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