Allow textures to be moved from one GL context group to another.

gpu/command_buffer/service/mailbox_manager.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/mailbox_manager.h"
+
+#include "base/rand_util.h"
+#include "crypto/hmac.h"
+#include "gpu/command_buffer/service/gl_utils.h"
+#include "gpu/command_buffer/service/texture_definition.h"
+
+namespace gpu {
+namespace gles2 {
+
+MailboxManager::MailboxManager()
+    : hmac_(crypto::HMAC::SHA256),
+      textures_(std::ptr_fun(&MailboxManager::TargetNameLess)) {
+  unsigned char private_key[GL_MAILBOX_SIZE_CHROMIUM / 2];
+  base::RandBytes(private_key, sizeof(private_key));

[apatrick_chromium, 2012/04/27 22:31:58]

This actually is a cryptographically strong on all platforms.

+  bool success = hmac_.Init(private_key, sizeof(private_key));
+  DCHECK(success);
+}
+
+MailboxManager::~MailboxManager() {
+}
+
+void MailboxManager::GenerateMailboxName(MailboxName* name) {
+  base::RandBytes(name->key, sizeof(name->key));
+  SignMailboxName(name);
+}
+
+TextureDefinition* MailboxManager::ConsumeTexture(unsigned target,
+                                                  const MailboxName& name) {
+  if (!IsMailboxNameValid(name))
+    return NULL;
+
+  TextureDefinitionMap::iterator it =
+      textures_.find(TargetName(target, name));
+  if (it == textures_.end()) {
+    NOTREACHED();
+    return NULL;
+  }
+
+  TextureDefinition* definition = it->second.definition.release();
+  textures_.erase(it);
+
+  return definition;
+}
+
+bool MailboxManager::ProduceTexture(unsigned target,
+                                    const MailboxName& name,
+                                    TextureDefinition* definition,
+                                    TextureManager* owner) {
+  if (!IsMailboxNameValid(name))
+    return false;
+
+  TextureDefinitionMap::iterator it =
+      textures_.find(TargetName(target, name));
+  if (it != textures_.end()) {
+    NOTREACHED();
+    GLuint service_id = it->second.definition->ReleaseServiceId();
+    glDeleteTextures(1, &service_id);
+    it->second = OwnedTextureDefinition(definition, owner);
+  } else {
+    textures_.insert(std::make_pair(
+        TargetName(target, name),
+        OwnedTextureDefinition(definition, owner)));
+  }
+
+  return true;
+}
+
+void MailboxManager::DestroyOwnedTextures(TextureManager* owner,
+                                          bool have_context) {
+  TextureDefinitionMap::iterator it = textures_.begin();
+  while (it != textures_.end()) {
+    TextureDefinitionMap::iterator current_it = it;
+    ++it;
+    if (current_it->second.owner == owner) {
+      NOTREACHED();
+      GLuint service_id = current_it->second.definition->ReleaseServiceId();
+      if (have_context)
+        glDeleteTextures(1, &service_id);
+      textures_.erase(current_it);
+    }
+  }
+}
+
+void MailboxManager::SignMailboxName(MailboxName* name) {
+  bool success = hmac_.Sign(
+      base::StringPiece(reinterpret_cast<char*>(name->key), sizeof(name->key)),
+      reinterpret_cast<unsigned char*>(name->signature),
+      sizeof(name->signature));
+  DCHECK(success);
+}
+
+bool MailboxManager::IsMailboxNameValid(const MailboxName& name) {
+  return hmac_.Verify(
+      base::StringPiece(reinterpret_cast<const char*>(name.key),
+          sizeof(name.key)),
+      base::StringPiece(reinterpret_cast<const char*>(name.signature),
+          sizeof(name.signature)));
+}
+
+MailboxManager::TargetName::TargetName(unsigned target, const MailboxName& name)
+    : target(target),
+      name(name) {
+}
+
+bool MailboxManager::TargetNameLess(MailboxManager::TargetName lhs,
+                                    MailboxManager::TargetName rhs) {
+  return memcmp(&lhs, &rhs, sizeof(lhs)) < 0;
+}
+
+MailboxManager::OwnedTextureDefinition::OwnedTextureDefinition(
+    TextureDefinition* definition,
+    TextureManager* owner)
+    : definition(definition),
+      owner(owner) {
+}
+
+MailboxManager::OwnedTextureDefinition::~OwnedTextureDefinition() {
+}
+}  // namespace gles2
+}  // namespace gpu