Clean common intermediate files if overlay changed

This change cleans the packages' intermediate files if their overlays
changed between incremental builds.
If two builds have different overlay, they will have different R
classes, and so the jar files in the common intermediate dirs can
not be shared. Therefore incremental build can't be applied.

This change detects the overlay changes on package's base.
If a package's overlay is different from the previous build, its common
intermediate dir is nuked.
This makes broader incremental builds possible.

Change-Id: I368610ebbbbc85a80f9aecd714ab22cd78da7f12

core/main.mk

@@ -466,8 +466,12 @@ subdir_makefiles := \
 	$(shell build/tools/findleaves.py --prune=out --prune=.repo --prune=.git $(subdirs) Android.mk)
 
 include $(subdir_makefiles)
+
 endif # ONE_SHOT_MAKEFILE
 
+# Now with all Android.mks loaded we can do post cleaning steps.
+include $(BUILD_SYSTEM)/post_clean.mk
+
 ifeq ($(stash_product_vars),true)
   $(call assert-product-vars, __STASHED)
 endif

core/package.mk

@@ -94,12 +94,14 @@ endif
 ifeq (,$(LOCAL_RESOURCE_DIR))
   LOCAL_RESOURCE_DIR := $(LOCAL_PATH)/res
 endif
-LOCAL_RESOURCE_DIR := \
-  $(wildcard $(foreach dir, $(PRODUCT_PACKAGE_OVERLAYS), \
-    $(addprefix $(dir)/, $(LOCAL_RESOURCE_DIR)))) \
-  $(wildcard $(foreach dir, $(DEVICE_PACKAGE_OVERLAYS), \
-    $(addprefix $(dir)/, $(LOCAL_RESOURCE_DIR)))) \
-  $(LOCAL_RESOURCE_DIR)
+
+package_resource_overlays := $(strip \
+    $(wildcard $(foreach dir, $(PRODUCT_PACKAGE_OVERLAYS), \
+      $(addprefix $(dir)/, $(LOCAL_RESOURCE_DIR)))) \
+    $(wildcard $(foreach dir, $(DEVICE_PACKAGE_OVERLAYS), \
+      $(addprefix $(dir)/, $(LOCAL_RESOURCE_DIR)))))
+
+LOCAL_RESOURCE_DIR := $(package_resource_overlays) $(LOCAL_RESOURCE_DIR)
 
 all_assets := $(call find-subdir-assets,$(LOCAL_ASSET_DIR))
 all_assets := $(addprefix $(LOCAL_ASSET_DIR)/,$(patsubst assets/%,%,$(all_assets)))
@@ -399,6 +401,9 @@ endif
 # Save information about this package
 PACKAGES.$(LOCAL_PACKAGE_NAME).OVERRIDES := $(strip $(LOCAL_OVERRIDES_PACKAGES))
 PACKAGES.$(LOCAL_PACKAGE_NAME).RESOURCE_FILES := $(all_resources)
+ifdef package_resource_overlays
+PACKAGES.$(LOCAL_PACKAGE_NAME).RESOURCE_OVERLAYS := $(package_resource_overlays)
+endif
 
 PACKAGES := $(PACKAGES) $(LOCAL_PACKAGE_NAME)
 

core/post_clean.mk

@@ -0,0 +1,53 @@
+# Copyright (C) 2012 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.
+
+# Clean steps that need global knowledge of individual modules.
+# This file must be included after all Android.mks have been loaded.
+
+# Checks the current build configurations against the previous build,
+# clean artifacts in TARGET_COMMON_OUT_ROOT if necessary.
+# If a package's resource overlay has been changed, its R class needs to be
+# regenerated.
+previous_package_overlay_config := $(TARGET_OUT_COMMON_INTERMEDIATES)/APPS/previous_overlays.txt
+current_package_overlay_config := $(TARGET_OUT_COMMON_INTERMEDIATES)/APPS/current_overlays.txt
+current_all_packages_config := $(dir $(current_package_overlay_config))current_packages.txt
+
+$(shell rm -rf $(current_package_overlay_config) \
+    && mkdir -p $(dir $(current_package_overlay_config)) \
+    && touch $(current_package_overlay_config))
+$(shell echo '$(PACKAGES)' > $(current_all_packages_config))
+$(foreach p, $(PACKAGES), $(if $(PACKAGES.$(p).RESOURCE_OVERLAYS), \
+  $(shell echo '$(p)' '$(PACKAGES.$(p).RESOURCE_OVERLAYS)' >> $(current_package_overlay_config))))
+
+ifneq (,$(wildcard $(previous_package_overlay_config)))
+packages_overlay_changed := $(shell build/tools/diff_package_overlays.py \
+    $(current_all_packages_config) $(current_package_overlay_config) \
+    $(previous_package_overlay_config))
+ifneq (,$(packages_overlay_changed))
+overlay_cleanup_cmd := $(strip rm -rf $(foreach p, $(packages_overlay_changed),\
+    $(TARGET_OUT_COMMON_INTERMEDIATES)/APPS/$(p)_intermediates))
+$(info *** Overlay change detected, clean shared intermediate files...)
+$(info *** $(overlay_cleanup_cmd))
+$(shell $(overlay_cleanup_cmd))
+overlay_cleanup_cmd :=
+endif
+packages_overlay_changed :=
+endif
+
+# Now current becomes previous.
+$(shell mv -f $(current_package_overlay_config) $(previous_package_overlay_config))
+
+previous_package_overlay_config :=
+current_package_overlay_config :=
+current_all_packages_config :=

tools/diff_package_overlays.py

@@ -0,0 +1,91 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2012 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.
+
+"""
+Prints to stdout the package names that have overlay changes between
+current_overlays.txt and previous_overlays.txt.
+
+Usage: diff_package_overlays.py <current_packages.txt> <current_overlays.txt> <previous_overlays.txt>
+current_packages.txt contains all package names separated by space in the current build.
+This script modfies current_packages.txt if necessary: if there is a package in
+previous_overlays.txt but absent from current_packages.txt, we copy that line
+from previous_overlays.txt over to current_packages.txt. Usually that means we
+just don't care that package in the current build (for example we are switching
+from a full build to a partial build with mm/mmm), and we should carry on the
+previous overlay config so current_overlays.txt always reflects the current
+status of the entire tree.
+
+Format of current_overlays.txt and previous_overlays.txt:
+  <package_name> <resource_overlay> [resource_overlay ...]
+  <package_name> <resource_overlay> [resource_overlay ...]
+  ...
+"""
+
+import sys
+
+def main(argv):
+  if len(argv) != 4:
+    print >> sys.stderr, __doc__
+    sys.exit(1)
+
+  f = open(argv[1])
+  all_packages = set(f.read().split())
+  f.close()
+
+  def load_overlay_config(filename):
+    f = open(filename)
+    result = {}
+    for line in f:
+      line = line.strip()
+      if not line or line.startswith("#"):
+        continue
+      words = line.split()
+      result[words[0]] = " ".join(words[1:])
+    f.close()
+    return result
+
+  current_overlays = load_overlay_config(argv[2])
+  previous_overlays = load_overlay_config(argv[3])
+
+  result = []
+  carryon = []
+  for p in current_overlays:
+    if p not in previous_overlays:
+      result.append(p)
+    elif current_overlays[p] != previous_overlays[p]:
+      result.append(p)
+  for p in previous_overlays:
+    if p not in current_overlays:
+      if p in all_packages:
+        # overlay changed
+        result.append(p)
+      else:
+        # we don't build p in the current build.
+        carryon.append(p)
+
+  # Add carryon to the current overlay config file.
+  if carryon:
+    f = open(argv[2], "a")
+    for p in carryon:
+      f.write(p + " " + previous_overlays[p] + "\n")
+    f.close()
+
+  # Print out the package names that have overlay change.
+  for r in result:
+    print r
+
+if __name__ == "__main__":
+  main(sys.argv)