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/*
* 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
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