Changes to WebDatabaseObserverImpl and SimpleDatabaseSystem required to have a chance of working properly with v8 isolates. With isolates the database related interfaces will be called on multiple threads and the previous impl was not put together with that in mind.

BUG=none
TEST=existing tests pass (no way to test with isolates yet)
Review URL: http://codereview.chromium.org/6677088

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@80218 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 167 insertions, 2 deletions

diff --git a/webkit/database/database_connections.cc b/webkit/database/database_connections.cc
index 05efb1e..612f73b4 100644
--- a/webkit/database/database_connections.cc
+++ b/webkit/database/database_connections.cc
@@ -1,10 +1,13 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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 "webkit/database/database_connections.h"
 
+#include "base/auto_reset.h"
 #include "base/logging.h"
+#include "base/message_loop.h"
+#include "base/message_loop_proxy.h"
 
 namespace webkit_database {
 
@@ -84,4 +87,53 @@ void DatabaseConnections::RemoveConnectionsHelper(
   }
 }
 
+DatabaseConnectionsWrapper::DatabaseConnectionsWrapper()
+    : waiting_for_dbs_to_close_(false),
+      main_thread_(base::MessageLoopProxy::CreateForCurrentThread()) {
+}
+
+DatabaseConnectionsWrapper::~DatabaseConnectionsWrapper() {
+}
+
+void DatabaseConnectionsWrapper::WaitForAllDatabasesToClose() {
+  // We assume that new databases won't be open while we're waiting.
+  DCHECK(main_thread_->BelongsToCurrentThread());
+  if (HasOpenConnections()) {
+    AutoReset<bool> auto_reset(&waiting_for_dbs_to_close_, true);
+    MessageLoop::ScopedNestableTaskAllower nestable(MessageLoop::current());
+    MessageLoop::current()->Run();
+  }
+}
+
+bool DatabaseConnectionsWrapper::HasOpenConnections() {
+  DCHECK(main_thread_->BelongsToCurrentThread());
+  base::AutoLock auto_lock(open_connections_lock_);
+  return !open_connections_.IsEmpty();
+}
+
+void DatabaseConnectionsWrapper::AddOpenConnection(
+    const string16& origin_identifier,
+    const string16& database_name) {
+  // We add to the collection immediately on any thread.
+  base::AutoLock auto_lock(open_connections_lock_);
+  open_connections_.AddConnection(origin_identifier, database_name);
+}
+
+void DatabaseConnectionsWrapper::RemoveOpenConnection(
+    const string16& origin_identifier,
+    const string16& database_name) {
+  // But only remove from the collection on the main thread
+  // so we can handle the waiting_for_dbs_to_close_ case.
+  if (!main_thread_->BelongsToCurrentThread()) {
+    main_thread_->PostTask(FROM_HERE, NewRunnableMethod(
+        this, &DatabaseConnectionsWrapper::RemoveOpenConnection,
+        origin_identifier, database_name));
+    return;
+  }
+  base::AutoLock auto_lock(open_connections_lock_);
+  open_connections_.RemoveConnection(origin_identifier, database_name);
+  if (waiting_for_dbs_to_close_ && open_connections_.IsEmpty())
+    MessageLoop::current()->Quit();
+}
+
 }  // namespace webkit_database
diff --git a/webkit/database/database_connections.h b/webkit/database/database_connections.h
index 433bb3f..6a594b2 100644
--- a/webkit/database/database_connections.h
+++ b/webkit/database/database_connections.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -8,7 +8,13 @@
 #include <map>
 #include <vector>
 
+#include "base/memory/ref_counted.h"
 #include "base/string16.h"
+#include "base/synchronization/lock.h"
+
+namespace base {
+class MessageLoopProxy;
+}
 
 namespace webkit_database {
 
@@ -40,6 +46,34 @@ class DatabaseConnections {
                                int num_connections);
 };
 
+// A wrapper class that provides thread-safety and the
+// ability to wait until all connections have closed.
+// Intended for use in renderer processes.
+class DatabaseConnectionsWrapper
+    : public base::RefCountedThreadSafe<DatabaseConnectionsWrapper> {
+ public:
+  DatabaseConnectionsWrapper();
+
+  // The Wait and Has methods should only be called on the
+  // main thread (the thread on which the wrapper is constructed).
+  void WaitForAllDatabasesToClose();
+  bool HasOpenConnections();
+
+  // Add and Remove may be called on any thread.
+  void AddOpenConnection(const string16& origin_identifier,
+                         const string16& database_name);
+  void RemoveOpenConnection(const string16& origin_identifier,
+                            const string16& database_name);
+ private:
+  ~DatabaseConnectionsWrapper();
+  friend class base::RefCountedThreadSafe<DatabaseConnectionsWrapper>;
+
+  bool waiting_for_dbs_to_close_;
+  base::Lock open_connections_lock_;
+  DatabaseConnections open_connections_;
+  scoped_refptr<base::MessageLoopProxy> main_thread_;
+};
+
 }  // namespace webkit_database
 
 #endif  // WEBKIT_DATABASE_DATABASE_CONNECTIONS_H_
diff --git a/webkit/database/database_connections_unittest.cc b/webkit/database/database_connections_unittest.cc
new file mode 100644
index 0000000..1b3ef34
--- /dev/null
+++ b/webkit/database/database_connections_unittest.cc
@@ -0,0 +1,79 @@
+// Copyright (c) 2011 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 "base/message_loop.h"
+#include "base/task.h"
+#include "base/threading/thread.h"
+#include "base/utf_string_conversions.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "webkit/database/database_connections.h"
+
+namespace webkit_database {
+
+namespace {
+
+void RemoveConnectionTask(
+    const string16& origin_id, const string16& database_name,
+    scoped_refptr<DatabaseConnectionsWrapper> obj,
+    bool* did_task_execute) {
+  *did_task_execute = true;
+  obj->RemoveOpenConnection(origin_id, database_name);
+}
+
+void ScheduleRemoveConnectionTask(
+    base::Thread* thread,  const string16& origin_id,
+    const string16& database_name,
+    scoped_refptr<DatabaseConnectionsWrapper> obj,
+    bool* did_task_execute) {
+  thread->message_loop()->PostTask(FROM_HERE,
+      NewRunnableFunction(RemoveConnectionTask,
+                          origin_id, database_name, obj, did_task_execute));
+}
+
+}  // anonymous namespace
+
+TEST(DatabaseConnectionsTest, DatabaseConnectionsWrapperTest) {
+  string16 kOriginId(ASCIIToUTF16("origin_id"));
+  string16 kName(ASCIIToUTF16("database_name"));
+
+  scoped_refptr<DatabaseConnectionsWrapper> obj(
+      new DatabaseConnectionsWrapper);
+  EXPECT_FALSE(obj->HasOpenConnections());
+  obj->AddOpenConnection(kOriginId, kName);
+  EXPECT_TRUE(obj->HasOpenConnections());
+  obj->AddOpenConnection(kOriginId, kName);
+  EXPECT_TRUE(obj->HasOpenConnections());
+  obj->RemoveOpenConnection(kOriginId, kName);
+  EXPECT_TRUE(obj->HasOpenConnections());
+  obj->RemoveOpenConnection(kOriginId, kName);
+  EXPECT_FALSE(obj->HasOpenConnections());
+  obj->WaitForAllDatabasesToClose();  // should return immediately
+
+  // Test WaitForAllDatabasesToClose with the last connection
+  // being removed on the current thread.
+  obj->AddOpenConnection(kOriginId, kName);
+  bool did_task_execute = false;
+  MessageLoop::current()->PostTask(FROM_HERE,
+      NewRunnableFunction(&RemoveConnectionTask,
+                          kOriginId, kName, obj, &did_task_execute));
+  obj->WaitForAllDatabasesToClose();  // should return after the task executes
+  EXPECT_TRUE(did_task_execute);
+  EXPECT_FALSE(obj->HasOpenConnections());
+
+  // Test WaitForAllDatabasesToClose with the last connection
+  // being removed on another thread.
+  obj->AddOpenConnection(kOriginId, kName);
+  base::Thread thread("WrapperTestThread");
+  thread.Start();
+  did_task_execute = false;
+  MessageLoop::current()->PostTask(FROM_HERE,
+      NewRunnableFunction(ScheduleRemoveConnectionTask,
+                          &thread, kOriginId, kName,
+                          obj, &did_task_execute));
+  obj->WaitForAllDatabasesToClose();  // should return after the task executes
+  EXPECT_TRUE(did_task_execute);
+  EXPECT_FALSE(obj->HasOpenConnections());
+}
+
+}  // namespace webkit_database