From 5abd8251370da46c2afb5f4477d8424f6324ce30 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Tue, 1 Jan 2019 23:25:36 +0100
Subject: [PATCH] yml: yml_load(): optionally allocates an error string (on
 error)

---
 main.c |  3 ++-
 yml.c  | 27 +++++++++++++++++++++------
 yml.h  |  2 +-
 3 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/main.c b/main.c
index eda7269..40e0f8f 100644
--- a/main.c
+++ b/main.c
@@ -62,7 +62,8 @@ main(int argc, const char *const *argv)
     if (conf_file == NULL)
         return 1;
 
-    struct yml_node *conf = yml_load(conf_file);
+    char *yml_error;
+    struct yml_node *conf = yml_load(conf_file, &yml_error);
     fclose(conf_file);
 
     if (conf == NULL)
diff --git a/yml.c b/yml.c
index 27e1c5c..1d27552 100644
--- a/yml.c
+++ b/yml.c
@@ -215,7 +215,7 @@ post_process(struct yml_node *node)
 }
 
 struct yml_node *
-yml_load(FILE *yml)
+yml_load(FILE *yml, char **error)
 {
     yaml_parser_t yaml;
     yaml_parser_initialize(&yaml);
@@ -238,11 +238,26 @@ yml_load(FILE *yml)
     while (!done) {
         yaml_event_t event;
         if (!yaml_parser_parse(&yaml, &event)) {
-            //printf("yaml parser error\n");
-            /* TODO: free node tree */
-            root = NULL;
-            assert(false);
-            break;
+            if (error != NULL) {
+                int cnt = snprintf(
+                    NULL, 0, "%zu:%zu: %s %s",
+                    yaml.problem_mark.line,
+                    yaml.problem_mark.column,
+                    yaml.problem,
+                    yaml.context != NULL ? yaml.context : "");
+
+                *error = malloc(cnt + 1);
+                snprintf(*error, cnt + 1, "%zu:%zu: %s %s",
+                    yaml.problem_mark.line,
+                    yaml.problem_mark.column,
+                    yaml.problem,
+                    yaml.context != NULL ? yaml.context : "");
+                (*error)[cnt] = '\0';
+            }
+
+            yml_destroy(root);
+            yaml_parser_delete(&yaml);
+            return NULL;
         }
 
         switch (event.type) {
diff --git a/yml.h b/yml.h
index b079b58..51ec58c 100644
--- a/yml.h
+++ b/yml.h
@@ -4,7 +4,7 @@
 
 struct yml_node;
 
-struct yml_node *yml_load(FILE *yml);
+struct yml_node *yml_load(FILE *yml, char **error);
 void yml_destroy(struct yml_node *root);
 
 bool yml_is_scalar(const struct yml_node *node);