1 files changed, 225 insertions, 0 deletions
diff --git a/tools/cdeps.sh b/tools/cdeps.sh
new file mode 100755
index 0000000..dd48d74
--- /dev/null
+++ b/tools/cdeps.sh
@@ -0,0 +1,225 @@
+#!/bin/sh
+set -eu
+
+. tools/lib.sh
+
+usage() {
+	cat <<-'EOF'
+		Usage:
+		  tools/cdeps.sh FILE...
+		  tools/cdeps.sh -h
+	EOF
+}
+
+help() {
+	cat <<-'EOF'
+
+
+		Options:
+		  -h, --help    show this message
+
+		  FILE          toplevel entrypoint file
+
+
+		Given a list of C FILEs, generate the Makefile dependencies
+		between them.
+
+		We have 3 types of object files:
+		- .o: plain object files;
+		- .lo: object files compiled as relocatable so it can be
+		  included in a shared library;
+		- .to: compiled with -DTEST so it can expose its embedded unit
+		  tests;
+
+		We also have 2 aggregate files:
+		- .ta: an ar(1)-chive that includes all the .o dependencies the
+		  $NAME.ta, plus the $NAME.to object.  The goal is to have
+		  "dep1.o", "dep2.o", ... "depN.o" included in the archive,
+		  alongside "$NAME.to", so that recompiling "depN.o" would
+		  replace only this file in the archive;
+		- .t: an executable "$NAME.t" derived from just linking together
+		  all the objects inside a ".ta".  Since the "main()" function
+		  was only exposed in the "$NAME.to" via the -DTEST flag, this
+		  executable is the runnable instance of all unit tests present
+		  in "$NAME.c".  Its exit code determines if its test suite
+		  execution is successful.
+
+		Also in order to run the unit tests without having to relink
+		them on each run, we have:
+		- .t-run: a dedicated virtual target that does nothing but
+		  execute the tests.  In order to assert the binaries exist,
+		  each "$NAME.t-run" virtual target depends on the equivalent
+		  "$NAME".t physical target.
+
+		There are 2 types of dependencies that are generated:
+		1. self dependencies;
+		2. inter dependencies.
+
+		The self dependencies are the ones across different
+		manifestations of the same file so all derived assets are
+		correctly kept up-to-date:
+		- $NAME.o $NAME.lo $NAME.to: $NAME.h
+
+		  As the .SUFFIXES rule already covers the dependency to the
+		  orinal $NAME.c file, all we do is say that whenever the public
+		  interface of these binaries change, they need to be
+		  recompiled;
+		- $NAME.ta: $NAME.to
+
+		  We make sure to include in each test archive (ta) file its own
+		  binary with unit tests.  We include the "depN.o" dependencies
+		  later;
+		- $NAME.t-run: $NAME.t
+
+		  Enforce that the binary exists before we run them.
+
+		After we establish the self dependencies, we scrub each file's
+		content looking for `#include "..."` lines that denote
+		dependency to other C file.  Once we do that we'll have:
+		- $NAME.o $NAME.lo $NAME.to: dep1.h dep2.h ... depN.h
+
+		  We'll recompile our file when its public header changes.  When
+		  only the body of the code changes we don't recompile, only
+		  later relink;
+		- $NAME.ta: dep1.o dep2.o ... depN.o
+
+		  Make sure to include all required dependencies in the $NAME.t
+		  binary so that the later linking works properly.
+
+		So if we have file1.c, file2.c and file3.c with their respective
+		headers, where file2.c and file3.c depend of file1.c, i.e. they
+		have `#include "file.h"` in their code, and file3.c depend of
+		file2.c, the expected output is:
+
+		  file1.o file1.lo file1.to: file1.h
+		  file2.o file2.lo file2.to: file2.h
+		  file3.o file3.lo file3.to: file3.h
+
+		  file1.ta: file1.to
+		  file2.ta: file2.to
+		  file3.ta: file3.to
+
+		  file1.t-run: file1.t
+		  file2.t-run: file2.t
+		  file3.t-run: file3.t
+
+
+		  file1.o file1.lo file1.to:
+		  file2.o file2.lo file2.to: file1.h
+		  file3.o file3.lo file3.to: file1.h file2.h
+
+		  file1.ta:
+		  file2.ta: file1.o
+		  file3.ta: file1.o file2.o
+
+		This ensures that only the minimal amount of files need to get
+		recompiled, but no less.
+
+
+		Examples:
+
+		  Get deps for all files in 'src/' but 'src/main.c':
+
+		    $ sh tools/cdeps.sh `find src/*.c -not -name 'main.c'`
+
+
+		  Emit dependencies for all C files in a Git repository:
+
+		    $ sh tools/cdeps.sh `git ls-files | grep '\.c$'`
+	EOF
+}
+
+
+for flag in "$@"; do
+	case "$flag" in
+		(--)
+			break
+			;;
+		(--help)
+			usage
+			help
+			exit
+			;;
+		(*)
+			;;
+	esac
+done
+
+while getopts 'h' flag; do
+	case "$flag" in
+		(h)
+			usage
+			help
+			exit
+			;;
+		(*)
+			usage >&2
+			exit 2
+			;;
+	esac
+done
+shift $((OPTIND - 1))
+
+FILE="${1:-}"
+eval "$(assert_arg "$FILE" 'FILE')"
+
+
+
+each_f() {
+	fn="$1"
+	shift
+	for file in "$@"; do
+		f="${file%.c}"
+		"$fn" "$f"
+	done
+	printf '\n'
+}
+
+self_header_deps() {
+	printf '%s.o\t%s.lo\t%s.to:\t%s.h\n' "$1" "$1" "$1" "$1"
+}
+
+self_ta_deps() {
+	printf '%s.ta:\t%s.to\n' "$1" "$1"
+}
+
+self_trun_deps() {
+	printf '%s.t-run:\t%s.t\n' "$1" "$1"
+}
+
+deps_for() {
+	ext="$2"
+	for file in $(awk -F'"' '/^#include "/ { print $2 }' "$1.c"); do
+		if [ "$file" = 'config.h' ]; then
+			continue
+		fi
+		if [ "$(basename "$file")" = 'tests-lib.h' ]; then
+			continue
+		fi
+		f="$(dirname "$1")/$file"
+		if [ "$f" = "$1.h" ]; then
+			continue
+		fi
+		printf '%s\n' "${f%.h}$2"
+	done
+}
+
+rebuild_deps() {
+	printf '\n'
+	printf '%s.o\t%s.lo\t%s.to:' "$1" "$1" "$1"
+	printf ' %s' $(deps_for "$1" .h) | sed 's|^ $||'
+}
+
+archive_deps() {
+	printf '\n'
+	printf '%s.ta:' "$1"
+	printf ' %s' $(deps_for "$1" .o) | sed 's|^ $||'
+}
+
+
+each_f self_header_deps "$@"
+each_f self_ta_deps     "$@"
+each_f self_trun_deps   "$@"
+
+each_f rebuild_deps     "$@"
+each_f archive_deps     "$@"