text: /*
   * Interface for configuring and controlling the state of tracing events.
   *
   * Copyright (C) 2011-2012 Lluís Vilanova <vilanova@ac.upc.edu>
   *
   * This work is licensed under the terms of the GNU GPL, version 2 or later.
   * See the COPYING file in the top-level directory.
   */
  
  #ifndef TRACE__CONTROL_H
  #define TRACE__CONTROL_H
  
  #include "qemu-common.h"
  #include "trace/generated-events.h"
  
  
  /**
   * TraceEventID:
   *
   * Unique tracing event identifier.
   *
   * These are named as 'TRACE_${EVENT_NAME}'.
   *
   * See also: "trace/generated-events.h"
   */
  enum TraceEventID;
  
  /**
   * trace_event_id:
   * @id: Event identifier.
   *
   * Get an event by its identifier.
   *
   * This routine has a constant cost, as opposed to trace_event_name and
   * trace_event_pattern.
   *
   * Pre-conditions: The identifier is valid.
   *
   * Returns: pointer to #TraceEvent.
   *
   */
  static TraceEvent *trace_event_id(TraceEventID id);
  
  /**
   * trace_event_name:
   * @id: Event name.
   *
   * Search an event by its name.
   *
   * Returns: pointer to #TraceEvent or NULL if not found.
   */
  TraceEvent *trace_event_name(const char *name);
  
  /**
   * trace_event_pattern:
   * @pat: Event name pattern.
   * @ev: Event to start searching from (not included).
   *
   * Get all events with a given name pattern.
   *
   * Returns: pointer to #TraceEvent or NULL if not found.
   */
  TraceEvent *trace_event_pattern(const char *pat, TraceEvent *ev);
  
  /**
   * trace_event_is_pattern:
   *
   * Whether the given string is an event name pattern.
   */
  static bool trace_event_is_pattern(const char *str);
  
  /**
   * trace_event_count:
   *
   * Return the number of events.
   */
  static TraceEventID trace_event_count(void);
  
  
  
  /**
   * trace_event_get_id:
   *
   * Get the identifier of an event.
   */
  static TraceEventID trace_event_get_id(TraceEvent *ev);
  
  /**
   * trace_event_get_name:
   *
   * Get the name of an event.
   */
  static const char * trace_event_get_name(TraceEvent *ev);
  
  /**
   * trace_event_get_state:
   * @id: Event identifier.
   *
   * Get the tracing state of an event (both static and dynamic).
   *
   * If the event has the disabled property, the check will have no performance
   * impact.
   *
   * As a down side, you must always use an immediate #TraceEventID value.
   */
  #define trace_event_get_state(id)                       \
      ((id ##_ENABLED) && trace_event_get_state_dynamic(trace_event_id(id)))
  
  /**
   * trace_event_get_state_static:
   * @id: Event identifier.
   *
   * Get the static tracing state of an event.
   *
   * Use the define 'TRACE_${EVENT_NAME}_ENABLED' for compile-time checks (it will
   * be set to 1 or 0 according to the presence of the disabled property).
   */
  static bool trace_event_get_state_static(TraceEvent *ev);
  
  /**
   * trace_event_get_state_dynamic:
   *
   * Get the dynamic tracing state of an event.
   */
  static bool trace_event_get_state_dynamic(TraceEvent *ev);
  
  /**
   * trace_event_set_state:
   *
   * Set the tracing state of an event (only if possible).
   */
  #define trace_event_set_state(id, state)                \
      do {                                                \
          if ((id ##_ENABLED)) {                          \
              TraceEvent *_e = trace_event_id(id);        \
              trace_event_set_state_dynamic(_e, state);   \
          }                                               \
      } while (0)
  
  /**
   * trace_event_set_state_dynamic:
   *
   * Set the dynamic tracing state of an event.
   *
   * Pre-condition: trace_event_get_state_static(ev) == true
   */
  static void trace_event_set_state_dynamic(TraceEvent *ev, bool state);
  
  /**
   * trace_event_set_state_dynamic_backend:
   *
   * Warning: This function must be implemented by each tracing backend.
   */
  void trace_event_set_state_dynamic_backend(TraceEvent *ev, bool state);
  
  
  
  /**
   * trace_print_events:
   *
   * Print the state of all events.
   *
   * Warning: This function must be implemented by each tracing backend.
   */
  void trace_print_events(FILE *stream, fprintf_function stream_printf);
  
  /**
   * trace_backend_init:
   * @events: Name of file with events to be enabled at startup; may be NULL.
   *          Corresponds to commandline option "-trace events=...".
   * @file:   Name of trace output file; may be NULL.
   *          Corresponds to commandline option "-trace file=...".
   *
   * Initialize the tracing backend.
   *
   * Warning: This function must be implemented by each tracing backend.
   *
   * Returns: Whether the backend could be successfully initialized.
   */
  bool trace_backend_init(const char *events, const char *file);
  
  /**
   * trace_backend_init_events:
   * @fname: Name of file with events to enable; may be NULL.
   *
   * Generic function to initialize the state of events.
   */
  void trace_backend_init_events(const char *fname);
  
  
  #include "trace/control-internal.h"
  
  #endif  /* TRACE__CONTROL_H */
  