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// Copyright (c) 2017 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.
#ifndef GPU_COMMAND_BUFFER_CLIENT_CLIENT_TRANSFER_CACHE_H_
#define GPU_COMMAND_BUFFER_CLIENT_CLIENT_TRANSFER_CACHE_H_
#include <map>
#include "base/callback.h"
#include "base/optional.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 {
public:
class Client {
public:
virtual void IssueCreateTransferCacheEntry(GLuint entry_type,
GLuint entry_id,
GLuint handle_shm_id,
GLuint handle_shm_offset,
GLuint data_shm_id,
GLuint data_shm_offset,
GLuint data_size) = 0;
virtual void IssueDeleteTransferCacheEntry(GLuint entry_type,
GLuint entry_id) = 0;
virtual void IssueUnlockTransferCacheEntry(GLuint entry_type,
GLuint entry_id) = 0;
virtual CommandBufferHelper* cmd_buffer_helper() = 0;
virtual CommandBuffer* command_buffer() const = 0;
};
explicit ClientTransferCache(Client* client);
~ClientTransferCache();
// Adds a transfer cache entry with previously written memory.
void AddTransferCacheEntry(uint32_t type,
uint32_t id,
uint32_t shm_id,
uint32_t shm_offset,
size_t size);
// Similar to AddTransferCacheEntry() but doesn't use |client_| to trigger the
// creation of the service-side cache entry. Instead, it calls
// |create_entry_cb| passing a ClientDiscardableHandle which
// |create_entry_cb| can use to trigger the creation of an initially locked
// service-side cache entry using some external mechanism, e.g., an IPC
// message. This external mechanism should guarantee that it is safe for
// command buffer commands to reference the cache entry after
// |create_entry_cb| returns. Note that this function calls |create_entry_cb|
// before returning. |create_entry_cb| is not called if the
// ClientDiscardableHandle could not be created.
void StartTransferCacheEntry(
uint32_t type,
uint32_t id,
base::OnceCallback<void(ClientDiscardableHandle)> create_entry_cb);
// Map(of either type) must always be followed by an Unmap.
void* MapEntry(MappedMemoryManager* mapped_memory, size_t size);
void* MapTransferBufferEntry(TransferBufferInterface* transfer_buffer,
size_t size);
void UnmapAndCreateEntry(uint32_t type, uint32_t id);
bool LockEntry(uint32_t type, uint32_t id);
void UnlockEntries(const std::vector<std::pair<uint32_t, uint32_t>>& entries);
void DeleteEntry(uint32_t type, uint32_t id);
private:
using EntryKey = std::pair<uint32_t, uint32_t>;
ClientDiscardableHandle::Id FindDiscardableHandleId(const EntryKey& key);
ClientDiscardableHandle CreateDiscardableHandle(const EntryKey& key);
Client* const client_; // not owned --- client_ outlives this
base::Optional<ScopedMappedMemoryPtr> mapped_ptr_;
base::Optional<ScopedTransferBufferPtr> transfer_buffer_ptr_;
// Access to other members must always be done with |lock_| held.
base::Lock lock_;
ClientDiscardableManager discardable_manager_;
std::map<EntryKey, ClientDiscardableHandle::Id> discardable_handle_id_map_;
DISALLOW_COPY_AND_ASSIGN(ClientTransferCache);
};
} // namespace gpu
#endif // GPU_COMMAND_BUFFER_CLIENT_CLIENT_TRANSFER_CACHE_H_