/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "GMPSharedMemManager.h"

#include "GMPMessageUtils.h"

#include "mozilla/ipc/SharedMemory.h"

#include "mozilla/StaticPtr.h"

#include "mozilla/ClearOnShutdown.h"

namespace mozilla {

namespace gmp {

// Really one set of pools on each side of the plugin API.

// YUV buffers go from Encoder parent to child; pool there, and then return

// with Decoded() frames to the Decoder parent and goes into the parent pool.

// Compressed (encoded) data goes from the Decoder parent to the child;

// pool there, and then return with Encoded() frames and goes into the parent

// pool.

bool

GMPSharedMemManager::MgrAllocShmem(GMPSharedMem::GMPMemoryClasses aClass, size_t aSize,

                                   ipc::Shmem::SharedMemory::SharedMemoryType aType,

                                   ipc::Shmem* aMem)

{

  mData->CheckThread();

  // first look to see if we have a free buffer large enough

  for (uint32_t i = 0; i < GetGmpFreelist(aClass).Length(); i++) {

    MOZ_ASSERT(GetGmpFreelist(aClass)[i].IsWritable());

    if (aSize <= GetGmpFreelist(aClass)[i].Size<uint8_t>()) {

      *aMem = GetGmpFreelist(aClass)[i];

      GetGmpFreelist(aClass).RemoveElementAt(i);

      return true;

    }

  }

  // Didn't find a buffer free with enough space; allocate one

  size_t pagesize = ipc::SharedMemory::SystemPageSize();

  aSize = (aSize + (pagesize-1)) & ~(pagesize-1); // round up to page size

  bool retval = Alloc(aSize, aType, aMem);

  if (retval) {

    // The allocator (or NeedsShmem call) should never return less than we ask for...

    MOZ_ASSERT(aMem->Size<uint8_t>() >= aSize);

    mData->mGmpAllocated[aClass]++;

  }

  return retval;

}

bool

GMPSharedMemManager::MgrDeallocShmem(GMPSharedMem::GMPMemoryClasses aClass, ipc::Shmem& aMem)

{

  mData->CheckThread();

  size_t size = aMem.Size<uint8_t>();

  size_t total = 0;

  // XXX Bug NNNNNNN Until we put better guards on ipc::shmem, verify we

  // weren't fed an shmem we already had.

  for (uint32_t i = 0; i < GetGmpFreelist(aClass).Length(); i++) {

    if (NS_WARN_IF(aMem == GetGmpFreelist(aClass)[i])) {

      // Safest to crash in this case; should never happen in normal

      // operation.

      MOZ_CRASH("Deallocating Shmem we already have in our cache!");

      //return true;

    }

  }

  // XXX This works; there are better pool algorithms.  We need to avoid

  // "falling off a cliff" with too low a number

  if (GetGmpFreelist(aClass).Length() > 10) {

    Dealloc(GetGmpFreelist(aClass)[0]);

    GetGmpFreelist(aClass).RemoveElementAt(0);

    // The allocation numbers will be fubar on the Child!

    mData->mGmpAllocated[aClass]--;

  }

  for (uint32_t i = 0; i < GetGmpFreelist(aClass).Length(); i++) {

    MOZ_ASSERT(GetGmpFreelist(aClass)[i].IsWritable());

    total += GetGmpFreelist(aClass)[i].Size<uint8_t>();

    if (size < GetGmpFreelist(aClass)[i].Size<uint8_t>()) {

      GetGmpFreelist(aClass).InsertElementAt(i, aMem);

      return true;

    }

  }

  GetGmpFreelist(aClass).AppendElement(aMem);

  return true;

}

uint32_t

GMPSharedMemManager::NumInUse(GMPSharedMem::GMPMemoryClasses aClass)

{

  return mData->mGmpAllocated[aClass] - GetGmpFreelist(aClass).Length();

}

} // namespace gmp

} // namespace mozilla