Annotation of libwww/Library/src/HTNet.html, revision 2.26
2.1 frystyk 1: <HTML>
2: <HEAD>
2.17 frystyk 3: <TITLE>Asyncronous Socket Management</TITLE>
2.26 ! frystyk 4: <!-- Changed by: Henrik Frystyk Nielsen, 22-Nov-1995 -->
2.1 frystyk 5: </HEAD>
6: <BODY>
2.2 frystyk 7:
2.17 frystyk 8: <H1>Asyncronous Socket Management</H1>
2.1 frystyk 9:
2.5 frystyk 10: <PRE>
11: /*
2.8 frystyk 12: ** (c) COPYRIGHT MIT 1995.
2.5 frystyk 13: ** Please first read the full copyright statement in the file COPYRIGH.
14: */
15: </PRE>
16:
2.1 frystyk 17: This module contains the routines for handling the set of active
2.2 frystyk 18: sockets currently in use by the multithreaded clients. It is an
19: internal module to the Library, the application interface is
2.15 frystyk 20: implemented in the <A HREF="HTEvntrg.html">Event Module</A>. Look for
2.2 frystyk 21: more information in the <A
2.17 frystyk 22: HREF="http://www.w3.org/pub/WWW/Library/User/Architecture/">
2.2 frystyk 23: Multithread Specifications</A>. <P>
2.1 frystyk 24:
2.17 frystyk 25: This module is implemented by <A HREF="HTNet.c">HTNet.c</A>, and it is
26: a part of the <A HREF="http://www.w3.org/pub/WWW/Library/">W3C
27: Reference Library</A>.
2.1 frystyk 28:
29: <PRE>
2.17 frystyk 30: #ifndef HTNET_H
31: #define HTNET_H
2.21 frystyk 32: #include "HTEvntrg.h"
2.17 frystyk 33: #include "HTReq.h"
2.1 frystyk 34: </PRE>
35:
2.17 frystyk 36: <H2>The HTNet Object</H2>
2.1 frystyk 37:
2.17 frystyk 38: The <CODE>HTNet</CODE> object is the core of the request queue
39: management. This object contains information about the socket
40: descriptor, the input read buffer etc. required to identify and
41: service a request. <P>
2.1 frystyk 42:
43: <PRE>
2.18 frystyk 44: typedef struct _HTNet HTNet;
2.1 frystyk 45: </PRE>
46:
2.24 frystyk 47: <H2>Request Call Back Functions</H2>
2.17 frystyk 48:
2.24 frystyk 49: Callback functions can be registered to be called <EM>before</EM> and
50: <EM>after</EM> a request has either been started or has
51: terminated. The following functions are the generic registration
52: mechanisms where we use lists as the basic data container. Then there
53: is two methods for binding a list of callback functions to the set
54: which is called <EM>before</EM> and to the set set which is called
55: <EM>after</EM> <P>
56:
57: In both cases there can be more than one callback function which are
2.17 frystyk 58: called on turn and each callback function can be associated with a
59: status code of the request. For example one callback function can be
60: registered for HT_LOADED, another for HT_ERROR etc.
61:
62: <H3>Register a Request Callback</H3>
2.2 frystyk 63:
2.17 frystyk 64: Register a call back function that is to be called on every
65: termination of a request. Several call back functions can be
66: registered in which case all of them are called in the reverse order
2.24 frystyk 67: of which they were registered (last one first). We name the calling
68: mechansm of calling the functions for the <EM>before</EM> loop and the
69: <EM>after</EM> loop.<P>
70:
71: In case the callback function is registered as being called
72: <EM>after</EM> the request has terminated the result of the request is
73: passed to the fucntion. The status signifies which call back function
74: to call depending of the result of the request. This can be
2.1 frystyk 75:
2.17 frystyk 76: <DL>
77: <DT>HT_ERROR
78: <DD>An error occured
79: <DT>HT_LOADED
80: <DD>The document was loaded
81: <DT>HT_NO_DATA
82: <DD>OK, but no data
83: <DT>HT_RETRY
84: <DD>Retry request after at a later time
2.24 frystyk 85: <DT>HT_REDIRECT
86: <DD>The request has been redirected and we send back the new URL
2.17 frystyk 87: <DT>HT_ALL
88: <DD>All of above
89: </DL>
2.1 frystyk 90:
2.24 frystyk 91: Any callback function any code it likes, but <B>IF NOT</B> the code is
92: <EM>HT_OK</EM>, then the callback loop is stopped. If we are in the
93: <EM>before</EM> loop and a function returns anything else than
94: <EM>HT_OK</EM> then we immediately jump to the <EM>after</EM> loop
95: <B>passing</B> the last return code from the <EM>before</EM> loop.
96:
2.1 frystyk 97: <PRE>
2.23 frystyk 98: typedef int HTNetCallback (HTRequest * request, int status);
2.17 frystyk 99:
2.24 frystyk 100: extern BOOL HTNetCall_add (HTList * list, HTNetCallback *cbf, int status);
2.9 frystyk 101: </PRE>
102:
2.24 frystyk 103: <H3>Delete a single Callbak</H3>
2.9 frystyk 104:
2.24 frystyk 105: Removes a callback function from a list
2.9 frystyk 106:
107: <PRE>
2.24 frystyk 108: extern BOOL HTNetCall_delete (HTList * list, HTNetCallback *cbf);
2.1 frystyk 109: </PRE>
110:
2.24 frystyk 111: <H3>Delete a list of Callbacks</H3>
112:
113: Unregisters all call back functions in the list
114:
115: <PRE>
116: extern BOOL HTNetCall_deleteAll (HTList * list);
117: </PRE>
118:
119: <H3>Call List of Registered Callback Functions</H3>
2.10 frystyk 120:
2.17 frystyk 121: Call all the call back functions registered in the list IF not the
2.24 frystyk 122: status is HT_IGNORE. The callback functions are called in the order
123: of which they were registered. At the moment an application callback
124: function is called, it can free the request object - it is no longer
125: used by the Library. Returns what the last callback function returns
126:
127: <PRE>
128: extern int HTNetCall_execute (HTList * list, HTRequest * request, int status);
129: </PRE>
130:
131: <H3>BEFORE Callbacks</H3>
132:
133: Global set of callback functions BEFORE the request is issued. The
134: list can be NULL.
135:
136: <PRE>
2.25 frystyk 137: extern BOOL HTNetCall_addBefore (HTNetCallback *cbf, int status);
2.24 frystyk 138: extern BOOL HTNet_setBefore (HTList * list);
139: extern HTList * HTNet_before (void);
140: extern int HTNet_callBefore (HTRequest *request, int status);
141: </PRE>
142:
143: <H3>AFTER Callbacks</H3>
144:
145: Global set of callback functions AFTER the request is issued. The list can be NULL
2.10 frystyk 146:
147: <PRE>
2.25 frystyk 148: extern BOOL HTNetCall_addAfter (HTNetCallback *cbf, int status);
2.24 frystyk 149: extern BOOL HTNet_setAfter (HTList * list);
150: extern HTList * HTNet_after (void);
151: extern int HTNet_callAfter (HTRequest *request, int status);
2.10 frystyk 152: </PRE>
153:
2.17 frystyk 154: <H2>Request Queue</H2>
155:
156: The request queue ensures that no more than a fixed number of TCP
157: connections are open at the same time. If more requests are handed to
158: the Library, they are put into the pending queue and initiated when
159: sockets become free.
160:
161: <H3>Number of Simultanous open TCP connections</H3>
2.1 frystyk 162:
2.17 frystyk 163: Set the max number of simultanous sockets. The default value is
2.19 frystyk 164: HT_MAX_SOCKETS which is 6. The number of persistent connections depend
165: on this value as a deadlock can occur if all available sockets a
166: persistent (see the <A HREF="HTDNS.html">DNS Manager</A> for more
167: information on setting the number of persistent connections). The
168: number of persistent connections can never be more than the max number
169: of sockets-2, so letting newmax=2 prevents persistent sockets.
2.1 frystyk 170:
171: <PRE>
2.17 frystyk 172: extern BOOL HTNet_setMaxSocket (int newmax);
173: extern int HTNet_maxSocket (void);
2.1 frystyk 174: </PRE>
175:
2.23 frystyk 176: <H3>List Active Queue</H3>
2.1 frystyk 177:
2.17 frystyk 178: Returns the list of active requests that are currently having an open
2.22 frystyk 179: connection. Returns list of HTNet objects or NULL if
180: error. <CODE>HTNet_idle()</CODE> returns YES if no active sockets are
181: registered.
2.1 frystyk 182:
183: <PRE>
2.17 frystyk 184: extern HTList *HTNet_activeQueue (void);
2.22 frystyk 185: extern BOOL HTNet_idle (void);
2.1 frystyk 186: </PRE>
2.17 frystyk 187:
2.23 frystyk 188: <H3>List Pending Queue</H3>
2.17 frystyk 189:
190: Returns the list of pending requests that are waiting to become
191: active. Returns list of HTNet objects or NULL if error
192:
2.1 frystyk 193: <PRE>
2.17 frystyk 194: extern HTList *HTNet_pendingQueue (void);
2.1 frystyk 195: </PRE>
196:
2.23 frystyk 197: <H2>HTNet Object Methods</H2>
2.17 frystyk 198:
199: These methods are used from within the Request Manager and are not
200: normally to be used outside the Library kernel.
201:
202: <H3>Create an Object</H3>
203:
204: Create a new HTNet object as a new request to be handled. If we have
205: more than HTMaxActive connections already then put this into the
206: pending queue, else start the request by calling the call back
207: function registered with this access method. Returns YES if OK, else
208: NO
209:
210: <PRE>
2.23 frystyk 211: extern BOOL HTNet_new (HTRequest * request);
2.26 ! frystyk 212: </PRE>
! 213:
! 214: <H3>Create an Empty Object</H3>
! 215:
! 216: This function creates a new HTNet object and assigns the socket number
! 217: to it. This is intended to be used when you are going to listen on a
! 218: socket using the HTDoListen() function in HTTCP.c. The function do NOT
! 219: call any of the callback functions. Returns YES if OK, else NO
! 220:
! 221: <PRE>
! 222: extern BOOL HTNet_create (HTRequest * request, SOCKET sockfd);
2.20 frystyk 223: </PRE>
224:
225: <H3>Duplicate an Existing Object</H3>
226:
227: Creates a new HTNet object as a duplicate of the same request.
228: Returns YES if OK, else NO.
229:
230: <PRE>
231: extern BOOL HTNet_dup (HTNet *src, HTNet **dest);
2.17 frystyk 232: </PRE>
233:
2.23 frystyk 234: <H3>Make an Object Wait</H3>
2.19 frystyk 235:
236: Let a net object wait for a persistent socket. It will be launched
237: from the HTNet_delete() function when the socket gets free.
238:
239: <PRE>
240: extern BOOL HTNet_wait (HTNet *net);
241: </PRE>
242:
2.23 frystyk 243: <H3>Priority Management</H3>
244:
245: Each HTNet object is created with a priority which it inherits from
246: the <A HREF="HTReq.html">Request manager</A>. However, in some
247: stuations it is useful to be to change the current priority after the
248: request has been started. These two functions allow you to do
249: this. The effect will show up the first time (which might be
250: imidiately) the socket blocks and control returns to the event loop.
251: Also have a look at how you can do this before the request is issued
252: in the <A HREF="HTReq.html">request manager</A>.
253:
254: <PRE>
255: extern HTPriority HTNet_priority (HTNet * net);
256: extern BOOL HTNet_setPriority (HTNet * net, HTPriority priority);
257: </PRE>
258:
2.17 frystyk 259: <H3>Delete an Object</H3>
260:
261: Deletes the HTNet object from the list of active requests and calls
262: any registered call back functions IF not the status is HT_IGNORE.
263: This is used if we have internal requests that the app doesn't know
264: about. We also see if we have pending requests that can be started up
265: now when we have a socket free. The callback functions are called in
2.24 frystyk 266: the reverse order of which they were registered (last one first);
2.1 frystyk 267:
268: <PRE>
2.17 frystyk 269: extern BOOL HTNet_delete (HTNet * me, int status);
2.1 frystyk 270: </PRE>
271:
2.17 frystyk 272: <H3>Delete ALL HTNet Objects</H3>
2.1 frystyk 273:
2.17 frystyk 274: Deletes all HTNet object that might either be active or pending We DO
2.19 frystyk 275: NOT call the call back functions - A crude way of saying goodbye!
2.1 frystyk 276:
277: <PRE>
2.17 frystyk 278: extern BOOL HTNet_deleteAll (void);
2.1 frystyk 279: </PRE>
2.17 frystyk 280:
281: <H3>Kill a Request</H3>
2.1 frystyk 282:
2.17 frystyk 283: Kill the request by calling the call back function with a request for
284: closing the connection. Does not remove the object. This is done by
285: HTNet_delete() function which is called by the load routine. Returns
286: OK if success, NO on error
2.1 frystyk 287:
288: <PRE>
2.17 frystyk 289: extern BOOL HTNet_kill (HTNet * me);
2.1 frystyk 290: </PRE>
291:
2.17 frystyk 292: <H3>Kill ALL requests</H3>
2.1 frystyk 293:
2.17 frystyk 294: Kills all registered (active+pending) requests by calling the call
295: back function with a request for closing the connection. We do not
296: remove the HTNet object as it is done by HTNet_delete(). Returns OK
297: if success, NO on error
2.1 frystyk 298:
299: <PRE>
2.17 frystyk 300: extern BOOL HTNet_killAll (void);
301: </PRE>
2.1 frystyk 302:
2.17 frystyk 303: <PRE>
304: #endif /* HTNET_H */
2.1 frystyk 305: </PRE>
306:
2.17 frystyk 307: End of declaration module
2.1 frystyk 308: </BODY>
309: </HTML>
310:
311:
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