Combine aconfig cache files into per-partition dumps.

Bug: 283910439
Test: manual validation of outputs, soong unit tests
Change-Id: I5f7dc16ee42c3722dc66ffe964ed20479eea1e15
diff --git a/core/packaging/flags.mk b/core/packaging/flags.mk
new file mode 100644
index 0000000..4b692be
--- /dev/null
+++ b/core/packaging/flags.mk
@@ -0,0 +1,122 @@
+# Copyright (C) 2023 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 is included by build/make/core/Makefile, and contains the logic for
+# the combined flags files.
+#
+
+# TODO: Should we do all of the images in $(IMAGES_TO_BUILD)?
+_FLAG_PARTITIONS := product system system_ext vendor
+
+
+# -----------------------------------------------------------------
+# Release Config Flags
+
+# Create a summary file of build flags for each partition
+# $(1): built build flags json file
+# $(2): installed build flags json file
+# $(3): flag names
+define generate-partition-build-flag-file
+$(eval $(strip $(1)): PRIVATE_OUT := $(strip $(1)))
+$(eval $(strip $(1)): PRIVATE_FLAG_NAMES := $(strip $(3)))
+$(strip $(1)):
+	mkdir -p $$(dir $$(PRIVATE_OUT))
+	echo '{' > $$(PRIVATE_OUT)
+	echo '"flags": [' >> $$(PRIVATE_OUT)
+	$$(foreach flag, $$(PRIVATE_FLAG_NAMES), \
+		( \
+			printf '  { "name": "%s", "value": "%s", ' \
+					'$$(flag)' \
+					'$$(_ALL_RELEASE_FLAGS.$$(flag).VALUE)' \
+					; \
+			printf '"set": "%s", "default": "%s", "declared": "%s" }' \
+					'$$(_ALL_RELEASE_FLAGS.$$(flag).SET_IN)' \
+					'$$(_ALL_RELEASE_FLAGS.$$(flag).DEFAULT)' \
+					'$$(_ALL_RELEASE_FLAGS.$$(flag).DECLARED_IN)' \
+					; \
+			printf '$$(if $$(filter $$(lastword $$(PRIVATE_FLAG_NAMES)),$$(flag)),,$$(comma))\n' ; \
+		) >> $$(PRIVATE_OUT) ; \
+	)
+	echo "]" >> $$(PRIVATE_OUT)
+	echo "}" >> $$(PRIVATE_OUT)
+$(call copy-one-file, $(1), $(2))
+endef
+
+$(foreach partition, $(_FLAG_PARTITIONS), \
+	$(eval build_flag_summaries.$(partition) := $(PRODUCT_OUT)/$(partition)/etc/build_flags.json) \
+	$(eval $(call generate-partition-build-flag-file, \
+				$(TARGET_OUT_FLAGS)/$(partition)/build_flags.json, \
+				$(build_flag_summaries.$(partition)), \
+				$(_ALL_RELEASE_FLAGS.PARTITIONS.$(partition)) \
+			) \
+	) \
+)
+
+
+# -----------------------------------------------------------------
+# Aconfig Flags
+
+# Create a summary file of build flags for each partition
+# $(1): built aconfig flags textprot file (out)
+# $(2): installed aconfig flags textprot file (out)
+# $(3): input aconfig files for the partition (in)
+define generate-partition-aconfig-flag-file
+$(eval $(strip $(1)): PRIVATE_OUT := $(strip $(1)))
+$(eval $(strip $(1)): PRIVATE_IN := $(strip $(3)))
+$(strip $(1)): $(ACONFIG)
+	mkdir -p $$(dir $$(PRIVATE_OUT))
+	$$(if $$(PRIVATE_IN), \
+		$$(ACONFIG) dump --format textproto --out $$(PRIVATE_OUT) \
+			$$(addprefix --cache ,$$(PRIVATE_IN)), \
+		echo "# No aconfig flags" > $$(PRIVATE_OUT) \
+	)
+$(call copy-one-file, $(1), $(2))
+endef
+
+
+$(foreach partition, $(_FLAG_PARTITIONS), \
+	$(eval aconfig_flag_summaries.$(partition) := $(PRODUCT_OUT)/$(partition)/etc/aconfig_flags.textproto) \
+	$(eval $(call generate-partition-aconfig-flag-file, \
+				$(TARGET_OUT_FLAGS)/$(partition)/aconfig_flags.textproto, \
+				$(aconfig_flag_summaries.$(partition)), \
+				$(sort $(foreach m,$(call register-names-for-partition, $(partition)), \
+					$(ALL_MODULES.$(m).ACONFIG_FILES) \
+				)) \
+	)) \
+)
+
+
+# -----------------------------------------------------------------
+# Install the ones we need for the configured product
+required_flags_files := \
+		$(sort $(foreach partition, $(filter $(IMAGES_TO_BUILD), $(_FLAG_PARTITIONS)), \
+			$(build_flag_summaries.$(partition)) \
+			$(aconfig_flag_summaries.$(partition)) \
+		))
+
+ALL_DEFAULT_INSTALLED_MODULES += $(required_flags_files)
+
+# TODO: Remove
+.PHONY: flag-files
+flag-files: $(required_flags_files)
+
+
+# Clean up
+required_flags_files:=
+$(foreach partition, $(_FLAG_PARTITIONS), \
+	$(eval build_flag_summaries.$(partition):=) \
+	$(eval aconfig_flag_summaries.$(partition):=) \
+)
+