Implementation of AutomationEventQueue and associated framework to support generic non-blocking aut…

chrome/browser/automation/automation_event_queue.cc

+// 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.
+
+#include "chrome/browser/automation/automation_event_observer.h"
+#include "chrome/browser/automation/automation_event_queue.h"
+
+#include "chrome/browser/automation/automation_provider.h"
+#include "chrome/browser/automation/automation_provider_json.h"
+#include "content/public/browser/notification_service.h"
+#include "content/public/browser/notification_types.h"
+
+AutomationEventQueue::AutomationEventQueue()
+    : observer_id_count_(0),
+      wait_reply_message_(NULL),
+      wait_observer_id_(-1) {}
+
+AutomationEventQueue::~AutomationEventQueue() {
+  ClearObservers();
+  Clear();
+}
+
+AutomationEventQueue::AutomationEvent::AutomationEvent(
+    int observer_id, DictionaryValue* event_value)
+    : event_value_(event_value), observer_id_(observer_id) {}
+
+void AutomationEventQueue::AutomationEvent::ReturnValue(
+    AutomationProvider* automation,
+    IPC::Message* reply_message) {
+  AutomationJSONReply(automation, reply_message)
+      .SendSuccess(event_value_.get());
+}
+
+void AutomationEventQueue::GetEvent(AutomationProvider* automation,
+                                    IPC::Message* reply_message,
+                                    int observer_id,
+                                    bool blocking) {
+  SetWait(automation, reply_message, observer_id);
+  bool r = CheckReturnEvent();

[Nirnimesh, 2012/02/24 23:18:09]

use better varnames

[craigdh, 2012/02/27 22:43:38]

Done.

+  if (!r && !blocking) {
+    ClearWait();
+    AutomationJSONReply(automation, reply_message).SendSuccess(NULL);
+  }
+}
+
+void AutomationEventQueue::Clear() {
+  std::list<AutomationEvent*>::iterator i;
+  for (i = event_queue_.begin(); i != event_queue_.end(); i++) {
+    delete *i;
+  }
+  event_queue_.clear();
+}
+
+bool AutomationEventQueue::IsEmpty() {
+  return event_queue_.empty();
+}
+
+AutomationEventQueue::AutomationEvent* AutomationEventQueue::PopEvent() {
+  if (event_queue_.empty()) {
+    return NULL;
+  }
+  AutomationEvent* ret = event_queue_.back();
+  event_queue_.pop_back();
+  return ret;
+}
+
+AutomationEventQueue::AutomationEvent* AutomationEventQueue::PopEvent(
+    int observer_id) {
+  AutomationEvent* ret = NULL;
+  std::list<AutomationEvent*>::reverse_iterator i;
+  for (i = event_queue_.rbegin(); i != event_queue_.rend(); i++) {
+    if (observer_id < 0 || (*i)->GetId() == observer_id) {
+      ret = *i;
+      break;
+    }
+  }
+  if (ret) {
+    event_queue_.remove(ret);
+    return ret;
+  }
+  return NULL;
+}
+
+void AutomationEventQueue::NotifyEvent(
+    AutomationEventQueue::AutomationEvent* event) {
+  event_queue_.push_front(event);
+  CheckReturnEvent();
+}
+
+int AutomationEventQueue::AddObserver(AutomationEventObserver* observer) {
+  int id = observer_id_count_++;
+  observer->Init(id);
+  observers_[id] = observer;
+  return id;
+}
+
+void AutomationEventQueue::RemoveObserver(int observer_id) {
+  if (observers_.count(observer_id)) {
+    delete observers_[observer_id];
+    observers_.erase(observer_id);
+  }
+}
+
+void AutomationEventQueue::ClearObservers() {
+  std::map<int, AutomationEventObserver*>::iterator i;
+  for (i = observers_.begin(); i != observers_.end(); i++) {
+    delete (*i).second;
+  }
+  observers_.clear();
+}
+
+bool AutomationEventQueue::CheckReturnEvent() {
+  if (wait_automation_ && wait_reply_message_.get()) {
+    AutomationEventQueue::AutomationEvent* event = wait_observer_id_ < 0 ?
+                             PopEvent() :
+                             PopEvent(wait_observer_id_);
+    if (event) {
+      event->ReturnValue(wait_automation_, wait_reply_message_.release());
+      delete event;
+      ClearWait();
+      return true;
+    }
+  }
+  return false;
+}
+
+void AutomationEventQueue::SetWait(AutomationProvider* automation,
+                                   IPC::Message* reply_message,
+                                   int observer_id) {
+  wait_automation_ = automation;
+  wait_reply_message_.reset(reply_message);
+  wait_observer_id_ = observer_id;
+}
+
+void AutomationEventQueue::ClearWait() {
+  SetWait(NULL, NULL, -1);
+}