spa: add tool to dump spa json file to plain json

spa/tools/meson.build

@@ -7,3 +7,8 @@ executable('spa-monitor', 'spa-monitor.c',
            include_directories : [spa_inc],
            dependencies : [dl_lib, ],
            install : true)
+
+executable('spa-json-dump', 'spa-json-dump.c',
+           include_directories : [spa_inc],
+           dependencies : [dl_lib, ],
+           install : true)

spa/tools/spa-json-dump.c

@@ -0,0 +1,125 @@
+/* Simple Plugin API
+ *
+ * Copyright © 2021 Wim Taymans
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <errno.h>
+
+#include <spa/utils/result.h>
+#include <spa/utils/json.h>
+
+static int dump(FILE *file, int indent, struct spa_json *it, const char *value, int len)
+{
+	struct spa_json sub;
+	int count = 0;
+
+	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);
+		}
+		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);
+		while ((len = spa_json_next(&sub, &value)) > 0) {
+			char *q = spa_json_is_string(value, len) ? "" : "\"";
+			fprintf(file, "%s\n%*s%s%.*s%s: ", count++ > 0 ? "," : "",
+					indent+2, "", q, len, value, q);
+			if ((len = spa_json_next(&sub, &value)) <= 0)
+				break;
+			dump(file, indent+2, &sub, value, len);
+		}
+		fprintf(file, "%s%*s}", count > 0 ? "\n" : "",
+				count > 0 ? indent : 0, "");
+	} else if (spa_json_is_string(value, len) ||
+	    spa_json_is_null(value, len) ||
+	    spa_json_is_bool(value, len) ||
+	    spa_json_is_float(value, len)) {
+		fprintf(file, "%.*s", len, value);
+	} else {
+		fprintf(file, "\"%.*s\"", len, value);
+	}
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	int fd, len, res, exit_code = EXIT_FAILURE;
+	void *data;
+	struct stat sbuf;
+	struct spa_json it;
+	const char *value;
+
+	if (argc < 2) {
+		fprintf(stderr, "usage: %s <spa-json-file>\n", argv[0]);
+		goto error;
+	}
+	if ((fd = open(argv[1],  O_CLOEXEC | O_RDONLY)) < 0)  {
+                fprintf(stderr, "error opening file '%s': %m\n", argv[1]);
+		goto error;
+        }
+        if (fstat(fd, &sbuf) < 0) {
+                fprintf(stderr, "error statting file '%s': %m\n", argv[1]);
+                goto error_close;
+	}
+        if ((data = mmap(NULL, sbuf.st_size, PROT_READ, MAP_PRIVATE, fd, 0)) == MAP_FAILED) {
+                fprintf(stderr, "error mmaping file '%s': %m\n", argv[1]);
+                goto error_close;
+	}
+
+	spa_json_init(&it, data, sbuf.st_size);
+	if ((len = spa_json_next(&it, &value)) <= 0) {
+                fprintf(stderr, "not a valid file '%s': %s\n", argv[1], spa_strerror(len));
+		goto error_unmap;
+	}
+	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);
+error:
+	return exit_code;
+}