diff options
Diffstat (limited to 'base/observer_list.h')
| -rw-r--r-- | base/observer_list.h | 170 |
1 files changed, 35 insertions, 135 deletions
diff --git a/base/observer_list.h b/base/observer_list.h index 0572ba6500..afe1f46cd6 100644 --- a/base/observer_list.h +++ b/base/observer_list.h @@ -11,7 +11,6 @@ #include <limits> #include <vector> -#include "base/gtest_prod_util.h" #include "base/logging.h" #include "base/macros.h" #include "base/memory/weak_ptr.h" @@ -47,14 +46,11 @@ // } // // void NotifyFoo() { -// for (auto& observer : observer_list_) -// observer.OnFoo(this); +// FOR_EACH_OBSERVER(Observer, observer_list_, OnFoo(this)); // } // // void NotifyBar(int x, int y) { -// for (FooList::iterator i = observer_list.begin(), -// e = observer_list.end(); i != e; ++i) -// i->OnBar(this, x, y); +// FOR_EACH_OBSERVER(Observer, observer_list_, OnBar(this, x, y)); // } // // private: @@ -84,66 +80,20 @@ class ObserverListBase NOTIFY_EXISTING_ONLY }; - // An iterator class that can be used to access the list of observers. - template <class ContainerType> - class Iter { + // An iterator class that can be used to access the list of observers. See + // also the FOR_EACH_OBSERVER macro defined below. + class Iterator { public: - Iter(); - explicit Iter(ContainerType* list); - ~Iter(); - - // A workaround for C2244. MSVC requires fully qualified type name for - // return type on a function definition to match a function declaration. - using ThisType = - typename ObserverListBase<ObserverType>::template Iter<ContainerType>; - - bool operator==(const Iter& other) const; - bool operator!=(const Iter& other) const; - ThisType& operator++(); - ObserverType* operator->() const; - ObserverType& operator*() const; + explicit Iterator(ObserverListBase<ObserverType>* list); + ~Iterator(); + ObserverType* GetNext(); private: - FRIEND_TEST_ALL_PREFIXES(ObserverListTest, BasicStdIterator); - FRIEND_TEST_ALL_PREFIXES(ObserverListTest, StdIteratorRemoveFront); - - ObserverType* GetCurrent() const; - void EnsureValidIndex(); - - size_t clamped_max_index() const { - return std::min(max_index_, list_->observers_.size()); - } - - bool is_end() const { return !list_ || index_ == clamped_max_index(); } - WeakPtr<ObserverListBase<ObserverType>> list_; - // When initially constructed and each time the iterator is incremented, - // |index_| is guaranteed to point to a non-null index if the iterator - // has not reached the end of the ObserverList. size_t index_; size_t max_index_; }; - using Iterator = Iter<ObserverListBase<ObserverType>>; - - using iterator = Iter<ObserverListBase<ObserverType>>; - iterator begin() { - // An optimization: do not involve weak pointers for empty list. - // Note: can't use ?: operator here due to some MSVC bug (unit tests fail) - if (observers_.empty()) - return iterator(); - return iterator(this); - } - iterator end() { return iterator(); } - - using const_iterator = Iter<const ObserverListBase<ObserverType>>; - const_iterator begin() const { - if (observers_.empty()) - return const_iterator(); - return const_iterator(this); - } - const_iterator end() const { return const_iterator(); } - ObserverListBase() : notify_depth_(0), type_(NOTIFY_ALL) {} explicit ObserverListBase(NotificationType type) : notify_depth_(0), type_(type) {} @@ -174,99 +124,37 @@ class ObserverListBase int notify_depth_; NotificationType type_; - template <class ContainerType> - friend class Iter; + friend class ObserverListBase::Iterator; DISALLOW_COPY_AND_ASSIGN(ObserverListBase); }; template <class ObserverType> -template <class ContainerType> -ObserverListBase<ObserverType>::Iter<ContainerType>::Iter() - : index_(0), max_index_(0) {} - -template <class ObserverType> -template <class ContainerType> -ObserverListBase<ObserverType>::Iter<ContainerType>::Iter(ContainerType* list) - : list_(const_cast<ObserverListBase<ObserverType>*>(list)->AsWeakPtr()), +ObserverListBase<ObserverType>::Iterator::Iterator( + ObserverListBase<ObserverType>* list) + : list_(list->AsWeakPtr()), index_(0), max_index_(list->type_ == NOTIFY_ALL ? std::numeric_limits<size_t>::max() : list->observers_.size()) { - EnsureValidIndex(); - DCHECK(list_); ++list_->notify_depth_; } template <class ObserverType> -template <class ContainerType> -ObserverListBase<ObserverType>::Iter<ContainerType>::~Iter() { - if (list_ && --list_->notify_depth_ == 0) +ObserverListBase<ObserverType>::Iterator::~Iterator() { + if (list_.get() && --list_->notify_depth_ == 0) list_->Compact(); } template <class ObserverType> -template <class ContainerType> -bool ObserverListBase<ObserverType>::Iter<ContainerType>::operator==( - const Iter& other) const { - if (is_end() && other.is_end()) - return true; - return list_.get() == other.list_.get() && index_ == other.index_; -} - -template <class ObserverType> -template <class ContainerType> -bool ObserverListBase<ObserverType>::Iter<ContainerType>::operator!=( - const Iter& other) const { - return !operator==(other); -} - -template <class ObserverType> -template <class ContainerType> -typename ObserverListBase<ObserverType>::template Iter<ContainerType>& - ObserverListBase<ObserverType>::Iter<ContainerType>::operator++() { - if (list_) { - ++index_; - EnsureValidIndex(); - } - return *this; -} - -template <class ObserverType> -template <class ContainerType> -ObserverType* ObserverListBase<ObserverType>::Iter<ContainerType>::operator->() - const { - ObserverType* current = GetCurrent(); - DCHECK(current); - return current; -} - -template <class ObserverType> -template <class ContainerType> -ObserverType& ObserverListBase<ObserverType>::Iter<ContainerType>::operator*() - const { - ObserverType* current = GetCurrent(); - DCHECK(current); - return *current; -} - -template <class ObserverType> -template <class ContainerType> -ObserverType* ObserverListBase<ObserverType>::Iter<ContainerType>::GetCurrent() - const { - if (!list_) +ObserverType* ObserverListBase<ObserverType>::Iterator::GetNext() { + if (!list_.get()) return nullptr; - return index_ < clamped_max_index() ? list_->observers_[index_] : nullptr; -} - -template <class ObserverType> -template <class ContainerType> -void ObserverListBase<ObserverType>::Iter<ContainerType>::EnsureValidIndex() { - if (!list_) - return; - - size_t max_index = clamped_max_index(); - while (index_ < max_index && !list_->observers_[index_]) + 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_++] : nullptr; } template <class ObserverType> @@ -317,8 +205,9 @@ void ObserverListBase<ObserverType>::Clear() { template <class ObserverType> void ObserverListBase<ObserverType>::Compact() { - observers_.erase(std::remove(observers_.begin(), observers_.end(), nullptr), - observers_.end()); + observers_.erase( + std::remove(observers_.begin(), observers_.end(), nullptr), + observers_.end()); } template <class ObserverType, bool check_empty = false> @@ -344,6 +233,17 @@ class ObserverList : public ObserverListBase<ObserverType> { } }; +#define FOR_EACH_OBSERVER(ObserverType, observer_list, func) \ + do { \ + if ((observer_list).might_have_observers()) { \ + typename base::ObserverListBase<ObserverType>::Iterator \ + it_inside_observer_macro(&observer_list); \ + ObserverType* obs; \ + while ((obs = it_inside_observer_macro.GetNext()) != nullptr) \ + obs->func; \ + } \ + } while (0) + } // namespace base #endif // BASE_OBSERVER_LIST_H_ |