[cmake-developers] [PATCH] FindProtobuf: check version

[Rolf Eike Beer]

> +
> +  set(Protobuf_VERSION 0)

Just set it to an empty string.

> +  set(Protobuf_LIB_VERSION "")
> +  file(STRINGS ${_Protobuf_COMMON_HEADER} _Protobuf_COMMON_H_CONTENTS
> REGEX "#define GOOGLE_PROTOBUF_VERSION ")

I would replace the spaces with "[ \t]+" so a formatting change will not 
break the extraction, also below.

> +  set(_Protobuf_VERSION_REGEX "([0-9]+)")

No need for that variable, just put it into the matches argument below.

> +  if("${_Protobuf_COMMON_H_CONTENTS}" MATCHES "#define
> GOOGLE_PROTOBUF_VERSION ${_Protobuf_VERSION_REGEX}")
> +    set(Protobuf_VERSION "${CMAKE_MATCH_1}")
> +  endif()
> +  unset(_Protobuf_COMMON_H_CONTENTS)
> +
> +  math(EXPR Protobuf_MAJOR_VERSION "${Protobuf_VERSION} / 1000000")
> +  math(EXPR Protobuf_MINOR_VERSION "${Protobuf_VERSION} / 1000 % 
> 1000")
> +  math(EXPR Protobuf_SUBMINOR_VERSION "${Protobuf_VERSION} % 1000")

You are not required to export these variables, only if you expect it to 
be useful for something beyond version checking. If anyone needs 
specific version fiddling Protobuf_VERSION can be used.

Eike