[vcpkg] Add vcpkg_check_features

[myd7349]

When working on #4979, I realized this pattern has been repeated too much:

if(<feature> IN_LIST FEATURES)
    set(<var> ON)
else()
   set(<var> OFF)
endif()

vcpkg_config_cmake(
    ...
    OPTIONS
        -D<var>=${var}
)

So it is time to create a little shiny macro/function for this.

czmq has a lot of optional libraries:

if("draft" IN_LIST FEATURES)
    set(ENABLE_DRAFTS ON)
else()
    set(ENABLE_DRAFTS OFF)
endif()

if("httpd" IN_LIST FEATURES)
    set(CZMQ_WITH_LIBMICROHTTPD ON)
else()
    set(CZMQ_WITH_LIBMICROHTTPD OFF)
endif()

if("tool" IN_LIST FEATURES)
    set(BUILD_TOOLS ON)
else()
    set(BUILD_TOOLS OFF)
endif()

if("curl" IN_LIST FEATURES)
    set(CZMQ_WITH_LIBCURL ON)
else()
    set(CZMQ_WITH_LIBCURL OFF)
endif()

if("lz4" IN_LIST FEATURES)
    set(CZMQ_WITH_LZ4 ON)
else()
    set(CZMQ_WITH_LZ4 OFF)
endif()

if("uuid" IN_LIST FEATURES AND
   VCPKG_CMAKE_SYSTEM_NAME STREQUAL "Linux")
    set(CZMQ_WITH_UUID ON)
else()
    set(CZMQ_WITH_UUID OFF)
endif()

vcpkg_configure_cmake(
    SOURCE_PATH ${SOURCE_PATH}
    PREFER_NINJA
    OPTIONS
        -DENABLE_DRAFTS=${ENABLE_DRAFTS}
        -DCZMQ_WITH_LIBMICROHTTPD=${CZMQ_WITH_LIBMICROHTTPD}
        -DCZMQ_WITH_UUID=${CZMQ_WITH_UUID}
        -DCZMQ_WITH_LIBCURL=${CZMQ_WITH_LIBCURL}
        -DCZMQ_WITH_LZ4=${CZMQ_WITH_LZ4}
)

This patch provides a macro(vcpkg_check_feature) and a function(vcpkg_check_features). With the help of this new module, it can be simplified as:

vcpkg_check_feature(draft ENABLE_DRAFTS)
vcpkg_check_feature(httpd CZMQ_WITH_LIBMICROHTTPD)
vcpkg_check_feature(tool BUILD_TOOLS)
vcpkg_check_feature(lz4 CZMQ_WITH_LZ4)
vcpkg_check_feature(curl CZMQ_WITH_LIBCURL)

if("uuid" IN_LIST FEATURES AND
   VCPKG_CMAKE_SYSTEM_NAME STREQUAL "Linux")
    set(CZMQ_WITH_UUID ON)
else()
    set(CZMQ_WITH_UUID OFF)
endif()

vcpkg_configure_cmake(
    SOURCE_PATH ${SOURCE_PATH}
    PREFER_NINJA
    OPTIONS
        -DENABLE_DRAFTS=${ENABLE_DRAFTS}
        -DCZMQ_WITH_LIBCURL=${CZMQ_WITH_LIBCURL}
        -DCZMQ_WITH_LIBMICROHTTPD=${CZMQ_WITH_LIBMICROHTTPD}
        -DCZMQ_WITH_LZ4=${CZMQ_WITH_LZ4}
        -DCZMQ_WITH_UUID=${CZMQ_WITH_UUID}
)

or

vcpkg_check_features(
    draft ENABLE_DRAFTS
    httpd CZMQ_WITH_LIBMICROHTTPD
    tool BUILD_TOOLS
    lz4 CZMQ_WITH_LZ4
    curl CZMQ_WITH_LIBCURL
)

if("uuid" IN_LIST FEATURES AND
   VCPKG_CMAKE_SYSTEM_NAME STREQUAL "Linux")
    set(CZMQ_WITH_UUID ON)
else()
    set(CZMQ_WITH_UUID OFF)
endif()

vcpkg_configure_cmake(
    SOURCE_PATH ${SOURCE_PATH}
    PREFER_NINJA
    OPTIONS
        -DCZMQ_WITH_UUID=${CZMQ_WITH_UUID}
        ${FEATURE_OPTIONS}
)

[myd7349]

I still have the following concerns:

1. Is defining two new functions in one .cmake a good pattern?
2. Is it easy to distinguish between vcpkg_check_feature and vcpkg_check_features?
3. Is vcpkg_check_feature(s) a good name?
4. Does the syntax of vcpkg_check_features look weired?

[Rastaban]

I'm not sure having two separate macros is needed. I lean toward just vcpkg_check_features (unless others decide it looks weird) because it can still be called with one set of arguments.

[myd7349]

@Rastaban Thanks! That sounds resonable to me.

[myd7349]

TODO: Take this form into consideration:

if(<option> MATCHES "ON")
endif()

https://github.com/microsoft/mimalloc/blob/91222691cb21a6fb7a9760a264ff1183a1237fd4/CMakeLists.txt#L45
That is, we should allow the user to choose between ON/OFF, 1/0, TRUE/FALSE.
#7011

[cbezault]

Agreed with @Rastaban, drop the singular version.

[myd7349]

@cbezault Thanks for your reply!

[cbezault]

vcpkg_check_features

[cbezault]

Could you modify one port to use this new feature and add it to this PR?

[myd7349]

Could you modify one port to use this new feature and add it to this PR?

Thanks! Done.

[myd7349]

Oops! It seems that I made a mistake here:

if("non-posix" IN_LIST FEATURES)
    set(ENABLE_POSIX_API OFF) # Not `ON` here
else()
    set(ENABLE_POSIX_API ON)
endif()

can not be replaced with:

vcpkg_check_features(non-posix ENABLE_POSIX_API)

I will fix it.

[myd7349]

#7091