Support to build static Java library with Android resource

Bug: 5714516

The rationale behind this change:
- the library is compiled into a jar file, but its R class is generated
  making the constant not constant (static, not final static) (aapt
  option --non-constant-id). Also the jar file does not contain the R
  class.
- this allows the integer value to not be inlined in the compiled
  class files. Note that this prevents using switch statements.
- the main project use this jar file as a normal static library: it will
  add all the class files except the R.class.
- the main project uses the library res folder as a resource
  folder with lower priority than the main project (basically the
  main project is an overlay. This is accomplished using aapt's
  --auto-add-overlay to handle resources only in the main project
  (which the normal overlay mechanism doesn't allow).
- the main project creates R classes in the main project's
  package but also in the library's package. This is done with
  aapt's --extra-packages which accept as many packages as
  needed, separated by a :.
- manifest merging is not done yet, so
  activities/services/permissions/etc... have to be manually declared in
  the main app.

To use a static library with Android resource in your app,
1. Add the library's resource dir to your app as an overlay:
LOCAL_RESOURCE_DIR := <app_resource_dir> <static_library_resource_dirs>
2. Set the proper aapt flags:
LOCAL_AAPT_FLAGS := <apps_own_flags> --auto-add-overlay \
  --extra-packages <lib1_package_name>:<lib2_package_name>:...

Change-Id: Ifb4d2300b952ea4aaee74da1bb0c6c72ea0698a3

3 files changed, 76 insertions, 0 deletions

diff --git a/core/definitions.mk b/core/definitions.mk
index e950d38..f16b4c9 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -1408,6 +1408,9 @@ endef
 
 # For a list of jar files, unzip them to a specified directory,
 # but make sure that no META-INF files come along for the ride.
+# We also remove any R.class/Manifest.class from the jar files;
+# R/Manifest class for the static Java libraries should be
+# re-generate in the app module instead.
 #
 # $(1): files to unzip
 # $(2): destination directory
@@ -1421,6 +1424,7 @@ define unzip-jar-files
     unzip -qo $$f -d $(2); \
     (cd $(2) && rm -rf META-INF); \
   done
+  $(hide) find $(2) -name 'R.class' -o -name 'R$$*.class' -o -name 'Manifest.class' -o -name 'Manifest$$*.class' | xargs rm -rf
 endef
 
 # Common definition to invoke javac on the host and target.
diff --git a/core/java_library.mk b/core/java_library.mk
index fa40c0e..904ef5f 100644
--- a/core/java_library.mk
+++ b/core/java_library.mk
@@ -14,9 +14,11 @@ ifneq (,$(LOCAL_ASSET_DIR))
 $(error $(LOCAL_PATH): Target java libraries may not set LOCAL_ASSET_DIR)
 endif
 
+ifneq (true,$(LOCAL_IS_STATIC_JAVA_LIBRARY))
 ifneq (,$(LOCAL_RESOURCE_DIR))
 $(error $(LOCAL_PATH): Target java libraries may not set LOCAL_RESOURCE_DIR)
 endif
+endif
 
 #xxx base_rules.mk looks at this
 all_res_assets :=
diff --git a/core/static_java_library.mk b/core/static_java_library.mk
index 93d770a..3a1925d 100644
--- a/core/static_java_library.mk
+++ b/core/static_java_library.mk
@@ -21,5 +21,75 @@
 
 LOCAL_UNINSTALLABLE_MODULE := true
 LOCAL_IS_STATIC_JAVA_LIBRARY := true
+
+# Hack to build static Java library with Android resource
+# See bug 5714516
+all_resources :=
+ifdef LOCAL_RESOURCE_DIR
+all_resources := $(strip \
+    $(foreach dir, $(LOCAL_RESOURCE_DIR), \
+      $(addprefix $(dir)/, \
+        $(patsubst res/%,%, \
+          $(call find-subdir-assets,$(dir)) \
+        ) \
+      ) \
+    ))
+endif
+
 include $(BUILD_SYSTEM)/java_library.mk
+
+ifneq (,$(all_resources))
+R_file_stamp := $(LOCAL_INTERMEDIATE_SOURCE_DIR)/R.stamp
+
+ifeq ($(strip $(LOCAL_MANIFEST_FILE)),)
+LOCAL_MANIFEST_FILE := AndroidManifest.xml
+endif
+full_android_manifest := $(LOCAL_PATH)/$(LOCAL_MANIFEST_FILE)
+
+framework_res_package_export :=
+framework_res_package_export_deps :=
+# Please refer to package.mk
+ifneq ($(LOCAL_NO_STANDARD_LIBRARIES),true)
+ifneq ($(filter-out current,$(LOCAL_SDK_RES_VERSION)),)
+framework_res_package_export := \
+    $(HISTORICAL_SDK_VERSIONS_ROOT)/$(LOCAL_SDK_RES_VERSION)/android.jar
+framework_res_package_export_deps := $(framework_res_package_export)
+else
+framework_res_package_export := \
+    $(call intermediates-dir-for,APPS,framework-res,,COMMON)/package-export.apk
+framework_res_package_export_deps := \
+    $(dir $(framework_res_package_export))src/R.stamp
+endif
+endif
+
+$(R_file_stamp): PRIVATE_MODULE := $(LOCAL_MODULE)
+# add --non-constant-id to prevent inlining constants.
+$(R_file_stamp): PRIVATE_AAPT_FLAGS := $(LOCAL_AAPT_FLAGS) --non-constant-id
+$(R_file_stamp): PRIVATE_SOURCE_INTERMEDIATES_DIR := $(LOCAL_INTERMEDIATE_SOURCE_DIR)
+$(R_file_stamp): PRIVATE_ANDROID_MANIFEST := $(full_android_manifest)
+$(R_file_stamp): PRIVATE_RESOURCE_PUBLICS_OUTPUT := $(intermediates.COMMON)/public_resources.xml
+$(R_file_stamp): PRIVATE_RESOURCE_DIR := $(LOCAL_RESOURCE_DIR)
+$(R_file_stamp): PRIVATE_AAPT_INCLUDES := $(framework_res_package_export)
+ifneq (,$(filter-out current, $(LOCAL_SDK_VERSION)))
+$(R_file_stamp): PRIVATE_DEFAULT_APP_TARGET_SDK := $(LOCAL_SDK_VERSION)
+else
+$(R_file_stamp): PRIVATE_DEFAULT_APP_TARGET_SDK := $(DEFAULT_APP_TARGET_SDK)
+endif
+$(R_file_stamp): PRIVATE_ASSET_DIR :=
+$(R_file_stamp): PRIVATE_PROGUARD_OPTIONS_FILE :=
+$(R_file_stamp): PRIVATE_MANIFEST_PACKAGE_NAME :=
+$(R_file_stamp): PRIVATE_MANIFEST_INSTRUMENTATION_FOR :=
+
+$(R_file_stamp) : $(all_resources) $(full_android_manifest) $(AAPT) $(framework_res_package_export_deps)
+	@echo "target R.java/Manifest.java: $(PRIVATE_MODULE) ($@)"
+	$(create-resource-java-files)
+	$(hide) find $(PRIVATE_SOURCE_INTERMEDIATES_DIR) -name R.java | xargs cat > $@
+
+$(LOCAL_BUILT_MODULE): $(R_file_stamp)
+ifneq ($(full_classes_jar),)
+$(full_classes_compiled_jar): $(R_file_stamp)
+endif
+
+endif  # $(all_resources) not empty
+
 LOCAL_IS_STATIC_JAVA_LIBRARY :=