Make FileStream::Seek async and add FileStream::SeekSync for sync operation

net/base/test_completion_callback.h

 // 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.
 
 #ifndef NET_BASE_TEST_COMPLETION_CALLBACK_H_
 #define NET_BASE_TEST_COMPLETION_CALLBACK_H_
 #pragma once
 
 #include "base/compiler_specific.h"
 #include "base/tuple.h"
 #include "net/base/completion_callback.h"
+#include "net/base/net_errors.h"
 
 //-----------------------------------------------------------------------------
 // completion callback helper
 
 // A helper class for completion callbacks, designed to make it easy to run
 // tests involving asynchronous operations.  Just call WaitForResult to wait
 // for the asynchronous operation to complete.
 //
 // NOTE: Since this runs a message loop to wait for the completion callback,
 // there could be other side-effects resulting from WaitForResult.  For this
 // reason, this class is probably not ideal for a general application.
 //
 
-// Base class overridden by custom implementations of TestCompletionCallback.
-class TestCompletionCallbackBase {
+namespace net {
+
+namespace internal {
+
+class TestCompletionCallbackBaseInternal {
  public:
-  void SetResult(int result);
-  int WaitForResult();
-  int GetResult(int result);
   bool have_result() const { return have_result_; }
 
  protected:
-  TestCompletionCallbackBase();
+  TestCompletionCallbackBaseInternal();
+  void DidSetResult();
+  void WaitForResult();
 
-  int result_;
   bool have_result_;
   bool waiting_for_result_;
 
  private:
-  DISALLOW_COPY_AND_ASSIGN(TestCompletionCallbackBase);
+  DISALLOW_COPY_AND_ASSIGN(TestCompletionCallbackBaseInternal);
 };
 
-namespace net {
+template <typename R>
+class TestCompletionCallbackTemplate
+    : public TestCompletionCallbackBaseInternal {
+ public:
+  void SetResult(R result) {
+    result_ = result;
+    DidSetResult();
+  }
+
+  R WaitForResult() {
+    TestCompletionCallbackBaseInternal::WaitForResult();
+    return result_;
+  }
+
+  R GetResult(R result) {
+    if (net::ERR_IO_PENDING != result)
+      return result;
+    return WaitForResult();
+  }
+
+ protected:
+  TestCompletionCallbackTemplate() : result_(R()) {}
+  R result_;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(TestCompletionCallbackTemplate);
+};
+
+}  // namespace internal
+
+// Base class overridden by custom implementations of TestCompletionCallback.
+typedef internal::TestCompletionCallbackTemplate<int>
+    TestCompletionCallbackBase;
+
+typedef internal::TestCompletionCallbackTemplate<int64>
+    TestInt64CompletionCallbackBase;
 
 class TestCompletionCallback : public TestCompletionCallbackBase {
  public:
   TestCompletionCallback();
   ~TestCompletionCallback();
 
   const CompletionCallback& callback() const { return callback_; }
 
  private:
   const CompletionCallback callback_;
 
   DISALLOW_COPY_AND_ASSIGN(TestCompletionCallback);
 };
 
+class TestInt64CompletionCallback : public TestInt64CompletionCallbackBase {
+ public:
+  TestInt64CompletionCallback();
+  ~TestInt64CompletionCallback();
+
+  const Int64CompletionCallback& callback() const { return callback_; }
+
+ private:
+  const Int64CompletionCallback callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestInt64CompletionCallback);
+};
+
 }  // namespace net
 
 #endif  // NET_BASE_TEST_COMPLETION_CALLBACK_H_