ucm: add possibility to keep order of childs for If blocks

Because of the nature of the structured parser, it is not guaranteed
that the order of the parsed tree is equal to the lines in the source.

Add possibility to insert the If results before or after the selected
identifier like:

SectionDevice."Speaker" {
  ...
}

If.1 {
	Condition { ... }
	Before.SectionDevice "Speaker"
	True { ... }
}
If.2 {
	Condition { ... }
	After.SectionDevice "Speaker"
	True { ... }
}

If the "After" or "Before" identifiers are not found, the result is added
after the last entry in the block.

Signed-off-by: Jaroslav Kysela <perex@perex.cz>

src/ucm/parser.c

@@ -175,7 +175,9 @@ static int evaluate_condition(snd_use_case_mgr_t *uc_mgr,
 	if (err < 0)
 		return err;
 
-	return uc_mgr_evaluate_condition(uc_mgr, cfg, n);
+	err = uc_mgr_evaluate_condition(uc_mgr, cfg, n);
+	snd_config_delete(n);
+	return err;
 }
 
 /*

src/ucm/ucm_cond.c

@@ -250,7 +250,9 @@ static int if_eval(snd_use_case_mgr_t *uc_mgr, snd_config_t *eval)
 
 static int if_eval_one(snd_use_case_mgr_t *uc_mgr,
 		       snd_config_t *cond,
-		       snd_config_t **result)
+		       snd_config_t **result,
+		       snd_config_t **before,
+		       snd_config_t **after)
 {
 	snd_config_t *expr, *_true = NULL, *_false = NULL;
 	int err;
@@ -279,6 +281,18 @@ static int if_eval_one(snd_use_case_mgr_t *uc_mgr,
 		return -EINVAL;
 	}
 
+	err = snd_config_search(cond, "Before", before);
+	if (err < 0 && err != -ENOENT) {
+		uc_error("before block identifier error");
+		return -EINVAL;
+	}
+
+	err = snd_config_search(cond, "After", after);
+	if (err < 0 && err != -ENOENT) {
+		uc_error("before block identifier error");
+		return -EINVAL;
+	}
+
 	err = if_eval(uc_mgr, expr);
 	if (err > 0) {
 		*result = _true;
@@ -302,10 +316,13 @@ static void config_dump(snd_config_t *cfg)
 }
 #endif
 
-static int compound_merge(snd_config_t *dst, snd_config_t *src)
+static int compound_merge(const char *id,
+			  snd_config_t *dst, snd_config_t *src,
+			  snd_config_t *before, snd_config_t *after)
 {
 	snd_config_iterator_t i, next;
-	snd_config_t *n;
+	snd_config_t *n, *_before = NULL, *_after = NULL;
+	const char *s;
 	int err;
 
 	if (snd_config_get_type(src) != SND_CONFIG_TYPE_COMPOUND) {
@@ -313,14 +330,52 @@ static int compound_merge(snd_config_t *dst, snd_config_t *src)
 		return -EINVAL;
 	}
 
+	if (before) {
+		err = get_string(before, id, &s);
+		if (err < 0 && err != -ENOENT)
+			return err;
+		if (err == 0) {
+			err = snd_config_search(dst, s, &_before);
+			if (err < 0 && err != -ENOENT)
+				return err;
+		}
+	}
+	if (after) {
+		err = get_string(after, id, &s);
+		if (err < 0 && err != -ENOENT)
+			return err;
+		if (err == 0) {
+			err = snd_config_search(dst, s, &_after);
+			if (err < 0 && err != -ENOENT)
+				return err;
+		}
+	}
+
+	if (_before && _after) {
+		uc_error("defined both before and after identifiers in the If block");
+		return -EINVAL;
+	}
+
 	snd_config_for_each(i, next, src) {
 		n = snd_config_iterator_entry(i);
 		err = snd_config_remove(n);
 		if (err < 0)
 			return err;
-		err = snd_config_add(dst, n);
+		if (_before) {
-		if (err < 0) {
+			err = snd_config_add_before(_before, n);
-			return err;
+			if (err < 0)
+				return err;
+			_before = NULL;
+			_after = n;
+		} else if (_after) {
+			err = snd_config_add_after(_after, n);
+			if (err < 0)
+				return err;
+			_after = n;
+		} else {
+			err = snd_config_add(dst, n);
+			if (err < 0)
+				return err;
 		}
 	}
 
@@ -335,7 +390,7 @@ int uc_mgr_evaluate_condition(snd_use_case_mgr_t *uc_mgr,
 			      snd_config_t *cond)
 {
 	snd_config_iterator_t i, i2, next, next2;
-	snd_config_t *a, *n, *n2, *parent2;
+	snd_config_t *a, *n, *n2, *parent2, *before, *after;
 	const char *id;
 	int err;
 
@@ -351,9 +406,12 @@ int uc_mgr_evaluate_condition(snd_use_case_mgr_t *uc_mgr,
 
 	snd_config_for_each(i, next, cond) {
 		n = snd_config_iterator_entry(i);
-		err = if_eval_one(uc_mgr, n, &a);
+		before = after = NULL;
+		err = if_eval_one(uc_mgr, n, &a, &before, &after);
 		if (err < 0)
 			return err;
+		if (a == NULL)
+			continue;
 		err = snd_config_search(a, "If", &n2);
 		if (err < 0 && err != -ENOENT) {
 			uc_error("If block error (If)");
@@ -380,7 +438,7 @@ __add:
 				err = snd_config_search(parent, id, &parent2);
 				if (err == -ENOENT)
 					goto __add;
-				err = compound_merge(parent2, n2);
+				err = compound_merge(id, parent2, n2, before, after);
 				if (err < 0)
 					return err;
 			}