# Copyright 1999-2007 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2
# $Header: /var/cvsroot/gentoo-x86/eclass/elisp-common.eclass,v 1.28 2007/09/22 20:25:30 ulm Exp $
#
# Copyright 2007 Christian Faulhammer <opfer@gentoo.org>
# Copyright 2002-2004 Matthew Kennedy <mkennedy@gentoo.org>
# Copyright 2004-2005 Mamoru Komachi <usata@gentoo.org>
# Copyright 2003 Jeremy Maitin-Shepard <jbms@attbi.com>
# Copyright 2007 Ulrich Mueller <ulm@gentoo.org>
#
# @ECLASS: elisp-common.eclass
# @MAINTAINER:
# Feel free to contact the Emacs team through emacs@gentoo.org if you have
# problems, suggestions or questions.
# @BLURB: Emacs-related installation utilities
# @DESCRIPTION:
#
# Usually you want to use this eclass for (optional) GNU Emacs support of
# your package.  This is NOT for XEmacs!
#
# Many of the steps here are sometimes done by the build system of your
# package (especially compilation), so this is mainly for standalone elisp
# files you gathered from somewhere else.
#
# When relying on the emacs USE flag, you need to add
#
#   	emacs? ( virtual/emacs )
#
# to your DEPEND/RDEPEND line and use the functions provided here to bring
# the files to the correct locations.
#
# .SS
# src_compile() usage:
#
# An elisp file is compiled by the elisp-compile() function defined here and
# simply takes the source files as arguments.
#
#   	elisp-compile *.el || die "elisp-compile failed"
#
# In the case of interdependent elisp files, you can use the elisp-comp()
# function which makes sure all files are loadable.
#
#   	elisp-comp *.el || die "elisp-comp failed"
#
# Function elisp-make-autoload-file() can be used to generate a file with
# autoload definitions for the lisp functions.  It takes the output file name
# (default: "${PN}-autoloads.el") and a list of directories (default: working
# directory) as its arguments.  Use of this function requires that the elisp
# source files contain magic ";;;###autoload" comments. See the Emacs Lisp
# Reference Manual (node "Autoload") for a detailed explanation.
#
# .SS
# src_install() usage:
#
# The resulting compiled files (.elc) should be put in a subdirectory of
# /usr/share/emacs/site-lisp/ which is named after the first argument
# of elisp-install().  The following parameters are the files to be put in
# that directory.  Usually the subdirectory should be ${PN}, you can choose
# something else, but remember to tell elisp-site-file-install() (see below)
# the change, as it defaults to ${PN}.
#
#   	elisp-install ${PN} *.el *.elc || die "elisp-install failed"
#
# To let the Emacs support be activated by Emacs on startup, you need
# to provide a site file (shipped in ${FILESDIR}) which contains the startup
# code (have a look in the documentation of your software).  Normally this
# would look like this:
#
#   	;;; csv-mode site-lisp configuration
#
#   	(add-to-list 'load-path "@SITELISP@")
#   	(add-to-list 'auto-mode-alist '("\\.csv\\'" . csv-mode))
#   	(autoload 'csv-mode "csv-mode" "Major mode for csv files." t)
#
# If your Emacs support files are installed in a subdirectory of
# /usr/share/emacs/site-lisp/ (which is recommended if more than one file is
# installed), you need to extend Emacs' load-path as shown in the first
# non-comment.  The elisp-site-file-install() function of this eclass will
# replace "@SITELISP@" by the actual path.
#
# The next line tells Emacs to load the mode opening a file ending with
# ".csv" and load functions depending on the context and needed features.
# Be careful though.  Commands as "load-library" or "require" bloat the
# editor as they are loaded on every startup.  When having a lot of Emacs
# support files, users may be annoyed by the start-up time.  Also avoid
# keybindings as they might interfere with the user's settings.  Give a hint
# in pkg_postinst(), which should be enough.
#
# The naming scheme for this site file is "[0-9][0-9]*-gentoo.el", where the
# two digits at the beginning define the loading order.  So if you depend on
# another Emacs package, your site file's number must be higher!
#
# Best practice is to define a SITEFILE variable in the global scope of your
# ebuild (right after DEPEND e.g.):
#
#   	SITEFILE=50${PN}-gentoo.el
#
# Which is then installed by
#
#   	elisp-site-file-install "${FILESDIR}/${SITEFILE}"
#
# in src_install().  If your subdirectory is not named ${PN}, give the
# differing name as second argument.
#
# .SS
# pkg_postinst() / pkg_postrm() usage:
#
# After that you need to recreate the start-up file of Emacs after emerging
# and unmerging by using
#
#   	pkg_postinst() {
#   		elisp-site-regen
#   	}
#
#   	pkg_postrm() {
#   		elisp-site-regen
#   	}
#
# When having optional Emacs support, you should prepend "use emacs &&" to
# above calls of elisp-site-regen().  Don't use "has_version virtual/emacs"!
# When unmerging the state of the emacs USE flag is taken from the package
# database and not from the environment, so it is no problem when you unset
# USE=emacs between merge and unmerge of a package.
#
# .SS
# Miscellaneous functions:
#
# elisp-emacs-version() outputs the version of the currently active Emacs.

SITELISP=/usr/share/emacs/site-lisp
SITEFILE=50${PN}-gentoo.el
EMACS=/usr/bin/emacs
# The following works for Emacs versions 18-23, don't change it.
EMACS_BATCH_CLEAN="${EMACS} -batch -q --no-site-file"

# @FUNCTION: elisp-compile
# @USAGE: <list of elisp files>
# @DESCRIPTION:
# Byte-compile Emacs Lisp files.

elisp-compile() {
	einfo "Compiling GNU Emacs Elisp files ..."
	${EMACS_BATCH_CLEAN} -f batch-byte-compile "$@"
}

# @FUNCTION: elisp-emacs-version
# @DESCRIPTION:
# Output version of currently active Emacs.

elisp-emacs-version() {
	# The following will work for at least versions 18-23.
	echo "(princ emacs-version)" >"${T}"/emacs-version.el
	${EMACS_BATCH_CLEAN} -l "${T}"/emacs-version.el
}

# @FUNCTION: elisp-make-autoload-file
# @USAGE: [output file] [list of directories]
# @DESCRIPTION:
# Generate a file with autoload definitions for the lisp functions.

elisp-make-autoload-file () {
	local f="${1:-${PN}-autoloads.el}"
	shift
	einfo "Generating autoload file for GNU Emacs ..."

	sed 's/^FF/\f/' >"${f}" <<-EOF
	;;; ${f##*/} --- autoloads for ${P}

	;;; Commentary:
	;; Automatically generated by elisp-common.eclass
	;; DO NOT EDIT THIS FILE

	;;; Code:
	FF
	;; Local Variables:
	;; version-control: never
	;; no-byte-compile: t
	;; no-update-autoloads: t
	;; End:
	;;; ${f##*/} ends here
	EOF

	${EMACS_BATCH_CLEAN} \
		--eval "(setq make-backup-files nil)" \
		--eval "(setq generated-autoload-file (expand-file-name \"${f}\"))" \
		-f batch-update-autoloads "${@-.}"
}

# @FUNCTION: elisp-install
# @USAGE: <subdirectory> <list of files>
# @DESCRIPTION:
# Install files in SITELISP directory.

elisp-install() {
	local subdir="$1"
	shift
	einfo "Installing Elisp files for GNU Emacs support ..."
	( # subshell to avoid pollution of calling environment
		insinto "${SITELISP}/${subdir}"
		doins "$@"
	)
}

# @FUNCTION: elisp-site-file-install
# @USAGE: <site-init file> [subdirectory]
# @DESCRIPTION:
# Install Emacs site-init file in SITELISP directory.

elisp-site-file-install() {
	local sf="$1" my_pn="${2:-${PN}}"
	einfo "Installing site initialisation file for GNU Emacs ..."
	cp "${sf}" "${T}"
	sed -i "s:@SITELISP@:${SITELISP}/${my_pn}:g" "${T}/$(basename "${sf}")"
	( # subshell to avoid pollution of calling environment
		insinto "${SITELISP}"
		doins "${T}/$(basename "${sf}")"
	)
}

# @FUNCTION: elisp-site-regen
# @DESCRIPTION:
# Regenerate site-gentoo.el file.

elisp-site-regen() {
	local sflist sf line

	einfon "Regenerating ${SITELISP}/site-gentoo.el ..."
	cat <<-EOF >"${T}"/site-gentoo.el
	;;; site-gentoo.el --- site initialisation for Gentoo-installed packages

	;;; Commentary:
	;; Automatically generated by elisp-common.eclass
	;; DO NOT EDIT THIS FILE

	;;; Code:
	EOF

	for sf in "${ROOT}${SITELISP}"/[0-9][0-9]*-gentoo.el
	do
		[ -r "${sf}" ] || continue
		sflist="${sflist} $(basename "${sf}")"
		cat "${sf}" >>"${T}"/site-gentoo.el
	done

	cat <<-EOF >>"${T}"/site-gentoo.el

	(provide 'site-gentoo)

	;; Local Variables:
	;; no-byte-compile: t
	;; End:
	;;; site-gentoo.el ends here
	EOF

	if cmp -s "${ROOT}${SITELISP}"/site-gentoo.el "${T}"/site-gentoo.el; then
		# This prevents outputting unnecessary text when there
		# was actually no change
		# A case is a remerge where we have doubled output
		echo " no changes."
	else
		mv "${T}"/site-gentoo.el "${ROOT}${SITELISP}"/site-gentoo.el
		echo; einfo
		for sf in ${sflist}; do
			einfo "  Adding ${sf} ..."
		done
		while read line; do einfo "${line}"; done <<EOF

All site initialisation for Gentoo-installed packages is added to
/usr/share/emacs/site-lisp/site-gentoo.el; site-start.el is no longer
managed by Gentoo. You are responsible for all maintenance of
site-start.el if there is such a file.

In order for this site initialisation to be loaded for all users
automatically, you can add a line like this:

	(load "/usr/share/emacs/site-lisp/site-gentoo" nil t)

to /usr/share/emacs/site-lisp/site-start.el.  Alternatively, that line
can be added by individual users to their initialisation files, or for
greater flexibility, users can select which of the package-specific
initialisation files in /usr/share/emacs/site-lisp/ to load.
EOF
		echo
	fi
}

# @FUNCTION: elisp-comp
# @USAGE: <list of elisp files>
# @DESCRIPTION:
# Byte-compile interdependent Emacs Lisp files.
#
# This function byte-compiles all ".el" files which are part of its
# arguments, using GNU Emacs, and puts the resulting ".elc" files into the
# current directory, so disregarding the original directories used in ".el"
# arguments.
#
# This function manages in such a way that all Emacs Lisp files to be
# compiled are made visible between themselves, in the event they require or
# load one another.

elisp-comp() {
	# Copyright 1995 Free Software Foundation, Inc.
	# François Pinard <pinard@iro.umontreal.ca>, 1995.
	# Originally taken from GNU autotools.

	test $# -gt 0 || return 1

	if test -z "${EMACS}" || test "${EMACS}" = "t"; then
		# Value of "t" means we are running in a shell under Emacs.
		# Just assume Emacs is called "emacs".
		EMACS=/usr/bin/emacs
	fi
	einfo "Compiling GNU Emacs Elisp files ..."

	tempdir=elc.$$
	mkdir ${tempdir}
	cp "$@" ${tempdir}
	pushd ${tempdir}

	echo "(add-to-list 'load-path \"../\")" > script
	${EMACS_BATCH_CLEAN} -l script -f batch-byte-compile *.el
	local ret=$?
	mv *.elc ..

	popd
	rm -fr ${tempdir}
	return ${ret}
}