Implement our own NavigationController

atom/browser/api/lib/navigation-controller.coffee

@@ -0,0 +1,76 @@
+# JavaScript implementation of Chromium's NavigationController.
+# Instead of relying on Chromium for history control, we compeletely do history
+# control on user land, and only rely on WebContents.loadUrl for navigation.
+# This helps us avoid Chromium's various optimizations so we can ensure renderer
+# process is restarted everytime.
+class NavigationController
+  constructor: (@webContents) ->
+    @history = []
+    @currentIndex = -1
+    @pendingIndex = -1
+
+    @webContents.on 'navigation-entry-commited', (event, url) =>
+      if @pendingIndex >= 0  # Go to index.
+        @currentIndex = @pendingIndex
+        @pendingIndex = -1
+        @history[@currentIndex] = url
+      else  # Normal navigation.
+        @history = @history.slice 0, @currentIndex + 1  # Clear history.
+        if @history[@currentIndex] isnt url
+          @currentIndex++
+          @history.push url
+
+  loadUrl: (url, options={}) ->
+    @pendingIndex = -1
+    @webContents._loadUrl url, options
+
+  getUrl: ->
+    if @currentIndex is -1
+      ''
+    else
+      @history[@currentIndex]
+
+  stop: ->
+    @pendingIndex = -1
+    @webContents._stop()
+
+  reload: ->
+    @pendingIndex = @currentIndex
+    @webContents._loadUrl @getUrl(), {}
+
+  reloadIgnoringCache: ->
+    @webContents._reloadIgnoringCache()  # Rely on WebContents to clear cache.
+    @reload()
+
+  canGoBack: ->
+    @currentIndex > 0
+
+  canGoForward: ->
+    @currentIndex < @history.length
+
+  canGoToIndex: (index) ->
+    index >=0 and index < @history.length
+
+  canGoToOffset: (offset) ->
+    @canGoToIndex @currentIndex + offset
+
+  goBack: ->
+    return unless @canGoBack()
+    @pendingIndex = @currentIndex - 1
+    @webContents._loadUrl @history[@pendingIndex], {}
+
+  goForward: ->
+    return unless @canGoForward()
+    @pendingIndex = @currentIndex + 1
+    @webContents._loadUrl @history[@pendingIndex], {}
+
+  goToIndex: (index) ->
+    return unless @canGoToIndex index
+    @pendingIndex = index
+    @webContents._loadUrl @history[@pendingIndex], {}
+
+  goToOffset: (offset) ->
+    return unless @canGoToOffset offset
+    @goToIndex @currentIndex + offset
+
+module.exports = NavigationController