-
Notifications
You must be signed in to change notification settings - Fork 12
/
rudel-transport-util.el
555 lines (474 loc) · 17.1 KB
/
rudel-transport-util.el
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
;;; rudel-transport-util.el --- Utility functions for Rudel transport functionality
;;
;; Copyright (C) 2009, 2010 Jan Moringen
;;
;; Author: Jan Moringen <scymtym@users.sourceforge.net>
;; Keywords: rudel, backend, transport, utility, miscellaneous
;; X-RCS: $Id:$
;;
;; This file is part of Rudel.
;;
;; Rudel is free software: you can redistribute it and/or modify it
;; under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;;
;; Rudel is distributed in the hope that it will be useful, but
;; WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
;; General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with Rudel. If not, see <http://www.gnu.org/licenses>.
;;; Commentary:
;;
;; This file contains utility functions for implementing Rudel
;; transport functionality. In particular, several transport filter
;; classes for common task are available:
;;
;; + `rudel-transport-filter'
;; + `rudel-assembling-transport-filter'
;; + `rudel-parsing-transport-filter'
;; + `rudel-injecting-transport-filter'
;; + `rudel-buffering-transport-filter'
;; + `rudel-collecting-transport-filter'
;; + `rudel-progress-reporting-transport-filter'
;;; History:
;;
;; 0.3 - Collecting transport filter
;;
;; 0.2 - Progress reporting transport filter
;;
;; 0.1 - Initial version
;;; Code:
;;
(require 'rudel-errors) ;; for `rudel-error'
(require 'rudel-transport)
;;; Error conditions
;;
;; rudel-invalid-state
(intern "rudel-invalid-state")
(put 'rudel-invalid-state 'error-conditions
'(error
rudel-error rudel-invalid-state))
(put 'rudel-invalid-state 'error-message
"Operation invalid for current state.")
;;; Class rudel-transport-filter
;;
(defclass rudel-transport-filter (rudel-transport)
((transport :initarg :transport
:type rudel-transport
:documentation
"Transport object that performs the send and
receive operations this filter builds upon.") ;; TODO should be read only
(filter :initarg :filter
:type (or null function)
:initform nil
:reader rudel-filter
:writer rudel-set-filter
:documentation
"Function that is called when data is received.")
(sentinel :initarg :sentinel
:type (or null function)
:initform nil
:reader rudel-sentinel
:writer rudel-set-sentinel
:documentation
"Function that is called when the status of the
transport changes."))
"This class is a base class for transport filters that
transform a bidirectional data stream as it passes through them."
:abstract t)
(defmethod slot-missing ((this rudel-transport-filter)
slot-name operation &optional new-value)
"Make slots of underlying transport available as virtual slots of THIS."
(cond
((and (or (eq slot-name :root-transport)
(eq slot-name 'root-transport))
(eq operation 'oref))
(with-slots (transport) this
(if (rudel-transport-filter-child-p transport)
(oref transport :root-transport)
transport)))
((eq operation 'oref)
(slot-value (oref this :transport) slot-name))
((eq operation 'oset)
(set-slot-value (oref this :transport) slot-name new-value)))
)
(defmethod no-applicable-method ((this rudel-transport-filter)
method &rest args)
"Make methods of underlying transport callable as virtual methods of THIS."
(apply method (oref this :transport) (rest args)))
;;; Class rudel-assembling-transport-filter
;;
(defclass rudel-assembling-transport-filter (rudel-transport-filter)
((buffer :initarg :buffer
:type list
:initform nil
:documentation
"Stores message fragments until complete
messages can be assembled.")
(assembly-function :initarg :assembly-function
:type function
:reader rudel-assembly-function
:writer rudel-set-assembly-function
:documentation
"Function that is called to assemble
message fragments into complete messages.")
(fragment-function :initarg :fragment-function
:type (or null function)
:initform nil
:reader rudel-fragment-function
:writer rudel-set-fragment-function
:documentation
"Function that is called to fragment
complex messages into fragments. If the value is nil, messages
are sent unmodified."))
"Objects of this class assemble received message fragments into
complete messages by calling an assembly function.")
(defmethod initialize-instance ((this rudel-assembling-transport-filter)
slots)
"Initialize THIS using SLOTS and install suitable handlers."
;; Initialize slots.
(when (next-method-p)
(call-next-method))
(with-slots (transport) this
(lexical-let ((this1 this))
;; Install a handler for received data that assembles messages
;; and passes them to the user-provided handler.
(rudel-set-filter
transport
(lambda (data)
;; Assemble complete fragments from stored fragments and
;; possibly incomplete messages in DATA.
(with-slots (buffer assembly-function) this1
(rudel-assemble-fragments data buffer assembly-function))
;; Process all complete messages.
(with-slots (filter) this1
(when filter
(mapc filter data)))))
;; Install a handler for sentinel events and pass them to the
;; user-provided handler.
(rudel-set-sentinel transport (lambda (event)
(with-slots (sentinel) this1
(when sentinel
(funcall sentinel event)))))))
)
(defmethod rudel-send ((this rudel-assembling-transport-filter) data)
"Send DATA using the transport of THIS."
(with-slots (transport fragment-function) this
(if fragment-function
;; If there is a fragment function, fragment DATA and send the
;; individual fragments.
(dolist (fragment (funcall fragment-function data))
(rudel-send transport fragment))
;; If there is no fragment function, just send DATA.
(rudel-send transport data))))
;;; Class rudel-parsing-transport-filter
;;
(defclass rudel-parsing-transport-filter (rudel-transport-filter)
((parse-function :initarg :parse-function
:type function
:initform 'identity
:reader rudel-parse-function
:writer rudel-set-parse-function
:documentation
"Function that is called on each received
piece of data to transform it into a suitable representation.")
(generate-function :initarg :generate-function
:type function
:initform 'identity
:reader rudel-generate-function
:writer rudel-set-generate-function
:documentation
"Function that is called on each outgoing
object to transform it into a string representation."))
"Objects of this class convert sent and received data between
string representations and structured representations by calling
a pair of one parse and one generate function.")
(defmethod initialize-instance ((this rudel-parsing-transport-filter) slots)
"Initialize THIS using SLOTS and install suitable handlers."
;; Initialize slots.
(when (next-method-p)
(call-next-method))
(with-slots (transport) this
(lexical-let ((this1 this))
;; Install a handler for received data that parses messages into
;; structured representations and passes those to the
;; user-provided handler.
(rudel-set-filter
transport
(lambda (message-data)
;; Parse and process all complete messages.
(with-slots (parse-function filter) this1
(when filter
(let ((message (funcall parse-function message-data)))
(funcall filter message))))))
;; Install a handler for sentinel events and pass them to the
;; user-provided handler.
(rudel-set-sentinel transport (lambda (event)
(with-slots (sentinel) this1
(when sentinel
(funcall sentinel event)))))))
)
(defmethod rudel-send ((this rudel-parsing-transport-filter) message)
"Apply generate function to MESSAGE, pass result to transport of THIS."
(with-slots (transport generate-function) this
(rudel-send transport (funcall generate-function message))))
;;; Class rudel-injecting-transport-filter
;;
(defclass rudel-injecting-transport-filter (rudel-transport-filter)
()
"Objects of this class act as transport filters but do not
receive their data from underlying transports. Instead data is
injected by calling `rudel-inject'.")
(defmethod rudel-inject ((this rudel-injecting-transport-filter) data)
"Inject DATA as if it was received from an underlying transport."
(with-slots (filter) this
(when filter
(funcall filter data))))
;;; Class rudel-buffering-transport-filter
;;
(defclass rudel-buffering-transport-filter (rudel-transport-filter)
((queue-in :initarg :queue-in
:type list
:initform nil
:documentation
"Queue of incoming data. Non-empty list only when
the filter is in stopped.")
(queue-out :initarg :queue-out
:type list
:initform nil
:documentation
"Queue of outgoing data. Non-empty list only when
the filter is in stopped.")
(stopped :initarg :stopped
:type boolean
:initform nil
:documentation
"Flag describing whether the filter is currently
stopped."))
"Objects of this class are transport filters that can queue
incoming and outgoing data and process it later.")
(defmethod initialize-instance ((this rudel-buffering-transport-filter)
slots)
"Initialize slots of THIS and install filter in underlying transport."
;; Initialize slots.
(when (next-method-p)
(call-next-method))
(with-slots (transport) this
(lexical-let ((this1 this))
;; Install `rudel-handle' as filter in underlying transport.
(rudel-set-filter transport (lambda (data)
(rudel-handle this1 data)))
;; Install a handler for sentinel events and pass them to the
;; user-provided handler.
(rudel-set-sentinel transport (lambda (event)
(with-slots (sentinel) this1
(when sentinel
(funcall sentinel event)))))))
)
(defmethod rudel-send ((this rudel-buffering-transport-filter) data)
"Send DATA through THIS, queueing when necessary."
(with-slots (transport stopped queue-out) this
(if stopped
;; If stopped, queue DATA.
(push data queue-out)
;; Otherwise send DATA right away.
(rudel-send transport data))))
(defmethod rudel-stop ((this rudel-buffering-transport-filter))
"Stop THIS, queue incoming and out going data."
(with-slots (stopped) this
;; The filter cannot be stopped if it already is stopped.
(when stopped
(signal 'rudel-invalid-state '(stopped)))
;; Set stopped flag.
(setq stopped t))
)
(defmethod rudel-start ((this rudel-buffering-transport-filter))
"Start THIS, process queued incoming and outgoing data."
(with-slots (stopped queue-in queue-out filter) this
;; Send queued outgoing data.
(dolist (data (nreverse queue-out))
(rudel-send this data))
;; Process queued incoming data.
(when filter
(mapc filter (nreverse queue-in)))
;; Clear incoming and outgoing queues, set stopped flag to nil.
(setq queue-in nil
queue-out nil
stopped nil)))
(defmethod rudel-handle ((this rudel-buffering-transport-filter) data)
"Handle DATA."
(with-slots (stopped queue-in filter) this
(if stopped
;; If THIS is stopped, queue DATA.
(push data queue-in)
;; Otherwise call FILTER with DATA right away.
(when filter
(funcall filter data))))
)
;;; Class rudel-collecting-transport-filter
;;
(defclass rudel-collecting-transport-filter (rudel-transport-filter)
((queue :initarg :queue
:type list
:initform nil
:documentation
"Data fragments queued for transmission in the
next chunk.")
(queued-size :initarg :queued-size
:type integer
:initform 0
:documentation
"The size of the queued data.")
(flush-size :initarg :flush-size
:type integer
:initform 1024
:documentation
"Amount of queued data leading to an immediate
transmission.")
(timer :initarg :timer
:type (or null timer)
:initform nil
:documentation
"A timer used to trigger the transmission of
queued data.")
(delay :initarg :delay
:type number
:initform 1
:documentation
"The maximum time to wait before transmitting
queued data even if it is smaller than a complete chunk."))
"Object of this class are transport filters that queue data
sent through them until certain amounts of data are available for
transmission.")
(defmethod initialize-instance ((this rudel-collecting-transport-filter)
slots)
"Initialize slots of THIS and setup filter of underlying transport."
;; Initialize slots of THIS.
(when (next-method-p)
(call-next-method))
(with-slots (transport) this
(lexical-let ((this1 this))
;; Install a filter in the underlying transport.
(rudel-set-filter transport (lambda (data)
(with-slots (filter) this1
(when filter
(funcall filter data)))))
;; Install a handler for sentinel events and pass them to the
;; user-provided handler.
(rudel-set-sentinel transport (lambda (event)
(with-slots (sentinel) this1
(when sentinel
(funcall sentinel event)))))))
)
(defmethod rudel-send ((this rudel-collecting-transport-filter) data)
"Send or enqueue DATA."
(with-slots (transport queue queued-size flush-size) this
;; Enqueue new data.
(push data queue)
(incf queued-size (length data))
;; Transmit data immediately if necessary, otherwise ensure the
;; timer is running.
(if (< queued-size flush-size)
(rudel-maybe-start-timer this)
(rudel-maybe-cancel-timer this)
(rudel-flush this)))
)
(defmethod rudel-flush ((this rudel-collecting-transport-filter))
"Transmit all data queued in THIS immediately."
(with-slots (transport queue queued-size) this
(rudel-send transport (mapconcat #'identity (nreverse queue) ""))
(setq queue nil
queued-size 0)))
(defmethod rudel-maybe-start-timer
((this rudel-collecting-transport-filter))
"Start timer that runs `rudel-flush' when it expires."
;; If necessary, create a timer that runs `rudel-flush' when it
;; expires.
(with-slots (timer delay) this
(unless timer
(lexical-let ((this1 this))
(setq timer (run-at-time
delay nil ;; no repeat
(lambda ()
(rudel-flush this1)
(oset this1 :timer nil)))))))
)
(defmethod rudel-maybe-cancel-timer
((this rudel-collecting-transport-filter))
"Cancel the flush timer of this."
(with-slots (timer) this
(when timer
(cancel-timer timer)
(setq timer nil))))
;;; Class rudel-progress-reporting-transport-filter
;;
(defconst rudel-long-message-threshold 32768
"Threshold for message size, above which messages are sent in
multiple chunks.")
(defconst rudel-long-message-chunk-size 16384
"Chunk size used, when chunking long messages.")
;; TODO have a callback instead of the actual reporter
(defclass rudel-progress-reporting-transport-filter (rudel-transport-filter)
((reporter :initarg :reporter
:documentation
"TODO"))
"TODO")
(defmethod initialize-instance
((this rudel-progress-reporting-transport-filter) slots)
"TODO"
(when (next-method-p)
(call-next-method))
(with-slots (reporter) this
(setq reporter (make-progress-reporter "Sending data " 0.0 1.0)))
;; Install a handler as filter in underlying transport.
(with-slots (transport) this
(lexical-let ((this1 this))
(rudel-set-filter transport (lambda (data)
(with-slots (filter) this1
(when filter
(funcall filter data)))))))
)
(defmethod rudel-send ((this rudel-progress-reporting-transport-filter)
data)
"TODO"
(with-slots (transport reporter) this
(if (>= (length data) rudel-long-message-threshold)
;; For huge messages, chunk the message data and transmit the
;; chunks
(let ((total (/ (length data)
rudel-long-message-chunk-size))
(current 0))
(rudel-loop-chunks data chunk rudel-long-message-chunk-size
(progress-reporter-update reporter (/ (float current) total))
(rudel-send transport chunk)
(incf current))
(progress-reporter-done reporter))
;; Send small messages in one chunk
(rudel-send transport data)))
)
;;; Miscellaneous functions
;;
(defun rudel-transport-make-filter-stack (base specs)
"Construct a filter stack on top of BASE according to SPECS.
SPECS is structured as follows:
SPECS ::= (SPEC*)
SPEC ::= (CLASS KWARG*)
KWARG ::= KEYWORD VALUE
CLASS is the symbol of a class derived from
`rudel-transport-filter' KEYWORD is a keyword and VALUE is an
arbitrary expression and is used unevaluated.
The returned value is the \"top\" of the constructed stack (BASE
being the \"bottom\")."
(let ((current base))
(dolist (spec specs)
(destructuring-bind (class &rest args) spec
(setq current (apply #'make-instance
class
:transport current
args))))
current))
(provide 'rudel-transport-util)
;;; rudel-transport-util.el ends here