Improve FindAbsolutePath implementation

src/common/pathutil.c

@@ -1,24 +1,67 @@
 
 #include <stdlib.h>
 
-
 #if defined(_WIN32)
 #   include <windows.h>
+#   include "xmalloc.h"
 #endif
 
 #if defined(_WIN32)
 
-char *FindAbsolutePath (const char *path) {
-    return  _fullpath (NULL, path, MAX_PATH);
+char *FindAbsolutePath (const char *Path)
+/*
+** Determines the absolute path of the given relative path.
+** If the path points to a symlink, resolves such symlink.
+** The absolute path for the file is stored in a malloced buffer.
+** Returns NULL if some error occured.
+** The returned path's separator is system specific.
+*/
+{
+
+    HANDLE Handle = CreateFileA (Path,
+                                 FILE_READ_ATTRIBUTES,
+                                 FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                                 NULL,
+                                 OPEN_EXISTING,
+                                 FILE_FLAG_BACKUP_SEMANTICS,
+                                 NULL);
+
+    if (Handle == INVALID_HANDLE_VALUE) {
+        return NULL;
+    }
+
+    size_t BufferSize = MAX_PATH + 10;
+    char* Buffer = xmalloc(BufferSize);
+
+    DWORD Status = GetFinalPathNameByHandleA (Handle,
+                                              Buffer,
+                                              BufferSize,
+                                              FILE_NAME_NORMALIZED | VOLUME_NAME_DOS);
+
+    if (Status == 0) {
+        free(Buffer);
+        CloseHandle(Handle);
+        return NULL;
+    }
+
+    CloseHandle(Handle);
+
+    return Buffer;
 }
 
 #else
 
 extern char* realpath (const char* path, char* resolved_path);
 
-/* this uses the POSIX1.-2008 version of the function,
-   which solves the problem of finding a maximum path length for the file */
-char* FindAbsolutePath (const char* path) {
+char* FindAbsolutePath (const char* path)
+/*
+** Determines the absolute path of the given relative path.
+** If the path points to a symlink, resolves such symlink.
+** The absolute path for the file is stored in a malloced buffer.
+** Returns NULL if some error occured.
+** The returned path's separator is system specific.
+*/
+{
     return realpath (path, NULL);
 }
 

src/common/pathutil.h

@@ -41,14 +41,14 @@
 /*****************************************************************************/
 
 
-/**
- * Determines the absolute path of the given relative path.
- * The absolute path for the file is stored in a malloced buffer.
- * Returns NULL if some error occured.
- * The returned path's separator is system specific.
- */
 char *FindAbsolutePath (const char *path);
-
+/*
+** Determines the absolute path of the given relative path.
+** If the path points to a symlink, resolves such symlink.
+** The absolute path for the file is stored in a malloced buffer.
+** Returns NULL if some error occured.
+** The returned path's separator is system specific.
+*/
 
 
 /* End of pathutil.h */