extensions/renderer/resources/automation/automation_custom_bindings.js - chromium/src - Git at Google

 // Copyright 2014 The Chromium Authors
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 // Custom bindings for the automation API.
 const AutomationRootNode = require('automationNode').AutomationRootNode;
 const automationInternal = getInternalApi('automationInternal');
 const exceptionHandler = require('uncaught_exception_handler');
 const logging = requireNative('logging');
 const nativeAutomationInternal = requireNative('automationInternal');
 const DestroyAccessibilityTree =
     nativeAutomationInternal.DestroyAccessibilityTree;
 const StartCachingAccessibilityTrees =
     nativeAutomationInternal.StartCachingAccessibilityTrees;
 const StopCachingAccessibilityTrees =
     nativeAutomationInternal.StopCachingAccessibilityTrees;
 const AddTreeChangeObserver = nativeAutomationInternal.AddTreeChangeObserver;
 const RemoveTreeChangeObserver =
     nativeAutomationInternal.RemoveTreeChangeObserver;
 const GetFocusNative = nativeAutomationInternal.GetFocus;
 const GetAccessibilityFocusNative =
     nativeAutomationInternal.GetAccessibilityFocus;
 const SetDesktopID = nativeAutomationInternal.SetDesktopID;

 // A namespace to export utility functions to other files in automation.
 const automationUtil = function() {};

 // TODO(aboxhall): Look into using WeakMap
 let idToCallback = {};

 let desktopId;
 let desktopTree;

 automationUtil.storeTreeCallback = function(id, callback) {
   if (!callback) {
     return;
   }

   const targetTree = AutomationRootNode.get(id);
   if (!targetTree) {
     // If we haven't cached the tree, hold the callback until the tree is
     // populated by the initial onAccessibilityEvent call.
     if (id in idToCallback) {
       idToCallback[id].push(callback);
     } else {
       idToCallback[id] = [callback];
     }
   } else {
     callback(targetTree);
   }
 };

 /**
  * Global list of tree change observers.
  * @type {Object<number, TreeChangeObserver>}
  */
 automationUtil.treeChangeObserverMap = {};

 /**
  * The id of the next tree change observer.
  * @type {number}
  */
 automationUtil.nextTreeChangeObserverId = 1;

 apiBridge.registerCustomHook(function(bindingsAPI) {
   const apiFunctions = bindingsAPI.apiFunctions;

   apiFunctions.setHandleRequest('getDesktop', function(callback) {
     StartCachingAccessibilityTrees();
     if (desktopId !== undefined) {
       desktopTree = AutomationRootNode.get(desktopId);
     }
     if (!desktopTree) {
       automationInternal.enableDesktop(function(treeId) {
         if (bindingUtil.hasLastError()) {
           AutomationRootNode.destroy(treeId);
           desktopId = undefined;
           SetDesktopID('');
           callback();
           return;
         }
         desktopId = treeId;
         SetDesktopID(desktopId);
         desktopTree = AutomationRootNode.getOrCreate(desktopId);
         callback(desktopTree);

         // TODO(dtseng): Disable desktop tree once desktop object goes out of
         // scope.
       });
     } else {
       callback(desktopTree);
     }
   });

   apiFunctions.setHandleRequest('getFocus', function(callback) {
     const focusedNodeInfo = GetFocusNative();
     if (!focusedNodeInfo) {
       callback(null);
       return;
     }
     const tree = AutomationRootNode.getOrCreate(focusedNodeInfo.treeId);
     if (tree) {
       callback(privates(tree).impl.get(focusedNodeInfo.nodeId));
       return;
     }
   });

   apiFunctions.setHandleRequest('getAccessibilityFocus', function(callback) {
     const focusedNodeInfo = GetAccessibilityFocusNative();
     if (!focusedNodeInfo) {
       callback(null);
       return;
     }
     const tree = AutomationRootNode.getOrCreate(focusedNodeInfo.treeId);
     if (tree) {
       callback(privates(tree).impl.get(focusedNodeInfo.nodeId));
     }
   });

   function removeTreeChangeObserver(observer) {
     for (const id in automationUtil.treeChangeObserverMap) {
       if (automationUtil.treeChangeObserverMap[id] === observer) {
         RemoveTreeChangeObserver(id);
         delete automationUtil.treeChangeObserverMap[id];
         return;
       }
     }
   }
   apiFunctions.setHandleRequest('removeTreeChangeObserver', function(observer) {
     removeTreeChangeObserver(observer);
   });

   function addTreeChangeObserver(filter, observer) {
     removeTreeChangeObserver(observer);
     const id = automationUtil.nextTreeChangeObserverId++;
     AddTreeChangeObserver(id, filter);
     automationUtil.treeChangeObserverMap[id] = observer;
   }
   apiFunctions.setHandleRequest('addTreeChangeObserver',
       function(filter, observer) {
     addTreeChangeObserver(filter, observer);
   });

   apiFunctions.setHandleRequest('setDocumentSelection', function(params) {
     const anchorNodeImpl = privates(params.anchorObject).impl;
     const focusNodeImpl = privates(params.focusObject).impl;
     if (anchorNodeImpl.treeID !== focusNodeImpl.treeID) {
       throw new Error('Selection anchor and focus must be in the same tree.');
     }
     if (anchorNodeImpl.treeID === desktopId) {
       throw new Error('Use AutomationNode.setSelection to set the selection ' +
           'in the desktop tree.');
     }
     automationInternal.performAction(
         {
           treeID: anchorNodeImpl.treeID,
           automationNodeID: anchorNodeImpl.id,
           actionType: 'setSelection',
         },
         {
           focusNodeID: focusNodeImpl.id,
           anchorOffset: params.anchorOffset,
           focusOffset: params.focusOffset,
         });
   });
 });

 automationInternal.onChildTreeID.addListener(function(childTreeId) {
   const targetTree = AutomationRootNode.get(childTreeId);

   // If the tree is already loded, or if we previously requested it be loaded
   // (i.e. have a callback for it), don't try to do so again.
   if (targetTree || idToCallback[childTreeId]) {
     return;
   }

   // A WebView in the desktop tree has a different AX tree as its child.
   // When we encounter a WebView with a child AX tree id that we don't
   // currently have cached, explicitly request that AX tree from the
   // browser process and set up a callback when it loads to attach that
   // tree as a child of this node and fire appropriate events.
   automationUtil.storeTreeCallback(childTreeId, function(root) {
     const rootImpl = privates(root).impl;
     rootImpl.dispatchEvent('loadComplete', 'page');
     if (rootImpl.parent) {
       privates(rootImpl.parent).impl.dispatchEvent('childrenChanged');
     }
   }, true);

   automationInternal.enableTree(childTreeId);
 });

 automationInternal.onTreeChange.addListener(function(
     observerID, treeID, nodeID, changeType) {
   const tree = AutomationRootNode.getOrCreate(treeID);
   if (!tree) {
     return;
   }

   const node = privates(tree).impl.get(nodeID);
   if (!node) {
     return;
   }

   const observer = automationUtil.treeChangeObserverMap[observerID];
   if (!observer) {
     return;
   }

   try {
     observer({target: node, type: changeType});
   } catch (e) {
     exceptionHandler.handle('Error in tree change observer for ' +
         changeType, e);
   }
 });

 automationInternal.onNodesRemoved.addListener(function(treeID, nodeIDs) {
   const tree = AutomationRootNode.getOrCreate(treeID);
   if (!tree) {
     return;
   }

   for (let i = 0; i < nodeIDs.length; i++) {
     privates(tree).impl.remove(nodeIDs[i]);
   }
 });

 automationInternal.onAllAutomationEventListenersRemoved.addListener(() => {
   if (!desktopId) {
     return;
   }
   automationInternal.disableDesktop(() => {
     desktopId = undefined;
     desktopTree = undefined;
     idToCallback = {};
     AutomationRootNode.destroyAll();
     StopCachingAccessibilityTrees();
   });
 });

 /**
  * Dispatch accessibility events fired on individual nodes to its
  * corresponding AutomationNode.
  */
 automationInternal.onAccessibilityEvent.addListener(function(eventParams) {
   const id = eventParams.treeID;
   const targetTree = AutomationRootNode.getOrCreate(id);
   if (eventParams.eventType === 'mediaStartedPlaying' ||
       eventParams.eventType === 'mediaStoppedPlaying') {
     // These events are global to the tree.
     eventParams.targetID = privates(targetTree).impl.id;
   }

   privates(targetTree).impl.onAccessibilityEvent(eventParams);

   // If we're not waiting on a callback, we can early out here.
   if (!(id in idToCallback)) {
     return;
   }

   // We usually get a 'placeholder' tree first, which doesn't have any url
   // attribute or child nodes. If we've got that, wait for the full tree before
   // calling the callback.
   // TODO(dmazzoni): Don't send down placeholder (crbug.com/397553)
   if (id !== desktopId && !targetTree.url && targetTree.children.length === 0) {
     return;
   }

   // If the tree wasn't available, the callback will have been cached in
   // idToCallback, so call and delete it now that we have the complete tree.
   for (let i = 0; i < idToCallback[id].length; i++) {
     const callback = idToCallback[id][i];
     callback(targetTree);
   }
   delete idToCallback[id];
 });

 automationInternal.onAccessibilityTreeDestroyed.addListener(function(id) {
   // Destroy the AutomationRootNode.
   const targetTree = AutomationRootNode.get(id);
   if (targetTree) {
     privates(targetTree).impl.destroy();
     AutomationRootNode.destroy(id);
   } else {
     logging.WARNING('no targetTree to destroy');
   }

   // Destroy the native cache of the accessibility tree.
   DestroyAccessibilityTree(id);
 });

 automationInternal.onAccessibilityTreeSerializationError.addListener(
     function(id) {
   automationInternal.enableTree(id);
 });

 automationInternal.onActionResult.addListener(function(
     treeID, requestID, result) {
   const targetTree = AutomationRootNode.get(treeID);
   if (!targetTree) {
     return;
   }

   privates(targetTree).impl.onActionResult(requestID, result);
 });

 automationInternal.onGetTextLocationResult.addListener(function(
     textLocationParams) {
   const targetTree = AutomationRootNode.get(textLocationParams.treeID);
   if (!targetTree) {
     return;
   }
   privates(targetTree).impl.onGetTextLocationResult(textLocationParams);
 });
	// Copyright 2014 The Chromium Authors
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	// Custom bindings for the automation API.
	const AutomationRootNode = require('automationNode').AutomationRootNode;
	const automationInternal = getInternalApi('automationInternal');
	const exceptionHandler = require('uncaught_exception_handler');
	const logging = requireNative('logging');
	const nativeAutomationInternal = requireNative('automationInternal');
	const DestroyAccessibilityTree =
	nativeAutomationInternal.DestroyAccessibilityTree;
	const StartCachingAccessibilityTrees =
	nativeAutomationInternal.StartCachingAccessibilityTrees;
	const StopCachingAccessibilityTrees =
	nativeAutomationInternal.StopCachingAccessibilityTrees;
	const AddTreeChangeObserver = nativeAutomationInternal.AddTreeChangeObserver;
	const RemoveTreeChangeObserver =
	nativeAutomationInternal.RemoveTreeChangeObserver;
	const GetFocusNative = nativeAutomationInternal.GetFocus;
	const GetAccessibilityFocusNative =
	nativeAutomationInternal.GetAccessibilityFocus;
	const SetDesktopID = nativeAutomationInternal.SetDesktopID;

	// A namespace to export utility functions to other files in automation.
	const automationUtil = function() {};

	// TODO(aboxhall): Look into using WeakMap
	let idToCallback = {};

	let desktopId;
	let desktopTree;

	automationUtil.storeTreeCallback = function(id, callback) {
	if (!callback) {
	return;
	}

	const targetTree = AutomationRootNode.get(id);
	if (!targetTree) {
	// If we haven't cached the tree, hold the callback until the tree is
	// populated by the initial onAccessibilityEvent call.
	if (id in idToCallback) {
	idToCallback[id].push(callback);
	} else {
	idToCallback[id] = [callback];
	}
	} else {
	callback(targetTree);
	}
	};

	/**
	* Global list of tree change observers.
	* @type {Object<number, TreeChangeObserver>}
	*/
	automationUtil.treeChangeObserverMap = {};

	/**
	* The id of the next tree change observer.
	* @type {number}
	*/
	automationUtil.nextTreeChangeObserverId = 1;

	apiBridge.registerCustomHook(function(bindingsAPI) {
	const apiFunctions = bindingsAPI.apiFunctions;

	apiFunctions.setHandleRequest('getDesktop', function(callback) {
	StartCachingAccessibilityTrees();
	if (desktopId !== undefined) {
	desktopTree = AutomationRootNode.get(desktopId);
	}
	if (!desktopTree) {
	automationInternal.enableDesktop(function(treeId) {
	if (bindingUtil.hasLastError()) {
	AutomationRootNode.destroy(treeId);
	desktopId = undefined;
	SetDesktopID('');
	callback();
	return;
	}
	desktopId = treeId;
	SetDesktopID(desktopId);
	desktopTree = AutomationRootNode.getOrCreate(desktopId);
	callback(desktopTree);

	// TODO(dtseng): Disable desktop tree once desktop object goes out of
	// scope.
	});
	} else {
	callback(desktopTree);
	}
	});

	apiFunctions.setHandleRequest('getFocus', function(callback) {
	const focusedNodeInfo = GetFocusNative();
	if (!focusedNodeInfo) {
	callback(null);
	return;
	}
	const tree = AutomationRootNode.getOrCreate(focusedNodeInfo.treeId);
	if (tree) {
	callback(privates(tree).impl.get(focusedNodeInfo.nodeId));
	return;
	}
	});

	apiFunctions.setHandleRequest('getAccessibilityFocus', function(callback) {
	const focusedNodeInfo = GetAccessibilityFocusNative();
	if (!focusedNodeInfo) {
	callback(null);
	return;
	}
	const tree = AutomationRootNode.getOrCreate(focusedNodeInfo.treeId);
	if (tree) {
	callback(privates(tree).impl.get(focusedNodeInfo.nodeId));
	}
	});

	function removeTreeChangeObserver(observer) {
	for (const id in automationUtil.treeChangeObserverMap) {
	if (automationUtil.treeChangeObserverMap[id] === observer) {
	RemoveTreeChangeObserver(id);
	delete automationUtil.treeChangeObserverMap[id];
	return;
	}
	}
	}
	apiFunctions.setHandleRequest('removeTreeChangeObserver', function(observer) {
	removeTreeChangeObserver(observer);
	});

	function addTreeChangeObserver(filter, observer) {
	removeTreeChangeObserver(observer);
	const id = automationUtil.nextTreeChangeObserverId++;
	AddTreeChangeObserver(id, filter);
	automationUtil.treeChangeObserverMap[id] = observer;
	}
	apiFunctions.setHandleRequest('addTreeChangeObserver',
	function(filter, observer) {
	addTreeChangeObserver(filter, observer);
	});

	apiFunctions.setHandleRequest('setDocumentSelection', function(params) {
	const anchorNodeImpl = privates(params.anchorObject).impl;
	const focusNodeImpl = privates(params.focusObject).impl;
	if (anchorNodeImpl.treeID !== focusNodeImpl.treeID) {
	throw new Error('Selection anchor and focus must be in the same tree.');
	}
	if (anchorNodeImpl.treeID === desktopId) {
	throw new Error('Use AutomationNode.setSelection to set the selection ' +
	'in the desktop tree.');
	}
	automationInternal.performAction(
	{
	treeID: anchorNodeImpl.treeID,
	automationNodeID: anchorNodeImpl.id,
	actionType: 'setSelection',
	},
	{
	focusNodeID: focusNodeImpl.id,
	anchorOffset: params.anchorOffset,
	focusOffset: params.focusOffset,
	});
	});
	});

	automationInternal.onChildTreeID.addListener(function(childTreeId) {
	const targetTree = AutomationRootNode.get(childTreeId);

	// If the tree is already loded, or if we previously requested it be loaded
	// (i.e. have a callback for it), don't try to do so again.
	if (targetTree \|\| idToCallback[childTreeId]) {
	return;
	}

	// A WebView in the desktop tree has a different AX tree as its child.
	// When we encounter a WebView with a child AX tree id that we don't
	// currently have cached, explicitly request that AX tree from the
	// browser process and set up a callback when it loads to attach that
	// tree as a child of this node and fire appropriate events.
	automationUtil.storeTreeCallback(childTreeId, function(root) {
	const rootImpl = privates(root).impl;
	rootImpl.dispatchEvent('loadComplete', 'page');
	if (rootImpl.parent) {
	privates(rootImpl.parent).impl.dispatchEvent('childrenChanged');
	}
	}, true);

	automationInternal.enableTree(childTreeId);
	});

	automationInternal.onTreeChange.addListener(function(
	observerID, treeID, nodeID, changeType) {
	const tree = AutomationRootNode.getOrCreate(treeID);
	if (!tree) {
	return;
	}

	const node = privates(tree).impl.get(nodeID);
	if (!node) {
	return;
	}

	const observer = automationUtil.treeChangeObserverMap[observerID];
	if (!observer) {
	return;
	}

	try {
	observer({target: node, type: changeType});
	} catch (e) {
	exceptionHandler.handle('Error in tree change observer for ' +
	changeType, e);
	}
	});

	automationInternal.onNodesRemoved.addListener(function(treeID, nodeIDs) {
	const tree = AutomationRootNode.getOrCreate(treeID);
	if (!tree) {
	return;
	}

	for (let i = 0; i < nodeIDs.length; i++) {
	privates(tree).impl.remove(nodeIDs[i]);
	}
	});

	automationInternal.onAllAutomationEventListenersRemoved.addListener(() => {
	if (!desktopId) {
	return;
	}
	automationInternal.disableDesktop(() => {
	desktopId = undefined;
	desktopTree = undefined;
	idToCallback = {};
	AutomationRootNode.destroyAll();
	StopCachingAccessibilityTrees();
	});
	});

	/**
	* Dispatch accessibility events fired on individual nodes to its
	* corresponding AutomationNode.
	*/
	automationInternal.onAccessibilityEvent.addListener(function(eventParams) {
	const id = eventParams.treeID;
	const targetTree = AutomationRootNode.getOrCreate(id);
	if (eventParams.eventType === 'mediaStartedPlaying' \|\|
	eventParams.eventType === 'mediaStoppedPlaying') {
	// These events are global to the tree.
	eventParams.targetID = privates(targetTree).impl.id;
	}

	privates(targetTree).impl.onAccessibilityEvent(eventParams);

	// If we're not waiting on a callback, we can early out here.
	if (!(id in idToCallback)) {
	return;
	}

	// We usually get a 'placeholder' tree first, which doesn't have any url
	// attribute or child nodes. If we've got that, wait for the full tree before
	// calling the callback.
	// TODO(dmazzoni): Don't send down placeholder (crbug.com/397553)
	if (id !== desktopId && !targetTree.url && targetTree.children.length === 0) {
	return;
	}

	// If the tree wasn't available, the callback will have been cached in
	// idToCallback, so call and delete it now that we have the complete tree.
	for (let i = 0; i < idToCallback[id].length; i++) {
	const callback = idToCallback[id][i];
	callback(targetTree);
	}
	delete idToCallback[id];
	});

	automationInternal.onAccessibilityTreeDestroyed.addListener(function(id) {
	// Destroy the AutomationRootNode.
	const targetTree = AutomationRootNode.get(id);
	if (targetTree) {
	privates(targetTree).impl.destroy();
	AutomationRootNode.destroy(id);
	} else {
	logging.WARNING('no targetTree to destroy');
	}

	// Destroy the native cache of the accessibility tree.
	DestroyAccessibilityTree(id);
	});

	automationInternal.onAccessibilityTreeSerializationError.addListener(
	function(id) {
	automationInternal.enableTree(id);
	});

	automationInternal.onActionResult.addListener(function(
	treeID, requestID, result) {
	const targetTree = AutomationRootNode.get(treeID);
	if (!targetTree) {
	return;
	}

	privates(targetTree).impl.onActionResult(requestID, result);
	});

	automationInternal.onGetTextLocationResult.addListener(function(
	textLocationParams) {
	const targetTree = AutomationRootNode.get(textLocationParams.treeID);
	if (!targetTree) {
	return;
	}
	privates(targetTree).impl.onGetTextLocationResult(textLocationParams);
	});