Add callback API

[babeltrace.git] / include / babeltrace / babeltrace.h

diff --git a/include/babeltrace/babeltrace.h b/include/babeltrace/babeltrace.h
index 6c3fe967e635ee05973a08c3d35dcdc027e9b64f..eb15de005843f1044636d41941fd49b4b1eec8d1 100644 (file)
--- a/include/babeltrace/babeltrace.h
+++ b/include/babeltrace/babeltrace.h
@@ -17,12 +17,24 @@
  * all copies or substantial portions of the Software.
  */
 
+#include <glib.h>
+
+typedef GQuark bt_event_name;
+
 /* Forward declarations */
 struct babeltrace_iter;
 struct trace_collection;
 struct ctf_stream_event;
 struct ctf_stream;
 struct babeltrace_saved_pos;
+struct bt_dependencies;
+
+enum bt_cb_ret {
+       BT_CB_OK                = 0,
+       BT_CB_OK_STOP           = 1,
+       BT_CB_ERROR_STOP        = 2,
+       BT_CB_ERROR_CONTINUE    = 3,
+};
 
 struct trace_collection_pos {
        enum {
@@ -102,4 +114,65 @@ int babeltrace_iter_read_event(struct babeltrace_iter *iter,
                struct ctf_stream **stream,
                struct ctf_stream_event **event);
 
+/*
+ * Receives a variable number of strings as parameter, ended with NULL.
+ */
+struct bt_dependencies *babeltrace_dependencies_create(const char *first, ...);
+
+/*
+ * struct bt_dependencies must be destroyed explicitly if not passed as
+ * parameter to a babeltrace_iter_add_callback().
+ */
+void babeltrace_dependencies_destroy(struct bt_dependencies *dep);
+
+/*
+ * babeltrace_iter_add_callback: Add a callback to iterator.
+ *
+ * @iter: trace collection iterator (input)
+ * @event: event to target. 0 for all events.
+ * @private_data: private data pointer to pass to the callback
+ * @flags: specific flags controlling the behavior of this callback
+ *         (or'd).
+ *            
+ * @callback: function pointer to call
+ * @depends: struct bt_dependency detailing the required computation results.
+ *           Ends with 0.
+ * @weak_depends: struct bt_dependency detailing the optional computation
+ *                results that can be optionally consumed by this
+ *                callback.
+ * @provides: struct bt_dependency detailing the computation results
+ *            provided by this callback.
+ *            Ends with 0.
+ *
+ * "depends", "weak_depends" and "provides" memory is handled by the
+ * babeltrace library after this call succeeds or fails. These objects
+ * can still be used by the caller until the babeltrace iterator is
+ * destroyed, but they belong to the babeltrace library.
+ *
+ * (note to implementor: we need to keep a gptrarray of struct
+ * bt_dependencies to "garbage collect" in struct babeltrace_iter, and
+ * dependencies need to have a refcount to handle the case where they
+ * would be passed to more than one iterator. Upon iterator detroy, we
+ * iterate on all the gc ptrarray and decrement the refcounts, freeing
+ * if we reach 0.)
+ * (note to implementor: we calculate the dependency graph when
+ * babeltrace_iter_read_event() is executed after a
+ * babeltrace_iter_add_callback(). Beware that it is valid to create/add
+ * callbacks/read/add more callbacks/read some more.)
+ */
+int babeltrace_iter_add_callback(struct babeltrace_iter *iter,
+               bt_event_name event, void *private_data, int flags,
+               enum bt_cb_ret (*callback)(void *private_data,
+                                       void *caller_data),
+               struct bt_dependencies *depends,
+               struct bt_dependencies *weak_depends,
+               struct bt_dependencies *provides);
+
+/*
+ * For flags parameter above.
+ */
+enum {
+       BT_FLAGS_FREE_PRIVATE_DATA      = (1 << 0),
+};
+
 #endif /* _BABELTRACE_H */