>From 3cc52d1aade5e9723c38c0af5fa4437cbdf1a9b6 Mon Sep 17 00:00:00 2001 From: Alex Kost Date: Mon, 6 Oct 2014 17:35:51 +0400 Subject: [PATCH] guix package: Add '--switch-generation' option. * doc/guix.texi (Invoking guix package): Update documentation. * guix/profiles.scm (shifted-generation, switch-to-generation): New procedures. * guix/scripts/package.scm: Add '--switch-generation' option. (switch-to-previous-generation): Use 'switch-to-generation'. --- doc/guix.texi | 15 +++++++++++++++ guix/profiles.scm | 36 +++++++++++++++++++++++++++++++++++- guix/scripts/package.scm | 44 +++++++++++++++++++++++++++++++++----------- 3 files changed, 83 insertions(+), 12 deletions(-) diff --git a/doc/guix.texi b/doc/guix.texi index f6357bd..c6921b1 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -784,6 +784,21 @@ Installing, removing, or upgrading packages from a generation that has been rolled back to overwrites previous future generations. Thus, the history of a profile's generations is always linear. address@hidden address@hidden address@hidden -S @var{pattern} +Switch to a particular generation defined by @var{pattern}. + address@hidden may be either a generation number or a number prefixed +with ``+'' or ``-''. The latter means: move forward/backward by a +specified number of generations. For example, if you want to return to +the latest generation after @code{--roll-back}, use address@hidden + +The difference between @code{--roll-back} and address@hidden is that @code{--switch-generation} will +not make a zeroth generation, so if a specified generation does not +exist, the current generation will not be changed. + @item --search-paths @cindex search paths Report environment variable definitions, in Bash syntax, that may be diff --git a/guix/profiles.scm b/guix/profiles.scm index 18733a6..589402e 100644 --- a/guix/profiles.scm +++ b/guix/profiles.scm @@ -71,9 +71,11 @@ generation-number generation-numbers profile-generations + shifted-generation previous-generation-number generation-time - generation-file-name)) + generation-file-name + switch-to-generation)) ;;; Commentary: ;;; @@ -569,6 +571,21 @@ former profiles were found." '() generations))) +(define* (shifted-generation profile shift + #:optional (current (generation-number profile))) + "Return PROFILE's generation shifted from the CURRENT generation by SHIFT. +SHIFT is a positive or negative number. +Return #f if there is no such generation." + (let* ((abs-shift (abs shift)) + (numbers (profile-generations profile)) + (from-current (memq current + (if (negative? shift) + (reverse numbers) + numbers)))) + (and from-current + (< abs-shift (length from-current)) + (list-ref from-current abs-shift)))) + (define (previous-generation-number profile number) "Return the number of the generation before generation NUMBER of PROFILE, or 0 if none exists. It could be NUMBER - 1, but it's not the @@ -589,4 +606,21 @@ case when generations have been deleted (there are \"holes\")." (make-time time-utc 0 (stat:ctime (stat (generation-file-name profile number))))) +(define (switch-to-generation profile number) + "Atomically switch PROFILE to the generation NUMBER." + (let ((current (generation-number profile)) + (file (generation-file-name profile number))) + (cond ((not (file-exists? profile)) + (format (current-error-port) + (_ "profile '~a' does not exist~%") + profile)) + ((not (file-exists? file)) + (format (current-error-port) + (_ "generation ~a does not exist~%") + number)) + (else + (format #t (_ "switching from generation ~a to ~a~%") + current number) + (switch-symlinks profile file))))) + ;;; profiles.scm ends here diff --git a/guix/scripts/package.scm b/guix/scripts/package.scm index fc9c37b..b071029 100644 --- a/guix/scripts/package.scm +++ b/guix/scripts/package.scm @@ -96,12 +96,9 @@ return PROFILE unchanged. The goal is to treat '-p ~/.guix-profile' as if (define (switch-to-previous-generation profile) "Atomically switch PROFILE to the previous generation." - (let* ((number (generation-number profile)) - (previous-number (previous-generation-number profile number)) - (previous-generation (generation-file-name profile previous-number))) - (format #t (_ "switching from generation ~a to ~a~%") - number previous-number) - (switch-symlinks profile previous-generation))) + (let* ((current (generation-number profile)) + (previous (previous-generation-number profile current))) + (switch-to-generation profile previous))) (define (roll-back store profile) "Roll back to the previous generation of PROFILE." @@ -409,6 +406,9 @@ Install, remove, or upgrade PACKAGES in a single transaction.\n")) -d, --delete-generations[=PATTERN] delete generations matching PATTERN")) (display (_ " + -S, --switch-generation=PATTERN + switch to a generation matching PATTERN")) + (display (_ " -p, --profile=PROFILE use PROFILE instead of the user's default profile")) (newline) (display (_ " @@ -488,6 +488,10 @@ Install, remove, or upgrade PACKAGES in a single transaction.\n")) (values (alist-cons 'delete-generations (or arg "") result) #f))) + (option '(#\S "switch-generation") #t #f + (lambda (opt name arg result arg-handler) + (values (alist-cons 'switch-generation arg result) + #f))) (option '("search-paths") #f #f (lambda (opt name arg result arg-handler) (values (cons `(query search-paths) result) @@ -713,13 +717,31 @@ more information.~%")) (generation-number profile)) ;; First roll back if asked to. - (cond ((and (assoc-ref opts 'roll-back?) (not dry-run?)) - (begin - (roll-back (%store) profile) - (process-actions (alist-delete 'roll-back? opts)))) + (cond ((and (assoc-ref opts 'roll-back?) + (not dry-run?)) + (roll-back (%store) profile) + (process-actions (alist-delete 'roll-back? opts))) + ((and (assoc-ref opts 'switch-generation) + (not dry-run?)) + (for-each + (match-lambda + (('switch-generation . pattern) + (let* ((number (string->number pattern)) + (number (and number + (case (string-ref pattern 0) + ((#\+ #\-) + (shifted-generation profile number)) + (else number))))) + (if number + (switch-to-generation profile number) + (format (current-error-port) + "Cannot switch to generation '~a'~%" pattern))) + (process-actions (alist-delete 'switch-generation opts))) + (_ #f)) + opts)) ((and (assoc-ref opts 'delete-generations) (not dry-run?)) - (filter-map + (for-each (match-lambda (('delete-generations . pattern) (cond ((not (file-exists? profile)) ; XXX: race condition -- 2.1.2