AU: SplitWriter class for parsing our full update files.

src/platform/update_engine/decompressing_file_writer.cc

 // Copyright (c) 2009 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/decompressing_file_writer.h"
 
 namespace chromeos_update_engine {
 
 //  typedef struct z_stream_s {
 //      Bytef    *next_in;  /* next input byte */
 //      uInt     avail_in;  /* number of bytes available at next_in */
 //      uLong    total_in;  /* total nb of input bytes read so far */
 //
 //      Bytef    *next_out; /* next output byte should be put there */
 //      uInt     avail_out; /* remaining free space at next_out */
 //      uLong    total_out; /* total nb of bytes output so far */
 //
 //      char     *msg;      /* last error message, NULL if no error */
 //      struct internal_state FAR *state; /* not visible by applications */
 //
 //      alloc_func zalloc;  /* used to allocate the internal state */
 //      free_func  zfree;   /* used to free the internal state */
 //      voidpf     opaque;  /* private data object passed to zalloc and zfree */
 //
 //      int     data_type;  /* best guess about the data type: binary or text */
 //      uLong   adler;      /* adler32 value of the uncompressed data */
 //      uLong   reserved;   /* reserved for future use */
 //  } z_stream;
 
-int GzipDecompressingFileWriter::Write(const void* bytes, size_t count) {
+ssize_t GzipDecompressingFileWriter::Write(const void* bytes, size_t count) {
   // Steps:
   // put the data on next_in
   // call inflate until it returns nothing, each time writing what we get
   // check that next_in has no data left.
 
   // It seems that zlib can keep internal buffers in the stream object,
   // so not all data we get fed to us this time will necessarily
   // be written out this time (in decompressed form).
 
   if (stream_.avail_in) {
@@ skipping 30 matching lines @@
       // Inflate returned no data; we're done for now. Make sure no
       // input data remain.
       CHECK_EQ(0, stream_.avail_in);
       break;
     }
   }
   return count;
 }
 
 }  // namespace chromeos_update_engine