More robust versioning in CMake, plus comments

src/version.cmake

@@ -1,22 +1,69 @@
+# Copyright (c) 2014, The Monero Project
+# 
+# All rights reserved.
+# 
+# Redistribution and use in source and binary forms, with or without modification, are
+# permitted provided that the following conditions are met:
+# 
+# 1. Redistributions of source code must retain the above copyright notice, this list of
+#    conditions and the following disclaimer.
+# 
+# 2. Redistributions in binary form must reproduce the above copyright notice, this list
+#    of conditions and the following disclaimer in the documentation and/or other
+#    materials provided with the distribution.
+# 
+# 3. Neither the name of the copyright holder nor the names of its contributors may be
+#    used to endorse or promote products derived from this software without specific
+#    prior written permission.
+# 
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+# THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+# STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+# THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+# 
+# Parts of this file are originally copyright (c) 2012-2013 The Cryptonote developers
+
+# Check what commit we're on
 execute_process(COMMAND "${GIT}" rev-parse --short HEAD RESULT_VARIABLE RET OUTPUT_VARIABLE COMMIT OUTPUT_STRIP_TRAILING_WHITESPACE)
 
 if(RET)
+	# Something went wrong, set the version tag to -unknown
+	
     message(WARNING "Cannot determine current commit. Make sure that you are building either from a Git working tree or from a source archive.")
     set(VERSIONTAG "unknown")
     configure_file("src/version.h.in" "${TO}")
 else()
 	message(STATUS "You are currently on commit ${COMMIT}")
+	
+	# Get all the tags
 	execute_process(COMMAND "${GIT}" show-ref --tags -d --abbrev RESULT_VARIABLE RET OUTPUT_VARIABLE TAGGEDCOMMITOUT OUTPUT_STRIP_TRAILING_WHITESPACE)
 	
+	# Make sure we actually got some tags
+	string(LENGTH ${TAGGEDCOMMITOUT} TLEN)
+	
+	if(RET OR TLEN LESS 5)
+	    message(WARNING "Cannot determine most recent tag. Make sure that you are building either from a Git working tree or from a source archive.")
+	    set(VERSIONTAG "${COMMIT}")		
+	else()
+		# Replace a bunch of things so we end up with a semi-colon separated list
 		string(REPLACE " refs/" "\n" TAGGEDCOMMITOUT2 ${TAGGEDCOMMITOUT})
 		string(REPLACE "\n" ";" TAGGEDCOMMITLIST ${TAGGEDCOMMITOUT2})
+		
+		# Grab the second-last item in the list, as that will be the hash of our most recent commit
 		list(GET TAGGEDCOMMITLIST -2 TAGGEDCOMMIT)
 
-	if(RET OR NOT TAGGEDCOMMIT)
+		if(NOT TAGGEDCOMMIT)
 			message(WARNING "Cannot determine most recent tag. Make sure that you are building either from a Git working tree or from a source archive.")
 			set(VERSIONTAG "${COMMIT}")
 		else()
 			message(STATUS "The most recent tag was at ${TAGGEDCOMMIT}")
+			
+			# Check if we're building that tagged commit or a different one
 			if(${COMMIT} MATCHES ${TAGGEDCOMMIT})
 				message(STATUS "You are building a tagged release")
 				set(VERSIONTAG "release")
@@ -26,5 +73,7 @@ else()
 			endif()
 		endif()	    
 
+	endif()
+
     configure_file("src/version.h.in" "${TO}")
 endif()