docker/hoodie/hadoop/prestobase/lib/mustache.sh - hudi - Git at Google


 #  Licensed to the Apache Software Foundation (ASF) under one
 #  or more contributor license agreements.  See the NOTICE file
 #  distributed with this work for additional information
 #  regarding copyright ownership.  The ASF licenses this file
 #  to you under the Apache License, Version 2.0 (the
 #  "License"); you may not use this file except in compliance
 #  with the License.  You may obtain a copy of the License at
 #
 #      http://www.apache.org/licenses/LICENSE-2.0
 #
 #  Unless required by applicable law or agreed to in writing, software
 #  distributed under the License is distributed on an "AS IS" BASIS,
 #  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 #  See the License for the specific language governing permissions and
 # limitations under the License.

 # `mustache.sh`, Mustache in POSIX shell.

 set -e

 # File descriptor 3 is commandeered for debug output, which may end up being
 # forwarded to standard error.
 [ -z "$MUSTACHE_DEBUG" ] && exec 3>/dev/null || exec 3>&2

 # File descriptor 4 is commandeered for use as a sink for literal and
 # variable output of (inverted) sections that are not destined for standard
 # output because their condition is not met.
 exec 4>/dev/null

 # File descriptor 5 is commandeered for capturing input for list processing.
 exec 5>/dev/null

 # Consume standard input one character at a time to render `mustache`(5)
 # templates with data from the environment.
 mustache() {

 	# Initialize the file descriptor to be used to emit characters.  At
 	# times this value will be 4 to send output to `/dev/null`.
 	_M_FD=1

 	# IFS must only contain '\n' so as to be able to read space and tab
 	# characters from standard input one-at-a-time.  The easiest way to
 	# convince it to actually contain the correct byte, and only the
 	# correct byte, is to use a single-quoted literal newline.
 	IFS='
 '

 	# Consuming standard input one character at a time is quite a feat
 	# within the confines of POSIX shell.  Bash's `read` builtin has
 	# `-n` for limiting the number of characters consumed.  Here it is
 	# faked using `sed`(1) to place each character on its own line.
 	# The subtlety is that real newline characters are chomped so they
 	# must be indirectly detected by checking for zero-length
 	# characters, which is done as the character is emitted.
 	_mustache_sed | _mustache
 	# TODO Replace the original value of IFS.  Be careful if it's unset.

 }

 # Process the one-character-per-line stream from `sed` via a state machine.
 # This function will be called recursively in subshell environments to
 # isolate nested section tags from the outside environment.
 _mustache() {

 	# Always start by assuming a character is a literal.
 	_M_STATE="literal"

 	# The `read` builtin consumes one line at a time but by now each line
 	# contains only a single character.
 	while read _M_C
 	do
 		echo " _M_C: $_M_C (${#_M_C}), _M_STATE: $_M_STATE" >&3
 		echo "$_M_C" >&5
 		case "$_M_STATE" in

 			# Consume a single character literal.  In the event this
 			# character and the previous character have been opening
 			# braces, progress to the "tag" state and initialize the
 			# tag name to the empty string (this invariant is relied
 			# on by the "tag" state).  If this is the first opening
 			# brace, wait and see.  Otherwise, emit this character.
 			"literal")
 				if [ -z "$_M_PREV_C" ]
 				then
 					case "$_M_C" in
 						"{") ;;
 						"") echo;;
 						*) printf "%s" "$_M_C";;
 					esac
 				else
 					case "$_M_PREV_C$_M_C" in
 						"{{") _M_STATE="tag" _M_TAG="";;
 						?"{") ;;
 						*)
 							[ "$_M_PREV_C" = "{" ] && printf "%s" "{"
 							[ -z "$_M_C" ] && echo || printf "%s" "$_M_C";;
 					esac
 				fi >&$_M_FD;;

 			# Consume the tag type and tag.
 			"tag")
 				case "$_M_PREV_C$_M_C" in

 					# A third opening brace in a row could be treated as
 					# a literal and the beginning of tag, as it is here,
 					# or as the beginning of a tag which begins with an
 					# opening brace.
 					"{{") printf "{" >&$_M_FD;;

 					# Note the type of this tag, defaulting to "variable".
 					"{#"|"{^"|"{/"|"{!"|"{>") _M_TAG_TYPE="$_M_C" _M_TAG="";;

 					# A variable tag must note the first character of the
 					# variable name.  Since it's possible that an opening
 					# brace comes in the middle of the tag, check that
 					# this is indeed the beginning of the tag.
 					"{"?)
 						if [ -z "$_M_TAG" ]
 						then
 							_M_TAG_TYPE="variable" _M_TAG="$_M_C"
 						fi;;

 					# Two closing braces in a row closes the tag.  The
 					# state resets to "literal" and the tag is processed,
 					# possibly in a subshell.
 					"}}")
 						_M_STATE="literal"
 						_mustache_tag;;

 					# A single closing brace is ignored at first.
 					?"}") ;;

 					# If the variable continues, the closing brace becomes
 					# part of the variable name.
 					"}"?) _M_TAG="$_M_TAG}";;

 					# Any other character becomes part of the variable name.
 					*) _M_TAG="$_M_TAG$_M_C";;

 				esac;;

 		esac

 		# This character becomes the previous character.
 		_M_PREV_C="$_M_C"

 	done

 }

 # Paper over different versions of cat.
 _mustache_cat() {
 	set +e
 	cat -A <"/dev/null" >"/dev/null" 2>&1
     _M_STATUS="$?"
 	set -e
 	if [ "$_M_STATUS" -eq 1 ]
     then cat -e
 	else cat -A
 	fi
 }

 # Execute a tag surrounded by backticks.  Remove the backticks first.
 _mustache_cmd() {
 	_M_CMD="$*"
 	_M_CMD="${_M_CMD#"\`"}"
 	_M_CMD="${_M_CMD%"\`"}"
 	sh -c "$_M_CMD"
 }

 # Print an error message and GTFO.  The message is the concatenation
 # of all the arguments to this function.
 _mustache_die() {
 	echo "mustache.sh: $*" >&2
 	exit 1
 }

 # Paper over differences between GNU sed and BSD sed
 _mustache_sed() {
 	_M_NEWLINE="
 "
 	set +e
 	sed -r <"/dev/null" >"/dev/null" 2>&1
     _M_STATUS="$?"
 	set -e
 	if [ "$_M_STATUS" -eq 1 ]
     then sed -E "s/./&\\$_M_NEWLINE/g; s/\\\\/\\\\\\\\/g"
 	else sed -r "s/./&\\n/g; s/\\\\/\\\\\\\\/g"
 	fi
 }

 # Process a complete tag.  Variables are emitted, sections are recursed
 # into, comments are ignored, and (for now) partials raise an error.
 _mustache_tag() {
 	case "$_M_TAG_TYPE" in

 		# Variable tags expand to the value of an environment variable
 		# or the empty string if the environment variable is unset.
 		#
 		# If the tag is surrounded by backticks, execute it as a shell
 		# command, instead, using standard output as its value.
 		#
 		# Since the variable tag has been completely consumed, return
 		# to the assumption that everything's a literal until proven
 		# otherwise for this character.
 		"variable")
 			case "$_M_TAG" in
 				"\`"*"\`") _mustache_cmd "$_M_TAG";;
 				*) eval printf "%s" "\"\$$_M_TAG\"";;
 			esac >&$_M_FD;;

 		# Section tags expand to the expanded value of the section's
 		# literals and tags if and only if the section tag is in the
 		# environment and non-empty.  Inverted section tags expand
 		# if the section tag is empty or unset in the environment.
 		#
 		# If the tag is surrounded by backticks, execute it as a shell
 		# command, instead, and process the section once for each line
 		# of standard output (made available as `_M_LINE`).
 		#
 		# Sections not being expanded are redirected to `/dev/null`.
 		"#"|"^")
 			echo " # _M_TAG: $_M_TAG" >&3
 			_M_TAG_V="$(eval printf "%s" "\"\$$_M_TAG\"")"
 			case "$_M_TAG_TYPE" in
 				"#") [ -z "$_M_TAG_V" ] && _M_FD=4;;
 				"^") [ -n "$_M_TAG_V" ] && _M_FD=4;;
 			esac
 			case "$_M_TAG" in
 				"\`"*"\`")
 					_M_CAPTURE="$(_M_SECTION_TAG="$_M_TAG" _mustache 5>&1 >&4)"
 					echo " _M_CAPTURE: $_M_CAPTURE" | _mustache_cat >&3
 					_mustache_cmd "$_M_TAG" | while read _M_LINE
 					do
 						echo " _M_LINE: $_M_LINE" >&3
 						(
 							_M_SECTION_TAG="$_M_TAG"
 							echo "$_M_CAPTURE" | _mustache
 						)
 					done;;
 				*)
 					(
 						_M_SECTION_TAG="$_M_TAG"
 						_mustache
 					);;
 			esac
 			_M_FD=1;;

 		# Closing tags for (inverted) sections must match the expected
 		# tag name.  Any redirections made when the (inverted) section
 		# opened are reset when the section closes.
 		"/")
 			echo " / _M_TAG: $_M_TAG, _M_SECTION_TAG: $_M_SECTION_TAG" >&3
 			if [ "$_M_TAG" != "$_M_SECTION_TAG" ]
 			then
 				_mustache_die "mismatched closing tag $_M_TAG," \
 					"expected $_M_SECTION_TAG"
 			fi
 			exit;;

 		# Comments do nothing.
 		"!") ;;

 		# TODO Partials.
 		">") _mustache_die "{{>$_M_TAG}} syntax not implemented";;

 	esac
 }

	# Licensed to the Apache Software Foundation (ASF) under one
	# or more contributor license agreements. See the NOTICE file
	# distributed with this work for additional information
	# regarding copyright ownership. The ASF licenses this file
	# to you under the Apache License, Version 2.0 (the
	# "License"); you may not use this file except in compliance
	# with the License. You may obtain a copy of the License at
	#
	# http://www.apache.org/licenses/LICENSE-2.0
	#
	# Unless required by applicable law or agreed to in writing, software
	# distributed under the License is distributed on an "AS IS" BASIS,
	# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	# See the License for the specific language governing permissions and
	# limitations under the License.

	# `mustache.sh`, Mustache in POSIX shell.

	set -e

	# File descriptor 3 is commandeered for debug output, which may end up being
	# forwarded to standard error.
	[ -z "$MUSTACHE_DEBUG" ] && exec 3>/dev/null \|\| exec 3>&2

	# File descriptor 4 is commandeered for use as a sink for literal and
	# variable output of (inverted) sections that are not destined for standard
	# output because their condition is not met.
	exec 4>/dev/null

	# File descriptor 5 is commandeered for capturing input for list processing.
	exec 5>/dev/null

	# Consume standard input one character at a time to render `mustache`(5)
	# templates with data from the environment.
	mustache() {

	# Initialize the file descriptor to be used to emit characters. At
	# times this value will be 4 to send output to `/dev/null`.
	_M_FD=1

	# IFS must only contain '\n' so as to be able to read space and tab
	# characters from standard input one-at-a-time. The easiest way to
	# convince it to actually contain the correct byte, and only the
	# correct byte, is to use a single-quoted literal newline.
	IFS='
	'

	# Consuming standard input one character at a time is quite a feat
	# within the confines of POSIX shell. Bash's `read` builtin has
	# `-n` for limiting the number of characters consumed. Here it is
	# faked using `sed`(1) to place each character on its own line.
	# The subtlety is that real newline characters are chomped so they
	# must be indirectly detected by checking for zero-length
	# characters, which is done as the character is emitted.
	_mustache_sed \| _mustache
	# TODO Replace the original value of IFS. Be careful if it's unset.

	}

	# Process the one-character-per-line stream from `sed` via a state machine.
	# This function will be called recursively in subshell environments to
	# isolate nested section tags from the outside environment.
	_mustache() {

	# Always start by assuming a character is a literal.
	_M_STATE="literal"

	# The `read` builtin consumes one line at a time but by now each line
	# contains only a single character.
	while read _M_C
	do
	echo " _M_C: $_M_C (${#_M_C}), _M_STATE: $_M_STATE" >&3
	echo "$_M_C" >&5
	case "$_M_STATE" in

	# Consume a single character literal. In the event this
	# character and the previous character have been opening
	# braces, progress to the "tag" state and initialize the
	# tag name to the empty string (this invariant is relied
	# on by the "tag" state). If this is the first opening
	# brace, wait and see. Otherwise, emit this character.
	"literal")
	if [ -z "$_M_PREV_C" ]
	then
	case "$_M_C" in
	"{") ;;
	"") echo;;
	*) printf "%s" "$_M_C";;
	esac
	else
	case "$_M_PREV_C$_M_C" in
	"{{") _M_STATE="tag" _M_TAG="";;
	?"{") ;;
	*)
	[ "$_M_PREV_C" = "{" ] && printf "%s" "{"
	[ -z "$_M_C" ] && echo \|\| printf "%s" "$_M_C";;
	esac
	fi >&$_M_FD;;

	# Consume the tag type and tag.
	"tag")
	case "$_M_PREV_C$_M_C" in

	# A third opening brace in a row could be treated as
	# a literal and the beginning of tag, as it is here,
	# or as the beginning of a tag which begins with an
	# opening brace.
	"{{") printf "{" >&$_M_FD;;

	# Note the type of this tag, defaulting to "variable".
	"{#"\|"{^"\|"{/"\|"{!"\|"{>") _M_TAG_TYPE="$_M_C" _M_TAG="";;

	# A variable tag must note the first character of the
	# variable name. Since it's possible that an opening
	# brace comes in the middle of the tag, check that
	# this is indeed the beginning of the tag.
	"{"?)
	if [ -z "$_M_TAG" ]
	then
	_M_TAG_TYPE="variable" _M_TAG="$_M_C"
	fi;;

	# Two closing braces in a row closes the tag. The
	# state resets to "literal" and the tag is processed,
	# possibly in a subshell.
	"}}")
	_M_STATE="literal"
	_mustache_tag;;

	# A single closing brace is ignored at first.
	?"}") ;;

	# If the variable continues, the closing brace becomes
	# part of the variable name.
	"}"?) _M_TAG="$_M_TAG}";;

	# Any other character becomes part of the variable name.
	*) _M_TAG="$_M_TAG$_M_C";;

	esac;;

	esac

	# This character becomes the previous character.
	_M_PREV_C="$_M_C"

	done

	}

	# Paper over different versions of cat.
	_mustache_cat() {
	set +e
	cat -A <"/dev/null" >"/dev/null" 2>&1
	_M_STATUS="$?"
	set -e
	if [ "$_M_STATUS" -eq 1 ]
	then cat -e
	else cat -A
	fi
	}

	# Execute a tag surrounded by backticks. Remove the backticks first.
	_mustache_cmd() {
	_M_CMD="$*"
	_M_CMD="${_M_CMD#"\`"}"
	_M_CMD="${_M_CMD%"\`"}"
	sh -c "$_M_CMD"
	}

	# Print an error message and GTFO. The message is the concatenation
	# of all the arguments to this function.
	_mustache_die() {
	echo "mustache.sh: $*" >&2
	exit 1
	}

	# Paper over differences between GNU sed and BSD sed
	_mustache_sed() {
	_M_NEWLINE="
	"
	set +e
	sed -r <"/dev/null" >"/dev/null" 2>&1
	_M_STATUS="$?"
	set -e
	if [ "$_M_STATUS" -eq 1 ]
	then sed -E "s/./&\\$_M_NEWLINE/g; s/\\\\/\\\\\\\\/g"
	else sed -r "s/./&\\n/g; s/\\\\/\\\\\\\\/g"
	fi
	}

	# Process a complete tag. Variables are emitted, sections are recursed
	# into, comments are ignored, and (for now) partials raise an error.
	_mustache_tag() {
	case "$_M_TAG_TYPE" in

	# Variable tags expand to the value of an environment variable
	# or the empty string if the environment variable is unset.
	#
	# If the tag is surrounded by backticks, execute it as a shell
	# command, instead, using standard output as its value.
	#
	# Since the variable tag has been completely consumed, return
	# to the assumption that everything's a literal until proven
	# otherwise for this character.
	"variable")
	case "$_M_TAG" in
	"\`"*"\`") _mustache_cmd "$_M_TAG";;
	*) eval printf "%s" "\"\$$_M_TAG\"";;
	esac >&$_M_FD;;

	# Section tags expand to the expanded value of the section's
	# literals and tags if and only if the section tag is in the
	# environment and non-empty. Inverted section tags expand
	# if the section tag is empty or unset in the environment.
	#
	# If the tag is surrounded by backticks, execute it as a shell
	# command, instead, and process the section once for each line
	# of standard output (made available as `_M_LINE`).
	#
	# Sections not being expanded are redirected to `/dev/null`.
	"#"\|"^")
	echo " # _M_TAG: $_M_TAG" >&3
	_M_TAG_V="$(eval printf "%s" "\"\$$_M_TAG\"")"
	case "$_M_TAG_TYPE" in
	"#") [ -z "$_M_TAG_V" ] && _M_FD=4;;
	"^") [ -n "$_M_TAG_V" ] && _M_FD=4;;
	esac
	case "$_M_TAG" in
	"\`"*"\`")
	_M_CAPTURE="$(_M_SECTION_TAG="$_M_TAG" _mustache 5>&1 >&4)"
	echo " _M_CAPTURE: $_M_CAPTURE" \| _mustache_cat >&3
	_mustache_cmd "$_M_TAG" \| while read _M_LINE
	do
	echo " _M_LINE: $_M_LINE" >&3
	(
	_M_SECTION_TAG="$_M_TAG"
	echo "$_M_CAPTURE" \| _mustache
	)
	done;;
	*)
	(
	_M_SECTION_TAG="$_M_TAG"
	_mustache
	);;
	esac
	_M_FD=1;;

	# Closing tags for (inverted) sections must match the expected
	# tag name. Any redirections made when the (inverted) section
	# opened are reset when the section closes.
	"/")
	echo " / _M_TAG: $_M_TAG, _M_SECTION_TAG: $_M_SECTION_TAG" >&3
	if [ "$_M_TAG" != "$_M_SECTION_TAG" ]
	then
	_mustache_die "mismatched closing tag $_M_TAG," \
	"expected $_M_SECTION_TAG"
	fi
	exit;;

	# Comments do nothing.
	"!") ;;

	# TODO Partials.
	">") _mustache_die "{{>$_M_TAG}} syntax not implemented";;

	esac
	}