kiss: Configurable and dynamic tarball compression.

This allows you to swap between gzip and xz compression via
the new environment variable ('KISS_COMPRESS'). As of this
commit, new builds will use xz compression (making use of
all cores on the machine).

Other compression methods can easily be added by adding two
simple lines to the script. Your existing package cache will
continue to be used as the package manager will use whatever
tarball is available (for the package and version it is
looking for).

kiss

@@ -172,6 +172,15 @@ pkg_list() {
     done
 }
 
+pkg_cache() {
+    read -r version release < "$(pkg_find "$1")/version"
+
+    set +f; set -f -- "$bin_dir/$1#$version-$release.tar."*
+    tar_file=$1
+
+    [ -f "$tar_file" ]
+}
+
 pkg_sources() {
     # Download any remote package sources. The existence of local
     # files is also checked.
@@ -339,8 +348,8 @@ pkg_order() {
 
     for pkg; do
         case $pkg in
-            *.tar.gz) deps="$deps $pkg " ;;
-            *)        pkg_depends "$pkg" raw
+            *.tar.*) deps="$deps $pkg "  ;;
+            *)       pkg_depends "$pkg" raw
         esac
     done
 
@@ -493,8 +502,12 @@ pkg_tar() {
     read -r version release < "$(pkg_find "$1")/version"
 
     # Create a tar-ball from the contents of the built package.
-    "$tar" zpcf "$bin_dir/$1#$version-$release.tar.gz" -C "$pkg_dir/$1" . ||
-        die "$1" "Failed to create tar-ball"
+    "$tar" cf - -C "$pkg_dir/$1" . | 
+        case ${KISS_COMPRESS:=xz} in
+            xz) xz -zT 0 ;;
+            gz) gzip -6  ;;
+        esac \
+    > "$bin_dir/$1#$version-$release.tar.${KISS_COMPRESS:=xz}"
 
     log "$1" "Successfully created tar-ball"
 }
@@ -543,23 +556,16 @@ pkg_build() {
     # directory and are up to date.
     for pkg; do
         # Don't check for a pre-built package if it was passed
-        # to KISS directly.
-        contains "$explicit_build" "$pkg" || {
-            # Figure out the version and release.
-            read -r version release < "$(pkg_find "$pkg")/version"
+        # to KISS directly and install any pre-built binaries if 
+        # they exist.
+        ! contains "$explicit_build" "$pkg" && pkg_cache "$pkg" && {
+            log "$pkg" "Found pre-built binary, installing"
+            (KISS_FORCE=1 args i "$tar_file")
 
-            # Install any pre-built binaries if they exist.
-            # This calls 'args' to inherit a root check
-            # to 'su' to elevate permissions.
-            [ -f "$bin_dir/$pkg#$version-$release.tar.gz" ] && {
-                log "$pkg" "Found pre-built binary, installing"
-                (KISS_FORCE=1 args i "$bin_dir/$pkg#$version-$release.tar.gz")
-
-                # Remove the now installed package from the build list.
-                # See [1] at top of script.
-                # shellcheck disable=2046,2086
-                set -- $(pop "$pkg" "$@")
-            }
+            # Remove the now installed package from the build list.
+            # See [1] at top of script.
+            # shellcheck disable=2046,2086
+            set -- $(pop "$pkg" "$@")
         }
     done
 
@@ -898,18 +904,11 @@ pkg_install() {
 
     # Install can also take the full path to a tar-ball.
     # We don't need to check the repository if this is the case.
-    if [ -f "$1" ] && [ -z "${1%%*.tar.gz}" ] ; then
+    if [ -f "$1" ] && [ -z "${1%%*.tar.*}" ] ; then
         tar_file=$1
 
     else
-        # Read the version information to name the package.
-        read -r version release < "$(pkg_find "$1")/version"
-
-        # Construct the name of the package tarball.
-        tar_file=$bin_dir/$1\#$version-$release.tar.gz
-
-        [ -f "$tar_file" ] ||
-            die "Package '$1' has not been built, run 'kiss build $1'"
+        pkg_cache "$1" || die "$1" "has not been built, run 'kiss b $1'"
     fi
 
     # Figure out which package the tar-ball installs by checking for
@@ -922,10 +921,13 @@ pkg_install() {
     pkg_name=${pkg_name##*/}
 
     mkdir -p "$tar_dir/$pkg_name"
+    log "$pkg_name" "Extracting $tar_file"
 
     # Extract the tar-ball to catch any errors before installation begins.
-    "$tar" pxf "$tar_file" -C "$tar_dir/$pkg_name" ||
-        die "$pkg_name" "Failed to extract tar-ball"
+    case $tar_file in
+        *.xz) xz -dcT 0 ;;
+        *.gz) gzip -d ;;
+    esac < "$tar_file" | "$tar" pxf - -C "$tar_dir/$pkg_name"
 
     log "$pkg_name" "Checking that all dependencies are installed"