Migrate the IndexedDB backend from Blink to Chromium

content/browser/indexed_db/indexed_db_transaction.cc

+// Copyright (c) 2013 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 "content/browser/indexed_db/indexed_db_transaction.h"
+
+#include "base/logging.h"
+#include "base/utf_string_conversions.h"
+#include "content/browser/indexed_db/indexed_db_backing_store.h"
+#include "content/browser/indexed_db/indexed_db_cursor_impl.h"
+#include "content/browser/indexed_db/indexed_db_database_callbacks_wrapper.h"
+#include "content/browser/indexed_db/indexed_db_database_impl.h"
+#include "content/browser/indexed_db/indexed_db_tracing.h"
+#include "content/browser/indexed_db/indexed_db_transaction_coordinator.h"
+#include "third_party/WebKit/Source/Platform/chromium/public/WebIDBDatabaseException.h"
+
+namespace content {
+
+IndexedDBTransaction::TaskQueue::TaskQueue() {}
+IndexedDBTransaction::TaskQueue::~TaskQueue() { clear(); }
+
+void IndexedDBTransaction::TaskQueue::clear() {
+  while (!queue_.empty())
+    scoped_ptr<Operation> task(pop());
+}
+
+scoped_ptr<IndexedDBTransaction::Operation>
+IndexedDBTransaction::TaskQueue::pop() {
+  DCHECK(!queue_.empty());
+  scoped_ptr<Operation> task(queue_.front());
+  queue_.pop();
+  return task.Pass();
+}
+
+IndexedDBTransaction::TaskStack::TaskStack() {}
+IndexedDBTransaction::TaskStack::~TaskStack() { clear(); }
+
+void IndexedDBTransaction::TaskStack::clear() {
+  while (!stack_.empty())
+    scoped_ptr<Operation> task(pop());
+}
+
+scoped_ptr<IndexedDBTransaction::Operation>
+IndexedDBTransaction::TaskStack::pop() {
+  DCHECK(!stack_.empty());
+  scoped_ptr<Operation> task(stack_.top());
+  stack_.pop();
+  return task.Pass();
+}
+
+scoped_refptr<IndexedDBTransaction> IndexedDBTransaction::Create(
+    int64_t id,
+    scoped_refptr<IndexedDBDatabaseCallbacksWrapper> callbacks,
+    const std::vector<int64_t>& object_store_ids,
+    IndexedDB::TransactionMode mode,
+    IndexedDBDatabaseImpl* database) {
+  std::set<int64_t> object_store_hash_set;
+  for (size_t i = 0; i < object_store_ids.size(); ++i)
+    object_store_hash_set.insert(object_store_ids[i]);
+
+  return make_scoped_refptr(new IndexedDBTransaction(
+      id, callbacks, object_store_hash_set, mode, database));
+}
+
+IndexedDBTransaction::IndexedDBTransaction(
+    int64_t id,
+    scoped_refptr<IndexedDBDatabaseCallbacksWrapper> callbacks,
+    const std::set<int64_t>& object_store_ids,
+    IndexedDB::TransactionMode mode,
+    IndexedDBDatabaseImpl* database)
+    : id_(id),
+      object_store_ids_(object_store_ids),
+      mode_(mode),
+      state_(Unused),
+      commit_pending_(false),
+      callbacks_(callbacks),
+      database_(database),
+      transaction_(database->BackingStore().get()),
+      pending_preemptive_events_(0) {
+  database_->transaction_coordinator().DidCreateTransaction(this);
+}
+
+IndexedDBTransaction::~IndexedDBTransaction() {
+  // It shouldn't be possible for this object to get deleted until it's either
+  // complete or aborted.
+  DCHECK(state_ == Finished);
+  DCHECK(preemptive_task_queue_.empty());
+  DCHECK(task_queue_.empty());
+  DCHECK(abort_task_stack_.empty());
+}
+
+void IndexedDBTransaction::ScheduleTask(IndexedDBDatabase::TaskType type,
+                                        Operation* task,
+                                        Operation* abort_task) {
+  if (state_ == Finished)
+    return;
+
+  if (type == IndexedDBDatabase::NormalTask)
+    task_queue_.push(task);
+  else
+    preemptive_task_queue_.push(task);
+
+  if (abort_task)
+    abort_task_stack_.push(abort_task);
+
+  if (state_ == Unused)
+    Start();
+  else if (state_ == Running && !task_timer_.IsRunning())
+    task_timer_.Start(FROM_HERE,
+                      base::TimeDelta::FromSeconds(0),
+                      this,
+                      &IndexedDBTransaction::TaskTimerFired);
+}
+
+void IndexedDBTransaction::Abort() {
+  Abort(IndexedDBDatabaseError::Create(
+      WebKit::WebIDBDatabaseExceptionUnknownError,
+      ASCIIToUTF16("Internal error (unknown cause)")));
+}
+
+void IndexedDBTransaction::Abort(scoped_refptr<IndexedDBDatabaseError> error) {
+  IDB_TRACE("IndexedDBTransaction::abort");
+  if (state_ == Finished)
+    return;
+
+  bool was_running = state_ == Running;
+
+  // The last reference to this object may be released while performing the
+  // abort steps below. We therefore take a self reference to keep ourselves
+  // alive while executing this method.
+  scoped_refptr<IndexedDBTransaction> protect(this);
+
+  state_ = Finished;
+  task_timer_.Stop();
+
+  if (was_running)
+    transaction_.Rollback();
+
+  // Run the abort tasks, if any.
+  while (!abort_task_stack_.empty()) {
+    scoped_ptr<Operation> task(abort_task_stack_.pop());
+    task->Perform(0);
+  }
+  preemptive_task_queue_.clear();
+  task_queue_.clear();
+
+  // Backing store resources (held via cursors) must be released
+  // before script callbacks are fired, as the script callbacks may
+  // release references and allow the backing store itself to be
+  // released, and order is critical.
+  CloseOpenCursors();
+  transaction_.Reset();
+
+  // Transactions must also be marked as completed before the
+  // front-end is notified, as the transaction completion unblocks
+  // operations like closing connections.
+  database_->transaction_coordinator().DidFinishTransaction(this);
+  DCHECK(!database_->transaction_coordinator().IsActive(this));
+  database_->TransactionFinished(this);
+
+  if (callbacks_)
+    callbacks_->OnAbort(id_, error);
+
+  database_->TransactionFinishedAndAbortFired(this);
+
+  database_ = NULL;
+}
+
+bool IndexedDBTransaction::IsTaskQueueEmpty() const {
+  return preemptive_task_queue_.empty() && task_queue_.empty();
+}
+
+bool IndexedDBTransaction::HasPendingTasks() const {
+  return pending_preemptive_events_ || !IsTaskQueueEmpty();
+}
+
+void IndexedDBTransaction::RegisterOpenCursor(IndexedDBCursorImpl* cursor) {
+  open_cursors_.insert(cursor);
+}
+
+void IndexedDBTransaction::UnregisterOpenCursor(IndexedDBCursorImpl* cursor) {
+  open_cursors_.erase(cursor);
+}
+
+void IndexedDBTransaction::Run() {
+  // TransactionCoordinator has started this transaction. Schedule a timer
+  // to process the first task.
+  DCHECK(state_ == StartPending || state_ == Running);
+  DCHECK(!task_timer_.IsRunning());
+
+  task_timer_.Start(FROM_HERE,
+                    base::TimeDelta::FromSeconds(0),
+                    this,
+                    &IndexedDBTransaction::TaskTimerFired);
+}
+
+void IndexedDBTransaction::Start() {
+  DCHECK(state_ == Unused);
+
+  state_ = StartPending;
+  database_->transaction_coordinator().DidStartTransaction(this);
+  database_->TransactionStarted(this);
+}
+
+void IndexedDBTransaction::Commit() {
+  IDB_TRACE("IndexedDBTransaction::commit");
+
+  // In multiprocess ports, front-end may have requested a commit but
+  // an abort has already been initiated asynchronously by the
+  // back-end.
+  if (state_ == Finished)
+    return;
+
+  DCHECK(state_ == Unused || state_ == Running);
+  commit_pending_ = true;
+
+  // Front-end has requested a commit, but there may be tasks like
+  // create_index which are considered synchronous by the front-end
+  // but are processed asynchronously.
+  if (HasPendingTasks())
+    return;
+
+  // The last reference to this object may be released while performing the
+  // commit steps below. We therefore take a self reference to keep ourselves
+  // alive while executing this method.
+  scoped_refptr<IndexedDBTransaction> protect(this);
+
+  // TODO(jsbell): Run abort tasks if commit fails? http://crbug.com/241843
+  abort_task_stack_.clear();
+
+  bool unused = state_ == Unused;
+  state_ = Finished;
+
+  bool committed = unused || transaction_.Commit();
+
+  // Backing store resources (held via cursors) must be released
+  // before script callbacks are fired, as the script callbacks may
+  // release references and allow the backing store itself to be
+  // released, and order is critical.
+  CloseOpenCursors();
+  transaction_.Reset();
+
+  // Transactions must also be marked as completed before the
+  // front-end is notified, as the transaction completion unblocks
+  // operations like closing connections.
+  if (!unused)
+    database_->transaction_coordinator().DidFinishTransaction(this);
+  database_->TransactionFinished(this);
+
+  if (committed) {
+    callbacks_->OnComplete(id_);
+    database_->TransactionFinishedAndCompleteFired(this);
+  } else {
+    callbacks_->OnAbort(
+        id_,
+        IndexedDBDatabaseError::Create(
+            WebKit::WebIDBDatabaseExceptionUnknownError,
+            ASCIIToUTF16("Internal error committing transaction.")));
+    database_->TransactionFinishedAndAbortFired(this);
+  }
+
+  database_ = NULL;
+}
+
+void IndexedDBTransaction::TaskTimerFired() {
+  IDB_TRACE("IndexedDBTransaction::task_timer_fired");
+  DCHECK(!IsTaskQueueEmpty());
+
+  if (state_ == StartPending) {
+    transaction_.begin();
+    state_ = Running;
+  }
+
+  // The last reference to this object may be released while performing the
+  // tasks. Take take a self reference to keep this object alive so that
+  // the loop termination conditions can be checked.
+  scoped_refptr<IndexedDBTransaction> protect(this);
+
+  TaskQueue* task_queue =
+      pending_preemptive_events_ ? &preemptive_task_queue_ : &task_queue_;
+  while (!task_queue->empty() && state_ != Finished) {
+    DCHECK(state_ == Running);
+    scoped_ptr<Operation> task(task_queue->pop());
+    task->Perform(this);
+
+    // Event itself may change which queue should be processed next.
+    task_queue =
+        pending_preemptive_events_ ? &preemptive_task_queue_ : &task_queue_;
+  }
+
+  // If there are no pending tasks, we haven't already committed/aborted,
+  // and the front-end requested a commit, it is now safe to do so.
+  if (!HasPendingTasks() && state_ != Finished && commit_pending_)
+    Commit();
+}
+
+void IndexedDBTransaction::CloseOpenCursors() {
+  for (std::set<IndexedDBCursorImpl*>::iterator i = open_cursors_.begin();
+       i != open_cursors_.end();
+       ++i)
+    (*i)->Close();
+  open_cursors_.clear();
+}
+
+}  // namespace content