Bug 636279 - _tabsRestoringCount goes negative if setBrowserState called at browser startup and last session had pinned tab(s); r=zpao

browser/components/sessionstore/src/nsSessionStore.js

@@ -3974,7 +3974,8 @@ SessionStoreService.prototype = {
     this._removeTabsProgressListener(window);
 
     if (previousState == TAB_STATE_RESTORING) {
-      this._tabsRestoringCount--;
+      if (this._tabsRestoringCount)
+        this._tabsRestoringCount--;
     }
     else if (previousState == TAB_STATE_NEEDS_RESTORE) {
       // Make sure the session history listener is removed. This is normally

browser/components/sessionstore/test/browser/Makefile.in

@@ -145,6 +145,7 @@ _BROWSER_TEST_FILES = \
 	browser_625257.js \
 	browser_628270.js \
 	browser_635418.js \
+	browser_636279.js \
 	$(NULL)
 
 ifneq ($(OS_ARCH),Darwin)

browser/components/sessionstore/test/browser/browser_636279.js

@@ -0,0 +1,106 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+let ss = Cc["@mozilla.org/browser/sessionstore;1"].
+         getService(Ci.nsISessionStore);
+
+const TAB_STATE_NEEDS_RESTORE = 1;
+const TAB_STATE_RESTORING = 2;
+
+let stateBackup = ss.getBrowserState();
+
+let statePinned = {windows:[{tabs:[
+  {entries:[{url:"http://example.com#1"}], pinned: true}
+]}]};
+
+let state = {windows:[{tabs:[
+  {entries:[{url:"http://example.com#1"}]},
+  {entries:[{url:"http://example.com#2"}]},
+  {entries:[{url:"http://example.com#3"}]}
+]}]};
+
+function test() {
+  waitForExplicitFinish();
+
+  registerCleanupFunction(function () {
+    Services.prefs.clearUserPref("browser.sessionstore.max_concurrent_tabs");
+    TabsProgressListener.uninit();
+    ss.setBrowserState(stateBackup);
+  });
+
+  Services.prefs.setIntPref("browser.sessionstore.max_concurrent_tabs", 2);
+
+  TabsProgressListener.init();
+
+  window.addEventListener("SSWindowStateReady", function onReady() {
+    window.removeEventListener("SSWindowStateReady", onReady, false);
+
+    let firstProgress = true;
+
+    TabsProgressListener.setCallback(function (needsRestore, isRestoring) {
+      if (firstProgress) {
+        firstProgress = false;
+        is(isRestoring, 2, "restoring 2 tabs concurrently");
+      } else {
+        ok(isRestoring < 3, "restoring max. 2 tabs concurrently");
+      }
+
+      if (0 == needsRestore) {
+        TabsProgressListener.unsetCallback();
+        waitForFocus(finish);
+      }
+    });
+
+    ss.setBrowserState(JSON.stringify(state));
+  }, false);
+
+  ss.setBrowserState(JSON.stringify(statePinned));
+}
+
+function countTabs() {
+  let needsRestore = 0, isRestoring = 0;
+  let windowsEnum = Services.wm.getEnumerator("navigator:browser");
+
+  while (windowsEnum.hasMoreElements()) {
+    let window = windowsEnum.getNext();
+    if (window.closed)
+      continue;
+
+    for (let i = 0; i < window.gBrowser.tabs.length; i++) {
+      let browser = window.gBrowser.tabs[i].linkedBrowser;
+      if (browser.__SS_restoreState == TAB_STATE_RESTORING)
+        isRestoring++;
+      else if (browser.__SS_restoreState == TAB_STATE_NEEDS_RESTORE)
+        needsRestore++;
+    }
+  }
+
+  return [needsRestore, isRestoring];
+}
+
+let TabsProgressListener = {
+  init: function () {
+    gBrowser.addTabsProgressListener(this);
+  },
+
+  uninit: function () {
+    this.unsetCallback();
+    gBrowser.removeTabsProgressListener(this);
+ },
+
+  setCallback: function (callback) {
+    this.callback = callback;
+  },
+
+  unsetCallback: function () {
+    delete this.callback;
+  },
+
+  onStateChange: function (aBrowser, aWebProgress, aRequest, aStateFlags, aStatus) {
+    if (this.callback && aBrowser.__SS_restoreState == TAB_STATE_RESTORING &&
+        aStateFlags & Ci.nsIWebProgressListener.STATE_STOP &&
+        aStateFlags & Ci.nsIWebProgressListener.STATE_IS_NETWORK &&
+        aStateFlags & Ci.nsIWebProgressListener.STATE_IS_WINDOW)
+      this.callback.apply(null, countTabs());
+  }
+}