#
# 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()
