Move hiddenapi tools used by build/soong from frameworks/base
Also, creates a python_binary_host module for generate_hiddenapi_lists
and uses that when constructing the build rule rather than using the
file directly.
Bug: 177317659
Test: m droid
Verified that hiddenapi files (both aggregated ones and for the
individual modules) are not affected by this change.
Change-Id: Ia11bb203ce5a74740d35f1b7e86716e15aad336e
diff --git a/scripts/hiddenapi/Android.bp b/scripts/hiddenapi/Android.bp
new file mode 100644
index 0000000..a669cad
--- /dev/null
+++ b/scripts/hiddenapi/Android.bp
@@ -0,0 +1,45 @@
+/*
+ * 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.
+ */
+
+python_binary_host {
+ name: "merge_csv",
+ main: "merge_csv.py",
+ srcs: ["merge_csv.py"],
+ version: {
+ py2: {
+ enabled: false,
+ },
+ py3: {
+ enabled: true,
+ embedded_launcher: true,
+ },
+ },
+}
+
+python_binary_host {
+ name: "generate_hiddenapi_lists",
+ main: "generate_hiddenapi_lists.py",
+ srcs: ["generate_hiddenapi_lists.py"],
+ version: {
+ py2: {
+ enabled: false,
+ },
+ py3: {
+ enabled: true,
+ embedded_launcher: true,
+ },
+ },
+}
diff --git a/scripts/hiddenapi/generate_hiddenapi_lists.py b/scripts/hiddenapi/generate_hiddenapi_lists.py
new file mode 100755
index 0000000..6816475
--- /dev/null
+++ b/scripts/hiddenapi/generate_hiddenapi_lists.py
@@ -0,0 +1,383 @@
+#!/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.
+"""Generate API lists for non-SDK API enforcement."""
+import argparse
+from collections import defaultdict, namedtuple
+import functools
+import os
+import re
+import sys
+
+# Names of flags recognized by the `hiddenapi` tool.
+FLAG_SDK = 'sdk'
+FLAG_UNSUPPORTED = 'unsupported'
+FLAG_BLOCKED = 'blocked'
+FLAG_MAX_TARGET_O = 'max-target-o'
+FLAG_MAX_TARGET_P = 'max-target-p'
+FLAG_MAX_TARGET_Q = 'max-target-q'
+FLAG_MAX_TARGET_R = 'max-target-r'
+FLAG_CORE_PLATFORM_API = 'core-platform-api'
+FLAG_PUBLIC_API = 'public-api'
+FLAG_SYSTEM_API = 'system-api'
+FLAG_TEST_API = 'test-api'
+
+# List of all known flags.
+FLAGS_API_LIST = [
+ FLAG_SDK,
+ FLAG_UNSUPPORTED,
+ FLAG_BLOCKED,
+ FLAG_MAX_TARGET_O,
+ FLAG_MAX_TARGET_P,
+ FLAG_MAX_TARGET_Q,
+ FLAG_MAX_TARGET_R,
+]
+ALL_FLAGS = FLAGS_API_LIST + [
+ FLAG_CORE_PLATFORM_API,
+ FLAG_PUBLIC_API,
+ FLAG_SYSTEM_API,
+ FLAG_TEST_API,
+]
+
+FLAGS_API_LIST_SET = set(FLAGS_API_LIST)
+ALL_FLAGS_SET = set(ALL_FLAGS)
+
+# Option specified after one of FLAGS_API_LIST to indicate that
+# only known and otherwise unassigned entries should be assign the
+# given flag.
+# For example, the max-target-P list is checked in as it was in P,
+# but signatures have changes since then. The flag instructs this
+# script to skip any entries which do not exist any more.
+FLAG_IGNORE_CONFLICTS = "ignore-conflicts"
+
+# Option specified after one of FLAGS_API_LIST to express that all
+# apis within a given set of packages should be assign the given flag.
+FLAG_PACKAGES = "packages"
+
+# Option specified after one of FLAGS_API_LIST to indicate an extra
+# tag that should be added to the matching APIs.
+FLAG_TAG = "tag"
+
+# Regex patterns of fields/methods used in serialization. These are
+# considered public API despite being hidden.
+SERIALIZATION_PATTERNS = [
+ r'readObject\(Ljava/io/ObjectInputStream;\)V',
+ r'readObjectNoData\(\)V',
+ r'readResolve\(\)Ljava/lang/Object;',
+ r'serialVersionUID:J',
+ r'serialPersistentFields:\[Ljava/io/ObjectStreamField;',
+ r'writeObject\(Ljava/io/ObjectOutputStream;\)V',
+ r'writeReplace\(\)Ljava/lang/Object;',
+]
+
+# Single regex used to match serialization API. It combines all the
+# SERIALIZATION_PATTERNS into a single regular expression.
+SERIALIZATION_REGEX = re.compile(r'.*->(' + '|'.join(SERIALIZATION_PATTERNS) + r')$')
+
+# Predicates to be used with filter_apis.
+HAS_NO_API_LIST_ASSIGNED = lambda api, flags: not FLAGS_API_LIST_SET.intersection(flags)
+IS_SERIALIZATION = lambda api, flags: SERIALIZATION_REGEX.match(api)
+
+
+class StoreOrderedOptions(argparse.Action):
+ """An argparse action that stores a number of option arguments in the order that
+ they were specified.
+ """
+ def __call__(self, parser, args, values, option_string = None):
+ items = getattr(args, self.dest, None)
+ if items is None:
+ items = []
+ items.append([option_string.lstrip('-'), values])
+ setattr(args, self.dest, items)
+
+def get_args():
+ """Parses command line arguments.
+
+ Returns:
+ Namespace: dictionary of parsed arguments
+ """
+ parser = argparse.ArgumentParser()
+ parser.add_argument('--output', required=True)
+ parser.add_argument('--csv', nargs='*', default=[], metavar='CSV_FILE',
+ help='CSV files to be merged into output')
+
+ for flag in ALL_FLAGS:
+ parser.add_argument('--' + flag, dest='ordered_flags', metavar='TXT_FILE',
+ action=StoreOrderedOptions, help='lists of entries with flag "' + flag + '"')
+ parser.add_argument('--' + FLAG_IGNORE_CONFLICTS, dest='ordered_flags', nargs=0,
+ action=StoreOrderedOptions, help='Indicates that only known and otherwise unassigned '
+ 'entries should be assign the given flag. Must follow a list of entries and applies '
+ 'to the preceding such list.')
+ parser.add_argument('--' + FLAG_PACKAGES, dest='ordered_flags', nargs=0,
+ action=StoreOrderedOptions, help='Indicates that the previous list of entries '
+ 'is a list of packages. All members in those packages will be given the flag. '
+ 'Must follow a list of entries and applies to the preceding such list.')
+ parser.add_argument('--' + FLAG_TAG, dest='ordered_flags', nargs=1,
+ action=StoreOrderedOptions, help='Adds an extra tag to the previous list of entries. '
+ 'Must follow a list of entries and applies to the preceding such list.')
+
+ return parser.parse_args()
+
+
+def read_lines(filename):
+ """Reads entire file and return it as a list of lines.
+
+ Lines which begin with a hash are ignored.
+
+ Args:
+ filename (string): Path to the file to read from.
+
+ Returns:
+ Lines of the file as a list of string.
+ """
+ with open(filename, 'r') as f:
+ lines = f.readlines();
+ lines = filter(lambda line: not line.startswith('#'), lines)
+ lines = map(lambda line: line.strip(), lines)
+ return set(lines)
+
+
+def write_lines(filename, lines):
+ """Writes list of lines into a file, overwriting the file if it exists.
+
+ Args:
+ filename (string): Path to the file to be writing into.
+ lines (list): List of strings to write into the file.
+ """
+ lines = map(lambda line: line + '\n', lines)
+ with open(filename, 'w') as f:
+ f.writelines(lines)
+
+
+def extract_package(signature):
+ """Extracts the package from a signature.
+
+ Args:
+ signature (string): JNI signature of a method or field.
+
+ Returns:
+ The package name of the class containing the field/method.
+ """
+ full_class_name = signature.split(";->")[0]
+ # Example: Landroid/hardware/radio/V1_2/IRadio$Proxy
+ if (full_class_name[0] != "L"):
+ raise ValueError("Expected to start with 'L': %s" % full_class_name)
+ full_class_name = full_class_name[1:]
+ # If full_class_name doesn't contain '/', then package_name will be ''.
+ package_name = full_class_name.rpartition("/")[0]
+ return package_name.replace('/', '.')
+
+
+class FlagsDict:
+ def __init__(self):
+ self._dict_keyset = set()
+ self._dict = defaultdict(set)
+
+ def _check_entries_set(self, keys_subset, source):
+ assert isinstance(keys_subset, set)
+ assert keys_subset.issubset(self._dict_keyset), (
+ "Error: {} specifies signatures not present in code:\n"
+ "{}"
+ "Please visit go/hiddenapi for more information.").format(
+ source, "".join(map(lambda x: " " + str(x) + "\n", keys_subset - self._dict_keyset)))
+
+ def _check_flags_set(self, flags_subset, source):
+ assert isinstance(flags_subset, set)
+ assert flags_subset.issubset(ALL_FLAGS_SET), (
+ "Error processing: {}\n"
+ "The following flags were not recognized: \n"
+ "{}\n"
+ "Please visit go/hiddenapi for more information.").format(
+ source, "\n".join(flags_subset - ALL_FLAGS_SET))
+
+ def filter_apis(self, filter_fn):
+ """Returns APIs which match a given predicate.
+
+ This is a helper function which allows to filter on both signatures (keys) and
+ flags (values). The built-in filter() invokes the lambda only with dict's keys.
+
+ Args:
+ filter_fn : Function which takes two arguments (signature/flags) and returns a boolean.
+
+ Returns:
+ A set of APIs which match the predicate.
+ """
+ return set(filter(lambda x: filter_fn(x, self._dict[x]), self._dict_keyset))
+
+ def get_valid_subset_of_unassigned_apis(self, api_subset):
+ """Sanitizes a key set input to only include keys which exist in the dictionary
+ and have not been assigned any API list flags.
+
+ Args:
+ entries_subset (set/list): Key set to be sanitized.
+
+ Returns:
+ Sanitized key set.
+ """
+ assert isinstance(api_subset, set)
+ return api_subset.intersection(self.filter_apis(HAS_NO_API_LIST_ASSIGNED))
+
+ def generate_csv(self):
+ """Constructs CSV entries from a dictionary.
+
+ Old versions of flags are used to generate the file.
+
+ Returns:
+ List of lines comprising a CSV file. See "parse_and_merge_csv" for format description.
+ """
+ lines = []
+ for api in self._dict:
+ flags = sorted(self._dict[api])
+ lines.append(",".join([api] + flags))
+ return sorted(lines)
+
+ def parse_and_merge_csv(self, csv_lines, source = "<unknown>"):
+ """Parses CSV entries and merges them into a given dictionary.
+
+ The expected CSV format is:
+ <api signature>,<flag1>,<flag2>,...,<flagN>
+
+ Args:
+ csv_lines (list of strings): Lines read from a CSV file.
+ source (string): Origin of `csv_lines`. Will be printed in error messages.
+
+ Throws:
+ AssertionError if parsed flags are invalid.
+ """
+ # Split CSV lines into arrays of values.
+ csv_values = [ line.split(',') for line in csv_lines ]
+
+ # Update the full set of API signatures.
+ self._dict_keyset.update([ csv[0] for csv in csv_values ])
+
+ # Check that all flags are known.
+ csv_flags = set()
+ for csv in csv_values:
+ csv_flags.update(csv[1:])
+ self._check_flags_set(csv_flags, source)
+
+ # Iterate over all CSV lines, find entry in dict and append flags to it.
+ for csv in csv_values:
+ flags = csv[1:]
+ if (FLAG_PUBLIC_API in flags) or (FLAG_SYSTEM_API in flags):
+ flags.append(FLAG_SDK)
+ self._dict[csv[0]].update(flags)
+
+ def assign_flag(self, flag, apis, source="<unknown>", tag = None):
+ """Assigns a flag to given subset of entries.
+
+ Args:
+ flag (string): One of ALL_FLAGS.
+ apis (set): Subset of APIs to receive the flag.
+ source (string): Origin of `entries_subset`. Will be printed in error messages.
+
+ Throws:
+ AssertionError if parsed API signatures of flags are invalid.
+ """
+ # Check that all APIs exist in the dict.
+ self._check_entries_set(apis, source)
+
+ # Check that the flag is known.
+ self._check_flags_set(set([ flag ]), source)
+
+ # Iterate over the API subset, find each entry in dict and assign the flag to it.
+ for api in apis:
+ self._dict[api].add(flag)
+ if tag:
+ self._dict[api].add(tag)
+
+
+FlagFile = namedtuple('FlagFile', ('flag', 'file', 'ignore_conflicts', 'packages', 'tag'))
+
+def parse_ordered_flags(ordered_flags):
+ r = []
+ currentflag, file, ignore_conflicts, packages, tag = None, None, False, False, None
+ for flag_value in ordered_flags:
+ flag, value = flag_value[0], flag_value[1]
+ if flag in ALL_FLAGS_SET:
+ if currentflag:
+ r.append(FlagFile(currentflag, file, ignore_conflicts, packages, tag))
+ ignore_conflicts, packages, tag = False, False, None
+ currentflag = flag
+ file = value
+ else:
+ if currentflag is None:
+ raise argparse.ArgumentError('--%s is only allowed after one of %s' % (
+ flag, ' '.join(['--%s' % f for f in ALL_FLAGS_SET])))
+ if flag == FLAG_IGNORE_CONFLICTS:
+ ignore_conflicts = True
+ elif flag == FLAG_PACKAGES:
+ packages = True
+ elif flag == FLAG_TAG:
+ tag = value[0]
+
+
+ if currentflag:
+ r.append(FlagFile(currentflag, file, ignore_conflicts, packages, tag))
+ return r
+
+
+def main(argv):
+ # Parse arguments.
+ args = vars(get_args())
+ flagfiles = parse_ordered_flags(args['ordered_flags'])
+
+ # Initialize API->flags dictionary.
+ flags = FlagsDict()
+
+ # Merge input CSV files into the dictionary.
+ # Do this first because CSV files produced by parsing API stubs will
+ # contain the full set of APIs. Subsequent additions from text files
+ # will be able to detect invalid entries, and/or filter all as-yet
+ # unassigned entries.
+ for filename in args["csv"]:
+ flags.parse_and_merge_csv(read_lines(filename), filename)
+
+ # Combine inputs which do not require any particular order.
+ # (1) Assign serialization API to SDK.
+ flags.assign_flag(FLAG_SDK, flags.filter_apis(IS_SERIALIZATION))
+
+ # (2) Merge text files with a known flag into the dictionary.
+ for info in flagfiles:
+ if (not info.ignore_conflicts) and (not info.packages):
+ flags.assign_flag(info.flag, read_lines(info.file), info.file, info.tag)
+
+ # Merge text files where conflicts should be ignored.
+ # This will only assign the given flag if:
+ # (a) the entry exists, and
+ # (b) it has not been assigned any other flag.
+ # Because of (b), this must run after all strict assignments have been performed.
+ for info in flagfiles:
+ if info.ignore_conflicts:
+ valid_entries = flags.get_valid_subset_of_unassigned_apis(read_lines(info.file))
+ flags.assign_flag(info.flag, valid_entries, filename, info.tag)
+
+ # All members in the specified packages will be assigned the appropriate flag.
+ for info in flagfiles:
+ if info.packages:
+ packages_needing_list = set(read_lines(info.file))
+ should_add_signature_to_list = lambda sig,lists: extract_package(
+ sig) in packages_needing_list and not lists
+ valid_entries = flags.filter_apis(should_add_signature_to_list)
+ flags.assign_flag(info.flag, valid_entries, info.file, info.tag)
+
+ # Mark all remaining entries as blocked.
+ flags.assign_flag(FLAG_BLOCKED, flags.filter_apis(HAS_NO_API_LIST_ASSIGNED))
+
+ # Write output.
+ write_lines(args["output"], flags.generate_csv())
+
+if __name__ == "__main__":
+ main(sys.argv)
diff --git a/scripts/hiddenapi/generate_hiddenapi_lists_test.py b/scripts/hiddenapi/generate_hiddenapi_lists_test.py
new file mode 100755
index 0000000..ff3d708
--- /dev/null
+++ b/scripts/hiddenapi/generate_hiddenapi_lists_test.py
@@ -0,0 +1,104 @@
+#!/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.
+"""Unit tests for Hidden API list generation."""
+import unittest
+from generate_hiddenapi_lists import *
+
+class TestHiddenapiListGeneration(unittest.TestCase):
+
+ def test_filter_apis(self):
+ # Initialize flags so that A and B are put on the allow list and
+ # C, D, E are left unassigned. Try filtering for the unassigned ones.
+ flags = FlagsDict()
+ flags.parse_and_merge_csv(['A,' + FLAG_SDK, 'B,' + FLAG_SDK,
+ 'C', 'D', 'E'])
+ filter_set = flags.filter_apis(lambda api, flags: not flags)
+ self.assertTrue(isinstance(filter_set, set))
+ self.assertEqual(filter_set, set([ 'C', 'D', 'E' ]))
+
+ def test_get_valid_subset_of_unassigned_keys(self):
+ # Create flags where only A is unassigned.
+ flags = FlagsDict()
+ flags.parse_and_merge_csv(['A,' + FLAG_SDK, 'B', 'C'])
+ flags.assign_flag(FLAG_UNSUPPORTED, set(['C']))
+ self.assertEqual(flags.generate_csv(),
+ [ 'A,' + FLAG_SDK, 'B', 'C,' + FLAG_UNSUPPORTED ])
+
+ # Check three things:
+ # (1) B is selected as valid unassigned
+ # (2) A is not selected because it is assigned to the allow list
+ # (3) D is not selected because it is not a valid key
+ self.assertEqual(
+ flags.get_valid_subset_of_unassigned_apis(set(['A', 'B', 'D'])), set([ 'B' ]))
+
+ def test_parse_and_merge_csv(self):
+ flags = FlagsDict()
+
+ # Test empty CSV entry.
+ self.assertEqual(flags.generate_csv(), [])
+
+ # Test new additions.
+ flags.parse_and_merge_csv([
+ 'A,' + FLAG_UNSUPPORTED,
+ 'B,' + FLAG_BLOCKED + ',' + FLAG_MAX_TARGET_O,
+ 'C,' + FLAG_SDK + ',' + FLAG_SYSTEM_API,
+ 'D,' + FLAG_UNSUPPORTED + ',' + FLAG_TEST_API,
+ 'E,' + FLAG_BLOCKED + ',' + FLAG_TEST_API,
+ ])
+ self.assertEqual(flags.generate_csv(), [
+ 'A,' + FLAG_UNSUPPORTED,
+ 'B,' + FLAG_BLOCKED + "," + FLAG_MAX_TARGET_O,
+ 'C,' + FLAG_SDK + ',' + FLAG_SYSTEM_API,
+ 'D,' + FLAG_TEST_API + ',' + FLAG_UNSUPPORTED,
+ 'E,' + FLAG_BLOCKED + ',' + FLAG_TEST_API,
+ ])
+
+ # Test unknown flag.
+ with self.assertRaises(AssertionError):
+ flags.parse_and_merge_csv([ 'Z,foo' ])
+
+ def test_assign_flag(self):
+ flags = FlagsDict()
+ flags.parse_and_merge_csv(['A,' + FLAG_SDK, 'B'])
+
+ # Test new additions.
+ flags.assign_flag(FLAG_UNSUPPORTED, set([ 'A', 'B' ]))
+ self.assertEqual(flags.generate_csv(),
+ [ 'A,' + FLAG_SDK + "," + FLAG_UNSUPPORTED, 'B,' + FLAG_UNSUPPORTED ])
+
+ # Test invalid API signature.
+ with self.assertRaises(AssertionError):
+ flags.assign_flag(FLAG_SDK, set([ 'C' ]))
+
+ # Test invalid flag.
+ with self.assertRaises(AssertionError):
+ flags.assign_flag('foo', set([ 'A' ]))
+
+ def test_extract_package(self):
+ signature = 'Lcom/foo/bar/Baz;->method1()Lcom/bar/Baz;'
+ expected_package = 'com.foo.bar'
+ self.assertEqual(extract_package(signature), expected_package)
+
+ signature = 'Lcom/foo1/bar/MyClass;->method2()V'
+ expected_package = 'com.foo1.bar'
+ self.assertEqual(extract_package(signature), expected_package)
+
+ signature = 'Lcom/foo_bar/baz/MyClass;->method3()V'
+ expected_package = 'com.foo_bar.baz'
+ self.assertEqual(extract_package(signature), expected_package)
+
+if __name__ == '__main__':
+ unittest.main()
diff --git a/scripts/hiddenapi/merge_csv.py b/scripts/hiddenapi/merge_csv.py
new file mode 100755
index 0000000..6a5b0e1
--- /dev/null
+++ b/scripts/hiddenapi/merge_csv.py
@@ -0,0 +1,69 @@
+#!/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 multiple CSV files, possibly with different columns.
+"""
+
+import argparse
+import csv
+import io
+
+from zipfile import ZipFile
+
+args_parser = argparse.ArgumentParser(description='Merge given CSV files into a single one.')
+args_parser.add_argument('--header', help='Comma separated field names; '
+ 'if missing determines the header from input files.')
+args_parser.add_argument('--zip_input', help='ZIP archive with all CSV files to merge.')
+args_parser.add_argument('--output', help='Output file for merged CSV.',
+ default='-', type=argparse.FileType('w'))
+args_parser.add_argument('files', nargs=argparse.REMAINDER)
+args = args_parser.parse_args()
+
+
+def dict_reader(input):
+ return csv.DictReader(input, delimiter=',', quotechar='|')
+
+
+if args.zip_input and len(args.files) > 0:
+ raise ValueError('Expecting either a single ZIP with CSV files'
+ ' or a list of CSV files as input; not both.')
+
+csv_readers = []
+if len(args.files) > 0:
+ for file in args.files:
+ csv_readers.append(dict_reader(open(file, 'r')))
+elif args.zip_input:
+ with ZipFile(args.zip_input) as zip:
+ for entry in zip.namelist():
+ if entry.endswith('.uau'):
+ csv_readers.append(dict_reader(io.TextIOWrapper(zip.open(entry, 'r'))))
+
+headers = set()
+if args.header:
+ fieldnames = args.header.split(',')
+else:
+ # Build union of all columns from source files:
+ for reader in csv_readers:
+ headers = headers.union(reader.fieldnames)
+ fieldnames = sorted(headers)
+
+# Concatenate all files to output:
+writer = csv.DictWriter(args.output, delimiter=',', quotechar='|', quoting=csv.QUOTE_MINIMAL,
+ dialect='unix', fieldnames=fieldnames)
+writer.writeheader()
+for reader in csv_readers:
+ for row in reader:
+ writer.writerow(row)