1# Copyright (c) 2022, Google, Inc. All rights reserved
2#
3# Licensed under the Apache License, Version 2.0 (the "License");
4# you may not use this file except in compliance with the License.
5# You may obtain a copy of the License at
6#
7#      http://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12# See the License for the specific language governing permissions and
13# limitations under the License.
14#
15
16# Invoke a protoc command with a custom plugin for protobuf-driven code
17# generation and build a library from the generated sources.
18#
19# args:
20# MODULE : module name (required)
21# MODULE_PROTOC_PLUGIN: path to a python protoc plugin (required)
22# MODULE_PROTOC_PLUGIN_FLAGS: optional flags for the custom plugin
23#                             shared via env variable
24# MODULE_PROTOS: list of PROTO files
25# MODULE_PROTO_PACKAGE: a path that matches the directory structure of
26#                       the PROTO package utilized in the module.
27
28PROTOC_TOOL ?= $(firstword $(wildcard out/host/linux-x86/bin/aprotoc prebuilts/libprotobuf/bin/protoc))
29
30ifeq ($(PROTOC_TOOL),)
31$(error No PROTOC_TOOL. Please build the aprotoc or checkout with trusty manifest)
32endif
33
34ifeq ($(MODULE_PROTOC_PLUGIN),)
35$(error No MODULE_PROTOC_PLUGIN provided for $(MODULE))
36endif
37
38# WARNING: this implies all sources are under the same package.
39# TODO(b/259511922): support multiple packages.
40MODULE_SRCS := $(call TOBUILDDIR,$(patsubst %.proto,%.c,$(MODULE_PROTOS)))
41MODULE_PROTO_OUT_DIR := $(sort $(dir $(subst $(MODULE_PROTO_PACKAGE),,$(MODULE_SRCS))))
42
43# TODO: support multiple, disparate packages;
44# the output directory for the tool should be at the root of
45# the package path.
46$(MODULE_SRCS): PROTOC_TOOL := $(PROTOC_TOOL)
47$(MODULE_SRCS): MODULE_PROTOC_PLUGIN := $(MODULE_PROTOC_PLUGIN)
48$(MODULE_SRCS): MODULE_PROTOC_PLUGIN_FLAGS := $(MODULE_PROTOC_PLUGIN_FLAGS)
49$(MODULE_SRCS): MODULE_PROTO_PACKAGE := $(MODULE_PROTO_PACKAGE)
50$(MODULE_SRCS): MODULE_PROTO_OUT_DIR := $(MODULE_PROTO_OUT_DIR)
51$(MODULE_SRCS): $(BUILDDIR)/%.c: %.proto $(MODULE_PROTOC_PLUGIN)
52	@$(MKDIR)
53	@echo generating $@ from PROTO
54	$(NOECHO)$(PROTOC_TOOL) \
55		--plugin=protoc-gen-custom-plugin=$(MODULE_PROTOC_PLUGIN) \
56		--custom-plugin_out=$(MODULE_PROTO_OUT_DIR) \
57		--custom-plugin_opt=pkg:$(MODULE_PROTO_PACKAGE),$(MODULE_PROTOC_PLUGIN_FLAGS) \
58		$<
59
60MODULE_EXPORT_INCLUDES += $(MODULE_PROTO_OUT_DIR)/include
61
62# Ensure that all auto-generated code, including headers, is
63# emitted before downstream dependencies
64MODULE_EXPORT_SRCDEPS += $(MODULE_SRCS)
65
66# Build the PROTO module into a library
67include make/library.mk
68
69MODULE_PROTOS :=
70PROTOC_TOOL :=
71MODULE_PROTO_OUT_DIR :=
72MODULE_PROTOC_PLUGIN :=
73MODULE_PROTOC_PLUGIN_FLAGS :=
74MODULE_PROTO_PACKAGE :=
75