How to programmatically find buffer visiting specific directory

Question

I'm looking for something similar to (find-buffer-visiting FILENAME &optional PREDICATE) that would find a dired-mode buffer visiting a specified directory. Something like:

(find-buffer-visiting-dir DIRNAME)

The built-in find-buffer-visiting only searches buffer visiting files quite unfortunately. It checks if the buffer has a local buffer-file-name variable bound. The optional PREDICATE is therefore used only on files.

A potential improvement for that function would be to write (find-buffer-visiting FILENAME &optional PREDICATE FILTER) where FILTER would be a filter function used on all buffers to determine if the buffer should be included in the search.

Is there something like this already available?

Answer 1

Sounds like you're looking for function dired-buffers-for-dir.

Dired+ enhances this function, but even the vanilla Emacs version is OK. C-h f dired-buffers-for-dir tells you (this is the Dired+ doc string):

dired-buffers-for-dir is a compiled Lisp function in dired+.el.

(dired-buffers-for-dir DIR &optional FILE SUBDIRS-P)

Return a list of buffers that Dired DIR (top level or in-situ subdir).

DIR is automatically expanded with expand-file-name using the default-directory. If you need expansion relative to some other directory then do that before calling dired-buffers-for-dir.

If FILE is non-nil, include only those whose wildcard pattern (if any) matches FILE.

If SUBDIRS-P is non-nil, also include the Dired buffers of directories below DIR.

The list is in reverse order of buffer creation, most recent last. As a side effect, killed Dired buffers for DIR are removed from dired-buffers.

In general, if it seems like there should be a utility function for dealing with files or directories, or their names etc., then it's likely that there is in fact such a function. Remember that the apropos commands are your friends. In this case, just M-x apropos dired buffer shows you this function (and others).