dom/broadcastchannel/BroadcastChannelService.cpp
author Mike Hommey <mh+mozilla@glandium.org>
Fri, 11 Jan 2019 16:01:15 +0000
changeset 453570 daf50f25895db073e44d50fecf2e4f6fe873865d
parent 448947 6f3709b3878117466168c40affa7bca0b60cf75b
child 454520 5f4630838d46dd81dadb13220a4af0da9e23a619
permissions -rw-r--r--
Bug 1519307 - Add a new project to build useful parts of breakpad independently. r=froydnj With `ac_add_options --enable-project=tools/crashreporter` in a mozconfig, `./mach build` builds minidump_stackwalk, dump_syms and fileid. One caveat is that due to limitation in how the build system works currently, it's cumbersome to keep dump_syms as a host program for Gecko, and to make it a target program for this project. For now, keep it as a host program. We're not going to use it on automation, but it's still convenient to have for quick local builds (I've had to resort to awful hacks downstream). Differential Revision: https://phabricator.services.mozilla.com/D16299

/* -*- 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 "BroadcastChannelService.h"
#include "BroadcastChannelParent.h"
#include "mozilla/dom/File.h"
#include "mozilla/dom/IPCBlobUtils.h"
#include "mozilla/ipc/BackgroundParent.h"

#ifdef XP_WIN
#undef PostMessage
#endif

namespace mozilla {

using namespace ipc;

namespace dom {

namespace {

BroadcastChannelService* sInstance = nullptr;

}  // namespace

BroadcastChannelService::BroadcastChannelService() {
  AssertIsOnBackgroundThread();

  // sInstance is a raw BroadcastChannelService*.
  MOZ_ASSERT(!sInstance);
  sInstance = this;
}

BroadcastChannelService::~BroadcastChannelService() {
  AssertIsOnBackgroundThread();
  MOZ_ASSERT(sInstance == this);
  MOZ_ASSERT(mAgents.Count() == 0);

  sInstance = nullptr;
}

// static
already_AddRefed<BroadcastChannelService>
BroadcastChannelService::GetOrCreate() {
  AssertIsOnBackgroundThread();

  RefPtr<BroadcastChannelService> instance = sInstance;
  if (!instance) {
    instance = new BroadcastChannelService();
  }
  return instance.forget();
}

void BroadcastChannelService::RegisterActor(
    BroadcastChannelParent* aParent, const nsAString& aOriginChannelKey) {
  AssertIsOnBackgroundThread();
  MOZ_ASSERT(aParent);

  nsTArray<BroadcastChannelParent*>* parents =
      mAgents.LookupForAdd(aOriginChannelKey).OrInsert([]() {
        return new nsTArray<BroadcastChannelParent*>();
      });

  MOZ_ASSERT(!parents->Contains(aParent));
  parents->AppendElement(aParent);
}

void BroadcastChannelService::UnregisterActor(
    BroadcastChannelParent* aParent, const nsAString& aOriginChannelKey) {
  AssertIsOnBackgroundThread();
  MOZ_ASSERT(aParent);

  if (auto entry = mAgents.Lookup(aOriginChannelKey)) {
    entry.Data()->RemoveElement(aParent);
    // remove the entry if the array is now empty
    if (entry.Data()->IsEmpty()) {
      entry.Remove();
    }
  } else {
    MOZ_CRASH("Invalid state");
  }
}

void BroadcastChannelService::PostMessage(BroadcastChannelParent* aParent,
                                          const ClonedMessageData& aData,
                                          const nsAString& aOriginChannelKey) {
  AssertIsOnBackgroundThread();
  MOZ_ASSERT(aParent);

  nsTArray<BroadcastChannelParent*>* parents;
  if (!mAgents.Get(aOriginChannelKey, &parents)) {
    MOZ_CRASH("Invalid state");
  }

  // We need to keep the array alive for the life-time of this operation.
  nsTArray<RefPtr<BlobImpl>> blobImpls;
  if (!aData.blobs().IsEmpty()) {
    blobImpls.SetCapacity(aData.blobs().Length());

    for (uint32_t i = 0, len = aData.blobs().Length(); i < len; ++i) {
      RefPtr<BlobImpl> impl = IPCBlobUtils::Deserialize(aData.blobs()[i]);

      MOZ_ASSERT(impl);
      blobImpls.AppendElement(impl);
    }
  }

  // For each parent actor, we notify the message.
  for (uint32_t i = 0; i < parents->Length(); ++i) {
    BroadcastChannelParent* parent = parents->ElementAt(i);
    MOZ_ASSERT(parent);

    if (parent == aParent) {
      continue;
    }

    // We need to have a copy of the data for this parent.
    ClonedMessageData newData(aData);
    MOZ_ASSERT(blobImpls.Length() == newData.blobs().Length());

    if (!blobImpls.IsEmpty()) {
      // Serialize Blob objects for this message.
      for (uint32_t i = 0, len = blobImpls.Length(); i < len; ++i) {
        nsresult rv = IPCBlobUtils::Serialize(blobImpls[i], parent->Manager(),
                                              newData.blobs()[i]);
        if (NS_WARN_IF(NS_FAILED(rv))) {
          return;
        }
      }
    }

    Unused << parent->SendNotify(newData);
  }
}

}  // namespace dom
}  // namespace mozilla