common: added a helpers directory with common shell helpers.

common/helpers/README

@@ -0,0 +1,25 @@
+SHELL HELPERS
+=============
+
+This directory contains shell files that are read by xbps-src and can be used at any
+phase when building source packages. Only files with the `.sh' extension will be read.
+
+A shell helper must provide its own function for use in the source packages.
+The following examples illustrates a fake helper named `myhelper.sh' that provides
+the `myhelper_func' function:
+
+myhelper.sh:
+...
+myhelper_func() {
+	...
+}
+...
+
+You can then use this helper in a source package like this:
+
+srcpkgs/foo/template:
+...
+do_install() {
+	myhelper_func ...
+}
+...

common/helpers/replace-interpreter.sh

@@ -0,0 +1,41 @@
+# This helper replaces shebang paths pointing to the correct ones
+# as used by xbps. Multiple languages are supported:
+#
+#	- GNU Bash
+#	- Perl
+#	- Python
+#
+
+bash_regexp=".*sh"
+perl_regexp=".*perl[^[:space:]]*"
+python_regexp=".*python[^[:space:]]*"
+
+replace_interpreter() {
+	local lang="$1" file="$2" trsb orsb
+
+	[ -z $lang -o -z $file ] && return 1
+
+	case $lang in
+	bash)
+		orsb=$bash_regexp
+		trpath="/bin/bash"
+		;;
+	perl)
+		orsb=$perl_regexp
+		trpath="/usr/bin/perl"
+		;;
+	python)
+		orsb=$python_regexp
+		trpath="/usr/bin/python"
+		;;
+	*)
+		;;
+	esac
+
+	if [ -f $file ]; then
+		sed -i -e "1s|^#![[:space:]]*${orsb}|#!${trpath}|" $file
+		msg_normal "Transformed $lang script: ${file##$wrksrc}.\n"
+	else
+		msg_warn "Ignoring unexistent $lang script: ${file##$wrksrc}.\n"
+	fi
+}