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| 1 // Copyright 2015 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 COMPONENTS_HTML_VIEWER_DISCARDABLE_MEMORY_ALLOCATOR_H_ | |
| 6 #define COMPONENTS_HTML_VIEWER_DISCARDABLE_MEMORY_ALLOCATOR_H_ | |
| 7 | |
| 8 #include <stddef.h> | |
| 9 | |
| 10 #include <list> | |
| 11 | |
| 12 #include "base/macros.h" | |
| 13 #include "base/memory/discardable_memory_allocator.h" | |
| 14 #include "base/synchronization/lock.h" | |
| 15 | |
| 16 namespace html_viewer { | |
| 17 | |
| 18 // A discarable memory allocator which will unallocate chunks on new | |
| 19 // allocations. | |
| 20 class DiscardableMemoryAllocator : public base::DiscardableMemoryAllocator { | |
| 21 public: | |
| 22 explicit DiscardableMemoryAllocator(size_t desired_max_memory); | |
| 23 ~DiscardableMemoryAllocator() override; | |
| 24 | |
| 25 // Overridden from DiscardableMemoryAllocator: | |
| 26 scoped_ptr<base::DiscardableMemory> AllocateLockedDiscardableMemory( | |
| 27 size_t size) override; | |
| 28 | |
| 29 private: | |
| 30 class DiscardableMemoryChunkImpl; | |
| 31 friend class DiscardableMemoryChunkImpl; | |
| 32 | |
| 33 // Called by DiscardableMemoryChunkImpl when they are unlocked. This puts them | |
| 34 // at the end of the live_unlocked_chunks_ list and passes an iterator to | |
| 35 // their position in the unlocked chunk list. | |
| 36 std::list<DiscardableMemoryChunkImpl*>::iterator NotifyUnlocked( | |
| 37 DiscardableMemoryChunkImpl* chunk); | |
| 38 | |
| 39 // Called by DiscardableMemoryChunkImpl when they are locked. This removes the | |
| 40 // passed in unlocked chunk list. | |
| 41 void NotifyLocked(std::list<DiscardableMemoryChunkImpl*>::iterator it); | |
| 42 | |
| 43 // Called by DiscardableMemoryChunkImpl when it's destructed. It must be | |
| 44 // unlocked, by definition. | |
| 45 void NotifyDestructed(std::list<DiscardableMemoryChunkImpl*>::iterator it); | |
| 46 | |
| 47 // The amount of memory we can allocate before we try to free unlocked | |
| 48 // chunks. We can go over this amount if all callers keep their discardable | |
| 49 // chunks locked. | |
| 50 const size_t desired_max_memory_; | |
| 51 | |
| 52 // Protects all members below, since this class can be called on the main | |
| 53 // thread and impl side painting raster threads. | |
| 54 base::Lock lock_; | |
| 55 | |
| 56 // A count of the sum of memory. Used to trigger discarding the oldest | |
| 57 // memory. | |
| 58 size_t total_live_memory_; | |
| 59 | |
| 60 // The number of locked chunks. | |
| 61 int locked_chunks_; | |
| 62 | |
| 63 // A linked list of unlocked allocated chunks so that the tail is most | |
| 64 // recently accessed chunks. | |
| 65 std::list<DiscardableMemoryChunkImpl*> live_unlocked_chunks_; | |
| 66 | |
| 67 DISALLOW_COPY_AND_ASSIGN(DiscardableMemoryAllocator); | |
| 68 }; | |
| 69 | |
| 70 } // namespace html_viewer | |
| 71 | |
| 72 #endif // COMPONENTS_HTML_VIEWER_DISCARDABLE_MEMORY_ALLOCATOR_H_ | |
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