Subject: [bug#54180] [PATCH 02/12] home: symlink-manager: Move helper procedures as top-level defines.

From: Ludovic Courtès <[email-masked]>
Date: Sun, 27 Feb 2022 14:53:32 +0100

* gnu/home/services/symlink-manager.scm (update-symlinks-script): Remove
'config-home', which is unused.  Move 'home-path', 'backup-dir',
'get-target-path', 'get-backup-path', 'directory?', 'empty-directory?',
'symlink-to-store?', and 'backup-file' to the top level.  Move
'create-symlinks' and 'cleanup-symlinks' to the top level as well, and
add parameters.  Adjust callers.
---
 gnu/home/services/symlink-manager.scm | 240 +++++++++++++-------------
 1 file changed, 116 insertions(+), 124 deletions(-)

diff --git a/gnu/home/services/symlink-manager.scm b/gnu/home/services/symlink-manager.scm
index c60cdcffb7..25470209d1 100644
--- a/gnu/home/services/symlink-manager.scm
+++ b/gnu/home/services/symlink-manager.scm
@@ -88,12 +88,121 @@ (define ((file-tree-traverse preordering) node)
                  (list (cons 'dir path))
                  (append-map (file-tree-traverse preordering) rest))))))
 
+         (define home-path
+           (getenv "HOME"))
+
+         (define backup-dir
+           (string-append home-path "/" (number->string (current-time))
+                          "-guix-home-legacy-configs-backup"))
+
+         (define (get-target-path path)
+           (string-append home-path "/." path))
+
+         (define (get-backup-path path)
+           (string-append backup-dir "/." path))
+
+         (define (directory? path)
+           (equal? (stat:type (stat path)) 'directory))
+
+         (define (empty-directory? dir)
+           (equal? (scandir dir) '("." "..")))
+
+         (define (symlink-to-store? path)
+           (and (equal? (stat:type (lstat path)) 'symlink)
+                (store-file-name? (readlink path))))
+
+         (define (backup-file path)
+           (mkdir-p backup-dir)
+           (format #t (G_ "Backing up ~a...") (get-target-path path))
+           (mkdir-p (dirname (get-backup-path path)))
+           (rename-file (get-target-path path) (get-backup-path path))
+           (display (G_ " done\n")))
+
+         (define (cleanup-symlinks old-tree)
+           ;; Delete from directory OLD-TREE symlinks that correspond to a
+           ;; previous generation.
+           (let ((to-delete ((file-tree-traverse #f) old-tree)))
+             (display
+              (G_
+               "Cleaning up symlinks from previous home-environment.\n\n"))
+             (map
+              (match-lambda
+                (('dir . ".")
+                 (display (G_ "Cleanup finished.\n\n")))
+
+                (('dir . path)
+                 (if (and
+                      (file-exists? (get-target-path path))
+                      (directory? (get-target-path path))
+                      (empty-directory? (get-target-path path)))
+                     (begin
+                       (format #t (G_ "Removing ~a...")
+                               (get-target-path path))
+                       (rmdir (get-target-path path))
+                       (display (G_ " done\n")))
+                     (format
+                      #t
+                      (G_ "Skipping ~a (not an empty directory)... done\n")
+                      (get-target-path path))))
+
+                (('file . path)
+                 (when (file-exists? (get-target-path path))
+                   ;; DO NOT remove the file if it is no longer a symlink to
+                   ;; the store, it will be backed up later during
+                   ;; create-symlinks phase.
+                   (if (symlink-to-store? (get-target-path path))
+                       (begin
+                         (format #t (G_ "Removing ~a...") (get-target-path path))
+                         (delete-file (get-target-path path))
+                         (display (G_ " done\n")))
+                       (format
+                        #t
+                        (G_ "Skipping ~a (not a symlink to store)... done\n")
+                        (get-target-path path))))))
+              to-delete)))
+
+         (define (create-symlinks new-tree new-files-path)
+           ;; Create in directory NEW-TREE symlinks to the files under
+           ;; NEW-FILES-PATH, creating backups as needed.
+           (define (get-source-path path)
+             (readlink (string-append new-files-path "/" path)))
+
+           (let ((to-create ((file-tree-traverse #t) new-tree)))
+             (map
+              (match-lambda
+                (('dir . ".")
+                 (display
+                  (G_ "New symlinks to home-environment will be created soon.\n"))
+                 (format
+                  #t (G_ "All conflicting files will go to ~a.\n\n") backup-dir))
+
+                (('dir . path)
+                 (let ((target-path (get-target-path path)))
+                   (when (and (file-exists? target-path)
+                              (not (directory? target-path)))
+                     (backup-file path))
+
+                   (if (file-exists? target-path)
+                       (format
+                        #t (G_ "Skipping   ~a (directory already exists)... done\n")
+                        target-path)
+                       (begin
+                         (format #t (G_ "Creating   ~a...") target-path)
+                         (mkdir target-path)
+                         (display (G_ " done\n"))))))
+
+                (('file . path)
+                 (when (file-exists? (get-target-path path))
+                   (backup-file path))
+                 (format #t (G_ "Symlinking ~a -> ~a...")
+                         (get-target-path path) (get-source-path path))
+                 (symlink (get-source-path path) (get-target-path path))
+                 (display (G_ " done\n"))))
+              to-create)))
+
          #$%initialize-gettext
 
-         (let* ((config-home    (or (getenv "XDG_CONFIG_HOME")
-                                    (string-append (getenv "HOME") "/.config")))
-
-                (he-path (string-append (getenv "HOME") "/.guix-home"))
+         (let* ((he-path (string-append (getenv "HOME") "/.guix-home"))
                 (new-he-path (string-append he-path ".new"))
                 (new-home (getenv "GUIX_NEW_HOME"))
                 (old-home (getenv "GUIX_OLD_HOME"))
@@ -103,141 +212,24 @@ (define ((file-tree-traverse preordering) node)
                 ;; to make file-system-tree works it should be a directory.
                 (new-files-dir-path (string-append new-files-path "/."))
 
-                (home-path (getenv "HOME"))
-                (backup-dir (string-append home-path "/"
-                                           (number->string (current-time))
-                                           "-guix-home-legacy-configs-backup"))
-
                 (old-tree (if old-home
                               ((simplify-file-tree "")
                                (file-system-tree
                                 (string-append old-home "/files/.")))
                               #f))
                 (new-tree ((simplify-file-tree "")
-                           (file-system-tree new-files-dir-path)))
-
-                (get-source-path
-                 (lambda (path)
-                   (readlink (string-append new-files-path "/" path))))
-
-                (get-target-path
-                 (lambda (path)
-                   (string-append home-path "/." path)))
-
-                (get-backup-path
-                 (lambda (path)
-                   (string-append backup-dir "/." path)))
-
-                (directory?
-                 (lambda (path)
-                   (equal? (stat:type (stat path)) 'directory)))
-
-                (empty-directory?
-                 (lambda (dir)
-                   (equal? (scandir dir) '("." ".."))))
-
-                (symlink-to-store?
-                 (lambda (path)
-                   (and
-                    (equal? (stat:type (lstat path)) 'symlink)
-                    (store-file-name? (readlink path)))))
-
-                (backup-file
-                 (lambda (path)
-                   (mkdir-p backup-dir)
-                   (format #t (G_ "Backing up ~a...") (get-target-path path))
-                   (mkdir-p (dirname (get-backup-path path)))
-                   (rename-file (get-target-path path) (get-backup-path path))
-                   (display (G_ " done\n"))))
-
-                (cleanup-symlinks
-                 (lambda ()
-                   (let ((to-delete ((file-tree-traverse #f) old-tree)))
-                     (display
-                      (G_
-                       "Cleaning up symlinks from previous home-environment.\n\n"))
-                     (map
-                      (match-lambda
-                        (('dir . ".")
-                         (display (G_ "Cleanup finished.\n\n")))
-
-                        (('dir . path)
-                         (if (and
-                              (file-exists? (get-target-path path))
-                              (directory? (get-target-path path))
-                              (empty-directory? (get-target-path path)))
-                             (begin
-                               (format #t (G_ "Removing ~a...")
-                                       (get-target-path path))
-                               (rmdir (get-target-path path))
-                               (display (G_ " done\n")))
-                             (format
-                              #t
-                              (G_ "Skipping ~a (not an empty directory)... done\n")
-                              (get-target-path path))))
-
-                        (('file . path)
-                         (when (file-exists? (get-target-path path))
-                           ;; DO NOT remove the file if it is no longer
-                           ;; a symlink to the store, it will be backed
-                           ;; up later during create-symlinks phase.
-                           (if (symlink-to-store? (get-target-path path))
-                               (begin
-                                 (format #t (G_ "Removing ~a...") (get-target-path path))
-                                 (delete-file (get-target-path path))
-                                 (display (G_ " done\n")))
-                               (format
-                                #t
-                                (G_ "Skipping ~a (not a symlink to store)... done\n")
-                                (get-target-path path))))))
-                      to-delete))))
-
-                (create-symlinks
-                 (lambda ()
-                   (let ((to-create ((file-tree-traverse #t) new-tree)))
-                     (map
-                      (match-lambda
-                        (('dir . ".")
-                         (display
-                          (G_ "New symlinks to home-environment will be created soon.\n"))
-                         (format
-                          #t (G_ "All conflicting files will go to ~a.\n\n") backup-dir))
-
-                        (('dir . path)
-                         (let ((target-path (get-target-path path)))
-                           (when (and (file-exists? target-path)
-                                      (not (directory? target-path)))
-                             (backup-file path))
-
-                           (if (file-exists? target-path)
-                               (format
-                                #t (G_ "Skipping   ~a (directory already exists)... done\n")
-                                target-path)
-                               (begin
-                                 (format #t (G_ "Creating   ~a...") target-path)
-                                 (mkdir target-path)
-                                 (display (G_ " done\n"))))))
-
-                        (('file . path)
-                         (when (file-exists? (get-target-path path))
-                           (backup-file path))
-                         (format #t (G_ "Symlinking ~a -> ~a...")
-                                 (get-target-path path) (get-source-path path))
-                         (symlink (get-source-path path) (get-target-path path))
-                         (display (G_ " done\n"))))
-                      to-create)))))
+                           (file-system-tree new-files-dir-path))))
 
            (when old-tree
-             (cleanup-symlinks))
+             (cleanup-symlinks old-tree))
 
-           (create-symlinks)
+           (create-symlinks new-tree new-files-path)
 
            (symlink new-home new-he-path)
            (rename-file new-he-path he-path)
 
            (display (G_" done\nFinished updating symlinks.\n\n")))))))
 
-
 (define (update-symlinks-gexp _)
   #~(primitive-load #$(update-symlinks-script)))
 
-- 
2.34.0