configure

#!/bin/sh
# Anticonf (tm) script by Jeroen Ooms (2022)
# This script will query 'pkg-config' for the required cflags and ldflags.
# On MacOS and Linux, if libgit2 is not found or too old, we try to downoad
# a portable static build and use that instead.

# Library settings
PKG_CONFIG_NAME="libgit2"
PKG_DEB_NAME="libgit2-dev"
PKG_RPM_NAME="libgit2-devel"
PKG_BREW_NAME="libgit2"
PKG_TEST_HEADER="<git2.h>"
PKG_TEST_FILE="tools/version.c"
PKG_LIBS="-lgit2"
PKG_CFLAGS=""

# Test for production platforms
if test -f "/etc/os-release" && grep -Fq Ubuntu "/etc/os-release"; then
PREFER_STATIC_LIBGIT2=1
fi

# Use pkg-config if available
pkg-config ${PKG_CONFIG_NAME} --atleast-version=0.19 2>/dev/null
if [ $? -eq 0 ]; then
  PKGCONFIG_CFLAGS=`pkg-config --cflags --silence-errors ${PKG_CONFIG_NAME}`
  PKGCONFIG_LIBS=`pkg-config --libs ${PKG_CONFIG_NAME}`

  # Test if the local system version of libgit2 is recent enough
  if [ -z "$PREFER_STATIC_LIBGIT2" ]; then
    pkg-config ${PKG_CONFIG_NAME} --atleast-version=1.0 && USE_SYSTEM_LIBGIT2=1
  fi
fi

# On Linux distros with old libgit2, try downloading our static build.
PLATFORM=`uname -sm`
if [ -z "$USE_SYSTEM_LIBGIT2" ] && [ "$PLATFORM" = "Linux x86_64" ]; then
  ${R_HOME}/bin/R -s -e 'curl::curl_download("https://r-lib.github.io/gert/get-libgit2-linux.sh","get-libgit2-linux.sh")' || true
  if [ -f "get-libgit2-linux.sh" ]; then
  . ./get-libgit2-linux.sh
  fi
fi

# Check for custom locations
if [ "$INCLUDE_DIR" ] || [ "$LIB_DIR" ]; then
  echo "Found INCLUDE_DIR and/or LIB_DIR!"
  PKG_CFLAGS="-I$INCLUDE_DIR $PKG_CFLAGS"
  PKG_LIBS="-L$LIB_DIR $PKG_LIBS"
elif [ "$HAVE_STATIC_LIBGIT2" ]; then
  echo "Using static libgit2 for $PLATFORM"
elif [ "$PKGCONFIG_CFLAGS" ] || [ "$PKGCONFIG_LIBS" ]; then
  echo "Found pkg-config cflags and libs!"
  PKG_CFLAGS=${PKGCONFIG_CFLAGS}
  PKG_LIBS=${PKGCONFIG_LIBS}
elif [ `uname` = "Darwin" ]; then
  test ! "$CI" && brew --version 2>/dev/null
  if [ $? -eq 0 ]; then
    BREWDIR=`brew --prefix`
    PKG_CFLAGS="-I$BREWDIR/opt/$PKG_BREW_NAME/include"
    PKG_LIBS="-L$BREWDIR/opt/$PKG_BREW_NAME/lib $PKG_LIBS"
  else
    curl -sfL "https://autobrew.github.io/scripts/$PKG_BREW_NAME" > autobrew
    . ./autobrew
  fi
fi

# Find compiler
CC=`${R_HOME}/bin/R CMD config CC`
CFLAGS=`${R_HOME}/bin/R CMD config CFLAGS`
CPPFLAGS=`${R_HOME}/bin/R CMD config CPPFLAGS`

# For debugging
echo "Using PKG_CFLAGS=$PKG_CFLAGS"
echo "Using PKG_LIBS=$PKG_LIBS"

# Test configuration
echo "#include $PKG_TEST_HEADER" | ${CC} ${CPPFLAGS} ${PKG_CFLAGS} ${CFLAGS} -E -xc - >/dev/null 2>configure.log

# Customize the error
if [ $? -ne 0 ]; then
  echo "----------------------------- ANTICONF -------------------------------"
  echo "Configuration failed to find $PKG_CONFIG_NAME library. Try installing:"
  echo " * brew: $PKG_BREW_NAME (MacOS)"
  echo " * deb: $PKG_DEB_NAME (Debian, Ubuntu, etc)"
  echo " * rpm: $PKG_RPM_NAME (Fedora, CentOS, RHEL)"
  echo "If $PKG_CONFIG_NAME is already installed, check that 'pkg-config' is in your"
  echo "PATH and PKG_CONFIG_PATH contains a $PKG_CONFIG_NAME.pc file. If pkg-config"
  echo "is unavailable you can set INCLUDE_DIR and LIB_DIR manually via:"
  echo "R CMD INSTALL --configure-vars='INCLUDE_DIR=... LIB_DIR=...'"
  echo "-------------------------- [ERROR MESSAGE] ---------------------------"
  cat configure.log
  echo "----------------------------------------------------------------------"
  exit 1
fi

# Write to Makevars
sed -e "s|@cflags@|$PKG_CFLAGS|" -e "s|@libs@|$PKG_LIBS|" src/Makevars.in > src/Makevars

# Success
echo "Configuration OK!"
exit 0