]>
Commit | Line | Data |
---|---|---|
edce4d98 | 1 | |
2 | /* | |
c8be6d7b | 3 | * $Id: clientStream.cc,v 1.2 2002/09/24 10:46:43 robertc Exp $ |
edce4d98 | 4 | * |
5 | * DEBUG: section 87 Client-side Stream routines. | |
6 | * AUTHOR: Robert Collins | |
7 | * | |
8 | * SQUID Web Proxy Cache http://www.squid-cache.org/ | |
9 | * ---------------------------------------------------------- | |
10 | * | |
11 | * Squid is the result of efforts by numerous individuals from | |
12 | * the Internet community; see the CONTRIBUTORS file for full | |
13 | * details. Many organizations have provided support for Squid's | |
14 | * development; see the SPONSORS file for full details. Squid is | |
15 | * Copyrighted (C) 2001 by the Regents of the University of | |
16 | * California; see the COPYRIGHT file for full details. Squid | |
17 | * incorporates software developed and/or copyrighted by other | |
18 | * sources; see the CREDITS file for full details. | |
19 | * | |
20 | * This program is free software; you can redistribute it and/or modify | |
21 | * it under the terms of the GNU General Public License as published by | |
22 | * the Free Software Foundation; either version 2 of the License, or | |
23 | * (at your option) any later version. | |
24 | * | |
25 | * This program is distributed in the hope that it will be useful, | |
26 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
27 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
28 | * GNU General Public License for more details. | |
29 | * | |
30 | * You should have received a copy of the GNU General Public License | |
31 | * along with this program; if not, write to the Free Software | |
32 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA. | |
33 | * | |
34 | */ | |
35 | ||
36 | /* | |
37 | * A client Stream is a uni directional pipe, with the usual non-blocking | |
38 | * asynchronous approach present elsewhere in squid. | |
39 | * | |
40 | * Each pipe node has a data push function, and a data request function. | |
41 | * This limits flexability - the data flow is no longer assembled at each | |
42 | * step. | |
43 | * | |
44 | * An alternative approach is to pass each node in the pipe the call- | |
45 | * back to use on each IO call. This allows the callbacks to be changed | |
46 | * very easily by a participating node, but requires more maintenance | |
47 | * in each node (store the call back to the msot recent IO request in | |
48 | * the nodes context.) Such an approach also prevents dynamically | |
49 | * changing the pipeline from outside without an additional interface | |
50 | * method to extract the callback and context from the next node. | |
51 | * | |
52 | * One important characteristic of the stream is that the readfunc | |
53 | * on the terminating node, and the callback on the first node | |
54 | * will be NULL, and never used. | |
55 | */ | |
56 | ||
57 | #include "squid.h" | |
c8be6d7b | 58 | #include "clientStream.h" |
edce4d98 | 59 | |
60 | CBDATA_TYPE(clientStreamNode); | |
61 | ||
62 | /* | |
63 | * TODO: rather than each node undeleting the next, have a clientStreamDelete | |
64 | * that walks the list | |
65 | */ | |
66 | ||
67 | /* | |
68 | * clientStream quick notes: | |
69 | * | |
70 | * Each node including the HEAD of the clientStream has a cbdataReference | |
71 | * held by the stream. Freeing the stream then removes that reference | |
72 | * and cbdataFrees every node. | |
73 | * Any node with other References, and all nodes downstream will only | |
74 | * free when those references are released. | |
75 | * Stream nodes MAY hold references to the data member of the node. | |
76 | * | |
77 | * Specifically - on creation no reference is made. | |
78 | * If you pass a data variable to a node, give it an initial reference. | |
79 | * If the data member is non-null on FREE, cbdataFree WILL be called. | |
80 | * This you must never call cbdataFree on your own context without | |
81 | * explicitly setting the stream node data member to NULL and | |
82 | * cbdataReferenceDone'ing it. | |
83 | * | |
84 | * No data member may hold a reference to it's stream node. | |
85 | * The stream guarantees that DETACH will be called before | |
86 | * freeing the node, alowing data members to cleanup. | |
87 | * | |
88 | * If a node's data holds a reference to something that needs to | |
89 | * free the stream a circular reference list will occur. | |
90 | * This results no data being freed until that reference is removed. | |
91 | * One way to accomplish this is to explicitly remove the | |
92 | * data from your own node before freeing the stream. | |
93 | * | |
94 | * (i.e. | |
95 | * mycontext = this->data; | |
96 | * cbdataReferenceDone (mycontext); | |
97 | * clientStreamFreeLinst (this->head); | |
98 | * cbdataFree (mycontext); | |
99 | * return; | |
100 | */ | |
101 | ||
102 | /* Local functions */ | |
103 | static FREE clientStreamFree; | |
104 | ||
105 | clientStreamNode * | |
106 | clientStreamNew(CSR * readfunc, CSCB * callback, CSD * detach, CSS * status, | |
107 | void *data) | |
108 | { | |
109 | clientStreamNode *temp; | |
110 | CBDATA_INIT_TYPE_FREECB(clientStreamNode, clientStreamFree); | |
111 | temp = cbdataAlloc(clientStreamNode); | |
112 | temp->readfunc = readfunc; | |
113 | temp->callback = callback; | |
114 | temp->detach = detach; | |
115 | temp->status = status; | |
116 | temp->data = data; | |
117 | return temp; | |
118 | } | |
119 | ||
120 | /* | |
121 | * Initialise a client Stream. | |
122 | * list is the stream | |
123 | * func is the read function for the head | |
124 | * callback is the callback for the tail | |
125 | * tailbuf and taillen are the initial buffer and length for the tail. | |
126 | */ | |
127 | void | |
128 | clientStreamInit(dlink_list * list, CSR * func, CSD * rdetach, CSS * readstatus, | |
129 | void *readdata, CSCB * callback, CSD * cdetach, void *callbackdata, | |
c8be6d7b | 130 | StoreIOBuffer tailBuffer) |
edce4d98 | 131 | { |
132 | clientStreamNode *temp = clientStreamNew(func, NULL, rdetach, readstatus, | |
133 | readdata); | |
134 | dlinkAdd(temp, &temp->node, list); | |
135 | cbdataReference(temp); | |
136 | temp->head = list; | |
137 | clientStreamInsertHead(list, NULL, callback, cdetach, NULL, callbackdata); | |
138 | temp = list->tail->data; | |
c8be6d7b | 139 | temp->readBuffer = tailBuffer; |
edce4d98 | 140 | } |
141 | ||
142 | /* | |
143 | * Doesn't actually insert at head. Instead it inserts one *after* | |
144 | * head. This is because HEAD is a special node, as is tail | |
145 | * This function is not suitable for inserting the real HEAD. | |
146 | * TODO: should we always initalise the buffers and length, to | |
147 | * allow safe insertion of elements in the downstream cycle? | |
148 | */ | |
149 | void | |
150 | clientStreamInsertHead(dlink_list * list, CSR * func, CSCB * callback, | |
151 | CSD * detach, CSS * status, void *data) | |
152 | { | |
153 | clientStreamNode *temp; | |
154 | ||
155 | /* test preconditions */ | |
156 | assert(list != NULL); | |
157 | assert(list->head); | |
158 | temp = clientStreamNew(func, callback, detach, status, data); | |
159 | temp->head = list; | |
c8be6d7b | 160 | debug(87, 3) |
edce4d98 | 161 | ("clientStreamInsertHead: Inserted node %p with data %p after head\n", |
162 | temp, data); | |
163 | dlinkAddAfter(temp, &temp->node, list->head, list); | |
164 | cbdataReference(temp); | |
165 | } | |
166 | ||
167 | /* | |
168 | * Callback the next node the in chain with it's requested data | |
169 | */ | |
170 | void | |
171 | clientStreamCallback(clientStreamNode * this, clientHttpRequest * http, | |
c8be6d7b | 172 | HttpReply * rep, StoreIOBuffer replyBuffer) |
edce4d98 | 173 | { |
174 | clientStreamNode *next; | |
175 | assert(this && http && this->node.next); | |
176 | next = this->node.next->data; | |
177 | ||
178 | debug(87, | |
179 | 3) ("clientStreamCallback: Calling %p with cbdata %p from node %p\n", | |
180 | next->callback, next->data, this); | |
c8be6d7b | 181 | next->callback(next, http, rep, replyBuffer); |
edce4d98 | 182 | } |
183 | ||
184 | /* | |
185 | * Call the previous node in the chain to read some data | |
186 | */ | |
187 | void | |
188 | clientStreamRead(clientStreamNode * this, clientHttpRequest * http, | |
c8be6d7b | 189 | StoreIOBuffer readBuffer) |
edce4d98 | 190 | { |
191 | /* place the parameters on the 'stack' */ | |
192 | clientStreamNode *prev; | |
193 | assert(this && http && this->node.prev); | |
194 | prev = this->node.prev->data; | |
195 | ||
196 | debug(87, 3) ("clientStreamRead: Calling %p with cbdata %p from node %p\n", | |
197 | prev->readfunc, prev->data, this); | |
c8be6d7b | 198 | this->readBuffer = readBuffer; |
edce4d98 | 199 | prev->readfunc(prev, http); |
200 | } | |
201 | ||
202 | /* | |
203 | * Detach from the stream - only allowed for terminal members | |
204 | */ | |
205 | void | |
206 | clientStreamDetach(clientStreamNode * this, clientHttpRequest * http) | |
207 | { | |
208 | clientStreamNode *prev = NULL; | |
209 | clientStreamNode *temp = this; | |
210 | ||
211 | if (this->node.prev) { | |
212 | prev = this->node.prev->data; | |
213 | } | |
214 | assert(this->node.next == NULL); | |
215 | debug(87, 3) ("clientStreamDetach: Detaching node %p\n", this); | |
216 | /* And clean up this node */ | |
217 | /* ESI TODO: push refcount class through to head */ | |
218 | cbdataReferenceDone(temp); | |
219 | cbdataFree(this); | |
220 | /* and tell the prev that the detach has occured */ | |
221 | /* | |
222 | * We do it in this order so that the detaching node is always | |
223 | * at the end of the list | |
224 | */ | |
225 | if (prev) { | |
226 | debug(87, 3) ("clientStreamDetach: Calling %p with cbdata %p\n", | |
227 | prev->detach, prev->data); | |
228 | prev->detach(prev, http); | |
229 | } | |
230 | } | |
231 | ||
232 | /* | |
233 | * Abort the stream - detach every node in the pipeline. | |
234 | */ | |
235 | void | |
236 | clientStreamAbort(clientStreamNode * this, clientHttpRequest * http) | |
237 | { | |
238 | dlink_list *list; | |
239 | ||
240 | assert(this != NULL); | |
241 | assert(http != NULL); | |
242 | list = this->head; | |
243 | debug(87, 3) ("clientStreamAbort: Aborting stream with tail %p\n", | |
244 | list->tail); | |
245 | if (list->tail) { | |
246 | clientStreamDetach(list->tail->data, http); | |
247 | } | |
248 | } | |
249 | ||
250 | /* | |
251 | * Call the upstream node to find it's status | |
252 | */ | |
253 | clientStream_status_t | |
254 | clientStreamStatus(clientStreamNode * this, clientHttpRequest * http) | |
255 | { | |
256 | clientStreamNode *prev; | |
257 | assert(this && http && this->node.prev); | |
258 | prev = this->node.prev->data; | |
259 | return prev->status(prev, http); | |
260 | } | |
261 | ||
262 | /* Local function bodies */ | |
263 | void | |
264 | clientStreamFree(void *foo) | |
265 | { | |
266 | clientStreamNode *this = foo; | |
267 | ||
268 | debug(87, 3) ("Freeing clientStreamNode %p\n", this); | |
269 | if (this->data) { | |
270 | cbdataFree(this->data); | |
271 | } | |
272 | if (this->node.next || this->node.prev) { | |
273 | dlinkDelete(&this->node, this->head); | |
274 | } | |
275 | } |