windows-nt/Source/XPSP1/NT/termsrv/remdsk/rds/t120/h/userchnl.h

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2020-09-26 03:20:57 -05:00
/*
* userchnl.h
*
* Copyright (c) 1993 - 1995 by DataBeam Corporation, Lexington, KY
*
* Abstract:
* This is the interface file for the UserChannel class. Objects of this
* class represent user ID channels in the MCS environment. This class
* inherits most of its behavior from class Channel. In fact, with the
* exception of how user channels are joined, and how merge commands are
* constructed, this class works exactly the same as class Channel.
*
* When a user attaches to a domain, each provider in the path from the
* Top Provider to the user will create an object of this class. Unlike
* static and assigned channels, it is NOT necessary for the user to
* be joined to the channel for the channel to exist. It is perfectly
* legal to have a user channel that no one is joined to.
*
* The major distinguishing characteristic of user channels is that they
* know the user ID of the user they are associated with. They will
* only allow that user to join the channel. Furthermore, when the user
* leaves the usert channel, the LeaveRequest does not return a value
* asking to be deleted. Anyone can send data on a user ID channel.
*
* The merge channel command is constructed slightly differently for user
* channels, so that behavior is overridden here as well.
*
* Caveats:
* None.
*
* Author:
* James P. Galvin, Jr.
*/
#ifndef _USERCHANNEL_
#define _USERCHANNEL_
/*
* This is the class definition for the UserChannel class.
*/
class UserChannel : public Channel
{
public:
UserChannel (
ChannelID channel_id,
CAttachment *user_attachment,
PDomain local_provider,
PConnection top_provider,
CChannelList2 *channel_list,
CAttachmentList *attachment_list);
UserChannel (
ChannelID channel_id,
CAttachment *user_attachment,
PDomain local_provider,
PConnection top_provider,
CChannelList2 *channel_list,
CAttachmentList *attachment_list,
PConnection pConn);
virtual ~UserChannel ();
virtual Channel_Type GetChannelType ();
virtual BOOL IsValid ();
virtual CAttachment *GetAttachment(void);
virtual Void IssueMergeRequest ();
virtual Void ChannelJoinRequest (
CAttachment *originator,
UserID uidInitiator,
ChannelID channel_id);
virtual Void SendDataRequest (
CAttachment *originator,
UINT type,
PDataPacket data_packet);
private:
CAttachment *m_pUserAttachment;
};
typedef UserChannel * PUserChannel;
/*
* UserChannel (
* ChannelID channel_id,
* PCommandTarget user_attachment,
* PDomain local_provider,
* PConnection top_provider,
* PChannelList channel_list,
* PAttachmentList attachment_list)
*
* Functional Description:
* This is the normal constructor for the UserChannel class. It simply
* initializes the instance variables that identify the channel, the local
* provider, the top provider, and the user attachment. The attachment
* list is empty by default (meaning that the user is not yet joined to
* its channel).
*
* Upon successful construction of this object, an attach user confirm
* is automatically issued to the user.
*
* 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.
* user_attachment (i)
* This is the attachment which leads to the user represented by this
* UserChannel object. It does not matter if it is a local attachment
* or a remote attachment. This is used to issue MCS commands (such
* as attach user confirm) to the user.
* local_provider (i)
* This is the identity of the local provider. A UserChannel 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
* UserChannel object when it needs to issue a request to 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.
*/
/*
* UserChannel (
* ChannelID channel_id,
* PCommandTarget user_attachment,
* 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 UserChannel object to be constructed with the
* user already joined to the channel. The initial attachment should be
* the same as the user attachment.
*
* This version of the constructor will not issue an attach user confirm
* or a channel join confirm to the user.
*
* 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.
* user_attachment (i)
* This is the attachment which leads to the user represented by this
* UserChannel object. It does not matter if it is a local attachment
* or a remote attachment. This is used to issue MCS commands (such
* as attach user confirm) to the user.
* local_provider (i)
* This is the identity of the local provider. A UserChannel 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
* UserChannel object when it needs to issue a request to 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.
*/
/*
* ~UserChannel ()
*
* Functional Description:
* This is the UserChannel class destructor. It does nothing at this time.
* The base class constructor takes care of clearing the attachment list.
*
* Formal Parameters:
* None.
*
* 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 always be USER_CHANNEL.
*
* Formal Parameters:
* None.
*
* Return Value:
* USER_CHANNEL
*
* Side Effects:
* None.
*
* Caveats:
* None.
*/
/*
* BOOL IsValid ()
*
* Functional Description:
* This function always returns TRUE since User ID channels are always
* valid (as long as the user is still attached).
*
* Formal Parameters:
* None.
*
* Return Value:
* TRUE
*
* Side Effects:
* None.
*
* Caveats:
* None.
*/
/*
* CAttachment *GetAttachment ()
*
* Functional Description:
* This function is used to retrieve the attachment associated with the
* user represented by this object. This is used by Domain objects when
* it is necessary to send an MCS command to a user, and it needs to know
* how to get it there. That information is currently excapsulated within
* this class.
*
* Formal Parameters:
* None.
*
* Return Value:
* A pointer to the attachment that leads to the user represented by this
* object.
*
* Side Effects:
* None.
*
* Caveats:
* None.
*/
/*
* Void IssueMergeRequest ()
*
* Functional Description:
* This member function causes the UserChannel 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 UserChannel object. The originator of the request
* will only be permitted to join if their user ID matches that of the
* user with which this UserChannel object is associated. If it does,
* then the originator will be permitted to join.
*
* If this provider is not the Top Provider, then the request will be
* forwarded upward to the Top Provider. If this is the Top Provider,
* the a channel join confirm will be issued back to the requesting
* user.
*
* Formal Parameters:
* originator (i)
* This is the attachment of the user wishing to join the channel.
* uidInitiator (i)
* This is the user ID of the user joining the channel. This must
* be the same as the user ID represented by the object, or the
* request will automatically be rejected.
* channel_id (i)
* This is the channel being acted upon.
*
* Return Value:
* None.
*
* Side Effects:
* None.
*
* Caveats:
* None.
*/
/*
* Void SendDataRequest (
* PCommandTarget originator,
* PDataPacket data_packet)
*
* Functional Description:
* This member function handles a send data request on the channel. It
* determines where to send the data. This differs from the base class
* implementation only in that it is unnecessary to send data upward
* if it is known that the user is in the sub-tree of the current
* provider.
*
* Formal Parameters:
* originator (i)
* This is the attachment from which the data originated.
* 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