ProtobufDownloader.cmake

macro(protobuf_extract PROTOBUF_ARCHIVE VERSION_STRING PROTOBUF_SOURCE_PATH)

  if(EXISTS "${PROTOBUF_ARCHIVE}")
    set(${PROTOBUF_SOURCE_PATH} "${PROJECT_BINARY_DIR}/protobuf-${VERSION_STRING}")
    message(STATUS "Extracting Protobuf sources to '${${PROTOBUF_SOURCE_PATH}}'...")
    execute_process(
      COMMAND ${CMAKE_COMMAND} -E tar xzf "${PROTOBUF_ARCHIVE}"
      WORKING_DIRECTORY "${PROJECT_BINARY_DIR}")
  endif()

endmacro(protobuf_extract)

macro(protobuf_download VERSION_STRING PROTOBUF_ARCHIVE)

  set(PROTOBUF_ARCHIVE_URL
    "http://protobuf.googlecode.com/files/protobuf-${VERSION_STRING}.tar.gz")

  message(STATUS "Downloading Protobuf version ${VERSION_STRING} from '${PROTOBUF_ARCHIVE_URL}'...")

  set(PROTOBUF_DOWNLOAD_PATH
    "${PROJECT_BINARY_DIR}/protobuf-${VERSION_STRING}.tar.gz")

  file(DOWNLOAD "${PROTOBUF_ARCHIVE_URL}" "${PROTOBUF_DOWNLOAD_PATH}"
     STATUS status)

  list(GET status 0 error_code)

  if(error_code)
    file(REMOVE "${PROTOBUF_DOWNLOAD_PATH}")
    list(GET status 1 error_msg)
    message(FATAL_ERROR
      "Failed to download Protobuf source archive '${PROTOBUF_ARCHIVE_URL}': ${error_msg}")
  else()
    set(${PROTOBUF_ARCHIVE} "${PROTOBUF_DOWNLOAD_PATH}")
    message(STATUS "Successfully downloaded Protobuf version ${VERSION_STRING}.")
  endif()

endmacro(protobuf_download)

macro(protobuf_download_and_extract VERSION_STRING PROTOBUF_SOURCE_PATH)
  protobuf_download(${VERSION_STRING} PROTOBUF_ARCHIVE)
  protobuf_extract(${PROTOBUF_ARCHIVE} ${VERSION_STRING} ${PROTOBUF_SOURCE_PATH})
endmacro(protobuf_download_and_extract)