cc/output/begin_frame_args.h

   1 // Copyright 2013 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 CC_OUTPUT_BEGIN_FRAME_ARGS_H_
   6 #define CC_OUTPUT_BEGIN_FRAME_ARGS_H_
   7
   8 #include "base/location.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "base/time/time.h"
  11 #include "base/values.h"
  12 #include "cc/base/cc_export.h"
  13
  14 namespace base {
  15 namespace trace_event {
  16 class ConvertableToTraceFormat;
  17 class TracedValue;
  18 }
  19
  20 // TODO(ssid): remove these aliases after the tracing clients are moved to the
  21 // new trace_event namespace. See crbug.com/451032. ETA: March 2015
  22 namespace debug {
  23 using ::base::trace_event::ConvertableToTraceFormat;
  24 using ::base::trace_event::TracedValue;
  25 }
  26 }  // namespace base
  27
  28 /**
  29  * In debug builds we trace the creation origin of BeginFrameArgs objects. We
  30  * reuse the tracked_objects::Location system to do that.
  31  *
  32  * However, in release builds we don't want this as it doubles the size of the
  33  * BeginFrameArgs object. As well it adds a number of largish strings to the
  34  * binary. Despite the argument being unused, most compilers are unable to
  35  * optimise it away even when unused. Instead we use the BEGINFRAME_FROM_HERE
  36  * macro to prevent the data even getting referenced.
  37  */
  38 #ifdef NDEBUG
  39 #define BEGINFRAME_FROM_HERE nullptr
  40 #else
  41 #define BEGINFRAME_FROM_HERE FROM_HERE
  42 #endif
  43
  44 namespace cc {
  45
  46 struct CC_EXPORT BeginFrameArgs {
  47   enum BeginFrameArgsType {
  48     INVALID,
  49     NORMAL,
  50     SYNCHRONOUS,
  51     MISSED,
  52     // Not a real type, but used by the IPC system. Should always remain the
  53     // *last* value in this enum.
  54     BEGIN_FRAME_ARGS_TYPE_MAX,
  55   };
  56   static const char* TypeToString(BeginFrameArgsType type);
  57
  58   // Creates an invalid set of values.
  59   BeginFrameArgs();
  60
  61 #ifdef NDEBUG
  62   typedef const void* CreationLocation;
  63 #else
  64   typedef const tracked_objects::Location& CreationLocation;
  65   tracked_objects::Location created_from;
  66 #endif
  67
  68   // You should be able to find all instances where a BeginFrame has been
  69   // created by searching for "BeginFrameArgs::Create".
  70   // The location argument should **always** be BEGINFRAME_FROM_HERE macro.
  71   static BeginFrameArgs Create(CreationLocation location,
  72                                base::TimeTicks frame_time,
  73                                base::TimeTicks deadline,
  74                                base::TimeDelta interval,
  75                                BeginFrameArgsType type);
  76
  77   // This is the default delta that will be used to adjust the deadline when
  78   // proper draw-time estimations are not yet available.
  79   static base::TimeDelta DefaultEstimatedParentDrawTime();
  80
  81   // This is the default interval to use to avoid sprinkling the code with
  82   // magic numbers.
  83   static base::TimeDelta DefaultInterval();
  84
  85   bool IsValid() const { return interval >= base::TimeDelta(); }
  86
  87   scoped_refptr<base::debug::ConvertableToTraceFormat> AsValue() const;
  88   void AsValueInto(base::debug::TracedValue* dict) const;
  89
  90   base::TimeTicks frame_time;
  91   base::TimeTicks deadline;
  92   base::TimeDelta interval;
  93   BeginFrameArgsType type;
  94
  95  private:
  96   BeginFrameArgs(base::TimeTicks frame_time,
  97                  base::TimeTicks deadline,
  98                  base::TimeDelta interval,
  99                  BeginFrameArgsType type);
 100 };
 101
 102 }  // namespace cc
 103
 104 #endif  // CC_OUTPUT_BEGIN_FRAME_ARGS_H_