configure

#!/usr/bin/tclsh

#
# SRT - Secure, Reliable, Transport
# Copyright (c) 2018 Haivision Systems Inc.
#
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
#

# This is a general-purpose configure script, which is a user-friendly
# wrapper to call the "cmake" command.

# There are two options that are handled specifically:
#
# --help: show the list of official options
# --prefix: alias to --cmake-install-prefix

# The processing done automatically on all options by default is:
# Every option like:
#    --long-c++-option
#    --cmake-special-option=ON
# Turns into:
#    -DLONG_CXX_OPTION=1
#    -DCMAKE_SPECIAL_OPTION=ON
#
# In the configuration file, "configure-data.tcl", you can add
# special processing for options and define explicit options
# in the "::options" dictionary. Explicit options (in contrast
# to "blind" options) have additional properties:
#
# - only those options are mentioned with --help
# - you can pass a value for this option without = character
# - you can specify --disable-option instead of --enable-option=0
#
# In "configure-data.tcl", beside ::options, you can define "preprocess" and
# "postprocess" procedures. In "preprocess", use ::optval array to modify the
# list of options to be processed further. Additionally in "postprocess"
# procedure you can influence directly the options for "cmake" command in
# ::cmakeopt variable (modifying ::optval in "postprocess" is useless).

# The idea is that CMakeLists.txt contains things that are highly
# customizable, but no system or option autodetection AWA "sensible
# defaults" are provided. This is done by this script.


set here [file dirname $argv0]

set options ""
set toolchain_changers ""

source $here/configure-data.tcl

# Update alias with default alias
dict set alias --prefix --cmake-install-prefix=

proc resolve opt {
	set type arg
	set pos [string first $opt =]
	if { $pos == -1 } {
		set type bool
		set mark ""
	} else {
		set type arg
		set mark [string range $opt $pos+1 end]
		set opt [string range $opt 0 $pos-1]
	}
	set var [string toupper [string map {- _ + x} $opt]]
	return [list --$opt $var $type $mark]
}

# Check if a --disable option has its --enable counterpart. If so,
# then just invert the option.
proc resolve_disablers {} {
	set enablers ""
	set optkeys_len [llength $::optkeys]
	for {set pos 0} {$pos < $optkeys_len} {incr pos} {
		set opt [lindex $::optkeys $pos]
		if { [string match --disable-* $opt] } {
			set inverted enable-[string range $opt 10 end]
			if { $inverted in [dict keys $::options] } {
				lset ::optkeys $pos --$inverted
				set val $::optval($opt)
				unset ::optval($opt)
				if { $val == "" || ![string is boolean $val] } {
					set ::optval(--$inverted) 0
				} else {
					set ::optval(--$inverted) [expr {!$val}]
				}

				puts "NOTE: $opt changed into --$inverted=$::optval(--$inverted)"
			}
		}
	}
}

foreach {o desc} $options {
	lassign [resolve $o] optname optvar opttype optmark
	set opt($optname) [list $optvar $opttype $optmark]
	set info($optname) $desc
}


if { $argv == "--help" } {
	puts stderr "Usage: ./configure \[options\]"
	puts stderr "OPTIONS:"
	foreach o [lsort [array names opt]] {
		lassign $opt($o) unu type mark
		set imark ""
		if { $mark != "" } {
			set imark "=$mark"
		}
		puts stderr "\t$o$imark - $info($o)"
	}

	puts stderr "NOTE1: Option list may be incomplete. Refer to variables in CMakeLists.txt"
	puts stderr "NOTE2: Non-internal options turn e.g. --enable-c++11 into cmake -DENABLE_CXX11=1"
	puts stderr "NOTE3: You can use --disable-x instead of --enable-x=0 for the above options."
	
	exit 1
}

if { [info proc init] != "" } {
	init
}

#parray opt

set saveopt ""
set optkeys ""

set dryrun 0
set type ""

foreach a $argv {
	if { [info exists val] } { unset val }

	if { $saveopt != "" } {
		set optval($saveopt) $a
		set saveopt ""
		continue
	}

	if { [string range $a 0 1] != "--" } {
		error "Unexpected argument '$a'. Options must start with --"
	}

	if { $a == "--dryrun" } {
		set dryrun 1
		continue
	}

	set type ""

	if { [string first = $a] != -1 } {
		lassign [split $a =] a val
	}

	if { [dict exists $::alias $a] } {
		set aname [dict get $::alias $a]
		if { [string first = $aname] != -1 } {
			lassign [split $aname =] a aval
			set type arg
		}
	}

	if { ![info exists opt($a)] } {
		#puts stderr "WARNING: Unknown option: $a"
		# But still, simply turn the option to assign-based use.
		lassign [resolve [string range $a 2 end]] oname var
		if { ![info exists val] && $type == "" } {
			set type bool
		}
	} else {
		lassign $opt($a) var type
	}

	if { $type == "bool" } {
		if { ![info exists val] } {
			set val 1
		}
		set optval($a) $val
	} elseif { [info exists val] } {
		set optval($a) $val
	} else {
		set saveopt $a
	}

	lappend optkeys $a
}

if { $saveopt != "" } {
	error "Extra unhandled argument: $saveopt"
}

set cmakeopt ""

resolve_disablers

if { [info proc preprocess] != "" } {
	preprocess
}

# Check if there were new values added not added to optkeys
foreach a [array names optval] {
	if { $a ni $optkeys } {
		lappend optkeys $a
	}
}


foreach a $optkeys {

	if { ![info exists optval($a)] } {
		continue  ;# user action might have removed it.
	}

	if { ![info exists opt($a)] } {
		#puts stderr "WARNING: Unknown option: $a"
		# But still, simply turn the option to assign-based use.
		lassign [resolve [string range $a 2 end]] oname var
		if { ![info exists val] && $type == "" } {
			set type bool
		}
	} else {
		lassign $opt($a) var type
	}

	set val $optval($a)
	lappend cmakeopt "-D$var=$val"
}


if { [info proc postprocess] != "" } {
	postprocess
}

#puts "VARSPEC: $cmakeopt"

set cmd [list cmake $here {*}$cmakeopt]
puts "Running: $cmd"
if { !$dryrun} {
	if { [catch {exec 2>@stderr >@stdout {*}$cmd} result] } {
		puts "CONFIGURE: cmake reported error: $result"
	}
} else {
	puts "(not really - dry run)"
}