[babeltrace.git] / lib / iterator.c

/*
 * iterator.c
 *
 * Babeltrace Library
 *
 * Copyright 2010-2011 EfficiOS Inc. and Linux Foundation
 *
 * Author: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 */

#include <stdlib.h>
#include <babeltrace/babeltrace.h>
#include <babeltrace/context.h>
#include <babeltrace/context-internal.h>
#include <babeltrace/iterator-internal.h>
#include <babeltrace/iterator.h>
#include <babeltrace/prio_heap.h>
#include <babeltrace/ctf/metadata.h>
#include <babeltrace/ctf/events.h>
#include <inttypes.h>

struct stream_saved_pos {
	/*
	 * Use file_stream pointer to check if the trace collection we
	 * restore to match the one we saved from, for each stream.
	 */
	struct ctf_file_stream *file_stream;
	size_t cur_index;	/* current index in packet index */
	ssize_t offset;		/* offset from base, in bits. EOF for end of file. */
	uint64_t current_timestamp;
};

struct bt_saved_pos {
	struct trace_collection *tc;
	GArray *stream_saved_pos;	/* Contains struct stream_saved_pos */
};

static int stream_read_event(struct ctf_file_stream *sin)
{
	int ret;

	ret = sin->pos.parent.event_cb(&sin->pos.parent, &sin->parent);
	if (ret == EOF)
		return EOF;
	else if (ret) {
		fprintf(stderr, "[error] Reading event failed.\n");
		return ret;
	}
	return 0;
}

/*
 * returns true if a < b, false otherwise.
 */
int stream_compare(void *a, void *b)
{
	struct ctf_file_stream *s_a = a, *s_b = b;

	if (s_a->parent.timestamp < s_b->parent.timestamp)
		return 1;
	else
		return 0;
}

void bt_iter_free_pos(struct bt_iter_pos *iter_pos)
{
	if (!iter_pos)
		return;

	if (iter_pos->u.restore) {
		if (iter_pos->u.restore->stream_saved_pos) {
			g_array_free(
				iter_pos->u.restore->stream_saved_pos,
				TRUE);
		}
		g_free(iter_pos->u.restore);
	}
	g_free(iter_pos);
}

/*
 * seek_file_stream_by_timestamp
 *
 * Browse a filestream by index, if an index contains the timestamp passed in
 * argument, seek inside the corresponding packet it until we find the event we
 * are looking for (either the exact timestamp or the event just after the
 * timestamp).
 *
 * Return 0 if the seek succeded and EOF if we didn't find any packet
 * containing the timestamp.
 */
static int seek_file_stream_by_timestamp(struct ctf_file_stream *cfs,
		uint64_t timestamp)
{
	struct ctf_stream_pos *stream_pos;
	struct packet_index *index;
	int i, ret;

	stream_pos = &cfs->pos;
	for (i = 0; i < stream_pos->packet_index->len; i++) {
		index = &g_array_index(stream_pos->packet_index,
				struct packet_index, i);
		if (index->timestamp_end <= timestamp)
			continue;

		stream_pos->packet_seek(&stream_pos->parent, i, SEEK_SET);
		while (cfs->parent.timestamp < timestamp) {
			ret = stream_read_event(cfs);
			if (ret < 0)
				break;
		}
		return 0;
	}
	return EOF;
}

/*
 * seek_ctf_trace_by_timestamp : for each file stream, seek to the event with
 * the corresponding timestamp
 *
 * Return 0 on success.
 * If the timestamp is not part of any file stream, return EOF to inform the
 * user the timestamp is out of the scope
 */
static int seek_ctf_trace_by_timestamp(struct ctf_trace *tin,
		uint64_t timestamp, struct ptr_heap *stream_heap)
{
	int i, j, ret;
	int found = EOF;

	/* for each stream_class */
	for (i = 0; i < tin->streams->len; i++) {
		struct ctf_stream_class *stream_class;

		stream_class = g_ptr_array_index(tin->streams, i);
		/* for each file_stream */
		for (j = 0; j < stream_class->streams->len; j++) {
			struct ctf_stream *stream;
			struct ctf_file_stream *cfs;

			stream = g_ptr_array_index(stream_class->streams, j);
			cfs = container_of(stream, struct ctf_file_stream,
					parent);
			ret = seek_file_stream_by_timestamp(cfs, timestamp);
			if (ret == 0) {
				/* Add to heap */
				ret = heap_insert(stream_heap, cfs);
				if (ret)
					goto error;
				found = 0;
			}
		}
	}

	return found;

error:
	return -2;
}

int bt_iter_set_pos(struct bt_iter *iter, const struct bt_iter_pos *iter_pos)
{
	struct trace_collection *tc;
	int i, ret;

	switch (iter_pos->type) {
	case BT_SEEK_RESTORE:
		if (!iter_pos->u.restore)
			return -EINVAL;

		heap_free(iter->stream_heap);
		ret = heap_init(iter->stream_heap, 0, stream_compare);
		if (ret < 0)
			goto error;

		for (i = 0; i < iter_pos->u.restore->stream_saved_pos->len;
				i++) {
			struct stream_saved_pos *saved_pos;
			struct ctf_stream_pos *stream_pos;
			struct ctf_stream *stream;

			saved_pos = &g_array_index(
					iter_pos->u.restore->stream_saved_pos,
					struct stream_saved_pos, i);
			stream = &saved_pos->file_stream->parent;
			stream_pos = &saved_pos->file_stream->pos;

			stream_pos->packet_seek(&stream_pos->parent,
					saved_pos->cur_index, SEEK_SET);

			/*
			 * the timestamp needs to be restored after
			 * packet_seek, because this function resets
			 * the timestamp to the beginning of the packet
			 */
			stream->timestamp = saved_pos->current_timestamp;
			stream_pos->offset = saved_pos->offset;
			stream_pos->last_offset = saved_pos->offset;

			stream->prev_timestamp = 0;
			stream->prev_timestamp_end = 0;
			stream->consumed = 0;

			printf_debug("restored to cur_index = %zd and "
				"offset = %zd, timestamp = %" PRIu64 "\n",
				stream_pos->cur_index,
				stream_pos->offset, stream->timestamp);

			stream_read_event(saved_pos->file_stream);

			/* Add to heap */
			ret = heap_insert(iter->stream_heap,
					saved_pos->file_stream);
			if (ret)
				goto error;
		}
	case BT_SEEK_TIME:
		tc = iter->ctx->tc;

		heap_free(iter->stream_heap);
		ret = heap_init(iter->stream_heap, 0, stream_compare);
		if (ret < 0)
			goto error;

		/* for each trace in the trace_collection */
		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);

			ret = seek_ctf_trace_by_timestamp(tin,
					iter_pos->u.seek_time,
					iter->stream_heap);
			if (ret < 0)
				goto error;
		}
		return 0;
	default:
		/* not implemented */
		return -EINVAL;
	}

	return 0;

error:
	heap_free(iter->stream_heap);
	if (heap_init(iter->stream_heap, 0, stream_compare) < 0) {
		heap_free(iter->stream_heap);
		g_free(iter->stream_heap);
		iter->stream_heap = NULL;
		ret = -ENOMEM;
	}
	return ret;
}

struct bt_iter_pos *bt_iter_get_pos(struct bt_iter *iter)
{
	struct bt_iter_pos *pos;
	struct trace_collection *tc = iter->ctx->tc;
	int i, stream_class_id, stream_id;

	pos = g_new0(struct bt_iter_pos, 1);
	pos->u.restore = g_new0(struct bt_saved_pos, 1);
	pos->u.restore->tc = tc;
	pos->u.restore->stream_saved_pos = g_array_new(FALSE, TRUE,
			sizeof(struct stream_saved_pos));
	if (!pos->u.restore->stream_saved_pos)
		goto error;

	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_class_id = 0; stream_class_id < tin->streams->len;
				stream_class_id++) {
			struct ctf_stream_class *stream_class;

			stream_class = g_ptr_array_index(tin->streams,
					stream_class_id);
			for (stream_id = 0;
					stream_id < stream_class->streams->len;
					stream_id++) {
				struct ctf_stream *stream;
				struct ctf_file_stream *cfs;
				struct stream_saved_pos saved_pos;

				stream = g_ptr_array_index(
						stream_class->streams,
						stream_id);
				cfs = container_of(stream,
						struct ctf_file_stream,
						parent);

				saved_pos.file_stream = cfs;
				saved_pos.cur_index = cfs->pos.cur_index;

				/*
				 * It is possible that an event was read during
				 * the last restore, never consumed and its
				 * position saved again.  For this case, we
				 * need to check if the event really was
				 * consumed by the caller otherwise it is lost.
				 */
				if (stream->consumed)
					saved_pos.offset = cfs->pos.offset;
				else
					saved_pos.offset = cfs->pos.last_offset;

				saved_pos.current_timestamp = stream->timestamp;

				g_array_append_val(
					pos->u.restore->stream_saved_pos,
					saved_pos);

				printf_debug("stream : %" PRIu64 ", cur_index : %zd, "
					"offset : %zd, "
					"timestamp = %" PRIu64 "\n",
					stream->stream_id, saved_pos.cur_index,
					saved_pos.offset,
					saved_pos.current_timestamp);
			}
		}
	}

	return pos;

error:
	return NULL;
}

struct bt_iter_pos *bt_iter_create_time_pos(struct bt_iter *iter,
		uint64_t timestamp)
{
	struct bt_iter_pos *pos;

	pos = g_new0(struct bt_iter_pos, 1);
	pos->type = BT_SEEK_TIME;
	pos->u.seek_time = timestamp;
	return pos;
}

/*
 * babeltrace_filestream_seek: seek a filestream to given position.
 *
 * The stream_id parameter is only useful for BT_SEEK_RESTORE.
 */
static int babeltrace_filestream_seek(struct ctf_file_stream *file_stream,
		const struct bt_iter_pos *begin_pos,
		unsigned long stream_id)
{
	int ret = 0;

	switch (begin_pos->type) {
	case BT_SEEK_CUR:
		/*
		 * just insert into the heap we should already know
		 * the timestamps
		 */
		break;
	case BT_SEEK_BEGIN:
		file_stream->pos.packet_seek(&file_stream->pos.parent,
				0, SEEK_SET);
		ret = stream_read_event(file_stream);
		break;
	case BT_SEEK_TIME:
	case BT_SEEK_RESTORE:
	case BT_SEEK_END:
	default:
		assert(0); /* Not yet defined */
	}

	return ret;
}

/*
 * bt_iter_seek: seek iterator to given position.
 */
int bt_iter_seek(struct bt_iter *iter,
		const struct bt_iter_pos *begin_pos)
{
	int i, stream_id;
	int ret = 0;
	struct trace_collection *tc = iter->ctx->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);

		/* Populate heap with each stream */
		for (stream_id = 0; stream_id < tin->streams->len;
				stream_id++) {
			struct ctf_stream_class *stream;
			int filenr;

			stream = g_ptr_array_index(tin->streams, stream_id);
			for (filenr = 0; filenr < stream->streams->len;
					filenr++) {
				struct ctf_file_stream *file_stream;

				file_stream = g_ptr_array_index(stream->streams,
						filenr);
				ret = babeltrace_filestream_seek(file_stream, begin_pos,
						stream_id);
				if (ret < 0)
					goto end;
			}
		}
	}
end:
	return ret;
}

int bt_iter_init(struct bt_iter *iter,
		struct bt_context *ctx,
		const struct bt_iter_pos *begin_pos,
		const struct bt_iter_pos *end_pos)
{
	int i, stream_id;
	int ret = 0;

	iter->stream_heap = g_new(struct ptr_heap, 1);
	iter->end_pos = end_pos;
	bt_context_get(ctx);
	iter->ctx = ctx;

	ret = heap_init(iter->stream_heap, 0, stream_compare);
	if (ret < 0)
		goto error_heap_init;

	for (i = 0; i < ctx->tc->array->len; i++) {
		struct ctf_trace *tin;
		struct trace_descriptor *td_read;

		td_read = g_ptr_array_index(ctx->tc->array, i);
		tin = container_of(td_read, struct ctf_trace, parent);

		/* Populate heap with each stream */
		for (stream_id = 0; stream_id < tin->streams->len;
				stream_id++) {
			struct ctf_stream_class *stream;
			int filenr;

			stream = g_ptr_array_index(tin->streams, stream_id);
			if (!stream)
				continue;
			for (filenr = 0; filenr < stream->streams->len;
					filenr++) {
				struct ctf_file_stream *file_stream;

				file_stream = g_ptr_array_index(stream->streams,
						filenr);

				if (begin_pos) {
				    ret = babeltrace_filestream_seek(file_stream, begin_pos,
							stream_id);
				    if (ret == EOF) {
					   ret = 0;
					   continue;
				    } else if (ret) {
					   goto error;
				    }
				}
				/* Add to heap */
				ret = heap_insert(iter->stream_heap, file_stream);
				if (ret)
					goto error;
			}
		}
	}

	return 0;

error:
	heap_free(iter->stream_heap);
error_heap_init:
	g_free(iter->stream_heap);
	return ret;
}

struct bt_iter *bt_iter_create(struct bt_context *ctx,
		const struct bt_iter_pos *begin_pos,
		const struct bt_iter_pos *end_pos)
{
	struct bt_iter *iter;
	int ret;

	iter = g_new0(struct bt_iter, 1);
	ret = bt_iter_init(iter, ctx, begin_pos, end_pos);
	if (ret) {
		g_free(iter);
		return NULL;
	}
	return iter;
}

void bt_iter_fini(struct bt_iter *iter)
{
	if (iter->stream_heap) {
		heap_free(iter->stream_heap);
		g_free(iter->stream_heap);
	}
	bt_context_put(iter->ctx);
}

void bt_iter_destroy(struct bt_iter *iter)
{
	bt_iter_fini(iter);
	g_free(iter);
}

int bt_iter_next(struct bt_iter *iter)
{
	struct ctf_file_stream *file_stream, *removed;
	int ret;

	file_stream = heap_maximum(iter->stream_heap);
	if (!file_stream) {
		/* end of file for all streams */
		ret = 0;
		goto end;
	}

	ret = stream_read_event(file_stream);
	if (ret == EOF) {
		removed = heap_remove(iter->stream_heap);
		assert(removed == file_stream);
		ret = 0;
		goto end;
	} else if (ret) {
		goto end;
	}
	/* Reinsert the file stream into the heap, and rebalance. */
	removed = heap_replace_max(iter->stream_heap, file_stream);
	assert(removed == file_stream);

end:
	return ret;
}
Commit	Line	Data
	1	/*
	2	* iterator.c
	3	*
	4	* Babeltrace Library
	5	*
	6	* Copyright 2010-2011 EfficiOS Inc. and Linux Foundation
	7	*
	8	* Author: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	9	*
	10	* Permission is hereby granted, free of charge, to any person obtaining a copy
	11	* of this software and associated documentation files (the "Software"), to deal
	12	* in the Software without restriction, including without limitation the rights
	13	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	14	* copies of the Software, and to permit persons to whom the Software is
	15	* furnished to do so, subject to the following conditions:
	16	*
	17	* The above copyright notice and this permission notice shall be included in
	18	* all copies or substantial portions of the Software.
	19	*/
	20
	21	#include <stdlib.h>
	22	#include <babeltrace/babeltrace.h>
	23	#include <babeltrace/context.h>
	24	#include <babeltrace/context-internal.h>
	25	#include <babeltrace/iterator-internal.h>
	26	#include <babeltrace/iterator.h>
	27	#include <babeltrace/prio_heap.h>
	28	#include <babeltrace/ctf/metadata.h>
	29	#include <babeltrace/ctf/events.h>
	30	#include <inttypes.h>
	31
	32	struct stream_saved_pos {
	33	/*
	34	* Use file_stream pointer to check if the trace collection we
	35	* restore to match the one we saved from, for each stream.
	36	*/
	37	struct ctf_file_stream *file_stream;
	38	size_t cur_index; /* current index in packet index */
	39	ssize_t offset; /* offset from base, in bits. EOF for end of file. */
	40	uint64_t current_timestamp;
	41	};
	42
	43	struct bt_saved_pos {
	44	struct trace_collection *tc;
	45	GArray stream_saved_pos; / Contains struct stream_saved_pos */
	46	};
	47
	48	static int stream_read_event(struct ctf_file_stream *sin)
	49	{
	50	int ret;
	51
	52	ret = sin->pos.parent.event_cb(&sin->pos.parent, &sin->parent);
	53	if (ret == EOF)
	54	return EOF;
	55	else if (ret) {
	56	fprintf(stderr, "[error] Reading event failed.\n");
	57	return ret;
	58	}
	59	return 0;
	60	}
	61
	62	/*
	63	* returns true if a < b, false otherwise.
	64	*/
	65	int stream_compare(void a, void b)
	66	{
	67	struct ctf_file_stream s_a = a, s_b = b;
	68
	69	if (s_a->parent.timestamp < s_b->parent.timestamp)
	70	return 1;
	71	else
	72	return 0;
	73	}
	74
	75	void bt_iter_free_pos(struct bt_iter_pos *iter_pos)
	76	{
	77	if (!iter_pos)
	78	return;
	79
	80	if (iter_pos->u.restore) {
	81	if (iter_pos->u.restore->stream_saved_pos) {
	82	g_array_free(
	83	iter_pos->u.restore->stream_saved_pos,
	84	TRUE);
	85	}
	86	g_free(iter_pos->u.restore);
	87	}
	88	g_free(iter_pos);
	89	}
	90
	91	/*
	92	* seek_file_stream_by_timestamp
	93	*
	94	* Browse a filestream by index, if an index contains the timestamp passed in
	95	* argument, seek inside the corresponding packet it until we find the event we
	96	* are looking for (either the exact timestamp or the event just after the
	97	* timestamp).
	98	*
	99	* Return 0 if the seek succeded and EOF if we didn't find any packet
	100	* containing the timestamp.
	101	*/
	102	static int seek_file_stream_by_timestamp(struct ctf_file_stream *cfs,
	103	uint64_t timestamp)
	104	{
	105	struct ctf_stream_pos *stream_pos;
	106	struct packet_index *index;
	107	int i, ret;
	108
	109	stream_pos = &cfs->pos;
	110	for (i = 0; i < stream_pos->packet_index->len; i++) {
	111	index = &g_array_index(stream_pos->packet_index,
	112	struct packet_index, i);
	113	if (index->timestamp_end <= timestamp)
	114	continue;
	115
	116	stream_pos->packet_seek(&stream_pos->parent, i, SEEK_SET);
	117	while (cfs->parent.timestamp < timestamp) {
	118	ret = stream_read_event(cfs);
	119	if (ret < 0)
	120	break;
	121	}
	122	return 0;
	123	}
	124	return EOF;
	125	}
	126
	127	/*
	128	* seek_ctf_trace_by_timestamp : for each file stream, seek to the event with
	129	* the corresponding timestamp
	130	*
	131	* Return 0 on success.
	132	* If the timestamp is not part of any file stream, return EOF to inform the
	133	* user the timestamp is out of the scope
	134	*/
	135	static int seek_ctf_trace_by_timestamp(struct ctf_trace *tin,
	136	uint64_t timestamp, struct ptr_heap *stream_heap)
	137	{
	138	int i, j, ret;
	139	int found = EOF;
	140
	141	/* for each stream_class */
	142	for (i = 0; i < tin->streams->len; i++) {
	143	struct ctf_stream_class *stream_class;
	144
	145	stream_class = g_ptr_array_index(tin->streams, i);
	146	/* for each file_stream */
	147	for (j = 0; j < stream_class->streams->len; j++) {
	148	struct ctf_stream *stream;
	149	struct ctf_file_stream *cfs;
	150
	151	stream = g_ptr_array_index(stream_class->streams, j);
	152	cfs = container_of(stream, struct ctf_file_stream,
	153	parent);
	154	ret = seek_file_stream_by_timestamp(cfs, timestamp);
	155	if (ret == 0) {
	156	/* Add to heap */
	157	ret = heap_insert(stream_heap, cfs);
	158	if (ret)
	159	goto error;
	160	found = 0;
	161	}
	162	}
	163	}
	164
	165	return found;
	166
	167	error:
	168	return -2;
	169	}
	170
	171	int bt_iter_set_pos(struct bt_iter iter, const struct bt_iter_pos iter_pos)
	172	{
	173	struct trace_collection *tc;
	174	int i, ret;
	175
	176	switch (iter_pos->type) {
	177	case BT_SEEK_RESTORE:
	178	if (!iter_pos->u.restore)
	179	return -EINVAL;
	180
	181	heap_free(iter->stream_heap);
	182	ret = heap_init(iter->stream_heap, 0, stream_compare);
	183	if (ret < 0)
	184	goto error;
	185
	186	for (i = 0; i < iter_pos->u.restore->stream_saved_pos->len;
	187	i++) {
	188	struct stream_saved_pos *saved_pos;
	189	struct ctf_stream_pos *stream_pos;
	190	struct ctf_stream *stream;
	191
	192	saved_pos = &g_array_index(
	193	iter_pos->u.restore->stream_saved_pos,
	194	struct stream_saved_pos, i);
	195	stream = &saved_pos->file_stream->parent;
	196	stream_pos = &saved_pos->file_stream->pos;
	197
	198	stream_pos->packet_seek(&stream_pos->parent,
	199	saved_pos->cur_index, SEEK_SET);
	200
	201	/*
	202	* the timestamp needs to be restored after
	203	* packet_seek, because this function resets
	204	* the timestamp to the beginning of the packet
	205	*/
	206	stream->timestamp = saved_pos->current_timestamp;
	207	stream_pos->offset = saved_pos->offset;
	208	stream_pos->last_offset = saved_pos->offset;
	209
	210	stream->prev_timestamp = 0;
	211	stream->prev_timestamp_end = 0;
	212	stream->consumed = 0;
	213
	214	printf_debug("restored to cur_index = %zd and "
	215	"offset = %zd, timestamp = %" PRIu64 "\n",
	216	stream_pos->cur_index,
	217	stream_pos->offset, stream->timestamp);
	218
	219	stream_read_event(saved_pos->file_stream);
	220
	221	/* Add to heap */
	222	ret = heap_insert(iter->stream_heap,
	223	saved_pos->file_stream);
	224	if (ret)
	225	goto error;
	226	}
	227	case BT_SEEK_TIME:
	228	tc = iter->ctx->tc;
	229
	230	heap_free(iter->stream_heap);
	231	ret = heap_init(iter->stream_heap, 0, stream_compare);
	232	if (ret < 0)
	233	goto error;
	234
	235	/* for each trace in the trace_collection */
	236	for (i = 0; i < tc->array->len; i++) {
	237	struct ctf_trace *tin;
	238	struct trace_descriptor *td_read;
	239
	240	td_read = g_ptr_array_index(tc->array, i);
	241	tin = container_of(td_read, struct ctf_trace, parent);
	242
	243	ret = seek_ctf_trace_by_timestamp(tin,
	244	iter_pos->u.seek_time,
	245	iter->stream_heap);
	246	if (ret < 0)
	247	goto error;
	248	}
	249	return 0;
	250	default:
	251	/* not implemented */
	252	return -EINVAL;
	253	}
	254
	255	return 0;
	256
	257	error:
	258	heap_free(iter->stream_heap);
	259	if (heap_init(iter->stream_heap, 0, stream_compare) < 0) {
	260	heap_free(iter->stream_heap);
	261	g_free(iter->stream_heap);
	262	iter->stream_heap = NULL;
	263	ret = -ENOMEM;
	264	}
	265	return ret;
	266	}
	267
	268	struct bt_iter_pos bt_iter_get_pos(struct bt_iter iter)
	269	{
	270	struct bt_iter_pos *pos;
	271	struct trace_collection *tc = iter->ctx->tc;
	272	int i, stream_class_id, stream_id;
	273
	274	pos = g_new0(struct bt_iter_pos, 1);
	275	pos->u.restore = g_new0(struct bt_saved_pos, 1);
	276	pos->u.restore->tc = tc;
	277	pos->u.restore->stream_saved_pos = g_array_new(FALSE, TRUE,
	278	sizeof(struct stream_saved_pos));
	279	if (!pos->u.restore->stream_saved_pos)
	280	goto error;
	281
	282	for (i = 0; i < tc->array->len; i++) {
	283	struct ctf_trace *tin;
	284	struct trace_descriptor *td_read;
	285
	286	td_read = g_ptr_array_index(tc->array, i);
	287	tin = container_of(td_read, struct ctf_trace, parent);
	288
	289	for (stream_class_id = 0; stream_class_id < tin->streams->len;
	290	stream_class_id++) {
	291	struct ctf_stream_class *stream_class;
	292
	293	stream_class = g_ptr_array_index(tin->streams,
	294	stream_class_id);
	295	for (stream_id = 0;
	296	stream_id < stream_class->streams->len;
	297	stream_id++) {
	298	struct ctf_stream *stream;
	299	struct ctf_file_stream *cfs;
	300	struct stream_saved_pos saved_pos;
	301
	302	stream = g_ptr_array_index(
	303	stream_class->streams,
	304	stream_id);
	305	cfs = container_of(stream,
	306	struct ctf_file_stream,
	307	parent);
	308
	309	saved_pos.file_stream = cfs;
	310	saved_pos.cur_index = cfs->pos.cur_index;
	311
	312	/*
	313	* It is possible that an event was read during
	314	* the last restore, never consumed and its
	315	* position saved again. For this case, we
	316	* need to check if the event really was
	317	* consumed by the caller otherwise it is lost.
	318	*/
	319	if (stream->consumed)
	320	saved_pos.offset = cfs->pos.offset;
	321	else
	322	saved_pos.offset = cfs->pos.last_offset;
	323
	324	saved_pos.current_timestamp = stream->timestamp;
	325
	326	g_array_append_val(
	327	pos->u.restore->stream_saved_pos,
	328	saved_pos);
	329
	330	printf_debug("stream : %" PRIu64 ", cur_index : %zd, "
	331	"offset : %zd, "
	332	"timestamp = %" PRIu64 "\n",
	333	stream->stream_id, saved_pos.cur_index,
	334	saved_pos.offset,
	335	saved_pos.current_timestamp);
	336	}
	337	}
	338	}
	339
	340	return pos;
	341
	342	error:
	343	return NULL;
	344	}
	345
	346	struct bt_iter_pos bt_iter_create_time_pos(struct bt_iter iter,
	347	uint64_t timestamp)
	348	{
	349	struct bt_iter_pos *pos;
	350
	351	pos = g_new0(struct bt_iter_pos, 1);
	352	pos->type = BT_SEEK_TIME;
	353	pos->u.seek_time = timestamp;
	354	return pos;
	355	}
	356
	357	/*
	358	* babeltrace_filestream_seek: seek a filestream to given position.
	359	*
	360	* The stream_id parameter is only useful for BT_SEEK_RESTORE.
	361	*/
	362	static int babeltrace_filestream_seek(struct ctf_file_stream *file_stream,
	363	const struct bt_iter_pos *begin_pos,
	364	unsigned long stream_id)
	365	{
	366	int ret = 0;
	367
	368	switch (begin_pos->type) {
	369	case BT_SEEK_CUR:
	370	/*
	371	* just insert into the heap we should already know
	372	* the timestamps
	373	*/
	374	break;
	375	case BT_SEEK_BEGIN:
	376	file_stream->pos.packet_seek(&file_stream->pos.parent,
	377	0, SEEK_SET);
	378	ret = stream_read_event(file_stream);
	379	break;
	380	case BT_SEEK_TIME:
	381	case BT_SEEK_RESTORE:
	382	case BT_SEEK_END:
	383	default:
	384	assert(0); /* Not yet defined */
	385	}
	386
	387	return ret;
	388	}
	389
	390	/*
	391	* bt_iter_seek: seek iterator to given position.
	392	*/
	393	int bt_iter_seek(struct bt_iter *iter,
	394	const struct bt_iter_pos *begin_pos)
	395	{
	396	int i, stream_id;
	397	int ret = 0;
	398	struct trace_collection *tc = iter->ctx->tc;
	399
	400	for (i = 0; i < tc->array->len; i++) {
	401	struct ctf_trace *tin;
	402	struct trace_descriptor *td_read;
	403
	404	td_read = g_ptr_array_index(tc->array, i);
	405	tin = container_of(td_read, struct ctf_trace, parent);
	406
	407	/* Populate heap with each stream */
	408	for (stream_id = 0; stream_id < tin->streams->len;
	409	stream_id++) {
	410	struct ctf_stream_class *stream;
	411	int filenr;
	412
	413	stream = g_ptr_array_index(tin->streams, stream_id);
	414	for (filenr = 0; filenr < stream->streams->len;
	415	filenr++) {
	416	struct ctf_file_stream *file_stream;
	417
	418	file_stream = g_ptr_array_index(stream->streams,
	419	filenr);
	420	ret = babeltrace_filestream_seek(file_stream, begin_pos,
	421	stream_id);
	422	if (ret < 0)
	423	goto end;
	424	}
	425	}
	426	}
	427	end:
	428	return ret;
	429	}
	430
	431	int bt_iter_init(struct bt_iter *iter,
	432	struct bt_context *ctx,
	433	const struct bt_iter_pos *begin_pos,
	434	const struct bt_iter_pos *end_pos)
	435	{
	436	int i, stream_id;
	437	int ret = 0;
	438
	439	iter->stream_heap = g_new(struct ptr_heap, 1);
	440	iter->end_pos = end_pos;
	441	bt_context_get(ctx);
	442	iter->ctx = ctx;
	443
	444	ret = heap_init(iter->stream_heap, 0, stream_compare);
	445	if (ret < 0)
	446	goto error_heap_init;
	447
	448	for (i = 0; i < ctx->tc->array->len; i++) {
	449	struct ctf_trace *tin;
	450	struct trace_descriptor *td_read;
	451
	452	td_read = g_ptr_array_index(ctx->tc->array, i);
	453	tin = container_of(td_read, struct ctf_trace, parent);
	454
	455	/* Populate heap with each stream */
	456	for (stream_id = 0; stream_id < tin->streams->len;
	457	stream_id++) {
	458	struct ctf_stream_class *stream;
	459	int filenr;
	460
	461	stream = g_ptr_array_index(tin->streams, stream_id);
	462	if (!stream)
	463	continue;
	464	for (filenr = 0; filenr < stream->streams->len;
	465	filenr++) {
	466	struct ctf_file_stream *file_stream;
	467
	468	file_stream = g_ptr_array_index(stream->streams,
	469	filenr);
	470
	471	if (begin_pos) {
	472	ret = babeltrace_filestream_seek(file_stream, begin_pos,
	473	stream_id);
	474	if (ret == EOF) {
	475	ret = 0;
	476	continue;
	477	} else if (ret) {
	478	goto error;
	479	}
	480	}
	481	/* Add to heap */
	482	ret = heap_insert(iter->stream_heap, file_stream);
	483	if (ret)
	484	goto error;
	485	}
	486	}
	487	}
	488
	489	return 0;
	490
	491	error:
	492	heap_free(iter->stream_heap);
	493	error_heap_init:
	494	g_free(iter->stream_heap);
	495	return ret;
	496	}
	497
	498	struct bt_iter bt_iter_create(struct bt_context ctx,
	499	const struct bt_iter_pos *begin_pos,
	500	const struct bt_iter_pos *end_pos)
	501	{
	502	struct bt_iter *iter;
	503	int ret;
	504
	505	iter = g_new0(struct bt_iter, 1);
	506	ret = bt_iter_init(iter, ctx, begin_pos, end_pos);
	507	if (ret) {
	508	g_free(iter);
	509	return NULL;
	510	}
	511	return iter;
	512	}
	513
	514	void bt_iter_fini(struct bt_iter *iter)
	515	{
	516	if (iter->stream_heap) {
	517	heap_free(iter->stream_heap);
	518	g_free(iter->stream_heap);
	519	}
	520	bt_context_put(iter->ctx);
	521	}
	522
	523	void bt_iter_destroy(struct bt_iter *iter)
	524	{
	525	bt_iter_fini(iter);
	526	g_free(iter);
	527	}
	528
	529	int bt_iter_next(struct bt_iter *iter)
	530	{
	531	struct ctf_file_stream file_stream, removed;
	532	int ret;
	533
	534	file_stream = heap_maximum(iter->stream_heap);
	535	if (!file_stream) {
	536	/* end of file for all streams */
	537	ret = 0;
	538	goto end;
	539	}
	540
	541	ret = stream_read_event(file_stream);
	542	if (ret == EOF) {
	543	removed = heap_remove(iter->stream_heap);
	544	assert(removed == file_stream);
	545	ret = 0;
	546	goto end;
	547	} else if (ret) {
	548	goto end;
	549	}
	550	/* Reinsert the file stream into the heap, and rebalance. */
	551	removed = heap_replace_max(iter->stream_heap, file_stream);
	552	assert(removed == file_stream);
	553
	554	end:
	555	return ret;
	556	}