Bug 701092 - Limit session restore attempts. r=mfinkle

mobile/android/app/mobile.js

@@ -150,6 +150,8 @@ pref("browser.sessionstore.resume_from_crash", true);
 pref("browser.sessionstore.resume_from_crash_timeout", 60); // minutes
 pref("browser.sessionstore.interval", 10000); // milliseconds
 pref("browser.sessionstore.max_tabs_undo", 1);
+pref("browser.sessionstore.max_resumed_crashes", 1);
+pref("browser.sessionstore.recent_crashes", 0);
 
 /* these should help performance */
 pref("mozilla.widget.force-24bpp", true);

mobile/android/chrome/content/browser.js

@@ -269,12 +269,12 @@ var BrowserApp = {
     Cc["@mozilla.org/satchel/form-history;1"].getService(Ci.nsIFormHistory2);
 
     let url = "about:home";
-    let restoreSession = false;
+    let forceRestore = false;
     if ("arguments" in window) {
       if (window.arguments[0])
         url = window.arguments[0];
       if (window.arguments[1])
-        restoreSession = window.arguments[1];
+        forceRestore = window.arguments[1];
       if (window.arguments[2])
         gScreenWidth = window.arguments[2];
       if (window.arguments[3])
@@ -291,7 +291,7 @@ var BrowserApp = {
 
     // restore the previous session
     let ss = Cc["@mozilla.org/browser/sessionstore;1"].getService(Ci.nsISessionStore);
-    if (restoreSession || ss.shouldRestore()) {
+    if (forceRestore || ss.shouldRestore()) {
       // A restored tab should not be active if we are loading a URL
       let restoreToFront = false;
 
@@ -301,20 +301,22 @@ var BrowserApp = {
       } else {
         // Let the session make a restored tab active
         restoreToFront = true;
-
-        // Be ready to handle any restore failures by making sure we have a valid tab opened
-        let restoreCleanup = {
-          observe: function(aSubject, aTopic, aData) {
-            Services.obs.removeObserver(restoreCleanup, "sessionstore-windows-restored");
-            if (aData == "fail")
-              BrowserApp.addTab("about:home");
-          }
-        };
-        Services.obs.addObserver(restoreCleanup, "sessionstore-windows-restored", false);
       }
 
+      // Be ready to handle any restore failures by making sure we have a valid tab opened
+      let restoreCleanup = {
+        observe: function(aSubject, aTopic, aData) {
+          Services.obs.removeObserver(restoreCleanup, "sessionstore-windows-restored");
+          if (aData == "fail") {
+            let params = { selected: restoreToFront };
+            BrowserApp.addTab("about:home");
+          }
+        }
+      };
+      Services.obs.addObserver(restoreCleanup, "sessionstore-windows-restored", false);
+
       // Start the restore
-      ss.restoreLastSession(restoreToFront);
+      ss.restoreLastSession(restoreToFront, forceRestore);
     } else {
       this.addTab(url);
 

mobile/android/components/SessionStore.idl

@@ -111,6 +111,7 @@ interface nsISessionStore : nsISupports
   /**
    * Restores the previous browser session using a fast, lightweight strategy
    * @param aBringToFront should a restored tab be brought to the foreground?
+   * @param aForceRestore  whether we need to force a restore, regardless of the recent crash situation
    */
-  void restoreLastSession(in boolean aBringToFront);
+  void restoreLastSession(in boolean aBringToFront, in boolean aForceRestore);
 };

mobile/android/components/SessionStore.js

@@ -914,16 +914,28 @@ SessionStore.prototype = {
     return this._shouldRestore;
   },
 
-  restoreLastSession: function ss_restoreLastSession(aBringToFront) {
+  restoreLastSession: function ss_restoreLastSession(aBringToFront, aForceRestore) {
     let self = this;
     function notifyObservers(aMessage) {
       self._clearCache();
       Services.obs.notifyObservers(null, "sessionstore-windows-restored", aMessage || "");
     }
 
+    if (!aForceRestore) {
+      let maxCrashes = Services.prefs.getIntPref("browser.sessionstore.max_resumed_crashes");
+      let recentCrashes = Services.prefs.getIntPref("browser.sessionstore.recent_crashes") + 1;
+      Services.prefs.setIntPref("browser.sessionstore.recent_crashes", recentCrashes);
+      Services.prefs.savePrefFile(null);
+
+      if (recentCrashes > maxCrashes) {
+        notifyObservers("fail");
+        return;
+      }
+    }
+
     // The previous session data has already been renamed to the backup file
     if (!this._sessionFileBackup.exists()) {
-      notifyObservers("fail")
+      notifyObservers("fail");
       return;
     }
 

widget/android/nsAppShell.cpp

@@ -386,6 +386,12 @@ nsAppShell::ProcessNextNativeEvent(bool mayWait)
         // of flushing data
         nsIPrefService* prefs = Preferences::GetService();
         if (prefs) {
+            // reset the crash loop state
+            nsCOMPtr<nsIPrefBranch> prefBranch;
+            prefs->GetBranch("browser.sessionstore.", getter_AddRefs(prefBranch));
+            if (prefBranch)
+                prefBranch->SetIntPref("recent_crashes", 0);
+
             prefs->SavePrefFile(nsnull);
         }