spa: spa-json-dump: read also from stdin, and report syntax errors

Support reading from stdin and report syntax errors.

Also don't do extra spa_json_enter when inserting a dummy "{" when
parsing files with top-level keys.  In this case the tokenizer is
already "entered" after spa_json_init, and will give parse error when we
are not inserting the closing "}" for the dummy "{".

doc/dox/programs/spa-json-dump.1.md

@@ -4,11 +4,11 @@ SPA JSON to JSON converter
 
 # SYNOPSIS
 
-**spa-json** *FILE*
+**spa-json** *[FILE]*
 
 # DESCRIPTION
 
-Reads a SPA JSON file, and outputs it as standard JSON.
+Reads a SPA JSON file or stdin, and outputs it as standard JSON.
 
 # EXAMPLES
 

spa/tools/spa-json-dump.c

@@ -54,22 +54,33 @@ static void encode_string(FILE *f, const char *val, int len)
 static int dump(FILE *file, int indent, struct spa_json *it, const char *value, int len)
 {
 	struct spa_json sub;
-	int count = 0;
+	bool toplevel = false;
+	int count = 0, res;
 	char key[1024];
 
+	if (!value) {
+		toplevel = true;
+		value = "{";
+		len = 1;
+	}
+
 	if (spa_json_is_array(value, len)) {
 		fprintf(file, "[");
 		spa_json_enter(it, &sub);
 		while ((len = spa_json_next(&sub, &value)) > 0) {
 			fprintf(file, "%s\n%*s", count++ > 0 ? "," : "",
 					indent+2, "");
-			dump(file, indent+2, &sub, value, len);
+			if ((res = dump(file, indent+2, &sub, value, len)) < 0)
+				return res;
 		}
 		fprintf(file, "%s%*s]", count > 0 ? "\n" : "",
 				count > 0 ? indent : 0, "");
 	} else if (spa_json_is_object(value, len)) {
 		fprintf(file, "{");
-		spa_json_enter(it, &sub);
+		if (!toplevel)
+			spa_json_enter(it, &sub);
+		else
+			sub = *it;
 		while (spa_json_get_string(&sub, key, sizeof(key)) > 0) {
 			fprintf(file, "%s\n%*s",
 					count++ > 0 ? "," : "",
@@ -78,8 +89,15 @@ static int dump(FILE *file, int indent, struct spa_json *it, const char *value,
 			fprintf(file, ": ");
 			if ((len = spa_json_next(&sub, &value)) <= 0)
 				break;
-			dump(file, indent+2, &sub, value, len);
+			res = dump(file, indent+2, &sub, value, len);
+			if (res < 0) {
+				if (toplevel)
+					*it = sub;
+				return res;
+			}
 		}
+		if (toplevel)
+			*it = sub;
 		fprintf(file, "%s%*s}", count > 0 ? "\n" : "",
 				count > 0 ? indent : 0, "");
 	} else if (spa_json_is_string(value, len) ||
@@ -91,21 +109,96 @@ static int dump(FILE *file, int indent, struct spa_json *it, const char *value,
 	} else {
 		encode_string(file, value, len);
 	}
+
+	if (spa_json_get_error(it, NULL, NULL, NULL))
+		return -EINVAL;
+
 	return 0;
 }
 
+static int process_json(const char *filename, void *buf, size_t size)
+{
+	int len, res;
+	struct spa_json it;
+	const char *value;
+
+	spa_json_init(&it, buf, size);
+	if ((len = spa_json_next(&it, &value)) <= 0) {
+                fprintf(stderr, "not a valid file '%s': %s\n", filename, spa_strerror(len));
+		return -EINVAL;
+	}
+	if (!spa_json_is_container(value, len)) {
+		spa_json_init(&it, buf, size);
+		value = NULL;
+		len = 0;
+	}
+	res = dump(stdout, 0, &it, value, len);
+	if (spa_json_next(&it, &value) < 0)
+		res = -EINVAL;
+
+	fprintf(stdout, "\n");
+	fflush(stdout);
+
+	if (res < 0) {
+		int line, col;
+
+		if (spa_json_get_error(&it, buf, &line, &col))
+			fprintf(stderr, "syntax error in file '%s': at line:%d col:%d\n", filename, line, col);
+		else
+			fprintf(stderr, "error parsing file '%s': %s\n", filename, spa_strerror(res));
+
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int process_stdin(void)
+{
+	uint8_t *buf = NULL, *p;
+	size_t alloc = 0, size = 0, read_size, res;
+	int err;
+
+	do {
+		alloc += 1024 + alloc;
+		p = realloc(buf, alloc);
+		if (!p) {
+			fprintf(stderr, "error: %m\n");
+			goto error;
+		}
+		buf = p;
+
+		read_size = alloc - size;
+		res = fread(buf + size, 1, read_size, stdin);
+		size += res;
+	} while (res == read_size);
+
+	if (ferror(stdin)) {
+		fprintf(stderr, "error: %m\n");
+		goto error;
+	}
+
+	err = process_json("-", buf, size);
+	free(buf);
+
+	return (err == 0) ? EXIT_SUCCESS : EXIT_FAILURE;
+
+error:
+	free(buf);
+	return EXIT_FAILURE;
+}
+
 int main(int argc, char *argv[])
 {
-	int fd, len, res, exit_code = EXIT_FAILURE;
+	int fd, res, exit_code = EXIT_FAILURE;
 	void *data;
 	struct stat sbuf;
-	struct spa_json it;
-	const char *value;
 
-	if (argc < 2) {
+	if (argc < 1) {
-		fprintf(stderr, "usage: %s <spa-json-file>\n", argv[0]);
+		fprintf(stderr, "usage: %s [spa-json-file]\n", argv[0]);
 		goto error;
 	}
+	if (argc == 1)
+		return process_stdin();
 	if ((fd = open(argv[1],  O_CLOEXEC | O_RDONLY)) < 0)  {
                 fprintf(stderr, "error opening file '%s': %m\n", argv[1]);
 		goto error;
@@ -119,24 +212,12 @@ int main(int argc, char *argv[])
                 goto error_close;
 	}
 
-	spa_json_init(&it, data, sbuf.st_size);
+	res = process_json(argv[1], data, sbuf.st_size);
-	if ((len = spa_json_next(&it, &value)) <= 0) {
+	if (res < 0)
-                fprintf(stderr, "not a valid file '%s': %s\n", argv[1], spa_strerror(len));
+		exit_code = EXIT_FAILURE;
-		goto error_unmap;
+	else
-	}
+		exit_code = EXIT_SUCCESS;
-	if (!spa_json_is_container(value, len)) {
-		spa_json_init(&it, data, sbuf.st_size);
-		value = "{";
-		len = 1;
-	}
-	if ((res = dump(stdout, 0, &it, value, len)) < 0) {
-                fprintf(stderr, "error parsing file '%s': %s\n", argv[1], spa_strerror(res));
-		goto error_unmap;
-	}
-	fprintf(stdout, "\n");
-	exit_code = EXIT_SUCCESS;
 
-error_unmap:
         munmap(data, sbuf.st_size);
 error_close:
         close(fd);