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      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 UI_EVENTS_LATENCY_INFO_H_
      6 #define UI_EVENTS_LATENCY_INFO_H_
      7 
      8 #include <utility>
      9 #include <vector>
     10 
     11 #include "base/basictypes.h"
     12 #include "base/containers/small_map.h"
     13 #include "base/time/time.h"
     14 #include "ui/events/events_base_export.h"
     15 
     16 namespace ui {
     17 
     18 enum LatencyComponentType {
     19   // ---------------------------BEGIN COMPONENT-------------------------------
     20   // BEGIN COMPONENT is when we show the latency begin in chrome://tracing.
     21   // Timestamp when the input event is sent from RenderWidgetHost to renderer.
     22   INPUT_EVENT_LATENCY_BEGIN_RWH_COMPONENT,
     23   // Timestamp when the input event is received in plugin.
     24   INPUT_EVENT_LATENCY_BEGIN_PLUGIN_COMPONENT,
     25   // ---------------------------NORMAL COMPONENT-------------------------------
     26   // Timestamp when the scroll update gesture event is sent from RWH to
     27   // renderer. In Aura, touch event's LatencyInfo is carried over to the gesture
     28   // event. So gesture event's INPUT_EVENT_LATENCY_RWH_COMPONENT is the
     29   // timestamp when its original touch events is sent from RWH to renderer.
     30   // In non-aura platform, INPUT_EVENT_LATENCY_SCROLL_UPDATE_RWH_COMPONENT
     31   // is the same as INPUT_EVENT_LATENCY_RWH_COMPONENT.
     32   INPUT_EVENT_LATENCY_SCROLL_UPDATE_RWH_COMPONENT,
     33   // The original timestamp of the touch event which converts to scroll update.
     34   INPUT_EVENT_LATENCY_SCROLL_UPDATE_ORIGINAL_COMPONENT,
     35   // Original timestamp for input event (e.g. timestamp from kernel).
     36   INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT,
     37   // Timestamp when the UI event is created.
     38   INPUT_EVENT_LATENCY_UI_COMPONENT,
     39   // This is special component indicating there is rendering scheduled for
     40   // the event associated with this LatencyInfo.
     41   INPUT_EVENT_LATENCY_RENDERING_SCHEDULED_COMPONENT,
     42   // Timestamp when the touch event is acked.
     43   INPUT_EVENT_LATENCY_ACKED_TOUCH_COMPONENT,
     44   // Frame number when a window snapshot was requested. The snapshot
     45   // is taken when the rendering results actually reach the screen.
     46   WINDOW_SNAPSHOT_FRAME_NUMBER_COMPONENT,
     47   // ---------------------------TERMINAL COMPONENT-----------------------------
     48   // TERMINAL COMPONENT is when we show the latency end in chrome://tracing.
     49   // Timestamp when the mouse event is acked from renderer and it does not
     50   // cause any rendering scheduled.
     51   INPUT_EVENT_LATENCY_TERMINATED_MOUSE_COMPONENT,
     52   // Timestamp when the touch event is acked from renderer and it does not
     53   // cause any rendering schedueld and does not generate any gesture event.
     54   INPUT_EVENT_LATENCY_TERMINATED_TOUCH_COMPONENT,
     55   // Timestamp when the gesture event is acked from renderer, and it does not
     56   // cause any rendering schedueld.
     57   INPUT_EVENT_LATENCY_TERMINATED_GESTURE_COMPONENT,
     58   // Timestamp when the frame is swapped (i.e. when the rendering caused by
     59   // input event actually takes effect).
     60   INPUT_EVENT_LATENCY_TERMINATED_FRAME_SWAP_COMPONENT,
     61   // This component indicates that the input causes a commit to be scheduled
     62   // but the commit failed.
     63   INPUT_EVENT_LATENCY_TERMINATED_COMMIT_FAILED_COMPONENT,
     64   // This component indicates that the input causes a swap to be scheduled
     65   // but the swap failed.
     66   INPUT_EVENT_LATENCY_TERMINATED_SWAP_FAILED_COMPONENT,
     67   // This component indicates that the cached LatencyInfo number exceeds the
     68   // maximal allowed size.
     69   LATENCY_INFO_LIST_TERMINATED_OVERFLOW_COMPONENT,
     70   // Timestamp when the input event is considered not cause any rendering
     71   // damage in plugin and thus terminated.
     72   INPUT_EVENT_LATENCY_TERMINATED_PLUGIN_COMPONENT,
     73   LATENCY_COMPONENT_TYPE_LAST = INPUT_EVENT_LATENCY_TERMINATED_PLUGIN_COMPONENT
     74 };
     75 
     76 struct EVENTS_BASE_EXPORT LatencyInfo {
     77   struct LatencyComponent {
     78     // Nondecreasing number that can be used to determine what events happened
     79     // in the component at the time this struct was sent on to the next
     80     // component.
     81     int64 sequence_number;
     82     // Average time of events that happened in this component.
     83     base::TimeTicks event_time;
     84     // Count of events that happened in this component
     85     uint32 event_count;
     86   };
     87 
     88   // Empirically determined constant based on a typical scroll sequence.
     89   enum { kTypicalMaxComponentsPerLatencyInfo = 6 };
     90 
     91   // Map a Latency Component (with a component-specific int64 id) to a
     92   // component info.
     93   typedef base::SmallMap<
     94       std::map<std::pair<LatencyComponentType, int64>, LatencyComponent>,
     95       kTypicalMaxComponentsPerLatencyInfo> LatencyMap;
     96 
     97   LatencyInfo();
     98 
     99   ~LatencyInfo();
    100 
    101   // Returns true if the vector |latency_info| is valid. Returns false
    102   // if it is not valid and log the |referring_msg|.
    103   // This function is mainly used to check the latency_info vector that
    104   // is passed between processes using IPC message has reasonable size
    105   // so that we are confident the IPC message is not corrupted/compromised.
    106   // This check will go away once the IPC system has better built-in scheme
    107   // for corruption/compromise detection.
    108   static bool Verify(const std::vector<LatencyInfo>& latency_info,
    109                      const char* referring_msg);
    110 
    111   // Copy LatencyComponents with type |type| from |other| into |this|.
    112   void CopyLatencyFrom(const LatencyInfo& other, LatencyComponentType type);
    113 
    114   // Add LatencyComponents that are in |other| but not in |this|.
    115   void AddNewLatencyFrom(const LatencyInfo& other);
    116 
    117   // Modifies the current sequence number for a component, and adds a new
    118   // sequence number with the current timestamp.
    119   void AddLatencyNumber(LatencyComponentType component,
    120                         int64 id,
    121                         int64 component_sequence_number);
    122 
    123   // Modifies the current sequence number and adds a certain number of events
    124   // for a specific component.
    125   void AddLatencyNumberWithTimestamp(LatencyComponentType component,
    126                                      int64 id,
    127                                      int64 component_sequence_number,
    128                                      base::TimeTicks time,
    129                                      uint32 event_count);
    130 
    131   // Returns true if the a component with |type| and |id| is found in
    132   // the latency_components and the component is stored to |output| if
    133   // |output| is not NULL. Returns false if no such component is found.
    134   bool FindLatency(LatencyComponentType type,
    135                    int64 id,
    136                    LatencyComponent* output) const;
    137 
    138   void RemoveLatency(LatencyComponentType type);
    139 
    140   void Clear();
    141 
    142   // Records the |event_type| in trace buffer as TRACE_EVENT_ASYNC_STEP.
    143   void TraceEventType(const char* event_type);
    144 
    145   LatencyMap latency_components;
    146   // The unique id for matching the ASYNC_BEGIN/END trace event.
    147   int64 trace_id;
    148   // Whether a terminal component has been added.
    149   bool terminated;
    150 };
    151 
    152 }  // namespace ui
    153 
    154 #endif  // UI_EVENTS_LATENCY_INFO_H_
    155