[WIP] Provided file system from NACL.

ppapi/examples/filesystem_provider/memfilesystem.h

+// Copyright 2015 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 MEMFILESYSTEM_H_
+#define MEMFILESYSTEM_H_
+
+#include "inode.h"
+
+namespace filesystem{
+
+// The filesystem Inode reference counter
+class BookKeeper{
+public:
+  virtual void AddLink(unsigned long long)=0;
+  virtual void RemoveLink(unsigned long long)=0;
+};
+
+
+class Filesystem : public BookKeeper{
+ public:
+  Filesystem();
+  virtual ~Filesystem();
+
+  typedef enum{
+       File_System_Error_NONE,
+       File_System_Error_NOT_FOUND,
+       File_System_Error_EXISTS,
+       File_System_Error_FAILED,
+       File_System_Error_UNKNOWN
+  }File_System_Errors;
+  typedef std::pair< std::string, Inode* > NameInodePair;
+  // The meta param contains a pointer to an Inode which is
+  // not owned
+  int GetMetadata(const std::string& path, NameInodePair& meta);
+  int CreateDirectory(const std::string& path, bool recursive);
+  // The same Inode is used, references are modified
+  int MoveEntry(const std::string& source_path, const std::string& target_path);
+  // Copies an entry to another location by adding references to
+  // the underlying Inodes
+  int CopyEntry(const std::string& source_path,const std::string& target_path);
+  // Deletes entries and decrements references
+  int DeleteEntry(const std::string& path, bool recursive);
+  // The vector of metas contains an array of NameInodePair encapsulating
+  // not owned pointers
+  int ReadDirectory(const std::string& path, std::vector<NameInodePair>& metas);
+  // File operations that are delegated to a specific
+  // InodeFile based on path
+  int CreateFile(const std::string& file_path);
+  int Truncate(const std::string& file_path, size_t length);
+  int WriteToFile(
+    const std::string& file_path,
+    size_t offset,
+    size_t data_size,
+    const char* data );
+  int ReadFromFile(
+    const std::string &file_path,
+    size_t offset,
+    size_t* int_out_length,
+    const char** out_data);
+  // Inode management
+  virtual void AddLink(unsigned long long);
+  virtual void RemoveLink(unsigned long long);
+ protected:
+  // Internal function for Inode management
+  Inode* GetInode(unsigned long long);
+  void PutInode(unsigned long long inode_number, Inode*);
+  void RemoveInode(unsigned long long);
+  unsigned long long GetInodeFromPath(const std::string& path);
+
+  unsigned long long GetNextInodeNumber();
+  // Inode index
+  unsigned long long currentInode_;
+  // "Must have" entry of the filesystem
+  const std::string  root_path;
+  unsigned long long root_inode;
+
+  // A pair composed of a ref counter and an owned pointer
+  typedef std::pair< int, Inode*>  InodePair;
+  typedef std::map<unsigned long long, InodePair> ListOfInodes;
+  typedef ListOfInodes::iterator ListOfInodesIterator;
+  ListOfInodes inodesList_;
+};
+
+}// namespace filesystem
+
+#endif // MEMFILESYSTEM_H_