Re: Building Emacs from a new MinGW environment

[Dani Moncayo <dmoncayo@gmail.com>]

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>> > In a nutshell, srcdir is now guaranteed to be in /d/foo/bar format,
>> > and should be edited into d:/foo/bar when it is placed in
>> > src/epaths.h.  The job is to remove anything from top-level
>> > Makefile.in that is required for file names in format other than
>> > /d/foo/bar, and still allow using %emacs_dir% in
>> > '--enable-locallisppath=PATH' option to configure.  So I think
>> > msys_to_w32 should stay intact, but msys_lisppath_to_w32 could be
>> > simplified.
>>
>> A more ambitious goal, IMO, would be to understand what is the problem
>> with doing every conversion of MSYS paths to native w32 format with
>> "pwd -W", so that the pattern-matching technique could be entirely
>> replaced with that simpler and more elegant one.
>
> That's a possibility, but note that "pwd -W" requires that you cd into
> the directory first, which might be a problem in some rare cases.
>
> Also msys_lisppath_to_w32 works on PATH-style directory lists, not on
> single directories, and some of those directories might not exist, or
> include %emacs_dir%, which will cause pwd to fail.
>
> If these difficulties can be overcome, I have nothing against using
> "pwd -W".

I'm attaching a patch that works for me, and I think fulfills the
above requirements.

It makes _all_ translations of paths to native MS-Windows format using
the "pwd -W" feature of the MSYS shell, which I think is the only
reliable way of doing such translations.

-- 
Dani Moncayo

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diff --git a/Makefile.in b/Makefile.in
index 984dcea..ed3aa8b 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -317,22 +317,9 @@ epaths-force: FRC
 	  -e 's;\(#.*PATH_DOC\).*$$;\1 "${etcdocdir}";') &&		\
 	${srcdir}/build-aux/move-if-change epaths.h.$$$$ src/epaths.h
 
-# Convert MSYS-style /x/foo or Windows-style x:\foo file names
-# into x:/foo that Windows can grok.
-msys_to_w32=sed -e 's,\\\\,/,g' -e 's,^/\([A-Za-z]\)/,\1:/,'
-
-# Transform directory search path and its components.  Original can
-# be MSYS or Windows style.  Set path separator to ";", directory
-# separator to "/" and transform MSYS-style "/c/" to "c:/".
-# Remove empty path components and escape semicolons.
-msys_lisppath_to_w32=sed -e 's,\\\\,/,g' 			\
-	-e 's,\(^\|[:;]\)\([A-Za-z]\):/,\1/\2/,g'		\
-	-e 's/:/;/g' -e 's,\(^\|;\)/\([A-Za-z]\)/,\1\2:/,g'	\
-	-e 's/;\+/;/g' -e 's/^;//' -e 's/;$$//' -e 's/;/\\\\;/g'
-
-# Replace "${prefix}" with '%emacs_dir%' (which expands to install
+# Replace "${w32prefix}" with '%emacs_dir%' (which expands to install
 # directory at runtime).
-msys_prefix_subst=sed -e 's!\(^\|;\)'"$${prefixpattern}"'\([;/]\|$$\)!\1%emacs_dir%\2!g'
+msys_w32prefix_subst=sed -e 's!\(^\|;\)'"$${w32prefixpattern}"'\([;/]\|$$\)!\1%emacs_dir%\2!g'
 
 # Quote Sed special characters (except backslash and newline) with
 # a double backslash.
@@ -340,22 +327,21 @@ msys_sed_sh_escape=sed -e 's/[];$$*.^[]/\\\\&/g'
 
 # The w32 build needs a slightly different editing, and it uses
 # nt/epaths.nt as the template.
+#
 # Use the value of ${locallisppath} supplied by `configure',
 # to support the --enable-locallisppath argument.
 #
-# When building with MinGW inside the MSYS tree, 'pwd' produces directories
-# relative to the root of the MSYS tree, e.g. '/home/user/foo' instead of
-# '/d/MSYS/home/user/foo'.  If such a value of srcdir is written to
-# src/epaths.h, that causes temacs to fail, because, being a MinGW
-# program that knows nothing of MSYS root substitution, it cannot find
-# the data directory.  "pwd -W" produces Windows-style 'd:/foo/bar'
-# absolute directory names, so we use it here to countermand that lossage.
+# In this case, the paths written to 'src/epaths.h' must be in native
+# MS-Windows format (e.g. 'c:/foo/bar'), because temacs is a MinGW
+# program that doesn't support MSYS-style paths (e.g. '/c/foo/bar' or
+# '/foo/bar').
 epaths-force-w32: FRC
-	@(w32srcdir=`cd "${srcdir}"; pwd -W | sed -e 's,^\([A-Za-z]\):,/\1,' | ${msys_to_w32}` ; 	\
-	  prefixpattern=`echo '${prefix}' | ${msys_to_w32} | ${msys_sed_sh_escape}` ; \
-	  locallisppath=`echo '${locallisppath}' | ${msys_lisppath_to_w32} | ${msys_prefix_subst}` ; \
+	@(w32srcdir=`${srcdir}/build-aux/msys-to-w32 "${srcdir}"`; \
+	  w32prefix=`${srcdir}/build-aux/msys-to-w32 "${prefix}" N`; \
+	  w32prefixpattern=`echo "${w32prefix}" | ${msys_sed_sh_escape}` ; \
+	  w32locallisppath=`${srcdir}/build-aux/msys-to-w32 "${locallisppath}" N ":" "\\;" | ${msys_w32prefix_subst}` ; \
 	  sed < ${srcdir}/nt/epaths.nt > epaths.h.$$$$		\
-	  -e 's;\(#.*PATH_SITELOADSEARCH\).*$$;\1 "'"$${locallisppath}"'";' \
+	  -e 's;\(#.*PATH_SITELOADSEARCH\).*$$;\1 "'"$${w32locallisppath}"'";' \
 	  -e '/^.*#/s/@VER@/${version}/g' 			\
 	  -e '/^.*#/s/@CFG@/${configuration}/g' 		\
 	  -e "/^.*#/s|@SRC@|$${w32srcdir}|g") &&		\
diff --git a/build-aux/msys-to-w32 b/build-aux/msys-to-w32
new file mode 100644
index 0000000..f8ae2d4
--- /dev/null
+++ b/build-aux/msys-to-w32
@@ -0,0 +1,188 @@
+#!/bin/sh
+# Take a list of MSYS-compatible paths and convert them to native
+# MS-Windows format.
+# Status is zero if successful, nonzero otherwise.
+
+VERSION='2013-11-09 10:48'; # UTC
+# The definition above must lie within the first 8 lines in order
+# for the Emacs time-stamp write hook (at end) to update it.
+# If you change this file with Emacs, please let the write hook
+# do its job.  Otherwise, update this string manually.
+
+# Copyright (C) 2002-2013 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+usage="usage: $0 PATHLIST [MUSTEXIST] [SEPARATOR [SEPARATOR2]]"
+
+help="$usage
+  or:  $0 OPTION
+
+Convert MSYS-compatible paths to MS-Windows native format.
+
+PATHLIST should be a list of paths separated by SEPARATOR.  This list
+will be written to the standard output after performing the following
+transformations:
+1. Empty paths will be discarded.
+2. Backslashes will be replaced by forward slashed.
+3. Two consecutive slashes will be replaced by a single one.
+4. Each path will be translated to Windows-native format, using
+   forward slashes (e.g. 'c:/foo/bar').  This translated path will
+   never end with a slash.
+5. Ocurrences of SEPARATOR2 withing the paths will be escaped with
+   backslashes.
+6. Different paths will be separated with SEPARATOR2.
+
+If MUSTEXIST is 'Y' (or not supplied), then each path in PATHLIST must
+exists.
+
+If SEPARATOR is not supplied, PATHLIST will be regarded as a single
+path.
+
+If SEPARATOR2 is not supplied, it will take the same value as
+SEPARATOR.
+
+Options:
+  --help     display this help and exit
+  --version  output version information and exit
+
+Report bugs to <bug-gnu-emacs@gnu.org>."
+
+version=`expr "$VERSION" : '\([^ ]*\)'`
+version="msys-to-w32 $version
+Copyright (C) 2011 Free Software Foundation, Inc.
+License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
+This is free software: you are free to change and redistribute it.
+There is NO WARRANTY, to the extent permitted by law."
+
+for arg
+do
+  case $arg in
+    --help | --hel | --he | --h)
+      exec echo "$help" ;;
+    --version | --versio | --versi | --vers | --ver | --ve | --v)
+      exec echo "$version" ;;
+    --)
+      shift
+      break ;;
+    -*)
+      echo "$0: invalid option: $arg" >&2
+      exit 1 ;;
+    *)
+      break ;;
+  esac
+done
+
+{ test $# -ge 1 && test $# -le 4; } ||
+{ echo "$0: $usage" >&2; exit 1; }
+
+# Arguments
+pathlist=$1
+mustexist=${2:-Y}
+separator=$3
+separator2=${4:-${separator}}
+
+# Split pathlist into its path components
+if test -n "$separator"
+then
+    IFS=${separator} patharray=( $pathlist )
+else
+    patharray=( "$pathlist" )
+fi
+
+# Output pathlist
+pathlist2=""
+
+for p in "${patharray[@]}"
+do
+    # Skip empty paths
+    test "$p" = "" && continue
+
+    # Replace '\' with '/', '//' with '/' and remove the final slash
+    # (if any).
+    p=${p//"\\"/"/"}
+    p=${p//\/\//"/"}
+    test ${#p} -gt 1 && p=${p%"/"}
+
+    if test -d "$p"
+    then
+	# The path exists, so just translate it
+	p2=`cd "$p" && pwd -W`
+    else
+	# The path does not exists.  So, try to guess the
+	# Windows-native translation
+
+	test "${mustexist}" = "Y" &&
+	{ echo "$0: invalid path: $p" >&2; exit 1; }
+	
+	# Look for the deepest existing directory in this path,
+	# testing with partial paths by removing one component from
+	# the right side in each iteration
+	IFS=/ pcomponents=( $p )
+	pa=$p
+
+	for (( i=${#pcomponents[@]}-1 ; i>=0 ; i-- ))
+	do
+
+	    if test "${pcomponents[i]}" = ""
+	    then
+		# The path component is empty.  This can only mean
+		# that the path starts with "/" and all components
+		# have been stripped out already.  So in this case
+		# "pa" must be set to the MSYS root directory
+		pa="/"
+	    else
+		pa=${pa%"/${pcomponents[i]}"}
+	    fi
+
+	    if test -d "${pa}"
+	    then
+
+		# Translate the existing part
+		p2=`cd "${pa}" && pwd -W`
+
+		# Remainder
+		pb="${p#${pa}}"
+
+		# Concatenate both parts (existing and remainder)
+		test "${p2}" = "/" || p2="${p2}/"
+		pb=${pb#/}
+		p2="${p2}${pb}"
+
+		break
+	    fi
+
+	done
+
+	# If no existing directory was found, error out
+	test -e "${pa}" ||
+	{ echo "$0: invalid path: ${p}" >&2; exit 1; }
+    fi
+
+    # Add this translated path to the translated pathlist
+    test "${pathlist2}" = "" || pathlist2="${pathlist2}${separator2}"
+    pathlist2="${pathlist2}${p2//${separator2}/\\${separator2}}"
+
+done
+
+# Write the translated pathlist to the standard output
+printf "${pathlist2}"
+
+## Local Variables:
+## eval: (add-hook 'write-file-functions 'time-stamp)
+## time-stamp-start: "VERSION='"
+## time-stamp-format: "%:y-%02m-%02d %02H:%02M"
+## time-stamp-time-zone: "UTC"
+## time-stamp-end: "'; # UTC"
+## End: