src/devices/sysmem/drivers/sysmem/buffer_collection.h

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

#ifndef SRC_DEVICES_SYSMEM_DRIVERS_SYSMEM_BUFFER_COLLECTION_H_
#define SRC_DEVICES_SYSMEM_DRIVERS_SYSMEM_BUFFER_COLLECTION_H_

#include <fuchsia/sysmem/c/fidl.h>
#include <fuchsia/sysmem/llcpp/fidl.h>
#include <fuchsia/sysmem2/llcpp/fidl.h>
#include <lib/fidl-async-2/fidl_server.h>
#include <lib/fidl-async-2/fidl_struct.h>
#include <lib/fidl-async-2/simple_binding.h>
#include <lib/fidl/internal.h>
#include <lib/fidl/llcpp/heap_allocator.h>

#include <list>

#include "logging.h"
#include "logical_buffer_collection.h"

namespace sysmem_driver {

class BufferCollection
    : public FidlServer<BufferCollection,
                        SimpleBinding<BufferCollection, fuchsia_sysmem_BufferCollection_ops_t,
                                      fuchsia_sysmem_BufferCollection_dispatch>,
                        vLog> {
 public:
  ~BufferCollection();

  //
  // fuchsia.sysmem.BufferCollection interface methods
  //

  zx_status_t SetEventSink(zx_handle_t buffer_collection_events_client);
  zx_status_t Sync(fidl_txn_t* txn);
  zx_status_t SetConstraints(bool has_constraints,
                             const fuchsia_sysmem_BufferCollectionConstraints* constraints);
  zx_status_t WaitForBuffersAllocated(fidl_txn_t* txn);
  zx_status_t CheckBuffersAllocated(fidl_txn_t* txn);
  zx_status_t CloseSingleBuffer(uint64_t buffer_index);
  zx_status_t AllocateSingleBuffer(uint64_t buffer_index);
  zx_status_t WaitForSingleBufferAllocated(uint64_t buffer_index, fidl_txn_t* txn);
  zx_status_t CheckSingleBufferAllocated(uint64_t buffer_index);
  zx_status_t Close();
  zx_status_t SetName(uint32_t priority, const char* name_data, size_t name_size);
  zx_status_t SetDebugClientInfo(const char* name_data, size_t name_size, uint64_t id);
  zx_status_t SetConstraintsAuxBuffers(
      const fuchsia_sysmem_BufferCollectionConstraintsAuxBuffers* constraints_aux_buffers);
  zx_status_t GetAuxBuffers(fidl_txn_t* txn_param);

  //
  // LogicalBufferCollection uses these:
  //

  void OnBuffersAllocated();

  bool has_constraints();

  // has_constraints() must be true to call this.
  //
  // this can only be called if TakeConstraints() hasn't been called yet.
  const llcpp::fuchsia::sysmem2::BufferCollectionConstraints::Builder& constraints();

  // has_constraints() must be true to call this.
  //
  // this can only be called once
  llcpp::fuchsia::sysmem2::BufferCollectionConstraints::Builder TakeConstraints();

  LogicalBufferCollection* parent();

  fbl::RefPtr<LogicalBufferCollection> parent_shared();

  bool is_done();

  const std::string& debug_name() const { return debug_info_.name; }
  uint64_t debug_id() const { return debug_info_.id; }

 private:
  using V1CBufferCollectionInfo = FidlStruct<fuchsia_sysmem_BufferCollectionInfo_2,
                                             llcpp::fuchsia::sysmem::BufferCollectionInfo_2>;

  friend class FidlServer;

  explicit BufferCollection(fbl::RefPtr<LogicalBufferCollection> parent);

  // The rights attenuation mask driven by usage, so that read-only usage
  // doesn't get write, etc.
  uint32_t GetUsageBasedRightsAttenuation();

  uint32_t GetClientVmoRights();
  uint32_t GetClientAuxVmoRights();
  void MaybeCompleteWaitForBuffersAllocated();

  // Hide parent method.
  void FailAsync(zx_status_t status, const char* format, ...);

  fit::result<llcpp::fuchsia::sysmem2::BufferCollectionInfo::Builder> CloneResultForSendingV2(
      const llcpp::fuchsia::sysmem2::BufferCollectionInfo& buffer_collection_info);

  fit::result<V1CBufferCollectionInfo> CloneResultForSendingV1(
      const llcpp::fuchsia::sysmem2::BufferCollectionInfo& buffer_collection_info);
  fit::result<BufferCollection::V1CBufferCollectionInfo> CloneAuxBuffersResultForSendingV1(
      const llcpp::fuchsia::sysmem2::BufferCollectionInfo& buffer_collection_info);

  static const fuchsia_sysmem_BufferCollection_ops_t kOps;

  fbl::RefPtr<LogicalBufferCollection> parent_;

  LogicalBufferCollection::FidlAllocator& allocator_;

  // Client end of a BufferCollectionEvents channel, for the local server to
  // send events to the remote client.  All of the messages in this interface
  // are one-way with no response, so sending an event doesn't block the
  // server thread.
  //
  // This may remain non-set if SetEventSink() is never used by a client.  A
  // client may send SetEventSink() up to once.
  //
  // For example:
  // fuchsia_sysmem_BufferCollectionEventsOnBuffersAllocated(
  //     events_.get(), ...);
  zx::channel events_;

  // Constraints as set by:
  //
  // v1:
  //     optional SetConstraintsAuxBuffers
  //     SetConstraints()
  //
  // v2 (TODO):
  //     SetConstraints()
  //
  // Either way, the constraints here are in v2 form.
  std::optional<llcpp::fuchsia::sysmem2::BufferCollectionConstraints::Builder> constraints_;

  // Stash BufferUsage aside for benefit of GetUsageBasedRightsAttenuation() despite
  // TakeConstraints().
  std::optional<llcpp::fuchsia::sysmem2::BufferUsage> usage_;

  // Temporarily holds fuchsia.sysmem.BufferCollectionConstraintsAuxBuffers until SetConstraints()
  // arrives.
  std::optional<llcpp::fuchsia::sysmem::BufferCollectionConstraintsAuxBuffers>
      constraints_aux_buffers_;

  // FIDL protocol enforcement.
  bool is_set_constraints_seen_ = false;
  bool is_set_constraints_aux_buffers_seen_ = false;

  // The rights attenuation mask driven by BufferCollectionToken::Duplicate()
  // rights_attenuation_mask parameter(s) as the token is duplicated,
  // potentially via multiple participants.
  //
  // TODO(fxbug.dev/50578): Finish plumbing this.
  uint32_t client_rights_attenuation_mask_ = std::numeric_limits<uint32_t>::max();

  std::list<std::pair</*async_id*/ uint64_t, std::unique_ptr<BindingType::Txn>>>
      pending_wait_for_buffers_allocated_;

  bool is_done_ = false;

  LogicalBufferCollection::ClientInfo debug_info_;

  inspect::Node node_;
  inspect::UintProperty debug_id_property_;
  inspect::StringProperty debug_name_property_;
};

}  // namespace sysmem_driver

#endif  // SRC_DEVICES_SYSMEM_DRIVERS_SYSMEM_BUFFER_COLLECTION_H_