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      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 #ifndef MEDIA_BASE_CDM_PROMISE_H_
      6 #define MEDIA_BASE_CDM_PROMISE_H_
      7 
      8 #include <string>
      9 
     10 #include "base/basictypes.h"
     11 #include "base/callback.h"
     12 #include "media/base/media_export.h"
     13 #include "media/base/media_keys.h"
     14 
     15 namespace media {
     16 
     17 // Interface for promises being resolved/rejected in response to various
     18 // session actions. These may be called synchronously or asynchronously.
     19 // The promise must be resolved or rejected exactly once. It is expected that
     20 // the caller free the promise once it is resolved/rejected.
     21 //
     22 // This is only the base class, as parameter to resolve() varies.
     23 class MEDIA_EXPORT CdmPromise {
     24  public:
     25   // A superset of media::MediaKeys::Exception for UMA reporting.
     26   enum ResultCodeForUMA {
     27     SUCCESS,
     28     NOT_SUPPORTED_ERROR,
     29     INVALID_STATE_ERROR,
     30     INVALID_ACCESS_ERROR,
     31     QUOTA_EXCEEDED_ERROR,
     32     UNKNOWN_ERROR,
     33     CLIENT_ERROR,
     34     OUTPUT_ERROR,
     35     NUM_RESULT_CODES
     36   };
     37 
     38   enum ResolveParameterType {
     39     VOID_TYPE,
     40     STRING_TYPE,
     41     KEY_IDS_VECTOR_TYPE
     42   };
     43 
     44   typedef base::Callback<void(MediaKeys::Exception exception_code,
     45                               uint32 system_code,
     46                               const std::string& error_message)>
     47       PromiseRejectedCB;
     48 
     49   virtual ~CdmPromise();
     50 
     51   // Used to indicate that the operation failed. |exception_code| must be
     52   // specified. |system_code| is a Key System-specific value for the error
     53   // that occurred, or 0 if there is no associated status code or such status
     54   // codes are not supported by the Key System. |error_message| is optional.
     55   virtual void reject(MediaKeys::Exception exception_code,
     56                       uint32 system_code,
     57                       const std::string& error_message);
     58 
     59   ResolveParameterType GetResolveParameterType() const {
     60     return parameter_type_;
     61   }
     62 
     63  protected:
     64   explicit CdmPromise(ResolveParameterType parameter_type);
     65   CdmPromise(ResolveParameterType parameter_type, PromiseRejectedCB reject_cb);
     66 
     67   // If constructed with a |uma_name| (which must be the name of a
     68   // CdmPromiseResult UMA), CdmPromise will report the promise result (success
     69   // or rejection code).
     70   CdmPromise(ResolveParameterType parameter_type,
     71              PromiseRejectedCB reject_cb,
     72              const std::string& uma_name);
     73 
     74   // Called by all resolve()/reject() methods to report the UMA result if
     75   // applicable, and update |is_pending_|.
     76   void ReportResultToUMA(ResultCodeForUMA result);
     77 
     78   const ResolveParameterType parameter_type_;
     79   PromiseRejectedCB reject_cb_;
     80 
     81   // Keep track of whether the promise hasn't been resolved or rejected yet.
     82   bool is_pending_;
     83 
     84   // UMA name to report result to.
     85   std::string uma_name_;
     86 
     87   DISALLOW_COPY_AND_ASSIGN(CdmPromise);
     88 };
     89 
     90 template <typename T>
     91 class MEDIA_EXPORT CdmPromiseTemplate : public CdmPromise {
     92  public:
     93   CdmPromiseTemplate(base::Callback<void(const T&)> resolve_cb,
     94                      PromiseRejectedCB rejected_cb);
     95   CdmPromiseTemplate(base::Callback<void(const T&)> resolve_cb,
     96                      PromiseRejectedCB rejected_cb,
     97                      const std::string& uma_name);
     98   virtual void resolve(const T& result);
     99 
    100  protected:
    101   // Allow subclasses to completely override the implementation.
    102   CdmPromiseTemplate();
    103 
    104  private:
    105   base::Callback<void(const T&)> resolve_cb_;
    106 
    107   DISALLOW_COPY_AND_ASSIGN(CdmPromiseTemplate);
    108 };
    109 
    110 // Specialization for no parameter to resolve().
    111 template <>
    112 class MEDIA_EXPORT CdmPromiseTemplate<void> : public CdmPromise {
    113  public:
    114   CdmPromiseTemplate(base::Callback<void(void)> resolve_cb,
    115                      PromiseRejectedCB rejected_cb);
    116   CdmPromiseTemplate(base::Callback<void(void)> resolve_cb,
    117                      PromiseRejectedCB rejected_cb,
    118                      const std::string& uma_name);
    119   virtual void resolve();
    120 
    121  protected:
    122   // Allow subclasses to completely override the implementation.
    123   CdmPromiseTemplate();
    124 
    125  private:
    126   base::Callback<void(void)> resolve_cb_;
    127 
    128   DISALLOW_COPY_AND_ASSIGN(CdmPromiseTemplate);
    129 };
    130 
    131 }  // namespace media
    132 
    133 #endif  // MEDIA_BASE_CDM_PROMISE_H_
    134