Annotation of libwww/Library/src/HTNet.html, revision 2.24
2.1 frystyk 1: <HTML>
2: <HEAD>
2.17 frystyk 3: <TITLE>Asyncronous Socket Management</TITLE>
2.24 ! frystyk 4: <!-- Changed by: Henrik Frystyk Nielsen, 16-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>
! 137: extern BOOL HTNetCall_addAfter (HTNetCallback *cbf, int status);
! 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>
2.24 ! frystyk 148: extern BOOL HTNetCall_addBefore (HTNetCallback *cbf, int status);
! 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);
2.20 frystyk 212: </PRE>
213:
214: <H3>Duplicate an Existing Object</H3>
215:
216: Creates a new HTNet object as a duplicate of the same request.
217: Returns YES if OK, else NO.
218:
219: <PRE>
220: extern BOOL HTNet_dup (HTNet *src, HTNet **dest);
2.17 frystyk 221: </PRE>
222:
2.23 frystyk 223: <H3>Make an Object Wait</H3>
2.19 frystyk 224:
225: Let a net object wait for a persistent socket. It will be launched
226: from the HTNet_delete() function when the socket gets free.
227:
228: <PRE>
229: extern BOOL HTNet_wait (HTNet *net);
230: </PRE>
231:
2.23 frystyk 232: <H3>Priority Management</H3>
233:
234: Each HTNet object is created with a priority which it inherits from
235: the <A HREF="HTReq.html">Request manager</A>. However, in some
236: stuations it is useful to be to change the current priority after the
237: request has been started. These two functions allow you to do
238: this. The effect will show up the first time (which might be
239: imidiately) the socket blocks and control returns to the event loop.
240: Also have a look at how you can do this before the request is issued
241: in the <A HREF="HTReq.html">request manager</A>.
242:
243: <PRE>
244: extern HTPriority HTNet_priority (HTNet * net);
245: extern BOOL HTNet_setPriority (HTNet * net, HTPriority priority);
246: </PRE>
247:
2.17 frystyk 248: <H3>Delete an Object</H3>
249:
250: Deletes the HTNet object from the list of active requests and calls
251: any registered call back functions IF not the status is HT_IGNORE.
252: This is used if we have internal requests that the app doesn't know
253: about. We also see if we have pending requests that can be started up
254: now when we have a socket free. The callback functions are called in
2.24 ! frystyk 255: the reverse order of which they were registered (last one first);
2.1 frystyk 256:
257: <PRE>
2.17 frystyk 258: extern BOOL HTNet_delete (HTNet * me, int status);
2.1 frystyk 259: </PRE>
260:
2.17 frystyk 261: <H3>Delete ALL HTNet Objects</H3>
2.1 frystyk 262:
2.17 frystyk 263: Deletes all HTNet object that might either be active or pending We DO
2.19 frystyk 264: NOT call the call back functions - A crude way of saying goodbye!
2.1 frystyk 265:
266: <PRE>
2.17 frystyk 267: extern BOOL HTNet_deleteAll (void);
2.1 frystyk 268: </PRE>
2.17 frystyk 269:
270: <H3>Kill a Request</H3>
2.1 frystyk 271:
2.17 frystyk 272: Kill the request by calling the call back function with a request for
273: closing the connection. Does not remove the object. This is done by
274: HTNet_delete() function which is called by the load routine. Returns
275: OK if success, NO on error
2.1 frystyk 276:
277: <PRE>
2.17 frystyk 278: extern BOOL HTNet_kill (HTNet * me);
2.1 frystyk 279: </PRE>
280:
2.17 frystyk 281: <H3>Kill ALL requests</H3>
2.1 frystyk 282:
2.17 frystyk 283: Kills all registered (active+pending) requests by calling the call
284: back function with a request for closing the connection. We do not
285: remove the HTNet object as it is done by HTNet_delete(). Returns OK
286: if success, NO on error
2.1 frystyk 287:
288: <PRE>
2.17 frystyk 289: extern BOOL HTNet_killAll (void);
290: </PRE>
2.1 frystyk 291:
2.17 frystyk 292: <PRE>
293: #endif /* HTNET_H */
2.1 frystyk 294: </PRE>
295:
2.17 frystyk 296: End of declaration module
2.1 frystyk 297: </BODY>
298: </HTML>
299:
300:
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