src/media/cdm/ppapi/cdm_helpers.cc

   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 "media/cdm/ppapi/cdm_helpers.h"
   6
   7 #include <utility>
   8
   9 #include "base/basictypes.h"
  10 #include "base/compiler_specific.h"
  11 #include "build/build_config.h"
  12 #include "media/cdm/ppapi/api/content_decryption_module.h"
  13 #include "ppapi/c/pp_errors.h"
  14 #include "ppapi/c/pp_stdint.h"
  15 #include "ppapi/cpp/core.h"
  16 #include "ppapi/cpp/dev/buffer_dev.h"
  17 #include "ppapi/cpp/instance.h"
  18 #include "ppapi/cpp/logging.h"
  19 #include "ppapi/cpp/module.h"
  20
  21 namespace media {
  22
  23 cdm::Buffer* PpbBufferAllocator::Allocate(uint32_t capacity) {
  24   PP_DCHECK(pp::Module::Get()->core()->IsMainThread());
  25
  26   if (!capacity)
  27     return NULL;
  28
  29   pp::Buffer_Dev buffer;
  30   uint32_t buffer_id = 0;
  31
  32   // Reuse a buffer in the free list if there is one that fits |capacity|.
  33   // Otherwise, create a new one.
  34   FreeBufferMap::iterator found = free_buffers_.lower_bound(capacity);
  35   if (found == free_buffers_.end()) {
  36     // TODO(xhwang): Report statistics about how many new buffers are allocated.
  37     buffer = AllocateNewBuffer(capacity);
  38     if (buffer.is_null())
  39       return NULL;
  40     buffer_id = next_buffer_id_++;
  41   } else {
  42     buffer = found->second.second;
  43     buffer_id = found->second.first;
  44     free_buffers_.erase(found);
  45   }
  46
  47   allocated_buffers_.insert(std::make_pair(buffer_id, buffer));
  48
  49   return PpbBuffer::Create(buffer, buffer_id);
  50 }
  51
  52 void PpbBufferAllocator::Release(uint32_t buffer_id) {
  53   if (!buffer_id)
  54     return;
  55
  56   AllocatedBufferMap::iterator found = allocated_buffers_.find(buffer_id);
  57   if (found == allocated_buffers_.end())
  58     return;
  59
  60   pp::Buffer_Dev& buffer = found->second;
  61   free_buffers_.insert(
  62       std::make_pair(buffer.size(), std::make_pair(buffer_id, buffer)));
  63
  64   allocated_buffers_.erase(found);
  65 }
  66
  67 pp::Buffer_Dev PpbBufferAllocator::AllocateNewBuffer(uint32_t capacity) {
  68   // Always pad new allocated buffer so that we don't need to reallocate
  69   // buffers frequently if requested sizes fluctuate slightly.
  70   static const uint32_t kBufferPadding = 512;
  71
  72   // Maximum number of free buffers we can keep when allocating new buffers.
  73   static const uint32_t kFreeLimit = 3;
  74
  75   // Destroy the smallest buffer before allocating a new bigger buffer if the
  76   // number of free buffers exceeds a limit. This mechanism helps avoid ending
  77   // up with too many small buffers, which could happen if the size to be
  78   // allocated keeps increasing.
  79   if (free_buffers_.size() >= kFreeLimit)
  80     free_buffers_.erase(free_buffers_.begin());
  81
  82   // Creation of pp::Buffer_Dev is expensive! It involves synchronous IPC calls.
  83   // That's why we try to avoid AllocateNewBuffer() as much as we can.
  84   return pp::Buffer_Dev(instance_, capacity + kBufferPadding);
  85 }
  86
  87 VideoFrameImpl::VideoFrameImpl()
  88     : format_(cdm::kUnknownVideoFormat),
  89       frame_buffer_(NULL),
  90       timestamp_(0) {
  91   for (uint32_t i = 0; i < kMaxPlanes; ++i) {
  92     plane_offsets_[i] = 0;
  93     strides_[i] = 0;
  94   }
  95 }
  96
  97 VideoFrameImpl::~VideoFrameImpl() {
  98   if (frame_buffer_)
  99     frame_buffer_->Destroy();
 100 }
 101
 102 }  // namespace media