configury: switch to _ax_text_tpl.m4

The script generation Makefile snippets are now used from
_ax_text_tpl.m4, DRY principle (the m4 file is maintained
separately for multiple projects).

* configure.ac: Remove all the manual work with substitutions,
start using _AX_TEXT_* macros.
* Makefile.am: Use $(text_tpl_gen*) variables from _ax_text_tpl.
* tests/Makefile.am: Likewise.
* share/postgresql-setup/Makefile.inc: Likewise.
* m4/_ax_text_tpl.m4: New file, TODO: publish somewhere.
* m4/packaging.m4: Reuse _ax_text_tpl.

2 files changed, 164 insertions, 1 deletions

diff --git a/m4/_ax_text_tpl.m4 b/m4/_ax_text_tpl.m4
new file mode 100644
index 0000000..971096a
--- /dev/null
+++ b/m4/_ax_text_tpl.m4
@@ -0,0 +1,162 @@
+# Text templating system with autoconf
+# ====================================
+#
+# Correctly generate files based on ./configure check results.  The @variable@
+# substitution is usually done by config.status from *.in files, however
+# substuing paths like @libexecdir@ can result into '${exec_prefix}/libexec'
+# which is not desired for installed scripts, for example, where we need to have
+# fully expanded paths.  The aim of this script is to generalize steps users
+# usually do to perform full expansion of configure variables.  Currently we use
+# sed substitution only.
+#
+# The easiest usage of this templating system is like this:
+#   $ cat configure.ac | "grep interresting lines"
+#   _AX_TEXT_TPL_INIT
+#   some_other_var="some other var content"
+#   _AX_TEXT_TPL_SUBST([some_other_var])
+#
+#   $ cat Makefile (or Makefile.am):
+#   generated_file: TEMPLATE.in $(text_tpl_deps)
+#   <<tab>>$(text_tpl_gen)
+#
+# Limitations:
+# - this code is probably not terribly portable
+# - substitutions should not contain '|' character (because we use sed rules
+#   spelled like 's|||'), you can do things like '\|', however you need to
+#   take into account that substitution done by 'sed' and by 'config.status' are
+#   not the same.  Also be careful about escaping '\' caracter.
+# - only single-line substitutions are expected;  you may use '\n' however
+#   there is the same problem as with '|' and '\'.
+#
+# TODO:
+# - we should do something similar to what config.status does (awk generated
+#   source code for substitutions), however even thought usually variable
+#   (macro) values are defined by ./configure, some may be defined like 'make
+#   VARIABLE=VALUE'.
+
+# sed_subst_var_pattern VARNAME (private macro)
+# ---------------------------------------------
+# Generate sed substitution rule to substitute @VARNAME@ with fully expaned
+# value of $VARNAME.  The trick is that we use 'make' to expand the value.
+# The VARNAME must be AC_SUBST'ed (and all its sub-components like ${prefix},
+# etc.) to allow 'make' doing correct expansion.
+m4_define([sed_subst_var_pattern], [\\
+	-e 's|@$1[[@]]|\$($1)|g'])
+
+# _AX_TEXT_TPL_INIT
+# -----------------
+# Initialize the templating system.
+AC_DEFUN([_AX_TEXT_TPL_INIT], [
+
+__ax_text_tpl_default_variables="\
+    abs_builddir
+    abs_srcdir
+    abs_top_builddir
+    abs_top_srcdir
+    bindir
+    build_alias
+    builddir
+    datarootdir
+    datadir
+    docdir
+    dvidir
+    exec_prefix
+    host_alias
+    htmldir
+    includedir
+    infodir
+    libdir
+    libexecdir
+    localedir
+    localstatedir
+    mandir
+    oldincludedir
+    pdfdir
+    pkgdatadir
+    prefix
+    psdir
+    sbindir
+    sharedstatedir
+    srcdir
+    sysconfdir
+    target_alias
+    top_srcdir
+    PACKAGE
+    PACKAGE_BUGREPORT
+    PACKAGE_NAME
+    PACKAGE_STRING
+    PACKAGE_TARNAME
+    PACKAGE_URL
+    PACKAGE_VERSION
+    PATH_SEPARATOR
+    SHELL
+    VERSION
+"
+
+__ax_text_tpl_sed_rules=""
+for i in $__ax_text_tpl_default_variables
+do
+__ax_text_tpl_sed_rules="$__ax_text_tpl_sed_rules \
+sed_subst_var_pattern($i)"
+done
+
+__ax_text_tpl_sed_rules="$__ax_text_tpl_sed_rules \\
+	\$(__ax_text_tpl_user_sed_rules) \\
+	\$(_AX_TEXT_ADDITIONAL_SED_SUBSTITUTIONS) \\
+	\$\$ax_text_add_sed_substs \\
+	-e 's|@__FILE__[[@]]|\@S|@@|g'"
+
+__ax_text_tpl_sed_call="\$(SED) \$(__ax_text_tpl_sed_rules)"
+text_tpl_sed_call=$__ax_text_tpl_sed_call
+m4_pattern_allow(AM_V_GEN)
+
+# Convenient snippet to clean & prepare for following build
+text_tpl_gen_conv_verbose="rm -rf \@S|@@; \$(MKDIR_P) \$(@D)"
+text_tpl_gen_conv="\$(AM_V_GEN)\$(text_tpl_gen_conv_verbose)"
+
+# Instantiate arbitrary data text file
+text_tpl_gen_verbose="\$(text_tpl_gen_conv_verbose) && \$(__ax_text_tpl_sed_call) \$< > \@S|@@ && chmod -w \@S|@@"
+text_tpl_gen="\$(AM_V_GEN)\$(text_tpl_gen_verbose)"
+
+# Instantiate script file
+text_tpl_gen_script_verbose="\$(text_tpl_gen_verbose) && chmod +x \@S|@@"
+text_tpl_gen_script="\$(AM_V_GEN)\$(text_tpl_gen_script_verbose) && chmod +x \@S|@@"
+
+# Make dependencies for targets of $(text_tpl_gen) and $(text_tpl_gen_script)
+text_tpl_deps='$(top_builddir)/config.status'
+
+AC_PATH_PROG([SED], [sed])
+test -z "$ac_cv_path_SED" &&
+    AC_MSG_ERROR([Sed is needed but not found.])
+
+AC_SUBST([__ax_text_tpl_sed_call])
+AC_SUBST([__ax_text_tpl_sed_rules])
+AC_SUBST([__ax_text_tpl_user_sed_rules])
+AC_SUBST([text_tpl_deps])
+AC_SUBST([text_tpl_sed_call])
+AC_SUBST([text_tpl_gen])
+AC_SUBST([text_tpl_gen_verbose])
+AC_SUBST([text_tpl_gen_conv])
+AC_SUBST([text_tpl_gen_conv_verbose])
+AC_SUBST([text_tpl_gen_script])
+AC_SUBST([text_tpl_gen_script_verbose])
+])
+
+# _AX_TEXT_TPL_SUBST SHELL_VARNAME
+# --------------------------------
+# Do substitution of SHELL_VARNAME both by config.status, and by sed call
+# in instantiation rules.
+AC_DEFUN([_AX_TEXT_TPL_SUBST], [
+__ax_text_tpl_user_sed_rules="$__ax_text_tpl_user_sed_rules\
+sed_subst_var_pattern($1)"
+AC_SUBST($1)
+])
+
+
+# _AX_TEXT_TPL_ARG_VAR VARNAME DEFAULT DESCRIPTION
+# ------------------------------------------------
+AC_DEFUN([_AX_TEXT_TPL_ARG_VAR], [
+AC_ARG_VAR([$1], [$3])
+test -z "$$1" && $1=$2
+_AX_TEXT_TPL_SUBST($1)
+])
diff --git a/m4/packaging.m4 b/m4/packaging.m4
index a50c4ba..3d166d3 100644
--- a/m4/packaging.m4
+++ b/m4/packaging.m4
@@ -29,6 +29,7 @@ AC_DEFUN([PGSETUP_PACKAGING_INIT], [
 # comment.
 m4_define([PGSETUP_SUBST_REQ], [
     AC_ARG_VAR([$1], [$2])
+    _AX_TEXT_TPL_SUBST([$1])
     test -z "$[]$1" &&
         AC_MSG_ERROR([the \$$1 variable is not set])
 ])
@@ -39,5 +40,5 @@ m4_define([PGSETUP_SUBST_OPT], [
     AC_ARG_VAR([$1], [$3])
     test -z "$[]$1" &&
         $1=$2
-    add_sed_subst_var($1)
+    _AX_TEXT_TPL_SUBST($1)
 ])