media/base/cdm_promise.h

   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   typedef base::Callback<void(MediaKeys::Exception exception_code,
  26                               uint32 system_code,
  27                               const std::string& error_message)>
  28       PromiseRejectedCB;
  29
  30   virtual ~CdmPromise();
  31
  32   // Used to indicate that the operation failed. |exception_code| must be
  33   // specified. |system_code| is a Key System-specific value for the error
  34   // that occurred, or 0 if there is no associated status code or such status
  35   // codes are not supported by the Key System. |error_message| is optional.
  36   virtual void reject(MediaKeys::Exception exception_code,
  37                       uint32 system_code,
  38                       const std::string& error_message);
  39
  40  protected:
  41   CdmPromise();
  42   CdmPromise(PromiseRejectedCB reject_cb);
  43
  44   PromiseRejectedCB reject_cb_;
  45
  46   // Keep track of whether the promise hasn't been resolved or rejected yet.
  47   bool is_pending_;
  48
  49   DISALLOW_COPY_AND_ASSIGN(CdmPromise);
  50 };
  51
  52 template <typename T>
  53 class MEDIA_EXPORT CdmPromiseTemplate : public CdmPromise {
  54  public:
  55   CdmPromiseTemplate(base::Callback<void(const T&)> resolve_cb,
  56                      PromiseRejectedCB rejected_cb);
  57   virtual ~CdmPromiseTemplate();
  58   virtual void resolve(const T& result);
  59
  60  private:
  61   base::Callback<void(const T&)> resolve_cb_;
  62
  63   DISALLOW_COPY_AND_ASSIGN(CdmPromiseTemplate);
  64 };
  65
  66 // Specialization for no parameter to resolve().
  67 template <>
  68 class MEDIA_EXPORT CdmPromiseTemplate<void> : public CdmPromise {
  69  public:
  70   CdmPromiseTemplate(base::Callback<void(void)> resolve_cb,
  71                      PromiseRejectedCB rejected_cb);
  72   virtual ~CdmPromiseTemplate();
  73   virtual void resolve();
  74
  75  protected:
  76   // Allow subclasses to completely override the implementation.
  77   CdmPromiseTemplate();
  78
  79  private:
  80   base::Callback<void(void)> resolve_cb_;
  81
  82   DISALLOW_COPY_AND_ASSIGN(CdmPromiseTemplate);
  83 };
  84
  85 }  // namespace media
  86
  87 #endif  // MEDIA_BASE_CDM_PROMISE_H_