show: Format channel output when no channel is available

[sigrok-cli.git] / device.c

diff --git a/device.c b/device.c
index 17505e26a59e60a44b7b7e50f3db8f3630499759..7da744431154c134b5bee897bc24f817cc774e46 100644 (file)
--- a/device.c
+++ b/device.c
@@ -17,12 +17,10 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <config.h>
 #include <glib.h>
 #include <string.h>
 #include "sigrok-cli.h"
-#include "config.h"
-
-extern struct sr_context *sr_ctx;
 
 static void free_drvopts(struct sr_config *src)
 {
@@ -37,14 +35,18 @@ GSList *device_scan(void)
        int i;
 
        if (opt_drv) {
+               /* Caller specified driver. Use it. Only this one. */
                if (!parse_driver(opt_drv, &driver, &drvopts))
                        return NULL;
                devices = sr_driver_scan(driver, drvopts);
                g_slist_free_full(drvopts, (GDestroyNotify)free_drvopts);
+       } else if (opt_dont_scan) {
+               /* No -d choice, and -D "don't scan" requested. Do nothing. */
+               devices = NULL;
        } else {
-               /* No driver specified, let them all scan on their own. */
+               /* No driver specified. Scan all available drivers. */
                devices = NULL;
-               drivers = sr_driver_list();
+               drivers = sr_driver_list(sr_ctx);
                for (i = 0; drivers[i]; i++) {
                        driver = drivers[i];
                        if (sr_driver_init(sr_ctx, driver) != SR_OK) {
@@ -61,16 +63,37 @@ GSList *device_scan(void)
        return devices;
 }
 
-struct sr_channel_group *select_channel_group(struct sr_dev_inst *sdi)
+/**
+ * Lookup a channel group from its name.
+ *
+ * Uses the caller specified channel group name, or a previously stored
+ * option value as a fallback. Returns a reference to the channel group
+ * when the lookup succeeded, or #NULL after lookup failure, as well as
+ * #NULL for the global channel group (the device).
+ *
+ * Accepts either #NULL pointer, or an empty string, or the "global"
+ * literal to address the global channel group (the device). Emits an
+ * error message when the lookup failed while a name was specified.
+ *
+ * @param[in] sdi Device instance.
+ * @param[in] cg_name Caller provided channel group name.
+ *
+ * @returns The channel group, or #NULL for failed lookup.
+ */
+struct sr_channel_group *lookup_channel_group(struct sr_dev_inst *sdi,
+       const char *cg_name)
 {
        struct sr_channel_group *cg;
        GSList *l, *channel_groups;
 
-       if (!opt_channel_group)
+       if (!cg_name)
+               cg_name = opt_channel_group;
+       if (cg_name && g_ascii_strcasecmp(cg_name, "global") == 0)
+               cg_name = NULL;
+       if (!cg_name || !*cg_name)
                return NULL;
 
        channel_groups = sr_dev_inst_channel_groups_get(sdi);
-
        if (!channel_groups) {
                g_critical("This device does not have any channel groups.");
                return NULL;
@@ -78,11 +101,11 @@ struct sr_channel_group *select_channel_group(struct sr_dev_inst *sdi)
 
        for (l = channel_groups; l; l = l->next) {
                cg = l->data;
-               if (!strcasecmp(opt_channel_group, cg->name)) {
-                       return cg;
-               }
+               if (g_ascii_strcasecmp(cg_name, cg->name) != 0)
+                       continue;
+               return cg;
        }
-       g_critical("Invalid channel group '%s'", opt_channel_group);
+       g_critical("Invalid channel group '%s'", cg_name);
 
        return NULL;
 }