| # Find the prefix from the `*Config.cmake` file being generated. |
| # |
| # When generating an installed `*Config.cmake` file, we often want to be able |
| # to refer to the ancestor directory which contains all the installed files. |
| # |
| # We want to do this without baking in an absolute path when the config file is |
| # generated, in order to allow for a "relocatable" binary distribution that |
| # doesn't need to know what path it ends up being installed at when it is |
| # built. |
| # |
| # The solution that we know the relative path that the config file will be at |
| # within that prefix, like `"${prefix_var}/lib/cmake/${project}"`, so we count |
| # the number of components in that path to figure out how many parent dirs we |
| # need to traverse from the location of the config file to get to the prefix |
| # dir. |
| # |
| # out_var: |
| # variable to set the "return value" of the function, which is the code to |
| # include in the config file under construction. |
| # |
| # prefix_var: |
| # Name of the variable to define in the returned code (not directory for the |
| # faller!) that will contain the prefix path. |
| # |
| # path_to_leave: |
| # Path from the prefix to the config file, a relative path which we wish to |
| # go up and out from to find the prefix directory. |
| function(find_prefix_from_config out_var prefix_var path_to_leave) |
| set(config_code |
| "# Compute the installation prefix from this LLVMConfig.cmake file location." |
| "get_filename_component(${prefix_var} \"\${CMAKE_CURRENT_LIST_FILE}\" PATH)") |
| # Construct the proper number of get_filename_component(... PATH) |
| # calls to compute the installation prefix. |
| string(REGEX REPLACE "/" ";" _count "${path_to_leave}") |
| foreach(p ${_count}) |
| list(APPEND config_code |
| "get_filename_component(${prefix_var} \"\${${prefix_var}}\" PATH)") |
| endforeach(p) |
| string(REPLACE ";" "\n" config_code "${config_code}") |
| set("${out_var}" "${config_code}" PARENT_SCOPE) |
| endfunction() |