Bug 1097098 : Get tab history calculation offloaded to JS . r=bnicholson

mobile/android/base/Tab.java

@@ -96,7 +96,6 @@ public class Tab {
     public static final int LOAD_PROGRESS_STOP = 100;
 
     private static final int DEFAULT_BACKGROUND_COLOR = Color.WHITE;
-    public static final int MAX_HISTORY_LIST_SIZE = 50;
 
     public enum ErrorType {
         CERT_ERROR,  // Pages with certificate problems

mobile/android/base/tabs/TabHistoryController.java

@@ -34,55 +34,14 @@ public class TabHistoryController {
         this.showTabHistoryListener = showTabHistoryListener;
     }
 
-    public boolean showTabHistory(final Tab tab, final HistoryAction action) {
-        int historyIndex = tab.getHistoryIndex();
-        int historySize = tab.getHistorySize();
-
-        switch(action) {
-        case BACK:
-            if (!tab.canDoBack()) {
-                return false;
-            }
-            return showHistory(Math.max(historyIndex - Tab.MAX_HISTORY_LIST_SIZE, 0), historyIndex, historyIndex);
-
-        case FORWARD:
-            if (!tab.canDoForward()) {
-                return false;
-            }
-            return showHistory(historyIndex, Math.min(historySize - 1, historyIndex + Tab.MAX_HISTORY_LIST_SIZE), historyIndex);
-
-        case ALL:
-            if (!tab.canDoForward() && !tab.canDoBack()) {
-                return false;
-            }
-
-            int min = historyIndex - Tab.MAX_HISTORY_LIST_SIZE / 2;
-            int max = historyIndex + Tab.MAX_HISTORY_LIST_SIZE / 2;
-            if (min < 0) {
-                max -= min;
-            }
-            if (max > historySize - 1) {
-                min -= max - (historySize - 1);
-                max = historySize - 1;
-            }
-            min = Math.max(min, 0);
-
-            return showHistory(min, max, historyIndex);
-
-        default:
-            return false;
-        }
-    }
-
     /**
-     * This method will show the history starting on fromIndex until toIndex of the history.
+     * This method will show the history for the current tab.
      */
-    private boolean showHistory(final int fromIndex, final int toIndex, final int selIndex) {
+    public boolean showTabHistory(final Tab tab, final HistoryAction action) {
         JSONObject json = new JSONObject();
         try {
-            json.put("fromIndex", fromIndex);
-            json.put("toIndex", toIndex);
-            json.put("selIndex", selIndex);
+            json.put("action", action.name());
+            json.put("tabId", tab.getId());
         } catch (JSONException e) {
             Log.e(LOGTAG, "JSON error", e);
         }
@@ -92,17 +51,26 @@ public class TabHistoryController {
             public void onResponse(NativeJSObject nativeJSObject) {
                 /*
                  * The response from gecko request is of the form
-                 * "urls" : [
-                 *            {
-                 *              "title": "google",
-                 *              "url": "google.com",
-                 *              "selected": false
-                 *            }
-                 *          ]
+                 * {
+                 *   "historyItems" : [
+                 *     {
+                 *       "title": "google",
+                 *       "url": "google.com",
+                 *       "selected": false
+                 *     }
+                 *   ],
+                 *   toIndex = 1
+                 * }
                  */
 
                 final NativeJSObject[] historyItems = nativeJSObject.getObjectArray("historyItems");
+                if (historyItems.length == 0) {
+                    // Empty history, return without showing the popup.
+                    return;
+                }
+
                 final List<TabHistoryPage> historyPageList = new ArrayList<>(historyItems.length);
+                final int toIndex = nativeJSObject.getInt("toIndex");
 
                 for (NativeJSObject obj : historyItems) {
                     final String title = obj.getString("title");

mobile/android/chrome/content/browser.js

@@ -293,6 +293,7 @@ Strings.init();
 const kFormHelperModeDisabled = 0;
 const kFormHelperModeEnabled = 1;
 const kFormHelperModeDynamic = 2;   // disabled on tablets
+const kMaxHistoryListSize = 50;
 
 var BrowserApp = {
   _tabs: [],
@@ -1544,6 +1545,17 @@ var BrowserApp = {
 
       case "Session:Navigate":
           let index = JSON.parse(aData);
+          let webNav = BrowserApp.selectedTab.window.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIWebNavigation);
+          let historySize = webNav.sessionHistory.count;
+
+          if (index < 0) {
+            index = 0;
+            Log.e("Browser", "Negative index truncated to zero");
+          } else if (index >= historySize) {
+            Log.e("Browser", "Incorrect index " + index + " truncated to " + historySize - 1);
+            index = historySize - 1;
+          }
+
           browser.gotoIndex(index);
           break;
 
@@ -1961,15 +1973,52 @@ var BrowserApp = {
     this._prefObservers = newPrefObservers;
   },
 
-  // This method will return a list of history items from fromIndex to toIndex, optionally
-  // selecting selIndex(if fromIndex<=selIndex<=toIndex)
+  // This method will return a list of history items and toIndex based on the action provided from the fromIndex to toIndex,
+  // optionally selecting selIndex (if fromIndex <= selIndex <= toIndex)
   getHistory: function(data) {
-    let fromIndex = data.fromIndex;
-    let toIndex = data.toIndex;
-    let selIndex = data.selIndex;
+    let action = data.action;
+    let webNav = BrowserApp.getTabForId(data.tabId).window.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIWebNavigation);
+    let historyIndex = webNav.sessionHistory.index;
+    let historySize = webNav.sessionHistory.count;
+    let canGoBack = webNav.canGoBack;
+    let canGoForward = webNav.canGoForward;
+    let listitems = [];
+    let fromIndex = 0;
+    let toIndex = historySize - 1;
+    let selIndex = historyIndex;
+
+    if (action == "BACK" && canGoBack) {
+      fromIndex = Math.max(historyIndex - kMaxHistoryListSize, 0);
+      toIndex = historyIndex;
+      selIndex = historyIndex;
+    } else if (action == "FORWARD" && canGoForward) {
+      fromIndex = historyIndex;
+      toIndex = Math.min(historySize - 1, historyIndex + kMaxHistoryListSize);
+      selIndex = historyIndex;
+    } else if (action == "ALL" && (canGoBack || canGoForward)){
+      fromIndex = historyIndex - kMaxHistoryListSize / 2;
+      toIndex = historyIndex + kMaxHistoryListSize / 2;
+      if (fromIndex < 0) {
+        toIndex -= fromIndex;
+      }
+
+      if (toIndex > historySize - 1) {
+        fromIndex -= toIndex - (historySize - 1);
+        toIndex = historySize - 1;
+      }
+
+      fromIndex = Math.max(fromIndex, 0);
+      selIndex = historyIndex;
+    } else {
+      // return empty list immediately.
+      return {
+        "historyItems": listitems,
+        "toIndex": toIndex
+      };
+    }
+
     let browser = this.selectedBrowser;
     let hist = browser.sessionHistory;
-    let listitems = [];
     for (let i = toIndex; i >= fromIndex; i--) {
       let entry = hist.getEntryAtIndex(i, false);
       let item = {
@@ -1980,7 +2029,10 @@ var BrowserApp = {
       listitems.push(item);
     }
 
-    return { "historyItems" : listitems };
+    return {
+      "historyItems": listitems,
+      "toIndex": toIndex
+    };
   },
 };