Make.rules

# Build objects and libraries.
# ============================

# Compute the installation directory.  By default, it is same as the relative
# path to the prerequisite in the source tree.  Setting INSTALL_DIR= disables
# installation for a sub-tree (unless it is overridden deeper in the tree).
ifeq ($(flavor INSTALL_DIR),undefined)
  ifeq ($(flavor RELATIVE_INSTALL_DIR),undefined)
    RELATIVE_INSTALL_DIR = $(shell realpath --relative-to $(ROOT_DIR) $(shell pwd))
  endif
  ifdef RELATIVE_INSTALL_DIR
    INSTALL_DIR = $(abspath $(PREFIX)/$(RELATIVE_INSTALL_DIR))
    DIRS_TO_UNINSTALL += $(INSTALL_DIR)
  endif
endif

# Submodules may override SRCS.
ifeq ($(flavor SRCS),undefined)
  SRCS := $(wildcard *.c *.cpp)
endif

LOCKFILE := $(OBJECT_ROOT)/lock
FILES_TO_CLEAN += $(LOCKFILE)
# Update archives from .o files using a lock to prevent concurrent access.
.o.a:
	flock $(LOCKFILE) $(AR) rvP -U $@ $<

# Contextual variables
# ====================
# These take values that depend on the submodule being built.

# Create the directory under $(OBJECT_ROOT) corresponding to the current source
# directory.
OBJECT_DIR := $(shell realpath --relative-to $(ROOT_DIR)/src $(shell pwd))
ifeq ($(findstring ..,$(OBJECT_DIR)),..)
	OBJECT_DIR :=
else
  OBJECT_DIR := $(abspath $(OBJECT_ROOT)/$(OBJECT_DIR))
  $(shell mkdir -p $(OBJECT_DIR) >/dev/null)
  DIRS_TO_CLEAN += $(OBJECT_DIR)
endif

# Submodules may override OBJS.
ifeq ($(flavor OBJS),undefined)
  OBJS := $(patsubst %,%.o,$(basename $(SRCS)))
endif
OBJS_OUT := $(patsubst %,$(OBJECT_DIR)/%,$(OBJS))
FILES_TO_CLEAN += $(OBJS_OUT)

# Install objects, libraries, links, and programs.
# ================================================

# Submodules may set LIB to build a static library.
ifdef LIB
  # Build.
  LIB_OUT := $(OBJECT_ROOT)/$(LIB).a
  FILES_TO_CLEAN += $(LIB_OUT)
  $(LIB_OUT): $(LIB_OUT)($(LIB_DEPENDS))
  libs:: $(LIB_OUT)
  libs:: $(LIB_DEPENDS)
  # Install.
  ifdef INSTALL_DIR
    LIB_BASENAME := $(notdir $(basename $(LIB)))
    LIB_INSTALL = $(INSTALL_DIR)/$(LIB_BASENAME).a
    DIRS_TO_UNINSTALL += $(dir $(LIB_INSTALL))
    FILES_TO_UNINSTALL += $(LIB_INSTALL)
    install:: $(LIB_INSTALL)
    $(LIB_INSTALL): $(LIB_OUT)
			@mkdir -p $(dir $@)
			cp $< $@
  endif
endif

# Submodules may set SHLIB to build a dynamic library.
ifdef SHLIB
  ifdef INSTALL_DIR
    # Build.
    SHLIB_OUT := $(OBJECT_DIR)/$(SHLIB).so
    FILES_TO_CLEAN += $(SHLIB_OUT)
    $(SHLIB_OUT): $(SHLIB_DEPENDS) | $(SHLIB_EXTRA_DEPENDS)
			$(CXX) -shared -o $@ $(SHLIB_PREDEP_LDFLAGS) $^ $(SHLIB_POSTDEP_LDFLAGS) $(LDFLAGS)
    shlibs:: $(SHLIB_OUT)
    shlibs:: $(SHLIB_DEPENDS)
    # Install.
    SHLIB_INSTALL = $(INSTALL_DIR)/$(SHLIB).so
    DIRS_TO_UNINSTALL += $(dir $(SHLIB_INSTALL))
    FILES_TO_UNINSTALL += $(SHLIB_INSTALL)
    install:: $(SHLIB_INSTALL)
    $(SHLIB_INSTALL): $(SHLIB_OUT)
			@mkdir -p $(dir $@)
			cp $< $@
  endif
endif

# Submodules may set EXPORTED_HEADERS to export header files.
ifdef EXPORTED_HEADERS
  ifdef HEADER_INSTALL_DIR
    HEADERS_INSTALL = $(addprefix $(HEADER_INSTALL_DIR)/, $(EXPORTED_HEADERS))
    DIRS_TO_UNINSTALL += $(dir $(HEADERS_INSTALL))
    FILES_TO_UNINSTALL += $(HEADERS_INSTALL)
    install:: $(HEADERS_INSTALL)
    $(HEADER_INSTALL_DIR)/%.hpp : %.hpp
			@mkdir -p $(dir $@)
      ifdef SYMLINK_INTERFACES
			  ln -sf $(abspath $<) $@
      else
			  cp $< $@
      endif
    $(HEADER_INSTALL_DIR)/%.hxx : %.hxx
			@mkdir -p $(dir $@)
      ifdef SYMLINK_INTERFACES
			  ln -sf $(abspath $<) $@
      else
			  cp $< $@
      endif
  endif
endif

# Submodules may override LINKS.
#
# The following evaluates the .link file contents as a make expression to
# compute the link target.
define define_link_target =
  LINK_TARGET_$1 := $(shell cat $1)
endef

ifeq ($(flavor LINKS),undefined)
  LINKS = $(wildcard *.link)
endif
ifdef LINKS
  ifdef INSTALL_DIR
    LINKS_NOEXT := $(patsubst %.link,%,$(LINKS))
    # Do not update FILES_TO_CLEAN.  There are no intermediate files.
    LINKS_INSTALL = $(addprefix $(INSTALL_DIR)/, $(LINKS_NOEXT))
    DIRS_TO_UNINSTALL += $(dir $(LINKS_INSTALL))
    FILES_TO_UNINSTALL += $(LINKS_INSTALL)
    install:: $(LINKS_INSTALL)
    $(foreach link,$(LINKS),$(eval $(call define_link_target,$(link))))
    $(INSTALL_DIR)/% : %.link
			@if [ -n "$(LINK_TARGET_$<)" ]; then \
        mkdir -p $(dir $@); \
        echo ln -sf $(LINK_TARGET_$<) $@; \
        ln -sf $(LINK_TARGET_$<) $@; \
      else \
        echo 1>&2 "Skipping installation of link $@ because it has no target."; \
      fi
  endif
endif

# Submodules may override VARS.
#
# This type of file is processed exactly like a link, except that instead of a
# link, a regular file containing the expanded variable is created.
define define_var_target =
  VAR_VALUE$1 := $(shell cat $1)
endef

ifeq ($(flavor VARS),undefined)
  VARS = $(wildcard *.var)
endif
ifdef VARS
  ifdef INSTALL_DIR
    VARS_NOEXT := $(patsubst %.var,%,$(VARS))
    # Do not update FILES_TO_CLEAN.  There are no intermediate files.
    VARS_INSTALL = $(addprefix $(INSTALL_DIR)/, $(VARS_NOEXT))
    DIRS_TO_UNINSTALL += $(dir $(VARS_INSTALL))
    FILES_TO_UNINSTALL += $(VARS_INSTALL)
    install:: $(VARS_INSTALL)
    $(foreach var,$(VARS),$(eval $(call define_var_target,$(var))))
    $(INSTALL_DIR)/% : %.var
			@mkdir -p $(dir $@)
			echo $(VAR_VALUE$<) > $@
  endif
endif

# Submodules may override SCRIPTS.  Scripts are copied.
ifeq ($(flavor SCRIPTS),undefined)
  SCRIPTS = $(shell ls *.script 2>/dev/null)
endif
ifdef SCRIPTS
  ifdef INSTALL_DIR
    SCRIPTS_NOEXT := $(patsubst %.script,%,$(SCRIPTS))
    # Do not update FILES_TO_CLEAN.  There are no intermediate files.
    SCRIPTS_INSTALL = $(addprefix $(INSTALL_DIR)/, $(SCRIPTS_NOEXT))
    DIRS_TO_UNINSTALL += $(dir $(SCRIPTS_INSTALL))
    FILES_TO_UNINSTALL += $(SCRIPTS_INSTALL)
    install:: $(SCRIPTS_INSTALL)
    $(INSTALL_DIR)/% : %.script
			@mkdir -p $(dir $@)
			cp $< $@
  endif
endif

# Submodules may override PYTHONFILES.
ifeq ($(flavor PYTHONFILES),undefined)
  PYTHONFILES = $(wildcard *.py)
endif
ifdef PYTHONFILES
  ifdef INSTALL_DIR
    # Do not update FILES_TO_CLEAN.  There are no intermediate files.
    PYTHONFILES_INSTALL = $(addprefix $(INSTALL_DIR)/, $(PYTHONFILES))
    DIRS_TO_UNINSTALL += $(dir $(PYTHONFILES_INSTALL))
    FILES_TO_UNINSTALL += $(PYTHONFILES_INSTALL)
    install:: $(PYTHONFILES_INSTALL)
    $(INSTALL_DIR)/%.py : %.py
			@mkdir -p $(dir $@)
      ifdef SYMLINK_INTERFACES
				ln -sf $(abspath $<) $@
      else
				cp $< $@
      endif
  endif
endif

# Sort removes duplicates.  Sort by reverse depth.
reverse = $(shell printf "%s\n" $(strip $1) | tac)
FILES_TO_CLEAN := $(call reverse, $(sort $(foreach path,$(FILES_TO_CLEAN),$(abspath $(path)))))
DIRS_TO_REC_CLEAN := $(call reverse, $(sort $(foreach path,$(DIRS_TO_REC_CLEAN),$(abspath $(path)))))
DIRS_TO_CLEAN := $(call reverse, $(sort $(foreach path,$(DIRS_TO_CLEAN),$(abspath $(path)))))
FILES_TO_UNINSTALL := $(call reverse, $(sort $(foreach path,$(FILES_TO_UNINSTALL),$(abspath $(path)))))
DIRS_TO_REC_UNINSTALL := $(call reverse, $(sort $(foreach path,$(DIRS_TO_REC_UNINSTALL),$(abspath $(path)))))
DIRS_TO_UNINSTALL := $(call reverse, $(sort $(foreach path,$(DIRS_TO_UNINSTALL),$(abspath $(path)))))

safe-clean ::
	$(call clean_files,$(FILES_TO_CLEAN),rm -f)
	$(call clean_files,$(DIRS_TO_REC_CLEAN),rm -rf)
	$(call clean_files,$(DIRS_TO_CLEAN),rmdir)

uninstall ::
	$(call clean_files,$(FILES_TO_UNINSTALL),rm -f)
	$(call clean_files,$(DIRS_TO_REC_UNINSTALL),rm -rf)
	$(call clean_files,$(DIRS_TO_UNINSTALL),rmdir)