[NaCl SDK] nacl_io: big refactor to return error value (errno).

native_client_sdk/src/libraries/nacl_io/kernel_proxy.h

 /* Copyright (c) 2012 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.
  */
 #ifndef LIBRARIES_NACL_IO_KERNEL_PROXY_H_
 #define LIBRARIES_NACL_IO_KERNEL_PROXY_H_
 
 #include <ppapi/c/pp_instance.h>
 #include <ppapi/c/ppb.h>
 #include <pthread.h>
 #include <map>
 #include <string>
 #include <vector>
 
 #include "nacl_io/kernel_object.h"
 #include "nacl_io/mount.h"
 #include "nacl_io/ostypes.h"
 #include "nacl_io/path.h"
 
 class KernelHandle;
 class Mount;
 class MountNode;
 class PepperInterface;
 
 // KernelProxy provide one-to-one mapping for libc kernel calls.  Calls to the
 // proxy will result in IO access to the provided Mount and MountNode objects.
+//
+// NOTE: The KernelProxy is the only class that should be setting errno. All
+// other classes should return Error (as defined by nacl_io/error.h).
 class KernelProxy : protected KernelObject {
  public:
-  typedef Mount* (*MountFactory_t)(int, StringMap_t&, PepperInterface*);
+  typedef Error (*MountFactory_t)(int, StringMap_t&, PepperInterface*, Mount**);
   typedef std::map<std::string, std::string> StringMap_t;
   typedef std::map<std::string, MountFactory_t> MountFactoryMap_t;
 
   KernelProxy();
   virtual ~KernelProxy();
   // Takes ownership of |ppapi|.
   // |ppapi| may be NULL. If so, no mount that uses pepper calls can be mounted.
   virtual void Init(PepperInterface* ppapi);
 
   // KernelHandle and FD allocation and manipulation functions.
@@ skipping 61 matching lines @@
   MountFactoryMap_t factories_;
   int dev_;
   PepperInterface* ppapi_;
 
   static KernelProxy *s_instance_;
 
   DISALLOW_COPY_AND_ASSIGN(KernelProxy);
 };
 
 #endif  // LIBRARIES_NACL_IO_KERNEL_PROXY_H_