/src/mozilla-central/dom/media/systemservices/ShmemPool.cpp
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1 | | /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ |
2 | | /* vim: set sw=2 ts=8 et ft=cpp : */ |
3 | | /* This Source Code Form is subject to the terms of the Mozilla Public |
4 | | * License, v. 2.0. If a copy of the MPL was not distributed with this file, |
5 | | * You can obtain one at http://mozilla.org/MPL/2.0/. */ |
6 | | |
7 | | #include "mozilla/Assertions.h" |
8 | | #include "mozilla/Logging.h" |
9 | | #include "mozilla/ShmemPool.h" |
10 | | #include "mozilla/Move.h" |
11 | | |
12 | | namespace mozilla { |
13 | | |
14 | | ShmemPool::ShmemPool(size_t aPoolSize) |
15 | | : mMutex("mozilla::ShmemPool"), |
16 | | mPoolFree(aPoolSize) |
17 | | #ifdef DEBUG |
18 | | ,mMaxPoolUse(0) |
19 | | #endif |
20 | 0 | { |
21 | 0 | mShmemPool.SetLength(aPoolSize); |
22 | 0 | } |
23 | | |
24 | | mozilla::ShmemBuffer ShmemPool::GetIfAvailable(size_t aSize) |
25 | 0 | { |
26 | 0 | MutexAutoLock lock(mMutex); |
27 | 0 |
|
28 | 0 | // Pool is empty, don't block caller. |
29 | 0 | if (mPoolFree == 0) { |
30 | 0 | // This isn't initialized, so will be understood as an error. |
31 | 0 | return ShmemBuffer(); |
32 | 0 | } |
33 | 0 | |
34 | 0 | ShmemBuffer& res = mShmemPool[mPoolFree - 1]; |
35 | 0 |
|
36 | 0 | if (!res.mInitialized) { |
37 | 0 | LOG(("No free preallocated Shmem")); |
38 | 0 | return ShmemBuffer(); |
39 | 0 | } |
40 | 0 |
|
41 | 0 | MOZ_ASSERT(res.mShmem.IsWritable(), "Pool in Shmem is not writable?"); |
42 | 0 |
|
43 | 0 | if (res.mShmem.Size<uint8_t>() < aSize) { |
44 | 0 | LOG(("Free Shmem but not of the right size")); |
45 | 0 | return ShmemBuffer(); |
46 | 0 | } |
47 | 0 |
|
48 | 0 | mPoolFree--; |
49 | | #ifdef DEBUG |
50 | | size_t poolUse = mShmemPool.Length() - mPoolFree; |
51 | | if (poolUse > mMaxPoolUse) { |
52 | | mMaxPoolUse = poolUse; |
53 | | LOG(("Maximum ShmemPool use increased: %zu buffers", mMaxPoolUse)); |
54 | | } |
55 | | #endif |
56 | | return std::move(res); |
57 | 0 | } |
58 | | |
59 | | void ShmemPool::Put(ShmemBuffer&& aShmem) |
60 | 0 | { |
61 | 0 | MutexAutoLock lock(mMutex); |
62 | 0 | MOZ_ASSERT(mPoolFree < mShmemPool.Length()); |
63 | 0 | mShmemPool[mPoolFree] = std::move(aShmem); |
64 | 0 | mPoolFree++; |
65 | | #ifdef DEBUG |
66 | | size_t poolUse = mShmemPool.Length() - mPoolFree; |
67 | | if (poolUse > 0) { |
68 | | LOG_VERBOSE(("ShmemPool usage reduced to %zu buffers", poolUse)); |
69 | | } |
70 | | #endif |
71 | | } |
72 | | |
73 | | ShmemPool::~ShmemPool() |
74 | 0 | { |
75 | | #ifdef DEBUG |
76 | | for (size_t i = 0; i < mShmemPool.Length(); i++) { |
77 | | MOZ_ASSERT(!mShmemPool[i].Valid()); |
78 | | } |
79 | | #endif |
80 | | } |
81 | | |
82 | | } // namespace mozilla |