#use git for a pretty commit id

#uses 'git describe --tags', so tags are required in the repo

#create a tag with 'git tag <name>' and 'git push --tags'

#version_string.hpp will define VERSION_STRING to something like "test-1-g5e1fb47"

# where test is the name of the last tagged git revision, 1 is the number of commits since that tag,

# 'g' is ???, and 5e1fb47 is the first 7 chars of the git sha1 commit id.

find_package(Git)

if(NOT GIT_FOUND)

# cmake 2.8.1 (in Lucid) does not have a git Cmake interface

# cmake 2.8.5 (in Oneiric) does have it

message(STATUS "couldn't find Cmake interface to git, old version of Cmake? looking by hand...")

execute_process(

COMMAND git --version

RESULT_VARIABLE RC

)

if (${RC} EQUAL 0)

set(GIT_FOUND 1)

set(GIT_EXECUTABLE "git")

else()

message(ERROR "couldn't run git executable!")

endif()

endif()

if(GIT_FOUND)

execute_process(

WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}

COMMAND ${GIT_EXECUTABLE} describe --tags

RESULT_VARIABLE res_var

OUTPUT_VARIABLE GIT_COM_ID

OUTPUT_STRIP_TRAILING_WHITESPACE

ERROR_QUIET

)

if( NOT ${res_var} EQUAL 0 )

message( WARNING "Git failed (not a repo, or no tags)." )

file(READ "git-tag.txt" GIT_COMMIT_ID)

message( STATUS "version_string.cmake read from file GIT_COMMIT_ID: " ${GIT_COMMIT_ID})

else()

string( REPLACE "\n" "" GIT_COMMIT_ID ${GIT_COM_ID} )

message( STATUS "version_string.cmake git set GIT_COMMIT_ID: " ${GIT_COMMIT_ID})

endif()

else()

# if we don't have git, try to read git-tag from file instead

file(READ "git-tag.txt" GIT_COMMIT_ID)

#set( GIT_COMMIT_ID "unknown (git not found!)")

message( STATUS "version_string.cmake read from file git-tag.txt: " ${GIT_COMMIT_ID})

#message( WARNING "Git not found. Reading tag from git-tag.txt instead: " ${GIT_COMMIT_ID})

endif()

set( vstring "//version_string.hpp - written by cmake. changes will be lost!\n"

"#ifndef VERSION_STRING\n"

"#define VERSION_STRING \"${GIT_COMMIT_ID}\"\n"

"#endif\n"

)

file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/version_string.hpp ${vstring} )

set_source_files_properties(

${CMAKE_CURRENT_BINARY_DIR}/version_string.hpp

PROPERTIES GENERATED TRUE

HEADER_FILE_ONLY TRUE

)

# copy the file to the final header only if the version changes

# reduces needless rebuilds

#execute_process(COMMAND ${CMAKE_COMMAND} -E copy_if_different

# version_string.hpp.txt /version_string.hpp)