Fix DX_COMMAND_OUTPUT backslash-newline on heirloom-sh.

[dxcommon.git] / m4 / cmdout.m4

diff --git a/m4/cmdout.m4 b/m4/cmdout.m4
index 5aa39253b397a67e2a3d9f6c2b4c47c661ba34ae..c91aca1057ec131be2c179dc7ffa1facd99c29b4 100644 (file)
--- a/m4/cmdout.m4
+++ b/m4/cmdout.m4
@@ -1,4 +1,4 @@
-dnl Copyright © 2014 Nick Bowler
+dnl Copyright © 2014-2015 Nick Bowler
 dnl
 dnl License WTFPL2: Do What The Fuck You Want To Public License, version 2.
 dnl This is free software: you are free to do what the fuck you want to.
@@ -7,30 +7,37 @@ dnl There is NO WARRANTY, to the extent permitted by law.
 dnl DX_COMMAND_OUTPUT(variable, command, [action-if-ok], [action-if-failed])
 dnl
 dnl Helper to capture standard output of a shell command.  If the command
-dnl is successful then variable is assigned with its output (with newlines
-dnl converted to spaces), and action-if-ok is performed.  Otherwise, if
-dnl the command is unsuccessful, then variable is not changed, and
-dnl action-if-failed is performed.
+dnl is successful then variable is assigned with its output, and action-if-ok
+dnl is performed.  Otherwise, if the command is unsuccessful, then variable
+dnl is not changed, and action-if-failed is performed.
 AC_DEFUN([DX_COMMAND_OUTPUT], [AC_REQUIRE([_DX_COMMAND_OUTPUT_SETUP])dnl
-AS_IF([$2 >conftest.out 2>&AS_MESSAGE_LOG_FD],
-       [m4_do([dx_fn_cmdout_collect_output $1],
-               [m4_ifnblank([$3], [m4_newline([$3])])])],
-       [$4])
-rm -f conftest.out
-])
+AS_IF([$2 >conftest.do0 2>&AS_MESSAGE_LOG_FD],
+  [m4_do([dx_fn_cmdout_collect_output $1],
+    [m4_ifnblank([$3], [m4_newline([$3])])])],
+  [$4])
+rm -f conftest.do0 conftest.do1])
 
 AC_DEFUN_ONCE([_DX_COMMAND_OUTPUT_SETUP], [m4_divert_push([INIT_PREPARE])dnl
-# Helper function to store the contents of conftest.out into a shell variable.
+# Helper function to store the contents of conftest.do0 into a shell variable.
 dx_fn_cmdout_collect_output () {
   AS_UNSET([$][1])
-  exec 3<conftest.out
+  # Double up backslashes as they will be stripped by read.
+  # Heirloom sh read apparently just eats backslashes at EOL, so we compromise
+  # by adding a marker that can be stripped out afterwards.
+  _dx_eol='@%eol@%'
+  sed -e 's/\\/\\\\/g' -e 's/\\$/\\'"$_dx_eol/" conftest.do0 >conftest.do1 ||
+    return
+  exec 3<conftest.do1
   _dx_save_IFS=$IFS
-  IFS=
-  while read _dx_tmp <&3
+  while IFS=; read _dx_tmp <&3
   do
-AS_VAR_SET_IF([$][1],
-       [AS_VAR_APPEND([$][1], [" $_dx_tmp"])],
-       [AS_VAR_SET([$][1], [$_dx_tmp])])
+    IFS=$_dx_save_IFS
+    # strip out EOL marker, if present
+    AS_CASE([$_dx_tmp], [*"\\$_dx_eol"],
+      [_dx_tmp=`AS_ECHO(["$_dx_tmp"]) | sed "s/$_dx_eol\$//"`])
+    AS_VAR_SET_IF([$][1],
+      [AS_VAR_APPEND([$][1], ["$as_nl$_dx_tmp"])],
+      [AS_VAR_SET([$][1], [$_dx_tmp])])
   done
   IFS=$_dx_save_IFS
   exec 3<&-