VVVVVV/desktop_version/version.cmake

# Expects INPUT_FILE and OUTPUT_FILE to be defined

# Get interim commit and date of commit
EXECUTE_PROCESS(
	COMMAND "${GIT_EXECUTABLE}" log -1 --format=%h
	OUTPUT_VARIABLE INTERIM_COMMIT
	OUTPUT_STRIP_TRAILING_WHITESPACE
)

EXECUTE_PROCESS(
	COMMAND "${GIT_EXECUTABLE}" log -1 --format=%cs
	OUTPUT_VARIABLE COMMIT_DATE
	OUTPUT_STRIP_TRAILING_WHITESPACE
)

MESSAGE(STATUS "This is interim commit ${INTERIM_COMMIT} (committed ${COMMIT_DATE})")

# Take the template file and replace the macros with what we have
CONFIGURE_FILE(${INPUT_FILE} ${OUTPUT_FILE})
Update commit hash every time it changes, not just when CMake is re-ran The commit hash is now properly updated every time it gets changed, and not just when CMake gets re-ran. For this to work, we need to use a few CMake tricks. We add a custom target with ADD_CUSTOM_TARGET(), which is apparently always considered out-of-date (but I had to add a BYPRODUCTS line to get it to actually work), and we use the target to run a .cmake file every time we build. Also, VVVVVV needs to depend on this custom target, to ensure that the game gets built AFTER the version gets generated - otherwise there'll be an error. So we do an ADD_DEPENDENCIES() after the ADD_EXECUTABLE() for VVVVVV. This file, version.cmake, is just the Version.h.out generation that I added previously, but the important thing about all of this is that if the contents of Version.h.out doesn't change, and thus if the commit hash hasn't changed, then CMake will never recompile and relink anything at all. (At least with the Ninja generator.) On a small note, since the Version.h.out generation is now a separate script that is guaranteed to get ran on every single build, while the Git FIND_PACKAGE() gets ran only at configure time, it is possible for the cached path of the Git executable to get out of date. Fixing this requires a simple re-configure (ideally), but in case it wasn't fixed, the INTERIM_COMMIT and COMMIT_DATE variables would get set to empty strings instead of containing a value. To prevent this from happening, I've removed ERROR_QUIET from the EXECUTE_PROCESS() calls in version.cmake, because it's better to explicitly error if the Git executable wasn't found than implicitly carry on like nothing happened. 2020-12-26 05:24:14 +01:00			`# Expects INPUT_FILE and OUTPUT_FILE to be defined`

			`# Get interim commit and date of commit`
			`EXECUTE_PROCESS(`
			`COMMAND "${GIT_EXECUTABLE}" log -1 --format=%h`
			`OUTPUT_VARIABLE INTERIM_COMMIT`
			`OUTPUT_STRIP_TRAILING_WHITESPACE`
			`)`

			`EXECUTE_PROCESS(`
			`COMMAND "${GIT_EXECUTABLE}" log -1 --format=%cs`
			`OUTPUT_VARIABLE COMMIT_DATE`
			`OUTPUT_STRIP_TRAILING_WHITESPACE`
			`)`

			`MESSAGE(STATUS "This is interim commit ${INTERIM_COMMIT} (committed ${COMMIT_DATE})")`

			`# Take the template file and replace the macros with what we have`
			`CONFIGURE_FILE(${INPUT_FILE} ${OUTPUT_FILE})`