TAO/tao/Storable_FlatFileStream.h

   1 // -*- C++ -*-
   2
   3 //=============================================================================
   4 /**
   5  * @file  Storable_FlatFileStream.h
   6  *
   7  * @author Marina Spivak <marina@cs.wustl.edu>
   8  * @author Byron Harris <harrisb@ociweb.com>
   9  */
  10 //=============================================================================
  11
  12 #ifndef STORABLE_FLATFILESTREAM_H
  13 #define STORABLE_FLATFILESTREAM_H
  14
  15 #include /**/ "ace/pre.h"
  16 #include "ace/config-lite.h"
  17
  18 #if !defined (ACE_LACKS_PRAGMA_ONCE)
  19 #pragma once
  20 #endif /* ACE_LACKS_PRAGMA_ONCE */
  21
  22 #include "tao/Storable_Base.h"
  23 #include "tao/Storable_Factory.h"
  24 #include "ace/OS_NS_stdio.h"
  25
  26 TAO_BEGIN_VERSIONED_NAMESPACE_DECL
  27
  28 namespace TAO
  29 {
  30   /**
  31    * @brief A Storable_Base derived class that works with a file stream.
  32    */
  33   class TAO_Export Storable_FlatFileStream : public Storable_Base
  34   {
  35   public:
  36     Storable_FlatFileStream(const ACE_CString & file, const char * mode,
  37                             bool use_backup = Storable_Base::use_backup_default,
  38                             bool retry_on_ebadf = Storable_Base::retry_on_ebadf_default);
  39
  40     virtual ~Storable_FlatFileStream();
  41
  42     /// Check if a file exists on disk (file is not open)
  43     virtual int exists ();
  44
  45     /// Open a file (the remaining methods below all require an open file)
  46     virtual int open ();
  47
  48     /// When the locked file resides on an NFS mounted volume, occasionally
  49     /// the FD of the opened file becomes stale, when that happens the handle
  50     /// needs to be refreshed and the lock verified
  51     virtual int reopen ();
  52
  53     /// Acquire a file lock
  54     virtual int close ();
  55
  56     /// Acquire a file lock
  57     virtual int flock (int whence, int start, int len);
  58
  59     /// Release a file lock
  60     virtual int funlock (int whence, int start, int len);
  61
  62     /// Returns the last time an open file was changed
  63     virtual time_t last_changed ();
  64
  65     virtual void rewind ();
  66
  67     virtual bool flush ();
  68
  69     /// Force write of storable data to storage.
  70     /// Returns 0 on success, otherwise EOF
  71     virtual int sync ();
  72
  73     virtual Storable_Base& operator << (const ACE_CString&);
  74     virtual Storable_Base& operator >> (ACE_CString&);
  75     virtual Storable_Base& operator << (ACE_UINT32 );
  76     virtual Storable_Base& operator >> (ACE_UINT32 &);
  77     virtual Storable_Base& operator << (ACE_UINT64 );
  78     virtual Storable_Base& operator >> (ACE_UINT64 &);
  79     virtual Storable_Base& operator << (ACE_INT32 );
  80     virtual Storable_Base& operator >> (ACE_INT32 &);
  81     virtual Storable_Base& operator << (ACE_INT64 );
  82     virtual Storable_Base& operator >> (ACE_INT64 &);
  83
  84     virtual Storable_Base& operator << (const TAO_OutputCDR & cdr);
  85
  86     virtual size_t write (size_t size, const char * bytes);
  87
  88     virtual size_t read (size_t size, char * bytes);
  89
  90     virtual int restore_backup ();
  91
  92   protected:
  93     virtual void do_remove ();
  94
  95     virtual void remove_backup ();
  96
  97     virtual int create_backup ();
  98
  99   private:
 100     /// Throw a Storable_Read_Exception if the state
 101     /// is not good due to a read error.
 102     void throw_on_read_error (Storable_State state);
 103
 104     /// Throw a Storable_Write_Exception if the state
 105     /// is not good due to a write error.
 106     void throw_on_write_error (Storable_State state);
 107
 108     ACE_CString backup_file_name ();
 109
 110     ACE_OS::ace_flock_t filelock_;
 111     FILE* fl_;
 112     ACE_CString file_;
 113     ACE_CString mode_;
 114   };
 115
 116   class TAO_Export Storable_FlatFileFactory : public Storable_Factory
 117   {
 118   public:
 119     /// @param directory Directory to contain file passed in
 120     /// create_stream (). The directory is assumed to already exist.
 121     Storable_FlatFileFactory(const ACE_CString & directory,
 122                              bool use_backup = Storable_Base::use_backup_default);
 123     Storable_FlatFileFactory(const ACE_CString & directory,
 124                              bool use_backup,
 125                              bool retry_on_ebadf);
 126
 127     const ACE_CString & get_directory () const;
 128
 129     ~Storable_FlatFileFactory ();
 130
 131   // Factory Methods
 132
 133     /// Create the stream that can operate on a disk file
 134     virtual Storable_Base *create_stream (const ACE_CString & file,
 135                                           const char * mode,
 136                                           bool = false);
 137   private:
 138     static bool is_nfs (const ACE_CString &dir);
 139     ACE_CString directory_;
 140     bool use_backup_;
 141     bool retry_on_ebadf_;
 142   };
 143 }
 144
 145 TAO_END_VERSIONED_NAMESPACE_DECL
 146
 147 #include /**/ "ace/post.h"
 148
 149 #endif /* STORABLE_FLATFILESTREAM_H */