From 3e6acd43fdde938044cf30dcab69dbe37b7a0e72 Mon Sep 17 00:00:00 2001
From: Keno Fischer <keno@juliacomputing.com>
Date: Mon, 5 Oct 2020 01:51:37 -0400
Subject: [PATCH] Make bash wrapper relocatable

By having the build system put in a relative path rather
than an absolute path. Unfortunately, make does not support
computing relative paths manually, so a small bash script is
needed that will do this for us.
---
 tcltk/Makefile        | 11 ++++++++---
 tcltk/ext2sim.sh.in   |  8 +++++++-
 tcltk/ext2spice.sh.in |  8 +++++++-
 tcltk/magic.sh.in     | 18 ++++++++++++------
 tcltk/relpath.sh      | 40 ++++++++++++++++++++++++++++++++++++++++
 5 files changed, 74 insertions(+), 11 deletions(-)
 create mode 100755 tcltk/relpath.sh

diff --git a/tcltk/Makefile b/tcltk/Makefile
index f79924c9..c233daff 100644
--- a/tcltk/Makefile
+++ b/tcltk/Makefile
@@ -32,6 +32,11 @@ TCL_FILES = \
 	readspice.tcl \
 	magic.tcl
 
+TCL_DIR_REL_OR_ABS = $(shell ${MAGICDIR}/tcltk/relpath.sh "$(DESTDIR)${INSTALL_BINDIR}" ${TCLDIR})
+ifeq ($(TCL_DIR_REL_OR_ABS),)
+TCL_DIR_REL_OR_ABS = ${TCLDIR}
+endif
+
 BIN_FILES = \
 	$(DESTDIR)${INSTALL_BINDIR}/magic.sh \
 	$(DESTDIR)${INSTALL_BINDIR}/ext2spice.sh \
@@ -66,15 +71,15 @@ magic.tcl: magic.tcl.in ${MAGICDIR}/defs.mak ${MAGICDIR}/VERSION
 	    -e /SHDLIB_EXT/s%SHDLIB_EXT%${SHDLIB_EXT}%g magic.tcl.in > magic.tcl
 
 magic.sh: magic.sh.in ${MAGICDIR}/defs.mak
-	sed -e /TCL_DIR/s%TCL_DIR%${TCLDIR}%g \
+	sed -e /TCL_DIR_REL_OR_ABS/s%TCL_DIR_REL_OR_ABS%${TCL_DIR_REL_OR_ABS}%g \
 	    -e /TCLLIB_DIR/s%TCLLIB_DIR%${TCL_LIB_DIR}%g \
 	    -e /WISH_EXE/s%WISH_EXE%${WISH_EXE}%g magic.sh.in > magic.sh
 
 ext2spice.sh: ext2spice.sh.in ${MAGICDIR}/defs.mak
-	sed -e /TCL_DIR/s%TCL_DIR%${TCLDIR}%g ext2spice.sh.in > ext2spice.sh
+	sed -e /TCL_DIR_REL_OR_ABS/s%TCL_DIR_REL_OR_ABS%${TCL_DIR_REL_OR_ABS}%g ext2spice.sh.in > ext2spice.sh
 
 ext2sim.sh: ext2sim.sh.in ${MAGICDIR}/defs.mak
-	sed -e /TCL_DIR/s%TCL_DIR%${TCLDIR}%g ext2sim.sh.in > ext2sim.sh
+	sed -e /TCL_DIR_REL_OR_ABS/s%TCL_DIR_REL_OR_ABS%${TCL_DIR_REL_OR_ABS}%g ext2sim.sh.in > ext2sim.sh
 
 $(DESTDIR)${INSTALL_TCLDIR}/%: %
 	${RM} $(DESTDIR)${INSTALL_TCLDIR}/$*
diff --git a/tcltk/ext2sim.sh.in b/tcltk/ext2sim.sh.in
index 548657ae..1ac1aad1 100755
--- a/tcltk/ext2sim.sh.in
+++ b/tcltk/ext2sim.sh.in
@@ -14,8 +14,14 @@ for i in $@; do
       *) esargs="$esargs $i" ;;
    esac
 done
+TCL_REL_OR_ABS=TCL_DIR_REL_OR_ABS
+if [ "${TCL_REL_OR_ABS:0:1}" = "/" ]; then
+TCL_DIR=$TCL_REL_OR_ABS
+else
+TCL_DIR=$(dirname $(realpath ${BASH_SOURCE[0]}))/$TCL_REL_OR_ABS
+fi
 #
-eval TCL_DIR/magicdnull -dnull -noconsole -nowrapper $mgargs <<EOF
+eval ${TCL_DIR}/magicdnull -dnull -noconsole -nowrapper $mgargs <<EOF
 drc off
 box 0 0 0 0
 ext2sim $esargs
diff --git a/tcltk/ext2spice.sh.in b/tcltk/ext2spice.sh.in
index 037abae1..7682beea 100755
--- a/tcltk/ext2spice.sh.in
+++ b/tcltk/ext2spice.sh.in
@@ -14,8 +14,14 @@ for i in $@; do
       *) esargs="$esargs $i" ;;
    esac
 done
+TCL_REL_OR_ABS=TCL_DIR_REL_OR_ABS
+if [ "${TCL_REL_OR_ABS:0:1}" = "/" ]; then
+TCL_DIR=$TCL_REL_OR_ABS
+else
+TCL_DIR=$(dirname $(realpath ${BASH_SOURCE[0]}))/$TCL_REL_OR_ABS
+fi
 #
-eval TCL_DIR/magicdnull -dnull -noconsole -nowrapper $mgargs <<EOF
+eval ${TCL_DIR}/magicdnull -dnull -noconsole -nowrapper $mgargs <<EOF
 drc off
 box 0 0 0 0
 ext2spice $esargs
diff --git a/tcltk/magic.sh.in b/tcltk/magic.sh.in
index 1621150c..e3d8c7a0 100755
--- a/tcltk/magic.sh.in
+++ b/tcltk/magic.sh.in
@@ -11,6 +11,12 @@
 # Parse for the argument "-c[onsole]".  If it exists, run magic
 # with the TkCon console.  Strip this argument from the argument list.
 
+TCL_REL_OR_ABS=TCL_DIR_REL_OR_ABS
+if [ "${TCL_REL_OR_ABS:0:1}" = "/" ]; then
+TCL_DIR=$TCL_REL_OR_ABS
+else
+TCL_DIR=$(dirname $(realpath ${BASH_SOURCE[0]}))/$TCL_REL_OR_ABS
+fi
 TKCON=true
 DNULL=
 MAGIC_WISH=WISH_EXE
@@ -37,12 +43,12 @@ done
 if [ $TKCON ]; then
 
    if [ $DNULL ]; then
-      exec TCL_DIR/tkcon.tcl -eval "source TCL_DIR/console.tcl" \
-	   -slave "set argc $#; set argv [list $*]; source TCL_DIR/magic.tcl"
+      exec $TCL_DIR/tkcon.tcl -eval "source $TCL_DIR/console.tcl" \
+	   -slave "set argc $#; set argv [list $*]; source $TCL_DIR/magic.tcl"
    else
-      exec TCL_DIR/tkcon.tcl -eval "source TCL_DIR/console.tcl" \
+      exec $TCL_DIR/tkcon.tcl -eval "source $TCL_DIR/console.tcl" \
 	   -slave "package require Tk; set argc $#; set argv [list $arglist]; \
-	   source TCL_DIR/magic.tcl"
+	   source $TCL_DIR/magic.tcl"
    fi
 
 else
@@ -57,8 +63,8 @@ else
 # only, efficient for running in batch mode).
 #
    if [ $DNULL ]; then
-      exec TCL_DIR/magicdnull -nowrapper "$@"
+      exec $TCL_DIR/magicdnull -nowrapper "$@"
    else
-      exec TCL_DIR/magicexec -- "$@"
+      exec $TCL_DIR/magicexec -- "$@"
    fi
 fi
diff --git a/tcltk/relpath.sh b/tcltk/relpath.sh
new file mode 100755
index 00000000..abeac959
--- /dev/null
+++ b/tcltk/relpath.sh
@@ -0,0 +1,40 @@
+#!/bin/bash
+# From https://stackoverflow.com/questions/2564634/convert-absolute-path-into-relative-path-given-a-current-directory-using-bash
+# both $1 and $2 are absolute paths beginning with /
+# returns relative path to $2/$target from $1/$source
+source=$1
+target=$2
+
+common_part=$source # for now
+result="" # for now
+
+while [[ "${target#$common_part}" == "${target}" ]]; do
+    # no match, means that candidate common part is not correct
+    # go up one level (reduce common part)
+    common_part="$(dirname $common_part)"
+    # and record that we went back, with correct / handling
+    if [[ -z $result ]]; then
+        result=".."
+    else
+        result="../$result"
+    fi
+done
+
+if [[ $common_part == "/" ]]; then
+    # special case for root (no common path)
+    result="$result/"
+fi
+
+# since we now have identified the common part,
+# compute the non-common part
+forward_part="${target#$common_part}"
+
+# and now stick all parts together
+if [[ -n $result ]] && [[ -n $forward_part ]]; then
+    result="$result$forward_part"
+elif [[ -n $forward_part ]]; then
+    # extra slash removal
+    result="${forward_part:1}"
+fi
+
+echo $result