Migrate the IndexedDB backend from Blink to Chromium

content/browser/indexed_db/indexed_db_transaction.h

Index: content/browser/indexed_db/indexed_db_transaction.h
diff --git a/content/browser/indexed_db/indexed_db_transaction.h b/content/browser/indexed_db/indexed_db_transaction.h
new file mode 100644
index 0000000000000000000000000000000000000000..0a080c54bc743f1ceb8cff27a5a935a70122e162
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+++ b/content/browser/indexed_db/indexed_db_transaction.h
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+// 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.
+
+#ifndef CONTENT_BROWSER_INDEXED_DB_INDEXED_DB_TRANSACTION_H_
+#define CONTENT_BROWSER_INDEXED_DB_INDEXED_DB_TRANSACTION_H_
+
+#include <queue>
+#include <set>
+#include <stack>
+
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/timer.h"
+#include "content/browser/indexed_db/indexed_db_backing_store.h"
+#include "content/browser/indexed_db/indexed_db_database.h"
+#include "content/browser/indexed_db/indexed_db_database_error.h"
+
+namespace content {
+
+class IndexedDBDatabaseImpl;
+class IndexedDBCursorImpl;
+class IndexedDBDatabaseCallbacksWrapper;
+
+class IndexedDBTransaction : public base::RefCounted<IndexedDBTransaction> {
+ public:
+  static scoped_refptr<IndexedDBTransaction> Create(
+      int64_t transaction_id,
+      scoped_refptr<IndexedDBDatabaseCallbacksWrapper>,
+      const std::vector<int64_t>&,
+      IndexedDB::TransactionMode,
+      IndexedDBDatabaseImpl*);
+
+  virtual void Abort();
+  void Commit();
+
+  class Operation {
+   public:
+    Operation() {}
+    virtual ~Operation() {}
+    virtual void Perform(IndexedDBTransaction*) = 0;
+  };
+
+  void Abort(scoped_refptr<IndexedDBDatabaseError>);
+  void Run();
+  IndexedDB::TransactionMode mode() const { return mode_; }
+  const std::set<int64_t>& scope() const { return object_store_ids_; }
+  void ScheduleTask(Operation* task, Operation* abort_task = NULL) {
+    ScheduleTask(IndexedDBDatabase::NormalTask, task, abort_task);
+  }
+  void ScheduleTask(IndexedDBDatabase::TaskType,
+                    Operation* task,
+                    Operation* abort_task = NULL);
+  void RegisterOpenCursor(IndexedDBCursorImpl*);
+  void UnregisterOpenCursor(IndexedDBCursorImpl*);
+  void AddPreemptiveEvent() { pending_preemptive_events_++; }
+  void DidCompletePreemptiveEvent() {
+    pending_preemptive_events_--;
+    DCHECK(pending_preemptive_events_ >= 0);
+  }
+  IndexedDBBackingStore::Transaction* BackingStoreTransaction() {
+    return &transaction_;
+  }
+  int64_t id() const { return id_; }
+
+  IndexedDBDatabaseImpl* database() const { return database_.get(); }
+  IndexedDBDatabaseCallbacksWrapper* connection() const {
+    return callbacks_.get();
+  }
+
+ protected:
+  virtual ~IndexedDBTransaction();
+  friend class base::RefCounted<IndexedDBTransaction>;
+
+ private:
+  IndexedDBTransaction(int64_t id,
+                       scoped_refptr<IndexedDBDatabaseCallbacksWrapper>,
+                       const std::set<int64_t>& object_store_ids,
+                       IndexedDB::TransactionMode,
+                       IndexedDBDatabaseImpl*);
+
+  enum State {
+    Unused,        // Created, but no tasks yet.
+    StartPending,  // Enqueued tasks, but backing store transaction not yet
+                   // started.
+    Running,       // Backing store transaction started but not yet finished.
+    Finished,      // Either aborted or committed.
+  };
+
+  void Start();
+
+  bool IsTaskQueueEmpty() const;
+  bool HasPendingTasks() const;
+
+  void TaskTimerFired();
+  void CloseOpenCursors();
+
+  const int64_t id_;
+  const std::set<int64_t> object_store_ids_;
+  const IndexedDB::TransactionMode mode_;
+
+  State state_;
+  bool commit_pending_;
+  scoped_refptr<IndexedDBDatabaseCallbacksWrapper> callbacks_;
+  scoped_refptr<IndexedDBDatabaseImpl> database_;
+
+  class TaskQueue {
+   public:
+    TaskQueue();
+    ~TaskQueue();
+    bool empty() const { return queue_.empty(); }
+    void push(Operation* task) { queue_.push(task); }
+    scoped_ptr<Operation> pop();
+    void clear();
+
+   private:
+    std::queue<Operation*> queue_;
+  };
+
+  class TaskStack {
+   public:
+    TaskStack();
+    ~TaskStack();
+    bool empty() const { return stack_.empty(); }
+    void push(Operation* task) { stack_.push(task); }
+    scoped_ptr<Operation> pop();
+    void clear();
+
+   private:
+    std::stack<Operation*> stack_;
+  };
+
+  TaskQueue task_queue_;
+  TaskQueue preemptive_task_queue_;
+  TaskStack abort_task_stack_;
+
+  IndexedDBBackingStore::Transaction transaction_;
+
+  base::OneShotTimer<IndexedDBTransaction> task_timer_;
+  int pending_preemptive_events_;
+
+  std::set<IndexedDBCursorImpl*> open_cursors_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_INDEXED_DB_INDEXED_DB_TRANSACTION_H_