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| 1 // Copyright 2013 The Chromium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. |
| 4 |
| 5 #ifndef CONTENT_RENDERER_MEDIA_TAGGED_LIST_H_ |
| 6 #define CONTENT_RENDERER_MEDIA_TAGGED_LIST_H_ |
| 7 |
| 8 #include <algorithm> |
| 9 #include <list> |
| 10 |
| 11 #include "base/logging.h" |
| 12 #include "base/macros.h" |
| 13 #include "base/memory/ref_counted.h" |
| 14 |
| 15 namespace content { |
| 16 |
| 17 // Implements the pattern of a list of items, where added items are |
| 18 // tagged, you can tag all items, and you can retrieve the list of |
| 19 // items that are tagged, which removes the tag. |
| 20 // |
| 21 // For thread safety, operations on this object should be under an |
| 22 // external lock. An internally-locked version could be created, but |
| 23 // is not needed at the moment as users already lock. |
| 24 template <class ItemType> |
| 25 class TaggedList { |
| 26 public: |
| 27 typedef std::list<scoped_refptr<ItemType> > ItemList; |
| 28 |
| 29 TaggedList() {} |
| 30 |
| 31 void AddAndTag(ItemType* item) { |
| 32 items_.push_back(item); |
| 33 tagged_items_.push_back(item); |
| 34 } |
| 35 |
| 36 void TagAll() { |
| 37 tagged_items_ = items_; |
| 38 } |
| 39 |
| 40 const ItemList& Items() const { |
| 41 return items_; |
| 42 } |
| 43 |
| 44 // Retrieves the list of items with tags, and removes their tags. |
| 45 // |
| 46 // |dest| should be empty. |
| 47 void RetrieveAndClearTags(ItemList* dest) { |
| 48 DCHECK(dest->empty()); |
| 49 dest->swap(tagged_items_); |
| 50 } |
| 51 |
| 52 // Remove an item that matches a predicate. Will return a reference |
| 53 // to it if it is found. |
| 54 template <class UnaryPredicate> |
| 55 scoped_refptr<ItemType> Remove(UnaryPredicate predicate) { |
| 56 tagged_items_.remove_if(predicate); |
| 57 |
| 58 typename ItemList::iterator it = std::find_if( |
| 59 items_.begin(), items_.end(), predicate); |
| 60 if (it != items_.end()) { |
| 61 scoped_refptr<ItemType> removed_item = *it; |
| 62 items_.erase(it); |
| 63 return removed_item; |
| 64 } |
| 65 |
| 66 return NULL; |
| 67 } |
| 68 |
| 69 template <class UnaryPredicate> |
| 70 bool Contains(UnaryPredicate predicate) const { |
| 71 return std::find_if(items_.begin(), items_.end(), predicate) != |
| 72 items_.end(); |
| 73 } |
| 74 |
| 75 void Clear() { |
| 76 items_.clear(); |
| 77 tagged_items_.clear(); |
| 78 } |
| 79 |
| 80 bool IsEmpty() const { |
| 81 bool is_empty = items_.empty(); |
| 82 DCHECK(!is_empty || tagged_items_.empty()); |
| 83 return is_empty; |
| 84 } |
| 85 |
| 86 private: |
| 87 ItemList items_; |
| 88 ItemList tagged_items_; |
| 89 |
| 90 DISALLOW_COPY_AND_ASSIGN(TaggedList); |
| 91 }; |
| 92 |
| 93 } // namespace content |
| 94 |
| 95 #endif // CONTENT_RENDERER_MEDIA_TAGGED_LIST_H_ |
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