/* -*- 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/. */

#ifndef GMPSharedMemManager_h_
#define GMPSharedMemManager_h_

#include "mozilla/ipc/Shmem.h"
#include "nsTArray.h"

namespace mozilla::gmp {

class GMPSharedMemManager;

class GMPSharedMem {
 public:
  typedef enum {
    kGMPFrameData = 0,
    kGMPEncodedData,
    kGMPNumTypes
  } GMPMemoryClasses;

  // This is a heuristic - max of 10 free in the Child pool, plus those
  // in-use for the encoder and decoder at the given moment and not yet
  // returned to the parent pool (which is not included).  If more than
  // this are needed, we presume the client has either crashed or hung
  // (perhaps temporarily).
  static const uint32_t kGMPBufLimit = 40;

  GMPSharedMem() {
    for (size_t i = 0; i < sizeof(mGmpAllocated) / sizeof(mGmpAllocated[0]);
         i++) {
      mGmpAllocated[i] = 0;
    }
  }
  virtual ~GMPSharedMem() = default;

  // Parent and child impls will differ here
  virtual void CheckThread() = 0;

 protected:
  friend class GMPSharedMemManager;

  nsTArray<ipc::Shmem> mGmpFreelist[GMPSharedMem::kGMPNumTypes];
  uint32_t mGmpAllocated[GMPSharedMem::kGMPNumTypes];
};

class GMPSharedMemManager {
 public:
  explicit GMPSharedMemManager(GMPSharedMem* aData) : mData(aData) {}
  virtual ~GMPSharedMemManager() = default;

  virtual bool MgrAllocShmem(GMPSharedMem::GMPMemoryClasses aClass,
                             size_t aSize, ipc::Shmem* aMem);
  virtual bool MgrDeallocShmem(GMPSharedMem::GMPMemoryClasses aClass,
                               ipc::Shmem& aMem);

  // So we can know if data is "piling up" for the plugin - I.e. it's hung or
  // crashed
  virtual uint32_t NumInUse(GMPSharedMem::GMPMemoryClasses aClass);

  // These have to be implemented using the AllocShmem/etc provided by the
  // IPDL-generated interfaces, so have the Parent/Child implement them.
  virtual bool Alloc(size_t aSize, ipc::Shmem* aMem) = 0;
  virtual void Dealloc(ipc::Shmem&& aMem) = 0;

 private:
  nsTArray<ipc::Shmem>& GetGmpFreelist(GMPSharedMem::GMPMemoryClasses aTypes) {
    return mData->mGmpFreelist[aTypes];
  }

  GMPSharedMem* mData;
};

}  // namespace mozilla::gmp

#endif  // GMPSharedMemManager_h_
