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}";