st/prober: Refactor JSON config loading so that we print less errors when we don't need the config

src/xrt/state_trackers/prober/p_json.c

@@ -43,30 +43,48 @@ read_content(FILE *file)
 	return buffer;
 }
 
-cJSON *
-p_json_open_or_create_main_file(void)
+void
+p_json_open_or_create_main_file(struct prober *p)
 {
+	char tmp[1024];
+	ssize_t ret =
+	    u_file_get_path_in_config_dir("config_v0.json", tmp, sizeof(tmp));
+	if (ret <= 0) {
+		fprintf(stderr,
+		        "ERROR:Could not load or create config file no $HOME "
+		        "or $XDG_CONFIG_HOME env variables defined\n");
+		return;
+	}
+
 	FILE *file = u_file_open_file_in_config_dir("config_v0.json", "r");
 	if (file == NULL) {
-		fprintf(stderr, "Could not open the file!\n");
-		return NULL;
+		return;
 	}
 
+	p->json.file_loaded = true;
+
 	char *str = read_content(file);
 	fclose(file);
 	if (str == NULL) {
-		fprintf(stderr, "Could not read the contents of the file!\n");
-		return NULL;
+		fprintf(stderr, "ERROR: Could not read the contents of '%s'!\n",
+		        tmp);
+		return;
 	}
 
-	cJSON *ret = cJSON_Parse(str);
-	if (ret == NULL) {
-		fprintf(stderr, "Failed to parse JSON:\n%s\n#######\n", str);
+	// No config created, ignore.
+	if (strlen(str) == 0) {
+		free(str);
+		return;
+	}
+
+	p->json.root = cJSON_Parse(str);
+	if (p->json.root == NULL) {
+		fprintf(stderr, "Failed to parse JSON in '%s':\n%s\n#######\n",
+		        tmp, str);
 		fprintf(stderr, "'%s'\n", cJSON_GetErrorPtr());
 	}
 
 	free(str);
-	return ret;
 }
 
 static cJSON *
@@ -128,15 +146,20 @@ get_obj_str(cJSON *json, const char *name, char *array, size_t array_size)
 }
 
 bool
-p_json_get_tracking_settings(cJSON *root, struct xrt_settings_tracking *s)
+p_json_get_tracking_settings(struct prober *p, struct xrt_settings_tracking *s)
 {
-	if (root == NULL) {
+	if (p->json.root == NULL) {
+		if (p->json.file_loaded) {
+			fprintf(stderr, "JSON not parsed!\n");
+		} else {
+			fprintf(stderr, "No config file!\n");
+		}
 		return false;
 	}
 
-	cJSON *t = cJSON_GetObjectItemCaseSensitive(root, "tracking");
+	cJSON *t = cJSON_GetObjectItemCaseSensitive(p->json.root, "tracking");
 	if (t == NULL) {
-		fprintf(stderr, "No tracking node!\n");
+		fprintf(stderr, "No tracking node\n");
 		return false;
 	}
 

src/xrt/state_trackers/prober/p_prober.c

@@ -328,7 +328,7 @@ initialize(struct prober *p, struct xrt_prober_entry_lists *lists)
 
 	int ret;
 
-	p->json.root = p_json_open_or_create_main_file();
+	p_json_open_or_create_main_file(p);
 
 	ret = collect_entries(p);
 	if (ret != 0) {

src/xrt/state_trackers/prober/p_prober.h

@@ -135,6 +135,9 @@ struct prober
 
 	struct
 	{
+		//! For error reporting, was it loaded but not parsed?
+		bool file_loaded;
+
 		cJSON *root;
 	} json;
 
@@ -178,14 +181,14 @@ struct prober
 /*!
  * Load the JSON config file.
  */
-cJSON *
-p_json_open_or_create_main_file(void);
+void
+p_json_open_or_create_main_file(struct prober *p);
 
 /*!
  * Extract tracking settings from the JSON.
  */
 bool
-p_json_get_tracking_settings(cJSON *root, struct xrt_settings_tracking *s);
+p_json_get_tracking_settings(struct prober *p, struct xrt_settings_tracking *s);
 
 /*!
  * Dump the given device to stdout.

src/xrt/state_trackers/prober/p_tracking.c

@@ -40,8 +40,8 @@ struct p_factory
 	// Owning prober.
 	struct prober *p;
 
-	// Has the settings be loaded.
-	bool setting_ok;
+	// Have we tried to load the settings.
+	bool tried_settings;
 
 	// Settings for this tracking system.
 	struct xrt_settings_tracking settings;
@@ -112,13 +112,23 @@ on_video_device(struct xrt_prober *xp,
 static void
 p_factory_ensure_frameserver(struct p_factory *fact)
 {
-	// No settings loaded.
-	if (!fact->setting_ok) {
+	// Already created.
+	if (fact->xfs != NULL) {
 		return;
 	}
 
-	// Already created.
-	if (fact->xfs != NULL) {
+	// We have already tried to load the settings.
+	if (fact->tried_settings) {
+		return;
+	}
+
+	// We have no tried the settings.
+	fact->tried_settings = true;
+
+	if (!p_json_get_tracking_settings(fact->p, &fact->settings)) {
+		fprintf(stderr,
+		        "ERROR: Could not setup PSVR and/or PSMV tracking, see "
+		        "above.\n");
 		return;
 	}
 
@@ -217,23 +227,21 @@ p_factory_create_tracked_psmv(struct xrt_tracking_factory *xfact,
 {
 	struct p_factory *fact = p_factory(xfact);
 
-	if (!fact->setting_ok) {
-		return -1;
-	}
-
 #ifdef XRT_HAVE_OPENCV
 	struct xrt_tracked_psmv *xtmv = NULL;
 
 	p_factory_ensure_frameserver(fact);
 
 	if (fact->num_xtmv < ARRAY_SIZE(fact->xtmv)) {
-		xtmv = fact->xtmv[fact->num_xtmv++];
+		xtmv = fact->xtmv[fact->num_xtmv];
 	}
 
 	if (xtmv == NULL) {
 		return -1;
 	}
 
+	fact->num_xtmv++;
+
 	t_psmv_start(xtmv);
 	*out_xtmv = xtmv;
 
@@ -250,10 +258,6 @@ p_factory_create_tracked_psvr(struct xrt_tracking_factory *xfact,
 {
 	struct p_factory *fact = p_factory(xfact);
 
-	if (!fact->setting_ok) {
-		return -1;
-	}
-
 #ifdef XRT_HAVE_OPENCV
 	struct xrt_tracked_psvr *xtvr = NULL;
 
@@ -306,13 +310,6 @@ p_tracking_init(struct prober *p)
 	// Finally set us as the tracking factory.
 	p->base.tracking = &fact->base;
 
-	fact->setting_ok =
-	    p_json_get_tracking_settings(p->json.root, &fact->settings);
-
-	if (!fact->setting_ok) {
-		fprintf(stderr, "Failed to load settings!\n");
-	}
-
 	return 0;
 }