Add an API to unpack Zip files directly from and to file descriptors.

chrome/common/zip_internal.cc

 // Copyright (c) 2011 The Chromium 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 "chrome/common/zip.h"
 
 #include "base/utf_string_conversions.h"
 #include "third_party/zlib/contrib/minizip/unzip.h"
 #include "third_party/zlib/contrib/minizip/zip.h"
 #if defined(OS_WIN)
@@ skipping 63 matching lines @@
   zlib_filefunc_def* zip_func_ptrs = NULL;
 #if defined(OS_WIN)
   zlib_filefunc_def zip_funcs;
   fill_win32_filefunc(&zip_funcs);
   zip_funcs.zopen_file = ZipOpenFunc;
   zip_func_ptrs = &zip_funcs;
 #endif
   return unzOpen2(file_name_utf8.c_str(), zip_func_ptrs);
 }
 
+#if defined(OS_POSIX)
+unzFile OpenFdForUnzipping(int zip_fd) {
+  zlib_filefunc_def zip_funcs;
+  fill_fdopen_filefunc(&zip_funcs, zip_fd);
+  // Passing dummy "fd" filename to zlib.
+  return unzOpen2("fd", &zip_funcs);
+}
+#endif
+
 zipFile OpenForZipping(const std::string& file_name_utf8, int append_flag) {
   zlib_filefunc_def* zip_func_ptrs = NULL;
 #if defined(OS_WIN)
   zlib_filefunc_def zip_funcs;
   fill_win32_filefunc(&zip_funcs);
   zip_funcs.zopen_file = ZipOpenFunc;
   zip_func_ptrs = &zip_funcs;
 #endif
   return zipOpen2(file_name_utf8.c_str(),
                   append_flag,
                   NULL,  // global comment
                   zip_func_ptrs);
 }
 
 }  // namespace internal
 }  // namespace zip