[devhelp/wip/meson: 3/3] build: Add a configure script

[Iñigo Martínez <inigomartinez src gnome org>]

commit e108bc50319fbddcdfd84c54adff8b68390ad079
Author: Iñigo Martínez <inigomartinez gmail com>
Date:   Wed Nov 15 16:44:45 2017 +0100

    build: Add a configure script
    
    This configure script eases the transition from people who are
    familiar to autotools and also it is useful for those applications
    that may use it.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=783819

 configure |  166 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 166 insertions(+), 0 deletions(-)
---
diff --git a/configure b/configure
new file mode 100755
index 0000000..8912cb3
--- /dev/null
+++ b/configure
@@ -0,0 +1,166 @@
+#!/bin/bash
+# configure script adapter for Meson
+# Based on build-api: https://github.com/cgwalters/build-api
+# Copyright 2010, 2011, 2013 Colin Walters <walters verbum org>
+# Copyright 2016, 2017 Emmanuele Bassi
+# Copyright 2017 Iñigo Martínez <inigomartinez gmail com>
+# Licensed under the new-BSD license (http://www.opensource.org/licenses/bsd-license.php)
+
+# Build API variables:
+
+# Little helper function for reading args from the commandline.
+# it automatically handles -a b and -a=b variants, and returns 1 if
+# we need to shift $3.
+read_arg() {
+    # $1 = arg name
+    # $2 = arg value
+    # $3 = arg parameter
+    local rematch='^[^=]*=(.*)$'
+    if [[ $2 =~ $rematch ]]; then
+        read "$1" <<< "${BASH_REMATCH[1]}"
+    else
+        read "$1" <<< "$3"
+        # There is no way to shift our callers args, so
+        # return 1 to indicate they should do it instead.
+        return 1
+    fi
+}
+
+sanitycheck() {
+    # $1 = arg name
+    # $1 = arg command
+    # $2 = arg alternates
+    local cmd=$( which $2 2>/dev/null )
+
+    if [ -x "$cmd" ]; then
+        read "$1" <<< "$cmd"
+        return 0
+    fi
+
+    test -z $3 || {
+        for alt in $3; do
+            cmd=$( which $alt 2>/dev/null )
+
+            if [ -x "$cmd" ]; then
+                read "$1" <<< "$cmd"
+                return 0
+            fi
+        done
+    }
+
+    echo -e "\e[1;31mERROR\e[0m: Command '$2' not found"
+    exit 1
+}
+
+checkoption() {
+    # $1 = arg
+    option="${1#*--}"
+    action="${option%%-*}"
+    name="${option#*-}"
+    if [ ${default_options[$name]+_} ]; then
+        case "$action" in
+            enable) meson_options[$name]=true;;
+            disable) meson_options[$name]=false;;
+            *) echo -e "\e[1;33mINFO\e[0m: Ignoring unknown action '$action'";;
+        esac
+    else
+        echo -e "\e[1;33mINFO\e[0m: Ignoring unknown option '$option'"
+    fi
+}
+
+echooption() {
+    # $1 = option
+    if [ ${meson_options[$1]+_} ]; then
+        echo ${meson_options[$1]}
+    elif [ ${default_options[$1]+_} ]; then
+        echo ${default_options[$1]}
+    fi
+}
+
+sanitycheck MESON 'meson'
+sanitycheck MESONTEST 'mesontest'
+sanitycheck NINJA 'ninja' 'ninja-build'
+
+declare -A default_options=(
+    ['gtk-doc']=true
+    ['introspection']=true
+)
+
+declare -A meson_options
+
+while (($# > 0)); do
+    case "${1%%=*}" in
+        --prefix) read_arg prefix "$@" || shift;;
+        --bindir) read_arg bindir "$@" || shift;;
+        --sbindir) read_arg sbindir "$@" || shift;;
+        --libexecdir) read_arg libexecdir "$@" || shift;;
+        --datarootdir) read_arg datarootdir "$@" || shift;;
+        --datadir) read_arg datadir "$@" || shift;;
+        --sysconfdir) read_arg sysconfdir "$@" || shift;;
+        --libdir) read_arg libdir "$@" || shift;;
+        --mandir) read_arg mandir "$@" || shift;;
+        --includedir) read_arg includedir "$@" || shift;;
+        *) checkoption $1;;
+    esac
+    shift
+done
+
+# Defaults
+test -z ${prefix} && prefix="/usr/local"
+test -z ${bindir} && bindir=${prefix}/bin
+test -z ${sbindir} && sbindir=${prefix}/sbin
+test -z ${libexecdir} && libexecdir=${prefix}/bin
+test -z ${datarootdir} && datarootdir=${prefix}/share
+test -z ${datadir} && datadir=${datarootdir}
+test -z ${sysconfdir} && sysconfdir=${prefix}/etc
+test -z ${libdir} && libdir=${prefix}/lib
+test -z ${mandir} && mandir=${prefix}/share/man
+test -z ${includedir} && includedir=${prefix}/include
+
+# The source directory is the location of this file
+srcdir=$(dirname $0)
+
+# The build directory is the current location
+builddir=`pwd`
+
+# If we're calling this file from the source directory then
+# we automatically create a build directory and ensure that
+# both Meson and Ninja invocations are relative to that
+# location
+if [[ -f "${builddir}/meson.build" ]]; then
+    mkdir -p _build
+    builddir="${builddir}/_build"
+    NINJA_OPT="-C ${builddir}"
+fi
+
+# Wrapper Makefile for Ninja
+cat > Makefile <<END
+# Generated by configure; do not edit
+
+all:
+       CC="\$(CC)" CXX="\$(CXX)" ${NINJA} ${NINJA_OPT}
+
+install:
+       DESTDIR="\$(DESTDIR)" ${NINJA} ${NINJA_OPT} install
+
+check:
+       ${MESONTEST} ${NINJA_OPT}
+END
+
+cmd_options=""
+for key in "${!meson_options[@]}"; do
+    cmd_options="$cmd_options -D${key/\-/_}=${meson_options[$key]}"
+done
+
+exec ${MESON} \
+    --prefix=${prefix} \
+    --libdir=${libdir} \
+    --libexecdir=${libexecdir} \
+    --datadir=${datadir} \
+    --sysconfdir=${sysconfdir} \
+    --bindir=${bindir} \
+    --includedir=${includedir} \
+    --mandir=${mandir} \
+    ${cmd_options} \
+    ${builddir} \
+    ${srcdir}