tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
Log | Files | Refs | README | LICENSE

GMPSharedMemManager.cpp (2466B)

      1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* This Source Code Form is subject to the terms of the Mozilla Public
      3 * License, v. 2.0. If a copy of the MPL was not distributed with this
      4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      5 
      6 #include "GMPSharedMemManager.h"
      7 
      8 #include "mozilla/ipc/SharedMemoryMapping.h"
      9 
     10 namespace mozilla::gmp {
     11 
     12 GMPSharedMemManager::~GMPSharedMemManager() {
     13 #ifdef DEBUG
     14  for (const auto& pool : mPool) {
     15    MOZ_ASSERT(pool.IsEmpty());
     16  }
     17 #endif
     18 }
     19 
     20 void GMPSharedMemManager::PurgeSmallerShmem(nsTArray<ipc::Shmem>& aPool,
     21                                            size_t aSize) {
     22  aPool.RemoveElementsBy([&](ipc::Shmem& shmem) {
     23    if (!shmem.IsWritable()) {
     24      MOZ_ASSERT_UNREACHABLE("Shmem must be writable!");
     25      return true;
     26    }
     27    if (shmem.Size<uint8_t>() >= aSize) {
     28      return false;
     29    }
     30    MgrDeallocShmem(shmem);
     31    return true;
     32  });
     33 }
     34 
     35 bool GMPSharedMemManager::MgrTakeShmem(GMPSharedMemClass aClass,
     36                                       ipc::Shmem* aMem) {
     37  MOZ_ASSERT(MgrIsOnOwningThread());
     38 
     39  auto& pool = mPool[size_t(aClass)];
     40  if (pool.IsEmpty()) {
     41    return false;
     42  }
     43 
     44  *aMem = pool.PopLastElement();
     45  return true;
     46 }
     47 
     48 bool GMPSharedMemManager::MgrTakeShmem(GMPSharedMemClass aClass, size_t aSize,
     49                                       ipc::Shmem* aMem) {
     50  MOZ_ASSERT(MgrIsOnOwningThread());
     51 
     52  auto& pool = mPool[size_t(aClass)];
     53  size_t alignedSize = ipc::shared_memory::PageAlignedSize(aSize);
     54  PurgeSmallerShmem(pool, alignedSize);
     55  if (pool.IsEmpty()) {
     56    return MgrAllocShmem(alignedSize, aMem);
     57  }
     58 
     59  *aMem = pool.PopLastElement();
     60  return true;
     61 }
     62 
     63 void GMPSharedMemManager::MgrGiveShmem(GMPSharedMemClass aClass,
     64                                       ipc::Shmem&& aMem) {
     65  MOZ_ASSERT(MgrIsOnOwningThread());
     66 
     67  if (!aMem.IsWritable()) {
     68    return;
     69  }
     70 
     71  auto& pool = mPool[size_t(aClass)];
     72  PurgeSmallerShmem(pool, aMem.Size<uint8_t>());
     73 
     74  if (pool.Length() >= kMaxPoolLength) {
     75    MgrDeallocShmem(aMem);
     76    return;
     77  }
     78 
     79  pool.AppendElement(std::move(aMem));
     80 }
     81 
     82 void GMPSharedMemManager::MgrPurgeShmems() {
     83  MOZ_ASSERT(MgrIsOnOwningThread());
     84 
     85  for (auto& pool : mPool) {
     86    for (auto& shmem : pool) {
     87      if (shmem.IsWritable()) {
     88        MgrDeallocShmem(shmem);
     89      } else {
     90        MOZ_ASSERT_UNREACHABLE("Shmem must be writable!");
     91      }
     92    }
     93    pool.Clear();
     94  }
     95 }
     96 
     97 }  // namespace mozilla::gmp