[v3,20/24] instrument: Add client-side API to control tracing state of events

diff --git a/instrument/Makefile.objs b/instrument/Makefile.objs
index 1fcf77e..cd55f6f 100644
--- a/instrument/Makefile.objs
+++ b/instrument/Makefile.objs
@@ -82,5 +82,6 @@  common-obj-$(CONFIG_SOFTMMU) += qmp.o
 common-obj-$(CONFIG_SOFTMMU) += hmp.o
 
 target-obj-y += api-control.o
+target-obj-y += api-trace.o
 
 QEMU_CFLAGS += -I$(BUILD_DIR)/instrument -I$(SRC_PATH)/instrument
diff --git a/instrument/api-trace.c b/instrument/api-trace.c
new file mode 100644
index 0000000..97e135a
--- /dev/null
+++ b/instrument/api-trace.c
@@ -0,0 +1,14 @@ 
+/*
+ * Interface for controlling the tracing state of events.
+ *
+ * Copyright (C) 2012-2013 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.
+ */
+
+#include "instrument/qemu-instr/trace.h"
+
+#if defined(QI_TYPE_CONFIG_DYNAMIC)
+#include "instrument/qemu-instr/trace-internal.h"
+#endif
diff --git a/instrument/qemu-instr/trace-internal.h b/instrument/qemu-instr/trace-internal.h
new file mode 100644
index 0000000..2d6eec4
--- /dev/null
+++ b/instrument/qemu-instr/trace-internal.h
@@ -0,0 +1,32 @@ 
+/*
+ * Interface for controlling the tracing state of events.
+ *
+ * Copyright (C) 2012-2013 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 QI__TRACE_INTERNAL_H
+#define QI__TRACE_INTERNAL_H
+
+#include "trace/control.h"
+
+
+QI_IDEF bool qi_trace_event_get_state_static(QIEvent *ev)
+{
+    return trace_event_get_state_static((TraceEvent*)ev);
+}
+
+QI_IDEF bool qi_trace_event_get_state_dynamic(QIEvent *ev)
+{
+    return trace_event_get_state_dynamic((TraceEvent*)ev);
+}
+
+QI_IDEF void qi_trace_event_set_state_dynamic(QIEvent *ev, bool state)
+{
+    assert(qi_trace_event_get_state_static(ev));
+    return trace_event_set_state_dynamic((TraceEvent*)ev, state);
+}
+
+#endif  /* QI__TRACE_INTERNAL_H */
diff --git a/instrument/qemu-instr/trace.h b/instrument/qemu-instr/trace.h
new file mode 100644
index 0000000..fd9172a
--- /dev/null
+++ b/instrument/qemu-instr/trace.h
@@ -0,0 +1,91 @@ 
+/*
+ * Interface for controlling the tracing state of events.
+ *
+ * Copyright (C) 2012-2013 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 QI__TRACE_H
+#define QI__TRACE_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdbool.h>
+
+#include <qemu-instr/control.h>
+
+
+/**
+ * SECTION: trace
+ * @section_id: qi-trace
+ * @title: QEMU tracing event control interface
+ */
+
+/**
+ * qi_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 #QIEventID value.
+ */
+#define qi_trace_event_get_state(id)                                    \
+    ((id ##_ENABLED) && qi_trace_event_get_state_dynamic(qi_ctrl_event_id(id)))
+
+/**
+ * qi_trace_event_get_state_static:
+ * @id: Event identifier.
+ *
+ * Get the static tracing state of an event.
+ *
+ * Use the define 'QI_EVENT_${EVENT}_ENABLED' for compile-time checks (it will
+ * be set to 1 or 0 according to the presence of the disabled property).
+ */
+QI_IDECL bool qi_trace_event_get_state_static(QIEvent *ev);
+
+/**
+ * qi_trace_event_get_state_dynamic:
+ *
+ * Get the dynamic tracing state of an event.
+ */
+QI_IDECL bool qi_trace_event_get_state_dynamic(QIEvent *ev);
+
+/**
+ * qi_trace_event_set_state:
+ *
+ * Set the tracing state of an event.
+ */
+#define qi_trace_event_set_state(id, state)                     \
+    do {                                                        \
+        if ((id ##_ENABLED)) {                                  \
+            QIEvent *_e = qi_ctrl_event_id(id);                 \
+            qi_trace_event_set_state_dynamic(_e, state);        \
+        }                                                       \
+    } while (0)
+
+/**
+ * qi_trace_event_set_state_dynamic:
+ *
+ * Set the dynamic tracing state of an event.
+ *
+ * Pre-condition: qi_trace_event_get_state_static(ev) == true
+ */
+QI_IDECL void qi_trace_event_set_state_dynamic(QIEvent *ev, bool state);
+
+
+#if !defined(QI_TYPE_CONFIG_DYNAMIC)
+#include "instrument/qemu-instr/trace-internal.h"
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  /* QI__TRACE_H */