Restore cursor position after omnifunc call

Calling directly the omnifunc may move the cursor position. This is the case
with the default Vim omnifunc for C-family languages (ccomplete#Complete) which
calls searchdecl to find a declaration. This function is supposed to move the
cursor to the found declaration but it doesn't when called through the omni
completion mapping (CTRL-X CTRL-O). So, we restore the cursor position after
calling the omnifunc.

python/ycm/omni_completer.py

@@ -90,13 +90,22 @@ class OmniCompleter( Completer ):
       # because it affects the value returned by 'query'
       request_data[ 'start_column' ] = return_value + 1
 
+      # Calling directly the omnifunc may move the cursor position. This is the
+      # case with the default Vim omnifunc for C-family languages
+      # (ccomplete#Complete) which calls searchdecl to find a declaration. This
+      # function is supposed to move the cursor to the found declaration but it
+      # doesn't when called through the omni completion mapping (CTRL-X CTRL-O).
+      # So, we restore the cursor position after calling the omnifunc.
+      line, column = vimsupport.CurrentLineAndColumn()
+
       omnifunc_call = [ self._omnifunc,
                         "(0,'",
                         vimsupport.EscapeForVim( request_data[ 'query' ] ),
                         "')" ]
-
       items = vim.eval( ''.join( omnifunc_call ) )
 
+      vimsupport.SetCurrentLineAndColumn( line, column )
+
       if isinstance( items, dict ) and 'words' in items:
         items = items[ 'words' ]
 

python/ycm/vimsupport.py

@@ -56,6 +56,12 @@ def CurrentLineAndColumn():
   return line, column
 
 
+def SetCurrentLineAndColumn( line, column ):
+  """Sets the cursor position to the 0-based line and 0-based column."""
+  # Line from vim.current.window.cursor is 1-based.
+  vim.current.window.cursor = ( line + 1, column )
+
+
 def CurrentColumn():
   """Returns the 0-based current column. Do NOT access the CurrentColumn in
   vim.current.line. It doesn't exist yet when the cursor is at the end of the