[ltt-dev] [BABELTRACE PATCH] Add callback support

Mathieu Desnoyers mathieu.desnoyers at efficios.com
Tue Sep 13 14:53:20 EDT 2011


* Julien Desfossez (julien.desfossez at polymtl.ca) wrote:
> This patchs provides the code to add callbacks per event or for each
> events. For now the priority is not handled so the callbacks are
> processed in a FIFO manner and global callbacks are processed before
> per-event callbacks.
> 
> Signed-off-by: Julien Desfossez <julien.desfossez at polymtl.ca>
> ---
>  converter/babeltrace-lib.c |  170 +++++++++++++++++++++++++++++++++++++++++++-
>  1 files changed, 169 insertions(+), 1 deletions(-)
> 
> diff --git a/converter/babeltrace-lib.c b/converter/babeltrace-lib.c
> index 86fadc4..b1543df 100644
> --- a/converter/babeltrace-lib.c
> +++ b/converter/babeltrace-lib.c
> @@ -52,6 +52,10 @@ struct babeltrace_saved_pos {
>  struct bt_callback {
>  	int prio;		/* Callback order priority. Lower first. Dynamically assigned from dependency graph. */
>  	void *private_data;
> +	int flags;
> +	struct bt_dependencies *depends;
> +	struct bt_dependencies *weak_depends;
> +	struct bt_dependencies *provides;
>  	enum bt_cb_ret (*callback)(void *private_data, void *caller_data);
>  };
>  
> @@ -75,7 +79,7 @@ struct babeltrace_iter {
>  	struct ptr_heap *stream_heap;
>  	struct trace_collection *tc;
>  	struct trace_collection_pos *end_pos;
> -	GArray *callbacks;				/* Array of struct bt_stream_hooks */
> +	GArray *callbacks;				/* Array of struct bt_stream_callbacks */
>  	struct bt_callback_chain main_callbacks;	/* For all events */
>  	/*
>  	 * Flag indicating if dependency graph needs to be recalculated.
> @@ -129,6 +133,102 @@ struct bt_dependencies *babeltrace_dependencies_create(const char *first, ...)
>  	return deps;
>  }
>  
> +/*
> + * babeltrace_iter_add_callback: Add a callback to iterator.
> + */
> +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)
> +{
> +	int i, stream_id;
> +	gpointer *event_id_ptr;
> +	unsigned long event_id;
> +	struct trace_collection *tc = iter->tc;
> +
> +	for (i = 0; i < tc->array->len; i++) {
> +		struct ctf_trace *tin;
> +		struct trace_descriptor *td_read;
> +
> +		td_read = g_ptr_array_index(tc->array, i);
> +		tin = container_of(td_read, struct ctf_trace, parent);
> +
> +		for (stream_id = 0; stream_id < tin->streams->len; stream_id++) {
> +			struct ctf_stream_class *stream;
> +			struct bt_stream_callbacks *bt_stream_cb = NULL;
> +			struct bt_callback_chain *bt_chain = NULL;
> +			struct bt_callback new_callback;
> +
> +			stream = g_ptr_array_index(tin->streams, stream_id);
> +
> +			/* find or create the bt_stream_callbacks for this stream */
> +			if (iter->callbacks->len >= stream_id) {
> +				bt_stream_cb = &g_array_index(iter->callbacks,
> +						struct bt_stream_callbacks, stream->stream_id);
> +			} else {
> +				g_array_set_size(iter->callbacks, stream->stream_id);
> +			}
> +			if (!bt_stream_cb || !bt_stream_cb->per_id_callbacks) {
> +				struct bt_stream_callbacks new_stream_cb;
> +				new_stream_cb.per_id_callbacks = g_array_new(1, 1,
> +						sizeof(struct bt_callback_chain));
> +				g_array_insert_val(iter->callbacks, stream->stream_id, new_stream_cb);
> +				bt_stream_cb = &g_array_index(iter->callbacks,
> +						struct bt_stream_callbacks, stream->stream_id);
> +			}
> +
> +			if (event) {
> +				/* find the event id */
> +				event_id_ptr = g_hash_table_lookup(stream->event_quark_to_id,
> +						(GQuark)event);

Please add space between (type) and variable for casts.

And to remove warnings:

(gconstpointer) (unsigned long) event

> +				/* event not found in this stream class */
> +				if (!event_id_ptr) {
> +					printf("event not found\n");
> +					continue;
> +				}
> +				event_id = (uint64_t)*event_id_ptr;
> +
> +				/* find or create the bt_callback_chain for this event */
> +				if (bt_stream_cb->per_id_callbacks->len >= event_id) {
> +					bt_chain = &g_array_index(bt_stream_cb->per_id_callbacks,
> +							struct bt_callback_chain, event_id);
> +				} else {
> +					g_array_set_size(bt_stream_cb->per_id_callbacks, event_id);
> +				}
> +				if (!bt_chain || !bt_chain->callback) {
> +					struct bt_callback_chain new_chain;
> +					new_chain.callback = g_array_new(1, 1, sizeof(struct bt_callback));
> +					g_array_insert_val(bt_stream_cb->per_id_callbacks, event_id,
> +							new_chain);
> +					bt_chain = &g_array_index(bt_stream_cb->per_id_callbacks,
> +							struct bt_callback_chain, event_id);
> +				}
> +			} else {
> +				/* callback for all events */
> +				if (!iter->main_callbacks.callback) {
> +					iter->main_callbacks.callback = g_array_new(1, 1,
> +							sizeof(struct bt_callback));
> +				}
> +				bt_chain = &iter->main_callbacks;
> +			}
> +
> +			new_callback.private_data = private_data;
> +			new_callback.flags = flags;
> +			new_callback.callback = callback;
> +			new_callback.depends = depends;
> +			new_callback.weak_depends = weak_depends;
> +			new_callback.provides = provides;
> +
> +			/* TODO : take care of priority, for now just FIFO */
> +			g_array_append_val(bt_chain->callback, new_callback);
> +		}
> +	}
> +
> +	return 0;
> +}
> +
>  static int stream_read_event(struct ctf_file_stream *sin)
>  {
>  	int ret;
> @@ -243,6 +343,10 @@ struct babeltrace_iter *babeltrace_iter_create(struct trace_collection *tc,
>  	iter->stream_heap = g_new(struct ptr_heap, 1);
>  	iter->tc = tc;
>  	iter->end_pos = end_pos;
> +	iter->callbacks = g_array_new(1, 1, sizeof(struct bt_stream_callbacks));

g_array_new(0, 1, ...)   (no need to be zero-terminated right ?)

Thanks,

Mathieu

> +	iter->recalculate_dep_graph = 0;
> +	iter->main_callbacks.callback = NULL;
> +	iter->dep_gc = g_ptr_array_new();
>  
>  	ret = heap_init(iter->stream_heap, 0, stream_compare);
>  	if (ret < 0)
> @@ -336,6 +440,64 @@ end:
>  	return ret;
>  }
>  
> +static
> +void process_callbacks(struct babeltrace_iter *iter,
> +		struct ctf_stream *stream)
> +{
> +	struct bt_stream_callbacks *bt_stream_cb;
> +	struct bt_callback_chain *bt_chain;
> +	struct bt_callback *cb;
> +	int i;
> +	enum bt_cb_ret ret;
> +
> +	/* process all events callback first */
> +	if (iter->main_callbacks.callback) {
> +		for (i = 0; i < iter->main_callbacks.callback->len; i++) {
> +			cb = &g_array_index(iter->main_callbacks.callback, struct bt_callback, i);
> +			if (!cb)
> +				goto end;
> +			ret = cb->callback(NULL, NULL);
> +			switch (ret) {
> +				case BT_CB_OK_STOP:
> +				case BT_CB_ERROR_STOP:
> +					goto end;
> +				default:
> +					break;
> +			}
> +		}
> +	}
> +
> +	/* process per event callbacks */
> +	bt_stream_cb = &g_array_index(iter->callbacks,
> +			struct bt_stream_callbacks, stream->stream_id);
> +	if (!bt_stream_cb || !bt_stream_cb->per_id_callbacks)
> +		goto end;
> +
> +	if (stream->event_id > bt_stream_cb->per_id_callbacks->len)
> +		goto end;
> +	bt_chain = &g_array_index(bt_stream_cb->per_id_callbacks,
> +			struct bt_callback_chain, stream->event_id);
> +	if (!bt_chain || !bt_chain->callback)
> +		goto end;
> +
> +	for (i = 0; i < bt_chain->callback->len; i++) {
> +		cb = &g_array_index(bt_chain->callback, struct bt_callback, i);
> +		if (!cb)
> +			goto end;
> +		ret = cb->callback(NULL, NULL);
> +		switch (ret) {
> +		case BT_CB_OK_STOP:
> +		case BT_CB_ERROR_STOP:
> +			goto end;
> +		default:
> +			break;
> +		}
> +	}
> +
> +end:
> +	return;
> +}
> +
>  int babeltrace_iter_read_event(struct babeltrace_iter *iter,
>  		struct ctf_stream **stream,
>  		struct ctf_stream_event **event)
> @@ -351,6 +513,12 @@ int babeltrace_iter_read_event(struct babeltrace_iter *iter,
>  	}
>  	*stream = &file_stream->parent;
>  	*event = g_ptr_array_index((*stream)->events_by_id, (*stream)->event_id);
> +
> +	if ((*stream)->stream_id > iter->callbacks->len)
> +		goto end;
> +
> +	process_callbacks(iter, *stream);
> +
>  end:
>  	return ret;
>  }
> -- 
> 1.7.5.4
> 

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com




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