scan: Rework scanning

Instead of going through the list of enabled backends and checking for
each one whether or not we were asked to scan from it, we now go through
the user-supplied backends list, find the corresponding backend, and
call its scan function.

This change will make it possible to support scanning from the same
backend multiple times, for instance with different USB devices.

Signed-off-by: Paul Cercueil <[email protected]>

scan.c

@@ -14,9 +14,7 @@
 #include <string.h>
 
 struct iio_scan_context {
-	bool scan_usb;
-	bool scan_network;
-	bool scan_local;
+	char *backendopts;
 };
 
 const char * iio_context_info_get_description(
@@ -35,37 +33,34 @@ ssize_t iio_scan_context_get_info_list(struct iio_scan_context *ctx,
 		struct iio_context_info ***info)
 {
 	struct iio_scan_result scan_result = { 0, NULL };
-
-	if (WITH_LOCAL_BACKEND && ctx->scan_local) {
-		int ret = local_context_scan(&scan_result);
-		if (ret < 0) {
-			if (scan_result.info)
-				iio_context_info_list_free(scan_result.info);
-			return ret;
-		}
-	}
-
-	if (WITH_USB_BACKEND && ctx->scan_usb) {
-		int ret = usb_context_scan(&scan_result);
-		if (ret < 0) {
-			if (scan_result.info)
-				iio_context_info_list_free(scan_result.info);
-			return ret;
-		}
-	}
-
-	if (HAVE_DNS_SD && ctx->scan_network) {
-		int ret = dnssd_context_scan(&scan_result);
-		if (ret < 0) {
-			if (scan_result.info)
-				iio_context_info_list_free(scan_result.info);
-			return ret;
+	char *token, *rest=NULL;
+	ssize_t ret;
+
+	for (token = iio_strtok_r(ctx->backendopts, ":", &rest);
+			token; token = iio_strtok_r(NULL, ":", &rest)) {
+
+		/* Since tokens are all null terminated, it's safe to use strcmp on them */
+		if (WITH_LOCAL_BACKEND && !strcmp(token, "local")) {
+			ret = local_context_scan(&scan_result);
+		} else if (WITH_USB_BACKEND && !strcmp(token, "usb")) {
+			ret = usb_context_scan(&scan_result);
+		} else if (HAVE_DNS_SD && !strcmp(token, "ip")) {
+			ret = dnssd_context_scan(&scan_result);
+		} else {
+			ret = -ENODEV;
 		}
+		if (ret < 0)
+			goto err_free_scan_result_info;
 	}
 
 	*info = scan_result.info;
 
 	return (ssize_t) scan_result.size;
+
+err_free_scan_result_info:
+	if (scan_result.info)
+		iio_context_info_list_free(scan_result.info);
+	return ret;
 }
 
 void iio_context_info_list_free(struct iio_context_info **list)
@@ -126,20 +121,19 @@ struct iio_scan_context * iio_create_scan_context(
 		return NULL;
 	}
 
-	if (!backend || strstr(backend, "local"))
-		ctx->scan_local = true;
-
-	if (!backend || strstr(backend, "usb"))
-		ctx->scan_usb = true;
-
-	if (!backend || strstr(backend, "ip"))
-		ctx->scan_network = true;
+	ctx->backendopts = iio_strndup(backend ? backend : "local:usb:ip", PATH_MAX);
+	if (!ctx->backendopts) {
+		free(ctx);
+		errno = ENOMEM;
+		return NULL;
+	}
 
 	return ctx;
 }
 
 void iio_scan_context_destroy(struct iio_scan_context *ctx)
 {
+	free(ctx->backendopts);
 	free(ctx);
 }