Report text output and exit code for command-line operations.

chrome/browser/operation_output.h

Index: chrome/browser/operation_output.h
diff --git a/chrome/browser/operation_output.h b/chrome/browser/operation_output.h
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+++ b/chrome/browser/operation_output.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.
+//
+// See apps/app_host/operation_launcher.h for more information about the
+// definition of an operation.
+
+#ifndef CHROME_BROWSER_OPERATION_OUTPUT_H_
+#define CHROME_BROWSER_OPERATION_OUTPUT_H_
+
+#include "base/memory/scoped_ptr.h"
+
+class CommandLine;
+
+// Defines an interface for reporting the output of an operation to its client.
+// While the operation is ongoing, it may produce output (via |Write()|).
+// Terminate the operation by passing it to |Complete()| along with an exit
+// code.
+class OperationOutput {
+ public:
+  // Instantiates an OperationOutput channel based on the provided command-line.
+  // The required arguments are platform dependent.
+  // This always returns NULL if not on Windows.
+  static scoped_ptr<OperationOutput> Create(const CommandLine& command_line);
+
+  virtual ~OperationOutput() {}
+
+  // Signals the completion of the operation with the specified exit code.
+  // Returns true if the exit code is successfully written.
+  static bool Complete(scoped_ptr<OperationOutput> operation_output,
+                       unsigned int exit_code);
+
+  // Sends operation output to the client. Returns true if the output is
+  // successfully written.
+  virtual bool Write(const char* data, unsigned int length) = 0;
+
+ private:
+  // Sends operation exit code to the client. Returns true if the exit code is
+  // successfully written.
+  virtual bool SetExitCode(unsigned int exit_code) = 0;
+};
+
+#endif  // CHROME_BROWSER_OPERATION_OUTPUT_H_