text: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
  /* 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/. */
  
  /* *************** SPS Sampler Information ****************
   *
   * SPS is an always on profiler that takes fast and low overheads samples
   * of the program execution using only userspace functionity for portability.
   * The goal of this module is to provide performance data in a generic
   * cross platform way without requiring custom tools or kernel support.
   *
   * Non goals: Support features that are platform specific or replace
   *            platform specific profilers.
   *
   * Samples are collected to form a timeline with optional timeline event (markers)
   * used for filtering.
   *
   * SPS collects samples in a platform independant way by using a speudo stack abstraction
   * of the real program stack by using 'sample stack frames'. When a sample is collected
   * all active sample stack frames and the program counter are recorded.
   */
  
  /* *************** SPS Sampler File Format ****************
   *
   * Simple new line seperated tag format:
   * S      -> BOF tags EOF
   * tags   -> tag tags
   * tag    -> CHAR - STRING
   *
   * Tags:
   * 's' - Sample tag followed by the first stack frame followed by 0 or more 'c' tags.
   * 'c' - Continue Sample tag gives remaining tag element. If a 'c' tag is seen without
   *         a preceding 's' tag it should be ignored. This is to support the behavior
   *         of circular buffers.
   *         If the 'stackwalk' feature is enabled this tag will have the format
   *         'l-<library name>@<hex address>' and will expect an external tool to translate
   *         the tag into something readable through a symbolication processing step.
   * 'm' - Timeline marker. Zero or more may appear before a 's' tag.
   * 'l' - Information about the program counter library and address. Post processing
   *         can include function and source line. If built with leaf data enabled
   *         this tag will describe the last 'c' tag.
   * 'r' - Responsiveness tag following an 's' tag. Gives an indication on how well the
   *          application is responding to the event loop. Lower is better.
   * 't' - Elapse time since recording started.
   *
   */
  
  #ifndef SAMPLER_H
  #define SAMPLER_H
  
  // Redefine the macros for platforms where SPS is supported.
  #ifdef MOZ_ENABLE_PROFILER_SPS
  
  #include "sps_sampler.h"
  
  #else
  
  // Initialize the sampler. Any other calls will be silently discarded
  // before the sampler has been initialized (i.e. early start-up code)
  #define SAMPLER_INIT()
  #define SAMPLER_DEINIT()
  #define SAMPLER_START(entries, interval, features, featureCount)
  #define SAMPLER_STOP()
  #define SAMPLER_IS_ACTIVE() false
  #define SAMPLER_SAVE()
  // Returned string must be free'ed
  #define SAMPLER_GET_PROFILE() NULL
  #define SAMPLER_GET_PROFILE_DATA(ctx) NULL
  #define SAMPLER_RESPONSIVENESS(time) NULL
  #define SAMPLER_GET_RESPONSIVENESS() NULL
  #define SAMPLER_GET_FEATURES() NULL
  #define SAMPLE_LABEL(name_space, info)
  // Provide a default literal string to use if profiling is disabled
  // and a printf argument to be computed if profiling is enabled.
  // NOTE: This will store the formated string on the stack and consume
  //       over 128 bytes on the stack.
  #define SAMPLE_LABEL_PRINTF(name_space, info, format, ...)
  #define SAMPLE_LABEL_FN(name_space, info)
  #define SAMPLE_MARKER(info)
  
  #endif
  
  #endif // ifndef SAMPLER_H
  