Initial commit of support for libinstall resources

The libinstall resources will be used for packaging installation
libraries, such as a basic templating engine or simple shortcut
functions and aliases.

Updated LENS array to allow for an additional 8 byte archive. Also
updated archive index. Now...
1. header
2. libinstall
3. run.sh
4. payload

Added extract_libinstall function.

Along with this, also added the new libtemplate, which provides a very
basic templating engine to be used by the end user run.sh script if
needed.

1 files changed, 51 insertions, 0 deletions

diff --git a/libinstall/template.sh b/libinstall/template.sh
new file mode 100644
index 0000000..7254d8b
--- /dev/null
+++ b/libinstall/template.sh
@@ -0,0 +1,51 @@
+#!/usr/bin/env bash
+# Pkgself builds self-extracting installers
+# Copyright (C) 2018  Aaron Ball <nullspoon@oper.io>
+#
+# 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/>.
+
+template() {
+  # Disable trace output in case it is enabled
+  #set +x
+  local _src="${1:-}"
+  local _dest="${2:-}"
+  local varname # Name of the variable, without double braces
+  local delim=$'\001'
+
+  local oldifs=${IFS}
+  export IFS=$'\n'
+
+  # Create the list of all variables referenced in the file
+  local _vars=($(grep -o -h '{{ [a-Z0-9_\-]\+ }}' ${_src} | sort | uniq))
+
+  printf "Parsing template %s -> %s\n" "${_src}" "${_dest}"
+  install -D "${_src}" "${_dest}"
+
+  for _var in ${_vars[@]}; do
+    printf "Parsing variable %s\n" "${var}"
+    _varref="$(printf ${_var} | cut -d ' ' -f 2)"
+    if [ -z "${!_varref:-}" ]; then
+      printf "Template %s variable '%s' is not set. Skipping.\n" \
+        "$(basename ${_src})" \
+        "${_varref}"
+      continue
+    fi
+
+    echo sed -i "s${delim}{{ ${_varref} }}${delim}${!_varref}${delim}g" "${_dest}"
+    sed -i "s${delim}{{ ${_varref} }}${delim}${!_varref}${delim}g" "${_dest}"
+  done
+
+  export IFS=${oldifs}
+  #set -x
+}