| # |
| # Copyright (C) 2015 The Android Open Source Project |
| # |
| # 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. |
| # |
| |
| # This file provides a helper which loads the contents of a given file |
| # relative to a common root path. The helper ensures there is consistent |
| # path resolution for loading and error messaging for missing or empty |
| # files that are required. |
| # |
| # The primary usage of this file is for loading product-level configuration |
| # from plaintext files. An example usage in a makefile is: |
| # BRILLO_CRASH_SERVER := $(call cfgtree_get,brillo/crash_server,required) |
| # |
| # Note the use of an immediate assignment. If any other variable assignment is |
| # used, be sure to test that it resolves as and when expected. |
| # |
| # Populating the file is as simple as: |
| # cd $PRODUCT_DIR |
| # mkdir -p config/brillo |
| # echo https://some.server/handle/crash.cgi > config/brillo/crash_server |
| # |
| # Any lines beginning with '#' will be ignored, but if a '#' is required, it |
| # can be inserted by simply starting the line with a space which will be |
| # stripped off during the loading process. |
| # |
| # Note, there is no central mapping of variables to files. If any files will |
| # be used from different contexts, be sure to keep all users in sync. |
| # |
| # For any PRODUCT_* variable set using this mechanism, it is possible to |
| # verify a correct assignment by calling: |
| # |
| # m dump-products |
| # |
| |
| # Path to load from |
| CFGTREE_ROOT ?= $(LOCAL_PATH) |
| CFGTREE_PREFIX ?= config |
| CFGTREE_PATH := $(CFGTREE_ROOT)/$(CFGTREE_PREFIX) |
| |
| # Command to run to dump the file content. |
| CFGTREE_CMD ?= grep -v -e '^$(shell printf '\043')' |
| |
| # $(1) is the file to load from cfgtree |
| # |
| # Returns the output of $(CFGTREE_CMD) $(1)/$(2) if the file exists. |
| # Normally, this is all the text excluding lines starting with '#'. |
| # |
| define cfgtree-get |
| $(strip \ |
| $(if $(filter 0,$(words $(call cfgtree-get-if-exists,$(1)))),\ |
| $(error Required configuration file \ |
| $(CFGTREE_PREFIX)/$(1) is empty or missing.),\ |
| $(call cfgtree-get-if-exists,$(1)))\ |
| ) |
| endef |
| |
| define cfgtree-get-if-exists |
| $(strip $(shell $(CFGTREE_CMD) $(CFGTREE_PATH)/$(1) 2>/dev/null)) |
| endef |