1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
|
# This allows us to work with the newline character:
define newline
endef
newline := $(newline)
# nl-escape
#
# Usage: escape = $(call nl-escape[,escape])
#
# This is used as the common way to specify
# what should replace a newline when escaping
# newlines; the default is a bizarre string.
#
nl-escape = $(if $(1),$(1),m822df3020w6a44id34bt574ctac44eb9f4n)
# escape-nl
#
# Usage: escaped-text = $(call escape-nl,text[,escape])
#
# GNU make's $(shell ...) function converts to a
# single space each newline character in the output
# produced during the expansion; this may not be
# desirable.
#
# The only solution is to change each newline into
# something that won't be converted, so that the
# information can be recovered later with
# $(call unescape-nl...)
#
escape-nl = $(subst $(newline),$(call nl-escape,$(2)),$(1))
# unescape-nl
#
# Usage: text = $(call unescape-nl,escaped-text[,escape])
#
# See escape-nl.
#
unescape-nl = $(subst $(call nl-escape,$(2)),$(newline),$(1))
# shell-escape-nl
#
# Usage: $(shell some-command | $(call shell-escape-nl[,escape]))
#
# Use this to escape newlines from within a shell call;
# the default escape is a bizarre string.
#
# NOTE: The escape is used directly as a string constant
# in an `awk' program that is delimited by shell
# single-quotes, so be wary of the characters
# that are chosen.
#
define shell-escape-nl
awk 'NR==1 {t=$$0} NR>1 {t=t "$(nl-escape)" $$0} END {printf t}'
endef
# shell-unescape-nl
#
# Usage: $(shell some-command | $(call shell-unescape-nl[,escape]))
#
# Use this to unescape newlines from within a shell call;
# the default escape is a bizarre string.
#
# NOTE: The escape is used directly as an extended regular
# expression constant in an `awk' program that is
# delimited by shell single-quotes, so be wary
# of the characters that are chosen.
#
# (The bash shell has a bug where `{gsub(...),...}' is
# misinterpreted as a brace expansion; this can be
# overcome by putting a space between `{' and `gsub').
#
define shell-unescape-nl
awk 'NR==1 {t=$$0} NR>1 {t=t "\n" $$0} END { gsub(/$(nl-escape)/,"\n",t); printf t }'
endef
# escape-for-shell-sq
#
# Usage: embeddable-text = $(call escape-for-shell-sq,text)
#
# This function produces text that is suitable for
# embedding in a shell string that is delimited by
# single-quotes.
#
escape-for-shell-sq = $(subst ','\'',$(1))
# shell-sq
#
# Usage: single-quoted-and-escaped-text = $(call shell-sq,text)
#
shell-sq = '$(escape-for-shell-sq)'
# shell-wordify
#
# Usage: wordified-text = $(call shell-wordify,text)
#
# For instance:
#
# |define text
# |hello
# |world
# |endef
# |
# |target:
# | echo $(call shell-wordify,$(text))
#
# At least GNU make gets confused by expanding a newline
# within the context of a command line of a makefile rule
# (this is in constrast to a `$(shell ...)' function call,
# which can handle it just fine).
#
# This function avoids the problem by producing a string
# that works as a shell word, regardless of whether or
# not it contains a newline.
#
# If the text to be wordified contains a newline, then
# an intrictate shell command substitution is constructed
# to render the text as a single line; when the shell
# processes the resulting escaped text, it transforms
# it into the original unescaped text.
#
# If the text does not contain a newline, then this function
# produces the same results as the `$(shell-sq)' function.
#
shell-wordify = $(if $(findstring $(newline),$(1)),$(_sw-esc-nl),$(shell-sq))
define _sw-esc-nl
"$$(echo $(call escape-nl,$(shell-sq),$(2)) | $(call shell-unescape-nl,$(2)))"
endef
# is-absolute
#
# Usage: bool-value = $(call is-absolute,path)
#
is-absolute = $(shell echo $(shell-sq) | grep ^/ -q && echo y)
# lookup
#
# Usage: absolute-executable-path-or-empty = $(call lookup,path)
#
# (It's necessary to use `sh -c' because GNU make messes up by
# trying too hard and getting things wrong).
#
lookup = $(call unescape-nl,$(shell sh -c $(_l-sh)))
_l-sh = $(call shell-sq,command -v $(shell-sq) | $(call shell-escape-nl,))
# is-executable
#
# Usage: bool-value = $(call is-executable,path)
#
# (It's necessary to use `sh -c' because GNU make messes up by
# trying too hard and getting things wrong).
#
is-executable = $(call _is-executable-helper,$(shell-sq))
_is-executable-helper = $(shell sh -c $(_is-executable-sh))
_is-executable-sh = $(call shell-sq,test -f $(1) -a -x $(1) && echo y)
# get-executable
#
# Usage: absolute-executable-path-or-empty = $(call get-executable,path)
#
# The goal is to get an absolute path for an executable;
# the `command -v' is defined by POSIX, but it's not
# necessarily very portable, so it's only used if
# relative path resolution is requested, as determined
# by the presence of a leading `/'.
#
get-executable = $(if $(1),$(if $(is-absolute),$(_ge-abspath),$(lookup)))
_ge-abspath = $(if $(is-executable),$(1))
# get-supplied-or-default-executable
#
# Usage: absolute-executable-path-or-empty = $(call get-executable-or-default,variable,default)
#
define get-executable-or-default
$(if $($(1)),$(call _ge_attempt,$($(1)),$(1)),$(call _ge_attempt,$(2),$(1)))
endef
_ge_attempt = $(if $(get-executable),$(get-executable),$(_gea_warn)$(call _gea_err,$(2)))
_gea_warn = $(warning The path '$(1)' is not executable.)
_gea_err = $(if $(1),$(error Please set '$(1)' appropriately))
# try-cc
# Usage: option = $(call try-cc, source-to-build, cc-options, msg)
ifndef V
TRY_CC_OUTPUT= > /dev/null 2>&1
endif
TRY_CC_MSG=echo " CHK $(3)" 1>&2;
try-cc = $(shell sh -c \
'TMP="$(OUTPUT)$(TMPOUT).$$$$"; \
$(TRY_CC_MSG) \
echo "$(1)" | \
$(CC) -x c - $(2) -o "$$TMP" $(TRY_CC_OUTPUT) && echo y; \
rm -f "$$TMP"')
|
