NS_IMETHODIMP

  1803 nsSHistory::GetRootDocShell(nsIDocShell ** aDocShell)

  1804 {

  1805   NS_ENSURE_ARG_POINTER(aDocShell);

  1807   *aDocShell = mRootDocShell;

  1808   //Not refcounted. May this method should not be available for public

  1809   // NS_IF_ADDREF(*aDocShell);

  1810   return NS_OK;

  1811 }

  1814 NS_IMETHODIMP

  1815 nsSHistory::GetSHistoryEnumerator(nsISimpleEnumerator** aEnumerator)

  1816 {

  1817   nsresult status = NS_OK;

  1819   NS_ENSURE_ARG_POINTER(aEnumerator);

  1820   nsSHEnumerator * iterator = new nsSHEnumerator(this);

  1821   if (iterator && NS_FAILED(status = CallQueryInterface(iterator, aEnumerator)))

  1822     delete iterator;

  1823   return status;

  1824 }

  1827 //*****************************************************************************

  1828 //***    nsSHEnumerator: Object Management

  1829 //*****************************************************************************

  1831 nsSHEnumerator::nsSHEnumerator(nsSHistory * aSHistory):mIndex(-1)

  1832 {

  1833   mSHistory = aSHistory;

  1834 }

  1836 nsSHEnumerator::~nsSHEnumerator()

  1837 {

  1838   mSHistory = nullptr;

  1839 }

  1841 NS_IMPL_ISUPPORTS(nsSHEnumerator, nsISimpleEnumerator)

  1843 NS_IMETHODIMP

  1844 nsSHEnumerator::HasMoreElements(bool * aReturn)

  1845 {

  1846   int32_t cnt;

  1847   *aReturn = false;

  1848   mSHistory->GetCount(&cnt);

  1849   if (mIndex >= -1 && mIndex < (cnt-1) ) {

  1850     *aReturn = true;

  1851   }

  1852   return NS_OK;

  1853 }

  1856 NS_IMETHODIMP

  1857 nsSHEnumerator::GetNext(nsISupports **aItem)

  1858 {

  1859   NS_ENSURE_ARG_POINTER(aItem);

  1860   int32_t cnt= 0;

  1862   nsresult  result = NS_ERROR_FAILURE;

  1863   mSHistory->GetCount(&cnt);

  1864   if (mIndex < (cnt-1)) {

  1865     mIndex++;

  1866     nsCOMPtr<nsISHEntry> hEntry;

  1867     result = mSHistory->GetEntryAtIndex(mIndex, false, getter_AddRefs(hEntry));

  1868     if (hEntry)

  1869       result = CallQueryInterface(hEntry, aItem);

  1870   }

  1871   return result;

  1872 }

The Tor Browser / file revision

docshell/shistory/src/nsSHistory.cpp@925c144e1f1f

docshell/shistory/src/nsSHistory.cpp