Core info list iteration was calling path_stat two times on the same

paths - unnecessary file I/O is an issue with UWP/WinRT so let's cut
this down to only one path_stat. config_file_read function created -
acts the same as config_file_new except it doesn't check if the path
provided is actually a directory, which in turn would lead to another path_stat call

core_info.c

@@ -286,7 +286,7 @@ static core_info_list_t *core_info_list_new(const char *path,
          char *tmp           = NULL;
          bool tmp_bool       = false;
          unsigned count      = 0;
-         config_file_t *conf = config_file_new(info_path);
+         config_file_t *conf = config_file_read(info_path);
 
          free(info_path);
 

libretro-common/file/config_file.c

@@ -69,7 +69,7 @@ struct config_include_list
 };
 
 static config_file_t *config_file_new_internal(
-      const char *path, unsigned depth, config_file_cb_t *cb);
+      const char *path, unsigned depth, config_file_cb_t *cb, bool no_checks);
 
 static int config_sort_compare_func(struct config_entry_list *a,
       struct config_entry_list *b)
@@ -270,7 +270,8 @@ static void add_child_list(config_file_t *parent, config_file_t *child)
       parent->tail = NULL;
 }
 
-static void add_sub_conf(config_file_t *conf, char *path, config_file_cb_t *cb)
+static void add_sub_conf(config_file_t *conf, char *path, config_file_cb_t *cb,
+      bool no_checks)
 {
    char real_path[PATH_MAX_LENGTH];
    config_file_t         *sub_conf  = NULL;
@@ -317,7 +318,7 @@ static void add_sub_conf(config_file_t *conf, char *path, config_file_cb_t *cb)
 #endif
 
    sub_conf = (config_file_t*)
-      config_file_new_internal(real_path, conf->include_depth + 1, cb);
+      config_file_new_internal(real_path, conf->include_depth + 1, cb, no_checks);
    if (!sub_conf)
       return;
 
@@ -327,18 +328,14 @@ static void add_sub_conf(config_file_t *conf, char *path, config_file_cb_t *cb)
 }
 
 static bool parse_line(config_file_t *conf,
-      struct config_entry_list *list, char *line, config_file_cb_t *cb)
+      struct config_entry_list *list, char *line, config_file_cb_t *cb,
+      bool no_checks)
 {
-   char *comment   = NULL;
    char *key_tmp   = NULL;
    size_t cur_size = 8;
    size_t idx      = 0;
    char *key       = (char*)malloc(9);
-
-   if (!key)
-      return false;
-
-   comment = strip_comment(line);
+   char *comment   = strip_comment(line);
 
    /* Starting line with #include includes config files. */
    if (comment == line)
@@ -354,7 +351,7 @@ static bool parse_line(config_file_t *conf,
             if (conf->include_depth >= MAX_INCLUDE_DEPTH)
                fprintf(stderr, "!!! #include depth exceeded for config. Might be a cycle.\n");
             else
-               add_sub_conf(conf, path, cb);
+               add_sub_conf(conf, path, cb, no_checks);
             free(path);
          }
          goto error;
@@ -399,7 +396,7 @@ error:
 }
 
 static config_file_t *config_file_new_internal(
-      const char *path, unsigned depth, config_file_cb_t *cb)
+      const char *path, unsigned depth, config_file_cb_t *cb, bool no_checks)
 {
    RFILE              *file = NULL;
    struct config_file *conf = (struct config_file*)malloc(sizeof(*conf));
@@ -417,8 +414,9 @@ static config_file_t *config_file_new_internal(
    if (!path || !*path)
       return conf;
 #if !defined(ORBIS)
-   if (path_is_directory(path))
-      goto error;
+   if (!no_checks)
+      if (path_is_directory(path))
+         goto error;
 #endif
    conf->path          = strdup(path);
    if (!conf->path)
@@ -460,7 +458,7 @@ static config_file_t *config_file_new_internal(
          continue;
       }
 
-      if (*line && parse_line(conf, list, line, cb))
+      if (*line && parse_line(conf, list, line, cb, no_checks))
       {
          if (conf->entries)
             conf->tail->next = list;
@@ -550,8 +548,9 @@ bool config_append_file(config_file_t *conf, const char *path)
 config_file_t *config_file_new_from_string(const char *from_string)
 {
    size_t i;
+   bool no_checks            = false;
    struct string_list *lines = NULL;
-   struct config_file *conf = (struct config_file*)malloc(sizeof(*conf));
+   struct config_file *conf  = (struct config_file*)malloc(sizeof(*conf));
    if (!conf)
       return NULL;
 
@@ -589,7 +588,7 @@ config_file_t *config_file_new_from_string(const char *from_string)
 
       if (line && conf)
       {
-         if (*line && parse_line(conf, list, line, NULL))
+         if (*line && parse_line(conf, list, line, NULL, no_checks))
          {
             if (conf->entries)
                conf->tail->next = list;
@@ -611,11 +610,16 @@ config_file_t *config_file_new_from_string(const char *from_string)
 
 config_file_t *config_file_new_with_callback(const char *path, config_file_cb_t *cb)
 {
-   return config_file_new_internal(path, 0, cb);
+   return config_file_new_internal(path, 0, cb, false);
 }
 config_file_t *config_file_new(const char *path)
 {
-   return config_file_new_internal(path, 0, NULL);
+   return config_file_new_internal(path, 0, NULL, false);
+}
+
+config_file_t *config_file_read(const char *path)
+{
+   return config_file_new_internal(path, 0, NULL, true);
 }
 
 static struct config_entry_list *config_get_entry(const config_file_t *conf,

libretro-common/include/file/config_file.h

@@ -86,6 +86,11 @@ typedef struct config_file_cb config_file_cb_t ;
  * NULL path will create an empty config file. */
 config_file_t *config_file_new(const char *path);
 
+/* Is the same as config_file_new, with the only difference that
+ * it doesn't check if the path provided is a directory. This can
+ * be significantly faster on platforms where file I/O is slow */
+config_file_t *config_file_read(const char *path);
+
 /* Loads a config file. Returns NULL if file doesn't exist.
  * NULL path will create an empty config file.
  * Includes cb callbacks to run custom code during config file processing.*/