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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 #include "content/browser/renderer_host/renderer_frame_manager.h"
      6 
      7 #include <algorithm>
      8 
      9 #include "base/logging.h"
     10 #include "base/memory/shared_memory.h"
     11 #include "base/sys_info.h"
     12 #include "content/common/host_shared_bitmap_manager.h"
     13 
     14 namespace content {
     15 
     16 RendererFrameManager* RendererFrameManager::GetInstance() {
     17   return Singleton<RendererFrameManager>::get();
     18 }
     19 
     20 void RendererFrameManager::AddFrame(RendererFrameManagerClient* frame,
     21                                     bool locked) {
     22   RemoveFrame(frame);
     23   if (locked)
     24     locked_frames_[frame] = 1;
     25   else
     26     unlocked_frames_.push_front(frame);
     27   CullUnlockedFrames();
     28 }
     29 
     30 void RendererFrameManager::RemoveFrame(RendererFrameManagerClient* frame) {
     31   std::map<RendererFrameManagerClient*, size_t>::iterator locked_iter =
     32       locked_frames_.find(frame);
     33   if (locked_iter != locked_frames_.end())
     34     locked_frames_.erase(locked_iter);
     35   unlocked_frames_.remove(frame);
     36 }
     37 
     38 void RendererFrameManager::LockFrame(RendererFrameManagerClient* frame) {
     39   std::list<RendererFrameManagerClient*>::iterator unlocked_iter =
     40     std::find(unlocked_frames_.begin(), unlocked_frames_.end(), frame);
     41   if (unlocked_iter != unlocked_frames_.end()) {
     42     DCHECK(locked_frames_.find(frame) == locked_frames_.end());
     43     unlocked_frames_.remove(frame);
     44     locked_frames_[frame] = 1;
     45   } else {
     46     DCHECK(locked_frames_.find(frame) != locked_frames_.end());
     47     locked_frames_[frame]++;
     48   }
     49 }
     50 
     51 void RendererFrameManager::UnlockFrame(RendererFrameManagerClient* frame) {
     52   DCHECK(locked_frames_.find(frame) != locked_frames_.end());
     53   size_t locked_count = locked_frames_[frame];
     54   DCHECK(locked_count);
     55   if (locked_count > 1) {
     56     locked_frames_[frame]--;
     57   } else {
     58     RemoveFrame(frame);
     59     unlocked_frames_.push_front(frame);
     60     CullUnlockedFrames();
     61   }
     62 }
     63 
     64 RendererFrameManager::RendererFrameManager() {
     65   max_number_of_saved_frames_ =
     66 #if defined(OS_ANDROID)
     67       1;
     68 #else
     69       std::min(5, 2 + (base::SysInfo::AmountOfPhysicalMemoryMB() / 256));
     70 #endif
     71   max_handles_ = base::SharedMemory::GetHandleLimit() / 8.0f;
     72 }
     73 
     74 RendererFrameManager::~RendererFrameManager() {}
     75 
     76 void RendererFrameManager::CullUnlockedFrames() {
     77   uint32 saved_frame_limit = max_number_of_saved_frames();
     78 
     79   if (unlocked_frames_.size() + locked_frames_.size() > 0) {
     80     float handles_per_frame =
     81         HostSharedBitmapManager::current()->AllocatedBitmapCount() * 1.0f /
     82         (unlocked_frames_.size() + locked_frames_.size());
     83 
     84     saved_frame_limit = std::max(
     85         1,
     86         static_cast<int>(std::min(static_cast<float>(saved_frame_limit),
     87                                   max_handles_ / handles_per_frame)));
     88   }
     89   while (!unlocked_frames_.empty() &&
     90          unlocked_frames_.size() + locked_frames_.size() > saved_frame_limit) {
     91     size_t old_size = unlocked_frames_.size();
     92     // Should remove self from list.
     93     unlocked_frames_.back()->EvictCurrentFrame();
     94     DCHECK_EQ(unlocked_frames_.size() + 1, old_size);
     95   }
     96 }
     97 
     98 }  // namespace content
     99