Introduce BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES

If BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES has a numeric value,
it replaces "current" or "system_current" with the version which
the flag indicates.

Bug: 163009188
Test: BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES=29 m, and then check if every vendor
java module's sdk_version is 29 if its sdk_version was current.

Change-Id: I8c7cf21563b984b8e9ef398192031b1f66d96494
diff --git a/core/base_rules.mk b/core/base_rules.mk
index ddf736b..a0b1761 100644
--- a/core/base_rules.mk
+++ b/core/base_rules.mk
@@ -115,6 +115,7 @@
 
 include $(BUILD_SYSTEM)/local_vndk.mk
 include $(BUILD_SYSTEM)/local_systemsdk.mk
+include $(BUILD_SYSTEM)/local_current_sdk.mk
 
 my_module_tags := $(LOCAL_MODULE_TAGS)
 ifeq ($(my_host_cross),true)
diff --git a/core/config.mk b/core/config.mk
index 57296d8..a286769 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -720,6 +720,16 @@
   endif
 endif
 
+ifndef BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES
+  BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES := current
+else
+  ifdef PRODUCT_SHIPPING_API_LEVEL
+    ifneq ($(call math_lt,$(BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES),$(PRODUCT_SHIPPING_API_LEVEL)),)
+      $(error BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES ($(BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES)) must be greater than or equal to PRODUCT_SHIPPING_API_LEVEL ($(PRODUCT_SHIPPING_API_LEVEL)))
+    endif
+  endif
+endif
+.KATI_READONLY := BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES
 
 ifdef PRODUCT_SHIPPING_API_LEVEL
   ifneq ($(call numbers_less_than,$(PRODUCT_SHIPPING_API_LEVEL),$(BOARD_SYSTEMSDK_VERSIONS)),)
diff --git a/core/local_current_sdk.mk b/core/local_current_sdk.mk
new file mode 100644
index 0000000..ea7da8a
--- /dev/null
+++ b/core/local_current_sdk.mk
@@ -0,0 +1,26 @@
+#
+# Copyright (C) 2020 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+ifdef BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES
+  ifneq (current,$(BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES))
+    ifneq (,$(filter true,$(LOCAL_VENDOR_MODULE) $(LOCAL_ODM_MODULE) $(LOCAL_PROPRIETARY_MODULE)))
+      ifeq (current,$(LOCAL_SDK_VERSION))
+        LOCAL_SDK_VERSION := $(BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES)
+      else ifeq (system_current,$(LOCAL_SDK_VERSION))
+        LOCAL_SDK_VERSION := system_$(BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES)
+      endif
+    endif
+  endif
+endif
diff --git a/core/soong_config.mk b/core/soong_config.mk
index 4731250..ad2e816 100644
--- a/core/soong_config.mk
+++ b/core/soong_config.mk
@@ -210,6 +210,7 @@
 $(call end_json_map)
 
 $(call add_json_bool, EnforceProductPartitionInterface,  $(PRODUCT_ENFORCE_PRODUCT_PARTITION_INTERFACE))
+$(call add_json_str,  DeviceCurrentApiLevelForVendorModules,  $(BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES))
 
 $(call add_json_bool, InstallExtraFlattenedApexes, $(PRODUCT_INSTALL_EXTRA_FLATTENED_APEXES))