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home: symlink-manager: 'create-symlinks' uses 'file-system-fold'.

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This removes the need for two intermediate representations of the file
tree.

* gnu/home/services/symlink-manager.scm (update-symlinks-script)
[simplify-file-tree, file-tree-traverse]: Remove.
[create-symlinks]: Rewrite in terms of 'file-system-fold'.
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Ludovic Courtès 2022-02-26 21:35:17 +01:00
parent 5fa188e92e
commit 1fb6ef0473
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1 changed files with 44 additions and 86 deletions
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130
gnu/home/services/symlink-manager.scm
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@ -43,52 +43,11 @@
(guix i18n))) (guix i18n)))
#~(begin #~(begin
(use-modules (ice-9 ftw) (use-modules (ice-9 ftw)
(ice-9 curried-definitions)
(ice-9 match) (ice-9 match)
(srfi srfi-1) (srfi srfi-1)
(guix i18n) (guix i18n)
(guix build utils)) (guix build utils))
(define ((simplify-file-tree parent) file)
"Convert the result produced by `file-system-tree' to less
verbose and more suitable for further processing format.
Extract dir/file info from stat and compose a relative path to the
root of the file tree.
Sample output:
((dir . \".\")
((dir . \"config\")
((dir . \"config/fontconfig\")
(file . \"config/fontconfig/fonts.conf\"))
((dir . \"config/isync\")
(file . \"config/isync/mbsyncrc\"))))
"
(match file
((name stat) `(file . ,(string-append parent name)))
((name stat children ...)
(cons `(dir . ,(string-append parent name))
(map (simplify-file-tree
(if (equal? name ".")
""
(string-append parent name "/")))
children)))))
(define ((file-tree-traverse preordering) node)
"Traverses the file tree in different orders, depending on PREORDERING.
if PREORDERING is @code{#t} resulting list will contain directories
before files located in those directories, otherwise directory will
appear only after all nested items already listed."
(let ((prepend (lambda (a b) (append b a))))
(match node
(('file . path) (list node))
((('dir . path) . rest)
((if preordering append prepend)
(list (cons 'dir path))
(append-map (file-tree-traverse preordering) rest))))))
(define home-path (define home-path
(getenv "HOME")) (getenv "HOME"))
@ -176,64 +135,63 @@ appear only after all nested items already listed."
(display (G_ "Cleanup finished.\n\n"))) (display (G_ "Cleanup finished.\n\n")))
(define (create-symlinks new-tree new-files-path) (define (create-symlinks home-generation)
;; Create in directory NEW-TREE symlinks to the files under ;; Create in $HOME symlinks for the files in HOME-GENERATION.
;; NEW-FILES-PATH, creating backups as needed. (define config-file-directory
;; Note: Trailing slash is needed because "files" is a symlink.
(string-append home-generation "/files/"))
(define (strip file)
(string-drop file
(+ 1 (string-length config-file-directory))))
(define (get-source-path path) (define (get-source-path path)
(readlink (string-append new-files-path "/" path))) (readlink (string-append config-file-directory path)))
(let ((to-create ((file-tree-traverse #t) new-tree))) (file-system-fold
(for-each (const #t) ;enter?
(match-lambda (lambda (file stat result) ;leaf
(('dir . ".") (let ((source (get-source-path (strip file)))
(display (target (get-target-path (strip file))))
(G_ "New symlinks to home-environment will be created soon.\n")) (when (file-exists? target)
(format (backup-file (strip file)))
#t (G_ "All conflicting files will go to ~a.\n\n") backup-dir)) (format #t (G_ "Symlinking ~a -> ~a...")
target source)
(symlink source target)
(display (G_ " done\n"))))
(lambda (directory stat result) ;down
(unless (string=? directory config-file-directory)
(let ((target (get-target-path (strip directory))))
(when (and (file-exists? target)
(not (file-is-directory? target)))
(backup-file (strip directory)))
(('dir . path) (catch 'system-error
(let ((target-path (get-target-path path))) (lambda ()
(when (and (file-exists? target-path) (mkdir target))
(not (file-is-directory? target-path))) (lambda args
(backup-file path)) (let ((errno (system-error-errno args)))
(unless (= EEXIST errno)
(if (file-exists? target-path) (format #t (G_ "failed to create directory ~a: ~s~%")
(format target (strerror errno))
#t (G_ "Skipping ~a (directory already exists)... done\n") (apply throw args))))))))
target-path) (const #t) ;up
(begin (const #t) ;skip
(format #t (G_ "Creating ~a...") target-path) (const #t) ;error
(mkdir target-path) #t ;init
(display (G_ " done\n")))))) config-file-directory))
(('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 #$%initialize-gettext
(let* ((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-he-path (string-append he-path ".new"))
(new-home (getenv "GUIX_NEW_HOME")) (new-home (getenv "GUIX_NEW_HOME"))
(old-home (getenv "GUIX_OLD_HOME")) (old-home (getenv "GUIX_OLD_HOME")))
(new-files-path (string-append new-home "/files"))
;; Trailing dot is required, because files itself is symlink and
;; to make file-system-tree works it should be a directory.
(new-files-dir-path (string-append new-files-path "/."))
(new-tree ((simplify-file-tree "")
(file-system-tree new-files-dir-path))))
(when old-home (when old-home
(cleanup-symlinks old-home)) (cleanup-symlinks old-home))
(create-symlinks new-tree new-files-path) (create-symlinks new-home)
(symlink new-home new-he-path) (symlink new-home new-he-path)
(rename-file new-he-path he-path) (rename-file new-he-path he-path)