The Tor Browser: comparison ipc/chromium/src/base/observer

--1:000000000000
+:0b388bb55a36
+// Copyright (c) 2006-2008 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.
+#ifndef BASE_OBSERVER_LIST_H__
+#define BASE_OBSERVER_LIST_H__
+#include <algorithm>
+#include <limits>
+#include <vector>
+#include "base/basictypes.h"
+#include "base/logging.h"
+#if defined(ANDROID) && defined(_STLP_STD_NAME)
+using _STLP_STD_NAME::find;
+#endif
+namespace base {
+///////////////////////////////////////////////////////////////////////////////
+//
+// OVERVIEW:
+//
+//   A container for a list of observers.  Unlike a normal STL vector or list,
+//   this container can be modified during iteration without invalidating the
+//   iterator.  So, it safely handles the case of an observer removing itself
+//   or other observers from the list while observers are being notified.
+//
+// TYPICAL USAGE:
+//
+//   class MyWidget {
+//    public:
+//     ...
+//
+//     class Observer {
+//      public:
+//       virtual void OnFoo(MyWidget* w) = 0;
+//       virtual void OnBar(MyWidget* w, int x, int y) = 0;
+//     };
+//
+//     void AddObserver(Observer* obs) {
+//       observer_list_.AddObserver(obs);
+//     }
+//
+//     void RemoveObserver(Observer* obs) {
+//       observer_list_.RemoveObserver(obs);
+//     }
+//
+//     void NotifyFoo() {
+//       FOR_EACH_OBSERVER(Observer, observer_list_, OnFoo(this));
+//     }
+//
+//     void NotifyBar(int x, int y) {
+//       FOR_EACH_OBSERVER(Observer, observer_list_, OnBar(this, x, y));
+//     }
+//
+//    private:
+//     ObserverList<Observer> observer_list_;
+//   };
+//
+//
+///////////////////////////////////////////////////////////////////////////////
+template <class ObserverType, bool check_empty = false>
+class ObserverList {
+public:
+// Enumeration of which observers are notified.
+enum NotificationType {
+// Specifies that any observers added during notification are notified.
+// This is the default type if non type is provided to the constructor.
+NOTIFY_ALL,
+// Specifies that observers added while sending out notification are not
+// notified.
+NOTIFY_EXISTING_ONLY
+};
+ObserverList() : notify_depth_(0), type_(NOTIFY_ALL) {}
+ObserverList(NotificationType type) : notify_depth_(0), type_(type) {}
+~ObserverList() {
+// When check_empty is true, assert that the list is empty on destruction.
+if (check_empty) {
+Compact();
+DCHECK_EQ(observers_.size(), 0U);
+}
+}
+// Add an observer to the list.
+void AddObserver(ObserverType* obs) {
+DCHECK(find(observers_.begin(), observers_.end(), obs) == observers_.end())
+<< "Observers can only be added once!";
+observers_.push_back(obs);
+}
+// Remove an observer from the list.
+void RemoveObserver(ObserverType* obs) {
+typename ListType::iterator it =
+std::find(observers_.begin(), observers_.end(), obs);
+if (it != observers_.end()) {
+if (notify_depth_) {
+*it = 0;
+} else {
+observers_.erase(it);
+}
+}
+}
+size_t size() const {
+return observers_.size();
+}
+ObserverType* GetElementAt(int index) const {
+return observers_[index];
+}
+// An iterator class that can be used to access the list of observers.  See
+// also the FOREACH_OBSERVER macro defined below.
+class Iterator {
+public:
+Iterator(const ObserverList<ObserverType>& list)
+: list_(list),
+index_(0),
+max_index_(list.type_ == NOTIFY_ALL ?
+std::numeric_limits<size_t>::max() :
+list.observers_.size()) {
+++list_.notify_depth_;
+}
+~Iterator() {
+if (--list_.notify_depth_ == 0)
+list_.Compact();
+}
+ObserverType* GetNext() {
+ListType& observers = list_.observers_;
+// Advance if the current element is null
+size_t max_index = std::min(max_index_, observers.size());
+while (index_ < max_index && !observers[index_])
+++index_;
+return index_ < max_index ? observers[index_++] : NULL;
+}
+private:
+const ObserverList<ObserverType>& list_;
+size_t index_;
+size_t max_index_;
+};
+private:
+typedef std::vector<ObserverType*> ListType;
+void Compact() const {
+typename ListType::iterator it = observers_.begin();
+while (it != observers_.end()) {
+if (*it) {
+++it;
+} else {
+it = observers_.erase(it);
+}
+}
+}
+// These are marked mutable to facilitate having NotifyAll be const.
+mutable ListType observers_;
+mutable int notify_depth_;
+NotificationType type_;
+friend class ObserverList::Iterator;
+DISALLOW_EVIL_CONSTRUCTORS(ObserverList);
+};
+} // namespace base
+#define FOR_EACH_OBSERVER(ObserverType, observer_list, func)		\
+do {									\
+base::ObserverList<ObserverType>::Iterator it(observer_list);	\
+ObserverType* obs;							\
+while ((obs = it.GetNext()) != NULL)				\
+obs->func;							\
+} while (0)
+#endif  // BASE_OBSERVER_LIST_H__

The Tor Browser / file comparison

comparison: ipc/chromium/src/base/observer_list.h

ipc/chromium/src/base/observer_list.h