summaryrefslogtreecommitdiffstats
path: root/xpcom/build/perfprobe.h
blob: e5a0382322747e1603a862bd7534307cd38564b3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/**
 * A mechanism for interacting with operating system-provided
 * debugging/profiling tools such as Microsoft EWT/Windows Performance Toolkit.
 */

#ifndef mozilla_perfprobe_h
#define mozilla_perfprobe_h

#if !defined(XP_WIN)
#  error "For the moment, perfprobe.h is defined only for Windows platforms"
#endif

#include "nsError.h"
#include "nsString.h"
#include "mozilla/Logging.h"
#include "nsTArray.h"
#include <windows.h>
#undef GetStartupInfo  // Prevent Windows from polluting global namespace
#include <wmistr.h>
#include <evntrace.h>

namespace mozilla {
namespace probes {

class ProbeManager;

/**
 * A data structure supporting a trigger operation that can be used to
 * send information to the operating system.
 */

class Probe {
 public:
  NS_INLINE_DECL_REFCOUNTING(Probe)

  /**
   * Trigger the event.
   *
   * Note: Can be called from any thread.
   */
  nsresult Trigger();

 protected:
  ~Probe(){};

  Probe(const nsCID& aGUID, const nsACString& aName, ProbeManager* aManager);
  friend class ProbeManager;

 protected:
  /**
   * The system GUID associated to this probe. See the documentation
   * of |ProbeManager::Make| for more details.
   */
  const GUID mGUID;

  /**
   * The name of this probe. See the documentation
   * of |ProbeManager::Make| for more details.
   */
  const nsCString mName;

  /**
   * The ProbeManager managing this probe.
   *
   * Note: This is a weak reference to avoid a useless cycle.
   */
  class ProbeManager* mManager;
};

/**
 * A manager for a group of probes.
 *
 * You can have several managers in one application, provided that they all
 * have distinct IDs and names. However, having more than 2 is considered a bad
 * practice.
 */
class ProbeManager {
 public:
  NS_INLINE_DECL_REFCOUNTING(ProbeManager)

  /**
   * Create a new probe manager.
   *
   * This constructor should be called from the main thread.
   *
   * @param aApplicationUID The unique ID of the probe. Under Windows, this
   * unique ID must have been previously registered using an external tool.
   * See MyCategory on http://msdn.microsoft.com/en-us/library/aa364100.aspx
   * @param aApplicationName A name for the probe. Currently used only for
   * logging purposes. In the future, may be attached to the data sent to the
   * operating system.
   *
   * Note: If two ProbeManagers are constructed with the same uid and/or name,
   * behavior is unspecified.
   */
  ProbeManager(const nsCID& aApplicationUID,
               const nsACString& aApplicationName);

  /**
   * Acquire a probe.
   *
   * Note: Only probes acquired before the call to SetReady are taken into
   * account
   * Note: Can be called only from the main thread.
   *
   * @param aEventUID The unique ID of the probe. Under Windows, this unique
   * ID must have been previously registered using an external tool.
   * See MyCategory on http://msdn.microsoft.com/en-us/library/aa364100.aspx
   * @param aEventName A name for the probe. Currently used only for logging
   * purposes. In the
   * future, may be attached to the data sent to the operating system.
   * @return Either |null| in case of error or a valid |Probe*|.
   *
   * Note: If this method is called twice with the same uid and/or name,
   * behavior is undefined.
   */
  already_AddRefed<Probe> GetProbe(const nsCID& aEventUID,
                                   const nsACString& aEventName);

  /**
   * Start/stop the measuring session.
   *
   * This method should be called from the main thread.
   *
   * Note that starting an already started probe manager has no effect,
   * nor does stopping an already stopped probe manager.
   */
  nsresult StartSession();
  nsresult StopSession();

  /**
   * @return true If measures are currently on, i.e. if triggering probes is any
   * is useful. You do not have to check this before triggering a probe, unless
   * this can avoid complex computations.
   */
  bool IsActive();

 protected:
  ~ProbeManager();

  nsresult StartSession(nsTArray<RefPtr<Probe>>& aProbes);
  nsresult Init(const nsCID& aApplicationUID,
                const nsACString& aApplicationName);

 protected:
  /**
   * `true` if a session is in activity, `false` otherwise.
   */
  bool mIsActive;

  /**
   * The UID of this manager.
   * See documentation above for registration steps that you
   * may have to take.
   */
  nsCID mApplicationUID;

  /**
   * The name of the application.
   */
  nsCString mApplicationName;

  /**
   * All the probes that have been created for this manager.
   */
  nsTArray<RefPtr<Probe>> mAllProbes;

  /**
   * Handle used for triggering events
   */
  TRACEHANDLE mSessionHandle;

  /**
   * Handle used for registration/unregistration
   */
  TRACEHANDLE mRegistrationHandle;

  /**
   * `true` if initialization has been performed, `false` until then.
   */
  bool mInitialized;

  friend class Probe;  // Needs to access |mSessionHandle|
  friend ULONG WINAPI ControlCallback(WMIDPREQUESTCODE aRequestCode,
                                      PVOID aContext, ULONG* aReserved,
                                      PVOID aBuffer);  // Sets |mSessionHandle|
};

}  // namespace probes
}  // namespace mozilla

#endif  // mozilla_perfprobe_h