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/* -*- C++ -*- */
// $Id$
// ============================================================================
//
// = LIBRARY
// cos
//
// = FILENAME
// Persistent_Naming_Context.h
//
// = AUTHOR
// Marina Spivak <marina@cs.wustl.edu>
//
// ============================================================================
#ifndef TAO_PERSISTENT_NAMING_CONTEXT_H
#define TAO_PERSISTENT_NAMING_CONTEXT_H
#include "Hash_Naming_Context.h"
#include "Persistent_Entries.h"
class TAO_ORBSVCS_Export TAO_Persistent_Bindings_Map : public TAO_Bindings_Map
{
// = TITLE
// Provides hash-table-based persistent storage for
// name to object bindings in a Naming Context.
//
// = DESCRIPTION
// Wrapper on top of ACE_Hash_Map_With_Allocator (which is a wrapper
// around ACE_Hash_Map_Manager). Uses ACE_Allocator (allocating
// from persistent storage) to make bindings persistent and
// supports TAO_Bindings_Map interface. Used by TAO_Persistent_Naming_Context.
public:
typedef ACE_Hash_Map_With_Allocator<TAO_Persistent_ExtId, TAO_Persistent_IntId> HASH_MAP;
// Underlying data structure - typedef for ease of use.
// = Initialization and termination methods.
TAO_Persistent_Bindings_Map (CORBA::ORB_ptr orb);
// Constructor.
int open (size_t hash_map_size,
ACE_Allocator *alloc);
// Allocate hash map of size <hash_map_size> from persistent storage
// using the <alloc>.
void set (HASH_MAP *map,
ACE_Allocator *alloc);
// The hash map has already been preallocated for us. We just need
// to set our data members take ownership of it.
virtual ~TAO_Persistent_Bindings_Map (void);
// Destructor. Does not deallocate the hash map: if an instance of
// this class goes out of scope, its hash_map remains in persistent storage.
void destroy (void);
// This method removes the hash map from persistent storage/frees up
// the memory. The hash map better be empty, since we are not
// cleaning up the insides. (We could add <close> to clean entries,
// but not the data inside the entries.
// = Accessor methods.
HASH_MAP *map (void);
// Get a pointer to the underlying hash map.
size_t total_size (void);
// Return the size of the underlying hash table.
virtual size_t current_size (void);
// Return the size of the underlying hash table.
// = Name bindings manipulation methods.
virtual int bind (const char *id,
const char *kind,
CORBA::Object_ptr obj,
CosNaming::BindingType type);
// Add a binding with the specified parameters to the table.
// Return 0 on success and -1 on failure, 1 if there already is a
// binding with <id> and <kind>.
virtual int rebind (const char *id,
const char *kind,
CORBA::Object_ptr obj,
CosNaming::BindingType type);
// Overwrite a binding containing <id> and <kind> (or create a new
// one if one doesn't exist) with the specified parameters. Return
// 0 or 1 on success. Return -1 or -2 on failure. (-2 is returned
// if the new and old bindings differ in type).
virtual int unbind (const char * id,
const char * kind);
// Remove a binding containing <id> and <kind> from the table.
// Return 0 on success and -1 on failure.
virtual int find (const char * id,
const char * kind,
CORBA::Object_ptr & obj,
CosNaming::BindingType &type);
// Find the binding containing <id> and <kind> in the table, and
// pass binding's type and object back to the caller by reference.
// Return 0 on success and -1 on failure. Note: a 'duplicated' object
// reference is assigned to <obj>, so the caller is responsible for
// its deallocation.
protected:
int open_helper (size_t hash_table_size,
void *buffer);
// Helper to the <open> method. By isolating placement new into a
// separate method, we can deal with memory allocation failures more
// efficiently. If there is a problem in HASH_MAP constructor, we
// can clean up preallocated space.
int shared_bind (const char *id,
const char *kind,
CORBA::Object_ptr obj,
CosNaming::BindingType type,
int rebind);
// Helper: factors common code from <bind> and <rebind>.
ACE_Allocator *allocator_;
// Pointer to the allocator we use to make bindings persistent.
HASH_MAP *map_;
// Pointer to the underlying hash map.
CORBA::ORB_var orb_;
// Pointer to the orb. We need it to do string/object conversions.
};
class TAO_Persistent_Context_Index;
class TAO_ORBSVCS_Export TAO_Persistent_Naming_Context : public TAO_Hash_Naming_Context
{
// = TITLE
// This class plays a role of a 'ConcreteImplementor' in the
// Bridge pattern architecture of the CosNaming::NamingContext implementation.
//
// = DESCRIPTION
// This class provides a persistent implementation of the
// NamingContext functionality, i.e., the state is preserved across
// process boundaries. Derives from TAO_Hash_Naming_Context and
// uses TAO_Persistent_Bindings_Map to store name to object bindings.
//
public:
typedef TAO_Persistent_Bindings_Map::HASH_MAP HASH_MAP;
// Underlying data structure - typedef for ease of use.
// = Initialization and termination methods.
TAO_Persistent_Naming_Context (PortableServer::POA_ptr poa,
const char *poa_id,
TAO_Persistent_Context_Index *context_index);
// Constructor. MUST be followed up by <init> to allocate the
// underlying data structure from persistent storage!
int init (size_t hash_table_size = ACE_DEFAULT_MAP_SIZE);
// Allocate the underlying data structure from persistent storage.
// Returns 0 on success and -1 on failure.
TAO_Persistent_Naming_Context (PortableServer::POA_ptr poa,
const char *poa_id,
TAO_Persistent_Context_Index *context_index,
HASH_MAP * map,
ACE_UINT32 *counter);
// Constructor that takes in preallocated data structure and takes
// ownership of it. This constructor is for 'recreating' servants
// from persistent state.
virtual ~TAO_Persistent_Naming_Context (void);
// Destructor.
// = Utility methods.
static CosNaming::NamingContext_ptr make_new_context (PortableServer::POA_ptr poa,
const char *poa_id,
size_t context_size,
TAO_Persistent_Context_Index *ind,
CORBA::Environment &ACE_TRY_ENV);
// This utility method factors out the code needed to create a new
// Persistent Naming Context servant and activate it under the
// specified POA with the specified id. This function is static so
// that the code can be used, both from inside the class (e.g., <new_context>),
// and from outside (e.g., Naming_Utils.cpp).
// = Methods not implemented in TAO_Hash_Naming_Context.
virtual CosNaming::NamingContext_ptr new_context (CORBA::Environment &ACE_TRY_ENV);
// This operation returns a new naming context implemented by the
// same naming server in which the operation was invoked. The
// context is not bound.
virtual void list (CORBA::ULong how_many,
CosNaming::BindingList_out &bl,
CosNaming::BindingIterator_out &bi,
CORBA::Environment &ACE_TRY_ENV);
// Returns at most the requested number of bindings <how_many> in
// <bl>. If the naming context contains additional bindings, they
// are returned with a BindingIterator. In the naming context does
// not contain any additional bindings <bi> returned as null.
protected:
void set_cleanup_level (int level);
// Set <destroyed_> flag (inherited from TAO_Hash_Naming_Context) to
// <level>. Legal values for <destroyed_> are 0, 1, and 2. The
// values specify the extent of cleanup that should take place in the
// context's destructor:
// '0' - no cleanup (e.g., if the context goes out of scope, but
// it's state is to remain in persistent storage);
// '1' - free up the underlying data structure in persistent storage
// (e.g., if the initialization of this context was only partially completed
// due to some failures, and we need to roll back);
// '2' - free up the underlying data structure, and deregister this
// naming context from its <index_> (e.g., if the context had
// <destroy> method invoked and needs to be completely removed from existence).
ACE_UINT32 *counter_;
// Counter used for generation of POA ids for children Naming
// Contexts.
TAO_Persistent_Bindings_Map *persistent_context_;
// A pointer to the underlying data structure used to store name
// bindings. While our superclass (TAO_Hash_Naming_Context) also
// maintains a pointer to the data structure, keeping this pointer
// around saves us from the need to downcast when invoking
// non-virtual methods.
TAO_Persistent_Context_Index *index_;
// A pointer to the index object of this naming service: it keeps
// track of all the naming contexts created. Every time we make a
// new context or destroy one, we need to make an entry there.
// Also, we get the allocator needed to initialize us from this guy.
};
#endif /* TAO_PERSISTENT_NAMING_CONTEXT_H */
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