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1 // Copyright (c) 2011 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 PPAPI_CPP_CORE_H_
6 #define PPAPI_CPP_CORE_H_
7 
8 #include "ppapi/c/ppb_core.h"
9 
10 /// @file
11 /// This file defines APIs related to memory management, time, and threads.
12 
13 namespace pp {
14 
15 class CompletionCallback;
16 class Module;
17 
18 /// APIs related to memory management, time, and threads.
19 class Core {
20  public:
21   // Note that we explicitly don't expose Resource& versions of this function
22   // since Resource will normally manage the refcount properly. These should
23   // be called only when doing manual management on raw PP_Resource handles,
24   // which should be fairly rare.
25 
26   /// AddRefResource() increments the reference count for the provided
27   /// <code>resource</code>.
28   ///
29   /// @param[in] resource A <code>PP_Resource</code> corresponding to a
30   /// resource.
AddRefResource(PP_Resource resource)31   void AddRefResource(PP_Resource resource) {
32     interface_->AddRefResource(resource);
33   }
34 
35   /// ReleaseResource() decrements the reference count for the provided
36   /// <code>resource</code>. The resource will be deallocated if the
37   /// reference count reaches zero.
38   ///
39   /// @param[in] resource A <code>PP_Resource</code> corresponding to a
40   /// resource.
ReleaseResource(PP_Resource resource)41   void ReleaseResource(PP_Resource resource) {
42     interface_->ReleaseResource(resource);
43   }
44 
45   /// GetTime() returns the "wall clock time" according to the
46   /// browser.
47   ///
48   /// @return A <code>PP_Time</code> containing the "wall clock time" according
49   /// to the browser.
GetTime()50   PP_Time GetTime() {
51     return interface_->GetTime();
52   }
53 
54   /// GetTimeTicks() returns the "tick time" according to the browser.
55   /// This clock is used by the browser when passing some event times to the
56   /// module (for example, using the
57   /// <code>PP_InputEvent::time_stamp_seconds</code> field). It is not
58   /// correlated to any actual wall clock time (like GetTime()). Because
59   /// of this, it will not change if the user changes their computer clock.
60   ///
61   /// @return A <code>PP_TimeTicks</code> containing the "tick time" according
62   /// to the browser.
GetTimeTicks()63   PP_TimeTicks GetTimeTicks() {
64     return interface_->GetTimeTicks();
65   }
66 
67   /// CallOnMainThread() schedules work to be executed on the main pepper
68   /// thread after the specified delay. The delay may be 0 to specify a call
69   /// back as soon as possible.
70   ///
71   /// The |result| parameter will just be passed as the second argument to the
72   /// callback. Many applications won't need this, but it allows a module to
73   /// emulate calls of some callbacks which do use this value.
74   ///
75   /// <strong>Note:</strong> CallOnMainThread(), even when used from the main
76   /// thread with a delay of 0 milliseconds, will never directly invoke the
77   /// callback.  Even in this case, the callback will be scheduled
78   /// asynchronously.
79   ///
80   /// <strong>Note:</strong> If the browser is shutting down or if the module
81   /// has no instances, then the callback function may not be called.
82   ///
83   /// @param[in] delay_in_milliseconds An int32_t delay in milliseconds.
84   /// @param[in] callback A <code>CompletionCallback</code> callback function
85   /// that the browser will call after the specified delay.
86   /// @param[in] result An int32_t that the browser will pass to the given
87   /// <code>CompletionCallback</code>.
88   void CallOnMainThread(int32_t delay_in_milliseconds,
89                         const CompletionCallback& callback,
90                         int32_t result = 0);
91 
92 
93   /// IsMainThread() returns true if the current thread is the main pepper
94   /// thread.
95   ///
96   /// This function is useful for implementing sanity checks, and deciding if
97   /// dispatching using CallOnMainThread() is required.
98   ///
99   /// @return true if the current thread is the main pepper thread, otherwise
100   /// false.
101   bool IsMainThread();
102 
103  private:
104   // Allow Module to construct.
105   friend class Module;
106 
107   // Only module should make this class so this constructor is private.
Core(const PPB_Core * inter)108   Core(const PPB_Core* inter) : interface_(inter) {}
109 
110   // Copy and assignment are disallowed.
111   Core(const Core& other);
112   Core& operator=(const Core& other);
113 
114   const PPB_Core* interface_;
115 };
116 
117 }  // namespace pp
118 
119 #endif  // PPAPI_CPP_CORE_H_
120