CMake/Modules/CMakeExpandImportedTargets.cmake

# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
# file LICENSE.rst or https://cmake.org/licensing for details.

#[=======================================================================[.rst:
CMakeExpandImportedTargets
--------------------------

.. deprecated:: 3.4

  This module should no longer be used.

  It was once needed to replace :ref:`Imported Targets` with their underlying
  libraries referenced on disk for use with the :command:`try_compile` and
  :command:`try_run` commands.  These commands now support imported targets in
  their ``LINK_LIBRARIES`` options (since CMake 2.8.11 for
  :command:`try_compile` command and since CMake 3.2 for :command:`try_run`
  command).

.. note::

  This module does not support the policy :policy:`CMP0022` ``NEW`` behavior,
  nor does it use the :prop_tgt:`INTERFACE_LINK_LIBRARIES` property, because
  :manual:`generator expressions <cmake-generator-expressions(7)>` cannot be
  evaluated at the configuration phase.

Functions
^^^^^^^^^

This module defines the following function:

.. command:: cmake_expand_imported_targets

  .. code-block:: cmake

    cmake_expand_imported_targets(
      <result-var>
      LIBRARIES <libs>...
      [CONFIGURATION <config>]
    )

  Expands all imported targets in a list of libraries ``<libs>...`` to their
  corresponding file paths on disk and stores the resulting list in a local
  variable ``<result-var>``.

  The options are:

  ``LIBRARIES``
    A :ref:`semicolon-separated list <CMake Language Lists>` of system and
    imported targets.  Imported targets in this list are replaced with their
    corresponding library file paths, including libraries from their link
    interfaces.

  ``CONFIGURATION``
    If this option is given, it uses the respective build configuration
    ``<config>`` of the imported targets if it exists.  If omitted, it defaults
    to the first entry in the :variable:`CMAKE_CONFIGURATION_TYPES` variable, or
    falls back to :variable:`CMAKE_BUILD_TYPE` if ``CMAKE_CONFIGURATION_TYPES``
    is not set.

Examples
^^^^^^^^

Using this module to get a list of library paths:

.. code-block:: cmake

  include(CMakeExpandImportedTargets)
  cmake_expand_imported_targets(
    expandedLibs
    LIBRARIES ${CMAKE_REQUIRED_LIBRARIES}
    CONFIGURATION "${CMAKE_TRY_COMPILE_CONFIGURATION}"
  )
#]=======================================================================]

function(CMAKE_EXPAND_IMPORTED_TARGETS _RESULT )

  set(options )
  set(oneValueArgs CONFIGURATION )
  set(multiValueArgs LIBRARIES )

  cmake_parse_arguments(CEIT "${options}" "${oneValueArgs}" "${multiValueArgs}"  ${ARGN})

  if(CEIT_UNPARSED_ARGUMENTS)
    message(FATAL_ERROR "Unknown keywords given to CMAKE_EXPAND_IMPORTED_TARGETS(): \"${CEIT_UNPARSED_ARGUMENTS}\"")
  endif()

  if(NOT CEIT_CONFIGURATION)
    # Would be better to test GENERATOR_IS_MULTI_CONFIG global property,
    # but the documented behavior specifically says we check
    # CMAKE_CONFIGURATION_TYPES and fall back to CMAKE_BUILD_TYPE if no
    # config types are defined.
    if(CMAKE_CONFIGURATION_TYPES)
      list(GET CMAKE_CONFIGURATION_TYPES 0 CEIT_CONFIGURATION)
    else()
      set(CEIT_CONFIGURATION ${CMAKE_BUILD_TYPE})
    endif()
  endif()

  # handle imported library targets

  set(_CCSR_REQ_LIBS ${CEIT_LIBRARIES})

  set(_CHECK_FOR_IMPORTED_TARGETS TRUE)
  set(_CCSR_LOOP_COUNTER 0)
  while(_CHECK_FOR_IMPORTED_TARGETS)
    math(EXPR _CCSR_LOOP_COUNTER "${_CCSR_LOOP_COUNTER} + 1 ")
    set(_CCSR_NEW_REQ_LIBS )
    set(_CHECK_FOR_IMPORTED_TARGETS FALSE)
    foreach(_CURRENT_LIB ${_CCSR_REQ_LIBS})
      if(TARGET "${_CURRENT_LIB}")
        get_target_property(_importedConfigs "${_CURRENT_LIB}" IMPORTED_CONFIGURATIONS)
      else()
        set(_importedConfigs "")
      endif()
      if (_importedConfigs)
        # message(STATUS "Detected imported target ${_CURRENT_LIB}")
        # Ok, so this is an imported target.
        # First we get the imported configurations.
        # Then we get the location of the actual library on disk of the first configuration.
        # then we'll get its link interface libraries property,
        # iterate through it and replace all imported targets we find there
        # with there actual location.

        # guard against infinite loop: abort after 100 iterations ( 100 is arbitrary chosen)
        if ("${_CCSR_LOOP_COUNTER}" LESS 100)
          set(_CHECK_FOR_IMPORTED_TARGETS TRUE)
#       else ()
#          message(STATUS "********* aborting loop, counter : ${_CCSR_LOOP_COUNTER}")
        endif ()

        # if one of the imported configurations equals ${CMAKE_TRY_COMPILE_CONFIGURATION},
        # use it, otherwise simply use the first one:
        list(FIND _importedConfigs "${CEIT_CONFIGURATION}" _configIndexToUse)
        if("${_configIndexToUse}" EQUAL -1)
          set(_configIndexToUse 0)
        endif()
        list(GET _importedConfigs ${_configIndexToUse} _importedConfigToUse)

        get_target_property(_importedLocation "${_CURRENT_LIB}" IMPORTED_LOCATION_${_importedConfigToUse})
        get_target_property(_linkInterfaceLibs "${_CURRENT_LIB}" IMPORTED_LINK_INTERFACE_LIBRARIES_${_importedConfigToUse} )

        list(APPEND _CCSR_NEW_REQ_LIBS  "${_importedLocation}")
#       message(STATUS "Appending lib ${_CURRENT_LIB} as ${_importedLocation}")
        if(_linkInterfaceLibs)
          foreach(_currentLinkInterfaceLib ${_linkInterfaceLibs})
#           message(STATUS "Appending link interface lib ${_currentLinkInterfaceLib}")
            if(_currentLinkInterfaceLib)
              list(APPEND _CCSR_NEW_REQ_LIBS "${_currentLinkInterfaceLib}" )
            endif()
          endforeach()
        endif()
      else()
        # "Normal" libraries are just used as they are.
        list(APPEND _CCSR_NEW_REQ_LIBS "${_CURRENT_LIB}" )
#       message(STATUS "Appending lib directly: ${_CURRENT_LIB}")
      endif()
    endforeach()
    set(_CCSR_REQ_LIBS ${_CCSR_NEW_REQ_LIBS} )
  endwhile()

  # Finally we iterate once more over all libraries. This loop only removes
  # all remaining imported target names (there shouldn't be any left anyway).
  set(_CCSR_NEW_REQ_LIBS )
  foreach(_CURRENT_LIB ${_CCSR_REQ_LIBS})
    if(TARGET "${_CURRENT_LIB}")
      get_target_property(_importedConfigs "${_CURRENT_LIB}" IMPORTED_CONFIGURATIONS)
    else()
      set(_importedConfigs "")
    endif()
    if (NOT _importedConfigs)
      list(APPEND _CCSR_NEW_REQ_LIBS "${_CURRENT_LIB}" )
#     message(STATUS "final: appending ${_CURRENT_LIB}")
#   else ()
#   message(STATUS "final: skipping ${_CURRENT_LIB}")
    endif ()
  endforeach()
# message(STATUS "setting -${_RESULT}- to -${_CCSR_NEW_REQ_LIBS}-")
  set(${_RESULT} "${_CCSR_NEW_REQ_LIBS}" PARENT_SCOPE)

endfunction()