Add option to link files instead of moving or copying them.

beets/config_default.yaml

@@ -5,6 +5,7 @@ import:
     write: yes
     copy: yes
     move: no
+    link: no
     delete: no
     resume: ask
     incremental: no

beets/library.py

@@ -524,7 +524,7 @@ def try_sync(self, write=None):
 
     # Files themselves.
 
-    def move_file(self, dest, copy=False):
+    def move_file(self, dest, copy=False, link=False):
         """Moves or copies the item's file, updating the path value if
         the move succeeds. If a file exists at ``dest``, then it is
         slightly modified to be unique.
@@ -535,6 +535,10 @@ def move_file(self, dest, copy=False):
             util.copy(self.path, dest)
             plugins.send("item_copied", item=self, source=self.path,
                          destination=dest)
+        elif link:
+            util.link(self.path, dest)
+            plugins.send("item_linked", item=self, source=self.path,
+                         destination=dest)
         else:
             plugins.send("before_item_moved", item=self, source=self.path,
                          destination=dest)
@@ -814,7 +818,7 @@ def remove(self, delete=False, with_items=True):
             for item in self.items():
                 item.remove(delete, False)
 
-    def move_art(self, copy=False):
+    def move_art(self, copy=False, link=False):
         """Move or copy any existing album art so that it remains in the
         same directory as the items.
         """
@@ -832,6 +836,8 @@ def move_art(self, copy=False):
                           util.displayable_path(new_art)))
         if copy:
             util.copy(old_art, new_art)
+        elif link:
+            util.link(old_art, new_art)
         else:
             util.move(old_art, new_art)
         self.artpath = new_art

beets/util/__init__.py

@@ -449,6 +449,26 @@ def move(path, dest, replace=False):
                                   traceback.format_exc())
 
 
+def link(path, dest, replace=False):
+    """Create a symbolic link from path to `dest`. Raises an OSError if
+    `dest` already exists, unless `replace` is True. Does nothing if
+    `path` == `dest`."""
+    if (samefile(path, dest)):
+        return
+
+    path = syspath(path)
+    dest = syspath(dest)
+    if os.path.exists(dest) and not replace:
+        raise FilesystemError('file exists', 'rename', (path, dest),
+                              traceback.format_exc())
+    try:
+        os.symlink(path, dest)
+    except OSError:
+        raise FilesystemError('Operating system does not support symbolic '
+                              'links.', 'link', (path, dest),
+                              traceback.format_exc())
+
+
 def unique_path(path):
     """Returns a version of ``path`` that does not exist on the
     filesystem. Specifically, if ``path` itself already exists, then