Handles missing classes.jar in aar_import gracefully, by creating an empty jar file instead of crashing Bazel.

--
MOS_MIGRATED_REVID=135405636

4 files changed, 121 insertions, 0 deletions

diff --git a/tools/zip/BUILD b/tools/zip/BUILD
index cfb986b993..4ccf9f7273 100644
--- a/tools/zip/BUILD
+++ b/tools/zip/BUILD
@@ -17,3 +17,15 @@ sh_test(
     srcs = ["zip_manifest_creator_test.sh"],
     data = [":zip_manifest_creator"],
 )
+
+py_binary(
+    name = "embedded_jar_extractor",
+    srcs = ["embedded_jar_extractor.py"],
+    deps = ["//third_party/py/gflags"],
+)
+
+py_test(
+    name = "embedded_jar_extractor_test",
+    srcs = ["embedded_jar_extractor_test.py"],
+    deps = [":embedded_jar_extractor"],
+)
diff --git a/tools/zip/BUILD.tools b/tools/zip/BUILD.tools
index 58f9267f2f..542ddce946 100644
--- a/tools/zip/BUILD.tools
+++ b/tools/zip/BUILD.tools
@@ -10,3 +10,9 @@ sh_binary(
     srcs = ["zip_manifest_creator.sh"],
     data = [":zipper"],
 )
+
+py_binary(
+    name = "embedded_jar_extractor",
+    srcs = ["embedded_jar_extractor.py"],
+    deps = ["//third_party/py/gflags"],
+)
diff --git a/tools/zip/embedded_jar_extractor.py b/tools/zip/embedded_jar_extractor.py
new file mode 100644
index 0000000000..1111b2993e
--- /dev/null
+++ b/tools/zip/embedded_jar_extractor.py
@@ -0,0 +1,53 @@
+# Copyright 2016 The Bazel Authors. All rights reserved.
+#
+# 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.
+
+"""A tool for extracting a jar file from an archive and failing gracefully.
+
+If the jar file is present within the archive, it is extracted into the output
+directory. If not, an empty jar is created in the output directory.
+"""
+
+import os
+import sys
+import zipfile
+
+from third_party.py import gflags
+
+FLAGS = gflags.FLAGS
+
+gflags.DEFINE_string("input_archive", None, "Input archive")
+gflags.MarkFlagAsRequired("input_archive")
+gflags.DEFINE_string("filename", None, "Filename of JAR to extract")
+gflags.MarkFlagAsRequired("filename")
+gflags.DEFINE_string("output_dir", None, "Output directory")
+gflags.MarkFlagAsRequired("output_dir")
+
+
+def ExtractEmbeddedJar(input_archive, filename, output_dir):
+  with zipfile.ZipFile(input_archive, "r") as archive:
+    if filename in archive.namelist():
+      archive.extract(filename, output_dir)
+    else:
+      with zipfile.ZipFile(os.path.join(output_dir, filename), "w") as jar:
+        # All jar files must contain META-INF/MANIFEST.MF.
+        jar.writestr("META-INF/MANIFEST.MF", ("Manifest-Version: 1.0\n"
+                                              "Created-By: Bazel\n"))
+
+
+def main():
+  ExtractEmbeddedJar(FLAGS.input_archive, FLAGS.filename, FLAGS.output_dir)
+
+if __name__ == "__main__":
+  FLAGS(sys.argv)
+  main()
diff --git a/tools/zip/embedded_jar_extractor_test.py b/tools/zip/embedded_jar_extractor_test.py
new file mode 100644
index 0000000000..568e0b3366
--- /dev/null
+++ b/tools/zip/embedded_jar_extractor_test.py
@@ -0,0 +1,50 @@
+# Copyright 2016 The Bazel Authors. All rights reserved.
+#
+# 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.
+
+"""Tests for embedded_jar_extractor."""
+
+import filecmp
+import os
+import unittest
+import zipfile
+
+from tools.zip import embedded_jar_extractor
+
+
+class EmbeddedJarExtractorTest(unittest.TestCase):
+  """Unit tests for embedded_jar_extractor.py."""
+
+  def testPassingJarFile(self):
+    bjar = zipfile.ZipFile("b.jar", "w")
+    bjar.close()
+    azip = zipfile.ZipFile("a.zip", "w")
+    azip.write("b.jar")
+    azip.close()
+    if not os.path.exists("output"):
+      os.mkdir("output")
+    embedded_jar_extractor.ExtractEmbeddedJar("a.zip", "b.jar", "output")
+    self.assertTrue(filecmp.cmp("b.jar", "output/b.jar"))
+
+  def testMissingJarFile(self):
+    azip = zipfile.ZipFile("a.zip", "w")
+    azip.close()
+    if not os.path.exists("output"):
+      os.mkdir("output")
+    embedded_jar_extractor.ExtractEmbeddedJar("a.zip", "b.jar", "output")
+    bjar = zipfile.ZipFile("output/b.jar", "r")
+    self.assertEqual(["META-INF/MANIFEST.MF"], bjar.namelist())
+
+
+if __name__ == "__main__":
+  unittest.main()