alsaucm: add json dump command

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

alsaucm/dump.c

@@ -32,10 +32,14 @@ struct renderer {
 			  const char *verb,
 			  const char *comment);
 	int (*verb_end)(struct renderer *r);
+	int (*device_block_begin)(struct renderer *r);
+	int (*device_block_end)(struct renderer *r);
 	int (*device_begin)(struct renderer *r,
 			    const char *device,
 			    const char *comment);
 	int (*device_end)(struct renderer *r);
+	int (*modifier_block_begin)(struct renderer *r);
+	int (*modifier_block_end)(struct renderer *r);
 	int (*modifier_begin)(struct renderer *r,
 			      const char *device,
 			      const char *comment);
@@ -52,6 +56,10 @@ struct renderer {
 	void *opaque;
 };
 
+/*
+ * Text renderer
+ */
+
 struct text {
 	char a[1];
 };
@@ -177,12 +185,12 @@ static int text_con_start(struct renderer *r)
 
 static int text_value_begin(struct renderer *r)
 {
-	return text_2nd_level(r, "Values [\n");
+	return text_2nd_level(r, "Values {\n");
 }
 
 static int text_value_end(struct renderer *r)
 {
-	return text_2nd_level(r, "]\n");
+	return text_2nd_level(r, "}\n");
 }
 
 static int text_value(struct renderer *r, const char *ident, const char *value)
@@ -217,6 +225,220 @@ static struct renderer text_renderer = {
 	.value = text_value,
 };
 
+/*
+ * JSON renderer
+ */
+
+struct json {
+	int block[5];
+};
+
+static char *jesc(const char *s, char *buf, size_t buf_len)
+{
+	char *dst = buf;
+	char c = '"';
+	*dst++ = c;
+	buf_len--;
+	while (*s && buf_len > 2) {
+		if (*s == '\"') {
+			if (buf_len > 3) {
+				*dst++ = '"';
+				*dst++ = *s++;
+				buf_len -= 2;
+				continue;
+			} else {
+				break;
+			}
+		}
+		*dst++ = *s++;
+	}
+	*dst++ = c;
+	*dst = '\0';
+	return buf;
+}
+
+#define JESC(s, esc) jesc((s), (esc), sizeof(esc))
+
+static void json_block(struct renderer *r, int level, int last)
+{
+	struct json *j = r->opaque;
+	printf((j->block[level] && !last) ? ",\n" : "\n");
+	j->block[level] = last ? 0 : 1;
+}
+
+static int json_init(struct renderer *r)
+{
+	printf("{\n  \"Verbs\": {");
+	return 0;
+}
+
+static void json_done(struct renderer *r)
+{
+	json_block(r, 0, 1);
+	printf("  }\n}\n");
+}
+
+static int json_verb_start(struct renderer *r, const char *verb, const char *comment)
+{
+	char buf[256];
+	json_block(r, 0, 0);
+	printf("    %s: {", JESC(verb, buf));
+	if (comment && comment[0]) {
+		json_block(r, 1, 0);
+		printf("      \"Comment\": %s", JESC(comment, buf));
+	}
+	return 0;
+}
+
+static int json_verb_end(struct renderer *r)
+{
+	json_block(r, 1, 1);
+	printf("    }");
+	return 0;
+}
+
+static int json_2nd_level_block_end(struct renderer *r)
+{
+	json_block(r, 2, 1);
+	printf("      }");
+	return 0;
+}
+
+static int json_2nd_level_begin(struct renderer *r,
+				const char *val,
+				const char *comment)
+{
+	char buf[256];
+	json_block(r, 2, 0);
+	printf("        %s: {", JESC(val, buf));
+	if (comment && comment[0]) {
+		json_block(r, 3, 0);
+		printf("          \"Comment\": %s", JESC(comment, buf));
+	}
+	return 0;
+}
+
+static int json_2nd_level_end(struct renderer *r)
+{
+	json_block(r, 3, 1);
+	printf("        }");
+	return 0;
+}
+
+static int json_2nd_level(struct renderer *r, const char *txt)
+{
+	printf("          %s", txt);
+	return 0;
+}
+
+static int json_3rd_level(struct renderer *r, const char *txt)
+{
+	printf("            %s", txt);
+	return 0;
+}
+
+static int json_dev_block_start(struct renderer *r)
+{
+	json_block(r, 1, 0);
+	printf("      \"Devices\": {");
+	return 0;
+}
+
+static int json_mod_block_start(struct renderer *r)
+{
+	json_block(r, 1, 0);
+	printf("      \"Modifiers\": {");
+	return 0;
+}
+
+static int json_supcon_start(struct renderer *r, const char *key)
+{
+	json_block(r, 3, 0);
+	if (json_2nd_level(r, key))
+		return 1;
+	printf(": [");
+	return 0;
+}
+
+static int json_supcon_value(struct renderer *r, const char *value, int last)
+{
+	char buf[256];
+	JESC(value, buf);
+	json_block(r, 4, 0);
+	return json_3rd_level(r, buf);
+}
+
+static int json_supcon_end(struct renderer *r)
+{
+	json_block(r, 4, 1);
+	return json_2nd_level(r, "]");
+}
+
+static int json_sup_start(struct renderer *r)
+{
+	return json_supcon_start(r, "\"SupportedDevices\"");
+}
+
+static int json_con_start(struct renderer *r)
+{
+	return json_supcon_start(r, "\"ConflictingDevices\"");
+}
+
+static int json_value_begin(struct renderer *r)
+{
+	json_block(r, 3, 0);
+	return json_2nd_level(r, "\"Values\": {");
+}
+
+static int json_value_end(struct renderer *r)
+{
+	json_block(r, 4, 1);
+	return json_2nd_level(r, "}");
+}
+
+static int json_value(struct renderer *r, const char *ident, const char *value)
+{
+	char buf[256];
+	int err;
+
+	json_block(r, 4, 0);
+	JESC(ident, buf);
+	err = json_3rd_level(r, buf);
+	if (err < 0)
+		return err;
+	JESC(value, buf);
+	printf(": %s", buf);
+	return 0;
+}
+
+static struct renderer json_renderer = {
+	.init = json_init,
+	.done = json_done,
+	.verb_begin = json_verb_start,
+	.verb_end = json_verb_end,
+	.device_block_begin = json_dev_block_start,
+	.device_block_end = json_2nd_level_block_end,
+	.device_begin = json_2nd_level_begin,
+	.device_end = json_2nd_level_end,
+	.modifier_block_begin = json_mod_block_start,
+	.modifier_block_end = json_2nd_level_block_end,
+	.modifier_begin = json_2nd_level_begin,
+	.modifier_end = json_2nd_level_end,
+	.supported_begin = json_sup_start,
+	.supported_value = json_supcon_value,
+	.supported_end = json_supcon_end,
+	.conflict_begin = json_con_start,
+	.conflict_value = json_supcon_value,
+	.conflict_end = json_supcon_end,
+	.value_begin = json_value_begin,
+	.value_end = json_value_end,
+	.value = json_value,
+};
+
+/*
+ * universal dump functions
+ */
+
 static int render_devlist(struct context *context,
 			  struct renderer *render,
 			  const char *verb,
@@ -350,6 +572,12 @@ static void render(struct context *context, struct renderer *render)
 							context->command, verb);
 			continue;
 		}
+		if (dev_num == 0)
+			goto __mods;
+		if (render->device_block_begin && render->device_block_begin(render)) {
+			snd_use_case_free_list(dev_list, dev_num);
+			goto __end;
+		}
 		for (j = 0; j < dev_num; j += 2) {
 			render->device_begin(render, dev_list[j + 0], dev_list[j + 1]);
 			if (render_device(context, render, verb, dev_list[j + 0])) {
@@ -359,6 +587,9 @@ static void render(struct context *context, struct renderer *render)
 			render->device_end(render);
 		}
 		snd_use_case_free_list(dev_list, dev_num);
+		if (render->device_block_end && render->device_block_end(render))
+			goto __end;
+__mods:
 		/* modifiers */
 		snprintf(buf, sizeof(buf), "_modifiers/%s", verb);
 		dev_num = snd_use_case_get_list(uc_mgr, buf, &dev_list);
@@ -367,11 +598,20 @@ static void render(struct context *context, struct renderer *render)
 							context->command, verb);
 			continue;
 		}
+		if (dev_num == 0)
+			goto __verb_end;
+		if (render->modifier_block_begin && render->modifier_block_begin(render)) {
+			snd_use_case_free_list(dev_list, dev_num);
+			goto __end;
+		}
 		for (j = 0; j < dev_num; j += 2) {
 			render->modifier_begin(render, dev_list[j + 0], dev_list[j + 1]);
 			render->modifier_end(render);
 		}
 		snd_use_case_free_list(dev_list, dev_num);
+		if (render->modifier_block_end && render->modifier_block_end(render))
+			goto __end;
+__verb_end:
 		/* end */
 		if (render->verb_end(render))
 			break;
@@ -385,14 +625,19 @@ __end:
 void dump(struct context *context, const char *format)
 {
 	struct renderer r;
+	struct text t;
+	struct json j;
 
 	r.opaque = NULL;
 	if (strcasecmp(format, "text") == 0 ||
 	    strcasecmp(format, "txt") == 0) {
-		struct text t;
 		memset(&t, 0, sizeof(t));
 		r = text_renderer;
 		r.opaque = &t;
+	} else if (strcasecmp(format, "json") == 0) {
+		memset(&j, 0, sizeof(j));
+		r = json_renderer;
+		r.opaque = &j;
 	}
 	if (r.opaque != NULL) {
 		render(context, &r);

alsaucm/usecase.c

@@ -108,7 +108,7 @@ static void dump_help(struct context *context)
 "  reset                      reset sound card to default state\n"
 "  reload                     reload configuration\n"
 "  listcards                  list available cards\n"
-"  dump FORMAT                dump all config information (format: text)\n"
+"  dump FORMAT                dump all config information (format: text,json)\n"
 "  list IDENTIFIER            list command, for items with value + comment\n"
 "  list1 IDENTIFIER           list command, for items without comments\n"
 "  get IDENTIFIER             get string value\n"