package/pkg-rebar.mk - buildroot - Git at Google

 ################################################################################
 # rebar package infrastructure for Erlang packages
 #
 # This file implements an infrastructure that eases development of
 # package .mk files for rebar packages.  It should be used for all
 # packages that use rebar as their build system.
 #
 # In terms of implementation, this rebar infrastructure requires the
 # .mk file to only specify metadata information about the package:
 # name, version, download URL, etc.
 #
 # We still allow the package .mk file to override what the different
 # steps are doing, if needed. For example, if <PKG>_BUILD_CMDS is
 # already defined, it is used as the list of commands to perform to
 # build the package, instead of the default rebar behaviour. The
 # package can also define some post operation hooks.
 #
 ################################################################################

 # Directories to store rebar dependencies in.
 #
 # These directories actually only contain symbolic links to Erlang
 # applications in either $(HOST_DIR) or $(STAGING_DIR).  One needs
 # them to avoid rebar complaining about missing dependencies, as this
 # infrastructure tells rebar to NOT download dependencies during
 # the build stage.
 #
 REBAR_HOST_DEPS_DIR = $(HOST_DIR)/usr/share/rebar/deps
 REBAR_TARGET_DEPS_DIR = $(STAGING_DIR)/usr/share/rebar/deps

 # Tell rebar where to find the dependencies
 #
 REBAR_HOST_DEPS_ENV = \
 	ERL_COMPILER_OPTIONS='{i, "$(REBAR_HOST_DEPS_DIR)"}' \
 	ERL_EI_LIBDIR=$(HOST_DIR)/usr/lib/erlang/lib/erl_interface-$(ERLANG_EI_VSN)/lib
 REBAR_TARGET_DEPS_ENV = \
 	ERL_COMPILER_OPTIONS='{i, "$(REBAR_TARGET_DEPS_DIR)"}' \
 	ERL_EI_LIBDIR=$(STAGING_DIR)/usr/lib/erlang/lib/erl_interface-$(ERLANG_EI_VSN)/lib

 ################################################################################
 # Helper functions
 ################################################################################

 # Install an Erlang application from $(@D).
 #
 # i.e., define a recipe that installs the "bin ebin priv $(2)" directories
 # from $(@D) to $(1)$($(PKG)_ERLANG_LIBDIR).
 #
 #  argument 1 should typically be $(HOST_DIR), $(TARGET_DIR),
 #	      or $(STAGING_DIR).
 #  argument 2 is typically empty when installing in $(TARGET_DIR) and
 #             "include" when installing in $(HOST_DIR) or
 #             $(STAGING_DIR).
 #
 # Note: calling this function must be done with $$(call ...) because it
 # expands package-related variables.
 #
 define install-erlang-directories
 	$(INSTALL) -d $(1)/$($(PKG)_ERLANG_LIBDIR)
 	for dir in bin ebin priv $(2); do                               \
 		if test -d $(@D)/$$dir; then                            \
 			cp -r $(@D)/$$dir $(1)$($(PKG)_ERLANG_LIBDIR);  \
 		fi;                                                     \
 	done
 endef

 # Setup a symbolic link in rebar's deps_dir to the actual location
 # where an Erlang application is installed.
 #
 # i.e., define a recipe that creates a symbolic link
 # from $($(PKG)_REBAR_DEPS_DIR)/$($(PKG)_ERLANG_APP)
 # to $(1)$($(PKG)_ERLANG_LIBDIR).
 #
 # For target packages for example, one uses this to setup symbolic
 # links from $(STAGING_DIR)/usr/share/rebar/deps/<erlang-app> to
 # $(STAGING_DIR)/usr/lib/erlang/lib/<erlang-app>-<version>. This
 # infrastructure points rebar at the former in order to tell rebar to
 # NOT download dependencies during the build stage, and instead use
 # the already available dependencies.
 #
 # Therefore,
 #  argument 1 is $(HOST_DIR) (for host packages) or
 #	      $(STAGING_DIR) (for target packages).
 #
 #  argument 2 is HOST (for host packages) or
 #	      TARGET (for target packages).
 #
 # Note: calling this function must be done with $$(call ...) because it
 # expands package-related variables.
 #
 define install-rebar-deps
 	$(INSTALL) -d $(REBAR_$(2)_DEPS_DIR)
 	ln -f -s $(1)/$($(PKG)_ERLANG_LIBDIR) \
 		$(REBAR_$(2)_DEPS_DIR)/$($(PKG)_ERLANG_APP)
 endef

 ################################################################################
 # inner-rebar-package -- defines how the configuration, compilation
 # and installation of a rebar package should be done, implements a few
 # hooks to tune the build process according to rebar specifities, and
 # calls the generic package infrastructure to generate the necessary
 # make targets.
 #
 #  argument 1 is the lowercase package name
 #  argument 2 is the uppercase package name, including a HOST_ prefix
 #             for host packages
 #  argument 3 is the uppercase package name, without the HOST_ prefix
 #             for host packages
 #  argument 4 is the type (target or host)
 #
 ################################################################################

 define inner-rebar-package

 # Extract just the raw package name, lowercase without the leading
 # erlang- or host- prefix, as this is used by rebar to find the
 # dependencies a package specifies.
 #
 $(2)_ERLANG_APP = $(subst -,_,$(patsubst erlang-%,%,$(patsubst host-%,%,$(1))))

 # Path where to store the package's libs, relative to either $(HOST_DIR)
 # for host packages, or $(STAGING_DIR) for target packages.
 #
 $(2)_ERLANG_LIBDIR = \
 	/usr/lib/erlang/lib/$$($$(PKG)_ERLANG_APP)-$$($$(PKG)_VERSION)

 # If a host package, inherit <pkg>_USE_BUNDLED_REBAR from the target
 # package, if not explicitly defined. Otherwise, default to NO.
 ifndef $(2)_USE_BUNDLED_REBAR
  ifdef $(3)_USE_BUNDLED_REBAR
   $(2)_USE_BUNDLED_REBAR = $$($(3)_USE_BUNDLED_REBAR)
  else
   $(2)_USE_BUNDLED_REBAR ?= NO
  endif
 endif

 # If a host package, inherit <pkg>_USE_AUTOCONF from the target
 # package, if not explicitly defined. Otherwise, default to NO.
 ifndef $(2)_USE_AUTOCONF
  ifdef $(3)_USE_AUTOCONF
   $(2)_USE_AUTOCONF = $$($(3)_USE_AUTOCONF)
  else
   $(2)_USE_AUTOCONF ?= NO
  endif
 endif

 # Define the build and install commands
 #
 ifeq ($(4),target)

 # Target packages need the erlang interpreter on the target
 $(2)_DEPENDENCIES += erlang

 # Used only if the package uses autotools underneath; otherwise, ignored
 $(2)_CONF_ENV += $$(REBAR_TARGET_DEPS_ENV)

 ifndef $(2)_BUILD_CMDS
 define $(2)_BUILD_CMDS
 	(cd $$(@D); \
 		CC="$$(TARGET_CC)" \
 		CXX="$$(TARGET_CXX)" \
 		CFLAGS="$$(TARGET_CFLAGS)" \
 		CXXFLAGS="$$(TARGET_CXXFLAGS)" \
 		LDFLAGS="$$(TARGET_LDFLAGS)" \
 		$$(REBAR_TARGET_DEPS_ENV) \
 		$$(TARGET_MAKE_ENV) \
 		$$($$(PKG)_REBAR_ENV) $$($$(PKG)_REBAR) deps_dir=$$(REBAR_TARGET_DEPS_DIR) compile \
 	)
 endef
 endif

 # We need to double-$ the 'call' because it wants to expand
 # package-related variables
 ifndef $(2)_INSTALL_STAGING_CMDS
 define $(2)_INSTALL_STAGING_CMDS
 	$$(call install-erlang-directories,$$(STAGING_DIR),include)
 	$$(call install-rebar-deps,$$(STAGING_DIR),TARGET)
 endef
 endif

 # We need to double-$ the 'call' because it wants to expand
 # package-related variables
 ifndef $(2)_INSTALL_TARGET_CMDS
 define $(2)_INSTALL_TARGET_CMDS
 	$$(call install-erlang-directories,$$(TARGET_DIR))
 endef
 endif

 else # !target

 # Host packages need the erlang interpreter on the host
 $(2)_DEPENDENCIES += host-erlang

 # Used only if the package uses autotools underneath; otherwise, ignored
 $(2)_CONF_ENV += $$(REBAR_HOST_DEPS_ENV)

 ifndef $(2)_BUILD_CMDS
 define $(2)_BUILD_CMDS
 	(cd $$(@D); \
 		CC="$$(HOSTCC)" \
 		CFLAGS="$$(HOST_CFLAGS)" \
 		LDFLAGS="$$(HOST_LDFLAGS)" \
 		$$(REBAR_HOST_DEPS_ENV) \
 		$$(HOST_MAKE_ENV) \
 		$$($$(PKG)_REBAR_ENV) $$($$(PKG)_REBAR) deps_dir=$$(REBAR_HOST_DEPS_DIR) compile \
 	)
 endef
 endif

 # We need to double-$ the 'call' because it wants to expand
 # package-related variables
 ifndef $(2)_INSTALL_CMDS
 define $(2)_INSTALL_CMDS
 	$$(call install-erlang-directories,$$(HOST_DIR),include)
 	$$(call install-rebar-deps,$$(HOST_DIR),HOST)
 endef
 endif

 endif # !target

 # Whether to use the generic rebar or the package's bundled rebar
 #
 ifeq ($$($(2)_USE_BUNDLED_REBAR),YES)
 $(2)_REBAR = ./rebar
 else
 $(2)_REBAR = rebar
 $(2)_DEPENDENCIES += host-erlang-rebar
 endif

 # The package sub-infra to use
 #
 ifeq ($$($(2)_USE_AUTOCONF),YES)
 $(call inner-autotools-package,$(1),$(2),$(3),$(4))
 else
 $(call inner-generic-package,$(1),$(2),$(3),$(4))
 endif

 endef # inner-rebar-package

 rebar-package = $(call inner-rebar-package,$(pkgname),$(call UPPERCASE,$(pkgname)),$(call UPPERCASE,$(pkgname)),target)
 host-rebar-package = $(call inner-rebar-package,host-$(pkgname),$(call UPPERCASE,host-$(pkgname)),$(call UPPERCASE,$(pkgname)),host)
	################################################################################
	# rebar package infrastructure for Erlang packages
	#
	# This file implements an infrastructure that eases development of
	# package .mk files for rebar packages. It should be used for all
	# packages that use rebar as their build system.
	#
	# In terms of implementation, this rebar infrastructure requires the
	# .mk file to only specify metadata information about the package:
	# name, version, download URL, etc.
	#
	# We still allow the package .mk file to override what the different
	# steps are doing, if needed. For example, if <PKG>_BUILD_CMDS is
	# already defined, it is used as the list of commands to perform to
	# build the package, instead of the default rebar behaviour. The
	# package can also define some post operation hooks.
	#
	################################################################################

	# Directories to store rebar dependencies in.
	#
	# These directories actually only contain symbolic links to Erlang
	# applications in either $(HOST_DIR) or $(STAGING_DIR). One needs
	# them to avoid rebar complaining about missing dependencies, as this
	# infrastructure tells rebar to NOT download dependencies during
	# the build stage.
	#
	REBAR_HOST_DEPS_DIR = $(HOST_DIR)/usr/share/rebar/deps
	REBAR_TARGET_DEPS_DIR = $(STAGING_DIR)/usr/share/rebar/deps

	# Tell rebar where to find the dependencies
	#
	REBAR_HOST_DEPS_ENV = \
	ERL_COMPILER_OPTIONS='{i, "$(REBAR_HOST_DEPS_DIR)"}' \
	ERL_EI_LIBDIR=$(HOST_DIR)/usr/lib/erlang/lib/erl_interface-$(ERLANG_EI_VSN)/lib
	REBAR_TARGET_DEPS_ENV = \
	ERL_COMPILER_OPTIONS='{i, "$(REBAR_TARGET_DEPS_DIR)"}' \
	ERL_EI_LIBDIR=$(STAGING_DIR)/usr/lib/erlang/lib/erl_interface-$(ERLANG_EI_VSN)/lib

	################################################################################
	# Helper functions
	################################################################################

	# Install an Erlang application from $(@D).
	#
	# i.e., define a recipe that installs the "bin ebin priv $(2)" directories
	# from $(@D) to $(1)$($(PKG)_ERLANG_LIBDIR).
	#
	# argument 1 should typically be $(HOST_DIR), $(TARGET_DIR),
	# or $(STAGING_DIR).
	# argument 2 is typically empty when installing in $(TARGET_DIR) and
	# "include" when installing in $(HOST_DIR) or
	# $(STAGING_DIR).
	#
	# Note: calling this function must be done with $$(call ...) because it
	# expands package-related variables.
	#
	define install-erlang-directories
	$(INSTALL) -d $(1)/$($(PKG)_ERLANG_LIBDIR)
	for dir in bin ebin priv $(2); do \
	if test -d $(@D)/$$dir; then \
	cp -r $(@D)/$$dir $(1)$($(PKG)_ERLANG_LIBDIR); \
	fi; \
	done
	endef

	# Setup a symbolic link in rebar's deps_dir to the actual location
	# where an Erlang application is installed.
	#
	# i.e., define a recipe that creates a symbolic link
	# from $($(PKG)_REBAR_DEPS_DIR)/$($(PKG)_ERLANG_APP)
	# to $(1)$($(PKG)_ERLANG_LIBDIR).
	#
	# For target packages for example, one uses this to setup symbolic
	# links from $(STAGING_DIR)/usr/share/rebar/deps/<erlang-app> to
	# $(STAGING_DIR)/usr/lib/erlang/lib/<erlang-app>-<version>. This
	# infrastructure points rebar at the former in order to tell rebar to
	# NOT download dependencies during the build stage, and instead use
	# the already available dependencies.
	#
	# Therefore,
	# argument 1 is $(HOST_DIR) (for host packages) or
	# $(STAGING_DIR) (for target packages).
	#
	# argument 2 is HOST (for host packages) or
	# TARGET (for target packages).
	#
	# Note: calling this function must be done with $$(call ...) because it
	# expands package-related variables.
	#
	define install-rebar-deps
	$(INSTALL) -d $(REBAR_$(2)_DEPS_DIR)
	ln -f -s $(1)/$($(PKG)_ERLANG_LIBDIR) \
	$(REBAR_$(2)_DEPS_DIR)/$($(PKG)_ERLANG_APP)
	endef

	################################################################################
	# inner-rebar-package -- defines how the configuration, compilation
	# and installation of a rebar package should be done, implements a few
	# hooks to tune the build process according to rebar specifities, and
	# calls the generic package infrastructure to generate the necessary
	# make targets.
	#
	# argument 1 is the lowercase package name
	# argument 2 is the uppercase package name, including a HOST_ prefix
	# for host packages
	# argument 3 is the uppercase package name, without the HOST_ prefix
	# for host packages
	# argument 4 is the type (target or host)
	#
	################################################################################

	define inner-rebar-package

	# Extract just the raw package name, lowercase without the leading
	# erlang- or host- prefix, as this is used by rebar to find the
	# dependencies a package specifies.
	#
	$(2)_ERLANG_APP = $(subst -,_,$(patsubst erlang-%,%,$(patsubst host-%,%,$(1))))

	# Path where to store the package's libs, relative to either $(HOST_DIR)
	# for host packages, or $(STAGING_DIR) for target packages.
	#
	$(2)_ERLANG_LIBDIR = \
	/usr/lib/erlang/lib/$$($$(PKG)_ERLANG_APP)-$$($$(PKG)_VERSION)

	# If a host package, inherit <pkg>_USE_BUNDLED_REBAR from the target
	# package, if not explicitly defined. Otherwise, default to NO.
	ifndef $(2)_USE_BUNDLED_REBAR
	ifdef $(3)_USE_BUNDLED_REBAR
	$(2)_USE_BUNDLED_REBAR = $$($(3)_USE_BUNDLED_REBAR)
	else
	$(2)_USE_BUNDLED_REBAR ?= NO
	endif
	endif

	# If a host package, inherit <pkg>_USE_AUTOCONF from the target
	# package, if not explicitly defined. Otherwise, default to NO.
	ifndef $(2)_USE_AUTOCONF
	ifdef $(3)_USE_AUTOCONF
	$(2)_USE_AUTOCONF = $$($(3)_USE_AUTOCONF)
	else
	$(2)_USE_AUTOCONF ?= NO
	endif
	endif

	# Define the build and install commands
	#
	ifeq ($(4),target)

	# Target packages need the erlang interpreter on the target
	$(2)_DEPENDENCIES += erlang

	# Used only if the package uses autotools underneath; otherwise, ignored
	$(2)_CONF_ENV += $$(REBAR_TARGET_DEPS_ENV)

	ifndef $(2)_BUILD_CMDS
	define $(2)_BUILD_CMDS
	(cd $$(@D); \
	CC="$$(TARGET_CC)" \
	CXX="$$(TARGET_CXX)" \
	CFLAGS="$$(TARGET_CFLAGS)" \
	CXXFLAGS="$$(TARGET_CXXFLAGS)" \
	LDFLAGS="$$(TARGET_LDFLAGS)" \
	$$(REBAR_TARGET_DEPS_ENV) \
	$$(TARGET_MAKE_ENV) \
	$$($$(PKG)_REBAR_ENV) $$($$(PKG)_REBAR) deps_dir=$$(REBAR_TARGET_DEPS_DIR) compile \
	)
	endef
	endif

	# We need to double-$ the 'call' because it wants to expand
	# package-related variables
	ifndef $(2)_INSTALL_STAGING_CMDS
	define $(2)_INSTALL_STAGING_CMDS
	$$(call install-erlang-directories,$$(STAGING_DIR),include)
	$$(call install-rebar-deps,$$(STAGING_DIR),TARGET)
	endef
	endif

	# We need to double-$ the 'call' because it wants to expand
	# package-related variables
	ifndef $(2)_INSTALL_TARGET_CMDS
	define $(2)_INSTALL_TARGET_CMDS
	$$(call install-erlang-directories,$$(TARGET_DIR))
	endef
	endif

	else # !target

	# Host packages need the erlang interpreter on the host
	$(2)_DEPENDENCIES += host-erlang

	# Used only if the package uses autotools underneath; otherwise, ignored
	$(2)_CONF_ENV += $$(REBAR_HOST_DEPS_ENV)

	ifndef $(2)_BUILD_CMDS
	define $(2)_BUILD_CMDS
	(cd $$(@D); \
	CC="$$(HOSTCC)" \
	CFLAGS="$$(HOST_CFLAGS)" \
	LDFLAGS="$$(HOST_LDFLAGS)" \
	$$(REBAR_HOST_DEPS_ENV) \
	$$(HOST_MAKE_ENV) \
	$$($$(PKG)_REBAR_ENV) $$($$(PKG)_REBAR) deps_dir=$$(REBAR_HOST_DEPS_DIR) compile \
	)
	endef
	endif

	# We need to double-$ the 'call' because it wants to expand
	# package-related variables
	ifndef $(2)_INSTALL_CMDS
	define $(2)_INSTALL_CMDS
	$$(call install-erlang-directories,$$(HOST_DIR),include)
	$$(call install-rebar-deps,$$(HOST_DIR),HOST)
	endef
	endif

	endif # !target

	# Whether to use the generic rebar or the package's bundled rebar
	#
	ifeq ($$($(2)_USE_BUNDLED_REBAR),YES)
	$(2)_REBAR = ./rebar
	else
	$(2)_REBAR = rebar
	$(2)_DEPENDENCIES += host-erlang-rebar
	endif

	# The package sub-infra to use
	#
	ifeq ($$($(2)_USE_AUTOCONF),YES)
	$(call inner-autotools-package,$(1),$(2),$(3),$(4))
	else
	$(call inner-generic-package,$(1),$(2),$(3),$(4))
	endif

	endef # inner-rebar-package

	rebar-package = $(call inner-rebar-package,$(pkgname),$(call UPPERCASE,$(pkgname)),$(call UPPERCASE,$(pkgname)),target)
	host-rebar-package = $(call inner-rebar-package,host-$(pkgname),$(call UPPERCASE,host-$(pkgname)),$(call UPPERCASE,$(pkgname)),host)