gash/gash/shell-utils.scm

354 lines
12 KiB
Scheme

;;; Gash -- Guile As SHell
;;; Copyright © 2012, 2013, 2014, 2015, 2016, 2017, 2018 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2013 Andreas Enge <andreas@enge.fr>
;;; Copyright © 2013 Nikita Karetnikov <nikita@karetnikov.org>
;;; Copyright © 2015, 2018 Mark H Weaver <mhw@netris.org>
;;; Copyright © 2018 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
;;;
;;; This file is part of Gash.
;;;
;;; Gash is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; Gash is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with Gash. If not, see <http://www.gnu.org/licenses/>.
;;; Commentary:
;;; The initial guix-build-utils.scm was taken from Guix.
;;; Code:
(define-module (gash shell-utils)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-9 gnu)
#:use-module (srfi srfi-26)
#:use-module (ice-9 ftw)
#:use-module (ice-9 format)
#:use-module (ice-9 match)
#:use-module (ice-9 regex)
#:use-module (ice-9 rdelim)
#:use-module (rnrs bytevectors)
#:use-module (rnrs io ports)
#:export (
delete-file-recursively
display-tabulated
display-file
dump-port
executable-path
file-name-predicate
find-files
file-exists?*
grep*
grep+
<grep-match>
grep-match-file-name
grep-match-string
grep-match-line
grep-match-column
grep-match-end-column
mkdir-p
multi-opt
directory-exists?
executable-file?
regular-file?
symbolic-link?
))
;;; Commentary:
;;; This code is taken from (guix build utils)
;;;
;;; Directories.
;;;
(define (directory-exists? dir)
"Return #t if DIR exists and is a directory."
(let ((s (stat dir #f)))
(and s
(eq? 'directory (stat:type s)))))
(define (executable-file? file)
"Return #t if FILE exists and is executable."
(let ((s (stat file #f)))
(and s
(not (zero? (logand (stat:mode s) #o100))))))
(define (regular-file? file)
"Return #t if FILE is a regular file."
(let ((s (stat file #f)))
(and s
(eq? (stat:type s) 'regular))))
(define (symbolic-link? file)
"Return #t if FILE is a symbolic link (aka. \"symlink\".)"
(let ((s (lstat file)))
(and s
(eq? (stat:type s) 'symlink))))
(define (file-name-predicate regexp)
"Return a predicate that returns true when passed a file name whose base
name matches REGEXP."
(let ((file-rx (if (regexp? regexp)
regexp
(make-regexp regexp))))
(lambda (file stat)
(regexp-exec file-rx (basename file)))))
(define* (find-files dir #:optional (pred (const #t))
#:key (stat lstat)
directories?
fail-on-error?)
"Return the lexicographically sorted list of files under DIR for which PRED
returns true. PRED is passed two arguments: the absolute file name, and its
stat buffer; the default predicate always returns true. PRED can also be a
regular expression, in which case it is equivalent to (file-name-predicate
PRED). STAT is used to obtain file information; using 'lstat' means that
symlinks are not followed. If DIRECTORIES? is true, then directories will
also be included. If FAIL-ON-ERROR? is true, raise an exception upon error."
(let ((pred (if (procedure? pred)
pred
(file-name-predicate pred))))
;; Sort the result to get deterministic results.
(sort (file-system-fold (const #t)
(lambda (file stat result) ; leaf
(if (pred file stat)
(cons file result)
result))
(lambda (dir stat result) ; down
(if (and directories?
(pred dir stat))
(cons dir result)
result))
(lambda (dir stat result) ; up
result)
(lambda (file stat result) ; skip
result)
(lambda (file stat errno result)
(format (current-error-port) "find-files: ~a: ~a~%"
file (strerror errno))
(when fail-on-error?
(error "find-files failed"))
result)
'()
dir
stat)
string<?)))
(define* (delete-file-recursively dir
#:key follow-mounts?)
"Delete DIR recursively, like `rm -rf', without following symlinks. Don't
follow mount points either, unless FOLLOW-MOUNTS? is true. Report but ignore
errors."
(let ((dev (stat:dev (lstat dir))))
(file-system-fold (lambda (dir stat result) ; enter?
(or follow-mounts?
(= dev (stat:dev stat))))
(lambda (file stat result) ; leaf
(delete-file file))
(const #t) ; down
(lambda (dir stat result) ; up
(rmdir dir))
(const #t) ; skip
(lambda (file stat errno result)
(format (current-error-port)
"warning: failed to delete ~a: ~a~%"
file (strerror errno)))
#t
dir
;; Don't follow symlinks.
lstat)))
(define* (dump-port in out
#:key (buffer-size 16384)
(progress (lambda (t k) (k))))
"Read as much data as possible from IN and write it to OUT, using chunks of
BUFFER-SIZE bytes. Call PROGRESS at the beginning and after each successful
transfer of BUFFER-SIZE bytes or less, passing it the total number of bytes
transferred and the continuation of the transfer as a thunk."
(define buffer
(make-bytevector buffer-size))
(define (loop total bytes)
(or (eof-object? bytes)
(let ((total (+ total bytes)))
(put-bytevector out buffer 0 bytes)
(progress total
(lambda ()
(loop total
(get-bytevector-n! in buffer 0 buffer-size)))))))
;; Make sure PROGRESS is called when we start so that it can measure
;; throughput.
(progress 0
(lambda ()
(loop 0 (get-bytevector-n! in buffer 0 buffer-size)))))
(define-immutable-record-type <grep-match>
(make-grep-match file-name string line column end-column)
grep-match?
(file-name grep-match-file-name)
(string grep-match-string)
(line grep-match-line)
(column grep-match-column)
(end-column grep-match-end-column))
(define* (grep* pattern #:key (port (current-input-port)) (file-name "<stdin>"))
;; FIXME: collect later? for scripting usage implicit collect is
;; nice; for pipeline usage not so much
(let loop ((line (read-line port)) (ln 1) (matches '()))
(if (eof-object? line) (reverse matches)
(let* ((m (list-matches pattern line))
(m (and (pair? m) (car m))))
(loop (read-line port) (1+ ln)
(if m (cons (make-grep-match file-name
(match:string m)
ln
(match:start m)
(match:end m)) matches)
matches))))))
(define (grep+ pattern file)
(cond ((and (string? file)
(not (equal? file "-"))) (call-with-input-file file
(lambda (in)
(grep* pattern #:port in #:file-name file))))
(else (grep* pattern))))
(define (mkdir-p dir)
"Create directory DIR and all its ancestors."
(define absolute?
(string-prefix? "/" dir))
(define not-slash
(char-set-complement (char-set #\/)))
(let loop ((components (string-tokenize dir not-slash))
(root (if absolute?
""
".")))
(match components
((head tail ...)
(let ((path (string-append root "/" head)))
(catch 'system-error
(lambda ()
(mkdir path)
(loop tail path))
(lambda args
(if (= EEXIST (system-error-errno args))
(loop tail path)
(apply throw args))))))
(() #t))))
(define (file-exists?* file)
"Like 'file-exists?' but emits a warning if FILE is not accessible."
(catch 'system-error
(lambda ()
(stat file))
(lambda args
(let ((errno (system-error-errno args)))
(format (current-error-port) "~a: ~a~%"
file (strerror errno))
#f))))
(define* (display-tabulated lst
#:key
(terminal-width 80)
(column-gap 2))
"Display the list of string LST in as many columns as needed given
TERMINAL-WIDTH. Use COLUMN-GAP spaces between two subsequent columns."
(define len (length lst))
(define column-width
;; The width of a column. Assume all the columns have the same width
;; (GNU ls is smarter than that.)
(+ column-gap (reduce max 0 (map string-length lst))))
(define columns
(max 1
(quotient terminal-width column-width)))
(define pad
(if (zero? (modulo len columns))
0
columns))
(define items-per-column
(quotient (+ len pad) columns))
(define items (list->vector lst))
(let loop ((indexes (unfold (cut >= <> columns)
(cut * <> items-per-column)
1+
0)))
(unless (>= (first indexes) items-per-column)
(for-each (lambda (index)
(let ((item (if (< index len)
(vector-ref items index)
"")))
(display (string-pad-right item column-width))))
indexes)
(newline)
(loop (map 1+ indexes)))))
(define* (display-file file-name #:optional st)
(define (display-rwx perm sticky)
(display (if (zero? (logand perm 4)) "-" "r"))
(display (if (zero? (logand perm 2)) "-" "w"))
(display (let ((x (logand perm 1)))
(if (zero? sticky) (if (zero? x) "-" "x")
(if (= sticky 1) (if (zero? x) "T" "t")
(if (zero? x) "S" "s"))))))
(define (display-bcdfsl type)
(display
(case type
((block-special) "b")
((char-special) "c")
((directory) "d")
((fifo) "p")
((regular) "-")
((socket) "s")
((symlink) "l")
(else "?"))))
(let* ((st (or st (lstat file-name)))
(mode (stat:mode st))
(uid (stat:uid st))
(gid (stat:gid st))
(size (stat:size st))
(date (strftime "%c" (localtime (stat:mtime st))))
(sticky (ash mode -9)))
(display-bcdfsl (stat:type st))
(display-rwx (ash mode -6) (logand sticky 4))
(display-rwx (ash (logand mode #o70) -3) (logand sticky 2))
(display-rwx (logand mode #o7) (logand sticky 1))
(display " ")
(let ((ent (catch #t (compose passwd:name (cut getpwuid uid)) (const uid))))
(format #t "~8a" ent))
(display " ")
(let ((ent (catch #t (compose group:name (cut getgrgid gid)) (const gid))))
(format #t "~8a" ent))
(format #t "~8d" size)
(display " ")
(display date)
(display " "))
(display file-name))
(define (multi-opt options name)
(let ((opt? (lambda (o) (and (eq? (car o) name) (cdr o)))))
(filter-map opt? options)))
(define %not-colon (char-set-complement (char-set #\:)))
(define (executable-path)
"Return the search path for programs as a list."
(match (getenv "PATH")
(#f '())
(str (string-tokenize str %not-colon))))