(UWP) Error if trying to use VFS on cores that don't support it

core.h

@@ -65,6 +65,8 @@ typedef struct rarch_system_info
    const char *input_desc_btn[MAX_USERS][RARCH_FIRST_META_KEY];
    char valid_extensions[255];
 
+   bool supports_vfs;
+
    struct retro_disk_control_callback  disk_control_cb;
    struct retro_location_callback      location_cb;
 

dynamic.c

@@ -1960,6 +1960,7 @@ bool rarch_environment_cb(unsigned cmd, void *data)
             RARCH_LOG("Core requested VFS version >= v%d, providing v%d\n", vfs_iface_info->required_interface_version, supported_vfs_version);
             vfs_iface_info->required_interface_version = supported_vfs_version;
             vfs_iface_info->iface                      = &vfs_iface;
+            system->supports_vfs = true;
          }
          else
          {

intl/msg_hash_us.h

@@ -4143,6 +4143,10 @@ MSG_HASH(
     MSG_ERROR_LIBRETRO_CORE_REQUIRES_SPECIAL_CONTENT,
     "Libretro core requires special content, but none were provided."
     )
+MSG_HASH(
+    MSG_ERROR_LIBRETRO_CORE_REQUIRES_VFS,
+    "Loading content from here requires VFS, but core does not support it"
+)
 MSG_HASH(
     MSG_ERROR_PARSING_ARGUMENTS,
     "Error parsing arguments."

libretro-common/vfs/vfs_implementation_uwp.cpp

@@ -49,6 +49,7 @@ using namespace Windows::Storage::FileProperties;
 #include <verbosity.h>
 #include <string/stdstring.h>
 #include <retro_environment.h>
+#include <uwp/uwp_func.h>
 
 namespace
 {
@@ -603,3 +604,14 @@ int retro_vfs_closedir_impl(libretro_vfs_implementation_dir *rdir)
 	free(rdir);
 	return 0;
 }
+
+bool uwp_is_path_accessible_using_standard_io(char *path)
+{
+	char *relative_path_abbrev = (char*)malloc(PATH_MAX_LENGTH * sizeof(char));
+	fill_pathname_abbreviate_special(relative_path_abbrev, path, PATH_MAX_LENGTH * sizeof(char));
+
+	bool result = strlen(relative_path_abbrev) >= 2 && (relative_path_abbrev[0] == ':' || relative_path_abbrev[0] == '~') && path_char_is_slash(relative_path_abbrev[1]);
+
+	free(relative_path_abbrev);
+	return result;
+}

msg_hash.h

@@ -260,6 +260,7 @@ enum msg_hash_enums
    MSG_COMPILED_AGAINST_API,
    MSG_ERROR_LIBRETRO_CORE_REQUIRES_SPECIAL_CONTENT,
    MSG_ERROR_LIBRETRO_CORE_REQUIRES_CONTENT,
+   MSG_ERROR_LIBRETRO_CORE_REQUIRES_VFS,
    MSG_SEVERAL_PATCHES_ARE_EXPLICITLY_DEFINED,
    MSG_DID_NOT_FIND_A_VALID_CONTENT_PATCH,
    MSG_FAILED_TO_ALLOCATE_MEMORY_FOR_PATCHED_CONTENT,

tasks/task_content.c

@@ -39,6 +39,10 @@
 #endif
 #endif
 
+#ifdef __WINRT__
+#include <uwp/uwp_func.h>
+#endif
+
 #ifdef HAVE_CONFIG_H
 #include "../config.h"
 #endif
@@ -557,6 +561,7 @@ static bool content_file_load(
    retro_ctx_load_content_info_t load_info;
    size_t msg_size = 1024 * sizeof(char);
    char *msg       = (char*)malloc(msg_size);
+   rarch_system_info_t *system = runloop_get_system_info();
 
    msg[0]          = '\0';
 
@@ -605,7 +610,6 @@ static bool content_file_load(
       }
       else
       {
-
 #ifdef HAVE_COMPRESSION
          if (     !content_ctx->block_extract
                && need_fullpath
@@ -617,6 +621,21 @@ static bool content_file_load(
                   error_string))
             goto error;
 #endif
+
+#ifdef __WINRT__
+         /* TODO: When support for the 'actual' VFS is added, there will need to be some more logic here */
+         if (!system->supports_vfs && !uwp_is_path_accessible_using_standard_io(path))
+         {
+            strlcpy(msg,
+               msg_hash_to_str(MSG_ERROR_LIBRETRO_CORE_REQUIRES_VFS),
+               msg_size
+            );
+            *error_string = strdup(msg);
+            goto error;
+         }
+#endif
+
+
          RARCH_LOG("%s\n", msg_hash_to_str(MSG_CONTENT_LOADING_SKIPPED_IMPLEMENTATION_WILL_DO_IT));
          content_rom_crc = file_crc32(0, path);
          RARCH_LOG("CRC32: 0x%x .\n", (unsigned)content_rom_crc);

uwp/uwp_func.h

@@ -27,6 +27,7 @@ extern char uwp_dir_data[PATH_MAX_LENGTH];
 extern char uwp_device_family[128];
 
 void uwp_open_broadfilesystemaccess_settings(void);
+bool uwp_is_path_accessible_using_standard_io(char *path);
 
 void* uwp_get_corewindow(void);