/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* 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 <math.h>

#include "nsString.h"

#include "nsIMemoryReporter.h"

#include "mozilla/ipc/SharedMemory.h"

#include "mozilla/Atomics.h"

namespace mozilla {

namespace ipc {

static Atomic<size_t> gShmemAllocated;

static Atomic<size_t> gShmemMapped;

class ShmemReporter final : public nsIMemoryReporter {

  ~ShmemReporter() {}

 public:

  NS_DECL_THREADSAFE_ISUPPORTS

  NS_IMETHOD

  CollectReports(nsIHandleReportCallback* aHandleReport, nsISupports* aData,

                 bool aAnonymize) override {

    MOZ_COLLECT_REPORT(

        "shmem-allocated", KIND_OTHER, UNITS_BYTES, gShmemAllocated,

        "Memory shared with other processes that is accessible (but not "

        "necessarily mapped).");

    MOZ_COLLECT_REPORT(

        "shmem-mapped", KIND_OTHER, UNITS_BYTES, gShmemMapped,

        "Memory shared with other processes that is mapped into the address "

        "space.");

    return NS_OK;

  }

};

NS_IMPL_ISUPPORTS(ShmemReporter, nsIMemoryReporter)

SharedMemory::SharedMemory() : mAllocSize(0), mMappedSize(0) {

  static Atomic<bool> registered;

  if (registered.compareExchange(false, true)) {

    RegisterStrongMemoryReporter(new ShmemReporter());

  }

}

/*static*/ size_t SharedMemory::PageAlignedSize(size_t aSize) {

  size_t pageSize = SystemPageSize();

  size_t nPagesNeeded = size_t(ceil(double(aSize) / double(pageSize)));

  return pageSize * nPagesNeeded;

}

void SharedMemory::Created(size_t aNBytes) {

  mAllocSize = aNBytes;

  gShmemAllocated += mAllocSize;

}

void SharedMemory::Mapped(size_t aNBytes) {

  mMappedSize = aNBytes;

  gShmemMapped += mMappedSize;

}

void SharedMemory::Unmapped() {

  MOZ_ASSERT(gShmemMapped >= mMappedSize, "Can't unmap more than mapped");

  gShmemMapped -= mMappedSize;

  mMappedSize = 0;

}

/*static*/ void SharedMemory::Destroyed() {

  MOZ_ASSERT(gShmemAllocated >= mAllocSize,

             "Can't destroy more than allocated");

  gShmemAllocated -= mAllocSize;

  mAllocSize = 0;

}

}  // namespace ipc

}  // namespace mozilla