From fd4540d5736b0f498dd84838ad98ba100c499513 Mon Sep 17 00:00:00 2001
From: Nicolas Hake <isilkor@openclonk.org>
Date: Sun, 5 Feb 2012 02:08:45 +0100
Subject: [PATCH] cmake: Read Mercurial revision from .hg_archival.txt if
 available

This way cmake will generate a correct C4Version.h from source tarballs
generated by hg archive.
---
 Version.txt | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/Version.txt b/Version.txt
index f43838141..e1bce26bd 100644
--- a/Version.txt
+++ b/Version.txt
@@ -35,12 +35,20 @@ SET(C4VERSIONEXTRA      " Alpha")
 ############################################################################
 # Get revision from Mercurial
 ############################################################################
-
-# Note: This will not work for source distributions!
-execute_process(WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
-	COMMAND "hg" "id" "--id"
-	OUTPUT_VARIABLE C4REVISION
-	OUTPUT_STRIP_TRAILING_WHITESPACE)
+if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/.hg_archival.txt")
+	# Archives generated by hg archive
+	file(STRINGS "${CMAKE_CURRENT_SOURCE_DIR}/.hg_archival.txt" C4REVISION
+		LIMIT_COUNT 1
+		REGEX "node: [0-9a-f]+"
+	)
+	string(SUBSTRING "${C4REVISION}" 6 12 C4REVISION)
+else()
+	# Working copies
+	execute_process(WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+		COMMAND "hg" "id" "--id"
+		OUTPUT_VARIABLE C4REVISION
+		OUTPUT_STRIP_TRAILING_WHITESPACE)
+endif()
 
 ############################################################################
 # Build version strings