Merge hidden API metadata into a single CSV file.

Add a python script to merge the CSV files, dealing with the fact that the
source columns may differ due to the annotation properties present in the
source.

Add this new file and the existing greylist.txt files as dependencies of
the 'dist' target, so that they appear as artifacts on the build server.
This allows them to be processed later by reading them from the build
server.

Test: m out/target/common/obj/PACKAGING/hiddenapi-greylist.csv
Bug: 117314178
Change-Id: Ib9e5da90e4c32333a3f4f02ee7f159f77086ae5e
diff --git a/Android.mk b/Android.mk
index d333074..82a661a 100644
--- a/Android.mk
+++ b/Android.mk
@@ -111,6 +111,17 @@
 	$(call commit-change-for-toc,$(INTERNAL_PLATFORM_HIDDENAPI_DARK_GREYLIST))
 	$(call commit-change-for-toc,$(INTERNAL_PLATFORM_HIDDENAPI_BLACKLIST))
 
+$(INTERNAL_PLATFORM_HIDDENAPI_GREYLIST_METADATA): \
+    frameworks/base/tools/hiddenapi/merge_csv.py \
+    $(PRIVATE_METADATA_INPUTS)
+	frameworks/base/tools/hiddenapi/merge_csv.py $(PRIVATE_METADATA_INPUTS) > $@
+
+$(call dist-for-goals,droidcore,$(INTERNAL_PLATFORM_HIDDENAPI_WHITELIST))
+$(call dist-for-goals,droidcore,$(INTERNAL_PLATFORM_HIDDENAPI_LIGHT_GREYLIST))
+$(call dist-for-goals,droidcore,$(INTERNAL_PLATFORM_HIDDENAPI_DARK_GREYLIST))
+$(call dist-for-goals,droidcore,$(INTERNAL_PLATFORM_HIDDENAPI_BLACKLIST))
+$(call dist-for-goals,droidcore,$(INTERNAL_PLATFORM_HIDDENAPI_GREYLIST_METADATA))
+
 # Include subdirectory makefiles
 # ============================================================
 
diff --git a/tools/hiddenapi/merge_csv.py b/tools/hiddenapi/merge_csv.py
new file mode 100755
index 0000000..48c0755
--- /dev/null
+++ b/tools/hiddenapi/merge_csv.py
@@ -0,0 +1,40 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2018 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.
+"""
+Merge mutliple CSV files, possibly with different columns, writing to stdout.
+"""
+
+import csv
+import sys
+
+csv_readers = [
+    csv.DictReader(open(csv_file, 'rb'), delimiter=',', quotechar='|')
+    for csv_file in sys.argv[1:]
+]
+
+# Build union of all columns from source files:
+headers = set()
+for reader in csv_readers:
+  headers = headers.union(reader.fieldnames)
+
+# Concatenate all files to output:
+out = csv.DictWriter(sys.stdout, delimiter=',', quotechar='|', fieldnames = sorted(headers))
+out.writeheader()
+for reader in csv_readers:
+  for row in reader:
+    out.writerow(row)
+
+