179 lines
5.2 KiB
Makefile
179 lines
5.2 KiB
Makefile
# 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)))
|
|
endef
|
|
_ge_attempt = $(if $(get-executable),$(get-executable),$(call _gea_err,$(2)))
|
|
_gea_err = $(if $(1),$(error Please set '$(1)' appropriately))
|