Revert "Buck: Wipe out the machinery for merging JARs"

We need it again after the upgrade to Lucene 5.4.1.

This reverts commit 08cc835f99.

Change-Id: I1798907e5e792005e6b78fcf9bbaaf36535d711b

lib/maven.defs

@@ -147,3 +147,31 @@ def maven_jar(
       source_jar = ':%s__download_src' % name if srcjar else None,
       visibility = visibility,
     )
+
+
+def merge_maven_jars(
+    name,
+    srcs,
+    visibility = []):
+
+  def cmd(jars):
+    return ('$(location //tools:merge_jars) $OUT '
+            + ' '.join(['$(location %s)' % j for j in jars]))
+
+  genrule(
+    name = '%s__merged_bin' % name,
+    cmd = cmd(['%s__download_bin' % s for s in srcs]),
+    out = '%s__merged.jar' % name,
+  )
+  genrule(
+    name = '%s__merged_src' % name,
+    cmd = cmd(['%s__download_src' % s for s in srcs]),
+    # tools/eclipse/project.py requires -src.jar suffix.
+    out = '%s__merged-src.jar' % name,
+  )
+  prebuilt_jar(
+    name = name,
+    binary_jar = ':%s__merged_bin' % name,
+    source_jar = ':%s__merged_src' % name,
+    visibility = visibility,
+  )

tools/BUCK

@@ -5,6 +5,12 @@ python_binary(
   visibility = ['PUBLIC'],
 )
 
+python_binary(
+  name = 'merge_jars',
+  main = 'merge_jars.py',
+  visibility = ['PUBLIC'],
+)
+
 python_binary(
   name = 'pack_war',
   main = 'pack_war.py',

tools/merge_jars.py

@@ -0,0 +1,50 @@
+#!/usr/bin/env python
+# Copyright (C) 2015 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.
+
+from __future__ import print_function
+import collections
+import sys
+import zipfile
+
+
+if len(sys.argv) < 3:
+  print('usage: %s <out.zip> <in.zip>...' % sys.argv[0], file=sys.stderr)
+  exit(1)
+
+outfile = sys.argv[1]
+infiles = sys.argv[2:]
+seen = set()
+SERVICES = 'META-INF/services/'
+
+try:
+  with zipfile.ZipFile(outfile, 'w') as outzip:
+    services = collections.defaultdict(lambda: '')
+    for infile in infiles:
+      with zipfile.ZipFile(infile) as inzip:
+        for info in inzip.infolist():
+          n = info.filename
+          if n in seen:
+            continue
+          elif n.startswith(SERVICES):
+            # Concatenate all provider configuration files.
+            services[n] += inzip.read(n)
+            continue
+          outzip.writestr(info, inzip.read(n))
+          seen.add(n)
+
+    for n, v in services.iteritems():
+      outzip.writestr(n, v)
+except Exception as err:
+  exit('Failed to merge jars: %s' % err)