From 3bf2e72cdfa79a465e94ef3102eeb0120407fe79 Mon Sep 17 00:00:00 2001
From: Zach van Rijn <me@zv.io>
Date: Sat, 4 Feb 2023 01:03:24 -0600
Subject: scripts/*: add Makefile generator.

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.
---
 .gitignore      |   2 ++
 configure       | 103 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 scripts/genmake |  93 ++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 198 insertions(+)
 create mode 100755 configure
 create mode 100755 scripts/genmake

diff --git a/.gitignore b/.gitignore
index 5c5ff1687..4d70126d3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,5 @@ pkg
 scripts/sgrep
 scripts/tsort
 scripts/.index
+Makefile
+built
diff --git a/configure b/configure
new file mode 100755
index 000000000..72abed07d
--- /dev/null
+++ b/configure
@@ -0,0 +1,103 @@
+#!/bin/sh -e
+
+HERE="$(dirname $(readlink -f ${0}))";
+
+##
+# Full list of all possible repositories.
+#
+repos=$(grep -v ^# <<EOF
+system
+user
+legacy
+experimental
+EOF
+);
+
+##
+# Do not build any repos by default.
+#
+build="";
+
+##
+# Usage.
+#
+usage ()
+{
+    printf "Usage: %s OPTION [OPTION] ...\n" "${0}";
+
+    printf "\nOptions:\n\n";
+    cat <<"EOF"
+    --simulate      Sleep 1 second instead of build
+EOF
+
+    printf "\nRepositories:\n\n";
+    for k in ${repos}; do
+        printf "    --enable-%s\n" "${k}";
+    done
+    printf "\n";
+}
+
+##
+# Enable repositories only explicitly.
+#
+_find=;
+_fake=0; # default not a simulation
+for arg; do
+    case "${arg}" in
+        --enable-*)
+            for repo in ${repos}; do
+                _find=0;
+                if test "${arg##*-}" = "${repo}"; then
+                    build="${build} ${repo}";
+                    _find=1;
+                    break;
+                fi
+            done
+            if test ${_find} -eq 0; then
+                printf "E: Repository '%s' is not supported!\n" "${arg##*-}";
+                exit 1;
+            fi
+            ;;
+        --simulate)
+            _fake=1;
+            ;;
+        *)
+            printf "E: Option '%s' is not supported!\n" "${arg}";
+            exit 1;
+            ;;
+    esac
+done
+
+##
+# Sorted order.
+#
+build=$(printf "%s\n" "${build}" | tr ' ' '\n' | sort | uniq | xargs);
+
+##
+# Sanity checks.
+#
+if test "${#build}" -eq 0; then
+    usage;
+    exit 0;
+fi
+
+##
+# Generate Makefile.
+#
+printf "Generating subpackage index ...\n";
+"${HERE}"/scripts/setup;
+printf "Generating dependency list ...\n";
+"${HERE}"/scripts/deplist ${build} | "${HERE}"/scripts/genmake ${_fake};
+
+##
+# Generate report.
+#
+printf "\nSuccess!\n\n";
+
+_numpkgs=$(grep -E '^.*/.*:' "${HERE}"/Makefile | wc -l);
+printf "    Packages\t: %s\n" "${_numpkgs}";
+printf "\n";
+
+if test ${_fake} -eq 1; then
+    printf "SIMULATION ONLY! NO PACKAGES WILL BE BUILT!\n\n";
+fi
diff --git a/scripts/genmake b/scripts/genmake
new file mode 100755
index 000000000..79a89175a
--- /dev/null
+++ b/scripts/genmake
@@ -0,0 +1,93 @@
+#!/bin/sh -e
+
+# ./scripts/deplist system | ./scripts/genmake [0|1]
+
+##
+# This script reads from stdin and generates
+# a Makefile in the repository's root.
+#
+# The first argument to this script is a value {0,1}
+# indicating whether to generate real rules or fake
+# (simulation) rules. Fake rules might be 'sleep 1'
+# or can be user-defined.
+#
+# NOTE: out-of-tree builds are not supported.
+#
+
+HERE="$(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}";
-- 
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