Modularize Compact Language Detector 2 (CLD2) data sources

chrome/browser/translate/scoped_cld_data_harness.h

 // Copyright 2014 The Chromium Authors. All rights reserved.

[Takashi Toyoshima, 2014/06/23 08:50:01]

I feel now just CldDataHarness is more natural to name this class. WDYT? Ditto
on other derived classes.

[Andrew Hayden (chromium.org), 2014/06/23 13:20:35]

I like the word "scoped" because it alerts callers to the fact that this object
has a nontrivial destructor, but I suppose "harness" conveys something similar.
I'll rename, but in a second patchset for cleanliness.

 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CHROME_BROWSER_TRANSLATE_TRANSLATE_BROWSER_TEST_UTILS_H_
-#define CHROME_BROWSER_TRANSLATE_TRANSLATE_BROWSER_TEST_UTILS_H_
+#ifndef CHROME_BROWSER_TRANSLATE_SCOPED_CLD_DATA_HARNESS_H_
+#define CHROME_BROWSER_TRANSLATE_SCOPED_CLD_DATA_HARNESS_H_
 
+#include "base/files/file_path.h"
 #include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
 
 namespace test {
 
 // A utility class that sets up CLD dynamic data upon calling Init() and cleans
 // it up when destroyed.
 // Test data lives under: src/chrome/test/data/cld2_component
 //
 // This class is intended to be instantiated within IN_PROC_BROWSER_TEST_F
 // test fixtures; it uses ASSERT macros for correctness, so that tests will
 // fail gracefully in error conditions. Sample use:
 //
 //   IN_PROC_BROWSER_TEST_F(BrowserTest, PageLanguageDetection) {
-//     test::ScopedCLDDynamicDataHarness dynamic_data_scope;
-//     ASSERT_NO_FATAL_FAILURE(dynamic_data_scope.Init());
+//     scoped_ptr<test::ScopedCldDataHarness> cld_data_scope =
+//       test::CreateScopedCldDataHarness();
+//     ASSERT_NO_FATAL_FAILURE(cld_data_scope.Init());
 //     // ... your code that depends on language detection goes here
 //   }
 //
 // If you have a lot of tests that need language translation features, you can
-// add an instance of the ScopedCLDDynamicDataHarness to your test class'
-// private member variables and add the call to Init() into SetUpOnMainThread.
+// add an instance of the ScopedCldDataHarness to your test class' private
+// member variables and add the call to Init() into SetUpOnMainThread.
 // Sample use:
 //
 //   class MyTestClass : public InProcessBrowserTest {
 //    public:
 //     virtual void SetUpOnMainThread() OVERRIDE {
-//       dynamic_data_scope.Init();
+//       cld_data_scope.Init();
 //       InProcessBrowserTest::SetUpOnMainThread();
 //     }
 //    private:
-//     test::ScopedCLDDynamicDataHarness dynamic_data_scope;
+//     test::ScopedCldDataHarness cld_data_scope;
 //   };
 //
-class ScopedCLDDynamicDataHarness {
+class ScopedCldDataHarness {
  public:
-  // Constructs the object, but does nothing. Call Init() to prepare the
-  // harness, and enclose that call in ASSERT_NO_FATAL_FAILURE(...).
-  ScopedCLDDynamicDataHarness();
-
   // Reverses the work done by the constructor: any files and/or directories
   // that would be created by the constructor are immediately and irrevocably
   // deleted.
   // If dynamic data is not currently available for any reason, this method has
   // no net effect on the runtime.
-  ~ScopedCLDDynamicDataHarness();
+  virtual ~ScopedCldDataHarness() {}
 
   // Call this method, wrapping it in ASSERT_NO_FATAL_FAILURE, to initialize
-  // the harness and trigger test failure of initialization fails.
-  void Init();
+  // the harness and trigger test failure if initialization fails.
+  virtual void Init() = 0;
 
- private:
-  void ClearStandaloneDataFileState();
+ protected:

[Takashi Toyoshima, 2014/06/23 08:50:01]

Can you add some useful comments on following methods?
The first method name implies that it is for a derived class, and implementation
of the second method contains "cld2_component". It is a little confusing at a
glance.

[Andrew Hayden (chromium.org), 2014/06/23 13:20:35]

Done.

+  const base::FilePath::CharType* GetTestDataSourceCrxVersion();
+  void GetTestDataSourceDirectory(base::FilePath* out_path);
+};
 
-  DISALLOW_COPY_AND_ASSIGN(ScopedCLDDynamicDataHarness);
-};
+scoped_ptr<ScopedCldDataHarness> CreateScopedCldDataHarness();
 
 }  // namespace test
 
-#endif  // CHROME_BROWSER_TRANSLATE_TRANSLATE_BROWSER_TEST_UTILS_H_
+#endif  // CHROME_BROWSER_TRANSLATE_SCOPED_CLD_DATA_HARNESS_H_