AAPT2: Share split functionality between link and optimize

Generating splits should be possible to do from the optimize command.
This means that a lot of infrastructure around split APKs can be
shared by both the optimize and link phase.

Bug: 35925830
Change-Id: Ia88b9e4bff300a56353b2f7a4a2547c8eb43a299
Test: manual
diff --git a/tools/aapt2/io/Util.cpp b/tools/aapt2/io/Util.cpp
new file mode 100644
index 0000000..15114e8
--- /dev/null
+++ b/tools/aapt2/io/Util.cpp
@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2017 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.
+ */
+
+#include "io/Util.h"
+
+#include "google/protobuf/io/zero_copy_stream_impl_lite.h"
+
+namespace aapt {
+namespace io {
+
+bool CopyInputStreamToArchive(IAaptContext* context, InputStream* in, const std::string& out_path,
+                              uint32_t compression_flags, IArchiveWriter* writer) {
+  if (context->IsVerbose()) {
+    context->GetDiagnostics()->Note(DiagMessage() << "writing " << out_path << " to archive");
+  }
+
+  if (!writer->WriteFile(out_path, compression_flags, in)) {
+    context->GetDiagnostics()->Error(DiagMessage() << "failed to write " << out_path
+                                                   << " to archive: " << writer->GetError());
+    return false;
+  }
+  return true;
+}
+
+bool CopyFileToArchive(IAaptContext* context, io::IFile* file, const std::string& out_path,
+                       uint32_t compression_flags, IArchiveWriter* writer) {
+  std::unique_ptr<io::IData> data = file->OpenAsData();
+  if (!data) {
+    context->GetDiagnostics()->Error(DiagMessage(file->GetSource()) << "failed to open file");
+    return false;
+  }
+  return CopyInputStreamToArchive(context, data.get(), out_path, compression_flags, writer);
+}
+
+bool CopyProtoToArchive(IAaptContext* context, ::google::protobuf::MessageLite* proto_msg,
+                        const std::string& out_path, uint32_t compression_flags,
+                        IArchiveWriter* writer) {
+  if (context->IsVerbose()) {
+    context->GetDiagnostics()->Note(DiagMessage() << "writing " << out_path << " to archive");
+  }
+
+  if (writer->StartEntry(out_path, compression_flags)) {
+    // Make sure CopyingOutputStreamAdaptor is deleted before we call writer->FinishEntry().
+    {
+      // Wrap our IArchiveWriter with an adaptor that implements the ZeroCopyOutputStream interface.
+      ::google::protobuf::io::CopyingOutputStreamAdaptor adaptor(writer);
+      if (!proto_msg->SerializeToZeroCopyStream(&adaptor)) {
+        context->GetDiagnostics()->Error(DiagMessage() << "failed to write " << out_path
+                                                       << " to archive");
+        return false;
+      }
+    }
+
+    if (writer->FinishEntry()) {
+      return true;
+    }
+  }
+  context->GetDiagnostics()->Error(DiagMessage() << "failed to write " << out_path
+                                                 << " to archive: " << writer->GetError());
+  return false;
+}
+
+bool Copy(OutputStream* out, InputStream* in) {
+  const void* in_buffer;
+  size_t in_len;
+  while (in->Next(&in_buffer, &in_len)) {
+    void* out_buffer;
+    size_t out_len;
+    if (!out->Next(&out_buffer, &out_len)) {
+      return !out->HadError();
+    }
+
+    const size_t bytes_to_copy = in_len < out_len ? in_len : out_len;
+    memcpy(out_buffer, in_buffer, bytes_to_copy);
+    out->BackUp(out_len - bytes_to_copy);
+    in->BackUp(in_len - bytes_to_copy);
+  }
+  return !in->HadError();
+}
+
+}  // namespace io
+}  // namespace aapt