When changing the title/author of a book, use hard links instead of copying the file, for a large speedup.

src/calibre/library/database2.py

@@ -646,7 +646,7 @@ def set_path(self, index, index_is_id=False):
         spath = os.path.join(self.library_path, *current_path.split('/'))
         tpath = os.path.join(self.library_path, *path.split('/'))
 
-        wam = WindowsAtomicFolderMove(spath) if iswindows else None
+        wam = WindowsAtomicFolderMove(spath) if iswindows and current_path else None
         try:
             if not os.path.exists(tpath):
                 os.makedirs(tpath)
@@ -1375,6 +1375,11 @@ def copy_format_to(self, index, fmt, dest, index_is_id=False,
                 if hasattr(dest, 'flush'):
                     dest.flush()
             elif dest and not samefile(dest, path):
+                try:
+                    os.link(path, dest)
+                    return
+                except:
+                    pass
                 with lopen(path, 'rb') as f, lopen(dest, 'wb') as d:
                     shutil.copyfileobj(f, d)
 

src/calibre/utils/filenames.py

@@ -300,6 +300,11 @@ def copy_path_to(self, path, dest):
         if handle is None:
             raise ValueError(u'The file %r did not exist when this move'
                     ' operation was started'%path)
+        try:
+            win32file.CreateHardLink(dest, path)
+            return
+        except:
+            pass
         with lopen(dest, 'wb') as f:
             while True:
                 hr, raw = win32file.ReadFile(handle, 1024*1024)