From 62aa4d4bcfb0e5c77907b3f61964adfca7fbc4f2 Mon Sep 17 00:00:00 2001
From: Greg Steuck <greg@nest.cx>
Date: Sun, 13 Sep 2020 17:04:03 -0700
Subject: [PATCH] Add cabal.port.mk to more easily build haskell ports

---
 devel/cabal/cabal.port.mk | 155 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 155 insertions(+)
 create mode 100644 devel/cabal/cabal.port.mk

diff --git a/devel/cabal/cabal.port.mk b/devel/cabal/cabal.port.mk
new file mode 100644
index 000000000000..d10fe6ddb885
--- /dev/null
+++ b/devel/cabal/cabal.port.mk
@@ -0,0 +1,155 @@
+# $OpenBSD$
+
+# Module for building Haskell programs with cabal-install.
+# Inspired by FreeBSD cabal.mk by Gleb Popov.
+
+# Input variables:
+#
+#  MODCABAL_STEM - the name of the package on hackage.
+#  MODCABAL_VERSION  - the version of the package.
+#  MODCABAL_MANIFEST - hackage dependencies required by this package, tripples
+#    of space separate <package> <version> <revision>. Typically generated
+#    with cabal-bundler program from cabal-extras. The patch pending review
+#    https://github.com/phadej/cabal-extras/pull/32
+#  MODCABAL_DATA_DIR - data-dir from .cabal file (if the port needs the data)
+#    https://cabal.readthedocs.io/en/latest/cabal-package.html#pkg-field-data-dir
+#  MODCABAL_REVISION - Numeric revision of .cabal file on hackage if one is
+#    needed on top of .cabal file contained in the .tar.gz file.
+#  MODCABAL_BUILD_ARGS - passed to cabal v2-build, e.g. make MODCABAL_BUILD_ARGS=-v
+#    is a nice debugging aid.
+#  MODCABAL_FLAGS - passed to --flags= of cabal v2-build. Seemingly superflous given
+#    MODCABAL_BUILD_ARGS, but it is useful to keep this value separate as it
+#    is used to generate the build plan and will be available without parsing.
+#  MODCABAL_EXECUTABLES - Executable target in .cabal file, by default uses
+#    the hackage package name.
+#    https://cabal.readthedocs.io/en/latest/cabal-package.html#executables
+#
+# Available output variables:
+#
+#  MODCABAL_BUILT_EXECUTABLE_${_exe} is built for each of MODCABAL_EXECUTABLES.
+#    These are available for `make test` after `make build` phase.
+#
+# Special files:
+#   files/cabal.project is used automatically.
+
+ONLY_FOR_ARCHS =	i386 amd64
+
+BUILD_DEPENDS +=	devel/cabal \
+			lang/ghc
+
+# Takes over :9 site for hackage. The day when we have a port using
+# both Go/Rust and Hackage we'll have to resolve their common
+# insistance on grabbing :9.
+MASTER_SITES9 =		https://hackage.haskell.org/package/
+
+DIST_SUBDIR ?= 		hackage
+
+# The .cabal files are explicitly copied over the ones extracted from
+# archives by the normal extraction rules.
+EXTRACT_CASES += *.cabal) ;;
+
+DISTNAME ?=		${MODCABAL_STEM}-${MODCABAL_VERSION}
+HOMEPAGE ?=		${MASTER_SITES9}${MODCABAL_STEM}
+MASTER_SITES ?=		${MASTER_SITES9}${DISTNAME}/
+DISTFILES ?=		${DISTNAME}.tar.gz
+SUBST_VARS +=		MODCABAL_STEM MODCABAL_VERSION PKGNAME
+
+# Oftentime our port name and the executable name coincide.
+MODCABAL_EXECUTABLES ?=	${MODCABAL_STEM}
+
+# Cabal won't download anything from hackage if config file exists.
+MODCABAL_post-extract = \
+	mkdir -p ${WRKDIR}/.cabal \
+	&& touch ${WRKDIR}/.cabal/config
+
+# Some packages need an updated .cabal file from hackage to overwrite
+# the one in the tar ball.
+.if defined(MODCABAL_REVISION)
+DISTFILES += ${DISTNAME}_${MODCABAL_REVISION}{revision/${MODCABAL_REVISION}}.cabal
+MODCABAL_post-extract += \
+	&& cp ${FULLDISTDIR}/${DISTNAME}_${MODCABAL_REVISION}.cabal \
+		${WRKSRC}/${MODCABAL_STEM}.cabal
+.endif
+
+# The dependent sources get downloaded from hackage.
+.for _package _version _revision in ${MODCABAL_MANIFEST}
+DISTFILES += {${_package}-${_version}/}${_package}-${_version}.tar.gz:9
+.  if ${_revision} > 0
+DISTFILES += ${_package}-${_version}_${_revision}{${_package}-${_version}/revision/${_revision}}.cabal:9
+MODCABAL_post-extract += \
+	&& cp ${FULLDISTDIR}/${_package}-${_version}_${_revision}.cabal \
+		${WRKDIR}/${_package}-${_version}/${_package}.cabal
+.  endif
+# References all the locally available dependencies.  Ideally these
+# should be command line options, tracking issue:
+# https://github.com/haskell/cabal/issues/3585
+MODCABAL_post-extract += \
+	&& echo "packages: ${WRKDIR}/${_package}-${_version}/${_package}.cabal" >> ${WRKSRC}/cabal.project.local
+.endfor  # MODCABAL_MANIFEST
+
+# Automatically copies the cabal.project file if any.
+MODCABAL_post-extract += \
+	&& (test -f ${FILESDIR}/cabal.project \
+	    && cp -v ${FILESDIR}/cabal.project ${WRKSRC}; true)
+
+# Invokes cabal with HOME set up to use .cabal directory created in
+# post-extract.
+_MODCABAL_CABAL = ${SETENV} ${MAKE_ENV} HOME=${WRKDIR} ${LOCALBASE}/bin/cabal
+
+# Building a cabal package is merely an invocation of cabal v2-build.
+_MODCABAL_BUILD_TARGET = \
+	cd ${WRKBUILD} \
+	&& ${_MODCABAL_CABAL} v2-build --offline --disable-benchmarks --disable-tests \
+		-w ${LOCALBASE}/bin/ghc \
+		-j${MAKE_JOBS} \
+		--flags="${MODCABAL_FLAGS}" ${MODCABAL_BUILD_ARGS} \
+		${MODCABAL_EXECUTABLES:C/^/exe:&/}
+
+# Install fragment starts this way for uniformity of incremental construction.
+_MODCABAL_INSTALL_TARGET = true
+
+# Prepares wrapping fragments that only need to be set up once and
+# reused across potentially multiple installed executables.
+.if defined(MODCABAL_DATA_DIR)
+_MODCABAL_LIBEXEC = libexec/cabal
+_MODCABAL_INSTALL_TARGET += \
+	&& mkdir -p ${PREFIX}/${_MODCABAL_LIBEXEC}
+
+_MODCABAL_INSTALL_TARGET +=  \
+	&& ${INSTALL_DATA_DIR} ${WRKSRC}/${MODCABAL_DATA_DIR} ${PREFIX}/share/${DISTNAME} \
+	&& cd ${WRKSRC}/${MODCABAL_DATA_DIR} && umask 022 && pax -rw . ${PREFIX}/share/${DISTNAME}
+.endif
+
+# Appends installation fragments for each executable.
+.for _exe in ${MODCABAL_EXECUTABLES}
+# Exports the path to the executable for testing. The location is
+# somewhat hard to predict in advance, thus it is determined at runtime.
+MODCABAL_BUILT_EXECUTABLE_${_exe} = $$(find ${WRKSRC}/dist-newstyle -name ${_exe} -type f -perm -a+x)
+.  if defined(MODCABAL_DATA_DIR)
+# Installs the ELF binary into an auxiliary location and wraps it into
+# a script which sets up the environment to point at the data-dir
+# files if any.
+_MODCABAL_INSTALL_TARGET += \
+	&& ${INSTALL_PROGRAM} \
+		${MODCABAL_BUILT_EXECUTABLE_${_exe}} \
+		${PREFIX}/${_MODCABAL_LIBEXEC}/${_exe} \
+	&& echo '\#!/bin/sh' > ${PREFIX}/bin/${_exe} \
+	&& echo 'export ${_exe}_datadir=${LOCALBASE}/share/${DISTNAME}' >> ${PREFIX}/bin/${_exe} \
+	&& echo 'exec ${LOCALBASE}/${_MODCABAL_LIBEXEC}/${_exe} "$$@"' >> ${PREFIX}/bin/${_exe} \
+	&& chmod +x ${STAGEDIR}${PREFIX}/bin/${_exe}
+.  else
+# Skips the launcher script indirection when MODCABAL_DATA_DIR is empty.
+_MODCABAL_INSTALL_TARGET += \
+	&& ${INSTALL_PROGRAM} ${MODCABAL_BUILT_EXECUTABLE_${_exe}} ${PREFIX}/bin
+.  endif
+.endfor
+
+.if !target(do-build)
+do-build:
+	@${_MODCABAL_BUILD_TARGET}
+.endif
+
+.if !target(do-install)
+do-install:
+	@${_MODCABAL_INSTALL_TARGET}
+.endif