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

gpu/command_buffer/service/program_cache.cc

+// 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.
+
+#include "gpu/command_buffer/service/program_cache.h"
+
+#include "base/memory/scoped_ptr.h"
+
+namespace gpu {
+namespace gles2 {
+
+ProgramCache::ProgramCache() {}
+ProgramCache::~ProgramCache() {}
+
+void ProgramCache::Clear() {
+  shader_status_.clear();
+  link_status_.clear();
+  ClearBackend();
+}
+
+ProgramCache::CompiledShaderStatus ProgramCache::GetShaderCompilationStatus(
+    const std::string& shader_src) const {
+  char sha[kHashLength];
+  ComputeShaderHash(shader_src, sha);
+  const std::string sha_string(sha, kHashLength);
+
+  CompileStatusMap::const_iterator found = shader_status_.find(sha_string);
+
+  if (found == shader_status_.end()) {
+    return ProgramCache::COMPILATION_UNKNOWN;
+  } else {
+    return found->second.status;
+  }
+}
+
+void ProgramCache::ShaderCompilationSucceeded(
+    const std::string& shader_src) {
+  char sha[kHashLength];
+  ComputeShaderHash(shader_src, sha);
+  const std::string sha_string(sha, kHashLength);
+
+  CompileStatusMap::iterator it = shader_status_.find(sha_string);
+  if (it == shader_status_.end()) {
+    shader_status_[sha_string] = CompiledShaderInfo(COMPILATION_SUCCEEDED);
+  } else {
+    it->second.status = COMPILATION_SUCCEEDED;
+  }
+}
+
+ProgramCache::LinkedProgramStatus ProgramCache::GetLinkedProgramStatus(
+    const std::string& untranslated_a,
+    const std::string& untranslated_b,
+    const std::map<std::string, GLint>* bind_attrib_location_map) const {
+  char a_sha[kHashLength];
+  char b_sha[kHashLength];
+  ComputeShaderHash(untranslated_a, a_sha);
+  ComputeShaderHash(untranslated_b, b_sha);
+
+  char sha[kHashLength];
+  ComputeProgramHash(a_sha,
+                     b_sha,
+                     bind_attrib_location_map,
+                     sha);
+  const std::string sha_string(sha, kHashLength);
+
+  LinkStatusMap::const_iterator found = link_status_.find(sha_string);
+  if (found == link_status_.end()) {
+    return ProgramCache::LINK_UNKNOWN;
+  } else {
+    return found->second;
+  }
+}
+
+void ProgramCache::LinkedProgramCacheSuccess(
+    const std::string& shader_a,
+    const std::string& shader_b,
+    const LocationMap* bind_attrib_location_map) {
+  char a_sha[kHashLength];
+  char b_sha[kHashLength];
+  ComputeShaderHash(shader_a, a_sha);
+  ComputeShaderHash(shader_b, b_sha);
+  char sha[kHashLength];
+  ComputeProgramHash(a_sha,
+                     b_sha,
+                     bind_attrib_location_map,
+                     sha);
+  const std::string sha_string(sha, kHashLength);
+
+  LinkedProgramCacheSuccess(sha_string,
+                            std::string(a_sha, kHashLength),
+                            std::string(b_sha, kHashLength));
+}
+
+void ProgramCache::LinkedProgramCacheSuccess(const std::string& program_hash,
+                                             const std::string& shader_a_hash,
+                                             const std::string& shader_b_hash) {
+  link_status_[program_hash] = LINK_SUCCEEDED;
+  shader_status_[shader_a_hash].ref_count++;
+  shader_status_[shader_b_hash].ref_count++;
+}
+
+void ProgramCache::ComputeShaderHash(const std::string& str,
+                                     char* result) const {
+  base::SHA1HashBytes(reinterpret_cast<const unsigned char*>(str.c_str()),
+                      str.length(), reinterpret_cast<unsigned char*>(result));
+}
+
+void ProgramCache::Evict(const std::string& program_hash,
+                         const std::string& shader_0_hash,
+                         const std::string& shader_1_hash) {
+  CompileStatusMap::iterator info0 = shader_status_.find(shader_0_hash);
+  CompileStatusMap::iterator info1 = shader_status_.find(shader_1_hash);
+  DCHECK(info0 != shader_status_.end());
+  DCHECK(info1 != shader_status_.end());
+  DCHECK(info0->second.ref_count > 0);
+  DCHECK(info1->second.ref_count > 0);
+  if (--info0->second.ref_count <= 0) {
+    shader_status_.erase(shader_0_hash);
+  }
+  if (--info1->second.ref_count <= 0) {
+    shader_status_.erase(shader_1_hash);
+  }
+  link_status_.erase(program_hash);
+}
+
+namespace {
+size_t CalculateMapSize(const std::map<std::string, GLint>* map) {
+  if (!map) {
+    return 0;
+  }
+  std::map<std::string, GLint>::const_iterator it;
+  size_t total = 0;
+  for (it = map->begin(); it != map->end(); ++it) {
+    total += 4 + it->first.length();
+  }
+  return total;
+}
+}  // anonymous namespace
+
+void ProgramCache::ComputeProgramHash(
+    const char* hashed_shader_0,
+    const char* hashed_shader_1,
+    const std::map<std::string, GLint>* bind_attrib_location_map,
+    char* result) const {
+  const size_t shader0_size = kHashLength;
+  const size_t shader1_size = kHashLength;
+  const size_t map_size = CalculateMapSize(bind_attrib_location_map);
+  const size_t total_size = shader0_size + shader1_size + map_size;
+
+  scoped_array<unsigned char> buffer(new unsigned char[total_size]);
+  memcpy(buffer.get(), hashed_shader_0, shader0_size);
+  memcpy(&buffer[shader0_size], hashed_shader_1, shader1_size);
+  if (map_size != 0) {
+    // copy our map
+    size_t current_pos = shader0_size + shader1_size;
+    std::map<std::string, GLint>::const_iterator it;
+    for (it = bind_attrib_location_map->begin();
+         it != bind_attrib_location_map->end();
+         ++it) {
+      const size_t name_size = it->first.length();
+      memcpy(&buffer.get()[current_pos], it->first.c_str(), name_size);
+      current_pos += name_size;
+      const GLint value = it->second;
+      buffer[current_pos++] = value >> 24;
+      buffer[current_pos++] = value >> 16;
+      buffer[current_pos++] = value >> 8;
+      buffer[current_pos++] = value;
+    }
+  }
+  base::SHA1HashBytes(buffer.get(),
+                      total_size, reinterpret_cast<unsigned char*>(result));
+}
+
+}  // namespace gles2
+}  // namespace gpu