X-Git-Url: https://sigrok.org/gitweb/?a=blobdiff_plain;f=src%2Fsession.c;h=44aa59ed729afb4c101d29957b931ca4b78f8e64;hb=5a7d8dac9042e5db6f2e058f20d7344ad322d17a;hp=dc8fd4fbeaffc2ce3c78cdeabcd5156f30c44363;hpb=013ec84b83a64088b524bb0b3a923c98b7ae9ea4;p=libsigrok.git

diff --git a/src/session.c b/src/session.c
index dc8fd4fb..44aa59ed 100644
--- a/src/session.c
+++ b/src/session.c
@@ -17,12 +17,13 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <string.h>
 #include <glib.h>
-#include "libsigrok.h"
+#include <libsigrok/libsigrok.h>
 #include "libsigrok-internal.h"
 
 /** @cond PRIVATE */
@@ -44,7 +45,9 @@
  */
 
 struct source {
-	int timeout;
+	int64_t timeout;	/* microseconds */
+	int64_t due;		/* microseconds */
+
 	sr_receive_data_callback cb;
 	void *cb_data;
 
@@ -52,6 +55,14 @@ struct source {
 	 * being polled and will be used to match the source when removing it again.
 	 */
 	gintptr poll_object;
+
+	/* Number of fds to poll for this source. This will be 0 for timer
+	 * sources, 1 for normal I/O sources, and 1 or more for libusb I/O
+	 * sources on Unix platforms.
+	 */
+	int num_fds;
+
+	gboolean triggered;
 };
 
 struct datafeed_callback {
@@ -62,6 +73,7 @@ struct datafeed_callback {
 /**
  * Create a new session.
  *
+ * @param ctx         The context in which to create the new session.
  * @param new_session This will contain a pointer to the newly created
  *                    session if the return value is SR_OK, otherwise the value
  *                    is undefined and should not be used. Must not be NULL.
@@ -71,7 +83,8 @@ struct datafeed_callback {
  *
  * @since 0.4.0
  */
-SR_API int sr_session_new(struct sr_session **new_session)
+SR_API int sr_session_new(struct sr_context *ctx,
+		struct sr_session **new_session)
 {
 	struct sr_session *session;
 
@@ -80,9 +93,11 @@ SR_API int sr_session_new(struct sr_session **new_session)
 
 	session = g_malloc0(sizeof(struct sr_session));
 
-	session->source_timeout = -1;
-	session->running = FALSE;
-	session->abort_session = FALSE;
+	session->ctx = ctx;
+
+	session->sources = g_array_new(FALSE, FALSE, sizeof(struct source));
+	session->pollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD));
+
 	g_mutex_init(&session->stop_mutex);
 
 	*new_session = session;
@@ -113,6 +128,11 @@ SR_API int sr_session_destroy(struct sr_session *session)
 	if (session->trigger)
 		sr_trigger_free(session->trigger);
 
+	g_slist_free_full(session->owned_devs, (GDestroyNotify)sr_dev_inst_free);
+
+	g_array_unref(session->pollfds);
+	g_array_unref(session->sources);
+
 	g_free(session);
 
 	return SR_OK;
@@ -304,9 +324,7 @@ SR_API int sr_session_datafeed_callback_add(struct sr_session *session,
 		return SR_ERR_ARG;
 	}
 
-	if (!(cb_struct = g_try_malloc0(sizeof(struct datafeed_callback))))
-		return SR_ERR_MALLOC;
-
+	cb_struct = g_malloc0(sizeof(struct datafeed_callback));
 	cb_struct->cb = cb;
 	cb_struct->cb_data = cb_data;
 
@@ -316,76 +334,219 @@ SR_API int sr_session_datafeed_callback_add(struct sr_session *session,
 	return SR_OK;
 }
 
+/**
+ * Get the trigger assigned to this session.
+ *
+ * @param session The session to use.
+ *
+ * @retval NULL Invalid (NULL) session was passed to the function.
+ * @retval other The trigger assigned to this session (can be NULL).
+ *
+ * @since 0.4.0
+ */
 SR_API struct sr_trigger *sr_session_trigger_get(struct sr_session *session)
 {
+	if (!session)
+		return NULL;
+
 	return session->trigger;
 }
 
+/**
+ * Set the trigger of this session.
+ *
+ * @param session The session to use. Must not be NULL.
+ * @param trig The trigger to assign to this session. Can be NULL.
+ *
+ * @retval SR_OK Success.
+ * @retval SR_ERR_ARG Invalid argument.
+ *
+ * @since 0.4.0
+ */
 SR_API int sr_session_trigger_set(struct sr_session *session, struct sr_trigger *trig)
 {
+	if (!session)
+		return SR_ERR_ARG;
+
 	session->trigger = trig;
 
 	return SR_OK;
 }
 
+static gboolean sr_session_check_aborted(struct sr_session *session)
+{
+	gboolean stop;
+
+	g_mutex_lock(&session->stop_mutex);
+	stop = session->abort_session;
+	if (stop) {
+		sr_session_stop_sync(session);
+		/* But once is enough. */
+		session->abort_session = FALSE;
+	}
+	g_mutex_unlock(&session->stop_mutex);
+
+	return stop;
+}
+
 /**
- * Call every device in the current session's callback.
- *
- * For sessions not driven by select loops such as sr_session_run(),
- * but driven by another scheduler, this can be used to poll the devices
- * from within that scheduler.
+ * Poll the session's event sources.
  *
  * @param session The session to use. Must not be NULL.
- * @param block If TRUE, this call will wait for any of the session's
- *              sources to fire an event on the file descriptors, or
- *              any of their timeouts to activate. In other words, this
- *              can be used as a select loop.
- *              If FALSE, all sources have their callback run, regardless
- *              of file descriptor or timeout status.
- *
  * @retval SR_OK Success.
- * @retval SR_ERR Error occured.
+ * @retval SR_ERR Error occurred.
  */
-static int sr_session_iteration(struct sr_session *session, gboolean block)
+static int sr_session_iteration(struct sr_session *session)
 {
+	int64_t start_time, stop_time, min_due, due;
+	int timeout_ms;
 	unsigned int i;
+	int k, fd_index;
 	int ret;
+	int fd;
+	int revents;
+	gboolean triggered, stopped;
+	struct source *source;
+	GPollFD *pollfd;
+	gintptr poll_object;
+#if HAVE_LIBUSB_1_0 && !defined(G_OS_WIN32)
+	int64_t usb_timeout;
+	int64_t usb_due;
+	struct timeval tv;
+#endif
+	if (session->sources->len == 0) {
+		sr_session_check_aborted(session);
+		return SR_OK;
+	}
+	start_time = g_get_monotonic_time();
+	min_due = INT64_MAX;
+
+	for (i = 0; i < session->sources->len; ++i) {
+		source = &g_array_index(session->sources, struct source, i);
+		if (source->due < min_due)
+			min_due = source->due;
+		source->triggered = FALSE;
+	}
+#if HAVE_LIBUSB_1_0 && !defined(G_OS_WIN32)
+	usb_due = INT64_MAX;
+	if (session->ctx->usb_source_present) {
+		ret = libusb_get_next_timeout(session->ctx->libusb_ctx, &tv);
+		if (ret < 0) {
+			sr_err("Error getting libusb timeout: %s",
+				libusb_error_name(ret));
+			return SR_ERR;
+		} else if (ret == 1) {
+			usb_timeout = (int64_t)tv.tv_sec * G_USEC_PER_SEC
+					+ tv.tv_usec;
+			usb_due = start_time + usb_timeout;
+			if (usb_due < min_due)
+				min_due = usb_due;
+
+			sr_spew("poll: next USB timeout %g ms",
+				1e-3 * usb_timeout);
+		}
+	}
+#endif
+	if (min_due == INT64_MAX)
+		timeout_ms = -1;
+	else if (min_due > start_time)
+		timeout_ms = MIN((min_due - start_time + 999) / 1000, INT_MAX);
+	else
+		timeout_ms = 0;
+
+	sr_spew("poll enter: %u sources, %u fds, %d ms timeout",
+		session->sources->len, session->pollfds->len, timeout_ms);
+
+	ret = g_poll((GPollFD *)session->pollfds->data,
+			session->pollfds->len, timeout_ms);
+#ifdef G_OS_UNIX
+	if (ret < 0 && errno != EINTR) {
+		sr_err("Error in poll: %s", g_strerror(errno));
+		return SR_ERR;
+	}
+#else
+	if (ret < 0) {
+		sr_err("Error in poll: %d", ret);
+		return SR_ERR;
+	}
+#endif
+	stop_time = g_get_monotonic_time();
 
-	ret = g_poll(session->pollfds, session->num_sources,
-			block ? session->source_timeout : 0);
-	for (i = 0; i < session->num_sources; i++) {
-		if (session->pollfds[i].revents > 0 || (ret == 0
-			&& session->source_timeout == session->sources[i].timeout)) {
-			/*
-			 * Invoke the source's callback on an event,
-			 * or if the poll timed out and this source
-			 * asked for that timeout.
-			 */
-			if (!session->sources[i].cb(session->pollfds[i].fd,
-					session->pollfds[i].revents,
-					session->sources[i].cb_data))
-				sr_session_source_remove(session,
-						session->sources[i].poll_object);
+	sr_spew("poll leave: %g ms elapsed, %d events",
+		1e-3 * (stop_time - start_time), ret);
+
+	triggered = FALSE;
+	stopped = FALSE;
+	fd_index = 0;
+
+	for (i = 0; i < session->sources->len; ++i) {
+		source = &g_array_index(session->sources, struct source, i);
+
+		poll_object = source->poll_object;
+		fd = (int)poll_object;
+		revents = 0;
+
+		for (k = 0; k < source->num_fds; ++k) {
+			pollfd = &g_array_index(session->pollfds,
+					GPollFD, fd_index + k);
+			fd = pollfd->fd;
+			revents |= pollfd->revents;
 		}
+		fd_index += source->num_fds;
+
+		if (source->triggered)
+			continue; /* already handled */
+		if (ret > 0 && revents == 0)
+			continue; /* skip timeouts if any I/O event occurred */
+
+		/* Make invalid to avoid confusion in case of multiple FDs. */
+		if (source->num_fds > 1)
+			fd = -1;
+		if (ret <= 0)
+			revents = 0;
+
+		due = source->due;
+#if HAVE_LIBUSB_1_0 && !defined(G_OS_WIN32)
+		if (usb_due < due && poll_object
+				== (gintptr)session->ctx->libusb_ctx)
+			due = usb_due;
+#endif
+		if (revents == 0 && stop_time < due)
+			continue;
+		/*
+		 * The source may be gone after the callback returns,
+		 * so access any data now that needs accessing.
+		 */
+		if (source->timeout >= 0)
+			source->due = stop_time + source->timeout;
+		source->triggered = TRUE;
+		triggered = TRUE;
+		/*
+		 * Invoke the source's callback on an event or timeout.
+		 */
+		if (!source->cb(fd, revents, source->cb_data))
+			sr_session_source_remove_internal(session, poll_object);
 		/*
 		 * We want to take as little time as possible to stop
 		 * the session if we have been told to do so. Therefore,
 		 * we check the flag after processing every source, not
 		 * just once per main event loop.
 		 */
-		g_mutex_lock(&session->stop_mutex);
-		if (session->abort_session) {
-			sr_session_stop_sync(session);
-			/* But once is enough. */
-			session->abort_session = FALSE;
-		}
-		g_mutex_unlock(&session->stop_mutex);
+		if (!stopped)
+			stopped = sr_session_check_aborted(session);
+
+		/* Restart loop as the sources list may have changed. */
+		fd_index = 0;
+		i = 0;
 	}
 
+	/* Check for abort at least once per iteration. */
+	if (!triggered)
+		sr_session_check_aborted(session);
+
 	return SR_OK;
 }
 
-
 static int verify_trigger(struct sr_trigger *trigger)
 {
 	struct sr_trigger_stage *stage;
@@ -421,6 +582,7 @@ static int verify_trigger(struct sr_trigger *trigger)
 
 	return SR_OK;
 }
+
 /**
  * Start a session.
  *
@@ -467,8 +629,8 @@ SR_API int sr_session_start(struct sr_session *session)
 		}
 		if (enabled_channels == 0) {
 			ret = SR_ERR;
-			sr_err("%s instance %d has no enabled channels!",
-					sdi->driver->name, sdi->index);
+			sr_err("%s using connection %s has no enabled channels!",
+					sdi->driver->name, sdi->connection_id);
 			break;
 		}
 
@@ -496,11 +658,14 @@ SR_API int sr_session_start(struct sr_session *session)
  *
  * @retval SR_OK Success.
  * @retval SR_ERR_ARG Invalid session passed.
+ * @retval SR_ERR Error during event processing.
  *
  * @since 0.4.0
  */
 SR_API int sr_session_run(struct sr_session *session)
 {
+	int ret;
+
 	if (!session) {
 		sr_err("%s: session was NULL", __func__);
 		return SR_ERR_ARG;
@@ -516,17 +681,12 @@ SR_API int sr_session_run(struct sr_session *session)
 
 	sr_info("Running.");
 
-	/* Do we have real sources? */
-	if (session->num_sources == 1 && session->pollfds[0].fd == -1) {
-		/* Dummy source, freewheel over it. */
-		while (session->num_sources)
-			session->sources[0].cb(-1, 0, session->sources[0].cb_data);
-	} else {
-		/* Real sources, use g_poll() main loop. */
-		while (session->num_sources)
-			sr_session_iteration(session, TRUE);
+	/* Poll event sources until none are left. */
+	while (session->sources->len > 0) {
+		ret = sr_session_iteration(session);
+		if (ret != SR_OK)
+			return ret;
 	}
-
 	return SR_OK;
 }
 
@@ -611,17 +771,22 @@ static void datafeed_dump(const struct sr_datafeed_packet *packet)
 {
 	const struct sr_datafeed_logic *logic;
 	const struct sr_datafeed_analog *analog;
+	const struct sr_datafeed_analog2 *analog2;
 
+	/* Please use the same order as in libsigrok.h. */
 	switch (packet->type) {
 	case SR_DF_HEADER:
 		sr_dbg("bus: Received SR_DF_HEADER packet.");
 		break;
-	case SR_DF_TRIGGER:
-		sr_dbg("bus: Received SR_DF_TRIGGER packet.");
+	case SR_DF_END:
+		sr_dbg("bus: Received SR_DF_END packet.");
 		break;
 	case SR_DF_META:
 		sr_dbg("bus: Received SR_DF_META packet.");
 		break;
+	case SR_DF_TRIGGER:
+		sr_dbg("bus: Received SR_DF_TRIGGER packet.");
+		break;
 	case SR_DF_LOGIC:
 		logic = packet->payload;
 		sr_dbg("bus: Received SR_DF_LOGIC packet (%" PRIu64 " bytes, "
@@ -632,15 +797,17 @@ static void datafeed_dump(const struct sr_datafeed_packet *packet)
 		sr_dbg("bus: Received SR_DF_ANALOG packet (%d samples).",
 		       analog->num_samples);
 		break;
-	case SR_DF_END:
-		sr_dbg("bus: Received SR_DF_END packet.");
-		break;
 	case SR_DF_FRAME_BEGIN:
 		sr_dbg("bus: Received SR_DF_FRAME_BEGIN packet.");
 		break;
 	case SR_DF_FRAME_END:
 		sr_dbg("bus: Received SR_DF_FRAME_END packet.");
 		break;
+	case SR_DF_ANALOG2:
+		analog2 = packet->payload;
+		sr_dbg("bus: Received SR_DF_ANALOG2 packet (%d samples).",
+		       analog2->num_samples);
+		break;
 	default:
 		sr_dbg("bus: Received unknown packet type: %d.", packet->type);
 		break;
@@ -661,10 +828,13 @@ static void datafeed_dump(const struct sr_datafeed_packet *packet)
  * @private
  */
 SR_PRIV int sr_session_send(const struct sr_dev_inst *sdi,
-			    const struct sr_datafeed_packet *packet)
+		const struct sr_datafeed_packet *packet)
 {
 	GSList *l;
 	struct datafeed_callback *cb_struct;
+	struct sr_datafeed_packet *packet_in, *packet_out;
+	struct sr_transform *t;
+	int ret;
 
 	if (!sdi) {
 		sr_err("%s: sdi was NULL", __func__);
@@ -676,6 +846,46 @@ SR_PRIV int sr_session_send(const struct sr_dev_inst *sdi,
 		return SR_ERR_ARG;
 	}
 
+	if (!sdi->session) {
+		sr_err("%s: session was NULL", __func__);
+		return SR_ERR_BUG;
+	}
+
+	/*
+	 * Pass the packet to the first transform module. If that returns
+	 * another packet (instead of NULL), pass that packet to the next
+	 * transform module in the list, and so on.
+	 */
+	packet_in = (struct sr_datafeed_packet *)packet;
+	for (l = sdi->session->transforms; l; l = l->next) {
+		t = l->data;
+		sr_spew("Running transform module '%s'.", t->module->id);
+		ret = t->module->receive(t, packet_in, &packet_out);
+		if (ret < 0) {
+			sr_err("Error while running transform module: %d.", ret);
+			return SR_ERR;
+		}
+		if (!packet_out) {
+			/*
+			 * If any of the transforms don't return an output
+			 * packet, abort.
+			 */
+			sr_spew("Transform module didn't return a packet, aborting.");
+			return SR_OK;
+		} else {
+			/*
+			 * Use this transform module's output packet as input
+			 * for the next transform module.
+			 */
+			packet_in = packet_out;
+		}
+	}
+	packet = packet_in;
+
+	/*
+	 * If the last transform did output a packet, pass it to all datafeed
+	 * callbacks.
+	 */
 	for (l = sdi->session->datafeed_callbacks; l; l = l->next) {
 		if (sr_log_loglevel_get() >= SR_LOG_DBG)
 			datafeed_dump(packet);
@@ -690,56 +900,62 @@ SR_PRIV int sr_session_send(const struct sr_dev_inst *sdi,
  * Add an event source for a file descriptor.
  *
  * @param session The session to use. Must not be NULL.
- * @param pollfd The GPollFD.
- * @param[in] timeout Max time to wait before the callback is called,
- *              ignored if 0.
+ * @param[in] pollfds The FDs to poll, or NULL if @a num_fds is 0.
+ * @param[in] num_fds Number of FDs in the array.
+ * @param[in] timeout Max time in ms to wait before the callback is called,
+ *                    or -1 to wait indefinitely.
  * @param cb Callback function to add. Must not be NULL.
  * @param cb_data Data for the callback function. Can be NULL.
- * @param poll_object TODO.
+ * @param poll_object Handle by which the source is identified
  *
  * @retval SR_OK Success.
  * @retval SR_ERR_ARG Invalid argument.
- * @retval SR_ERR_MALLOC Memory allocation error.
+ * @retval SR_ERR An event source for @a poll_object is already installed.
  */
-static int _sr_session_source_add(struct sr_session *session, GPollFD *pollfd,
-		int timeout, sr_receive_data_callback cb, void *cb_data, gintptr poll_object)
+SR_PRIV int sr_session_source_add_internal(struct sr_session *session,
+		const GPollFD *pollfds, int num_fds, int timeout,
+		sr_receive_data_callback cb, void *cb_data,
+		gintptr poll_object)
 {
-	struct source *new_sources, *s;
-	GPollFD *new_pollfds;
+	struct source src;
+	unsigned int i;
 
+	/* Note: cb_data can be NULL, that's not a bug. */
 	if (!cb) {
 		sr_err("%s: cb was NULL", __func__);
 		return SR_ERR_ARG;
 	}
-
-	/* Note: cb_data can be NULL, that's not a bug. */
-
-	new_pollfds = g_try_realloc(session->pollfds,
-			sizeof(GPollFD) * (session->num_sources + 1));
-	if (!new_pollfds) {
-		sr_err("%s: new_pollfds malloc failed", __func__);
-		return SR_ERR_MALLOC;
+	if (!pollfds && num_fds != 0) {
+		sr_err("%s: pollfds was NULL", __func__);
+		return SR_ERR_ARG;
 	}
-
-	new_sources = g_try_realloc(session->sources, sizeof(struct source) *
-			(session->num_sources + 1));
-	if (!new_sources) {
-		sr_err("%s: new_sources malloc failed", __func__);
-		return SR_ERR_MALLOC;
+	/* Make sure that poll_object is unique.
+	 */
+	for (i = 0; i < session->sources->len; ++i) {
+		if (g_array_index(session->sources, struct source, i)
+				.poll_object == poll_object) {
+			sr_err("Event source for object %" G_GINTPTR_FORMAT
+				" already installed.", poll_object);
+			return SR_ERR;
+		}
 	}
+	src.cb = cb;
+	src.cb_data = cb_data;
+	src.poll_object = poll_object;
+	src.num_fds = num_fds;
+	src.triggered = FALSE;
+
+	if (timeout >= 0) {
+		src.timeout = INT64_C(1000) * timeout;
+		src.due = g_get_monotonic_time() + src.timeout;
+	} else {
+		src.timeout = -1;
+		src.due = INT64_MAX;
+	}
+	g_array_append_val(session->sources, src);
 
-	new_pollfds[session->num_sources] = *pollfd;
-	s = &new_sources[session->num_sources++];
-	s->timeout = timeout;
-	s->cb = cb;
-	s->cb_data = cb_data;
-	s->poll_object = poll_object;
-	session->pollfds = new_pollfds;
-	session->sources = new_sources;
-
-	if (timeout != session->source_timeout && timeout > 0
-	    && (session->source_timeout == -1 || timeout < session->source_timeout))
-		session->source_timeout = timeout;
+	if (num_fds > 0)
+		g_array_append_vals(session->pollfds, pollfds, num_fds);
 
 	return SR_OK;
 }
@@ -750,13 +966,13 @@ static int _sr_session_source_add(struct sr_session *session, GPollFD *pollfd,
  * @param session The session to use. Must not be NULL.
  * @param fd The file descriptor.
  * @param events Events to check for.
- * @param timeout Max time to wait before the callback is called, ignored if 0.
+ * @param timeout Max time in ms to wait before the callback is called,
+ *                or -1 to wait indefinitely.
  * @param cb Callback function to add. Must not be NULL.
  * @param cb_data Data for the callback function. Can be NULL.
  *
  * @retval SR_OK Success.
  * @retval SR_ERR_ARG Invalid argument.
- * @retval SR_ERR_MALLOC Memory allocation error.
  *
  * @since 0.3.0
  */
@@ -765,24 +981,30 @@ SR_API int sr_session_source_add(struct sr_session *session, int fd,
 {
 	GPollFD p;
 
+	if (fd < 0 && timeout < 0) {
+		sr_err("Timer source without timeout would block indefinitely");
+		return SR_ERR_ARG;
+	}
 	p.fd = fd;
 	p.events = events;
+	p.revents = 0;
 
-	return _sr_session_source_add(session, &p, timeout, cb, cb_data, (gintptr)fd);
+	return sr_session_source_add_internal(session,
+		&p, (fd < 0) ? 0 : 1, timeout, cb, cb_data, fd);
 }
 
 /**
  * Add an event source for a GPollFD.
  *
  * @param session The session to use. Must not be NULL.
- * @param pollfd The GPollFD.
- * @param timeout Max time to wait before the callback is called, ignored if 0.
+ * @param pollfd The GPollFD. Must not be NULL.
+ * @param timeout Max time in ms to wait before the callback is called,
+ *                or -1 to wait indefinitely.
  * @param cb Callback function to add. Must not be NULL.
  * @param cb_data Data for the callback function. Can be NULL.
  *
  * @retval SR_OK Success.
  * @retval SR_ERR_ARG Invalid argument.
- * @retval SR_ERR_MALLOC Memory allocation error.
  *
  * @since 0.3.0
  */
@@ -790,8 +1012,12 @@ SR_API int sr_session_source_add_pollfd(struct sr_session *session,
 		GPollFD *pollfd, int timeout, sr_receive_data_callback cb,
 		void *cb_data)
 {
-	return _sr_session_source_add(session, pollfd, timeout, cb,
-				      cb_data, (gintptr)pollfd);
+	if (!pollfd) {
+		sr_err("%s: pollfd was NULL", __func__);
+		return SR_ERR_ARG;
+	}
+	return sr_session_source_add_internal(session, pollfd, 1,
+			timeout, cb, cb_data, (gintptr)pollfd);
 }
 
 /**
@@ -800,13 +1026,13 @@ SR_API int sr_session_source_add_pollfd(struct sr_session *session,
  * @param session The session to use. Must not be NULL.
  * @param channel The GIOChannel.
  * @param events Events to poll on.
- * @param timeout Max time to wait before the callback is called, ignored if 0.
+ * @param timeout Max time in ms to wait before the callback is called,
+ *                or -1 to wait indefinitely.
  * @param cb Callback function to add. Must not be NULL.
  * @param cb_data Data for the callback function. Can be NULL.
  *
  * @retval SR_OK Success.
  * @retval SR_ERR_ARG Invalid argument.
- * @retval SR_ERR_MALLOC Memory allocation error.
  *
  * @since 0.3.0
  */
@@ -816,74 +1042,58 @@ SR_API int sr_session_source_add_channel(struct sr_session *session,
 {
 	GPollFD p;
 
-#ifdef _WIN32
+#ifdef G_OS_WIN32
 	g_io_channel_win32_make_pollfd(channel, events, &p);
 #else
 	p.fd = g_io_channel_unix_get_fd(channel);
 	p.events = events;
+	p.revents = 0;
 #endif
-
-	return _sr_session_source_add(session, &p, timeout, cb, cb_data, (gintptr)channel);
+	return sr_session_source_add_internal(session, &p, 1,
+			timeout, cb, cb_data, (gintptr)channel);
 }
 
 /**
- * Remove the source belonging to the specified channel.
- *
- * @todo Add more error checks and logging.
+ * Remove the source identified by the specified poll object.
  *
  * @param session The session to use. Must not be NULL.
  * @param poll_object The channel for which the source should be removed.
  *
  * @retval SR_OK Success
- * @retval SR_ERR_ARG Invalid arguments
- * @retval SR_ERR_MALLOC Memory allocation error
- * @retval SR_ERR_BUG Internal error
+ * @retval SR_ERR_BUG No event source for poll_object found.
  */
-static int _sr_session_source_remove(struct sr_session *session, gintptr poll_object)
+SR_PRIV int sr_session_source_remove_internal(struct sr_session *session,
+		gintptr poll_object)
 {
-	struct source *new_sources;
-	GPollFD *new_pollfds;
-	unsigned int old;
-
-	if (!session->sources || !session->num_sources) {
-		sr_err("%s: sources was NULL", __func__);
-		return SR_ERR_BUG;
-	}
-
-	for (old = 0; old < session->num_sources; old++) {
-		if (session->sources[old].poll_object == poll_object)
-			break;
-	}
-
-	/* fd not found, nothing to do */
-	if (old == session->num_sources)
-		return SR_OK;
-
-	session->num_sources -= 1;
-
-	if (old != session->num_sources) {
-		memmove(&session->pollfds[old], &session->pollfds[old+1],
-			(session->num_sources - old) * sizeof(GPollFD));
-		memmove(&session->sources[old], &session->sources[old+1],
-			(session->num_sources - old) * sizeof(struct source));
-	}
+	struct source *source;
+	unsigned int i;
+	int fd_index = 0;
 
-	new_pollfds = g_try_realloc(session->pollfds, sizeof(GPollFD) * session->num_sources);
-	if (!new_pollfds && session->num_sources > 0) {
-		sr_err("%s: new_pollfds malloc failed", __func__);
-		return SR_ERR_MALLOC;
-	}
+	for (i = 0; i < session->sources->len; ++i) {
+		source = &g_array_index(session->sources, struct source, i);
 
-	new_sources = g_try_realloc(session->sources, sizeof(struct source) * session->num_sources);
-	if (!new_sources && session->num_sources > 0) {
-		sr_err("%s: new_sources malloc failed", __func__);
-		return SR_ERR_MALLOC;
+		if (source->poll_object == poll_object) {
+			if (source->num_fds > 0)
+				g_array_remove_range(session->pollfds,
+						fd_index, source->num_fds);
+			g_array_remove_index(session->sources, i);
+			/*
+			 * This is a bit of a hack. To be removed when
+			 * porting over to the GLib main loop.
+			 */
+			if (poll_object == (gintptr)session->ctx->libusb_ctx)
+				session->ctx->usb_source_present = FALSE;
+			return SR_OK;
+		}
+		fd_index += source->num_fds;
 	}
+	/* Trying to remove an already removed event source is problematic
+	 * since the poll_object handle may have been reused in the meantime.
+	 */
+	sr_warn("Cannot remove non-existing event source for object %"
+		G_GINTPTR_FORMAT ".", poll_object);
 
-	session->pollfds = new_pollfds;
-	session->sources = new_sources;
-
-	return SR_OK;
+	return SR_ERR_BUG;
 }
 
 /**
@@ -894,14 +1104,13 @@ static int _sr_session_source_remove(struct sr_session *session, gintptr poll_ob
  *
  * @retval SR_OK Success
  * @retval SR_ERR_ARG Invalid argument
- * @retval SR_ERR_MALLOC Memory allocation error.
  * @retval SR_ERR_BUG Internal error.
  *
  * @since 0.3.0
  */
 SR_API int sr_session_source_remove(struct sr_session *session, int fd)
 {
-	return _sr_session_source_remove(session, (gintptr)fd);
+	return sr_session_source_remove_internal(session, fd);
 }
 
 /**
@@ -909,7 +1118,7 @@ SR_API int sr_session_source_remove(struct sr_session *session, int fd)
  *
  * @param session The session to use. Must not be NULL.
  * @param pollfd The poll descriptor for which the source should be removed.
- *
+ *               Must not be NULL.
  * @return SR_OK upon success, SR_ERR_ARG upon invalid arguments, or
  *         SR_ERR_MALLOC upon memory allocation errors, SR_ERR_BUG upon
  *         internal errors.
@@ -919,7 +1128,11 @@ SR_API int sr_session_source_remove(struct sr_session *session, int fd)
 SR_API int sr_session_source_remove_pollfd(struct sr_session *session,
 		GPollFD *pollfd)
 {
-	return _sr_session_source_remove(session, (gintptr)pollfd);
+	if (!pollfd) {
+		sr_err("%s: pollfd was NULL", __func__);
+		return SR_ERR_ARG;
+	}
+	return sr_session_source_remove_internal(session, (gintptr)pollfd);
 }
 
 /**
@@ -927,10 +1140,9 @@ SR_API int sr_session_source_remove_pollfd(struct sr_session *session,
  *
  * @param session The session to use. Must not be NULL.
  * @param channel The channel for which the source should be removed.
- *
+ *                Must not be NULL.
  * @retval SR_OK Success.
  * @retval SR_ERR_ARG Invalid argument.
- * @retval SR_ERR_MALLOC Memory allocation error.
  * @return SR_ERR_BUG Internal error.
  *
  * @since 0.2.0
@@ -938,7 +1150,121 @@ SR_API int sr_session_source_remove_pollfd(struct sr_session *session,
 SR_API int sr_session_source_remove_channel(struct sr_session *session,
 		GIOChannel *channel)
 {
-	return _sr_session_source_remove(session, (gintptr)channel);
+	if (!channel) {
+		sr_err("%s: channel was NULL", __func__);
+		return SR_ERR_ARG;
+	}
+	return sr_session_source_remove_internal(session, (gintptr)channel);
+}
+
+static void copy_src(struct sr_config *src, struct sr_datafeed_meta *meta_copy)
+{
+	g_variant_ref(src->data);
+	meta_copy->config = g_slist_append(meta_copy->config,
+	                                   g_memdup(src, sizeof(struct sr_config)));
+}
+
+SR_PRIV int sr_packet_copy(const struct sr_datafeed_packet *packet,
+		struct sr_datafeed_packet **copy)
+{
+	const struct sr_datafeed_meta *meta;
+	struct sr_datafeed_meta *meta_copy;
+	const struct sr_datafeed_logic *logic;
+	struct sr_datafeed_logic *logic_copy;
+	const struct sr_datafeed_analog *analog;
+	struct sr_datafeed_analog *analog_copy;
+	uint8_t *payload;
+
+	*copy = g_malloc0(sizeof(struct sr_datafeed_packet));
+	(*copy)->type = packet->type;
+
+	switch (packet->type) {
+	case SR_DF_TRIGGER:
+	case SR_DF_END:
+		/* No payload. */
+		break;
+	case SR_DF_HEADER:
+		payload = g_malloc(sizeof(struct sr_datafeed_header));
+		memcpy(payload, packet->payload, sizeof(struct sr_datafeed_header));
+		(*copy)->payload = payload;
+		break;
+	case SR_DF_META:
+		meta = packet->payload;
+		meta_copy = g_malloc0(sizeof(struct sr_datafeed_meta));
+		g_slist_foreach(meta->config, (GFunc)copy_src, meta_copy->config);
+		(*copy)->payload = meta_copy;
+		break;
+	case SR_DF_LOGIC:
+		logic = packet->payload;
+		logic_copy = g_malloc(sizeof(logic));
+		logic_copy->length = logic->length;
+		logic_copy->unitsize = logic->unitsize;
+		memcpy(logic_copy->data, logic->data, logic->length * logic->unitsize);
+		(*copy)->payload = logic_copy;
+		break;
+	case SR_DF_ANALOG:
+		analog = packet->payload;
+		analog_copy = g_malloc(sizeof(analog));
+		analog_copy->channels = g_slist_copy(analog->channels);
+		analog_copy->num_samples = analog->num_samples;
+		analog_copy->mq = analog->mq;
+		analog_copy->unit = analog->unit;
+		analog_copy->mqflags = analog->mqflags;
+		memcpy(analog_copy->data, analog->data,
+				analog->num_samples * sizeof(float));
+		(*copy)->payload = analog_copy;
+		break;
+	default:
+		sr_err("Unknown packet type %d", packet->type);
+		return SR_ERR;
+	}
+
+	return SR_OK;
+}
+
+void sr_packet_free(struct sr_datafeed_packet *packet)
+{
+	const struct sr_datafeed_meta *meta;
+	const struct sr_datafeed_logic *logic;
+	const struct sr_datafeed_analog *analog;
+	struct sr_config *src;
+	GSList *l;
+
+	switch (packet->type) {
+	case SR_DF_TRIGGER:
+	case SR_DF_END:
+		/* No payload. */
+		break;
+	case SR_DF_HEADER:
+		/* Payload is a simple struct. */
+		g_free((void *)packet->payload);
+		break;
+	case SR_DF_META:
+		meta = packet->payload;
+		for (l = meta->config; l; l = l->next) {
+			src = l->data;
+			g_variant_unref(src->data);
+			g_free(src);
+		}
+		g_slist_free(meta->config);
+		g_free((void *)packet->payload);
+		break;
+	case SR_DF_LOGIC:
+		logic = packet->payload;
+		g_free(logic->data);
+		g_free((void *)packet->payload);
+		break;
+	case SR_DF_ANALOG:
+		analog = packet->payload;
+		g_slist_free(analog->channels);
+		g_free(analog->data);
+		g_free((void *)packet->payload);
+		break;
+	default:
+		sr_err("Unknown packet type %d", packet->type);
+	}
+	g_free(packet);
+
 }
 
 /** @} */