Introduce plat_file_check and use it for ROM existence checking

src/include/86box/plat.h

@@ -150,6 +150,7 @@ extern void     plat_get_temp_dir(char *outbuf, uint8_t len);
 extern void     plat_get_vmm_dir(char *outbuf, size_t len);
 extern void     plat_init_rom_paths(void);
 extern int      plat_dir_check(char *path);
+extern int      plat_file_check(const char *path);
 extern int      plat_dir_create(char *path);
 extern void    *plat_mmap(size_t size, uint8_t executable);
 extern void     plat_munmap(void *ptr, size_t size);

src/mem/rom.c

@@ -28,6 +28,7 @@
 #include <string.h>
 #include <stdlib.h>
 #include <wchar.h>
+#include <stdbool.h>
 #define HAVE_STDARG_H
 #include <86box/86box.h>
 #include "cpu.h"
@@ -129,6 +130,34 @@ rom_get_full_path(char *dest, const char *fn)
     }
 }
 
+bool
+rom_fcheck(const char *fn)
+{
+    char temp[1024];
+    bool exists = false;
+
+    if (fn == NULL)
+        return false;
+    
+    if (strstr(fn, "roms/") == fn) {
+        /* Relative path */
+        for (rom_path_t *rom_path = &rom_paths; rom_path != NULL; rom_path = rom_path->next) {
+            path_append_filename(temp, rom_path->path, fn + 5);
+
+            exists = plat_file_check(temp);
+
+            if (exists) {
+                return exists;
+            }
+        }
+
+        return exists;
+    } else {
+        /* Absolute path */
+        return plat_file_check(fn);
+    }
+}
+
 FILE *
 rom_fopen(const char *fn, char *mode)
 {
@@ -186,15 +215,7 @@ rom_getfile(char *fn, char *s, int size)
 int
 rom_present(const char *fn)
 {
-    FILE *fp;
-
-    fp = rom_fopen(fn, "rb");
-    if (fp != NULL) {
-        (void) fclose(fp);
-        return 1;
-    }
-
-    return 0;
+    return rom_fcheck(fn);
 }
 
 uint8_t

src/qt/qt_platform.cpp

@@ -64,6 +64,8 @@
 #    include <sys/mman.h>
 #endif
 
+#include <sys/stat.h>
+
 #ifdef Q_OS_OPENBSD
 #    include <pthread_np.h>
 #endif
@@ -250,6 +252,22 @@ plat_dir_check(char *path)
     return fi.isDir() ? 1 : 0;
 }
 
+int
+plat_file_check(const char *path)
+{
+#ifdef _WIN32
+    auto data = QString::fromUtf8(path).toStdWString();
+    auto res = GetFileAttributesW(data.c_str());
+    return (res != INVALID_FILE_ATTRIBUTES && !(res & FILE_ATTRIBUTE_DIRECTORY));
+#else
+    struct stat dummy;
+    if (stat(path, &dummy) < 0) {
+        return 0;
+    }
+    return !S_ISDIR(dummy.st_mode);
+#endif
+}
+
 int
 plat_getcwd(char *bufp, int max)
 {

src/unix/unix.c

@@ -412,6 +412,16 @@ plat_dir_check(char *path)
     return S_ISDIR(dummy.st_mode);
 }
 
+int
+plat_file_check(const char *path)
+{
+    struct stat dummy;
+    if (stat(path, &dummy) < 0) {
+        return 0;
+    }
+    return !S_ISDIR(dummy.st_mode);
+}
+
 int
 plat_dir_create(char *path)
 {