mirror of https://github.com/tongzx/nt5src
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
529 lines
15 KiB
529 lines
15 KiB
/*
|
|
* channel.h
|
|
*
|
|
* Copyright (c) 1993 - 1995 by DataBeam Corporation, Lexington, KY
|
|
*
|
|
* Abstract:
|
|
* This is the interface file for the Channel class. This class represents
|
|
* both static and assigned channels within an MCS domain. This class is
|
|
* also the base class for all other types of channels in MCS. It defines
|
|
* the default behavior that can be inherited by these other classes.
|
|
*
|
|
* Instances of the Channel class have three primary responsibilities:
|
|
* managing the join/leave process; sending data; and issuing merge
|
|
* requests during a domain merger.
|
|
*
|
|
* When a user tries to join a channel, the request is sent to the Channel
|
|
* object that represents the channel. The Channel object can then decide
|
|
* whether or not to allow the join. By overriding the appropriate
|
|
* member functions, derived classes can change the criteria by which
|
|
* this decision is made.
|
|
*
|
|
* All Channel objects maintain an internal list of which attachments are
|
|
* joined to the channel they represent. When data is sent on the channel,
|
|
* the request is sent to the Channel object, who then knows how to route
|
|
* the data. The data is sent to all the appropriate attachments.
|
|
*
|
|
* During a domain information base merger, all Channel objects will be
|
|
* asked to issue a merge request upward toward the new top provider. The
|
|
* merge request will be built using information contained in the Channel
|
|
* object.
|
|
*
|
|
* All public member functions of this class are declared as virtual, so
|
|
* that they can be overridden in case a derived class has to modify the
|
|
* behavior.
|
|
*
|
|
* Caveats:
|
|
* None.
|
|
*
|
|
* Author:
|
|
* James P. Galvin, Jr.
|
|
*/
|
|
#ifndef _CHANNEL_
|
|
#define _CHANNEL_
|
|
|
|
|
|
/*
|
|
* This is a dictionary of channels that exist within the current domain.
|
|
* The key to the dictionary is the channel ID, by which channels are
|
|
* identified. The value is a pointer to an object of class Channel. By
|
|
* definition, if a channel is in the list, then it exists and knows how
|
|
* to respond to channel related activity. If a channel is not in the
|
|
* list, then it does not exist (from the point-of-view of this MCS
|
|
* provider).
|
|
*/
|
|
|
|
/*
|
|
* This is the class definition for class Channel.
|
|
*/
|
|
class Channel
|
|
{
|
|
public:
|
|
|
|
Channel (
|
|
ChannelID channel_id,
|
|
PDomain local_provider,
|
|
PConnection top_provider,
|
|
CChannelList2 *channel_list,
|
|
CAttachmentList *attachment_list);
|
|
Channel (
|
|
ChannelID channel_id,
|
|
PDomain local_provider,
|
|
PConnection top_provider,
|
|
CChannelList2 *channel_list,
|
|
CAttachmentList *attachment_list,
|
|
PConnection pConn);
|
|
virtual ~Channel ();
|
|
|
|
void SetTopProvider(PConnection top_provider) { m_pConnToTopProvider = top_provider; }
|
|
BOOL IsTopProvider(void) { return (NULL == m_pConnToTopProvider); }
|
|
|
|
virtual Channel_Type GetChannelType ();
|
|
virtual BOOL IsValid ();
|
|
virtual CAttachment *GetAttachment(void) { return NULL; }
|
|
virtual Void IssueMergeRequest ();
|
|
virtual Void ChannelJoinRequest (
|
|
CAttachment *originator,
|
|
UserID uidInitiator,
|
|
ChannelID channel_id);
|
|
Void ChannelJoinConfirm (
|
|
CAttachment *originator,
|
|
Result result,
|
|
UserID uidInitiator,
|
|
ChannelID requested_id,
|
|
ChannelID channel_id);
|
|
Void ChannelLeaveRequest (
|
|
CAttachment *originator,
|
|
CChannelIDList *channel_id_list);
|
|
virtual Void SendDataRequest (
|
|
CAttachment *originator,
|
|
UINT type,
|
|
PDataPacket data_packet);
|
|
Void SendDataIndication (
|
|
PConnection originator,
|
|
UINT type,
|
|
PDataPacket data_packet);
|
|
|
|
protected:
|
|
ChannelID Channel_ID;
|
|
PDomain m_pDomain;
|
|
PConnection m_pConnToTopProvider;
|
|
CChannelList2 *m_pChannelList2;
|
|
CAttachmentList *m_pAttachmentList;
|
|
CAttachmentList m_JoinedAttachmentList;
|
|
};
|
|
|
|
/*
|
|
* Channel (
|
|
* ChannelID channel_id,
|
|
* PDomain local_provider,
|
|
* PConnection top_provider,
|
|
* PChannelList channel_list,
|
|
* PAttachmentList attachment_list)
|
|
*
|
|
* Functional Description:
|
|
* This is the normal constructor for the Channel class. It simply
|
|
* initializes the instance variables that identify the channel, the local
|
|
* provider, and the top provider. The attachment list is empty by
|
|
* default.
|
|
*
|
|
* Formal Parameters:
|
|
* channel_id (i)
|
|
* This is the ID of the channel object. By keeping track of this
|
|
* internally, it doesn't have to be passed in for every operation.
|
|
* local_provider (i)
|
|
* This is the identity of the local provider. A Channel object
|
|
* needs this since it issues MCS commands on behalf of the local
|
|
* provider.
|
|
* top_provider (i)
|
|
* This is a pointer to the top provider. This is used by the
|
|
* Channel object when it needs to issue a request to the Top
|
|
* Provider. If NULL, then this is the top provider.
|
|
* channel_list (i)
|
|
* This is a pointer to the domain's channel list, which identifies
|
|
* all valid channels in the domain. This is used by channel objects
|
|
* to validate user IDs.
|
|
* attachment_list (i)
|
|
* This is a pointer to the domain's attachment list, which identifies
|
|
* all valid attachments in the domain. This is used by channel
|
|
* objects to validate joined attachments.
|
|
*
|
|
* Return Value:
|
|
* None.
|
|
*
|
|
* Side Effects:
|
|
* None.
|
|
*
|
|
* Caveats:
|
|
* None.
|
|
*/
|
|
|
|
/*
|
|
* Channel (
|
|
* ChannelID channel_id,
|
|
* PDomain local_provider,
|
|
* PConnection top_provider,
|
|
* PChannelList channel_list,
|
|
* PAttachmentList attachment_list,
|
|
* PCommandTarget attachment)
|
|
*
|
|
* Functional Description:
|
|
* This is a secondary version of the constructor that is used only during
|
|
* merge operations. The only difference between this one and the one
|
|
* above is that this one allows the specification of an initial
|
|
* attachment. This allows a Channel object to be constructed with an
|
|
* existing attachment, without the transmission of a ChannelJoinConfirm.
|
|
*
|
|
* Remember that if a Channel object is constructed, and then a join
|
|
* request is used to add an attachment, a Channel object automatically
|
|
* issues a join confirm. This constructor allows that to be bypassed
|
|
* during a merger when a join confirm is inappropriate.
|
|
*
|
|
* Formal Parameters:
|
|
* channel_id (i)
|
|
* This is the ID of the channel object. By keeping track of this
|
|
* internally, it doesn't have to be passed in for every operation.
|
|
* local_provider (i)
|
|
* This is the identity of the local provider. A Channel object
|
|
* needs this since it issues MCS commands on behalf of the local
|
|
* provider.
|
|
* top_provider (i)
|
|
* This is a pointer to the top provider. This is used by the
|
|
* Channel object when it needs to issue a request to the Top
|
|
* Provider. If NULL, then this is the top provider.
|
|
* channel_list (i)
|
|
* This is a pointer to the domain's channel list, which identifies
|
|
* all valid channels in the domain. This is used by channel objects
|
|
* to validate user IDs.
|
|
* attachment_list (i)
|
|
* This is a pointer to the domain's attachment list, which identifies
|
|
* all valid attachments in the domain. This is used by channel
|
|
* objects to validate joined attachments.
|
|
* attachment (i)
|
|
* This is the initial attachment for the channel. A channel join
|
|
* confirm is NOT issued to the attachment.
|
|
*
|
|
* Return Value:
|
|
* None.
|
|
*
|
|
* Side Effects:
|
|
* None.
|
|
*
|
|
* Caveats:
|
|
* None.
|
|
*/
|
|
|
|
/*
|
|
* ~Channel ()
|
|
*
|
|
* Functional Description:
|
|
* This is the Channel class destructor. It clears the joined attachment
|
|
* list, sending channel leave indications to any user that is locally
|
|
* attached.
|
|
*
|
|
* Formal Parameters:
|
|
* None.
|
|
*
|
|
* Return Value:
|
|
* None.
|
|
*
|
|
* Side Effects:
|
|
* None.
|
|
*
|
|
* Caveats:
|
|
* None.
|
|
*/
|
|
|
|
/*
|
|
* Void SetTopProvider (
|
|
* PConnection top_provider)
|
|
*
|
|
* Functional Description:
|
|
* This member function is used to change the identity of the Top Provider
|
|
* in an existing channel. The only time this will really occur is when
|
|
* a provider that used to be the Top Provider merges into another
|
|
* domain, and therefore ceases to be the Top Provider.
|
|
*
|
|
* Formal Parameters:
|
|
* top_provider (i)
|
|
* This is a pointer to the new Top Provider.
|
|
*
|
|
* Return Value:
|
|
* None.
|
|
*
|
|
* Side Effects:
|
|
* None.
|
|
*
|
|
* Caveats:
|
|
* None.
|
|
*/
|
|
|
|
/*
|
|
* Channel_Type GetChannelType ()
|
|
*
|
|
* Functional Description:
|
|
* This virtual member function returns the type of the channel. For this
|
|
* class it will be either STATIC_CHANNEL or ASSIGNED_CHANNEL, depending
|
|
* on the value of the channel ID.
|
|
*
|
|
* This member function should be overridden by all classes that inherit
|
|
* from this one so that they return a different type.
|
|
*
|
|
* Formal Parameters:
|
|
* None.
|
|
*
|
|
* Return Value:
|
|
* STATIC_CHANNEL if the channel ID is 1000 or less.
|
|
* ASSIGNED_CHANNEL if the channel ID is greater than 1000.
|
|
*
|
|
* Side Effects:
|
|
* None.
|
|
*
|
|
* Caveats:
|
|
* None.
|
|
*/
|
|
|
|
/*
|
|
* BOOL IsValid ()
|
|
*
|
|
* Functional Description:
|
|
* This function returns TRUE if the channel is still valid, and FALSE if
|
|
* it is ready for deletion. This is a virtual function allowing derived
|
|
* classes to change the way this decision is made.
|
|
*
|
|
* This function will use the information in the domain's channel and
|
|
* attachment lists to validate its own existence. For example, if a
|
|
* channel is owned by a user, and that user detaches, the channel will
|
|
* ask to be deleted.
|
|
*
|
|
* Formal Parameters:
|
|
* None.
|
|
*
|
|
* Return Value:
|
|
* TRUE if channel still valid.
|
|
* FALSE if channel needs to be deleted.
|
|
*
|
|
* Side Effects:
|
|
* None.
|
|
*
|
|
* Caveats:
|
|
* None.
|
|
*/
|
|
|
|
/*
|
|
* CAttachment *GetAttachment ()
|
|
*
|
|
* Functional Description:
|
|
* This function returns a pointer to the attachment that leads to the
|
|
* owner of the channel. Since STATIC and ASSIGNED channels do not have
|
|
* owners, this function will always return NULL.
|
|
*
|
|
* Formal Parameters:
|
|
* None.
|
|
*
|
|
* Return Value:
|
|
* NULL.
|
|
*
|
|
* Side Effects:
|
|
* None.
|
|
*
|
|
* Caveats:
|
|
* None.
|
|
*/
|
|
|
|
/*
|
|
* Void IssueMergeRequest ()
|
|
*
|
|
* Functional Description:
|
|
* This member function causes the Channel object to issue a merge request
|
|
* to the top provider. It will pack the appropriate local information
|
|
* into the command.
|
|
*
|
|
* Formal Parameters:
|
|
* None.
|
|
*
|
|
* Return Value:
|
|
* None.
|
|
*
|
|
* Side Effects:
|
|
* None.
|
|
*
|
|
* Caveats:
|
|
* None.
|
|
*/
|
|
|
|
/*
|
|
* Void ChannelJoinRequest (
|
|
* PCommandTarget originator,
|
|
* UserID uidInitiator,
|
|
* ChannelID channel_id)
|
|
*
|
|
* Functional Description:
|
|
* This function is invoked when a user tries to join the channel
|
|
* associated with a Channel object. The originator will be added to
|
|
* the attachment list if it is not already there.
|
|
*
|
|
* If the user ID passed in is valid (not 0), then a channel join confirm
|
|
* will be issued to the user. Setting the user ID to 0 (zero), inhibits
|
|
* this.
|
|
*
|
|
* Derived classes can override this member function to provide more
|
|
* stringent rules about who can join a channel. This class lets anyone
|
|
* join, as specified in MCS for static and assigned channels.
|
|
*
|
|
* Formal Parameters:
|
|
* originator
|
|
* This is the attachment of the user wishing to join the channel.
|
|
* uidInitiator
|
|
* This is the user ID of the user joining the channel. This can
|
|
* be used for security checking in derived classes if desired.
|
|
* channel_id
|
|
* This is the channel being acted upon.
|
|
*
|
|
* Return Value:
|
|
* None.
|
|
*
|
|
* Side Effects:
|
|
* None.
|
|
*
|
|
* Caveats:
|
|
* None.
|
|
*/
|
|
|
|
/*
|
|
* Void ChannelJoinConfirm (
|
|
* PCommandTarget originator,
|
|
* Result result,
|
|
* UserID uidInitiator,
|
|
* UserID requested_id,
|
|
* ChannelID channel_id)
|
|
*
|
|
* Functional Description:
|
|
* This function performs essentially the same operation as JoinRequest
|
|
* above. The only difference is that the user ID cannot be set to 0
|
|
* to inhibit the re-transmission of the join confirm to the user who
|
|
* is joining the channel.
|
|
*
|
|
* Formal Parameters:
|
|
* originator (i)
|
|
* This is the attachment of the user wishing to join the channel.
|
|
* result (i)
|
|
* This is the result of the previous join request.
|
|
* uidInitiator (i)
|
|
* This is the user ID of the user joining the channel. This can
|
|
* be used for security checking in derived classes if desired.
|
|
* requested_id (i)
|
|
* This is the ID of the channel that the user originally asked to
|
|
* join. The only time this will be different from the channel ID
|
|
* below is if the user asked for channel 0, which is interpreted as
|
|
* a request for an assigned channel.
|
|
* channel_id (i)
|
|
* This is the channel being acted upon.
|
|
*
|
|
* Return Value:
|
|
* None.
|
|
*
|
|
* Side Effects:
|
|
* None.
|
|
*
|
|
* Caveats:
|
|
* None.
|
|
*/
|
|
|
|
/*
|
|
* Void ChannelLeaveRequest (
|
|
* PCommandTarget originator,
|
|
* CChannelIDList *channel_id_list)
|
|
*
|
|
* Functional Description:
|
|
* This member function is used when an attachment needs to be removed
|
|
* from a channel. A leave request will only be received from a lower
|
|
* provider when all attachments at that level have left (this means that
|
|
* the data for the channel no longer needs to be sent downward).
|
|
*
|
|
* If this request results in an empty attachment list a
|
|
* ChannelLeaveRequest will be sent upward to the next higher provider in
|
|
* the domain (unless this is the Top Provider).
|
|
*
|
|
* Formal Parameters:
|
|
* originator (i)
|
|
* This is the attachment to be removed from the channel.
|
|
* channel_id_list (i)
|
|
* This is the list of channels being acted upon.
|
|
*
|
|
* Return Value:
|
|
* None.
|
|
*
|
|
* Side Effects:
|
|
* None.
|
|
*
|
|
* Caveats:
|
|
* None.
|
|
*/
|
|
|
|
/*
|
|
* Void SendDataRequest (
|
|
* PCommandTarget originator,
|
|
* UINT type,
|
|
* PDataPacket data_packet)
|
|
*
|
|
* Functional Description:
|
|
* This function is called when it is necessary to send data through the
|
|
* channel that this Channel object represents. All rules for
|
|
* non-uniform data apply. The data will be forwarded upward toward
|
|
* the Top Provider (unless this is the Top Provider). Data will also
|
|
* be sent immediately downward to all attachments who are joined to
|
|
* the channel, except for the attachment from which the data came.
|
|
*
|
|
* Formal Parameters:
|
|
* originator (i)
|
|
* This is the attachment from which the data came.
|
|
* type (i)
|
|
* Simple or uniform send data request.
|
|
* data_packet (i)
|
|
* This is a pointer to a DataPacket object containing the channel
|
|
* ID, the User ID of the data sender, segmentation flags, priority of
|
|
* the data packet and a pointer to the packet to be sent.
|
|
*
|
|
* Return Value:
|
|
* None.
|
|
*
|
|
* Side Effects:
|
|
* None.
|
|
*
|
|
* Caveats:
|
|
* None.
|
|
*/
|
|
|
|
/*
|
|
* Void SendDataIndication (
|
|
* PCommandTarget originator,
|
|
* UINT type,
|
|
* PDataPacket data_packet)
|
|
*
|
|
* Functional Description:
|
|
* This function is called when it is necessary to send data through the
|
|
* channel that this Channel object represents. The data will be sent
|
|
* downward to all attachments joined to the channel.
|
|
*
|
|
* Formal Parameters:
|
|
* originator (i)
|
|
* This is the attachment from which the data came.
|
|
* type (i)
|
|
* normal or uniform indication.
|
|
* data_packet (i)
|
|
* This is a pointer to a DataPacket object containing the channel
|
|
* ID, the User ID of the data sender, segmentation flags, priority of
|
|
* the data packet and a pointer to the packet to be sent.
|
|
*
|
|
* Return Value:
|
|
* None.
|
|
*
|
|
* Side Effects:
|
|
* None.
|
|
*
|
|
* Caveats:
|
|
* None.
|
|
*/
|
|
|
|
#endif
|