cpython-withatomic / Objects / frameobject.c

The branch '2.4' does not exist.
  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
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
/* Frame object implementation */

#include "Python.h"

#include "compile.h"
#include "frameobject.h"
#include "opcode.h"
#include "structmember.h"

#undef MIN
#undef MAX
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#define MAX(a, b) ((a) > (b) ? (a) : (b))

#define OFF(x) offsetof(PyFrameObject, x)

static PyMemberDef frame_memberlist[] = {
	{"f_back",	T_OBJECT,	OFF(f_back),	RO},
	{"f_code",	T_OBJECT,	OFF(f_code),	RO},
	{"f_builtins",	T_OBJECT,	OFF(f_builtins),RO},
	{"f_globals",	T_OBJECT,	OFF(f_globals),	RO},
	{"f_lasti",	T_INT,		OFF(f_lasti),	RO},
	{"f_restricted",T_INT,		OFF(f_restricted),RO},
	{"f_exc_type",	T_OBJECT,	OFF(f_exc_type)},
	{"f_exc_value",	T_OBJECT,	OFF(f_exc_value)},
	{"f_exc_traceback", T_OBJECT,	OFF(f_exc_traceback)},
	{NULL}	/* Sentinel */
};

static PyObject *
frame_getlocals(PyFrameObject *f, void *closure)
{
	PyFrame_FastToLocals(f);
	Py_INCREF(f->f_locals);
	return f->f_locals;
}

static PyObject *
frame_getlineno(PyFrameObject *f, void *closure)
{
	int lineno;

	if (f->f_trace)
		lineno = f->f_lineno;
	else
		lineno = PyCode_Addr2Line(f->f_code, f->f_lasti);

	return PyInt_FromLong(lineno);
}

/* Setter for f_lineno - you can set f_lineno from within a trace function in
 * order to jump to a given line of code, subject to some restrictions.  Most
 * lines are OK to jump to because they don't make any assumptions about the
 * state of the stack (obvious because you could remove the line and the code
 * would still work without any stack errors), but there are some constructs
 * that limit jumping:
 *
 *  o Lines with an 'except' statement on them can't be jumped to, because
 *    they expect an exception to be on the top of the stack.
 *  o Lines that live in a 'finally' block can't be jumped from or to, since
 *    the END_FINALLY expects to clean up the stack after the 'try' block.
 *  o 'try'/'for'/'while' blocks can't be jumped into because the blockstack
 *    needs to be set up before their code runs, and for 'for' loops the
 *    iterator needs to be on the stack.
 */
static int
frame_setlineno(PyFrameObject *f, PyObject* p_new_lineno)
{
	int new_lineno = 0;		/* The new value of f_lineno */
	int new_lasti = 0;		/* The new value of f_lasti */
	int new_iblock = 0;		/* The new value of f_iblock */
	char *code = NULL;		/* The bytecode for the frame... */
	int code_len = 0;		/* ...and its length */
	char *lnotab = NULL;		/* Iterating over co_lnotab */
	int lnotab_len = 0;		/* (ditto) */
	int offset = 0;			/* (ditto) */
	int line = 0;			/* (ditto) */
	int addr = 0;			/* (ditto) */
	int min_addr = 0;		/* Scanning the SETUPs and POPs */
	int max_addr = 0;		/* (ditto) */
	int delta_iblock = 0;		/* (ditto) */
	int min_delta_iblock = 0;	/* (ditto) */
	int min_iblock = 0;		/* (ditto) */
	int f_lasti_setup_addr = 0;	/* Policing no-jump-into-finally */
	int new_lasti_setup_addr = 0;	/* (ditto) */
	int blockstack[CO_MAXBLOCKS];	/* Walking the 'finally' blocks */
	int in_finally[CO_MAXBLOCKS];	/* (ditto) */
	int blockstack_top = 0;		/* (ditto) */
	int setup_op = 0;               /* (ditto) */

	/* f_lineno must be an integer. */
	if (!PyInt_Check(p_new_lineno)) {
		PyErr_SetString(PyExc_ValueError,
				"lineno must be an integer");
		return -1;
	}

	/* You can only do this from within a trace function, not via
	 * _getframe or similar hackery. */
	if (!f->f_trace)
	{
		PyErr_Format(PyExc_ValueError,
			     "f_lineno can only be set by a trace function");
		return -1;
	}

	/* Fail if the line comes before the start of the code block. */
	new_lineno = (int) PyInt_AsLong(p_new_lineno);
	if (new_lineno < f->f_code->co_firstlineno) {
		PyErr_Format(PyExc_ValueError,
			     "line %d comes before the current code block",
			     new_lineno);
		return -1;
	}

	/* Find the bytecode offset for the start of the given line, or the
	 * first code-owning line after it. */
	PyString_AsStringAndSize(f->f_code->co_lnotab, &lnotab, &lnotab_len);
	addr = 0;
	line = f->f_code->co_firstlineno;
	new_lasti = -1;
	for (offset = 0; offset < lnotab_len; offset += 2) {
		addr += lnotab[offset];
		line += lnotab[offset+1];
		if (line >= new_lineno) {
			new_lasti = addr;
			new_lineno = line;
			break;
		}
	}

	/* If we didn't reach the requested line, return an error. */
	if (new_lasti == -1) {
		PyErr_Format(PyExc_ValueError,
			     "line %d comes after the current code block",
			     new_lineno);
		return -1;
	}

	/* We're now ready to look at the bytecode. */
	PyString_AsStringAndSize(f->f_code->co_code, &code, &code_len);
	min_addr = MIN(new_lasti, f->f_lasti);
	max_addr = MAX(new_lasti, f->f_lasti);

	/* You can't jump onto a line with an 'except' statement on it -
	 * they expect to have an exception on the top of the stack, which
	 * won't be true if you jump to them.  They always start with code
	 * that either pops the exception using POP_TOP (plain 'except:'
	 * lines do this) or duplicates the exception on the stack using
	 * DUP_TOP (if there's an exception type specified).  See compile.c,
	 * 'com_try_except' for the full details.  There aren't any other
	 * cases (AFAIK) where a line's code can start with DUP_TOP or
	 * POP_TOP, but if any ever appear, they'll be subject to the same
	 * restriction (but with a different error message). */
	if (code[new_lasti] == DUP_TOP || code[new_lasti] == POP_TOP) {
		PyErr_SetString(PyExc_ValueError,
		    "can't jump to 'except' line as there's no exception");
		return -1;
	}

	/* You can't jump into or out of a 'finally' block because the 'try'
	 * block leaves something on the stack for the END_FINALLY to clean
	 * up.  So we walk the bytecode, maintaining a simulated blockstack.
	 * When we reach the old or new address and it's in a 'finally' block
	 * we note the address of the corresponding SETUP_FINALLY.  The jump
	 * is only legal if neither address is in a 'finally' block or
	 * they're both in the same one.  'blockstack' is a stack of the
	 * bytecode addresses of the SETUP_X opcodes, and 'in_finally' tracks
	 * whether we're in a 'finally' block at each blockstack level. */
	f_lasti_setup_addr = -1;
	new_lasti_setup_addr = -1;
	memset(blockstack, '\0', sizeof(blockstack));
	memset(in_finally, '\0', sizeof(in_finally));
	blockstack_top = 0;
	for (addr = 0; addr < code_len; addr++) {
		unsigned char op = code[addr];
		switch (op) {
		case SETUP_LOOP:
		case SETUP_EXCEPT:
		case SETUP_FINALLY:
			blockstack[blockstack_top++] = addr;
			in_finally[blockstack_top-1] = 0;
			break;

		case POP_BLOCK:
			assert(blockstack_top > 0);
			setup_op = code[blockstack[blockstack_top-1]];
			if (setup_op == SETUP_FINALLY) {
				in_finally[blockstack_top-1] = 1;
			}
			else {
				blockstack_top--;
			}
			break;

		case END_FINALLY:
			/* Ignore END_FINALLYs for SETUP_EXCEPTs - they exist
			 * in the bytecode but don't correspond to an actual
			 * 'finally' block.  (If blockstack_top is 0, we must
			 * be seeing such an END_FINALLY.) */
			if (blockstack_top > 0) {
				setup_op = code[blockstack[blockstack_top-1]];
				if (setup_op == SETUP_FINALLY) {
					blockstack_top--;
				}
			}
			break;
		}

		/* For the addresses we're interested in, see whether they're
		 * within a 'finally' block and if so, remember the address
		 * of the SETUP_FINALLY. */
		if (addr == new_lasti || addr == f->f_lasti) {
			int i = 0;
			int setup_addr = -1;
			for (i = blockstack_top-1; i >= 0; i--) {
				if (in_finally[i]) {
					setup_addr = blockstack[i];
					break;
				}
			}

			if (setup_addr != -1) {
				if (addr == new_lasti) {
					new_lasti_setup_addr = setup_addr;
				}

				if (addr == f->f_lasti) {
					f_lasti_setup_addr = setup_addr;
				}
			}
		}

		if (op >= HAVE_ARGUMENT) {
			addr += 2;
		}
	}

	/* Verify that the blockstack tracking code didn't get lost. */
	assert(blockstack_top == 0);

	/* After all that, are we jumping into / out of a 'finally' block? */
	if (new_lasti_setup_addr != f_lasti_setup_addr) {
		PyErr_SetString(PyExc_ValueError,
			    "can't jump into or out of a 'finally' block");
		return -1;
	}


	/* Police block-jumping (you can't jump into the middle of a block)
	 * and ensure that the blockstack finishes up in a sensible state (by
	 * popping any blocks we're jumping out of).  We look at all the
	 * blockstack operations between the current position and the new
	 * one, and keep track of how many blocks we drop out of on the way.
	 * By also keeping track of the lowest blockstack position we see, we
	 * can tell whether the jump goes into any blocks without coming out
	 * again - in that case we raise an exception below. */
	delta_iblock = 0;
	for (addr = min_addr; addr < max_addr; addr++) {
		unsigned char op = code[addr];
		switch (op) {
		case SETUP_LOOP:
		case SETUP_EXCEPT:
		case SETUP_FINALLY:
			delta_iblock++;
			break;

		case POP_BLOCK:
			delta_iblock--;
			break;
		}

		min_delta_iblock = MIN(min_delta_iblock, delta_iblock);

		if (op >= HAVE_ARGUMENT) {
			addr += 2;
		}
	}

	/* Derive the absolute iblock values from the deltas. */
	min_iblock = f->f_iblock + min_delta_iblock;
	if (new_lasti > f->f_lasti) {
		/* Forwards jump. */
		new_iblock = f->f_iblock + delta_iblock;
	}
	else {
		/* Backwards jump. */
		new_iblock = f->f_iblock - delta_iblock;
	}

	/* Are we jumping into a block? */
	if (new_iblock > min_iblock) {
		PyErr_SetString(PyExc_ValueError,
				"can't jump into the middle of a block");
		return -1;
	}

	/* Pop any blocks that we're jumping out of. */
	while (f->f_iblock > new_iblock) {
		PyTryBlock *b = &f->f_blockstack[--f->f_iblock];
		while ((f->f_stacktop - f->f_valuestack) > b->b_level) {
			PyObject *v = (*--f->f_stacktop);
			Py_DECREF(v);
		}
	}

	/* Finally set the new f_lineno and f_lasti and return OK. */
	f->f_lineno = new_lineno;
	f->f_lasti = new_lasti;
	return 0;
}

static PyObject *
frame_gettrace(PyFrameObject *f, void *closure)
{
	PyObject* trace = f->f_trace;

	if (trace == NULL)
		trace = Py_None;

	Py_INCREF(trace);

	return trace;
}

static int
frame_settrace(PyFrameObject *f, PyObject* v, void *closure)
{
	/* We rely on f_lineno being accurate when f_trace is set. */

	PyObject* old_value = f->f_trace;

	Py_XINCREF(v);
	f->f_trace = v;
	
	if (v != NULL)
		f->f_lineno = PyCode_Addr2Line(f->f_code, f->f_lasti);

	Py_XDECREF(old_value);

	return 0;
}

static PyGetSetDef frame_getsetlist[] = {
	{"f_locals",	(getter)frame_getlocals, NULL, NULL},
	{"f_lineno",	(getter)frame_getlineno,
			(setter)frame_setlineno, NULL},
	{"f_trace",	(getter)frame_gettrace, (setter)frame_settrace, NULL},
	{0}
};

/* Stack frames are allocated and deallocated at a considerable rate.
   In an attempt to improve the speed of function calls, we maintain a
   separate free list of stack frames (just like integers are
   allocated in a special way -- see intobject.c).  When a stack frame
   is on the free list, only the following members have a meaning:
	ob_type		== &Frametype
	f_back		next item on free list, or NULL
	f_nlocals	number of locals
	f_stacksize	size of value stack
        ob_size         size of localsplus
   Note that the value and block stacks are preserved -- this can save
   another malloc() call or two (and two free() calls as well!).
   Also note that, unlike for integers, each frame object is a
   malloc'ed object in its own right -- it is only the actual calls to
   malloc() that we are trying to save here, not the administration.
   After all, while a typical program may make millions of calls, a
   call depth of more than 20 or 30 is probably already exceptional
   unless the program contains run-away recursion.  I hope.

   Later, MAXFREELIST was added to bound the # of frames saved on
   free_list.  Else programs creating lots of cyclic trash involving
   frames could provoke free_list into growing without bound.
*/

static PyFrameObject *free_list = NULL;
static int numfree = 0;		/* number of frames currently in free_list */
#define MAXFREELIST 200		/* max value for numfree */

static void
frame_dealloc(PyFrameObject *f)
{
	int i, slots;
	PyObject **fastlocals;
	PyObject **p;

 	PyObject_GC_UnTrack(f);
	Py_TRASHCAN_SAFE_BEGIN(f)
	/* Kill all local variables */
	slots = f->f_nlocals + f->f_ncells + f->f_nfreevars;
	fastlocals = f->f_localsplus;
	for (i = slots; --i >= 0; ++fastlocals) {
		Py_XDECREF(*fastlocals);
	}

	/* Free stack */
	if (f->f_stacktop != NULL) {
		for (p = f->f_valuestack; p < f->f_stacktop; p++)
			Py_XDECREF(*p);
	}
	
	Py_XDECREF(f->f_back);
	Py_DECREF(f->f_code);
	Py_DECREF(f->f_builtins);
	Py_DECREF(f->f_globals);
	Py_XDECREF(f->f_locals);
	Py_XDECREF(f->f_trace);
	Py_XDECREF(f->f_exc_type);
	Py_XDECREF(f->f_exc_value);
	Py_XDECREF(f->f_exc_traceback);
	if (numfree < MAXFREELIST) {
		++numfree;
		f->f_back = free_list;
		free_list = f;
	}
	else
		PyObject_GC_Del(f);
	Py_TRASHCAN_SAFE_END(f)
}

static int
frame_traverse(PyFrameObject *f, visitproc visit, void *arg)
{
	PyObject **fastlocals, **p;
	int i, err, slots;
#define VISIT(o) if (o) {if ((err = visit((PyObject *)(o), arg))) return err;}

	VISIT(f->f_back);
	VISIT(f->f_code);
	VISIT(f->f_builtins);
	VISIT(f->f_globals);
	VISIT(f->f_locals);
	VISIT(f->f_trace);
	VISIT(f->f_exc_type);
	VISIT(f->f_exc_value);
	VISIT(f->f_exc_traceback);

	/* locals */
	slots = f->f_nlocals + f->f_ncells + f->f_nfreevars;
	fastlocals = f->f_localsplus;
	for (i = slots; --i >= 0; ++fastlocals) {
		VISIT(*fastlocals);
	}

	/* stack */
	if (f->f_stacktop != NULL) {
		for (p = f->f_valuestack; p < f->f_stacktop; p++)
			VISIT(*p);
	}
	return 0;
}

static void
frame_clear(PyFrameObject *f)
{
	PyObject **fastlocals, **p;
	int i, slots;

	Py_XDECREF(f->f_exc_type);
	f->f_exc_type = NULL;

	Py_XDECREF(f->f_exc_value);
	f->f_exc_value = NULL;

	Py_XDECREF(f->f_exc_traceback);
	f->f_exc_traceback = NULL;

	Py_XDECREF(f->f_trace);
	f->f_trace = NULL;

	/* locals */
	slots = f->f_nlocals + f->f_ncells + f->f_nfreevars;
	fastlocals = f->f_localsplus;
	for (i = slots; --i >= 0; ++fastlocals) {
		if (*fastlocals != NULL) {
			Py_XDECREF(*fastlocals);
			*fastlocals = NULL;
		}
	}

	/* stack */
	if (f->f_stacktop != NULL) {
		for (p = f->f_valuestack; p < f->f_stacktop; p++) {
			Py_XDECREF(*p);
			*p = NULL;
		}
	}
}


PyTypeObject PyFrame_Type = {
	PyObject_HEAD_INIT(&PyType_Type)
	0,
	"frame",
	sizeof(PyFrameObject),
	sizeof(PyObject *),
	(destructor)frame_dealloc, 		/* tp_dealloc */
	0,					/* tp_print */
	0, 					/* tp_getattr */
	0,			 		/* tp_setattr */
	0,					/* tp_compare */
	0,					/* tp_repr */
	0,					/* tp_as_number */
	0,					/* tp_as_sequence */
	0,					/* tp_as_mapping */
	0,					/* tp_hash */
	0,					/* tp_call */
	0,					/* tp_str */
	PyObject_GenericGetAttr,		/* tp_getattro */
	PyObject_GenericSetAttr,		/* tp_setattro */
	0,					/* tp_as_buffer */
	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,/* tp_flags */
	0,             				/* tp_doc */
 	(traverseproc)frame_traverse,		/* tp_traverse */
	(inquiry)frame_clear,			/* tp_clear */
	0,					/* tp_richcompare */
	0,					/* tp_weaklistoffset */
	0,					/* tp_iter */
	0,					/* tp_iternext */
	0,					/* tp_methods */
	frame_memberlist,			/* tp_members */
	frame_getsetlist,			/* tp_getset */
	0,					/* tp_base */
	0,					/* tp_dict */
};

static PyObject *builtin_object;

int _PyFrame_Init()
{
	builtin_object = PyString_InternFromString("__builtins__");
	return (builtin_object != NULL);
}

PyFrameObject *
PyFrame_New(PyThreadState *tstate, PyCodeObject *code, PyObject *globals, 
	    PyObject *locals)
{
	PyFrameObject *back = tstate->frame;
	PyFrameObject *f;
	PyObject *builtins;
	int extras, ncells, nfrees, i;

#ifdef Py_DEBUG
	if (code == NULL || globals == NULL || !PyDict_Check(globals) ||
	    (locals != NULL && !PyMapping_Check(locals))) {
		PyErr_BadInternalCall();
		return NULL;
	}
#endif
	ncells = PyTuple_GET_SIZE(code->co_cellvars);
	nfrees = PyTuple_GET_SIZE(code->co_freevars);
	extras = code->co_stacksize + code->co_nlocals + ncells + nfrees;
	if (back == NULL || back->f_globals != globals) {
		builtins = PyDict_GetItem(globals, builtin_object);
		if (builtins) {
			if (PyModule_Check(builtins)) {
				builtins = PyModule_GetDict(builtins);
				assert(!builtins || PyDict_Check(builtins));
			}
			else if (!PyDict_Check(builtins))
				builtins = NULL;
		}
		if (builtins == NULL) {
			/* No builtins!  Make up a minimal one 
			   Give them 'None', at least. */
			builtins = PyDict_New();
			if (builtins == NULL || 
			    PyDict_SetItemString(
				    builtins, "None", Py_None) < 0)
				return NULL;
		}
		else
			Py_INCREF(builtins);

	}
	else {
		/* If we share the globals, we share the builtins.
		   Save a lookup and a call. */
		builtins = back->f_builtins;
		assert(builtins != NULL && PyDict_Check(builtins));
		Py_INCREF(builtins);
	}
	if (free_list == NULL) {
		f = PyObject_GC_NewVar(PyFrameObject, &PyFrame_Type, extras);
		if (f == NULL) {
			Py_DECREF(builtins);
			return NULL;
		}
	}
	else {
		assert(numfree > 0);
		--numfree;
		f = free_list;
		free_list = free_list->f_back;
		if (f->ob_size < extras) {
			f = PyObject_GC_Resize(PyFrameObject, f, extras);
			if (f == NULL) {
				Py_DECREF(builtins);
				return NULL;
			}
		}
		_Py_NewReference((PyObject *)f);
	}
	f->f_builtins = builtins;
	Py_XINCREF(back);
	f->f_back = back;
	Py_INCREF(code);
	f->f_code = code;
	Py_INCREF(globals);
	f->f_globals = globals;
	/* Most functions have CO_NEWLOCALS and CO_OPTIMIZED set. */
	if ((code->co_flags & (CO_NEWLOCALS | CO_OPTIMIZED)) == 
		(CO_NEWLOCALS | CO_OPTIMIZED))
		locals = NULL; /* PyFrame_FastToLocals() will set. */
	else if (code->co_flags & CO_NEWLOCALS) {
		locals = PyDict_New();
		if (locals == NULL) {
			Py_DECREF(f);
			return NULL;
		}
	}
	else {
		if (locals == NULL)
			locals = globals;
		Py_INCREF(locals);
	}
	f->f_locals = locals;
	f->f_trace = NULL;
	f->f_exc_type = f->f_exc_value = f->f_exc_traceback = NULL;
	f->f_tstate = tstate;

	f->f_lasti = -1;
	f->f_lineno = code->co_firstlineno;
	f->f_restricted = (builtins != tstate->interp->builtins);
	f->f_iblock = 0;
	f->f_nlocals = code->co_nlocals;
	f->f_stacksize = code->co_stacksize;
	f->f_ncells = ncells;
	f->f_nfreevars = nfrees;

	extras = f->f_nlocals + ncells + nfrees;
	/* Tim said it's ok to replace memset */
	for (i=0; i<extras; i++)
		f->f_localsplus[i] = NULL;

	f->f_valuestack = f->f_localsplus + extras;
	f->f_stacktop = f->f_valuestack;
	_PyObject_GC_TRACK(f);
	return f;
}

/* Block management */

void
PyFrame_BlockSetup(PyFrameObject *f, int type, int handler, int level)
{
	PyTryBlock *b;
	if (f->f_iblock >= CO_MAXBLOCKS)
		Py_FatalError("XXX block stack overflow");
	b = &f->f_blockstack[f->f_iblock++];
	b->b_type = type;
	b->b_level = level;
	b->b_handler = handler;
}

PyTryBlock *
PyFrame_BlockPop(PyFrameObject *f)
{
	PyTryBlock *b;
	if (f->f_iblock <= 0)
		Py_FatalError("XXX block stack underflow");
	b = &f->f_blockstack[--f->f_iblock];
	return b;
}

/* Convert between "fast" version of locals and dictionary version */

static void
map_to_dict(PyObject *map, int nmap, PyObject *dict, PyObject **values,
	    int deref)
{
	int j;
	for (j = nmap; --j >= 0; ) {
		PyObject *key = PyTuple_GET_ITEM(map, j);
		PyObject *value = values[j];
		if (deref)
			value = PyCell_GET(value);
		if (value == NULL) {
			if (PyObject_DelItem(dict, key) != 0)
				PyErr_Clear();
		}
		else {
			if (PyObject_SetItem(dict, key, value) != 0)
				PyErr_Clear();
		}
	}
}

static void
dict_to_map(PyObject *map, int nmap, PyObject *dict, PyObject **values,
	    int deref, int clear)
{
	int j;
	for (j = nmap; --j >= 0; ) {
		PyObject *key = PyTuple_GET_ITEM(map, j);
		PyObject *value = PyObject_GetItem(dict, key);
		if (value == NULL)
			PyErr_Clear();
		if (deref) {
			if (value || clear) {
				if (PyCell_GET(values[j]) != value) {
					if (PyCell_Set(values[j], value) < 0)
						PyErr_Clear();
				}
			}
		} else if (value != NULL || clear) {
			if (values[j] != value) {
				Py_XINCREF(value);
				Py_XDECREF(values[j]);
				values[j] = value;
			}
		}
		Py_XDECREF(value);
	}
}

void
PyFrame_FastToLocals(PyFrameObject *f)
{
	/* Merge fast locals into f->f_locals */
	PyObject *locals, *map;
	PyObject **fast;
	PyObject *error_type, *error_value, *error_traceback;
	int j;
	if (f == NULL)
		return;
	locals = f->f_locals;
	if (locals == NULL) {
		locals = f->f_locals = PyDict_New();
		if (locals == NULL) {
			PyErr_Clear(); /* Can't report it :-( */
			return;
		}
	}
	map = f->f_code->co_varnames;
	if (!PyTuple_Check(map))
		return;
	PyErr_Fetch(&error_type, &error_value, &error_traceback);
	fast = f->f_localsplus;
	j = PyTuple_Size(map);
	if (j > f->f_nlocals)
		j = f->f_nlocals;
	if (f->f_nlocals)
		map_to_dict(map, j, locals, fast, 0);
	if (f->f_ncells || f->f_nfreevars) {
		if (!(PyTuple_Check(f->f_code->co_cellvars)
		      && PyTuple_Check(f->f_code->co_freevars))) {
			return;
		}
		map_to_dict(f->f_code->co_cellvars, 
			    PyTuple_GET_SIZE(f->f_code->co_cellvars),
			    locals, fast + f->f_nlocals, 1);
		map_to_dict(f->f_code->co_freevars, 
			    PyTuple_GET_SIZE(f->f_code->co_freevars),
			    locals, fast + f->f_nlocals + f->f_ncells, 1);
	}
	PyErr_Restore(error_type, error_value, error_traceback);
}

void
PyFrame_LocalsToFast(PyFrameObject *f, int clear)
{
	/* Merge f->f_locals into fast locals */
	PyObject *locals, *map;
	PyObject **fast;
	PyObject *error_type, *error_value, *error_traceback;
	int j;
	if (f == NULL)
		return;
	locals = f->f_locals;
	map = f->f_code->co_varnames;
	if (locals == NULL)
		return;
	if (!PyTuple_Check(map))
		return;
	PyErr_Fetch(&error_type, &error_value, &error_traceback);
	fast = f->f_localsplus;
	j = PyTuple_Size(map);
	if (j > f->f_nlocals)
		j = f->f_nlocals;
	if (f->f_nlocals)
	    dict_to_map(f->f_code->co_varnames, j, locals, fast, 0, clear);
	if (f->f_ncells || f->f_nfreevars) {
		if (!(PyTuple_Check(f->f_code->co_cellvars)
		      && PyTuple_Check(f->f_code->co_freevars)))
			return;
		dict_to_map(f->f_code->co_cellvars, 
			    PyTuple_GET_SIZE(f->f_code->co_cellvars),
			    locals, fast + f->f_nlocals, 1, clear);
		dict_to_map(f->f_code->co_freevars, 
			    PyTuple_GET_SIZE(f->f_code->co_freevars),
			    locals, fast + f->f_nlocals + f->f_ncells, 1, 
			    clear);
	}
	PyErr_Restore(error_type, error_value, error_traceback);
}

/* Clear out the free list */

void
PyFrame_Fini(void)
{
	while (free_list != NULL) {
		PyFrameObject *f = free_list;
		free_list = free_list->f_back;
		PyObject_GC_Del(f);
		--numfree;
	}
	assert(numfree == 0);
	Py_XDECREF(builtin_object);
	builtin_object = NULL;
}
Tip: Filter by directory path e.g. /media app.js to search for public/media/app.js.
Tip: Use camelCasing e.g. ProjME to search for ProjectModifiedEvent.java.
Tip: Filter by extension type e.g. /repo .js to search for all .js files in the /repo directory.
Tip: Separate your search with spaces e.g. /ssh pom.xml to search for src/ssh/pom.xml.
Tip: Use ↑ and ↓ arrow keys to navigate and return to view the file.
Tip: You can also navigate files with Ctrl+j (next) and Ctrl+k (previous) and view the file with Ctrl+o.
Tip: You can also navigate files with Alt+j (next) and Alt+k (previous) and view the file with Alt+o.