gitsub.sh - third_party/libiconv - Git at Google

 #! /bin/sh
 #
 # Copyright (C) 2019 Free Software Foundation, Inc.
 # Written by Bruno Haible <bruno@clisp.org>, 2019.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation; either version 3 of the License, or
 # (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.

 # Program that manages the subdirectories of a git checkout of a package
 # that come from other packages (called "dependency packages").
 #
 # This program is similar in spirit to 'git submodule', with three
 # essential differences:
 #
 #   1) Its options are easy to remember, and do not require knowledge of
 #      'git submodule'.
 #
 #   2) The developer may choose to work on a different checkout for each
 #      dependency package.  This is important when the developer is
 #      preparing simultaneous changes to the package and the dependency
 #      package, or is using the dependency package in several packages.
 #
 #      The developer indicates this different checkout by setting the
 #      environment variable <SUBDIR>_SRCDIR (e.g. GNULIB_SRCDIR) to point to it.
 #
 #   3) The package maintainer may choose to use or not use git submodules.
 #
 #      The advantages of management through a git submodule are:
 #        - Changes to the dependency package cannot suddenly break your package.
 #          In other words, when there is an incompatible change that will cause
 #          a breakage, you can fix things at your pace; you are not forced to
 #          cope with such breakages in an emergency.
 #        - When you need to make a change as a response to a change in the
 #          dependency package, your co-developers cannot accidentally mix things
 #          up (for example, use a combination of your newest change with an
 #          older version of the dependency package).
 #
 #      The advantages of management without a git submodule (just as a plain
 #      subdirectory, let's call it a "subcheckout") are:
 #        - The simplicity: you are conceptually always using the newest revision
 #          of the dependency package.
 #        - You don't have to remember to periodially upgrade the dependency.
 #          Upgrading the dependency is an implicit operation.

 # This program is meant to be copied to the top-level directory of the package,
 # together with a configuration file.  The configuration is supposed to be
 # named '.gitmodules' and to define:
 # * The git submodules, as described in "man 5 gitmodules" or
 #   <https://git-scm.com/docs/gitmodules>.  For example:
 #
 #       [submodule "gnulib"]
 #               url = git://git.savannah.gnu.org/gnulib.git
 #               path = gnulib
 #
 #   You don't add this piece of configuration to .gitmodules manually.  Instead,
 #   you would invoke
 #     $ git submodule add --name "gnulib" -- git://git.savannah.gnu.org/gnulib.git gnulib
 #
 # * The subdirectories that are not git submodules, in a similar syntax.  For
 #   example:
 #
 #       [subcheckout "gnulib"]
 #               url = git://git.savannah.gnu.org/gnulib.git
 #               path = gnulib
 #
 # Here the URL is the one used for anonymous checkouts of the dependency
 # package. If the developer needs a checkout with write access, they can
 # either set the GNULIB_SRCDIR environment variable to point to that checkout
 # or modify the gnulib/.git/config file to enter a different URL.

 scriptname="$0"
 scriptversion='2019-04-01'
 nl='
 '
 IFS=" ""	$nl"

 # func_usage
 # outputs to stdout the --help usage message.
 func_usage ()
 {
   echo "\
 Usage: gitsub.sh pull [SUBDIR]
        gitsub.sh upgrade [SUBDIR]
        gitsub.sh checkout SUBDIR REVISION

 Operations:

 gitsub.sh pull [GIT_OPTIONS] [SUBDIR]
         You should perform this operation after 'git clone ...' and after
         every 'git pull'.
         It brings your checkout in sync with what the other developers of
         your package have committed and pushed.
         If an environment variable <SUBDIR>_SRCDIR is set, with a non-empty
         value, nothing is done for this SUBDIR.
         Supported GIT_OPTIONS (for expert git users) are:
           --reference <repository>
           --depth <depth>
           --recursive
         If no SUBDIR is specified, the operation applies to all dependencies.

 gitsub.sh upgrade [SUBDIR]
         You should perform this operation periodically, to ensure currency
         of the dependency package revisions that you use.
         This operation pulls and checks out the changes that the developers
         of the dependency package have committed and pushed.
         If an environment variable <SUBDIR>_SRCDIR is set, with a non-empty
         value, nothing is done for this SUBDIR.
         If no SUBDIR is specified, the operation applies to all dependencies.

 gitsub.sh checkout SUBDIR REVISION
         Checks out a specific revision for a dependency package.
         If an environment variable <SUBDIR>_SRCDIR is set, with a non-empty
         value, this operation fails.

 This script requires the git program in the PATH and an internet connection.
 "
 }

 # func_version
 # outputs to stdout the --version message.
 func_version ()
 {
   year=`echo "$scriptversion" | sed -e 's/^\(....\)-.*/\1/'`
   echo "\
 gitsub.sh (GNU gnulib) $scriptversion
 Copyright (C) 2019-$year Free Software Foundation, Inc.
 License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>
 This is free software: you are free to change and redistribute it.
 There is NO WARRANTY, to the extent permitted by law.
 "
   printf "Written by %s.\n" "Bruno Haible"
 }

 # func_fatal_error message
 # outputs to stderr a fatal error message, and terminates the program.
 # Input:
 # - scriptname               name of this program
 func_fatal_error ()
 {
   echo "$scriptname: *** $1" 1>&2
   echo "$scriptname: *** Stop." 1>&2
   exit 1
 }

 # func_warning message
 # Outputs to stderr a warning message,
 func_warning ()
 {
   echo "gitsub.sh: warning: $1" 1>&2
 }

 # func_note message
 # Outputs to stdout a note message,
 func_note ()
 {
   echo "gitsub.sh: note: $1"
 }

 # Unset CDPATH.  Otherwise, output from 'cd dir' can surprise callers.
 (unset CDPATH) >/dev/null 2>&1 && unset CDPATH

 # Command-line option processing.
 mode=
 while test $# -gt 0; do
   case "$1" in
     --help | --hel | --he | --h )
       func_usage
       exit $? ;;
     --version | --versio | --versi | --vers | --ver | --ve | --v )
       func_version
       exit $? ;;
     -- )
       # Stop option processing
       shift
       break ;;
     -* )
       echo "gitsub.sh: unknown option $1" 1>&2
       echo "Try 'gitsub.sh --help' for more information." 1>&2
       exit 1 ;;
     * )
       break ;;
   esac
 done
 if test $# = 0; then
   echo "gitsub.sh: missing operation argument" 1>&2
   echo "Try 'gitsub.sh --help' for more information." 1>&2
   exit 1
 fi
 case "$1" in
   pull | upgrade | checkout )
     mode="$1"
     shift ;;
   *)
     echo "gitsub.sh: unknown operation '$1'" 1>&2
     echo "Try 'gitsub.sh --help' for more information." 1>&2
     exit 1 ;;
 esac
 if { test $mode = upgrade && test $# -gt 1; } \
    || { test $mode = checkout && test $# -gt 2; }; then
   echo "gitsub.sh: too many arguments in '$mode' mode" 1>&2
   echo "Try 'gitsub.sh --help' for more information." 1>&2
   exit 1
 fi
 if test $# = 0 && test $mode = checkout; then
   echo "gitsub.sh: too few arguments in '$mode' mode" 1>&2
   echo "Try 'gitsub.sh --help' for more information." 1>&2
   exit 1
 fi

 # Read the configuration.
 # Output:
 # - subcheckout_names        space-separated list of subcheckout names
 # - submodule_names          space-separated list of submodule names
 if test -f .gitmodules; then
   subcheckout_names=`git config --file .gitmodules --get-regexp --name-only 'subcheckout\..*\.url' | sed -e 's/^subcheckout\.//' -e 's/\.url$//' | tr -d '\r' | tr '\n' ' '`
   submodule_names=`git config --file .gitmodules --get-regexp --name-only 'submodule\..*\.url' | sed -e 's/^submodule\.//' -e 's/\.url$//' | tr -d '\r' | tr '\n' ' '`
 else
   subcheckout_names=
   submodule_names=
 fi

 # func_validate SUBDIR
 # Verifies that the state on the file system is in sync with the declarations
 # in the configuration file.
 # Input:
 # - subcheckout_names        space-separated list of subcheckout names
 # - submodule_names          space-separated list of submodule names
 # Output:
 # - srcdirvar                Environment that the user can set
 # - srcdir                   Value of the environment variable
 # - path                     if $srcdir = "": relative path of the subdirectory
 # - needs_init               if $srcdir = "" and $path is not yet initialized:
 #                            true
 # - url                      if $srcdir = "" and $path is not yet initialized:
 #                            the repository URL
 func_validate ()
 {
   srcdirvar=`echo "$1" | LC_ALL=C sed -e 's/[^a-zA-Z0-9]/_/g' | LC_ALL=C tr '[a-z]' '[A-Z]'`"_SRCDIR"
   eval 'srcdir=$'"$srcdirvar"
   path=
   url=
   if test -n "$srcdir"; then
     func_note "Ignoring '$1' because $srcdirvar is set."
   else
     found=false
     needs_init=
     case " $subcheckout_names " in *" $1 "*)
       found=true
       # It ought to be a subcheckout.
       path=`git config --file .gitmodules "subcheckout.$1.path"`
       if test -z "$path"; then
         path="$1"
       fi
       if test -d "$path"; then
         if test -d "$path/.git"; then
           # It's a plain checkout.
           :
         else
           if test -f "$path/.git"; then
             # It's a submodule.
             func_fatal_error "Subdirectory '$path' is supposed to be a plain checkout, but it is a submodule."
           else
             func_warning "Ignoring '$path' because it exists but is not a git checkout."
           fi
         fi
       else
         # The subdir does not yet exist.
         needs_init=true
         url=`git config --file .gitmodules "subcheckout.$1.url"`
         if test -z "$url"; then
           func_fatal_error "Property subcheckout.$1.url is not defined in .gitmodules"
         fi
       fi
       ;;
     esac
     case " $submodule_names " in *" $1 "*)
       found=true
       # It ought to be a submodule.
       path=`git config --file .gitmodules "submodule.$1.path"`
       if test -z "$path"; then
         path="$1"
       fi
       if test -d "$path"; then
         if test -d "$path/.git" || test -f "$path/.git"; then
           # It's likely a submodule.
           :
         else
           path_if_empty=`find "$path" -prune -empty 2>/dev/null`
           if test -n "$path_if_empty"; then
             # The subdir is empty.
             needs_init=true
           else
             # The subdir is not empty.
             # It is important to report an error, because we don't want to erase
             # the user's files and 'git submodule update gnulib' sometimes reports
             # "fatal: destination path '$path' already exists and is not an empty directory."
             # but sometimes does not.
             func_fatal_error "Subdir '$path' exists but is not a git checkout."
           fi
         fi
       else
         # The subdir does not yet exist.
         needs_init=true
       fi
       # Another way to determine needs_init could be:
       # if git submodule status "$path" | grep '^-' > /dev/null; then
       #   needs_init=true
       # fi
       if test -n "$needs_init"; then
         url=`git config --file .gitmodules "submodule.$1.url"`
         if test -z "$url"; then
           func_fatal_error "Property submodule.$1.url is not defined in .gitmodules"
         fi
       fi
       ;;
     esac
     if ! $found; then
       func_fatal_error "Subdir '$1' is not configured as a subcheckout or a submodule in .gitmodules"
     fi
   fi
 }

 # func_cleanup_current_git_clone
 # Cleans up the current 'git clone' operation.
 # Input:
 # - path
 func_cleanup_current_git_clone ()
 {
   rm -rf "$path"
   func_fatal_error "git clone failed"
 }

 # func_pull SUBDIR GIT_OPTIONS
 # Implements the 'pull' operation.
 func_pull ()
 {
   func_validate "$1"
   if test -z "$srcdir"; then
     case " $subcheckout_names " in *" $1 "*)
       # It's a subcheckout.
       if test -d "$path"; then
         if test -d "$path/.git"; then
           (cd "$path" && git pull) || func_fatal_error "git operation failed"
         fi
       else
         # The subdir does not yet exist. Create a plain checkout.
         trap func_cleanup_current_git_clone 1 2 13 15
         git clone $2 "$url" "$path" || func_cleanup_current_git_clone
         trap - 1 2 13 15
       fi
       ;;
     esac
     case " $submodule_names " in *" $1 "*)
       # It's a submodule.
       if test -n "$needs_init"; then
         # Create a submodule checkout.
         git submodule init -- "$path" && git submodule update $2 -- "$path" || func_fatal_error "git operation failed"
       else
         # See https://stackoverflow.com/questions/1030169/easy-way-to-pull-latest-of-all-git-submodules
         # https://stackoverflow.com/questions/4611512/is-there-a-way-to-make-git-pull-automatically-update-submodules
         git submodule update "$path" || func_fatal_error "git operation failed"
       fi
       ;;
     esac
   fi
 }

 # func_upgrade SUBDIR
 # Implements the 'upgrade' operation.
 func_upgrade ()
 {
   func_validate "$1"
   if test -z "$srcdir"; then
     if test -d "$path"; then
       case " $subcheckout_names " in *" $1 "*)
         # It's a subcheckout.
         if test -d "$path/.git"; then
           (cd "$path" && git pull) || func_fatal_error "git operation failed"
         fi
         ;;
       esac
       case " $submodule_names " in *" $1 "*)
         # It's a submodule.
         if test -z "$needs_init"; then
           (cd "$path" && git fetch && git merge origin/master) || func_fatal_error "git operation failed"
         fi
         ;;
       esac
     else
       # The subdir does not yet exist.
       func_fatal_error "Subdirectory '$path' does not exist yet. Use 'gitsub.sh pull' to create it."
     fi
   fi
 }

 # func_checkout SUBDIR REVISION
 # Implements the 'checkout' operation.
 func_checkout ()
 {
   func_validate "$1"
   if test -z "$srcdir"; then
     if test -d "$path"; then
       case " $subcheckout_names " in *" $1 "*)
         # It's a subcheckout.
         if test -d "$path/.git"; then
           (cd "$path" && git checkout "$2") || func_fatal_error "git operation failed"
         fi
         ;;
       esac
       case " $submodule_names " in *" $1 "*)
         # It's a submodule.
         if test -z "$needs_init"; then
           (cd "$path" && git checkout "$2") || func_fatal_error "git operation failed"
         fi
         ;;
       esac
     else
       # The subdir does not yet exist.
       func_fatal_error "Subdirectory '$path' does not exist yet. Use 'gitsub.sh pull' to create it."
     fi
   fi
 }

 case "$mode" in
   pull )
     git_options=""
     while test $# -gt 0; do
       case "$1" in
         --reference=* | --depth=* | --recursive)
           git_options="$git_options $1"
           shift
           ;;
         --reference | --depth)
           git_options="$git_options $1 $2"
           shift; shift
           ;;
         *)
           break
           ;;
       esac
     done
     if test $# -gt 1; then
       echo "gitsub.sh: too many arguments in '$mode' mode" 1>&2
       echo "Try 'gitsub.sh --help' for more information." 1>&2
       exit 1
     fi
     if test $# = 0; then
       for sub in $subcheckout_names $submodule_names; do
         func_pull "$sub" "$git_options"
       done
     else
       valid=false
       for sub in $subcheckout_names $submodule_names; do
         if test "$sub" = "$1"; then
           valid=true
         fi
       done
       if $valid; then
         func_pull "$1" "$git_options"
       else
         func_fatal_error "Subdir '$1' is not configured as a subcheckout or a submodule in .gitmodules"
       fi
     fi
     ;;

   upgrade )
     if test $# = 0; then
       for sub in $subcheckout_names $submodule_names; do
         func_upgrade "$sub"
       done
     else
       valid=false
       for sub in $subcheckout_names $submodule_names; do
         if test "$sub" = "$1"; then
           valid=true
         fi
       done
       if $valid; then
         func_upgrade "$1"
       else
         func_fatal_error "Subdir '$1' is not configured as a subcheckout or a submodule in .gitmodules"
       fi
     fi
     ;;

   checkout )
     valid=false
     for sub in $subcheckout_names $submodule_names; do
       if test "$sub" = "$1"; then
         valid=true
       fi
     done
     if $valid; then
       func_checkout "$1" "$2"
     else
       func_fatal_error "Subdir '$1' is not configured as a subcheckout or a submodule in .gitmodules"
     fi
     ;;
 esac
	#! /bin/sh
	#
	# Copyright (C) 2019 Free Software Foundation, Inc.
	# Written by Bruno Haible <bruno@clisp.org>, 2019.
	#
	# This program is free software: you can redistribute it and/or modify
	# it under the terms of the GNU General Public License as published by
	# the Free Software Foundation; either version 3 of the License, or
	# (at your option) any later version.
	#
	# This program is distributed in the hope that it will be useful,
	# but WITHOUT ANY WARRANTY; without even the implied warranty of
	# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	# GNU General Public License for more details.
	#
	# You should have received a copy of the GNU General Public License
	# along with this program. If not, see <https://www.gnu.org/licenses/>.

	# Program that manages the subdirectories of a git checkout of a package
	# that come from other packages (called "dependency packages").
	#
	# This program is similar in spirit to 'git submodule', with three
	# essential differences:
	#
	# 1) Its options are easy to remember, and do not require knowledge of
	# 'git submodule'.
	#
	# 2) The developer may choose to work on a different checkout for each
	# dependency package. This is important when the developer is
	# preparing simultaneous changes to the package and the dependency
	# package, or is using the dependency package in several packages.
	#
	# The developer indicates this different checkout by setting the
	# environment variable <SUBDIR>_SRCDIR (e.g. GNULIB_SRCDIR) to point to it.
	#
	# 3) The package maintainer may choose to use or not use git submodules.
	#
	# The advantages of management through a git submodule are:
	# - Changes to the dependency package cannot suddenly break your package.
	# In other words, when there is an incompatible change that will cause
	# a breakage, you can fix things at your pace; you are not forced to
	# cope with such breakages in an emergency.
	# - When you need to make a change as a response to a change in the
	# dependency package, your co-developers cannot accidentally mix things
	# up (for example, use a combination of your newest change with an
	# older version of the dependency package).
	#
	# The advantages of management without a git submodule (just as a plain
	# subdirectory, let's call it a "subcheckout") are:
	# - The simplicity: you are conceptually always using the newest revision
	# of the dependency package.
	# - You don't have to remember to periodially upgrade the dependency.
	# Upgrading the dependency is an implicit operation.

	# This program is meant to be copied to the top-level directory of the package,
	# together with a configuration file. The configuration is supposed to be
	# named '.gitmodules' and to define:
	# * The git submodules, as described in "man 5 gitmodules" or
	# <https://git-scm.com/docs/gitmodules>. For example:
	#
	# [submodule "gnulib"]
	# url = git://git.savannah.gnu.org/gnulib.git
	# path = gnulib
	#
	# You don't add this piece of configuration to .gitmodules manually. Instead,
	# you would invoke
	# $ git submodule add --name "gnulib" -- git://git.savannah.gnu.org/gnulib.git gnulib
	#
	# * The subdirectories that are not git submodules, in a similar syntax. For
	# example:
	#
	# [subcheckout "gnulib"]
	# url = git://git.savannah.gnu.org/gnulib.git
	# path = gnulib
	#
	# Here the URL is the one used for anonymous checkouts of the dependency
	# package. If the developer needs a checkout with write access, they can
	# either set the GNULIB_SRCDIR environment variable to point to that checkout
	# or modify the gnulib/.git/config file to enter a different URL.

	scriptname="$0"
	scriptversion='2019-04-01'
	nl='
	'
	IFS=" "" $nl"

	# func_usage
	# outputs to stdout the --help usage message.
	func_usage ()
	{
	echo "\
	Usage: gitsub.sh pull [SUBDIR]
	gitsub.sh upgrade [SUBDIR]
	gitsub.sh checkout SUBDIR REVISION

	Operations:

	gitsub.sh pull [GIT_OPTIONS] [SUBDIR]
	You should perform this operation after 'git clone ...' and after
	every 'git pull'.
	It brings your checkout in sync with what the other developers of
	your package have committed and pushed.
	If an environment variable <SUBDIR>_SRCDIR is set, with a non-empty
	value, nothing is done for this SUBDIR.
	Supported GIT_OPTIONS (for expert git users) are:
	--reference <repository>
	--depth <depth>
	--recursive
	If no SUBDIR is specified, the operation applies to all dependencies.

	gitsub.sh upgrade [SUBDIR]
	You should perform this operation periodically, to ensure currency
	of the dependency package revisions that you use.
	This operation pulls and checks out the changes that the developers
	of the dependency package have committed and pushed.
	If an environment variable <SUBDIR>_SRCDIR is set, with a non-empty
	value, nothing is done for this SUBDIR.
	If no SUBDIR is specified, the operation applies to all dependencies.

	gitsub.sh checkout SUBDIR REVISION
	Checks out a specific revision for a dependency package.
	If an environment variable <SUBDIR>_SRCDIR is set, with a non-empty
	value, this operation fails.

	This script requires the git program in the PATH and an internet connection.
	"
	}

	# func_version
	# outputs to stdout the --version message.
	func_version ()
	{
	year=`echo "$scriptversion" \| sed -e 's/^\(....\)-.*/\1/'`
	echo "\
	gitsub.sh (GNU gnulib) $scriptversion
	Copyright (C) 2019-$year Free Software Foundation, Inc.
	License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>
	This is free software: you are free to change and redistribute it.
	There is NO WARRANTY, to the extent permitted by law.
	"
	printf "Written by %s.\n" "Bruno Haible"
	}

	# func_fatal_error message
	# outputs to stderr a fatal error message, and terminates the program.
	# Input:
	# - scriptname name of this program
	func_fatal_error ()
	{
	echo "$scriptname: *** $1" 1>&2
	echo "$scriptname: *** Stop." 1>&2
	exit 1
	}

	# func_warning message
	# Outputs to stderr a warning message,
	func_warning ()
	{
	echo "gitsub.sh: warning: $1" 1>&2
	}

	# func_note message
	# Outputs to stdout a note message,
	func_note ()
	{
	echo "gitsub.sh: note: $1"
	}

	# Unset CDPATH. Otherwise, output from 'cd dir' can surprise callers.
	(unset CDPATH) >/dev/null 2>&1 && unset CDPATH

	# Command-line option processing.
	mode=
	while test $# -gt 0; do
	case "$1" in
	--help \| --hel \| --he \| --h )
	func_usage
	exit $? ;;
	--version \| --versio \| --versi \| --vers \| --ver \| --ve \| --v )
	func_version
	exit $? ;;
	-- )
	# Stop option processing
	shift
	break ;;
	-* )
	echo "gitsub.sh: unknown option $1" 1>&2
	echo "Try 'gitsub.sh --help' for more information." 1>&2
	exit 1 ;;
	* )
	break ;;
	esac
	done
	if test $# = 0; then
	echo "gitsub.sh: missing operation argument" 1>&2
	echo "Try 'gitsub.sh --help' for more information." 1>&2
	exit 1
	fi
	case "$1" in
	pull \| upgrade \| checkout )
	mode="$1"
	shift ;;
	*)
	echo "gitsub.sh: unknown operation '$1'" 1>&2
	echo "Try 'gitsub.sh --help' for more information." 1>&2
	exit 1 ;;
	esac
	if { test $mode = upgrade && test $# -gt 1; } \
	\|\| { test $mode = checkout && test $# -gt 2; }; then
	echo "gitsub.sh: too many arguments in '$mode' mode" 1>&2
	echo "Try 'gitsub.sh --help' for more information." 1>&2
	exit 1
	fi
	if test $# = 0 && test $mode = checkout; then
	echo "gitsub.sh: too few arguments in '$mode' mode" 1>&2
	echo "Try 'gitsub.sh --help' for more information." 1>&2
	exit 1
	fi

	# Read the configuration.
	# Output:
	# - subcheckout_names space-separated list of subcheckout names
	# - submodule_names space-separated list of submodule names
	if test -f .gitmodules; then
	subcheckout_names=`git config --file .gitmodules --get-regexp --name-only 'subcheckout\..*\.url' \| sed -e 's/^subcheckout\.//' -e 's/\.url$//' \| tr -d '\r' \| tr '\n' ' '`
	submodule_names=`git config --file .gitmodules --get-regexp --name-only 'submodule\..*\.url' \| sed -e 's/^submodule\.//' -e 's/\.url$//' \| tr -d '\r' \| tr '\n' ' '`
	else
	subcheckout_names=
	submodule_names=
	fi

	# func_validate SUBDIR
	# Verifies that the state on the file system is in sync with the declarations
	# in the configuration file.
	# Input:
	# - subcheckout_names space-separated list of subcheckout names
	# - submodule_names space-separated list of submodule names
	# Output:
	# - srcdirvar Environment that the user can set
	# - srcdir Value of the environment variable
	# - path if $srcdir = "": relative path of the subdirectory
	# - needs_init if $srcdir = "" and $path is not yet initialized:
	# true
	# - url if $srcdir = "" and $path is not yet initialized:
	# the repository URL
	func_validate ()
	{
	srcdirvar=`echo "$1" \| LC_ALL=C sed -e 's/[^a-zA-Z0-9]/_/g' \| LC_ALL=C tr '[a-z]' '[A-Z]'`"_SRCDIR"
	eval 'srcdir=$'"$srcdirvar"
	path=
	url=
	if test -n "$srcdir"; then
	func_note "Ignoring '$1' because $srcdirvar is set."
	else
	found=false
	needs_init=
	case " $subcheckout_names " in " $1 ")
	found=true
	# It ought to be a subcheckout.
	path=`git config --file .gitmodules "subcheckout.$1.path"`
	if test -z "$path"; then
	path="$1"
	fi
	if test -d "$path"; then
	if test -d "$path/.git"; then
	# It's a plain checkout.
	:
	else
	if test -f "$path/.git"; then
	# It's a submodule.
	func_fatal_error "Subdirectory '$path' is supposed to be a plain checkout, but it is a submodule."
	else
	func_warning "Ignoring '$path' because it exists but is not a git checkout."
	fi
	fi
	else
	# The subdir does not yet exist.
	needs_init=true
	url=`git config --file .gitmodules "subcheckout.$1.url"`
	if test -z "$url"; then
	func_fatal_error "Property subcheckout.$1.url is not defined in .gitmodules"
	fi
	fi
	;;
	esac
	case " $submodule_names " in " $1 ")
	found=true
	# It ought to be a submodule.
	path=`git config --file .gitmodules "submodule.$1.path"`
	if test -z "$path"; then
	path="$1"
	fi
	if test -d "$path"; then
	if test -d "$path/.git" \|\| test -f "$path/.git"; then
	# It's likely a submodule.
	:
	else
	path_if_empty=`find "$path" -prune -empty 2>/dev/null`
	if test -n "$path_if_empty"; then
	# The subdir is empty.
	needs_init=true
	else
	# The subdir is not empty.
	# It is important to report an error, because we don't want to erase
	# the user's files and 'git submodule update gnulib' sometimes reports
	# "fatal: destination path '$path' already exists and is not an empty directory."
	# but sometimes does not.
	func_fatal_error "Subdir '$path' exists but is not a git checkout."
	fi
	fi
	else
	# The subdir does not yet exist.
	needs_init=true
	fi
	# Another way to determine needs_init could be:
	# if git submodule status "$path" \| grep '^-' > /dev/null; then
	# needs_init=true
	# fi
	if test -n "$needs_init"; then
	url=`git config --file .gitmodules "submodule.$1.url"`
	if test -z "$url"; then
	func_fatal_error "Property submodule.$1.url is not defined in .gitmodules"
	fi
	fi
	;;
	esac
	if ! $found; then
	func_fatal_error "Subdir '$1' is not configured as a subcheckout or a submodule in .gitmodules"
	fi
	fi
	}

	# func_cleanup_current_git_clone
	# Cleans up the current 'git clone' operation.
	# Input:
	# - path
	func_cleanup_current_git_clone ()
	{
	rm -rf "$path"
	func_fatal_error "git clone failed"
	}

	# func_pull SUBDIR GIT_OPTIONS
	# Implements the 'pull' operation.
	func_pull ()
	{
	func_validate "$1"
	if test -z "$srcdir"; then
	case " $subcheckout_names " in " $1 ")
	# It's a subcheckout.
	if test -d "$path"; then
	if test -d "$path/.git"; then
	(cd "$path" && git pull) \|\| func_fatal_error "git operation failed"
	fi
	else
	# The subdir does not yet exist. Create a plain checkout.
	trap func_cleanup_current_git_clone 1 2 13 15
	git clone $2 "$url" "$path" \|\| func_cleanup_current_git_clone
	trap - 1 2 13 15
	fi
	;;
	esac
	case " $submodule_names " in " $1 ")
	# It's a submodule.
	if test -n "$needs_init"; then
	# Create a submodule checkout.
	git submodule init -- "$path" && git submodule update $2 -- "$path" \|\| func_fatal_error "git operation failed"
	else
	# See https://stackoverflow.com/questions/1030169/easy-way-to-pull-latest-of-all-git-submodules
	# https://stackoverflow.com/questions/4611512/is-there-a-way-to-make-git-pull-automatically-update-submodules
	git submodule update "$path" \|\| func_fatal_error "git operation failed"
	fi
	;;
	esac
	fi
	}

	# func_upgrade SUBDIR
	# Implements the 'upgrade' operation.
	func_upgrade ()
	{
	func_validate "$1"
	if test -z "$srcdir"; then
	if test -d "$path"; then
	case " $subcheckout_names " in " $1 ")
	# It's a subcheckout.
	if test -d "$path/.git"; then
	(cd "$path" && git pull) \|\| func_fatal_error "git operation failed"
	fi
	;;
	esac
	case " $submodule_names " in " $1 ")
	# It's a submodule.
	if test -z "$needs_init"; then
	(cd "$path" && git fetch && git merge origin/master) \|\| func_fatal_error "git operation failed"
	fi
	;;
	esac
	else
	# The subdir does not yet exist.
	func_fatal_error "Subdirectory '$path' does not exist yet. Use 'gitsub.sh pull' to create it."
	fi
	fi
	}

	# func_checkout SUBDIR REVISION
	# Implements the 'checkout' operation.
	func_checkout ()
	{
	func_validate "$1"
	if test -z "$srcdir"; then
	if test -d "$path"; then
	case " $subcheckout_names " in " $1 ")
	# It's a subcheckout.
	if test -d "$path/.git"; then
	(cd "$path" && git checkout "$2") \|\| func_fatal_error "git operation failed"
	fi
	;;
	esac
	case " $submodule_names " in " $1 ")
	# It's a submodule.
	if test -z "$needs_init"; then
	(cd "$path" && git checkout "$2") \|\| func_fatal_error "git operation failed"
	fi
	;;
	esac
	else
	# The subdir does not yet exist.
	func_fatal_error "Subdirectory '$path' does not exist yet. Use 'gitsub.sh pull' to create it."
	fi
	fi
	}

	case "$mode" in
	pull )
	git_options=""
	while test $# -gt 0; do
	case "$1" in
	--reference=* \| --depth=* \| --recursive)
	git_options="$git_options $1"
	shift
	;;
	--reference \| --depth)
	git_options="$git_options $1 $2"
	shift; shift
	;;
	*)
	break
	;;
	esac
	done
	if test $# -gt 1; then
	echo "gitsub.sh: too many arguments in '$mode' mode" 1>&2
	echo "Try 'gitsub.sh --help' for more information." 1>&2
	exit 1
	fi
	if test $# = 0; then
	for sub in $subcheckout_names $submodule_names; do
	func_pull "$sub" "$git_options"
	done
	else
	valid=false
	for sub in $subcheckout_names $submodule_names; do
	if test "$sub" = "$1"; then
	valid=true
	fi
	done
	if $valid; then
	func_pull "$1" "$git_options"
	else
	func_fatal_error "Subdir '$1' is not configured as a subcheckout or a submodule in .gitmodules"
	fi
	fi
	;;

	upgrade )
	if test $# = 0; then
	for sub in $subcheckout_names $submodule_names; do
	func_upgrade "$sub"
	done
	else
	valid=false
	for sub in $subcheckout_names $submodule_names; do
	if test "$sub" = "$1"; then
	valid=true
	fi
	done
	if $valid; then
	func_upgrade "$1"
	else
	func_fatal_error "Subdir '$1' is not configured as a subcheckout or a submodule in .gitmodules"
	fi
	fi
	;;

	checkout )
	valid=false
	for sub in $subcheckout_names $submodule_names; do
	if test "$sub" = "$1"; then
	valid=true
	fi
	done
	if $valid; then
	func_checkout "$1" "$2"
	else
	func_fatal_error "Subdir '$1' is not configured as a subcheckout or a submodule in .gitmodules"
	fi
	;;
	esac