path: root/ace/Remote_Tokens.h

/* -*- C++ -*- */
// $Id$


// ============================================================================
//
// = LIBRARY
//    ACE
// 
// = FILENAME
//    Remote_Tokens.h
//
// = AUTHOR
//    Douglas C. Schmidt (schmidt@cs.wustl.edu) and
//    Tim Harrison (harrison@cs.wustl.edu)
// 
// ============================================================================

#if !defined (ACE_REMOTE_MUTEX_H)
#define ACE_REMOTE_MUTEX_H

#include "ace/INET_Addr.h"
#include "ace/SOCK_Connector.h"
#include "ace/SOCK_Stream.h"
#include "ace/Synch_Options.h"
#include "ace/Local_Tokens.h"
#include "ace/Token_Request_Reply.h"
#include "ace/Synch.h"

class ACE_Export ACE_Remote_Token_Proxy : public ACE_Token_Proxy
  // = TITLE
  //    Proxy for acquiring, renewing, and releasing a distributed
  //    synchronization token.
  //
  // = DESCRIPTION
  //    The Remote_Token_Proxy class implements the mechanisms for
  //    distributed token operations.  It is similar to the
  //    ACE_Token_Proxy.
  //
  // = BUGS
  //   Distributed sleep_hooks have not been implemented.  owner_id ()
  //   is not implemented.
{
public:
  ACE_Remote_Token_Proxy (void);
  // Null construction.

  virtual ~ACE_Remote_Token_Proxy (void);
  // Death.

  int open (const char *name,
	    int ignore_deadlock = 0,
	    int debug = 0);
  // Same as Token_Proxy. <name> is the string uniquely identifying
  // the token.  <ignore_deadlock> can be 1 to disable deadlock
  // notifications.  <debug> prints debug messages.


  int initiate_connection (void);
  // Open a connection with the token server.  This only need be used
  // when the user wishes to explicitly open a connection to check if
  // the server exists.  Connections are stored in the
  // ACE_Token_Connections singleton as thread-specific data.  That
  // is, every thread has only one connection that is used for all
  // remote tokens.

  virtual int acquire (int notify = 0,
		       void (*sleep_hook)(void *) = 0,
		       ACE_Synch_Options &options =
		       ACE_Synch_Options::synch);
  // Acquire the distributed token.  If notify is specified and the
  // token is already held, the owner is notified.  options contains
  // the timeout value for the acquire call.  The timer is kept at the
  // token server.  Asynchronous operations are not supported.
  // Returns 0 on success, -1 on failure with <errno> == problem.

  virtual int tryacquire (void (*sleep_hook)(void *) = 0);
  // Try to acquire the distributed token.  If the token is already
  // held, the call returns without queueing the caller as a waiter.
  // Returns 0 on success (the token was acquired), and -1 with
  // EWOULDBLOCK if the token was already held.

  virtual int renew (int requeue_position = 0,
		     ACE_Synch_Options &options =
		     ACE_Synch_Options::synch);
  // Renew the token by offering to release it if there are any other
  // waiters, otherwise get the token back immediately.  This renew
  // has the same semantics as ACE_Local_Mutex release.  It is
  // semantically equivalent to <this->release()> followed by
  // <this->acquire()>, but it is faster.  options contains the
  // timeout value used if renew blocks.  As with acquire, the timer
  // is maintained at the token server.  If there are waiters and
  // requeue_position == -1, the caller is queued at the rear of the
  // waiter list.  Otherwise, requeue_position specifies the number of
  // waiters to "let by" before reacquiring the token (effectively,
  // the position in the waiter list.)

  virtual int release (ACE_Synch_Options &options =
		       ACE_Synch_Options::synch);
  // Release the distributed token. Similar to ACE_Local_Mutex, if the
  // caller is not the owner, it is removed from the waiter list (if
  // applicable.) Returns 0 on success, -1 on failure with <errno> ==
  // problem.

  virtual int remove (ACE_Synch_Options &options =
		      ACE_Synch_Options::synch);
  // Become interface compliant for ACE_Guard<>.  This has no
  // functionality.

  virtual void token_acquired (ACE_TPQ_Entry *);
  // Override the default to do nothing.

  virtual const char* owner_id (void);
  // the client id of the current token holder

  static void set_server_address (const ACE_INET_Addr &server_address);
  // sets the server address for all instances of ACE_Remote_Token_Proxy
  // If this isn't called, the environment variable TOKEN_SERVER is
  // checked for the server address.  If that is not specified, all
  // ACE_Remote_** operations will fail.

  void dump (void) const;
  // Dump the state of the class.

protected:

  int ignore_shadow_deadlock_;
  // if shadows report deadlock, go remote anyway

  int request_reply (ACE_Token_Request &request,
		     ACE_Synch_Options &options);
  // Perform the request and wait for the reply.
};

class ACE_Export ACE_Remote_Mutex : public ACE_Remote_Token_Proxy
// = TITLE
//    Proxy for acquiring, renewing, and releasing a distributed
//    mutex.
//
// = DESCRIPTION
//    This is the remote equivalent to ACE_Local_Mutex.  The
//    Remote_Mutex class offers methods for acquiring, renewing, and
//    releasing a distributed synchronization mutex.  Similar to
//    ACE_Local_Mutex, ACE_Remote_Token_Proxy offers recursive
//    acquisition, FIFO waiter ordering, and deadlock detection.  It
//    depends on the Token Server for its distributed synchronization
//    semantics.
{
public:
  ACE_Remote_Mutex (void);
  // Null creation.  Remote_Token_Proxy::open must be called.

  ACE_Remote_Mutex (const char *token_name,
		    int ignore_deadlock = 0,
		    int debug = 0);
  // Calls Remote_Token_Proxy::open for you.

  void dump (void) const;
  // Dump the state of the class.

  virtual ACE_Token_Proxy *clone (void) const;
  // Return deep copy.

protected:
  virtual ACE_Tokens *create_token (const char *name);
  // Make the correct type of ACE_Tokens.  This is called by the Token
  // Manager.
};

class ACE_Export ACE_Remote_RLock : public ACE_Remote_Token_Proxy
// = TITLE
//   Proxy for acquiring, renewing, and releasing a distributed
//   readers lock.
//
// = DESCRIPTION
//    This is the remote equivalent to ACE_Local_RLock. Multiple
//    readers can hold the lock simultaneously when no writers have
//    the lock.  Alternatively, when a writer holds the lock, no other
//    participants (readers or writers) may hold the lock.
//    ACE_Remote_RLock depends on the ACE Token Server for its
//    distributed synchronization semantics.
{
public:
  ACE_Remote_RLock (void);

  ACE_Remote_RLock (const char *token_name,
		    int ignore_deadlock = 0,
		    int debug = 0);

  ACE_Remote_RLock (const ACE_Remote_RLock &mutex);

  void dump (void) const;
  // Dump the state of the class.

  virtual int type (void) const;
  // Returns ACE_RW_Token::RLOCK;

  virtual ACE_Token_Proxy *clone (void) const;
  // Return deep copy.

protected:
  virtual ACE_Tokens *create_token (const char *name);
  // Make the correct type of ACE_Tokens.  This is called by the Token
  // Manager.
};

class ACE_Export ACE_Remote_WLock : public ACE_Remote_Token_Proxy
  // = TITLE
  //   Proxy for acquiring, renewing, and releasing a distributed
  //   writers lock.
  //
  // = DESCRIPTION
  //   Shields applications from details of interacting with the
  //   ACE_Token_Server.  The token_name_ is just the string that the
  //   Token Server uses to identify the token.  The client_id_ (also
  //   used by the Token Server,) identifies the owner of the token and
  //   is used for deadlock detection.
{
public:
  ACE_Remote_WLock (void);

  ACE_Remote_WLock (const char *token_name,
		    int ignore_deadlock = 0,
		    int debug = 0);

  ACE_Remote_WLock (const ACE_Remote_WLock &mutex);

  void dump (void) const;
  // Dump the state of the class.

  virtual int type (void) const;
  // Returns ACE_RW_Token::WLOCK;

  virtual ACE_Token_Proxy *clone (void) const;
  // Return deep copy.

protected:
  virtual ACE_Tokens *create_token (const char *name);
  // Make the correct type of ACE_Tokens.  This is called by the Token
  // Manager.
};

class ACE_Export ACE_TSS_Connection : public ACE_TSS<ACE_SOCK_Stream>
  // = TITLE
  //    Class for providing a connection per thread.
  //
  // = DESCRIPTION
  //    ACE_TSS_Connection provides a single access point for all
  //    threads to access thread-specific connections.  This prevents
  //    resource-sharing problems such as thread serialization.
{
public:
  // Necessary to make some compilers work...
  ACE_TSS_Connection (void);
  ~ACE_TSS_Connection (void);

  ACE_SOCK_Stream *get_connection (void);
  // retrieve the thread's connection

  virtual ACE_SOCK_Stream *make_TSS_TYPE (void) const;
  // Factory Method that creates a new SOCK Stream.

  operator ACE_SOCK_Stream *(void);
  // inheritence and operator overloading don't mix.  Redefine this
  // from ACE_TSS so that we can use it.

  static void set_server_address (const ACE_INET_Addr &server_address);
  // Set the server address.

  void dump (void) const;
  // Dump the state of the class.

protected:
  static ACE_INET_Addr server_address_;
  // The address of the Token Server used by all instances of
  // Token_Proxy.
};

#if defined (__ACE_INLINE__)
#include "ace/Remote_Tokens.i"
#endif /* __ACE_INLINE__ */

#endif /* ACE_REMOTE_TOKEN_H */