Bug 548939 - Use SessionStore in tab engine [r=Mardak]

Created a fake SessionStore service for Fennec that imitates the parts of Firefox's SessionStore API that we need. Then used the now "consistent" SessionStore service in the Tabs engine.

services/sync/modules/engines/tabs.js

@@ -104,13 +104,6 @@ TabStore.prototype = {
   __proto__: Store.prototype,
   _remoteClients: {},
 
-  get _sessionStore() {
-    let sessionStore = Cc["@mozilla.org/browser/sessionstore;1"].
-		       getService(Ci.nsISessionStore);
-    this.__defineGetter__("_sessionStore", function() { return sessionStore;});
-    return this._sessionStore;
-  },
-
   itemExists: function TabStore_itemExists(id) {
     return id == Clients.clientID;
   },
@@ -119,33 +112,36 @@ TabStore.prototype = {
   getAllTabs: function getAllTabs(filter) {
     let filteredUrls = new RegExp(Svc.Prefs.get("engine.tabs.filteredUrls"), "i");
 
-    // Iterate through each tab of each window
     let allTabs = [];
-    let wins = Svc.WinMediator.getEnumerator("navigator:browser");
-    while (wins.hasMoreElements()) {
-      // Get the tabs for both Firefox and Fennec
-      let window = wins.getNext();
-      let tabs = window.gBrowser && window.gBrowser.tabContainer.childNodes;
-      tabs = tabs || window.Browser._tabs;
-  
-      // Extract various pieces of tab data
-      Array.forEach(tabs, function(tab) {
-        let browser = tab.linkedBrowser || tab.browser;
-        let url = browser.currentURI.spec;
 
-        // Filter out some urls if necessary
-        if (filter && filteredUrls.test(url))
+    let currentState = JSON.parse(Svc.Session.getBrowserState());
+    currentState.windows.forEach(function(window) {
+      window.tabs.forEach(function(tab) {
+        // Make sure there are history entries to look at.
+        if (!tab.entries.length)
+          return;
+        // Until we store full or partial history, just grab the current entry.
+        // index is 1 based, so make sure we adjust.
+        let entry = tab.entries[tab.index - 1];
+
+        // Filter out some urls if necessary. SessionStore can return empty
+        // tabs in some cases - easiest thing is to just ignore them for now.
+        if (!entry.url || filter && filteredUrls.test(entry.url))
           return;
 
+        // weaveLastUsed will only be set if the tab was ever selected (or
+        // opened after Weave was running). So it might not ever be set.
+        // I think it's also possible that attributes[.image] might not be set
+        // so handle that as well.
         allTabs.push({
-          title: browser.contentTitle || "",
-          urlHistory: [url],
-          icon: browser.mIconURL || "",
-          lastUsed: tab.lastUsed || 0
+          title: entry.title || "",
+          urlHistory: [entry.url],
+          icon: tab.attributes && tab.attributes.image || "",
+          lastUsed: tab.extData && tab.extData.weaveLastUsed || 0
         });
       });
-    }
-  
+    });
+
     return allTabs;
   },
 
@@ -248,7 +244,8 @@ TabTracker.prototype = {
     this._changedIDs[Clients.clientID] = true;
 
     // Store a timestamp in the tab to track when it was last used
-    event.originalTarget.lastUsed = Math.floor(Date.now() / 1000);
+    Svc.Session.setTabValue(event.originalTarget, "weaveLastUsed",
+                            Math.floor(Date.now() / 1000));
   },
 
   get changedIDs() this._changedIDs,

services/sync/modules/util.js

@@ -787,6 +787,57 @@ let FakeSvc = {
   "@mozilla.org/privatebrowsing;1": {
     autoStarted: false,
     privateBrowsingEnabled: false
+  },
+  // Session Restore
+  "@mozilla.org/browser/sessionstore;1": {
+    setTabValue: function(tab, key, value) {
+      if (!tab.__SS_extdata)
+        tab.__SS_extdata = {};
+      tab.__SS_extData[key] = value;
+    },
+    getBrowserState: function() {
+      // Fennec should have only one window. Not more, not less.
+      let state = { windows: [{ tabs: [] }] };
+      let window = Svc.WinMediator.getMostRecentWindow("navigator:browser");
+
+      // Extract various pieces of tab data
+      window.Browser._tabs.forEach(function(tab) {
+        let tabState = { entries: [{}] };
+        let browser = tab.browser;
+
+        // Cases when we want to skip the tab. Could come up if we get
+        // state as a tab is opening or closing.
+        if (!browser || !browser.currentURI || !browser.sessionHistory)
+          return;
+
+        let history = browser.sessionHistory;
+        if (history.count > 0) {
+          // We're only grabbing the current history entry for now.
+          let entry = history.getEntryAtIndex(history.index, false);
+          tabState.entries[0].url = entry.URI.spec;
+          // Like SessionStore really does it...
+          if (entry.title && entry.title != entry.url)
+            tabState.entries[0].title = entry.title;
+        }
+        // index is 1-based
+        tabState.index = 1;
+
+        // Get the image for the tab. Fennec doesn't quite work the same
+        // way as Firefox, so we'll just get this from the browser object.
+        tabState.attributes = { image: browser.mIconURL };
+
+        // Collect the extdata
+        if (tab.__SS_extdata) {
+          tabState.extData = {};
+          for (let key in tab.__SS_extdata)
+            tabState.extData[key] = tab.__SS_extdata[key];
+        }
+
+        // Add the tab to the window
+        state.windows[0].tabs.push(tabState);
+      });
+      return JSON.stringify(state);
+    }
   }
 };
 
@@ -818,6 +869,7 @@ Svc.Obs = Observers;
  ["Version", "@mozilla.org/xpcom/version-comparator;1", "nsIVersionComparator"],
  ["WinMediator", "@mozilla.org/appshell/window-mediator;1", "nsIWindowMediator"],
  ["WinWatcher", "@mozilla.org/embedcomp/window-watcher;1", "nsIWindowWatcher"],
+ ["Session", "@mozilla.org/browser/sessionstore;1", "nsISessionStore"],
 ].forEach(function(lazy) Utils.lazySvc(Svc, lazy[0], lazy[1], Ci[lazy[2]]));
 
 let Str = {};