From 5859c235de96a8781ad63371d692334b20ecff18 Mon Sep 17 00:00:00 2001
From: Zack Weinberg <zackw@panix.com>
Date: Fri, 27 Apr 2012 09:32:51 -0400
Subject: [PATCH] Generate event-config.h with a single sed script

This approach should make the creation of the file more atomic, to
fix a bug reported by Dinh.

This patch has one change from Zack's original version: it avoids
$<, since Dave Hart tells me he thinks that's not so portable.

(commit message by nickm)
---
 Makefile.am           | 26 ++++++--------------------
 make-event-config.sed | 23 +++++++++++++++++++++++
 2 files changed, 29 insertions(+), 20 deletions(-)
 create mode 100644 make-event-config.sed

diff --git a/Makefile.am b/Makefile.am
index 7dee8864..19b3799f 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -103,6 +103,7 @@ EXTRA_DIST = \
 	autogen.sh \
 	event_rpcgen.py \
 	libevent.pc.in \
+	make-event-config.sed \
 	whatsnew-2.0.txt \
 	whatsnew-2.1.txt \
 	$(PLATFORM_DEPENDENT_SRC)
@@ -163,27 +164,12 @@ if SIGNAL_SUPPORT
 SYS_SRC += signal.c
 endif
 
-BUILT_SOURCES = ./include/event2/event-config.h
+BUILT_SOURCES = include/event2/event-config.h
 
-./include/event2/event-config.h: config.h Makefile.am
-	$(MKDIR_P) ./include/event2 || true
-	echo '/* event2/event-config.h' > $@
-	echo ' *' >> $@
-	echo ' * This file was generated by autoconf when libevent was built, and post-' >> $@
-	echo ' * processed by Libevent so that its macros would have a uniform prefix.' >> $@
-	echo ' *' >> $@
-	echo ' * DO NOT EDIT THIS FILE.' >> $@
-	echo ' *' >> $@
-	echo ' * Do not rely on macros in this file existing in later versions.'>> $@
-	echo ' */' >> $@
-	echo '#ifndef EVENT2_EVENT_CONFIG_H_INCLUDED_' >> $@
-	echo '#define EVENT2_EVENT_CONFIG_H_INCLUDED_' >> $@
-
-	sed -e 's/#define /#define EVENT__/' \
-	    -e 's/#undef /#undef EVENT__/' \
-	    -e 's/# define /# define EVENT__/' \
-	    -e 's/#ifndef /#ifndef EVENT__/' < config.h >> $@
-	echo "#endif" >> $@
+include/event2/event-config.h: config.h make-event-config.sed
+	test -d include/event2 || $(MKDIR_P) include/event2
+	$(SED) -f $(srcdir)/make-event-config.sed < config.h > $@T
+	mv -f $@T $@
 
 CORE_SRC =					\
 	buffer.c				\
diff --git a/make-event-config.sed b/make-event-config.sed
new file mode 100644
index 00000000..e31018a2
--- /dev/null
+++ b/make-event-config.sed
@@ -0,0 +1,23 @@
+# Sed script to postprocess config.h into event-config.h.
+
+1i\
+/* event2/event-config.h\
+ *\
+ * This file was generated by autoconf when libevent was built, and post-\
+ * processed by Libevent so that its macros would have a uniform prefix.\
+ *\
+ * DO NOT EDIT THIS FILE.\
+ *\
+ * Do not rely on macros in this file existing in later versions.\
+ */\
+\
+#ifndef EVENT2_EVENT_CONFIG_H_INCLUDED_\
+#define EVENT2_EVENT_CONFIG_H_INCLUDED_\
+
+$a\
+\
+#endif /* event2/event-config.h */
+
+s/#\( *\)define /#\1define EVENT__/
+s/#\( *\)undef /#\1undef EVENT__/
+s/#\( *\)if\(n*\)def /#\1if\2def EVENT__/