Bug 406160 - user configuration for browser.sessionhistory.max_entries ignored, r=biesi

docshell/shistory/src/nsSHistory.cpp

@@ -56,7 +56,6 @@
 #include "nsIPrefService.h"
 #include "nsIURI.h"
 #include "nsIContentViewer.h"
-#include "nsIPrefBranch2.h"
 #include "nsICacheService.h"
 #include "nsIObserverService.h"
 #include "prclist.h"
@@ -110,13 +109,10 @@ nsSHistoryObserver::Observe(nsISupports *aSubject, const char *aTopic,
 {
   if (!strcmp(aTopic, NS_PREFBRANCH_PREFCHANGE_TOPIC_ID)) {
     nsCOMPtr<nsIPrefBranch> prefs = do_QueryInterface(aSubject);
-    prefs->GetIntPref(PREF_SHISTORY_MAX_TOTAL_VIEWERS,
-                      &nsSHistory::sHistoryMaxTotalViewers);
-    if (nsSHistory::sHistoryMaxTotalViewers < 0) {
-      nsSHistory::sHistoryMaxTotalViewers = nsSHistory::CalcMaxTotalViewers();
+    if (prefs) {
+      nsSHistory::UpdatePrefs(prefs);
+      nsSHistory::EvictGlobalContentViewer();
     }
-
-    nsSHistory::EvictGlobalContentViewer();
   } else if (!strcmp(aTopic, NS_CACHESERVICE_EMPTYCACHE_TOPIC_ID) ||
              !strcmp(aTopic, "memory-pressure")) {
     nsSHistory::EvictAllContentViewersGlobally();
@@ -215,6 +211,20 @@ nsSHistory::CalcMaxTotalViewers()
   return viewers;
 }
 
+// static
+void
+nsSHistory::UpdatePrefs(nsIPrefBranch *aPrefBranch)
+{
+  aPrefBranch->GetIntPref(PREF_SHISTORY_SIZE, &gHistoryMaxSize);
+  aPrefBranch->GetIntPref(PREF_SHISTORY_MAX_TOTAL_VIEWERS,
+                          &sHistoryMaxTotalViewers);
+  // If the pref is negative, that means we calculate how many viewers
+  // we think we should cache, based on total memory
+  if (sHistoryMaxTotalViewers < 0) {
+    sHistoryMaxTotalViewers = CalcMaxTotalViewers();
+  }
+}
+
 // static
 nsresult
 nsSHistory::Startup()
@@ -224,7 +234,7 @@ nsSHistory::Startup()
     nsCOMPtr<nsIPrefBranch> sesHBranch;
     prefs->GetBranch(nsnull, getter_AddRefs(sesHBranch));
     if (sesHBranch) {
-      sesHBranch->GetIntPref(PREF_SHISTORY_SIZE, &gHistoryMaxSize);
+      UpdatePrefs(sesHBranch);
     }
 
     // The goal of this is to unbreak users who have inadvertently set their
@@ -242,14 +252,13 @@ nsSHistory::Startup()
     
     // Allow the user to override the max total number of cached viewers,
     // but keep the per SHistory cached viewer limit constant
-    nsCOMPtr<nsIPrefBranch2> branch = do_QueryInterface(prefs);
+    nsCOMPtr<nsIPrefBranch2> branch = do_QueryInterface(sesHBranch);
     if (branch) {
-      branch->GetIntPref(PREF_SHISTORY_MAX_TOTAL_VIEWERS,
-                         &sHistoryMaxTotalViewers);
       nsSHistoryObserver* obs = new nsSHistoryObserver();
       if (!obs) {
         return NS_ERROR_OUT_OF_MEMORY;
       }
+      branch->AddObserver(PREF_SHISTORY_SIZE, obs, PR_FALSE);
       branch->AddObserver(PREF_SHISTORY_MAX_TOTAL_VIEWERS,
                           obs, PR_FALSE);
 
@@ -266,11 +275,6 @@ nsSHistory::Startup()
       }
     }
   }
-  // If the pref is negative, that means we calculate how many viewers
-  // we think we should cache, based on total memory
-  if (sHistoryMaxTotalViewers < 0) {
-    sHistoryMaxTotalViewers = CalcMaxTotalViewers();
-  }
 
   // Initialize the global list of all SHistory objects
   PR_INIT_CLIST(&gSHistoryList);

docshell/shistory/src/nsSHistory.h

@@ -53,6 +53,7 @@
 #include "nsISHistoryListener.h"
 #include "nsIHistoryEntry.h"
 #include "nsIObserver.h"
+#include "nsIPrefBranch2.h"
 
 // Needed to maintain global list of all SHistory objects
 #include "prclist.h"
@@ -75,6 +76,7 @@ public:
 
   // One time initialization method called upon docshell module construction
   static nsresult Startup();
+  static void UpdatePrefs(nsIPrefBranch *aPrefBranch);
 
   // Max number of total cached content viewers.  If the pref
   // browser.sessionhistory.max_total_viewers is negative, then