[collectd] [PATCH 4/5] sigrok: Use separate thread for all I/O

[Bert Vermeulen]

---
 src/sigrok.c | 110 +++++++++++++++++++++++++++++++++++------------------------
 1 file changed, 66 insertions(+), 44 deletions(-)

diff --git a/src/sigrok.c b/src/sigrok.c
index ea1e95e..89ef61c 100644
--- a/src/sigrok.c
+++ b/src/sigrok.c
@@ -19,15 +19,22 @@
 #include "collectd.h"
 #include "common.h"
 #include "plugin.h"
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <time.h>
+#include <pthread.h>
+
 #include <glib.h>
 #include <libsigrok/libsigrok.h>
 
+/* Minimum interval between dispatches coming from this plugin. The RRD
+ * plugin, at least, complains when written to with sub-second intervals.*/
 #define DEFAULT_MIN_WRITE_INTERVAL 1
 
+static pthread_t sr_thread;
+static int sr_thread_running = FALSE;
 GSList *config_devices;
 static struct sr_session *session = NULL;
 static int num_devices;
@@ -222,34 +229,27 @@ static void plugin_feed_callback(const struct sr_dev_inst *sdi,
 
 }
 
-static int plugin_read(user_data_t *ud)
-{
-
-	sr_session_iteration(FALSE);
-
-	return 0;
-}
-
-static int plugin_init(void)
+static void *thread_init(void *arg)
 {
 	struct sr_dev_driver *drv, **drvlist;
 	struct sr_config *src;
 	GSList *devlist, *drvopts, *l;
 	struct config_device *cfdev;
-	struct timespec ts;
 	int ret, i;
 	char hwident[512];
 
+	(void)arg;
+
 	sr_log_callback_set(cd_logger, NULL);
 	sr_log_loglevel_set(loglevel);
 
 	if ((ret = sr_init(&sr_ctx)) != SR_OK) {
 		ERROR("Failed to initialize libsigrok: %s.", sr_strerror(ret));
-		return 1;
+		return NULL;
 	}
 
 	if (!(session = sr_session_new()))
-		return 1;
+		return NULL;
 
 	num_devices = 0;
 	drvlist = sr_driver_list();
@@ -264,37 +264,37 @@ static int plugin_init(void)
 		}
 		if (!drv) {
 			ERROR("sigrok: Unknown driver '%s'.", cfdev->driver);
-			return 1;
+			return NULL;
 		}
 
 		if (sr_driver_init(sr_ctx, drv) != SR_OK)
-			return 1;
+			return NULL;
 
 		drvopts = NULL;
 		if (cfdev->conn) {
 			if (!(src = malloc(sizeof(struct sr_config))))
-				return 1;
+				return NULL;
 			src->key = SR_CONF_CONN;
 			src->data = g_variant_new_string(cfdev->conn);
 			drvopts = g_slist_append(drvopts, src);
 		}
 		if (cfdev->serialcomm) {
 			if (!(src = malloc(sizeof(struct sr_config))))
-				return 1;
+				return NULL;
 			src->key = SR_CONF_SERIALCOMM;
 			src->data = g_variant_new_string(cfdev->serialcomm);
 			drvopts = g_slist_append(drvopts, src);
 		}
 		devlist = sr_driver_scan(drv, drvopts);
 		g_slist_free_full(drvopts, (GDestroyNotify)free_drvopts);
-		if (!devlist) {
-			INFO("sigrok: No devices found.");
-			return 0;
-		}
+		if (!devlist)
+			/* No devices found for this driver. */
+			continue;
+
 		if (g_slist_length(devlist) > 1) {
 			INFO("sigrok: %d sigrok devices for device entry '%s': must be 1.",
 					g_slist_length(devlist), cfdev->name);
-			return 1;
+			return NULL;
 		}
 		cfdev->sdi = devlist->data;
 		g_slist_free(devlist);
@@ -305,28 +305,54 @@ static int plugin_init(void)
 		INFO("sigrok: Device '%s' is a %s.", cfdev->name, hwident);
 
 		if (sr_dev_open(cfdev->sdi) != SR_OK)
-			return 1;
+			return NULL;
 
 		if (sr_session_dev_add(cfdev->sdi) != SR_OK)
-			return 1;
+			return NULL;
 
 		num_devices++;
 	}
 
 	if (num_devices > 0) {
 		/* Do this only when we're sure there's hardware to talk to. */
-		ts.tv_sec = 0;
-		ts.tv_nsec = 1000000L;
-		plugin_register_complex_read("sigrok", "sigrok", plugin_read,
-				&ts, NULL);
-
 		if (sr_session_datafeed_callback_add(plugin_feed_callback, NULL) != SR_OK)
-			return 1;
+			return NULL;
 
+		/* Start acquisition on all devices. */
 		if (sr_session_start() != SR_OK)
-			return 1;
-	} else
-		sr_session_destroy();
+			return NULL;
+
+		/* Main loop, runs forever. */
+		sr_session_run();
+
+		sr_session_stop();
+		sr_session_dev_remove_all();
+	}
+
+	sr_session_destroy();
+
+	sr_exit(sr_ctx);
+
+	pthread_exit(NULL);
+	sr_thread_running = FALSE;
+
+	return NULL;
+}
+
+static int plugin_init(void)
+{
+	int status;
+
+	if (sr_thread_running) {
+		ERROR("sigrok: Thread already running.");
+		return -1;
+	}
+
+	if ((status = plugin_thread_create(&sr_thread, NULL, thread_init, NULL)) != 0) {
+		ERROR("sigrok: Failed to create thread: %s.", strerror(status));
+		return -1;
+	}
+	sr_thread_running = TRUE;
 
 	return 0;
 }
@@ -336,24 +362,20 @@ static int plugin_shutdown(void)
 	struct config_device *cfdev;
 	GSList *l;
 
-	if (num_devices > 0) {
-		sr_session_stop();
-		sr_session_dev_remove_all();
-		sr_session_destroy();
+	if (sr_thread_running) {
+		pthread_cancel(sr_thread);
+		pthread_join(sr_thread, NULL);
 	}
 
 	for (l = config_devices; l; l = l->next) {
 		cfdev = l->data;
 		free(cfdev->name);
-		if (cfdev->driver)
-			free(cfdev->driver);
-		if (cfdev->conn)
-			free(cfdev->conn);
-		if (cfdev->serialcomm)
-			free(cfdev->serialcomm);
+		free(cfdev->driver);
+		free(cfdev->conn);
+		free(cfdev->serialcomm);
+		free(cfdev);
 	}
-
-	sr_exit(sr_ctx);
+	g_slist_free(config_devices);
 
 	return 0;
 }
-- 
1.8.1.2