Verify promise type before casting.

media/base/cdm_promise.h

 // 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.
 
 #ifndef MEDIA_BASE_CDM_PROMISE_H_
 #define MEDIA_BASE_CDM_PROMISE_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 17 matching lines @@
     NOT_SUPPORTED_ERROR,
     INVALID_STATE_ERROR,
     INVALID_ACCESS_ERROR,
     QUOTA_EXCEEDED_ERROR,
     UNKNOWN_ERROR,
     CLIENT_ERROR,
     OUTPUT_ERROR,
     NUM_RESULT_CODES
   };
 
+  enum ResolveParameterType {
+    VOID_TYPE,
+    STRING_TYPE,
+    KEY_IDS_VECTOR_TYPE,

[xhwang, 2014/08/27 22:49:26]

nit: no trailing comma to be consistent

[jrummell, 2014/08/27 23:05:13]

Done. The enum above has NUM_RESULT_CODES as always the last enum, where here
the list may grow if we add new templated versions.

+  };
+
   typedef base::Callback<void(MediaKeys::Exception exception_code,
                               uint32 system_code,
                               const std::string& error_message)>
       PromiseRejectedCB;
 
   virtual ~CdmPromise();
 
   // Used to indicate that the operation failed. |exception_code| must be
   // specified. |system_code| is a Key System-specific value for the error
   // that occurred, or 0 if there is no associated status code or such status
   // codes are not supported by the Key System. |error_message| is optional.
   virtual void reject(MediaKeys::Exception exception_code,
                       uint32 system_code,
                       const std::string& error_message);
 
+  virtual ResolveParameterType GetResolveParameterType() const = 0;
+
  protected:
   CdmPromise();
   CdmPromise(PromiseRejectedCB reject_cb);
 
   // If constructed with a |uma_name| (which must be the name of a
   // CdmPromiseResult UMA), CdmPromise will report the promise result (success
   // or rejection code).
   CdmPromise(PromiseRejectedCB reject_cb, const std::string& uma_name);
 
   PromiseRejectedCB reject_cb_;
@@ skipping 10 matching lines @@
 template <typename T>
 class MEDIA_EXPORT CdmPromiseTemplate : public CdmPromise {
  public:
   CdmPromiseTemplate(base::Callback<void(const T&)> resolve_cb,
                      PromiseRejectedCB rejected_cb);
   CdmPromiseTemplate(base::Callback<void(const T&)> resolve_cb,
                      PromiseRejectedCB rejected_cb,
                      const std::string& uma_name);
   virtual ~CdmPromiseTemplate();
   virtual void resolve(const T& result);
+  virtual ResolveParameterType GetResolveParameterType() const OVERRIDE;
 
  protected:
   // Allow subclasses to completely override the implementation.
   // TODO(jrummell): Remove when derived class SessionLoadedPromise
   // (in ppapi_decryptor.cc) is no longer needed.
   CdmPromiseTemplate();
 
  private:
   base::Callback<void(const T&)> resolve_cb_;
 
   DISALLOW_COPY_AND_ASSIGN(CdmPromiseTemplate);
 };
 
 // Specialization for no parameter to resolve().
 template <>
 class MEDIA_EXPORT CdmPromiseTemplate<void> : public CdmPromise {
  public:
   CdmPromiseTemplate(base::Callback<void(void)> resolve_cb,
                      PromiseRejectedCB rejected_cb);
   CdmPromiseTemplate(base::Callback<void(void)> resolve_cb,
                      PromiseRejectedCB rejected_cb,
                      const std::string& uma_name);
   virtual ~CdmPromiseTemplate();
   virtual void resolve();
+  virtual ResolveParameterType GetResolveParameterType() const OVERRIDE;
 
  protected:
   // Allow subclasses to completely override the implementation.
   CdmPromiseTemplate();
 
  private:
   base::Callback<void(void)> resolve_cb_;
 
   DISALLOW_COPY_AND_ASSIGN(CdmPromiseTemplate);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_CDM_PROMISE_H_