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/* -*- C++ -*- */
// $Id$
// ============================================================================
//
// = LIBRARY
// cos
//
// = FILENAME
// Persistent_Context_Index.h
//
// = AUTHOR
// Marina Spivak <marina@cs.wustl.edu>
//
// ============================================================================
#ifndef TAO_PERSISTENT_CONTEXT_INDEX_H
#define TAO_PERSISTENT_CONTEXT_INDEX_H
#include "Persistent_Entries.h"
class TAO_ORBSVCS_Export TAO_Persistent_Context_Index
{
// = TITLE
// This class facilitates implementation of Persistent
// Naming Service. It keeps track, centrally, of several pieces of
// info for each Persistent Naming Context, allowing to perform the
// initialization necessary for each Naming Context to
// restore the state of the Naming Service from persistent storage
// on server start-up.
//
// = DESCRIPTION
// This class creates a memory-mapped file, allocates a hash
// table from that file, and uses the hash table to store POA id,
// and table and counter pointers for each Persistent Naming
// Context. There are methods for adding and deleting entries
// from this hash table as new Persistent Naming Contexts are
// created and old ones are destroyed. This hash table
// facilitates Persistent Naming Context servant initialization
// upon Naming Server start-up.
public:
// = Some typedefs for convenience.
typedef ACE_Hash_Map_With_Allocator<TAO_Persistent_Index_ExtId,
TAO_Persistent_Index_IntId> CONTEXT_INDEX;
// Hash map in which we will store info about each Persistent Naming Context.
typedef ACE_Hash_Map_With_Allocator<TAO_Persistent_ExtId,
TAO_Persistent_IntId> CONTEXT;
// Hash map used by Persistent Naming Context to keep its state.
typedef ACE_Allocator_Adapter <ACE_Malloc <ACE_MMAP_MEMORY_POOL, ACE_SYNCH_MUTEX>
> ALLOCATOR;
// Allocator we will be using to make the Naming Service persistent.
// = Initialization and termination methods.
TAO_Persistent_Context_Index (CORBA::ORB_ptr orb,
PortableServer::POA_ptr poa);
// Constructor.
int open (LPCTSTR file_name,
void * base_address = ACE_DEFAULT_BASE_ADDR);
// Create ACE_Allocator, open/create memory-mapped file with the
// specified file name/base address. Find or allocate <index_>.
// Return 0 on success or -1 on failure.
int init (size_t context_size);
// If <index_> contains no entries (i.e., was just created), create
// a root Persistent Naming Context servant with table of size
// <context_size>, and make an entry for it
// in the <index_>. If <index_> contains entries, create a
// Persistent Naming Context servant for each entry. Return 0 on
// success and -1 on failure.
~TAO_Persistent_Context_Index (void);
// Destructor. The memory mapped file that was opened/created is
// not deleted, since we want it to keep the state of the Naming
// Service until the next run.
// = Methods for adding/removing entries.
int bind (const char *poa_id,
ACE_UINT32 *&counter,
CONTEXT *hash_map);
// Create an entry for a Persistent Naming Context in <index_>,
// i.e., a context with <poa_id>, <counter> and <hash_map> has just
// been created, and is registering with us.
int unbind (const char *poa_id);
// Remove an entry for the Persistent Naming Context with <poa_id>
// from <index_> (i.e., this context has just been destroyed).
// = Accessors.
ACE_Allocator *allocator (void);
// Return allocator.
CORBA::ORB_ptr orb (void);
// Return orb pointer.
char *root_ior (void);
// Return ior of the root Naming Context (returns a copy - must be
// deallocated by the user).
private:
int recreate_all (void);
// Helper for the <init> method. Iterates over <index_>, and
// creates a servant for each entry.
int create_index (void);
// Helper for the <open> method.
int create_index_helper (void *buffer);
// Helper for <create_index> method: places hash table into an
// allocated space.
ACE_SYNCH_MUTEX lock_;
// Lock to prevent multiple threads from modifying entries in the
// <index_> simultanneously.
ALLOCATOR *allocator_;
// Allocator that deals out memory from a memory-mapped file. We
// use it here, and in TAO_Persistent_Naming_Context, whenever we
// deal with data that should be kept in persistent store.
CONTEXT_INDEX *index_;
// Hash map where we keep entries for all Persistent Naming
// Contexts.
LPCTSTR index_file_;
// Name of the memory-mapped file used by <allocator_>.
void *base_address_;
// Base address for the memory-mapped file.
CORBA::ORB_var orb_;
// ORB. We use it for several object_to_string conversions, and
// keep it around for Persistent Naming Contexts' use.
PortableServer::POA_var poa_;
// POA under which to register Persistent Naming Context servants
// during start-up.
CORBA::String_var root_ior_;
// The ior of the root Naming Context.
};
#endif /* TAO_PERSISTENT_CONTEXT_INDEX_H */
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