Coverage report: /home/ellis/.stash/quicklisp/dists/ultralisp/software/trivial-garbage-trivial-garbage-20231019214921/trivial-garbage.lisp

Kind	Covered	All	%
expression	22	75	29.3
branch	0	2	0.0

Key

Not instrumented

Conditionalized out

Executed

Not executed

Both branches taken

One branch taken

Neither branch taken

1

;;;; -*- Mode: LISP; Syntax: ANSI-Common-lisp; Base: 10 -*-

2

;;;; The above modeline is required for Genera. Do not change.

3

;;

4

;;; trivial-garbage.lisp --- Trivial Garbage!

5

;;;

6

;;; This software is placed in the public domain by Luis Oliveira

7

;;; <loliveira@common-lisp.net> and is provided with absolutely no

8

;;; warranty.

9

10

#+xcvb (module ())

11

12

(defpackage #:trivial-garbage

13

(:use #:cl)

14

(:shadow #:make-hash-table)

15

(:nicknames #:tg)

16

(:export #:gc

17

#:make-weak-pointer

18

#:weak-pointer-value

19

#:weak-pointer-p

20

#:make-weak-hash-table

21

#:hash-table-weakness

22

#:finalize

23

#:cancel-finalization)

24

(:documentation

25

"@a[http://common-lisp.net/project/trivial-garbage]{trivial-garbage}

26

provides a portable API to finalizers, weak hash-tables and weak

27

pointers on all major implementations of the Common Lisp

28

programming language. For a good introduction to these

29

data-structures, have a look at

30

@a[http://www.haible.de/bruno/papers/cs/weak/WeakDatastructures-writeup.html]{Weak

31

References: Data Types and Implementation} by Bruno Haible.

32

33

Source code is available at

34

@a[https://github.com/trivial-garbage/trivial-garbage]{github},

35

which you are welcome to use for submitting patches and/or

36

@a[https://github.com/trivial-garbage/trivial-garbage/issues]{bug

37

reports}. Discussion takes place on

38

@a[http://lists.common-lisp.net/cgi-bin/mailman/listinfo/trivial-garbage-devel]{trivial-garbage-devel

39

at common-lisp.net}.

40

41

@a[http://common-lisp.net/project/trivial-garbage/releases/]{Tarball

42

releases} are available, but the easiest way to install this

43

library is via @a[http://www.quicklisp.org/]{Quicklisp}:

44

@code{(ql:quickload :trivial-garbage)}.

45

46

@begin[Weak Pointers]{section}

47

A @em{weak pointer} holds an object in a way that does not prevent

48

it from being reclaimed by the garbage collector. An object

49

referenced only by weak pointers is considered unreachable (or

50

\"weakly reachable\") and so may be collected at any time. When

51

that happens, the weak pointer's value becomes @code{nil}.

52

53

@aboutfun{make-weak-pointer}

54

@aboutfun{weak-pointer-value}

55

@aboutfun{weak-pointer-p}

56

@end{section}

57

58

@begin[Weak Hash-Tables]{section}

59

A @em{weak hash-table} is one that weakly references its keys

60

and/or values. When both key and value are unreachable (or weakly

61

reachable) that pair is reclaimed by the garbage collector.

62

63

@aboutfun{make-weak-hash-table}

64

@aboutfun{hash-table-weakness}

65

@end{section}

66

67

@begin[Finalizers]{section}

68

A @em{finalizer} is a hook that is executed after a given object

69

has been reclaimed by the garbage collector.

70

71

@aboutfun{finalize}

72

@aboutfun{cancel-finalization}

73

@end{section}"))

74

75

(in-package #:trivial-garbage)

76

77

;;;; GC

78

79

(defun gc (&key full verbose)

80

"Initiates a garbage collection. @code{full} forces the collection

81

of all generations, when applicable. When @code{verbose} is

82

@em{true}, diagnostic information about the collection is printed

83

if possible."

84

(declare (ignorable verbose full))

85

#+(or cmu scl) (ext:gc :verbose verbose :full full)

86

#+sbcl (sb-ext:gc :full full)

87

#+allegro (excl:gc (not (null full)))

88

#+(or abcl clisp) (ext:gc)

89

#+ecl (si:gc t)

90

#+openmcl (ccl:gc)

91

#+corman (ccl:gc (if full 3 0))

92

#+lispworks (hcl:gc-generation (if full t 0))

93

#+clasp (gctools:garbage-collect)

94

#+mezzano (mezzano.extensions:gc :full full)

95

#+genera (scl:let-globally ((si:gc-report-stream *standard-output*)

96

(si:gc-reports-enable verbose)

97

(si:gc-ephemeral-reports-enable verbose)

98

(si:gc-warnings-enable verbose))

99

(if full

100

(sys:gc-immediately t)

101

(si:ephemeral-gc-flip))))

102

103

;;;; Weak Pointers

104

105

#+openmcl

106

(defvar *weak-pointers* (cl:make-hash-table :test 'eq :weak :value)

107

"Weak value hash-table mapping between pseudo weak pointers and its values.")

108

109

#+genera

110

(defvar *weak-pointers* (scl:make-hash-table :test 'eq :gc-protect-values nil)

111

"Weak value hash-table mapping between pseudo weak pointers and its values.")

112

113

#+(or allegro openmcl lispworks genera)

114

(defstruct (weak-pointer (:constructor %make-weak-pointer))

115

#-(or openmcl genera) pointer)

116

117

(defun make-weak-pointer (object)

118

"Creates a new weak pointer which points to @code{object}. For

119

portability reasons, @code{object} must not be @code{nil}."

120

(assert (not (null object)))

121

#+sbcl (sb-ext:make-weak-pointer object)

122

#+(or cmu scl) (ext:make-weak-pointer object)

123

#+clisp (ext:make-weak-pointer object)

124

#+abcl (ext:make-weak-reference object)

125

#+ecl (ext:make-weak-pointer object)

126

#+allegro

127

(let ((wv (excl:weak-vector 1)))

128

(setf (svref wv 0) object)

129

(%make-weak-pointer :pointer wv))

130

#+(or openmcl genera)

131

(let ((wp (%make-weak-pointer)))

132

(setf (gethash wp *weak-pointers*) object)

133

wp)

134

#+corman (ccl:make-weak-pointer object)

135

#+lispworks

136

(let ((array (make-array 1 :weak t)))

137

(setf (svref array 0) object)

138

(%make-weak-pointer :pointer array))

139

#+clasp (core:make-weak-pointer object)

140

#+mezzano (mezzano.extensions:make-weak-pointer object))

141

142

#-(or allegro openmcl lispworks genera)

143

(defun weak-pointer-p (object)

144

"Returns @em{true} if @code{object} is a weak pointer and @code{nil}

145

otherwise."

146

#+sbcl (sb-ext:weak-pointer-p object)

147

#+(or cmu scl) (ext:weak-pointer-p object)

148

#+clisp (ext:weak-pointer-p object)

149

#+abcl (typep object 'ext:weak-reference)

150

#+ecl (typep object 'ext:weak-pointer)

151

#+corman (ccl:weak-pointer-p object)

152

#+clasp (core:weak-pointer-valid object)

153

#+mezzano (mezzano.extensions:weak-pointer-p object))

154

155

(defun weak-pointer-value (weak-pointer)

156

"If @code{weak-pointer} is valid, returns its value. Otherwise,

157

returns @code{nil}."

158

#+sbcl (values (sb-ext:weak-pointer-value weak-pointer))

159

#+(or cmu scl) (values (ext:weak-pointer-value weak-pointer))

160

#+clisp (values (ext:weak-pointer-value weak-pointer))

161

#+abcl (values (ext:weak-reference-value weak-pointer))

162

#+ecl (values (ext:weak-pointer-value weak-pointer))

163

#+allegro (svref (weak-pointer-pointer weak-pointer) 0)

164

#+(or openmcl genera) (values (gethash weak-pointer *weak-pointers*))

165

#+corman (ccl:weak-pointer-obj weak-pointer)

166

#+lispworks (svref (weak-pointer-pointer weak-pointer) 0)

167

#+clasp (core:weak-pointer-value weak-pointer)

168

#+mezzano (values (mezzano.extensions:weak-pointer-value object)))

169

170

;;;; Weak Hash-tables

171

172

;;; Allegro can apparently create weak hash-tables with both weak keys

173

;;; and weak values but it's not obvious whether it's an OR or an AND

174

;;; relation. TODO: figure that out.

175

176

(defun weakness-keyword-arg (weakness)

177

(declare (ignorable weakness))

178

#+(or sbcl abcl clasp ecl-weak-hash mezzano) :weakness

179

#+(or clisp openmcl) :weak

180

#+lispworks :weak-kind

181

#+allegro (case weakness (:key :weak-keys) (:value :values))

182

#+cmu :weak-p

183

#+genera :gc-protect-values)

184

185

(defvar *weakness-warnings* '()

186

"List of weaknesses that have already been warned about this

187

session. Used by `weakness-missing'.")

188

189

(defun weakness-missing (weakness errorp)

190

"Signal an error or warning, depending on ERRORP, about lack of Lisp

191

support for WEAKNESS."

192

(cond (errorp

193

(error "Your Lisp does not support weak ~(~A~) hash-tables."

194

weakness))

195

((member weakness *weakness-warnings*) nil)

196

(t (push weakness *weakness-warnings*)

197

(warn "Your Lisp does not support weak ~(~A~) hash-tables."

198

weakness))))

199

200

(defun weakness-keyword-opt (weakness errorp)

201

(declare (ignorable errorp))

202

(ecase weakness

203

(:key

204

#+(or lispworks sbcl abcl clasp clisp openmcl ecl-weak-hash mezzano) :key

205

#+(or allegro cmu) t

206

#-(or lispworks sbcl abcl clisp openmcl allegro cmu ecl-weak-hash clasp mezzano)

207

(weakness-missing weakness errorp))

208

(:value

209

#+allegro :weak

210

#+(or clisp openmcl sbcl abcl lispworks cmu ecl-weak-hash mezzano) :value

211

#+genera nil

212

#-(or allegro clisp openmcl sbcl abcl lispworks cmu ecl-weak-hash mezzano genera)

213

(weakness-missing weakness errorp))

214

(:key-or-value

215

#+(or clisp sbcl abcl cmu mezzano) :key-or-value

216

#+lispworks :either

217

#-(or clisp sbcl abcl lispworks cmu mezzano)

218

(weakness-missing weakness errorp))

219

(:key-and-value

220

#+(or clisp abcl sbcl cmu ecl-weak-hash mezzano) :key-and-value

221

#+lispworks :both

222

#-(or clisp sbcl abcl lispworks cmu ecl-weak-hash mezzano)

223

(weakness-missing weakness errorp))))

224

225

(defun make-weak-hash-table (&rest args &key weakness (weakness-matters t)

226

#+openmcl (test #'eql)

227

&allow-other-keys)

228

"Returns a new weak hash table. In addition to the standard

229

arguments accepted by @code{cl:make-hash-table}, this function adds

230

extra keywords: @code{:weakness} being the kind of weak table it

231

should create, and @code{:weakness-matters} being whether an error

232

should be signalled when that weakness isn't available (the default

233

is to signal an error). @code{weakness} can be one of @code{:key},

234

@code{:value}, @code{:key-or-value}, @code{:key-and-value}.

235

236

If @code{weakness} is @code{:key} or @code{:value}, an entry is

237

kept as long as its key or value is reachable, respectively. If

238

@code{weakness} is @code{:key-or-value} or @code{:key-and-value},

239

an entry is kept if either or both of its key and value are

240

reachable, respectively.

241

242

@code{tg::make-hash-table} is available as an alias for this

243

function should you wish to import it into your package and shadow

244

@code{cl:make-hash-table}."

245

(remf args :weakness)

246

(remf args :weakness-matters)

247

(if weakness

248

(let ((arg (weakness-keyword-arg weakness))

249

(opt (weakness-keyword-opt weakness weakness-matters)))

250

(apply #-genera #'cl:make-hash-table #+genera #'scl:make-hash-table

251

#+openmcl :test #+openmcl (if (eq opt :key) #'eq test)

252

#+clasp :test #+clasp #'eq

253

(if arg

254

(list* arg opt args)

255

args)))

256

(apply #'cl:make-hash-table args)))

257

258

;;; If you want to use this function to override CL:MAKE-HASH-TABLE,

259

;;; it's necessary to shadow-import it. For example:

260

;;;

261

;;; (defpackage #:foo

262

;;; (:use #:common-lisp #:trivial-garbage)

263

;;; (:shadowing-import-from #:trivial-garbage #:make-hash-table))

264

;;;

265

(defun make-hash-table (&rest args)

266

(apply #'make-weak-hash-table args))

267

268

(defun hash-table-weakness (ht)

269

"Returns one of @code{nil}, @code{:key}, @code{:value},

270

@code{:key-or-value} or @code{:key-and-value}."

271

#-(or allegro sbcl abcl clisp cmu openmcl lispworks

272

ecl-weak-hash clasp mezzano genera)

273

(declare (ignore ht))

274

;; keep this first if any of the other lisps bugously insert a NIL

275

;; for the returned (values) even when *read-suppress* is NIL (e.g. clisp)

276

#.(if (find :sbcl *features*)

277

(if (find-symbol "HASH-TABLE-WEAKNESS" "SB-EXT")

278

(read-from-string "(sb-ext:hash-table-weakness ht)")

279

nil)

280

(values))

281

#+abcl (sys:hash-table-weakness ht)

282

#+ecl-weak-hash (ext:hash-table-weakness ht)

283

#+allegro (cond ((excl:hash-table-weak-keys ht) :key)

284

((eq (excl:hash-table-values ht) :weak) :value))

285

#+clisp (ext:hash-table-weak-p ht)

286

#+cmu (let ((weakness (lisp::hash-table-weak-p ht)))

287

(if (eq t weakness) :key weakness))

288

#+openmcl (ccl::hash-table-weak-p ht)

289

#+lispworks (system::hash-table-weak-kind ht)

290

#+clasp (core:hash-table-weakness ht)

291

#+mezzano (mezzano.extensions:hash-table-weakness ht)

292

#+genera (if (null (getf (cli::basic-table-options ht) :gc-protect-values t))

293

:value

294

nil))

295

296

;;;; Finalizers

297

298

;;; Note: Lispworks can't finalize gensyms.

299

300

#+(or allegro clisp lispworks openmcl)

301

(defvar *finalizers*

302

(cl:make-hash-table :test 'eq

303

#+allegro :weak-keys #+:allegro t

304

#+(or clisp openmcl) :weak

305

#+lispworks :weak-kind

306

#+(or clisp openmcl lispworks) :key)

307

"Weak hashtable that holds registered finalizers.")

308

309

#+corman

310

(progn

311

(defvar *finalizers* '()

312

"Weak alist that holds registered finalizers.")

313

314

(defvar *finalizers-cs* (threads:allocate-critical-section)))

315

316

#+lispworks

317

(progn

318

(hcl:add-special-free-action 'free-action)

319

(defun free-action (object)

320

(let ((finalizers (gethash object *finalizers*)))

321

(unless (null finalizers)

322

(mapc #'funcall finalizers)))))

323

324

#+mezzano

325

(progn

326

(defvar *finalizers*

327

(cl:make-hash-table :test 'eq :weakness :key)

328

"Weak hashtable that holds registered finalizers.")

329

(defvar *finalizers-lock* (mezzano.supervisor:make-mutex '*finalizers-lock*)))

330

331

;;; Note: ECL bytecmp does not perform escape analysis and unused

332

;;; variables are not optimized away from its lexenv. That leads to

333

;;; closing over whole definition lexenv. That's why we define

334

;;; EXTEND-FINALIZER-FN which defines lambda outside the lexical scope

335

;;; of FINALIZE (which inludes object) - to prevent closing over

336

;;; finalized object. This problem does not apply to C compiler.

337

338

#+ecl

339

(defun extend-finalizer-fn (old-fn new-fn)

340

(if (null old-fn)

341

(lambda (obj)

342

(declare (ignore obj))

343

(funcall new-fn))

344

(lambda (obj)

345

(declare (ignore obj))

346

(funcall new-fn)

347

(funcall old-fn nil))))

348

349

(defun finalize (object function)

350

"Pushes a new @code{function} to the @code{object}'s list of

351

finalizers. @code{function} should take no arguments. Returns

352

@code{object}.

353

354

@b{Note:} @code{function} should not attempt to look at

355

@code{object} by closing over it because that will prevent it from

356

being garbage collected."

357

#+genera (declare (ignore object function))

358

#+(or cmu scl) (ext:finalize object function)

359

#+sbcl (sb-ext:finalize object function :dont-save t)

360

#+abcl (ext:finalize object function)

361

#+ecl (let* ((old-fn (ext:get-finalizer object))

362

(new-fn (extend-finalizer-fn old-fn function)))

363

(ext:set-finalizer object new-fn)

364

object)

365

#+allegro

366

(progn

367

(push (excl:schedule-finalization

368

object (lambda (obj) (declare (ignore obj)) (funcall function)))

369

(gethash object *finalizers*))

370

object)

371

   #+clasp (progn (gctools:finalize object (lambda (obj) (declare (ignore obj)) (funcall function))) object)

372

#+clisp

373

;; The CLISP code used to be a bit simpler but we had to workaround

374

;; a bug regarding the interaction between GC and weak hashtables.

375

;; See <http://article.gmane.org/gmane.lisp.clisp.general/11028>

376

;; and <http://article.gmane.org/gmane.lisp.cffi.devel/994>.

377

(multiple-value-bind (finalizers presentp)

378

(gethash object *finalizers* (cons 'finalizers nil))

379

(unless presentp

380

(setf (gethash object *finalizers*) finalizers)

381

(ext:finalize object (lambda (obj)

382

(declare (ignore obj))

383

(mapc #'funcall (cdr finalizers)))))

384

(push function (cdr finalizers))

385

object)

386

#+openmcl

387

(progn

388

(ccl:terminate-when-unreachable

389

object (lambda (obj) (declare (ignore obj)) (funcall function)))

390

;; store number of finalizers

391

(incf (gethash object *finalizers* 0))

392

object)

393

#+corman

394

(flet ((get-finalizers (obj)

395

(assoc obj *finalizers* :test #'eq :key #'ccl:weak-pointer-obj)))

396

(threads:with-synchronization *finalizers-cs*

397

(let ((pair (get-finalizers object)))

398

(if (null pair)

399

(push (list (ccl:make-weak-pointer object) function) *finalizers*)

400

(push function (cdr pair)))))

401

(ccl:register-finalization

402

object (lambda (obj)

403

(threads:with-synchronization *finalizers-cs*

404

(mapc #'funcall (cdr (get-finalizers obj)))

405

(setq *finalizers*

406

(delete obj *finalizers*

407

:test #'eq :key #'ccl:weak-pointer-obj)))))

408

object)

409

#+lispworks

410

(progn

411

(let ((finalizers (gethash object *finalizers*)))

412

(unless finalizers

413

(hcl:flag-special-free-action object))

414

(setf (gethash object *finalizers*)

415

(cons function finalizers)))

416

object)

417

#+mezzano

418

(mezzano.supervisor:with-mutex (*finalizers-lock*)

419

(let ((finalizer-key (gethash object *finalizers*)))

420

(unless finalizer-key

421

(setf finalizer-key

422

(mezzano.extensions:make-weak-pointer

423

object

424

:finalizer (lambda ()

425

                             (let ((finalizers (mezzano.supervisor:with-mutex (*finalizers-lock*)

426

(prog1

427

                                                     (gethash finalizer-key *finalizers*)

428

                                                   (remhash finalizer-key *finalizers*)))))

429

(mapc #'funcall finalizers)))))

430

(setf (gethash object *finalizers*) finalizer-key))

431

(push function (gethash finalizer-key *finalizers*)))

432

;; Make sure the object doesn't actually get captured by the finalizer lambda.

433

(prog1 object

434

(setf object nil)))

435

#+genera

436

(error "Finalizers are not available in Genera."))

437

438

(defun cancel-finalization (object)

439

"Cancels all of @code{object}'s finalizers, if any."

440

#+genera (declare (ignore object))

441

#+cmu (ext:cancel-finalization object)

442

#+scl (ext:cancel-finalization object nil)

443

#+sbcl (sb-ext:cancel-finalization object)

444

#+abcl (ext:cancel-finalization object)

445

#+ecl (ext:set-finalizer object nil)

446

#+allegro

447

(progn

448

(mapc #'excl:unschedule-finalization

449

(gethash object *finalizers*))

450

(remhash object *finalizers*))

451

#+clasp (gctools:definalize object)

452

#+clisp

453

(multiple-value-bind (finalizers present-p)

454

(gethash object *finalizers*)

455

(when present-p

456

(setf (cdr finalizers) nil))

457

(remhash object *finalizers*))

458

#+openmcl

459

(let ((count (gethash object *finalizers*)))

460

(unless (null count)

461

(dotimes (i count)

462

(ccl:cancel-terminate-when-unreachable object))))

463

#+corman

464

(threads:with-synchronization *finalizers-cs*

465

(setq *finalizers*

466

(delete object *finalizers* :test #'eq :key #'ccl:weak-pointer-obj)))

467

#+lispworks

468

(progn

469

(remhash object *finalizers*)

470

(hcl:flag-not-special-free-action object))

471

#+mezzano

472

(mezzano.supervisor:with-mutex (*finalizers-lock*)

473

(let ((finalizer-key (gethash object *finalizers*)))

474

(when finalizer-key

475

(setf (gethash finalizer-key *finalizers*) '()))))

476

#+genera

477

(error "Finalizers are not available in Genera."))