create_buffer

Create a GTK buffer for the file.

Creates a GtkSourceFileBuffer instance and stores it in file.buffer. If file.buffer already exists and is a GtkSourceFileBuffer, returns early.

Process

1. Cleanup old buffers before creating new one

   2. Get language object if available (from file.language)

   3. Create GtkSourceFileBuffer (extends GtkSource.Buffer directly)

   4. Store in file.buffer property

The buffer will have syntax highlighting if language is available.

Parameters: