Test file errors in downloads.

content/test/test_file_error_injector.h

Index: content/test/test_file_error_injector.h
diff --git a/content/test/test_file_error_injector.h b/content/test/test_file_error_injector.h
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+// Copyright (c) 2011 The Chromium Authors. All rights reserved.

[cbentzel, 2012/03/01 15:44:20]

2012

[ahendrickson, 2012/03/01 20:19:31]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_TEST_TEST_FILE_ERROR_INJECTOR_H_
+#define CONTENT_TEST_TEST_FILE_ERROR_INJECTOR_H_
+#pragma once
+
+#include <string>
+
+#include "base/memory/ref_counted.h"
+#include "content/public/browser/download_id.h"
+#include "net/base/net_errors.h"
+
+class GURL;
+
+namespace content {
+
+// Test helper for injecting errors into download file operations.
+// All errors for a download must be injected before it starts.
+// This class needs to be |RefCountedThreadSafe| because the implementation
+// is referenced by other classes that live past the time when the user is
+// nominally done with it.  These classes are internal to content/.
+//
+// NOTE: No more than one download with the same URL can be in progress at
+// the same time.  You can have multiple simultaneous downloads as long as the
+// URLs are different.
+class TestFileErrorInjector
+    : public base::RefCountedThreadSafe<TestFileErrorInjector> {
+ public:
+  enum FileOperationCode {
+    FILE_OPERATION_INITIALIZE,
+    FILE_OPERATION_WRITE,
+    FILE_OPERATION_RENAME
+  };
+
+  // Structure that encapsulates the information needed to inject a file error.
+  struct FileErrorInfo {
+    std::string url;  // Full URL of the download.  Identifies the download.
+    FileOperationCode code;  // Operation to affect.
+    int operation_instance;  // 0-based count of operation calls.
+    net::Error net_error;  // Error to inject.
+  };
+
+  TestFileErrorInjector() {}
+
+  // Creates an instance.

[cbentzel, 2012/03/01 15:44:20]

Should this be called Create instead?

[ahendrickson, 2012/03/01 20:19:31]

Randy pointed out that if this has singleton semantics (which I think it must),
the function should be called Get().

[Randy Smith (Not in Mondays), 2012/03/01 20:28:25]

It was shifted in response to a comment of mine.  It looked to me that it didn't
make sense for TestFileErrorInjector not to have singleton semantics (if you
have two, I think things get somewhat wonky), so I suggested singleton
semantics, and the shift to Get was part of that.  The comment should be
updated, though.

+  static scoped_refptr<TestFileErrorInjector> Get();
+
+  // Adds an error.
+  // Must be called before |InjectErrors()| for a particular download file.
+  // Only one error per file will be used.
+  virtual bool AddError(const FileErrorInfo& error_info) = 0;
+
+  // Clears all errors.
+  // Doesn't affect files already created.
+  virtual void ClearErrors() = 0;
+
+  // Injects the errors.
+  // The download system must already be initialized before calling this.
+  virtual bool InjectErrors() = 0;
+
+  // Get information about the DownloadFiles created.

[Randy Smith (Not in Mondays), 2012/03/01 20:28:25]

Could you add some comments for these interfaces?  What's the difference between
CurrentFileCount() and TotalFileCount()?  What does HadFile() mean?  If you do
two different downloads with the same URL serially, which does GetId() return? 
What does ClearFoundFiles() do/which of the other interfaces does it affect, and
which doesn't it affect?

[Randy Smith (Not in Mondays), 2012/03/06 23:05:19]

Ping?

[ahendrickson, 2012/03/08 22:00:08]

Added comments.

[ahendrickson, 2012/03/08 22:00:08]

Sorry, this was at the bottom of my list of CLs.

+  virtual size_t CurrentFileCount() const = 0;
+  virtual size_t TotalFileCount() const = 0;
+  virtual bool HadFile(const GURL& url) const = 0;
+  virtual const content::DownloadId GetId(const GURL& url) const = 0;
+  virtual void ClearFoundFiles() = 0;
+
+  static std::string DebugString(FileOperationCode code);

[cbentzel, 2012/03/01 15:44:20]

This doesn't need to be part of the public interface.

[ahendrickson, 2012/03/01 20:19:31]

Then how do I use it in the browser test?

[cbentzel, 2012/03/01 22:32:00]

Ah OK. Then it does. Not sure if it should, but not going to fight. 

+
+ protected:
+  virtual ~TestFileErrorInjector() {}
+
+ private:
+  friend class base::RefCountedThreadSafe<TestFileErrorInjector>;
+
+  DISALLOW_COPY_AND_ASSIGN(TestFileErrorInjector);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_TEST_TEST_FILE_ERROR_INJECTOR_H_