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e89431bf | 1 | ;;; GNU Guix --- Functional package management for GNU |
fcd75bdb | 2 | ;;; Copyright © 2013, 2014, 2015, 2017 Ludovic Courtès <ludo@gnu.org> |
e89431bf LC |
3 | ;;; |
4 | ;;; This file is part of GNU Guix. | |
5 | ;;; | |
6 | ;;; GNU Guix is free software; you can redistribute it and/or modify it | |
7 | ;;; under the terms of the GNU General Public License as published by | |
8 | ;;; the Free Software Foundation; either version 3 of the License, or (at | |
9 | ;;; your option) any later version. | |
10 | ;;; | |
11 | ;;; GNU Guix is distributed in the hope that it will be useful, but | |
12 | ;;; WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | ;;; GNU General Public License for more details. | |
15 | ;;; | |
16 | ;;; You should have received a copy of the GNU General Public License | |
17 | ;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>. | |
18 | ||
19 | (define-module (guix search-paths) | |
20 | #:use-module (guix records) | |
6568d2bd LC |
21 | #:use-module (guix build utils) |
22 | #:use-module (srfi srfi-1) | |
23 | #:use-module (srfi srfi-26) | |
e89431bf LC |
24 | #:use-module (ice-9 match) |
25 | #:export (<search-path-specification> | |
26 | search-path-specification | |
27 | search-path-specification? | |
28 | search-path-specification-variable | |
29 | search-path-specification-files | |
30 | search-path-specification-separator | |
31 | search-path-specification-file-type | |
32 | search-path-specification-file-pattern | |
33 | ||
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34 | $PATH |
35 | ||
e89431bf | 36 | search-path-specification->sexp |
6568d2bd | 37 | sexp->search-path-specification |
d838e702 | 38 | string-tokenize* |
b07901c0 | 39 | evaluate-search-paths |
8e3a3bc2 LC |
40 | environment-variable-definition |
41 | search-path-definition)) | |
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42 | |
43 | ;;; Commentary: | |
44 | ;;; | |
45 | ;;; This module defines "search path specifications", which allow packages to | |
46 | ;;; declare environment variables that they use to define search paths. For | |
47 | ;;; instance, GCC has the 'CPATH' variable, Guile has the 'GUILE_LOAD_PATH' | |
48 | ;;; variable, etc. | |
49 | ;;; | |
50 | ;;; Code: | |
51 | ||
52 | ;; The specification of a search path. | |
53 | (define-record-type* <search-path-specification> | |
54 | search-path-specification make-search-path-specification | |
55 | search-path-specification? | |
56 | (variable search-path-specification-variable) ;string | |
57 | (files search-path-specification-files) ;list of strings | |
fcd75bdb | 58 | (separator search-path-specification-separator ;string | #f |
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59 | (default ":")) |
60 | (file-type search-path-specification-file-type ;symbol | |
61 | (default 'directory)) | |
62 | (file-pattern search-path-specification-file-pattern ;#f | string | |
63 | (default #f))) | |
64 | ||
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65 | (define $PATH |
66 | ;; The 'PATH' variable. This variable is a bit special: it is not attached | |
67 | ;; to any package in particular. | |
68 | (search-path-specification | |
69 | (variable "PATH") | |
70 | (files '("bin" "sbin")))) | |
71 | ||
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72 | (define (search-path-specification->sexp spec) |
73 | "Return an sexp representing SPEC, a <search-path-specification>. The sexp | |
74 | corresponds to the arguments expected by `set-path-environment-variable'." | |
75 | ;; Note that this sexp format is used both by build systems and in | |
76 | ;; (guix profiles), so think twice before you change it. | |
77 | (match spec | |
78 | (($ <search-path-specification> variable files separator type pattern) | |
79 | `(,variable ,files ,separator ,type ,pattern)))) | |
80 | ||
81 | (define (sexp->search-path-specification sexp) | |
82 | "Convert SEXP, which is as returned by 'search-path-specification->sexp', to | |
83 | a <search-path-specification> object." | |
84 | (match sexp | |
85 | ((variable files separator type pattern) | |
86 | (search-path-specification | |
87 | (variable variable) | |
88 | (files files) | |
89 | (separator separator) | |
90 | (file-type type) | |
91 | (file-pattern pattern))))) | |
92 | ||
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93 | (define-syntax-rule (with-null-error-port exp) |
94 | "Evaluate EXP with the error port pointing to the bit bucket." | |
95 | (with-error-to-port (%make-void-port "w") | |
96 | (lambda () exp))) | |
97 | ||
98 | ;; XXX: This procedure used to be in (guix utils) but since we want to be able | |
99 | ;; to use (guix search-paths) on the build side, we want to avoid the | |
100 | ;; dependency on (guix utils), and so this procedure is back here for now. | |
101 | (define (string-tokenize* string separator) | |
102 | "Return the list of substrings of STRING separated by SEPARATOR. This is | |
103 | like `string-tokenize', but SEPARATOR is a string." | |
104 | (define (index string what) | |
105 | (let loop ((string string) | |
106 | (offset 0)) | |
107 | (cond ((string-null? string) | |
108 | #f) | |
109 | ((string-prefix? what string) | |
110 | offset) | |
111 | (else | |
112 | (loop (string-drop string 1) (+ 1 offset)))))) | |
113 | ||
114 | (define len | |
115 | (string-length separator)) | |
116 | ||
117 | (let loop ((string string) | |
118 | (result '())) | |
119 | (cond ((index string separator) | |
120 | => | |
121 | (lambda (offset) | |
122 | (loop (string-drop string (+ offset len)) | |
123 | (cons (substring string 0 offset) | |
124 | result)))) | |
125 | (else | |
126 | (reverse (cons string result)))))) | |
127 | ||
36914999 | 128 | (define* (evaluate-search-paths search-paths directories |
6568d2bd | 129 | #:optional (getenv (const #f))) |
36914999 LC |
130 | "Evaluate SEARCH-PATHS, a list of search-path specifications, for |
131 | DIRECTORIES, a list of directory names, and return a list of | |
132 | specification/value pairs. Use GETENV to determine the current settings and | |
133 | report only settings not already effective." | |
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134 | (define (search-path-definition spec) |
135 | (match spec | |
136 | (($ <search-path-specification> variable files #f type pattern) | |
137 | ;; Separator is #f so return the first match. | |
138 | (match (with-null-error-port | |
139 | (search-path-as-list files directories | |
140 | #:type type | |
141 | #:pattern pattern)) | |
142 | (() | |
143 | #f) | |
144 | ((head . _) | |
145 | (let ((value (getenv variable))) | |
146 | (if (and value (string=? value head)) | |
147 | #f ;VARIABLE already set appropriately | |
148 | (cons spec head)))))) | |
149 | (($ <search-path-specification> variable files separator | |
150 | type pattern) | |
6568d2bd LC |
151 | (let* ((values (or (and=> (getenv variable) |
152 | (cut string-tokenize* <> separator)) | |
153 | '())) | |
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154 | ;; XXX: Silence 'find-files' when it stumbles upon non-existent |
155 | ;; directories (see | |
156 | ;; <http://lists.gnu.org/archive/html/guix-devel/2015-01/msg00269.html>.) | |
157 | (path (with-null-error-port | |
36914999 | 158 | (search-path-as-list files directories |
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159 | #:type type |
160 | #:pattern pattern)))) | |
161 | (if (every (cut member <> values) path) | |
162 | #f ;VARIABLE is already set appropriately | |
441cfb42 | 163 | (cons spec (string-join path separator))))))) |
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164 | |
165 | (filter-map search-path-definition search-paths)) | |
166 | ||
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167 | (define* (environment-variable-definition variable value |
168 | #:key | |
169 | (kind 'exact) | |
170 | (separator ":")) | |
8e3a3bc2 | 171 | "Return a the definition of VARIABLE to VALUE in Bash syntax. |
b07901c0 LC |
172 | |
173 | KIND can be either 'exact (return the definition of VARIABLE=VALUE), | |
174 | 'prefix (return the definition where VALUE is added as a prefix to VARIABLE's | |
175 | current value), or 'suffix (return the definition where VALUE is added as a | |
176 | suffix to VARIABLE's current value.) In the case of 'prefix and 'suffix, | |
177 | SEPARATOR is used as the separator between VARIABLE's current value and its | |
178 | prefix/suffix." | |
fcd75bdb | 179 | (match (if (not separator) 'exact kind) |
b07901c0 LC |
180 | ('exact |
181 | (format #f "export ~a=\"~a\"" variable value)) | |
182 | ('prefix | |
183 | (format #f "export ~a=\"~a${~a:+~a}$~a\"" | |
184 | variable value variable separator variable)) | |
185 | ('suffix | |
186 | (format #f "export ~a=\"$~a${~a:+~a}~a\"" | |
187 | variable variable variable separator value)))) | |
188 | ||
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189 | (define* (search-path-definition search-path value |
190 | #:key (kind 'exact)) | |
191 | "Similar to 'environment-variable-definition', but applied to a | |
192 | <search-path-specification>." | |
193 | (match search-path | |
194 | (($ <search-path-specification> variable _ separator) | |
195 | (environment-variable-definition variable value | |
196 | #:kind kind | |
197 | #:separator separator)))) | |
198 | ||
e89431bf | 199 | ;;; search-paths.scm ends here |