gpu in-memory program cache implementation with a memory limit + lru eviction.

gpu/command_buffer/service/program_cache.h

+// Copyright (c) 2012 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_SERVICE_PROGRAM_CACHE_H_
+#define GPU_COMMAND_BUFFER_SERVICE_PROGRAM_CACHE_H_
+
+#include <map>
+#include <string>
+
+#include "base/hash_tables.h"
+#include "base/sha1.h"
+#include "gpu/command_buffer/common/gles2_cmd_format.h"
+#include "gpu/command_buffer/service/shader_manager.h"
+
+namespace gpu {
+namespace gles2 {
+
+// Program cache base class for caching linked gpu programs
+class GPU_EXPORT ProgramCache {
+ public:
+  static const size_t kHashLength = base::kSHA1Length;
+
+  typedef std::map<std::string, GLint> LocationMap;
+
+  enum CompiledShaderStatus {
+    COMPILATION_UNKNOWN,
+    COMPILATION_SUCCEEDED
+  };
+
+  enum LinkedProgramStatus {
+    LINK_UNKNOWN,
+    LINK_SUCCEEDED
+  };
+
+  enum ProgramLoadResult {
+    PROGRAM_LOAD_FAILURE,
+    PROGRAM_LOAD_SUCCESS
+  };
+
+  ProgramCache();
+  virtual ~ProgramCache();
+
+  CompiledShaderStatus GetShaderCompilationStatus(
+      const std::string& shader_src) const;
+  void ShaderCompilationSucceeded(const std::string& shader_src);
+
+  LinkedProgramStatus GetLinkedProgramStatus(
+      const std::string& untranslated_a,
+      const std::string& untranslated_b,
+      const LocationMap* bind_attrib_location_map) const;
+
+  // Loads the linked program from the cache.  If the program is not found or
+  // there was an error, PROGRAM_LOAD_FAILURE should be returned.
+  virtual ProgramLoadResult LoadLinkedProgram(
+      GLuint program,
+      ShaderManager::ShaderInfo* shader_a,
+      ShaderManager::ShaderInfo* shader_b,
+      const LocationMap* bind_attrib_location_map) const = 0;
+
+  // Saves the program into the cache.  If successful, the implementation should
+  // call LinkedProgramCacheSuccess.
+  virtual void SaveLinkedProgram(
+      GLuint program,
+      const ShaderManager::ShaderInfo* shader_a,
+      const ShaderManager::ShaderInfo* shader_b,
+      const LocationMap* bind_attrib_location_map) = 0;
+
+  // clears the cache
+  void Clear();
+
+  // Only for testing
+  void LinkedProgramCacheSuccess(const std::string& shader_a,
+                                 const std::string& shader_b,
+                                 const LocationMap* bind_attrib_location_map);
+
+ protected:
+  // called by implementing class after a shader was successfully cached
+  void LinkedProgramCacheSuccess(const std::string& program_hash,
+                                 const std::string& shader_a_hash,
+                                 const std::string& shader_b_hash);
+
+  // result is not null terminated
+  void ComputeShaderHash(const std::string& shader,
+                         char* result) const;
+
+  // result is not null terminated.  hashed shaders are expected to be
+  // kHashLength in length
+  void ComputeProgramHash(
+      const char* hashed_shader_0,
+      const char* hashed_shader_1,
+      const LocationMap* bind_attrib_location_map,
+      char* result) const;
+
+  void Evict(const std::string& program_hash,
+             const std::string& shader_0_hash,
+             const std::string& shader_1_hash);
+
+ private:
+  struct CompiledShaderInfo {
+    CompiledShaderInfo() : status(COMPILATION_UNKNOWN), ref_count(0) { }
+    explicit CompiledShaderInfo(CompiledShaderStatus status_)
+        : status(status_),
+          ref_count(0) { }
+
+    CompiledShaderStatus status;
+    size_t ref_count;
+  };
+
+  typedef base::hash_map<std::string,
+                         CompiledShaderInfo> CompileStatusMap;
+  typedef base::hash_map<std::string,
+                         LinkedProgramStatus> LinkStatusMap;
+
+  // called to clear the backend cache
+  virtual void ClearBackend() = 0;
+
+  CompileStatusMap shader_status_;
+  LinkStatusMap link_status_;
+
+  DISALLOW_COPY_AND_ASSIGN(ProgramCache);
+};
+
+}  // namespace gles2
+}  // namespace gpu
+
+#endif  // GPU_COMMAND_BUFFER_SERVICE_PROGRAM_CACHE_H_