[pacman-dev] [PATCH v2] libmakepkg: implement extendable source protocols

[Eli Schwartz]

Lookup the existence of matching functions for each protocol, and
fallback on the generic file handler. New source protocols can then be
added via thirdparty libmakepkg drop-ins without requiring modifications
to source.sh

Fixes FS#49076

Signed-off-by: Eli Schwartz <eschwartz at archlinux.org>
---

v2: In order to be truly extensible, put the get_vcs check into the
separate download_$proto functions. It's technically extensible either
way, but if this is going to be extended then our existing methods
should set a good example how to do so -- and the code is clearer.

 scripts/libmakepkg/source.sh.in     | 47 ++++++-----------------------
 scripts/libmakepkg/source/bzr.sh.in |  5 +++
 scripts/libmakepkg/source/git.sh.in |  5 +++
 scripts/libmakepkg/source/hg.sh.in  |  5 +++
 scripts/libmakepkg/source/svn.sh.in |  5 +++
 5 files changed, 30 insertions(+), 37 deletions(-)

diff --git a/scripts/libmakepkg/source.sh.in b/scripts/libmakepkg/source.sh.in
index 198efd5e..2cb7dae1 100644
--- a/scripts/libmakepkg/source.sh.in
+++ b/scripts/libmakepkg/source.sh.in
@@ -59,26 +59,11 @@ download_sources() {
 		pushd "$SRCDEST" &>/dev/null

 		local proto=$(get_protocol "$netfile")
-		case "$proto" in
-			local)
-				download_local "$netfile"
-				;;
-			bzr)
-				(( get_vcs )) && download_bzr "$netfile"
-				;;
-			git)
-				(( get_vcs )) && download_git "$netfile"
-				;;
-			hg)
-				(( get_vcs )) && download_hg "$netfile"
-				;;
-			svn)
-				(( get_vcs )) && download_svn "$netfile"
-				;;
-			*)
-				download_file "$netfile"
-				;;
-		esac
+		if declare -f download_$proto > /dev/null; then
+			download_$proto "$netfile"
+		else
+			download_file "$netfile"
+		fi

 		popd &>/dev/null
 	done
@@ -92,22 +77,10 @@ extract_sources() {
 	for netfile in "${all_sources[@]}"; do
 		local file=$(get_filename "$netfile")
 		local proto=$(get_protocol "$netfile")
-		case "$proto" in
-			bzr)
-				extract_bzr "$netfile"
-				;;
-			git)
-				extract_git "$netfile"
-				;;
-			hg)
-				extract_hg "$netfile"
-				;;
-			svn)
-				extract_svn "$netfile"
-				;;
-			*)
-				extract_file "$file"
-				;;
-		esac
+		if declare -f extract_$proto > /dev/null; then
+			extract_$proto "$netfile"
+		else
+			extract_file "$file"
+		fi
 	done
 }
diff --git a/scripts/libmakepkg/source/bzr.sh.in b/scripts/libmakepkg/source/bzr.sh.in
index 52193b58..d3f7db3b 100644
--- a/scripts/libmakepkg/source/bzr.sh.in
+++ b/scripts/libmakepkg/source/bzr.sh.in
@@ -29,6 +29,11 @@ source "$LIBRARY/util/pkgbuild.sh"


 download_bzr() {
+	# abort early if parent says not to fetch
+	if declare -p get_vcs > /dev/null 2>&1; then
+		(( get_vcs )) || return
+	fi
+
 	local netfile=$1

 	local url=$(get_url "$netfile")
diff --git a/scripts/libmakepkg/source/git.sh.in b/scripts/libmakepkg/source/git.sh.in
index 130c11e1..497a668c 100644
--- a/scripts/libmakepkg/source/git.sh.in
+++ b/scripts/libmakepkg/source/git.sh.in
@@ -29,6 +29,11 @@ source "$LIBRARY/util/pkgbuild.sh"


 download_git() {
+	# abort early if parent says not to fetch
+	if declare -p get_vcs > /dev/null 2>&1; then
+		(( get_vcs )) || return
+	fi
+
 	local netfile=$1

 	local dir=$(get_filepath "$netfile")
diff --git a/scripts/libmakepkg/source/hg.sh.in b/scripts/libmakepkg/source/hg.sh.in
index ae9aed3b..4984883e 100644
--- a/scripts/libmakepkg/source/hg.sh.in
+++ b/scripts/libmakepkg/source/hg.sh.in
@@ -29,6 +29,11 @@ source "$LIBRARY/util/pkgbuild.sh"


 download_hg() {
+	# abort early if parent says not to fetch
+	if declare -p get_vcs > /dev/null 2>&1; then
+		(( get_vcs )) || return
+	fi
+
 	local netfile=$1

 	local dir=$(get_filepath "$netfile")
diff --git a/scripts/libmakepkg/source/svn.sh.in b/scripts/libmakepkg/source/svn.sh.in
index f98779f2..48f4f24e 100644
--- a/scripts/libmakepkg/source/svn.sh.in
+++ b/scripts/libmakepkg/source/svn.sh.in
@@ -29,6 +29,11 @@ source "$LIBRARY/util/pkgbuild.sh"


 download_svn() {
+	# abort early if parent says not to fetch
+	if declare -p get_vcs > /dev/null 2>&1; then
+		(( get_vcs )) || return
+	fi
+
 	local netfile=$1

 	local fragment=${netfile#*#}
--
2.20.1