Issue 2879 - Move element selection into the content process

lib/child/commands.js

Index: lib/child/commands.js
===================================================================
new file mode 100644
--- /dev/null
+++ b/lib/child/commands.js
@@ -0,0 +1,147 @@
+/*
+ * This Source Code is subject to the terms of the Mozilla Public License
+ * version 2.0 (the "License"). You can obtain a copy of the License at
+ * http://mozilla.org/MPL/2.0/.
+ */
+
+"use strict";
+
+let messageManager = require("messageManager");
+let {getNodeInfo} = require("./nodeInfo");
+let {
+  state, selectElement, setAnchorElement, stopSelection
+} = require("./selection");
+let {getParentElement} = require("./utils");
+
+messageManager.addMessageListener("ElemHideHelper:Command", onCommand);
+
+onShutdown.add(() =>
+{
+  messageManager.removeMessageListener("ElemHideHelper:Command", onCommand);
+});
+
+function onCommand(message)
+{
+  let command = message.data;
+  if (typeof exports[command] == "function")
+    exports[command]();
+}
+
+function quit()
+{
+  stopSelection();
+}
+exports.quit = quit;
+
+function select()
+{
+  if (!state.selectedElement)
+    return;
+
+  messageManager.sendAsyncMessage(
+    "ElemHideHelper:SelectionSucceeded",
+    getNodeInfo(state.selectedElement)
+  );
+  stopSelection();
+}
+exports.select = select;
+
+function wider()
+{
+  if (!state.selectedElement)
+    return;
+
+  let newElement = getParentElement(state.selectedElement);
+  if (!newElement)
+    return;
+
+  state.isUserSelected = true;
+  selectElement(newElement);
+}
+exports.wider = wider;
+
+function narrower()
+{
+  if (!state.selectedElement)
+    return;
+
+  // Search selected element in the parent chain, starting with the ancho
+  // element. We need to select the element just before the selected one.
+  let e = state.anchorElement;
+  let newElement = null;
+  while (e && e != state.selectedElement)
+  {
+    newElement = e;
+    e = getParentElement(e);
+  }
+
+  if (!e || !newElement)
+    return;
+
+  state.isUserSelected = true;
+  selectElement(newElement);
+}
+exports.narrower = narrower;
+
+function lock()
+{
+  if (!state.selectedElement)
+    return;
+
+  if (state.lockedAnchor)
+  {
+    setAnchorElement(state.lockedAnchor);
+    state.lockedAnchor = null;
+  }
+  else
+    state.lockedAnchor = state.anchorElement;
+}
+exports.lock = lock;
+
+let blinkState = null;
+
+function stopBlinking()
+{
+  blinkState.timer.cancel();
+  if (!Cu.isDeadWrapper(blinkState.element))
+    blinkState.element.style.visibility = blinkState.origVisibility;
+  blinkState = null;
+}
+
+function doBlink()
+{
+  if (Cu.isDeadWrapper(blinkState.element))
+  {
+    stopBlinking();
+    return;
+  }
+
+  blinkState.counter++;
+  blinkState.element.style.setProperty(
+    "visibility",
+    (blinkState.counter % 2 == 0 ? "visible" : "hidden"),
+    "important"
+  );
+  if (blinkState.counter == 6)
+    stopBlinking();
+}
+
+function blinkElement()
+{
+  if (!state.selectedElement)
+    return;
+
+  if (blinkState)
+    stopBlinking();
+
+  blinkState = {
+    counter: 0,
+    element: state.selectedElement,
+    origVisibility: state.selectedElement.style.visibility,
+    timer: Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer)
+  };
+
+  blinkState.timer.initWithCallback(doBlink, 250,
+      Ci.nsITimer.TYPE_REPEATING_SLACK);
+}
+exports.blinkElement = blinkElement;