scripts/*: add Makefile generator.zv/genmake

This commit adds a few scripts to the packages repository:

  * configure

        Typical 'configure' script; run to see usage.

  * scripts/genmake

        Generates a top-level 'Makefile' that will either
        build packages in the correct order, or sleep to
        simulate package builds. The main purpose of this
        tool is to enable concurrent package builds, and
        to provide a framework to analyze build strategies.

When a dependency is updated, it is the responsibility of
the maintainer to relbump all dependent packages. This tool
is intended to facilitate concurrent package builds, not be
a comprehensive maintenance tool.

1 files changed, 93 insertions, 0 deletions

diff --git a/scripts/genmake b/scripts/genmake
new file mode 100755
index 000000000..79a89175a
--- /dev/null
+++ b/scripts/genmake
@@ -0,0 +1,93 @@
+#!/bin/sh -e
+
+# ./scripts/deplist system | ./scripts/genmake [0|1]
+
+##
+# This script reads from stdin and generates
+# a Makefile in the repository's root.
+#
+# The first argument to this script is a value {0,1}
+# indicating whether to generate real rules or fake
+# (simulation) rules. Fake rules might be 'sleep 1'
+# or can be user-defined.
+#
+# NOTE: out-of-tree builds are not supported.
+#
+
+HERE="$(dirname $(readlink -f ${0}))";
+DEST="${HERE}"/../Makefile;
+TEMP="$(mktemp)";
+
+##
+# Build recipes.
+#
+# FIXME: is $(@D) POSIX or $(%/built=%) required?
+#
+rule_real=$(cat <<"EOF"
+	@cd $(@D) && abuild -r
+EOF
+);
+rule_fake=$(cat <<"EOF"
+	@echo $(@D)
+	@sleep 1
+EOF
+);
+
+##
+# Read deplist from stdin, synthesize Makefile targets.
+#
+awk '{ $(NF+1)=$1; print $0 }' `# duplicate first column to last` \
+    | sed > "${TEMP}" -E `# use extended regex, write to temp file ` \
+    -e 's/ /: /' `# append colon to first column` \
+    -e '/: /s@( |$)@/built @2g' `# append '/built' to all dependencies` \
+    -e 's/ $//g' `# trim trailing spaces` \
+    ;
+
+##
+# Internal; convenience only.
+#
+list=$(grep : "${TEMP}" \
+    | cut -d: -f1 \
+    | xargs \
+);
+
+##
+# Create (or truncate) the output Makefile.
+#
+# Default target builds everything.
+#
+printf "all: %s\n" "${list}" > "${DEST}";
+
+##
+# Append generic target build recipe.
+#
+rule=;
+case ${1} in
+    0) rule="${rule_real}"; ;;
+    1) rule="${rule_fake}"; ;;
+    *) printf "E: Invalid mode '%s'\n" "${1}"; exit 1; ;;
+esac
+cat >> "${DEST}" <<EOF
+%/built: %/APKBUILD
+${rule}
+	@touch \$@
+clean:
+	@find \$(CURDIR) -type f -name built -print -delete
+distclean:
+	@rm -fv \
+		\$(CURDIR)/Makefile \
+		\$(CURDIR)/scripts/.index \
+		\$(CURDIR)/scripts/sgrep \
+		\$(CURDIR)/scripts/tsort \
+		;
+EOF
+
+##
+# Append target rules to output Makefile.
+#
+cat >> "${DEST}" "${TEMP}";
+
+##
+# Clean up.
+#
+rm "${TEMP}";