OpenCensusHelpers.cmake

# Copyright 2018, OpenCensus Authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Prepends opencensus_ to all deps that aren't in a :: namespace.
function(prepend_opencensus OUT DEPS)
  set(_DEPS "")
  foreach(dep ${DEPS})
    if("${dep}" MATCHES "::")
      list(APPEND _DEPS "$<BUILD_INTERFACE:${dep}>")
    else()
      list(APPEND _DEPS "opencensus_${dep}")
    endif()
  endforeach()
  set(${OUT}
      ${_DEPS}
      PARENT_SCOPE)
endfunction()

# Helper function like bazel's cc_test. Usage:
#
# opencensus_test(trace_some_test internal/some_test.cc dep1 dep2...)
function(opencensus_test NAME SRC)
  if(BUILD_TESTING)
    set(_NAME "opencensus_${NAME}")
    add_executable(${_NAME} ${SRC})
    prepend_opencensus(DEPS "${ARGN}")
    target_link_libraries(${_NAME} "${DEPS}" gmock gtest_main)
    add_test(NAME ${_NAME} COMMAND ${_NAME})
  endif()
endfunction()

# Helper function like bazel's cc_benchmark. Usage:
#
# opencensus_benchmark(trace_some_benchmark internal/some_benchmark.cc dep1
# dep2...)
function(opencensus_benchmark NAME SRC)
  if(BUILD_TESTING)
    set(_NAME "opencensus_${NAME}")
    add_executable(${_NAME} ${SRC})
    prepend_opencensus(DEPS "${ARGN}")
    target_link_libraries(${_NAME} "${DEPS}" benchmark)
  endif()
endfunction()

include(GNUInstallDirs)

#
# install( TARGETS PUBLIC_HEADERS DESTINATION foo ) does not work well when we
# declare opencensus_lib( libfoo PUBLIC HDRS bar/baz.h  SRCS bar/bar.cc ) it
# will generate   foo/baz.h   not foo/bar/baz.hh
#
# install_headers_with_subdirectories( PUBLIC_HEADERS item1 item2 ..
# INSTALL_FOLDER dir EXPORT export_name )
#
function(install_headers_with_subdirectories)
  set(options "")
  set(singleValued "INSTALL_FOLDER")
  set(multiValued "PUBLIC_HEADER")

  cmake_parse_arguments(ARG "${options}" "${singleValued}" "${multiValued}"
                        ${ARGN})

  foreach(header ${ARG_PUBLIC_HEADER})

    get_filename_component(dir ${header} DIRECTORY)

    install(FILES ${header} DESTINATION "${ARG_INSTALL_FOLDER}/${dir}")

  endforeach()

endfunction(install_headers_with_subdirectories)

# Helper function like bazel's cc_library.  Libraries are namespaced as
# opencensus_* and public libraries are also aliased as opencensus-cpp::*.
function(opencensus_lib NAME)
  cmake_parse_arguments(ARG "PUBLIC;PRIVATE" "" "HDRS;SRCS;DEPS" ${ARGN})
  set(_NAME "opencensus_${NAME}")
  prepend_opencensus(ARG_DEPS "${ARG_DEPS}")

  string(REPLACE "${PROJECT_SOURCE_DIR}/" "" _current_dir_relative_path
                 "${CMAKE_CURRENT_LIST_DIR}")

  if(ARG_SRCS)
    add_library(${_NAME} ${ARG_SRCS})
    target_link_libraries(${_NAME} PUBLIC ${ARG_DEPS})
    target_include_directories(
      ${_NAME} PUBLIC $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}>
                      $<INSTALL_INTERFACE:include>)
  else()
    add_library(${_NAME} INTERFACE)
    target_link_libraries(${_NAME} INTERFACE ${ARG_DEPS})
    target_include_directories(
      ${_NAME} INTERFACE $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}>
                         $<INSTALL_INTERFACE:include>)
  endif()
  if(ARG_PUBLIC)
    add_library(${PROJECT_NAME}::${NAME} ALIAS ${_NAME})

    if(ARG_HDRS)
      # this will install them set_target_properties( ${_NAME} PROPERTIES
      # PUBLIC_HEADER "${ARG_HDRS}" )
      install_headers_with_subdirectories(
        PUBLIC_HEADER ${ARG_HDRS} INSTALL_FOLDER
        "${CMAKE_INSTALL_INCLUDEDIR}/${_current_dir_relative_path}")
    endif()

    install(
      TARGETS ${_NAME}
      EXPORT opencensus-cpp-targets
      RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}"
      LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}"
      ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}" # PUBLIC_HEADER DESTINATION
              # "${CMAKE_INSTALL_INCLUDEDIR}/${_current_dir_relative_path}"
    )
  elseif(ARG_PRIVATE)
    # what we really wanted to do, if linking private static libraries into
    # public ones worked without having to export the private one...
  else()

    if(ARG_HDRS)
      # I think we have API problems whereby the internal includes are required
      # by clients... Comment out this line if it is not the case...
      # set_target_properties( ${_NAME} PROPERTIES PRIVATE_HEADER "${ARG_HDRS}"
      # )
      install_headers_with_subdirectories(
        PUBLIC_HEADER ${ARG_HDRS} INSTALL_FOLDER
        "${CMAKE_INSTALL_INCLUDEDIR}/${_current_dir_relative_path}")
    endif()

    # fight export bug ? I don't want these installed, I don't want the
    # associated headers installed I want them as depedencies to public static
    # libraries that aggregate them....
    install(
      TARGETS ${_NAME}
      EXPORT opencensus-cpp-targets
      RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}"
      LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}"
      ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}" # PUBLIC_HEADER DESTINATION
              # "${CMAKE_INSTALL_INCLUDEDIR}/${_current_dir_relative_path}"
    )

  endif()
endfunction()

# Helper function for fuzzing. Usage:
#
# opencensus_fuzzer(trace_some_fuzzer internal/some_fuzzer.cc dep1 dep2...)
function(opencensus_fuzzer NAME SRC)
  if(FUZZER)
    set(_NAME "opencensus_${NAME}")
    add_executable(${_NAME} ${SRC})
    prepend_opencensus(DEPS "${ARGN}")
    target_link_libraries(${_NAME} "${DEPS}" ${FUZZER})
    target_compile_options(${_NAME} PRIVATE ${FUZZER})
  endif()
endfunction()