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Diffstat (limited to 'tools/scripts/utilities.mak')
| -rw-r--r-- | tools/scripts/utilities.mak | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/tools/scripts/utilities.mak b/tools/scripts/utilities.mak new file mode 100644 index 000000000..c16ce8330 --- /dev/null +++ b/tools/scripts/utilities.mak @@ -0,0 +1,179 @@ +# 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)) |