client_transfer_cache.h | Explore in Territory

// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef GPU_COMMAND_BUFFER_CLIENT_CLIENT_TRANSFER_CACHE_H_
#define GPU_COMMAND_BUFFER_CLIENT_CLIENT_TRANSFER_CACHE_H_

#include <map>
#include <optional>

#include "base/functional/callback.h"
#include "base/memory/raw_ptr.h"
#include "base/synchronization/lock.h"
#include "gpu/command_buffer/client/client_discardable_manager.h"
#include "gpu/command_buffer/client/gles2_impl_export.h"
#include "gpu/command_buffer/client/gles2_interface.h"
#include "gpu/command_buffer/client/mapped_memory.h"
#include "gpu/command_buffer/client/transfer_buffer.h"

namespace gpu {
class MappedMemoryManager;

// ClientTransferCache allows for ClientTransferCacheEntries to be inserted
// into the cache, which will send them to the ServiceTransferCache, making
// them available for consumption in the GPU process. Typical usage is:
//   1) Create a new ClientTransferCacheEntry.
//   2) Map a memory allocation for the entry using either MapEntry() or
//      MapTransferBufferEntry().
//   3) Write the entry data to the mapped allocation using
//      ClientTransferCacheEntry::Serialize().
//   4) Unmap the allocation using UnmapAndCreateEntry(). This will ensure that
//      the entry starts locked and will trigger the creation of the
//      service-side cache entry.
//   5) Use the new entry's ID in one or more commands.
//   6) Unlock the entry via UnlockEntries() after dependent commands have been
//      issued.
//
// If an entry is needed again:
//   7) Attempt to lock the entry via LockEntry().
//      7a) If this fails, DeleteEntry() then go to (1).
//      7b) If this succeeds, go to (5).
//
// If an entry is no longer needed:
//   8) DeleteEntry().
//
// If the client wants to send the cache entry without using the |client| passed
// to the constructor, it should replace steps (2)-(4) with a call to
// StartTransferCacheEntry() and send the information needed to create the cache
// entry on the service side using some external mechanism, e.g., an IPC
// message.
//
// NOTE: The presence of locking on this class does not make it threadsafe.
// The underlying locking *only* allows calling LockTransferCacheEntry
// without holding the GL context lock. All other calls still require that
// the context lock be held.
class GLES2_IMPL_EXPORT ClientTransferCache { … };

}  // namespace gpu

#endif  // GPU_COMMAND_BUFFER_CLIENT_CLIENT_TRANSFER_CACHE_H_
chromium/gpu/command_buffer/client/client_transfer_cache.h
