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

native_client_sdk/src/libraries/nacl_io/mount_node_dir.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_MOUNT_NODE_DIR_H_
 #define LIBRARIES_NACL_IO_MOUNT_NODE_DIR_H_
 
 #include <map>
 #include <string>
 
 #include "nacl_io/mount_node.h"
 
 struct dirent;
 
 class MountDev;
 class MountHtml5Fs;
 class MountHttp;
 class MountMem;
 
 class MountNodeDir : public MountNode {
  protected:
   explicit MountNodeDir(Mount* mnt);
   virtual ~MountNodeDir();
 
  public:
   typedef std::map<std::string, MountNode*> MountNodeMap_t;
 
-  virtual int FTruncate(off_t size);
-  virtual int GetDents(size_t offs, struct dirent* pdir, size_t count);
-  virtual int Read(size_t offs, void *buf, size_t count);
-  virtual int Write(size_t offs, void *buf, size_t count);
+  virtual Error FTruncate(off_t size);
+  virtual Error GetDents(size_t offs,
+                         struct dirent* pdir,
+                         size_t count,
+                         int* out_bytes);
+  virtual Error Read(size_t offs, void *buf, size_t count, int* out_bytes);
+  virtual Error Write(size_t offs, void *buf, size_t count, int* out_bytes);
 
   // Adds a finds or adds a directory entry as an INO, updating the refcount
-  virtual int AddChild(const std::string& name, MountNode *node);
-  virtual int RemoveChild(const std::string& name);
-  virtual MountNode* FindChild(const std::string& name);
+  virtual Error AddChild(const std::string& name, MountNode *node);
+  virtual Error RemoveChild(const std::string& name);
+  virtual Error FindChild(const std::string& name, MountNode** out_node);
   virtual int ChildCount();
 
 
 protected:
    void ClearCache();
    void BuildCache();
 
 private:
   struct dirent* cache_;
   MountNodeMap_t map_;
 
   friend class MountDev;
   friend class MountMem;
   friend class MountHttp;
   friend class MountHtml5Fs;
 };
 
 #endif  // LIBRARIES_NACL_IO_MOUNT_NODE_DIR_H_