Make json_error_t opaque

All decoding functions now accept a json_error_t** parameter and set
it to point to a heap-allocated json_error_t structure if an error
occurs. The contents of json_error_t are no longer exposed directly, a
few functions to do it have been added instead. If an error occurs,
the user must free the json_error_t value.

This makes it possible to enhance the error reporting facilities in
the future without breaking ABI compatibility with older versions.

This is a backwards incompatible change.

test/bin/json_process.c

@@ -31,7 +31,7 @@ int main(int argc, char *argv[])
     size_t flags = 0;
 
     json_t *json;
-    json_error_t error;
+    json_error_t *error;
 
     if(argc != 1) {
         fprintf(stderr, "usage: %s\n", argv[0]);
@@ -61,7 +61,10 @@ int main(int argc, char *argv[])
 
     json = json_loadf(stdin, 0, &error);
     if(!json) {
-        fprintf(stderr, "%d\n%s\n", error.line, error.text);
+        fprintf(stderr, "%d\n%s\n",
+                json_error_line(error),
+                json_error_msg(error));
+        free(error);
         return 1;
     }
 

test/suites/api/check-exports

@@ -47,6 +47,8 @@ json_object_iter_set_new
 json_dumps
 json_dumpf
 json_dump_file
+json_error_line
+json_error_msg
 json_loads
 json_loadf
 json_load_file

test/suites/api/test_load.c

@@ -12,13 +12,16 @@
 int main()
 {
     json_t *json;
-    json_error_t error;
+    json_error_t *error;
 
     json = json_load_file("/path/to/nonexistent/file.json", 0, &error);
-    if(error.line != -1)
+    if(json)
+      fail("json_load didn't return an error!");
+    if(json_error_line(error) != -1)
         fail("json_load_file returned an invalid line number");
-    if(strcmp(error.text, "unable to open /path/to/nonexistent/file.json: No such file or directory") != 0)
+    if(strcmp(json_error_msg(error), "unable to open /path/to/nonexistent/file.json: No such file or directory") != 0)
         fail("json_load_file returned an invalid error message");
 
+    free(error);
     return 0;
 }