Make a NaClDesc ctor for creating descs from NaClFileInfo.

src/trusted/desc/nacl_desc_wrapper.h

 // Copyright (c) 2012 The Native Client Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NATIVE_CLIENT_SRC_TRUSTED_DESC_NACL_DESC_WRAPPER_H_
 #define NATIVE_CLIENT_SRC_TRUSTED_DESC_NACL_DESC_WRAPPER_H_
 
 #include "native_client/src/include/nacl_base.h"
+#include "native_client/src/public/nacl_file_info.h"
 #include "native_client/src/trusted/desc/nacl_desc_base.h"
 #include "native_client/src/trusted/desc/nrd_xfer.h"
 
 namespace nacl {
 // Forward declarations.
 class DescWrapper;
 class DescWrapperCommon;
 
 // We also create a utility class that allows creation of wrappers for the
 // NaClDescs.
 class DescWrapperFactory {
  public:
   DescWrapperFactory();
   ~DescWrapperFactory();
 
   // Create a bound socket, socket address pair.
   int MakeBoundSock(DescWrapper* pair[2]);
   // Create a pair of DescWrappers for a connnected (data-only) socket.
   int MakeSocketPair(DescWrapper* pair[2]);
   // Create an IMC socket object.
   DescWrapper* MakeImcSock(NaClHandle handle);
   // Create a file descriptor object.
   DescWrapper* MakeFileDesc(int host_os_desc, int mode);
+  // As with MakeFileDesc, but with NaClFileInfo metadata.
+  DescWrapper* MakeFileDescMetadata(struct NaClFileInfo file_info,

[Mark Seaborn, 2014/05/02 20:50:40]

Is it your intention to use this new method from the Chromium side?

The reason I ask is that DescWrapper is quite deprecated, so it would be
preferable to add a C constructor that returns a NaClDesc* (and if necessary add
a NaClDesc -> DescWrapper constructor).

[jvoung (off chromium), 2014/05/14 23:42:47]

Yes, this was to make the desc and token ownership transfer happen in one
function call, instead of having separate function calls:

https://codereview.chromium.org/263683002/diff/1/ppapi/native_client/src/trus...
Okay, I didn't know that DescWrapper was deprecated.  The current plugin code
still uses that, so it seemed to match better.

I've add a C constructor (well mostly just calls the nacl_desc_io one) and use
that here to make the DescWrapper.

+                                    int mode);
   // As with MakeFileDesc, but with quota management.
   DescWrapper* MakeFileDescQuota(int host_os_desc, int mode,
                                  const uint8_t* file_id);
   // Create a DescWrapper from opening a host file.
   DescWrapper* OpenHostFile(const char* fname, int flags, int mode);
   // As with OpenHostFile, but with quota management.
   DescWrapper* OpenHostFileQuota(const char* fname, int flags, int mode,
                                  const uint8_t* file_id);
   // Create a DescWrapper for a random number generator.
   DescWrapper* OpenRng();
@@ skipping 144 matching lines @@
 
   DescWrapperCommon* common_data_;
   struct NaClDesc* desc_;
 
   DISALLOW_COPY_AND_ASSIGN(DescWrapper);
 };
 
 }  // namespace nacl
 
 #endif  // NATIVE_CLIENT_SRC_TRUSTED_DESC_NACL_DESC_WRAPPER_H_