libmakepkg: implement extendable source protocols

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: Allan McRae <allan@archlinux.org>

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#*#}