media/fuchsia/common/sysmem_buffer_pool.cc

// Copyright 2019 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "media/fuchsia/common/sysmem_buffer_pool.h"

#include <zircon/rights.h>
#include <algorithm>

#include "base/bind.h"
#include "base/fuchsia/default_context.h"
#include "base/fuchsia/fuchsia_logging.h"
#include "media/fuchsia/common/sysmem_buffer_reader.h"
#include "media/fuchsia/common/sysmem_buffer_writer.h"

namespace media {

SysmemBufferPool::Creator::Creator(
    fuchsia::sysmem::BufferCollectionPtr collection,
    std::vector<fuchsia::sysmem::BufferCollectionTokenPtr> shared_tokens)
    : collection_(std::move(collection)),
      shared_tokens_(std::move(shared_tokens)) {
  collection_.set_error_handler(
      [this](zx_status_t status) {
        ZX_DLOG(ERROR, status)
            << "Connection to BufferCollection was disconnected.";
        collection_.Unbind();

        if (create_cb_)
          std::move(create_cb_).Run(nullptr);
      });
}

SysmemBufferPool::Creator::~Creator() = default;

void SysmemBufferPool::Creator::Create(
    fuchsia::sysmem::BufferCollectionConstraints constraints,
    CreateCB create_cb) {
  DCHECK(!create_cb_);
  create_cb_ = std::move(create_cb);
  // BufferCollection needs to be synchronized to ensure that all token
  // duplicate requests have been processed and sysmem knows about all clients
  // that will be using this buffer collection.
  collection_->Sync([this, constraints = std::move(constraints)]() mutable {
    collection_->SetConstraints(true /* has constraints */,
                                std::move(constraints));

    DCHECK(create_cb_);
    std::move(create_cb_)
        .Run(std::make_unique<SysmemBufferPool>(std::move(collection_),
                                                std::move(shared_tokens_)));
  });
}

SysmemBufferPool::SysmemBufferPool(
    fuchsia::sysmem::BufferCollectionPtr collection,
    std::vector<fuchsia::sysmem::BufferCollectionTokenPtr> shared_tokens)
    : collection_(std::move(collection)),
      shared_tokens_(std::move(shared_tokens)) {
  collection_.set_error_handler([this](zx_status_t status) {
    ZX_LOG(ERROR, status) << "fuchsia.sysmem.BufferCollection disconnected.";
    OnError();
  });
}

SysmemBufferPool::~SysmemBufferPool() {
  if (collection_)
    collection_->Close();
}

fuchsia::sysmem::BufferCollectionTokenPtr SysmemBufferPool::TakeToken() {
  DCHECK(!shared_tokens_.empty());
  auto token = std::move(shared_tokens_.back());
  shared_tokens_.pop_back();
  return token;
}

void SysmemBufferPool::CreateReader(CreateReaderCB create_cb) {
  DCHECK(!create_reader_cb_);
  create_reader_cb_ = std::move(create_cb);
  collection_->WaitForBuffersAllocated(
      fit::bind_member(this, &SysmemBufferPool::OnBuffersAllocated));
}

void SysmemBufferPool::CreateWriter(CreateWriterCB create_cb) {
  DCHECK(!create_writer_cb_);
  create_writer_cb_ = std::move(create_cb);
  collection_->WaitForBuffersAllocated(
      fit::bind_member(this, &SysmemBufferPool::OnBuffersAllocated));
}

void SysmemBufferPool::OnBuffersAllocated(
    zx_status_t status,
    fuchsia::sysmem::BufferCollectionInfo_2 buffer_collection_info) {
  if (status != ZX_OK) {
    ZX_LOG(ERROR, status) << "Fail to allocate sysmem buffers.";
    OnError();
    return;
  }

  if (create_reader_cb_) {
    std::move(create_reader_cb_)
        .Run(SysmemBufferReader::Create(std::move(buffer_collection_info)));
  } else if (create_writer_cb_) {
    std::move(create_writer_cb_)
        .Run(SysmemBufferWriter::Create(std::move(buffer_collection_info)));
  }
}

void SysmemBufferPool::OnError() {
  collection_.Unbind();
  if (create_reader_cb_)
    std::move(create_reader_cb_).Run(nullptr);
  if (create_writer_cb_)
    std::move(create_writer_cb_).Run(nullptr);
}

BufferAllocator::BufferAllocator() {
  allocator_ = base::fuchsia::ComponentContextForCurrentProcess()
                   ->svc()
                   ->Connect<fuchsia::sysmem::Allocator>();

  allocator_.set_error_handler([](zx_status_t status) {
    // Just log a warning. We will handle BufferCollection the failure when
    // trying to create a new BufferCollection.
    ZX_DLOG(WARNING, status)
        << "The fuchsia.sysmem.Allocator channel was disconnected.";
  });
}

BufferAllocator::~BufferAllocator() = default;

std::unique_ptr<SysmemBufferPool::Creator>
BufferAllocator::MakeBufferPoolCreator(size_t num_of_tokens) {
  // Create a new sysmem buffer collection token for the allocated buffers.
  fuchsia::sysmem::BufferCollectionTokenPtr collection_token;
  allocator_->AllocateSharedCollection(collection_token.NewRequest());

  // Create collection token for sharing with other components.
  std::vector<fuchsia::sysmem::BufferCollectionTokenPtr> shared_tokens;
  for (size_t i = 0; i < num_of_tokens; i++) {
    fuchsia::sysmem::BufferCollectionTokenPtr token;
    collection_token->Duplicate(ZX_RIGHT_SAME_RIGHTS, token.NewRequest());
    shared_tokens.push_back(std::move(token));
  }

  fuchsia::sysmem::BufferCollectionPtr buffer_collection;

  // Convert the token to a BufferCollection connection.
  allocator_->BindSharedCollection(std::move(collection_token),
                                   buffer_collection.NewRequest());

  return std::make_unique<SysmemBufferPool::Creator>(
      std::move(buffer_collection), std::move(shared_tokens));
}

}  // namespace media