Move declarative API into events API

chrome/renderer/resources/extensions/event.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
   var eventBindingsNatives = requireNative('event_bindings');
   var AttachEvent = eventBindingsNatives.AttachEvent;
   var DetachEvent = eventBindingsNatives.DetachEvent;
+  var sendRequest = require('sendRequest').sendRequest;
+  var utils = require('utils');
 
   var chromeHidden = requireNative('chrome_hidden').GetChromeHidden();
+  var GetExtensionAPIDefinition =
+      requireNative('apiDefinitions').GetExtensionAPIDefinition;
+
+  // Schema definitions for the parameters of functions of Event.
+  var addRulesParams;
+  var getRulesParams;
+  var removeRulesParams;

[not at google - send to devlin, 2012/05/14 07:29:38]

I find this a bit funny to look at out of context. This is specifically for the
rule-based events right? Could you store these in a single object like
"ruleFunctionSchemas" or something with keys "addRules", "getRules", and
"removeRules"?

I find the comment on this quite hard to parse actually, maybe something like

// Schemas for the rule-style functions on the events API that
// only need to be generated occasionally, so populate them lazily.

[battre, 2012/05/15 16:50:09]

Done.

+
+  // This function needs to be called once (only in case Events with rules are
+  // instantiated) to provide the schema definitions for function calls.
+  // |eventsSchema| is the schema of the "events" namespace.
+  function storeFunctionSchemes(eventsSchema) {
+    // Schema definition of Events object.

[not at google - send to devlin, 2012/05/14 07:29:38]

Schemes -> Schemas?

[battre, 2012/05/15 16:50:09]

Done.

+    var eventType = utils.lookup(eventsSchema.types, 'id', 'Event');
+
+    addRulesParams =
+        utils.lookup(eventType.functions, 'name', 'addRules').parameters;
+    getRulesParams =
+        utils.lookup(eventType.functions, 'name', 'getRules').parameters;
+    removeRulesParams =
+        utils.lookup(eventType.functions, 'name', 'removeRules').parameters;
+  }
 
   // Local implementation of JSON.parse & JSON.stringify that protect us
   // from being clobbered by an extension.
   //
   // TODO(aa): This makes me so sad. We shouldn't need it, as we can just pass
   // Values directly over IPC without serializing to strings and use
   // JSONValueConverter.
   chromeHidden.JSON = new (function() {
     var $Object = Object;
     var $Array = Array;
@@ skipping 41 matching lines @@
   // entries "supportsListeners" and "supportsRules".
   chrome.Event = function(opt_eventName, opt_argSchemas, opt_eventOptions) {
     this.eventName_ = opt_eventName;
     this.listeners_ = [];
     this.eventOptions_ = opt_eventOptions ||
         {"supportsListeners": true, "supportsRules": false};
 
     if (this.eventOptions_.supportsRules && !opt_eventName)
       throw new Error("Events that support rules require an event name.");
 
-    // Validate event parameters if we are in debug.
+    // Validate event arguments (the data that is passed to the callbacks)
+    // if we are in debug.
     if (opt_argSchemas &&
         chromeHidden.validateCallbacks &&
         chromeHidden.validate) {
 
-      this.validate_ = function(args) {
+      this.validateEventArgs_ = function(args) {
         try {
           chromeHidden.validate(args, opt_argSchemas);
         } catch (exception) {
           return "Event validation error during " + opt_eventName + " -- " +
                  exception;
         }
       };
     } else {
-      this.validate_ = function() {}
+      this.validateEventArgs_ = function() {}
+    }
+
+    // Initialize schema for functions lazily.
+    if (this.eventOptions_.supportsRules && !addRulesParams) {
+      storeFunctionSchemes(GetExtensionAPIDefinition("events")[0]);

[not at google - send to devlin, 2012/05/14 07:29:38]

You really only need to load these right before calling sendRequest right?  You
could move all of this logic into the storeFunctionSchemes method; call it like
"ensureRuleSchemasLoaded" which early-exists if the ruleFunctionSchemas object
hasn't been populated yet. Then call it right before calling sendRequest each
time.

[battre, 2012/05/15 16:50:09]

Done.

     }
   };
 
   // A map of event names to the event object that is registered to that name.
   var attachedNamedEvents = {};
 
   // An array of all attached event objects, used for detaching on unload.
   var allAttachedEvents = [];
 
   // A map of functions that massage event arguments before they are dispatched.
@@ skipping 89 matching lines @@
 
     return -1;
   };
 
   // Dispatches this event object to all listeners, passing all supplied
   // arguments to this function each listener.
   chrome.Event.prototype.dispatch = function(varargs) {
     if (!this.eventOptions_.supportsListeners)
       throw new Error("This event does not support listeners.");
     var args = Array.prototype.slice.call(arguments);
-    var validationErrors = this.validate_(args);
+    var validationErrors = this.validateEventArgs_(args);
     if (validationErrors) {
       return {validationErrors: validationErrors};
     }
     var results = [];
     for (var i = 0; i < this.listeners_.length; i++) {
       try {
         var result = this.listeners_[i].apply(null, args);
         if (result !== undefined)
           results.push(result);
       } catch (e) {
@@ skipping 33 matching lines @@
     if (!attachedNamedEvents[this.eventName_]) {
       throw new Error("chrome.Event '" + this.eventName_ +
                       "' is not attached.");
     }
 
     delete attachedNamedEvents[this.eventName_];
   };
 
   chrome.Event.prototype.destroy_ = function() {
     this.listeners_ = [];
-    this.validate_ = [];
+    this.validateEventArgs_ = [];
     this.detach_(false);
   };
 
-  // Gets the declarative API object, or undefined if this extension doesn't
-  // have access to it.
-  //
-  // This is defined as a function (rather than a variable) because it isn't
-  // accessible until the schema bindings have been generated.
-  function getDeclarativeAPI() {
-    return chromeHidden.internalAPIs.declarative;
-  }
-
   chrome.Event.prototype.addRules = function(rules, opt_cb) {
     if (!this.eventOptions_.supportsRules)
       throw new Error("This event does not support rules.");
-    if (!getDeclarativeAPI()) {
-      throw new Error("You must have permission to use the declarative " +
-                      "API to support rules in events");
+
+    // Takes a list of JSON datatype identifiers and returns a schema fragment
+    // that verifies that a JSON object corresponds to an array of only these
+    // data types.
+    function buildArrayOfChoicesSchema(typesList) {
+      return {
+        'type': 'array',
+        'items': {
+          'choices': typesList.map(function(el) {return {'$ref': el};})
+        }
+      };
+    };
+
+    // Validate conditions and actions against specific schemas of this
+    // event object type.
+    // |rules| is an array of JSON objects that follow the Rule type of the
+    // declarative extension APIs. |conditions| is an array of JSON type
+    // identifiers that are allowed to occur in the conditions attribute of each
+    // rule. Likewise, |actions| is an array of JSON type identifiers that are
+    // allowed to occur in the actions attribute of each rule.
+    function validateRules(rules, conditions, actions) {
+      var conditionsSchema = buildArrayOfChoicesSchema(conditions);
+      var actionsSchema = buildArrayOfChoicesSchema(actions);
+      rules.forEach(function(rule) {
+        chromeHidden.validate([rule.conditions], [conditionsSchema]);
+        chromeHidden.validate([rule.actions], [actionsSchema]);
+      })
+    };
+
+    if (!this.eventOptions_.conditions || !this.eventOptions_.actions) {
+      throw new Error('Event ' + this.eventName_ + ' misses conditions or ' +
+                'actions in the API specification.');
     }
-    getDeclarativeAPI().addRules(this.eventName_, rules, opt_cb);
+
+    validateRules(rules,
+                  this.eventOptions_.conditions,
+                  this.eventOptions_.actions);
+
+    sendRequest("events.addRules", [this.eventName_, rules, opt_cb],
+                addRulesParams);
   }
 
   chrome.Event.prototype.removeRules = function(ruleIdentifiers, opt_cb) {
     if (!this.eventOptions_.supportsRules)
       throw new Error("This event does not support rules.");
-    if (!getDeclarativeAPI()) {
-      throw new Error("You must have permission to use the declarative " +
-                      "API to support rules in events");
-    }
-    getDeclarativeAPI().removeRules(
-        this.eventName_, ruleIdentifiers, opt_cb);
+    sendRequest("events.removeRules",
+                [this.eventName_, ruleIdentifiers, opt_cb],
+                removeRulesParams);
   }
 
   chrome.Event.prototype.getRules = function(ruleIdentifiers, cb) {
     if (!this.eventOptions_.supportsRules)
       throw new Error("This event does not support rules.");
-    if (!getDeclarativeAPI()) {
-      throw new Error("You must have permission to use the declarative " +
-                      "API to support rules in events");
-    }
-    getDeclarativeAPI().getRules(
-        this.eventName_, ruleIdentifiers, cb);
+    sendRequest("events.getRules",
+                [this.eventName_, ruleIdentifiers, cb],
+                getRulesParams);
   }
 
   // Special load events: we don't use the DOM unload because that slows
   // down tab shutdown.  On the other hand, onUnload might not always fire,
   // since Chrome will terminate renderers on shutdown (SuddenTermination).
   chromeHidden.onLoad = new chrome.Event();
   chromeHidden.onUnload = new chrome.Event();
 
   chromeHidden.dispatchOnLoad =
       chromeHidden.onLoad.dispatch.bind(chromeHidden.onLoad);
 
   chromeHidden.dispatchOnUnload = function() {
     chromeHidden.onUnload.dispatch();
     for (var i = 0; i < allAttachedEvents.length; ++i) {
       var event = allAttachedEvents[i];
       if (event)
         event.detach_(false);
     }
   };
 
   chromeHidden.dispatchError = function(msg) {
     console.error(msg);
   };
 
   exports.Event = chrome.Event;