Cleanup template in CdmPromise

media/base/cdm_promise.cc

 // Copyright 2014 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.
 
 #include "media/base/cdm_promise.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 
 namespace media {
 
+template <typename T>
+struct CdmPromiseTraits {};
+
+template <>
+struct CdmPromiseTraits<void> {
+  static CdmPromise::ResolveParameterType ParameterType() {
+    return CdmPromise::VOID_TYPE;

[xhwang, 2014/09/20 00:34:50]

You can simply do:

static const CdmPromise::ResolveParameterType kType = CdmPromise::VOID_TYPE;

[jrummell, 2014/09/22 19:21:10]

Done.

+  }
+};
+
+template <>
+struct CdmPromiseTraits<std::string> {
+  static CdmPromise::ResolveParameterType ParameterType() {
+    return CdmPromise::STRING_TYPE;
+  }
+};
+
+template <>
+struct CdmPromiseTraits<KeyIdsVector> {
+  static CdmPromise::ResolveParameterType ParameterType() {
+    return CdmPromise::KEY_IDS_VECTOR_TYPE;
+  }
+};
+
 CdmPromise::CdmPromise() : is_pending_(true) {
 }
 
 CdmPromise::CdmPromise(PromiseRejectedCB reject_cb)
     : reject_cb_(reject_cb), is_pending_(true) {
   DCHECK(!reject_cb_.is_null());
 }
 
 CdmPromise::CdmPromise(PromiseRejectedCB reject_cb, const std::string& uma_name)
     : reject_cb_(reject_cb), is_pending_(true), uma_name_(uma_name) {
   DCHECK(!reject_cb_.is_null());
+  DCHECK(!uma_name_.empty());
 }
 
 CdmPromise::~CdmPromise() {
   DCHECK(!is_pending_);
 }
 
 static CdmPromise::ResultCodeForUMA ConvertExceptionToUMAResult(
     MediaKeys::Exception exception_code) {
   switch (exception_code) {
     case MediaKeys::NOT_SUPPORTED_ERROR:
@@ skipping 16 matching lines @@
 }
 
 void CdmPromise::reject(MediaKeys::Exception exception_code,
                         uint32 system_code,
                         const std::string& error_message) {
   DCHECK(is_pending_);
   is_pending_ = false;
   if (!uma_name_.empty()) {
     ResultCodeForUMA result_code = ConvertExceptionToUMAResult(exception_code);
     base::LinearHistogram::FactoryGet(
-        uma_name_, 1, NUM_RESULT_CODES, NUM_RESULT_CODES + 1,
+        uma_name_,
+        1,
+        NUM_RESULT_CODES,
+        NUM_RESULT_CODES + 1,
         base::HistogramBase::kUmaTargetedHistogramFlag)->Add(result_code);
   }
   reject_cb_.Run(exception_code, system_code, error_message);
 }
 
+void CdmPromise::ReportResolution() {
+  DCHECK(is_pending_);
+  is_pending_ = false;
+  if (!uma_name_.empty()) {
+    base::LinearHistogram::FactoryGet(

[ddorwin, 2014/09/19 20:56:46]

As discussed offline, it might make sense to extract ReportResult() so we only
have one location for the UMA call. (This might also allow us to use the macro -
discuss with sandersd.)

[jrummell, 2014/09/22 19:21:10]

Done.

+        uma_name_,
+        1,
+        NUM_RESULT_CODES,
+        NUM_RESULT_CODES + 1,
+        base::HistogramBase::kUmaTargetedHistogramFlag)->Add(SUCCESS);
+  }
+}
+
+template <typename T>
+CdmPromiseTemplate<T>::CdmPromiseTemplate(
+    base::Callback<void(const T&)> resolve_cb,
+    PromiseRejectedCB reject_cb)
+    : CdmPromise(reject_cb), resolve_cb_(resolve_cb) {
+  DCHECK(!resolve_cb_.is_null());
+}
+
+template <typename T>
+CdmPromiseTemplate<T>::CdmPromiseTemplate(
+    base::Callback<void(const T&)> resolve_cb,
+    PromiseRejectedCB reject_cb,
+    const std::string& uma_name)
+    : CdmPromise(reject_cb, uma_name), resolve_cb_(resolve_cb) {
+  DCHECK(!resolve_cb_.is_null());
+}
+
+template <typename T>
+CdmPromiseTemplate<T>::CdmPromiseTemplate() {

[ddorwin, 2014/09/19 20:56:46]

hopefully remove

[jrummell, 2014/09/22 19:21:10]

See comment in .h file.

+}
+
+template <typename T>
+CdmPromiseTemplate<T>::~CdmPromiseTemplate() {
+  DCHECK(!is_pending_);

[ddorwin, 2014/09/19 20:56:46]

The parent's destructor is already doing this. We don't even need to define a
destructor.

[jrummell, 2014/09/22 19:21:10]

Done.

+}
+
+template <typename T>
+void CdmPromiseTemplate<T>::resolve(const T& result) {
+  ReportResolution();
+  resolve_cb_.Run(result);
+}
+
+template <typename T>
+CdmPromise::ResolveParameterType
+CdmPromiseTemplate<T>::GetResolveParameterType() const {
+  return CdmPromiseTraits<T>::ParameterType();
+}
+
 CdmPromiseTemplate<void>::CdmPromiseTemplate(base::Callback<void()> resolve_cb,
                                              PromiseRejectedCB reject_cb)
     : CdmPromise(reject_cb), resolve_cb_(resolve_cb) {
   DCHECK(!resolve_cb_.is_null());
 }
 
 CdmPromiseTemplate<void>::CdmPromiseTemplate(base::Callback<void()> resolve_cb,
                                              PromiseRejectedCB reject_cb,
                                              const std::string& uma_name)
     : CdmPromise(reject_cb, uma_name), resolve_cb_(resolve_cb) {
   DCHECK(!resolve_cb_.is_null());
   DCHECK(!uma_name_.empty());
 }
 
 CdmPromiseTemplate<void>::CdmPromiseTemplate() {
 }
 
 CdmPromiseTemplate<void>::~CdmPromiseTemplate() {
   DCHECK(!is_pending_);
 }
 
 void CdmPromiseTemplate<void>::resolve() {
-  DCHECK(is_pending_);
-  is_pending_ = false;
-  if (!uma_name_.empty()) {
-    base::LinearHistogram::FactoryGet(
-        uma_name_, 1, NUM_RESULT_CODES, NUM_RESULT_CODES + 1,
-        base::HistogramBase::kUmaTargetedHistogramFlag)->Add(SUCCESS);
-  }
+  ReportResolution();
   resolve_cb_.Run();
 }
 
 CdmPromise::ResolveParameterType
 CdmPromiseTemplate<void>::GetResolveParameterType() const {
-  return VOID_TYPE;
+  return CdmPromiseTraits<void>::ParameterType();
 }
 
-CdmPromiseTemplate<std::string>::CdmPromiseTemplate(
-    base::Callback<void(const std::string&)> resolve_cb,
-    PromiseRejectedCB reject_cb)
-    : CdmPromise(reject_cb), resolve_cb_(resolve_cb) {
-  DCHECK(!resolve_cb_.is_null());
-}
-
-CdmPromiseTemplate<std::string>::CdmPromiseTemplate(
-    base::Callback<void(const std::string&)> resolve_cb,
-    PromiseRejectedCB reject_cb,
-    const std::string& uma_name)
-    : CdmPromise(reject_cb, uma_name), resolve_cb_(resolve_cb) {
-  DCHECK(!resolve_cb_.is_null());
-}
-
-CdmPromiseTemplate<std::string>::CdmPromiseTemplate() {
-}
-
-CdmPromiseTemplate<std::string>::~CdmPromiseTemplate() {
-  DCHECK(!is_pending_);
-}
-
-void CdmPromiseTemplate<std::string>::resolve(const std::string& result) {
-  DCHECK(is_pending_);
-  is_pending_ = false;
-  if (!uma_name_.empty()) {
-    base::LinearHistogram::FactoryGet(
-        uma_name_, 1, NUM_RESULT_CODES, NUM_RESULT_CODES + 1,
-        base::HistogramBase::kUmaTargetedHistogramFlag)->Add(SUCCESS);
-  }
-  resolve_cb_.Run(result);
-}
-
-CdmPromise::ResolveParameterType
-CdmPromiseTemplate<std::string>::GetResolveParameterType() const {
-  return STRING_TYPE;
-}
-
-CdmPromiseTemplate<KeyIdsVector>::CdmPromiseTemplate(
-    base::Callback<void(const KeyIdsVector&)> resolve_cb,
-    PromiseRejectedCB reject_cb)
-    : CdmPromise(reject_cb), resolve_cb_(resolve_cb) {
-  DCHECK(!resolve_cb_.is_null());
-}
-
-CdmPromiseTemplate<KeyIdsVector>::CdmPromiseTemplate(
-    base::Callback<void(const KeyIdsVector&)> resolve_cb,
-    PromiseRejectedCB reject_cb,
-    const std::string& uma_name)
-    : CdmPromise(reject_cb, uma_name), resolve_cb_(resolve_cb) {
-  DCHECK(!resolve_cb_.is_null());
-}
-
-CdmPromiseTemplate<KeyIdsVector>::~CdmPromiseTemplate() {
-  DCHECK(!is_pending_);
-}
-
-void CdmPromiseTemplate<KeyIdsVector>::resolve(const KeyIdsVector& result) {
-  DCHECK(is_pending_);
-  is_pending_ = false;
-  if (!uma_name_.empty()) {
-    base::LinearHistogram::FactoryGet(
-        uma_name_, 1, NUM_RESULT_CODES, NUM_RESULT_CODES + 1,
-        base::HistogramBase::kUmaTargetedHistogramFlag)->Add(SUCCESS);
-  }
-  resolve_cb_.Run(result);
-}
-
-CdmPromise::ResolveParameterType
-CdmPromiseTemplate<KeyIdsVector>::GetResolveParameterType() const {
-  return KEY_IDS_VECTOR_TYPE;
-}
+// Explicit template instantiation for the Promises needed.
+template class MEDIA_EXPORT CdmPromiseTemplate<std::string>;
+template class MEDIA_EXPORT CdmPromiseTemplate<KeyIdsVector>;
 
 }  // namespace media