AU: SplitWriter class for parsing our full update files.

src/platform/update_engine/delta_performer.cc

 // Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "update_engine/delta_performer.h"
 #include <endian.h>
 #include <errno.h>
 #include <algorithm>
 #include <cstring>
 #include <string>
@@ skipping 92 matching lines @@
     return -errno;
   fd_ = -2;  // Set so that isn't not valid AND calls to Open() will fail.
   path_ = "";
   return 0;
 }
 
 // Wrapper around write. Returns bytes written on success or
 // -errno on error.
 // This function performs as many actions as it can, given the amount of
 // data received thus far.
-int DeltaPerformer::Write(const void* bytes, size_t count) {
+ssize_t DeltaPerformer::Write(const void* bytes, size_t count) {
   const char* c_bytes = reinterpret_cast<const char*>(bytes);
   buffer_.insert(buffer_.end(), c_bytes, c_bytes + count);
 
   if (!manifest_valid_) {
     // See if we have enough bytes for the manifest yet
     if (buffer_.size() < strlen(kDeltaMagic) +
         kDeltaVersionLength + kDeltaProtobufLengthLength) {
       // Don't have enough bytes to even know the protobuf length
       return count;
     }
@@ skipping 243 matching lines @@
         utils::PWriteAll(fd_, &zeros[0], end_byte - begin_byte, begin_byte));
   }
 
   // Update buffer.
   buffer_offset_ += operation.data_length();
   RemoveBufferHeadBytes(&buffer_, operation.data_length());
   return true;
 }
 
 }  // namespace chromeos_update_engine