Makefile: introduce infrastructure to build internal Rust library

Introduce infrastructure to build the internal Rust library. This
mirrors the infrastructure we have added to Meson in the preceding
commit. Developers can enable the infrastructure by passing the new
`WITH_RUST` build toggle.

Inspired-by: Ezekiel Newren <ezekielnewren@gmail.com>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/.gitignore b/.gitignore
index 1803023427af81f31c17f83231078e3ddcf6fe0a..0833453cf6fec00f69dad2de181e8dffba7793b7 100644 (file)
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,6 @@
 /fuzz_corpora
+/target/
+/Cargo.lock
 /GIT-BUILD-DIR
 /GIT-BUILD-OPTIONS
 /GIT-CFLAGS

diff --git a/Makefile b/Makefile
index 7e52625d7550613c811626dc49f1cfba6a6cad7c..31e79342e1d6478221f9a296796b14b23cb6e3b7 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -483,6 +483,14 @@ include shared.mak
 # Define LIBPCREDIR=/foo/bar if your PCRE header and library files are
 # in /foo/bar/include and /foo/bar/lib directories.
 #
+# == Optional Rust support ==
+#
+# Define WITH_RUST if you want to include features and subsystems written in
+# Rust into Git. For now, Rust is still an optional feature of the build
+# process. With Git 3.0 though, Rust will always be enabled.
+#
+# Building Rust code requires Cargo.
+#
 # == SHA-1 and SHA-256 defines ==
 #
 # === SHA-1 backend ===
@@ -683,6 +691,7 @@ OBJECTS =
 OTHER_PROGRAMS =
 PROGRAM_OBJS =
 PROGRAMS =
+RUST_SOURCES =
 EXCLUDED_PROGRAMS =
 SCRIPT_PERL =
 SCRIPT_PYTHON =
@@ -918,6 +927,11 @@ TEST_SHELL_PATH = $(SHELL_PATH)
 LIB_FILE = libgit.a
 XDIFF_LIB = xdiff/lib.a
 REFTABLE_LIB = reftable/libreftable.a
+ifdef DEBUG
+RUST_LIB = target/debug/libgitcore.a
+else
+RUST_LIB = target/release/libgitcore.a
+endif
 
 # xdiff and reftable libs may in turn depend on what is in libgit.a
 GITLIBS = common-main.o $(LIB_FILE) $(XDIFF_LIB) $(REFTABLE_LIB) $(LIB_FILE)
@@ -943,6 +957,15 @@ BASIC_LDFLAGS =
 ARFLAGS = rcs
 PTHREAD_CFLAGS =
 
+# Rust flags
+CARGO_ARGS =
+ifndef V
+CARGO_ARGS += --quiet
+endif
+ifndef DEBUG
+CARGO_ARGS += --release
+endif
+
 # For the 'sparse' target
 SPARSE_FLAGS ?= -std=gnu99 -D__STDC_NO_VLA__
 SP_EXTRA_FLAGS =
@@ -1475,6 +1498,8 @@ CLAR_TEST_OBJS += $(UNIT_TEST_DIR)/unit-test.o
 
 UNIT_TEST_OBJS += $(UNIT_TEST_DIR)/test-lib.o
 
+RUST_SOURCES += src/lib.rs
+
 GIT-VERSION-FILE: FORCE
        @OLD=$$(cat $@ 2>/dev/null || :) && \
        $(call version_gen,"$(shell pwd)",GIT-VERSION-FILE.in,$@) && \
@@ -1504,6 +1529,11 @@ endif
 ALL_CFLAGS = $(DEVELOPER_CFLAGS) $(CPPFLAGS) $(CFLAGS) $(CFLAGS_APPEND)
 ALL_LDFLAGS = $(LDFLAGS) $(LDFLAGS_APPEND)
 
+ifdef WITH_RUST
+BASIC_CFLAGS += -DWITH_RUST
+GITLIBS += $(RUST_LIB)
+endif
+
 ifdef SANITIZE
 SANITIZERS := $(foreach flag,$(subst $(comma),$(space),$(SANITIZE)),$(flag))
 BASIC_CFLAGS += -fsanitize=$(SANITIZE) -fno-sanitize-recover=$(SANITIZE)
@@ -2918,6 +2948,12 @@ scalar$X: scalar.o GIT-LDFLAGS $(GITLIBS)
 $(LIB_FILE): $(LIB_OBJS)
        $(QUIET_AR)$(RM) $@ && $(AR) $(ARFLAGS) $@ $^
 
+$(RUST_LIB): Cargo.toml $(RUST_SOURCES)
+       $(QUIET_CARGO)cargo build $(CARGO_ARGS)
+
+.PHONY: rust
+rust: $(RUST_LIB)
+
 $(XDIFF_LIB): $(XDIFF_OBJS)
        $(QUIET_AR)$(RM) $@ && $(AR) $(ARFLAGS) $@ $^
 
@@ -3768,6 +3804,7 @@ clean: profile-clean coverage-clean cocciclean
        $(RM) $(FUZZ_PROGRAMS)
        $(RM) $(SP_OBJ)
        $(RM) $(HCC)
+       $(RM) -r Cargo.lock target/
        $(RM) version-def.h
        $(RM) -r $(dep_dirs) $(compdb_dir) compile_commands.json
        $(RM) $(test_bindir_programs)

diff --git a/shared.mak b/shared.mak
index 5c7bc9478544c8354daacbc7a131de653faaada6..0e7492076ebc4f65990401c745aebc6bb0533830 100644 (file)
--- a/shared.mak
+++ b/shared.mak
@@ -56,6 +56,7 @@ ifndef V
        QUIET_MKDIR_P_PARENT  = @echo '   ' MKDIR -p $(@D);
 
 ## Used in "Makefile"
+       QUIET_CARGO    = @echo '   ' CARGO $@;
        QUIET_CC       = @echo '   ' CC $@;
        QUIET_AR       = @echo '   ' AR $@;
        QUIET_LINK     = @echo '   ' LINK $@;