]>
Commit | Line | Data |
---|---|---|
1 | # This allows us to work with the newline character: | |
2 | define newline | |
3 | ||
4 | ||
5 | endef | |
6 | newline := $(newline) | |
7 | ||
8 | # nl-escape | |
9 | # | |
10 | # Usage: escape = $(call nl-escape[,escape]) | |
11 | # | |
12 | # This is used as the common way to specify | |
13 | # what should replace a newline when escaping | |
14 | # newlines; the default is a bizarre string. | |
15 | # | |
16 | nl-escape = $(if $(1),$(1),m822df3020w6a44id34bt574ctac44eb9f4n) | |
17 | ||
18 | # escape-nl | |
19 | # | |
20 | # Usage: escaped-text = $(call escape-nl,text[,escape]) | |
21 | # | |
22 | # GNU make's $(shell ...) function converts to a | |
23 | # single space each newline character in the output | |
24 | # produced during the expansion; this may not be | |
25 | # desirable. | |
26 | # | |
27 | # The only solution is to change each newline into | |
28 | # something that won't be converted, so that the | |
29 | # information can be recovered later with | |
30 | # $(call unescape-nl...) | |
31 | # | |
32 | escape-nl = $(subst $(newline),$(call nl-escape,$(2)),$(1)) | |
33 | ||
34 | # unescape-nl | |
35 | # | |
36 | # Usage: text = $(call unescape-nl,escaped-text[,escape]) | |
37 | # | |
38 | # See escape-nl. | |
39 | # | |
40 | unescape-nl = $(subst $(call nl-escape,$(2)),$(newline),$(1)) | |
41 | ||
42 | # shell-escape-nl | |
43 | # | |
44 | # Usage: $(shell some-command | $(call shell-escape-nl[,escape])) | |
45 | # | |
46 | # Use this to escape newlines from within a shell call; | |
47 | # the default escape is a bizarre string. | |
48 | # | |
49 | # NOTE: The escape is used directly as a string constant | |
50 | # in an `awk' program that is delimited by shell | |
51 | # single-quotes, so be wary of the characters | |
52 | # that are chosen. | |
53 | # | |
54 | define shell-escape-nl | |
55 | awk 'NR==1 {t=$$0} NR>1 {t=t "$(nl-escape)" $$0} END {printf t}' | |
56 | endef | |
57 | ||
58 | # shell-unescape-nl | |
59 | # | |
60 | # Usage: $(shell some-command | $(call shell-unescape-nl[,escape])) | |
61 | # | |
62 | # Use this to unescape newlines from within a shell call; | |
63 | # the default escape is a bizarre string. | |
64 | # | |
65 | # NOTE: The escape is used directly as an extended regular | |
66 | # expression constant in an `awk' program that is | |
67 | # delimited by shell single-quotes, so be wary | |
68 | # of the characters that are chosen. | |
69 | # | |
70 | # (The bash shell has a bug where `{gsub(...),...}' is | |
71 | # misinterpreted as a brace expansion; this can be | |
72 | # overcome by putting a space between `{' and `gsub'). | |
73 | # | |
74 | define shell-unescape-nl | |
75 | awk 'NR==1 {t=$$0} NR>1 {t=t "\n" $$0} END { gsub(/$(nl-escape)/,"\n",t); printf t }' | |
76 | endef | |
77 | ||
78 | # escape-for-shell-sq | |
79 | # | |
80 | # Usage: embeddable-text = $(call escape-for-shell-sq,text) | |
81 | # | |
82 | # This function produces text that is suitable for | |
83 | # embedding in a shell string that is delimited by | |
84 | # single-quotes. | |
85 | # | |
86 | escape-for-shell-sq = $(subst ','\'',$(1)) | |
87 | ||
88 | # shell-sq | |
89 | # | |
90 | # Usage: single-quoted-and-escaped-text = $(call shell-sq,text) | |
91 | # | |
92 | shell-sq = '$(escape-for-shell-sq)' | |
93 | ||
94 | # shell-wordify | |
95 | # | |
96 | # Usage: wordified-text = $(call shell-wordify,text) | |
97 | # | |
98 | # For instance: | |
99 | # | |
100 | # |define text | |
101 | # |hello | |
102 | # |world | |
103 | # |endef | |
104 | # | | |
105 | # |target: | |
106 | # | echo $(call shell-wordify,$(text)) | |
107 | # | |
108 | # At least GNU make gets confused by expanding a newline | |
109 | # within the context of a command line of a makefile rule | |
110 | # (this is in constrast to a `$(shell ...)' function call, | |
111 | # which can handle it just fine). | |
112 | # | |
113 | # This function avoids the problem by producing a string | |
114 | # that works as a shell word, regardless of whether or | |
115 | # not it contains a newline. | |
116 | # | |
117 | # If the text to be wordified contains a newline, then | |
118 | # an intrictate shell command substitution is constructed | |
119 | # to render the text as a single line; when the shell | |
120 | # processes the resulting escaped text, it transforms | |
121 | # it into the original unescaped text. | |
122 | # | |
123 | # If the text does not contain a newline, then this function | |
124 | # produces the same results as the `$(shell-sq)' function. | |
125 | # | |
126 | shell-wordify = $(if $(findstring $(newline),$(1)),$(_sw-esc-nl),$(shell-sq)) | |
127 | define _sw-esc-nl | |
128 | "$$(echo $(call escape-nl,$(shell-sq),$(2)) | $(call shell-unescape-nl,$(2)))" | |
129 | endef | |
130 | ||
131 | # is-absolute | |
132 | # | |
133 | # Usage: bool-value = $(call is-absolute,path) | |
134 | # | |
135 | is-absolute = $(shell echo $(shell-sq) | grep -q ^/ && echo y) | |
136 | ||
137 | # lookup | |
138 | # | |
139 | # Usage: absolute-executable-path-or-empty = $(call lookup,path) | |
140 | # | |
141 | # (It's necessary to use `sh -c' because GNU make messes up by | |
142 | # trying too hard and getting things wrong). | |
143 | # | |
144 | lookup = $(call unescape-nl,$(shell sh -c $(_l-sh))) | |
145 | _l-sh = $(call shell-sq,command -v $(shell-sq) | $(call shell-escape-nl,)) | |
146 | ||
147 | # is-executable | |
148 | # | |
149 | # Usage: bool-value = $(call is-executable,path) | |
150 | # | |
151 | # (It's necessary to use `sh -c' because GNU make messes up by | |
152 | # trying too hard and getting things wrong). | |
153 | # | |
154 | is-executable = $(call _is-executable-helper,$(shell-sq)) | |
155 | _is-executable-helper = $(shell sh -c $(_is-executable-sh)) | |
156 | _is-executable-sh = $(call shell-sq,test -f $(1) -a -x $(1) && echo y) | |
157 | ||
158 | # get-executable | |
159 | # | |
160 | # Usage: absolute-executable-path-or-empty = $(call get-executable,path) | |
161 | # | |
162 | # The goal is to get an absolute path for an executable; | |
163 | # the `command -v' is defined by POSIX, but it's not | |
164 | # necessarily very portable, so it's only used if | |
165 | # relative path resolution is requested, as determined | |
166 | # by the presence of a leading `/'. | |
167 | # | |
168 | get-executable = $(if $(1),$(if $(is-absolute),$(_ge-abspath),$(lookup))) | |
169 | _ge-abspath = $(if $(is-executable),$(1)) | |
170 | ||
171 | # get-supplied-or-default-executable | |
172 | # | |
173 | # Usage: absolute-executable-path-or-empty = $(call get-executable-or-default,variable,default) | |
174 | # | |
175 | define get-executable-or-default | |
176 | $(if $($(1)),$(call _ge_attempt,$($(1)),$(1)),$(call _ge_attempt,$(2))) | |
177 | endef | |
178 | _ge_attempt = $(if $(get-executable),$(get-executable),$(call _gea_err,$(2))) | |
179 | _gea_err = $(if $(1),$(error Please set '$(1)' appropriately)) |