racket/collects/repo-time-stamp/stamp.rkt
2010-12-06 07:01:36 -07:00

93 lines
3.8 KiB
Racket

#lang racket/base
(provide stamp)
#|
This file provides a single binding, `stamp', with a string value that
describes the Racket version. The format of this stamp is a date, a
SHA1, and a character describing how the information was retrieved:
"YYYY-MM-DD(SHA1/H)"
The description is attempted in several ways, with the `H' character
indicating how it was actually obtained:
* "a" -- the date and sha1 information were in the `archive-id' string
below, which means that it had that information at the time that
`git archive' created an archive out of a git repository. This is
the expected value for nightly builds.
* "g" -- `archive-id' didn't have information, but we found a git
executable and ran it.
* "d" -- an executable was not found either, but a ".git" directory
was found in the usual place, with a "HEAD" file that has eventually
lead to a SHA1. In this case, the time stamp is the stamp of the
git reference file that was used.
* "f" -- none of the above worked, so the last resort was to report
the date of this file (which can provide a rough idea how old the
tree is, but obviously this can be arbitrary). In this case the
SHA1 is missing and will be "-".
|#
(define archive-id "$Format:%ct|%h|a$")
;; when exported through `git archive', the above becomes something like
;; "1273562690|cabd414|a"
(require racket/system racket/runtime-path)
(define-runtime-path this-dir ".")
(define-runtime-path this-file "stamp.rkt")
(define stamp
(let ([rx:secs+id #rx"^([0-9]+)\\|([0-9a-f]+|-)\\|(.*?)[ \r\n]*$"])
;; info from an archive (incl. nightly builds)
(define (from-archive-id) archive-id)
;; try to run git to get the current info
(define (from-running-git)
(let ([exe (or (find-executable-path "git")
(find-executable-path "git.exe")
(and (eq? 'macosx (system-type))
(find-executable-path "/opt/local/bin/git")))])
(and exe (let ([out (open-output-string)])
(parameterize ([current-output-port out]
[current-error-port out]
[current-input-port (open-input-string "")]
[current-directory this-dir])
(system* exe "log" "-1" "--pretty=format:%ct|%h|g")
(get-output-string out))))))
;; try to find a ".git" directory (can't run git, so conventional
;; guess) and use the sha1 from that file and its date
(define (from-git-dir)
(define git-dir (build-path this-dir 'up 'up ".git"))
(let loop ([file (build-path git-dir "HEAD")])
(let ([l (and (file-exists? file)
(call-with-input-file file read-line))])
(cond [(not l) #f]
[(regexp-match #rx"^ref: +(.*)$" l)
=> (lambda (m)
(loop (build-path git-dir (cadr m))))]
[(regexp-match #px"^[[:xdigit:]]{40}$" l)
(format "~a|~a|d"
(file-or-directory-modify-seconds file)
(substring l 0 8))]))))
;; fallback: get the date of this file, no id
(define (from-this-file)
(format "~a|-|f" (file-or-directory-modify-seconds this-file)))
(for*/or ([x (list from-archive-id
from-running-git
from-git-dir
from-this-file)])
(let* ([x (x)]
[m (and (string? x) (regexp-match rx:secs+id x))]
[d (and m (seconds->date (string->number (cadr m))))]
[id (and m (caddr m))]
[how (and m (cadddr m))])
(define (pad02 f) (let ([n (f d)]) (if (< n 10) (format "0~a" n) n)))
(and d (format "~a-~a-~a(~a/~a)"
(date-year d) (pad02 date-month) (pad02 date-day)
id how))))))