Support to build dpi-specific apk variants.

In unbundled apps_only build, in addition to the base apk, you can also
build the dpi-specific apk variants, with:
LOCAL_DPI_VARIANTS := <a list of dpi names>

Previously user needs to include $(BUILD_PACKAGE) repeatedly with the
same package definition except dpi flags.
With this change, all the dpi-specific apk variants share the base apk's
compiled Java code and only diverge at the point we add resources/assets
to the apk.
Also we set up variables/targets/rules in a way those dpi-specific apks
appear to be independent apks to the users, for example, you can pass
"AppName_<dpi_name>" to tapas, and AppName_<dpi_name>.apk lives in its
own intermediate directory.

Bug: 18388705
Change-Id: I2ba4972ea7d1f796352fab2407888f996781ae44

2 files changed, 80 insertions, 0 deletions

diff --git a/core/dpi_specific_apk.mk b/core/dpi_specific_apk.mk
new file mode 100644
index 0000000..aad4713
--- /dev/null
+++ b/core/dpi_specific_apk.mk
@@ -0,0 +1,70 @@
+# Set up rules to build dpi-specific apk, with whatever else from the base apk.
+# Input variable: my_dpi, and all other variables set up in package_internal.mk.
+#
+
+dpi_apk_name := $(LOCAL_MODULE)_$(my_dpi)
+dpi_intermediate := $(call intermediates-dir-for,APPS,$(dpi_apk_name))
+built_dpi_apk := $(dpi_intermediate)/package.apk
+
+# Set up all the target-specific variables.
+$(built_dpi_apk): PRIVATE_MODULE := $(dpi_apk_name)
+$(built_dpi_apk): PRIVATE_AAPT_FLAGS := $(LOCAL_AAPT_FLAGS) $(PRODUCT_AAPT_FLAGS)
+# Clear PRIVATE_PRODUCT_AAPT_CONFIG to include everything by default.
+$(built_dpi_apk): PRIVATE_PRODUCT_AAPT_CONFIG :=
+$(built_dpi_apk): PRIVATE_PRODUCT_AAPT_PREF_CONFIG := $(my_dpi)
+$(built_dpi_apk): PRIVATE_ANDROID_MANIFEST := $(full_android_manifest)
+$(built_dpi_apk): PRIVATE_RESOURCE_DIR := $(LOCAL_RESOURCE_DIR)
+$(built_dpi_apk): PRIVATE_ASSET_DIR := $(LOCAL_ASSET_DIR)
+$(built_dpi_apk): PRIVATE_AAPT_INCLUDES := $(all_library_res_package_exports)
+ifneq (,$(filter-out current system_current, $(LOCAL_SDK_VERSION)))
+$(built_dpi_apk): PRIVATE_DEFAULT_APP_TARGET_SDK := $(LOCAL_SDK_VERSION)
+else
+$(built_dpi_apk): PRIVATE_DEFAULT_APP_TARGET_SDK := $(DEFAULT_APP_TARGET_SDK)
+endif
+$(built_dpi_apk): PRIVATE_MANIFEST_PACKAGE_NAME := $(LOCAL_MANIFEST_PACKAGE_NAME)
+$(built_dpi_apk): PRIVATE_MANIFEST_INSTRUMENTATION_FOR := $(LOCAL_INSTRUMENTATION_FOR)
+$(built_dpi_apk): PRIVATE_JNI_SHARED_LIBRARIES := $(jni_shared_libraries_with_abis)
+$(built_dpi_apk): PRIVATE_JNI_SHARED_LIBRARIES_ABI := $(jni_shared_libraries_abis)
+$(built_dpi_apk): PRIVATE_DEX_FILE := $(built_dex)
+# Note that PRIVATE_CLASS_INTERMEDIATES_DIR points to the base apk's intermediate dir.
+$(built_dpi_apk): PRIVATE_CLASS_INTERMEDIATES_DIR := $(intermediates)/classes
+$(built_dpi_apk): PRIVATE_EXTRA_JAR_ARGS := $(extra_jar_args)
+$(built_dpi_apk): PRIVATE_PRIVATE_KEY := $(private_key)
+$(built_dpi_apk): PRIVATE_CERTIFICATE := $(certificate)
+$(built_dpi_apk): PRIVATE_ADDITIONAL_CERTIFICATES := $(foreach c,\
+    $(LOCAL_ADDITIONAL_CERTIFICATES), $(c).x509.pem $(c).pk8)
+
+# Set up dependenncies and the build recipe.
+$(built_dpi_apk) : $(R_file_stamp)
+$(built_dpi_apk) : $(all_library_res_package_export_deps)
+$(built_dpi_apk) : $(built_dex)
+$(built_dpi_apk) : $(private_key) $(certificate) $(SIGNAPK_JAR)
+$(built_dpi_apk) : $(AAPT) | $(ZIPALIGN)
+$(built_dpi_apk) : $(all_res_assets) $(jni_shared_libraries) $(full_android_manifest)
+	@echo "target Package: $(PRIVATE_MODULE) ($@)"
+	$(create-empty-package)
+	$(add-assets-to-package)
+ifneq ($(jni_shared_libraries),)
+	$(add-jni-shared-libs-to-package)
+endif
+ifneq ($(full_classes_jar),)
+	$(add-dex-to-package)
+endif
+	$(add-carried-java-resources)
+ifneq ($(extra_jar_args),)
+	$(add-java-resources-to-package)
+endif
+	$(sign-package)
+	$(align-package)
+
+# Set up global variables to register this apk to the higher-level dependency graph.
+ALL_MODULES += $(dpi_apk_name)
+ALL_MODULES.$(dpi_apk_name).CLASS := APPS
+ALL_MODULES.$(dpi_apk_name).BUILT := $(built_dpi_apk)
+PACKAGES := $(PACKAGES) $(dpi_apk_name)
+PACKAGES.$(dpi_apk_name).PRIVATE_KEY := $(private_key)
+PACKAGES.$(dpi_apk_name).CERTIFICATE := $(certificate)
+
+# Phony targets used by "apps_only".
+.PHONY: $(dpi_apk_name)
+$(dpi_apk_name) : $(built_dpi_apk)
diff --git a/core/package_internal.mk b/core/package_internal.mk
index bb458d4..933b32f 100644
--- a/core/package_internal.mk
+++ b/core/package_internal.mk
@@ -407,6 +407,16 @@ endif
 	$(align-package)
 
 ###############################
+## Build dpi-specific apks, if it's apps_only build.
+ifdef TARGET_BUILD_APPS
+ifdef LOCAL_DPI_VARIANTS
+$(foreach d, $(LOCAL_DPI_VARIANTS), \
+  $(eval my_dpi := $(d)) \
+  $(eval include $(BUILD_SYSTEM)/dpi_specific_apk.mk))
+endif
+endif
+
+###############################
 ## Rule to build the odex file
 ifdef LOCAL_DEX_PREOPT
 $(built_odex): PRIVATE_DEX_FILE := $(built_dex)