chrome/browser/translate/cld_data_harness_factory.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/browser/translate/cld_data_harness_factory.h"
   6
   7 #include "base/lazy_instance.h"
   8 #include "chrome/browser/translate/component_cld_data_harness.h"
   9 #include "chrome/browser/translate/standalone_cld_data_harness.h"
  10 #include "components/translate/content/browser/browser_cld_utils.h"
  11 #include "components/translate/content/common/cld_data_source.h"
  12
  13 namespace {
  14
  15 // This is the global instance managed by Get/Set
  16 test::CldDataHarnessFactory* g_instance = NULL;
  17
  18 // The following three instances are used to "cheat" in Create(). Each of them
  19 // is just an instance of this class, but because they are singletons they can
  20 // be compared using "this" to pick different behaviors in Create() at runtime.
  21 // This avoids the need to explicitly define boilerplate classes with no
  22 // significant value.
  23 //
  24 // Embedders can of course specify a different implementation of this class
  25 // using Set(CldDataHarnessFactory*), in which case Create() will have whatever
  26 // custom behavior is desired.
  27 base::LazyInstance<test::CldDataHarnessFactory>::Leaky g_wrapped_component =
  28     LAZY_INSTANCE_INITIALIZER;
  29 base::LazyInstance<test::CldDataHarnessFactory>::Leaky g_wrapped_standalone =
  30     LAZY_INSTANCE_INITIALIZER;
  31 base::LazyInstance<test::CldDataHarnessFactory>::Leaky g_wrapped_static =
  32     LAZY_INSTANCE_INITIALIZER;
  33
  34 }  // namespace
  35
  36 namespace test {
  37
  38 scoped_ptr<CldDataHarness> CldDataHarnessFactory::CreateCldDataHarness() {
  39   // Cheat: Since the three "canned" implementations are all well-known, just
  40   // check to see if "this" points to one of the singletons and then return
  41   // the right answer. Embedder-provided CldDataHarnessFactory implementations
  42   // will of course not have this behavior.
  43   if (this == GetStaticDataHarnessFactory()) {
  44     return CldDataHarness::CreateStaticDataHarness();
  45   }
  46   if (this == GetStandaloneDataHarnessFactory()) {
  47     return CldDataHarness::CreateStandaloneDataHarness();
  48   }
  49   if (this == GetComponentDataHarnessFactory()) {
  50     return CldDataHarness::CreateComponentDataHarness();
  51   }
  52
  53   // Embedder did something wrong, failed to override this method.
  54   NOTREACHED() << "Subclass failed to override CreateCldDataHarness()";
  55   return CldDataHarness::CreateStaticDataHarness();
  56 }
  57
  58 CldDataHarnessFactory* CldDataHarnessFactory::Get() {
  59   // First honor any factory set by the embedder.
  60   if (g_instance != NULL) return g_instance;
  61
  62   // Fall back to defaults: try to find a compatible harness for the currently-
  63   // configured CldDataSource.
  64   translate::BrowserCldUtils::ConfigureDefaultDataProvider();
  65   if (translate::CldDataSource::IsUsingStaticDataSource()) {
  66     return GetStaticDataHarnessFactory();
  67   }
  68   if (translate::CldDataSource::IsUsingComponentDataSource()) {
  69     return GetComponentDataHarnessFactory();
  70   }
  71   if (translate::CldDataSource::IsUsingStandaloneDataSource()) {
  72     return GetStandaloneDataHarnessFactory();
  73   }
  74
  75   // The CldDataSource must have been set by an embedder, but the embedder has
  76   // not configured a corresponding CldDataHarnessFactory. This is an error; the
  77   // embedder must specify a harness that works with the corresponding
  78   // CldDataSource. Crash for debug builds and return a no-op harness for
  79   // everything else.
  80   NOTREACHED() << "No CLD data harness factory was configured!";
  81   return GetStaticDataHarnessFactory();
  82 }
  83
  84 // static
  85 void CldDataHarnessFactory::Set(CldDataHarnessFactory* instance) {
  86   g_instance = instance;
  87 }
  88
  89 // static
  90 CldDataHarnessFactory*
  91 CldDataHarnessFactory::GetStaticDataHarnessFactory() {
  92   return &g_wrapped_static.Get();
  93 }
  94
  95 // static
  96 CldDataHarnessFactory*
  97 CldDataHarnessFactory::GetStandaloneDataHarnessFactory() {
  98   return &g_wrapped_standalone.Get();
  99 }
 100
 101 // static
 102 CldDataHarnessFactory*
 103 CldDataHarnessFactory::GetComponentDataHarnessFactory() {
 104   return &g_wrapped_component.Get();
 105 }
 106
 107 }  // namespace test