Save all open files in current folder and subfolders

Question

Some of my projects are organised in way that the there isn't one make file at the top route of the project (git/svn/...) folder but I have several small Makefiles in subfolders of the project. Normally I use Projectile to save only files related to my current project and call the main Makefile but this doesn't work if the Makefiles are more distributed in the project.

I would like to have a function that saves all open/unsaved files from the current folder and it's subfolder and then run the Makefile in the current folder.

(defun max/save-compile-current-folder ()
    (interactive)
    (max/save-current-and-subfolder-files ...)
    (compile t))

I currently don't know how to write the function max/save-current-and-subfolder-files. I would appreciate any hints how to write this function or links to libraries that already implement it.

Answer 1

I just added this feature to helm-make. Give it a go and let me know if it works as you wanted, you just need to set the custom:

(setq helm-make-do-save t)

Here's the code that does it:

(when helm-make-do-save
  (let* ((regex (format "^%s" (regexp-quote default-directory)))
         (buffers
          (cl-remove-if-not
           (lambda (b)
             (let ((name (buffer-file-name b)))
               (and name
                    (string-match regex (expand-file-name name)))))
           (buffer-list))))
    (mapc
     (lambda (b)
       (with-current-buffer b
         (save-buffer)))
     buffers))) 

Answer 2

The simple thing would be to save everything with C-u C-x s (mnemonic: C-x s is a slightly awkward modification of C-x C-s which is the normal save command). The computer takes less time to save everything than you'd lose worrying what not to save. This runs the command save-some-buffers. With no prefix argument, you'll be prompted whether to save each modified buffer.

If you really want to save only some files, you can write a function that only saves files based on your chosen criteria.

(defun save-buffers-in-directory-tree (directory)
  "Save buffers that are visiting a file in the current directory and its children."
  (interactive (list default-directory))
  (setq directory (file-name-as-directory (file-truename directory)))
  (mapc (lambda (buffer)
          (let ((filename (buffer-file-name buffer)))
            (when (and (buffer-modified-p buffer) filename)
              (setq filename (file-truename filename))
              (when (string-prefix-p directory filename)
                (with-current-buffer buffer
                  (save-buffer))))))
        (buffer-list)))