[CMake] Report git revision information if available.

This is done as a separate commit because it imports
third party code. It's under the Boost license though
so it "should be" fine.

2 files changed, 171 insertions, 0 deletions

diff --git a/cmake/GetGitRevisionDescription.cmake b/cmake/GetGitRevisionDescription.cmake
new file mode 100644
index 00000000..85eae156
--- /dev/null
+++ b/cmake/GetGitRevisionDescription.cmake
@@ -0,0 +1,130 @@
+# - Returns a version string from Git
+#
+# These functions force a re-configure on each git commit so that you can
+# trust the values of the variables in your build system.
+#
+#  get_git_head_revision(<refspecvar> <hashvar> [<additional arguments to git describe> ...])
+#
+# Returns the refspec and sha hash of the current head revision
+#
+#  git_describe(<var> [<additional arguments to git describe> ...])
+#
+# Returns the results of git describe on the source tree, and adjusting
+# the output so that it tests false if an error occurs.
+#
+#  git_get_exact_tag(<var> [<additional arguments to git describe> ...])
+#
+# Returns the results of git describe --exact-match on the source tree,
+# and adjusting the output so that it tests false if there was no exact
+# matching tag.
+#
+# Requires CMake 2.6 or newer (uses the 'function' command)
+#
+# Original Author:
+# 2009-2010 Ryan Pavlik <rpavlik@iastate.edu> <abiryan@ryand.net>
+# http://academic.cleardefinition.com
+# Iowa State University HCI Graduate Program/VRAC
+#
+# Copyright Iowa State University 2009-2010.
+# Distributed under the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE_1_0.txt or copy at
+# http://www.boost.org/LICENSE_1_0.txt)
+
+if(__get_git_revision_description)
+	return()
+endif()
+set(__get_git_revision_description YES)
+
+# We must run the following at "include" time, not at function call time,
+# to find the path to this module rather than the path to a calling list file
+get_filename_component(_gitdescmoddir ${CMAKE_CURRENT_LIST_FILE} PATH)
+
+function(get_git_head_revision _refspecvar _hashvar)
+	set(GIT_PARENT_DIR "${CMAKE_CURRENT_SOURCE_DIR}")
+	set(GIT_DIR "${GIT_PARENT_DIR}/.git")
+	while(NOT EXISTS "${GIT_DIR}")	# .git dir not found, search parent directories
+		set(GIT_PREVIOUS_PARENT "${GIT_PARENT_DIR}")
+		get_filename_component(GIT_PARENT_DIR ${GIT_PARENT_DIR} PATH)
+		if(GIT_PARENT_DIR STREQUAL GIT_PREVIOUS_PARENT)
+			# We have reached the root directory, we are not in git
+			set(${_refspecvar} "GITDIR-NOTFOUND" PARENT_SCOPE)
+			set(${_hashvar} "GITDIR-NOTFOUND" PARENT_SCOPE)
+			return()
+		endif()
+		set(GIT_DIR "${GIT_PARENT_DIR}/.git")
+	endwhile()
+	# check if this is a submodule
+	if(NOT IS_DIRECTORY ${GIT_DIR})
+		file(READ ${GIT_DIR} submodule)
+		string(REGEX REPLACE "gitdir: (.*)\n$" "\\1" GIT_DIR_RELATIVE ${submodule})
+		get_filename_component(SUBMODULE_DIR ${GIT_DIR} PATH)
+		get_filename_component(GIT_DIR ${SUBMODULE_DIR}/${GIT_DIR_RELATIVE} ABSOLUTE)
+	endif()
+	set(GIT_DATA "${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/git-data")
+	if(NOT EXISTS "${GIT_DATA}")
+		file(MAKE_DIRECTORY "${GIT_DATA}")
+	endif()
+
+	if(NOT EXISTS "${GIT_DIR}/HEAD")
+		return()
+	endif()
+	set(HEAD_FILE "${GIT_DATA}/HEAD")
+	configure_file("${GIT_DIR}/HEAD" "${HEAD_FILE}" COPYONLY)
+
+	configure_file("${_gitdescmoddir}/GetGitRevisionDescription.cmake.in"
+		"${GIT_DATA}/grabRef.cmake"
+		@ONLY)
+	include("${GIT_DATA}/grabRef.cmake")
+
+	set(${_refspecvar} "${HEAD_REF}" PARENT_SCOPE)
+	set(${_hashvar} "${HEAD_HASH}" PARENT_SCOPE)
+endfunction()
+
+function(git_describe _var)
+	if(NOT GIT_FOUND)
+		find_package(Git QUIET)
+	endif()
+	get_git_head_revision(refspec hash)
+	if(NOT GIT_FOUND)
+		set(${_var} "GIT-NOTFOUND" PARENT_SCOPE)
+		return()
+	endif()
+	if(NOT hash)
+		set(${_var} "HEAD-HASH-NOTFOUND" PARENT_SCOPE)
+		return()
+	endif()
+
+	# TODO sanitize
+	#if((${ARGN}" MATCHES "&&") OR
+	#	(ARGN MATCHES "||") OR
+	#	(ARGN MATCHES "\\;"))
+	#	message("Please report the following error to the project!")
+	#	message(FATAL_ERROR "Looks like someone's doing something nefarious with git_describe! Passed arguments ${ARGN}")
+	#endif()
+
+	#message(STATUS "Arguments to execute_process: ${ARGN}")
+
+	execute_process(COMMAND
+		"${GIT_EXECUTABLE}"
+		describe
+		${hash}
+		${ARGN}
+		WORKING_DIRECTORY
+		"${CMAKE_CURRENT_SOURCE_DIR}"
+		RESULT_VARIABLE
+		res
+		OUTPUT_VARIABLE
+		out
+		ERROR_QUIET
+		OUTPUT_STRIP_TRAILING_WHITESPACE)
+	if(NOT res EQUAL 0)
+		set(out "${out}-${res}-NOTFOUND")
+	endif()
+
+	set(${_var} "${out}" PARENT_SCOPE)
+endfunction()
+
+function(git_get_exact_tag _var)
+	git_describe(out --exact-match ${ARGN})
+	set(${_var} "${out}" PARENT_SCOPE)
+endfunction()
diff --git a/cmake/GetGitRevisionDescription.cmake.in b/cmake/GetGitRevisionDescription.cmake.in
new file mode 100644
index 00000000..6d8b708e
--- /dev/null
+++ b/cmake/GetGitRevisionDescription.cmake.in
@@ -0,0 +1,41 @@
+#
+# Internal file for GetGitRevisionDescription.cmake
+#
+# Requires CMake 2.6 or newer (uses the 'function' command)
+#
+# Original Author:
+# 2009-2010 Ryan Pavlik <rpavlik@iastate.edu> <abiryan@ryand.net>
+# http://academic.cleardefinition.com
+# Iowa State University HCI Graduate Program/VRAC
+#
+# Copyright Iowa State University 2009-2010.
+# Distributed under the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE_1_0.txt or copy at
+# http://www.boost.org/LICENSE_1_0.txt)
+
+set(HEAD_HASH)
+
+file(READ "@HEAD_FILE@" HEAD_CONTENTS LIMIT 1024)
+
+string(STRIP "${HEAD_CONTENTS}" HEAD_CONTENTS)
+if(HEAD_CONTENTS MATCHES "ref")
+	# named branch
+	string(REPLACE "ref: " "" HEAD_REF "${HEAD_CONTENTS}")
+	if(EXISTS "@GIT_DIR@/${HEAD_REF}")
+		configure_file("@GIT_DIR@/${HEAD_REF}" "@GIT_DATA@/head-ref" COPYONLY)
+	else()
+		configure_file("@GIT_DIR@/packed-refs" "@GIT_DATA@/packed-refs" COPYONLY)
+		file(READ "@GIT_DATA@/packed-refs" PACKED_REFS)
+		if(${PACKED_REFS} MATCHES "([0-9a-z]*) ${HEAD_REF}")
+			set(HEAD_HASH "${CMAKE_MATCH_1}")
+		endif()
+	endif()
+else()
+	# detached HEAD
+	configure_file("@GIT_DIR@/HEAD" "@GIT_DATA@/head-ref" COPYONLY)
+endif()
+
+if(NOT HEAD_HASH)
+	file(READ "@GIT_DATA@/head-ref" HEAD_HASH LIMIT 1024)
+	string(STRIP "${HEAD_HASH}" HEAD_HASH)
+endif()