makefile.detect

#This file is part of SECONDO.
#
#Copyright (C) 2004, University in Hagen, Department of Computer Science,
#Database Systems for New Applications.
#
#SECONDO is free software; you can redistribute it and/or modify
#it under the terms of the GNU General Public License as published by
#the Free Software Foundation; either version 2 of the License, or
#(at your option) any later version.
#
#SECONDO is distributed in the hope that it will be useful,
#but WITHOUT ANY WARRANTY; without even the implied warranty of
#MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#GNU General Public License for more details.
#
#You should have received a copy of the GNU General Public License
#along with SECONDO; if not, write to the Free Software
#Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
########################################################################
#
# SECONDO build environment detection.
#
# This is the single place where the build configuration is derived from the
# tools installed on this machine. makefile.env includes it before anything
# else, so a plain "make" in a fresh checkout configures itself -- no shell
# has to be sourced first.
#
# It can also be run on its own:
#
#   make -s -f makefile.detect print-vars
#
# Every variable is only assigned when it does not already have a value, so an
# exported variable or a "make VAR=..." override always wins.
#
########################################################################

# Where this file lives -- captured before anything else is included, because
# $(MAKEFILE_LIST) grows. This is the root of the SECONDO tree.
SECONDO_DETECT_MK := $(abspath $(lastword $(MAKEFILE_LIST)))

# The whole block below runs exactly once per "make" tree: the results are
# exported, and this sentinel stops every recursive $(MAKE) -C from probing the
# machine again. A single sentinel rather than one guard per variable, because
# "ifndef" is also true for an exported-but-empty variable -- per-variable
# guards would re-probe every negative result in all ~260 sub-makes.
ifndef SECONDO_DETECTED

# --- the SECONDO tree ------------------------------------------------------
ifndef SECONDO_BUILD_DIR
SECONDO_BUILD_DIR := $(patsubst %/,%,$(dir $(SECONDO_DETECT_MK)))
endif

# --- platform --------------------------------------------------------------
SECONDO_UNAME_S := $(shell uname -s)
SECONDO_UNAME_M := $(shell uname -m)

ifndef SECONDO_PLATFORM
ifeq ($(SECONDO_UNAME_S),Darwin)
  SECONDO_PLATFORM := mac_osx
else
ifeq ($(SECONDO_UNAME_S),Linux)
  ifneq (,$(filter $(SECONDO_UNAME_M),x86_64 amd64 aarch64 arm64))
    SECONDO_PLATFORM := linux64
  else
    SECONDO_PLATFORM := linux
  endif
else
  SECONDO_PLATFORM := linux64
endif
endif
endif

# --- Homebrew prefix (macOS) -----------------------------------------------
# Differs by architecture: Apple Silicon uses /opt/homebrew, Intel /usr/local.
# Ask brew once, fall back to the architecture default. Guarded by the sentinel
# above, so this fork happens once per build rather than once per sub-make.
ifeq ($(SECONDO_PLATFORM),mac_osx)
ifndef HOMEBREW_PREFIX
  HOMEBREW_PREFIX := $(shell brew --prefix 2>/dev/null)
  ifeq ($(strip $(HOMEBREW_PREFIX)),)
    ifeq ($(SECONDO_UNAME_M),arm64)
      HOMEBREW_PREFIX := /opt/homebrew
    else
      HOMEBREW_PREFIX := /usr/local
    endif
  endif
endif
endif

# --- generic probes --------------------------------------------------------
# Prefixes that are searched for headers and libraries. On Linux $(HOMEBREW_PREFIX)
# is empty and drops out of the list.
SECONDO_LIB_PREFIXES := /usr /usr/local $(HOMEBREW_PREFIX)

# $(call secondo-have-lib,<header>,<libname>) -- non-empty when both the header
# and a matching library exist below one of the prefixes above. The "lib/*/"
# branch covers Debian multiarch (/usr/lib/x86_64-linux-gnu).
secondo-have-lib = $(firstword $(foreach p,$(SECONDO_LIB_PREFIXES),\
    $(if $(wildcard $(p)/include/$(1)),\
      $(wildcard $(p)/lib/lib$(2).* $(p)/lib/*/lib$(2).*))))

# $(call secondo-brew-opt,<formula names>,<header below include/>) -- the prefix
# of the first keg-only formula that is actually installed. Homebrew does not
# symlink keg-only formulae into $(HOMEBREW_PREFIX), so they have to be named
# explicitly. Probing the directory beats calling "brew --prefix <formula>":
# same answer, no fork.
secondo-brew-opt = $(firstword $(foreach f,$(1),\
    $(if $(wildcard $(HOMEBREW_PREFIX)/opt/$(f)/include/$(2)),$(HOMEBREW_PREFIX)/opt/$(f))))

# --- SWI-Prolog ------------------------------------------------------------
# The swipl binary is the single source of truth: --dump-runtime-variables
# reports the include and library directories together, so they cannot drift
# from the libswipl that actually gets linked. The embedded optimizer links
# libswipl in -pl mode; it needs no JPL (that was only the retired OptServer).
ifndef SECONDO_SWIPL
SECONDO_SWIPL := $(shell command -v swipl 2>/dev/null || command -v pl 2>/dev/null)
endif

# Output is shell syntax (PLBASE="/usr/lib/swi-prolog";), so strip the quotes
# and trailing semicolons and read it with $(filter).
SECONDO_PL_DUMP := $(if $(SECONDO_SWIPL),\
    $(shell $(SECONDO_SWIPL) --dump-runtime-variables 2>/dev/null | sed -e 's/;$$//' -e 's/"//g'))
secondo-pl-get = $(patsubst $(1)=%,%,$(filter $(1)=%,$(SECONDO_PL_DUMP)))

ifndef SWI_HOME_DIR
SWI_HOME_DIR := $(call secondo-pl-get,PLBASE)
endif
ifndef PL_LIB_DIR
PL_LIB_DIR := $(call secondo-pl-get,PLLIBDIR)
endif
ifndef PL_DLL_DIR
PL_DLL_DIR := $(PL_LIB_DIR)
endif
ifndef PL_INCLUDE_DIR
PL_INCLUDE_DIR := $(if $(SWI_HOME_DIR),$(SWI_HOME_DIR)/include)
endif
ifndef PL_LIB
PL_LIB := $(if $(SWI_HOME_DIR),swipl)
endif

# --- Java (JDK home) -------------------------------------------------------
ifndef J2SDK_ROOT
ifeq ($(SECONDO_PLATFORM),mac_osx)
J2SDK_ROOT := $(shell /usr/libexec/java_home 2>/dev/null)
else
# Resolve the symlink chain (Debian alternatives point at the real JDK) and
# strip /bin/<tool> to get the JDK root.
J2SDK_ROOT := $(patsubst %/bin/java,%,$(patsubst %/bin/javac,%,\
    $(realpath $(shell command -v javac 2>/dev/null || command -v java 2>/dev/null))))
endif
endif

# --- Berkeley DB -----------------------------------------------------------
ifeq ($(SECONDO_PLATFORM),mac_osx)
SECONDO_BDB_PREFIXES := $(HOMEBREW_PREFIX)/opt/berkeley-db $(HOMEBREW_PREFIX)/opt/berkeley-db@5 \
                        /opt/local /usr/local/opt/berkeley-db /usr/local /usr
else
SECONDO_BDB_PREFIXES := /usr /usr/local
endif

ifndef BERKELEY_DB_DIR
BERKELEY_DB_DIR := $(firstword \
    $(foreach p,$(SECONDO_BDB_PREFIXES),$(if $(wildcard $(p)/include/db_cxx.h),$(p))) /usr)
endif
ifndef BERKELEY_DB_LIB
BERKELEY_DB_LIB := db_cxx
endif

# --- Homebrew keg-only prefixes (macOS) ------------------------------------
# readline, jpeg, flex and libxml2 are keg-only, i.e. Homebrew does NOT symlink
# their headers and libraries into $(HOMEBREW_PREFIX). The SDK used to ship
# these; without it the makefiles have to be pointed at the formula prefixes so
# that the optimizer (libreadline) and the jpeg-using algebras link.
ifeq ($(SECONDO_PLATFORM),mac_osx)
ifndef SECONDO_READLINE_DIR
SECONDO_READLINE_DIR := $(call secondo-brew-opt,readline,readline/readline.h)
endif
ifndef SECONDO_JPEG_DIR
SECONDO_JPEG_DIR := $(call secondo-brew-opt,jpeg-turbo jpeg,jpeglib.h)
endif
# FlexLexer.h MUST come from the same flex that generated the C++ scanners
# (NLLex, SecLex), or the LexerInput/LexerOutput signatures mismatch. macOS
# ships an old flex in the SDK, so point at the Homebrew one.
ifndef SECONDO_FLEX_DIR
SECONDO_FLEX_DIR := $(call secondo-brew-opt,flex,FlexLexer.h)
endif
ifndef SECONDO_LIBXML2_DIR
SECONDO_LIBXML2_DIR := $(call secondo-brew-opt,libxml2,libxml2/libxml/parser.h)
endif

# --- link-time library search path (macOS) ---------------------------------
# Homebrew installs its libraries (boost, ...) under $(HOMEBREW_PREFIX)/lib,
# which is not a default linker path, and the keg-only formulae under their own
# prefixes. Several tool makefiles link without the platform LDFLAGS, so rather
# than patching each one, put the directories on LIBRARY_PATH: the compiler
# driver adds them to every link. Exported below, so this reaches every recipe
# and sub-make without a shell having to be sourced first.
secondo-empty :=
secondo-space := $(secondo-empty) $(secondo-empty)

SECONDO_LIB_PATHS := $(wildcard $(HOMEBREW_PREFIX)/lib \
    $(SECONDO_READLINE_DIR:%=%/lib) $(SECONDO_JPEG_DIR:%=%/lib) \
    $(SECONDO_LIBXML2_DIR:%=%/lib) $(SECONDO_FLEX_DIR:%=%/lib))

ifneq ($(strip $(SECONDO_LIB_PATHS)),)
LIBRARY_PATH := $(subst $(secondo-space),:,$(strip $(SECONDO_LIB_PATHS)))$(if $(LIBRARY_PATH),:$(LIBRARY_PATH))
endif
endif

# --- optional libraries ----------------------------------------------------
# GNU recode: header and library below a prefix that is searched anyway.
ifndef SECONDO_HAS_RECODE
ifneq ($(SECONDO_PLATFORM),android)
SECONDO_HAS_RECODE := $(if $(call secondo-have-lib,recode.h,recode),yes)
endif
endif

# --- publish ---------------------------------------------------------------
SECONDO_DETECTED := 1

endif # SECONDO_DETECTED

# The variables the build and the runtime care about, in one place.
SECONDO_DETECT_VARS := \
	SECONDO_BUILD_DIR \
	SECONDO_PLATFORM \
	HOMEBREW_PREFIX \
	SWI_HOME_DIR \
	PL_LIB_DIR \
	PL_DLL_DIR \
	PL_INCLUDE_DIR \
	PL_LIB \
	J2SDK_ROOT \
	BERKELEY_DB_DIR \
	BERKELEY_DB_LIB \
	SECONDO_READLINE_DIR \
	SECONDO_JPEG_DIR \
	SECONDO_FLEX_DIR \
	SECONDO_LIBXML2_DIR \
	LIBRARY_PATH \
	SECONDO_HAS_RECODE

# LIBRARY_PATH is deliberately not in this list: it is read by the compiler
# driver, and an exported-but-empty LIBRARY_PATH is one empty path element,
# which gcc reads as the current directory. It is exported below only when it
# actually has a value (macOS).
export SECONDO_DETECTED $(filter-out LIBRARY_PATH,$(SECONDO_DETECT_VARS))

ifneq ($(strip $(LIBRARY_PATH)),)
export LIBRARY_PATH
endif

# Targets are only defined when this file is the makefile being run, not when
# it is included: the first target of the first makefile read becomes the
# default goal, and defining one here would displace the "all" of every
# makefile that includes us.
ifeq ($(firstword $(MAKEFILE_LIST)),$(lastword $(MAKEFILE_LIST)))

.PHONY: print-vars
print-vars:
	@$(foreach v,$(SECONDO_DETECT_VARS),printf '%s=%s\n' '$(v)' '$($(v))';)

# One-line summary plus warnings, exiting non-zero if anything is missing.
# The packaging runs this before "make" so that a missing dependency fails the
# build with a readable message, rather than producing a kernel with silently
# disabled features. The tests are shell rather than $(if ...) because make
# would split each message into one word per echo.
.PHONY: check-env
check-env:
	@printf 'secondo env: platform %s | swipl %s | jdk %s | bdb %s\n' \
	  '$(SECONDO_PLATFORM)' '$(if $(SWI_HOME_DIR),$(SWI_HOME_DIR),none)' \
	  '$(if $(J2SDK_ROOT),$(J2SDK_ROOT),MISSING)' \
	  '$(if $(BERKELEY_DB_DIR),$(BERKELEY_DB_DIR),MISSING)'
	@rc=0; \
	[ -n '$(SWI_HOME_DIR)' ] || { \
	  echo '  ! swipl not found -> optimizer disabled (install swi-prolog, or set SECONDO_SWIPL)'; rc=1; }; \
	[ -x '$(J2SDK_ROOT)/bin/javac' ] || { \
	  echo '  ! JDK not found -> Java GUI will not build (set J2SDK_ROOT)'; rc=1; }; \
	[ -f '$(BERKELEY_DB_DIR)/include/db_cxx.h' ] || { \
	  echo '  ! db_cxx.h not under $(BERKELEY_DB_DIR) (set BERKELEY_DB_DIR)'; rc=1; }; \
	exit $$rc

endif