ucm: simplify and fix the previous patch (geti)

Use macro to maintain only one code. The status may be 0 or 1 - handle
both values correctly.

Also, fix the possible memory leak in snd_use_case_geti() - string
str should be freed even when the error is returned.

Fixes: 436cd5b ("ucm: add existence checks to geti calls")
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

src/ucm/main.c

@@ -2415,67 +2415,23 @@ int snd_use_case_get(snd_use_case_mgr_t *uc_mgr,
 	return err;
 }
 
-/**
- * \brief check device status and existance
- * \param uc_mgr Use case manager
- * \param str device identifier
- * \param value Value pointer
- * \return Zero if success, otherwise a negative error code
- */
-static long check_device(snd_use_case_mgr_t *uc_mgr,
-		      const char *str,
-		      long *value)
-{
-	struct use_case_device *dev;
-	int err;
-
-	if (!str) {
-		return -EINVAL;
-	}
-	err = device_status(uc_mgr, str);
-	if (err > 0) {
-		*value = err;
-		err = 0;
-	} else if (err < 0) {
-		return err;
-	}
-	dev = find_device(uc_mgr, uc_mgr->active_verb, str, 0);
-	if (!dev) {
-		return -ENOENT;
-	}
-	return 0;
-}
-
-/**
- * \brief check modifier status and existance
- * \param uc_mgr Use case manager
- * \param str modifier identifier
- * \param value Value pointer
- * \return Zero if success, otherwise a negative error code
+/*
+ * a helper macro to obtain status and existence
  */
-static long check_modifier(snd_use_case_mgr_t *uc_mgr,
-		      const char *str,
-		      long *value)
-{
-	struct use_case_modifier *mod;
-	long err;
-
-	if (!str) {
-		return -EINVAL;
-	}
-	err = modifier_status(uc_mgr, str);
-	if (err > 0) {
-		*value = err;
-		return 0;
-	} else if (err < 0) {
-		return err;
-	}
-	mod = find_modifier(uc_mgr, uc_mgr->active_verb, str, 0);
-	if (!mod) {
-		return -ENOENT;
-	}
-	return 0;
-}
+#define geti(uc_mgr, status, ifind, str, value) ({ \
+	long val = -EINVAL; \
+	if (str) { \
+		val = (status)((uc_mgr), (str)); \
+		if (val >= 0) { \
+			if ((ifind)((uc_mgr), (uc_mgr)->active_verb, (str), 0)) { \
+				*(value) = val; \
+			} else { \
+				val = -ENOENT; \
+			} \
+		} \
+	} \
+	; val; /* return value */ \
+})
 
 /**
  * \brief Get current - integer
@@ -2488,7 +2444,7 @@ int snd_use_case_geti(snd_use_case_mgr_t *uc_mgr,
 		      long *value)
 {
 	char *str, *str1;
-	long err;
+	int err;
 
 	pthread_mutex_lock(&uc_mgr->mutex);
 	if (0) {
@@ -2505,21 +2461,15 @@ int snd_use_case_geti(snd_use_case_mgr_t *uc_mgr,
 			str = NULL;
 		}
 		if (check_identifier(identifier, "_devstatus")) {
-			err = check_device(uc_mgr, str, value);
-			if (err < 0) {
-				goto __end;
-			}
+			err = geti(uc_mgr, device_status, find_device, str, value);
 		} else if (check_identifier(identifier, "_modstatus")) {
-			err = check_modifier(uc_mgr, str, value);
-			if (err < 0) {
-				goto __end;
-			}
+			err = geti(uc_mgr, modifier_status, find_modifier, str, value);
 #if 0
 		/*
 		 * enable this block if the else clause below is expanded to query
 		 * user-supplied values
 		 */
-		} else if (identifier[0] == '_')
+		} else if (identifier[0] == '_') {
 			err = -ENOENT;
 #endif
 		} else