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Copy pathduk_api_stack.c
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4459 lines (3687 loc) · 127 KB
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/*
* API calls related to general value stack manipulation: resizing the value
* stack, pushing and popping values, type checking and reading values,
* coercing values, etc.
*
* Also contains internal functions (such as duk_get_tval()), defined
* in duk_api_internal.h, with semantics similar to the public API.
*/
/* XXX: repetition of stack pre-checks -> helper or macro or inline */
/* XXX: shared api error strings, and perhaps even throw code for rare cases? */
#include "duk_internal.h"
/*
* Forward declarations
*/
DUK_LOCAL_DECL duk_idx_t duk__push_c_function_raw(duk_context *ctx, duk_c_function func, duk_idx_t nargs, duk_uint_t flags);
/*
* Global state for working around missing variadic macros
*/
#ifndef DUK_USE_VARIADIC_MACROS
DUK_EXTERNAL const char *duk_api_global_filename = NULL;
DUK_EXTERNAL duk_int_t duk_api_global_line = 0;
#endif
/*
* Helpers
*/
#if defined(DUK_USE_VALSTACK_UNSAFE)
/* Faster but value stack overruns are memory unsafe. */
#define DUK__CHECK_SPACE() do { \
DUK_ASSERT(!(thr->valstack_top >= thr->valstack_end)); \
} while (0)
#else
#define DUK__CHECK_SPACE() do { \
if (thr->valstack_top >= thr->valstack_end) { \
DUK_ERROR(thr, DUK_ERR_API_ERROR, DUK_STR_PUSH_BEYOND_ALLOC_STACK); \
} \
} while (0)
#endif
DUK_LOCAL duk_int_t duk__api_coerce_d2i(duk_context *ctx, duk_idx_t index, duk_bool_t require) {
duk_hthread *thr;
duk_tval *tv;
duk_small_int_t c;
duk_double_t d;
thr = (duk_hthread *) ctx;
tv = duk_get_tval(ctx, index);
if (tv == NULL) {
goto error_notnumber;
}
/*
* Special cases like NaN and +/- Infinity are handled explicitly
* because a plain C coercion from double to int handles these cases
* in undesirable ways. For instance, NaN may coerce to INT_MIN
* (not zero), and INT_MAX + 1 may coerce to INT_MIN (not INT_MAX).
*
* This double-to-int coercion differs from ToInteger() because it
* has a finite range (ToInteger() allows e.g. +/- Infinity). It
* also differs from ToInt32() because the INT_MIN/INT_MAX clamping
* depends on the size of the int type on the platform. In particular,
* on platforms with a 64-bit int type, the full range is allowed.
*/
#if defined(DUK_USE_FASTINT)
if (DUK_TVAL_IS_FASTINT(tv)) {
duk_int64_t t = DUK_TVAL_GET_FASTINT(tv);
#if (DUK_INT_MAX <= 0x7fffffffL)
/* Clamping only necessary for 32-bit ints. */
if (t < DUK_INT_MIN) {
t = DUK_INT_MIN;
} else if (t > DUK_INT_MAX) {
t = DUK_INT_MAX;
}
#endif
return (duk_int_t) t;
}
#endif
if (DUK_TVAL_IS_NUMBER(tv)) {
d = DUK_TVAL_GET_NUMBER(tv);
c = (duk_small_int_t) DUK_FPCLASSIFY(d);
if (c == DUK_FP_NAN) {
return 0;
} else if (d < (duk_double_t) DUK_INT_MIN) {
/* covers -Infinity */
return DUK_INT_MIN;
} else if (d > (duk_double_t) DUK_INT_MAX) {
/* covers +Infinity */
return DUK_INT_MAX;
} else {
/* coerce towards zero */
return (duk_int_t) d;
}
}
error_notnumber:
if (require) {
DUK_ERROR(thr, DUK_ERR_TYPE_ERROR, DUK_STR_NOT_NUMBER);
/* not reachable */
}
return 0;
}
DUK_LOCAL duk_uint_t duk__api_coerce_d2ui(duk_context *ctx, duk_idx_t index, duk_bool_t require) {
duk_hthread *thr;
duk_tval *tv;
duk_small_int_t c;
duk_double_t d;
/* Same as above but for unsigned int range. */
thr = (duk_hthread *) ctx;
tv = duk_get_tval(ctx, index);
if (tv == NULL) {
goto error_notnumber;
}
#if defined(DUK_USE_FASTINT)
if (DUK_TVAL_IS_FASTINT(tv)) {
duk_int64_t t = DUK_TVAL_GET_FASTINT(tv);
if (t < 0) {
t = 0;
}
#if (DUK_UINT_MAX <= 0xffffffffUL)
/* Clamping only necessary for 32-bit ints. */
else if (t > DUK_UINT_MAX) {
t = DUK_UINT_MAX;
}
#endif
return (duk_uint_t) t;
}
#endif
if (DUK_TVAL_IS_NUMBER(tv)) {
d = DUK_TVAL_GET_NUMBER(tv);
c = (duk_small_int_t) DUK_FPCLASSIFY(d);
if (c == DUK_FP_NAN) {
return 0;
} else if (d < 0.0) {
/* covers -Infinity */
return (duk_uint_t) 0;
} else if (d > (duk_double_t) DUK_UINT_MAX) {
/* covers +Infinity */
return (duk_uint_t) DUK_UINT_MAX;
} else {
/* coerce towards zero */
return (duk_uint_t) d;
}
}
error_notnumber:
if (require) {
DUK_ERROR(thr, DUK_ERR_TYPE_ERROR, DUK_STR_NOT_NUMBER);
/* not reachable */
}
return 0;
}
/*
* Stack index validation/normalization and getting a stack duk_tval ptr.
*
* These are called by many API entrypoints so the implementations must be
* fast and "inlined".
*
* There's some repetition because of this; keep the functions in sync.
*/
DUK_EXTERNAL duk_idx_t duk_normalize_index(duk_context *ctx, duk_idx_t index) {
duk_hthread *thr = (duk_hthread *) ctx;
duk_idx_t vs_size;
DUK_ASSERT_CTX_VALID(ctx);
DUK_ASSERT(DUK_INVALID_INDEX < 0);
/* Care must be taken to avoid pointer wrapping in the index
* validation. For instance, on a 32-bit platform with 8-byte
* duk_tval the index 0x20000000UL would wrap the memory space
* once.
*/
/* Assume value stack sizes (in elements) fits into duk_idx_t. */
vs_size = (duk_idx_t) (thr->valstack_top - thr->valstack_bottom);
DUK_ASSERT(vs_size >= 0);
if (index < 0) {
index = vs_size + index;
if (DUK_UNLIKELY(index < 0)) {
/* Also catches index == DUK_INVALID_INDEX: vs_size >= 0
* so that vs_size + DUK_INVALID_INDEX cannot underflow
* and will always be negative.
*/
return DUK_INVALID_INDEX;
}
} else {
/* since index non-negative */
DUK_ASSERT(index != DUK_INVALID_INDEX);
if (DUK_UNLIKELY(index >= vs_size)) {
return DUK_INVALID_INDEX;
}
}
DUK_ASSERT(index >= 0);
DUK_ASSERT(index < vs_size);
return index;
}
DUK_EXTERNAL duk_idx_t duk_require_normalize_index(duk_context *ctx, duk_idx_t index) {
duk_hthread *thr = (duk_hthread *) ctx;
duk_idx_t vs_size;
DUK_ASSERT_CTX_VALID(ctx);
DUK_ASSERT(DUK_INVALID_INDEX < 0);
vs_size = (duk_idx_t) (thr->valstack_top - thr->valstack_bottom);
DUK_ASSERT(vs_size >= 0);
if (index < 0) {
index = vs_size + index;
if (DUK_UNLIKELY(index < 0)) {
goto invalid_index;
}
} else {
DUK_ASSERT(index != DUK_INVALID_INDEX);
if (DUK_UNLIKELY(index >= vs_size)) {
goto invalid_index;
}
}
DUK_ASSERT(index >= 0);
DUK_ASSERT(index < vs_size);
return index;
invalid_index:
DUK_ERROR(thr, DUK_ERR_API_ERROR, DUK_STR_INVALID_INDEX);
return 0; /* unreachable */
}
DUK_INTERNAL duk_tval *duk_get_tval(duk_context *ctx, duk_idx_t index) {
duk_hthread *thr = (duk_hthread *) ctx;
duk_idx_t vs_size;
DUK_ASSERT_CTX_VALID(ctx);
DUK_ASSERT(DUK_INVALID_INDEX < 0);
vs_size = (duk_idx_t) (thr->valstack_top - thr->valstack_bottom);
DUK_ASSERT(vs_size >= 0);
if (index < 0) {
index = vs_size + index;
if (DUK_UNLIKELY(index < 0)) {
return NULL;
}
} else {
DUK_ASSERT(index != DUK_INVALID_INDEX);
if (DUK_UNLIKELY(index >= vs_size)) {
return NULL;
}
}
DUK_ASSERT(index >= 0);
DUK_ASSERT(index < vs_size);
return thr->valstack_bottom + index;
}
DUK_INTERNAL duk_tval *duk_require_tval(duk_context *ctx, duk_idx_t index) {
duk_hthread *thr = (duk_hthread *) ctx;
duk_idx_t vs_size;
DUK_ASSERT_CTX_VALID(ctx);
DUK_ASSERT(DUK_INVALID_INDEX < 0);
vs_size = (duk_idx_t) (thr->valstack_top - thr->valstack_bottom);
DUK_ASSERT(vs_size >= 0);
if (index < 0) {
index = vs_size + index;
if (DUK_UNLIKELY(index < 0)) {
goto invalid_index;
}
} else {
DUK_ASSERT(index != DUK_INVALID_INDEX);
if (DUK_UNLIKELY(index >= vs_size)) {
goto invalid_index;
}
}
DUK_ASSERT(index >= 0);
DUK_ASSERT(index < vs_size);
return thr->valstack_bottom + index;
invalid_index:
DUK_ERROR(thr, DUK_ERR_API_ERROR, DUK_STR_INVALID_INDEX);
return NULL;
}
/* Non-critical. */
DUK_EXTERNAL duk_bool_t duk_is_valid_index(duk_context *ctx, duk_idx_t index) {
DUK_ASSERT_CTX_VALID(ctx);
DUK_ASSERT(DUK_INVALID_INDEX < 0);
return (duk_normalize_index(ctx, index) >= 0);
}
/* Non-critical. */
DUK_EXTERNAL void duk_require_valid_index(duk_context *ctx, duk_idx_t index) {
duk_hthread *thr = (duk_hthread *) ctx;
DUK_ASSERT_CTX_VALID(ctx);
DUK_ASSERT(DUK_INVALID_INDEX < 0);
if (duk_normalize_index(ctx, index) < 0) {
DUK_ERROR(thr, DUK_ERR_API_ERROR, DUK_STR_INVALID_INDEX);
}
}
/*
* Value stack top handling
*/
DUK_EXTERNAL duk_idx_t duk_get_top(duk_context *ctx) {
duk_hthread *thr = (duk_hthread *) ctx;
DUK_ASSERT_CTX_VALID(ctx);
return (duk_idx_t) (thr->valstack_top - thr->valstack_bottom);
}
/* set stack top within currently allocated range, but don't reallocate */
DUK_EXTERNAL void duk_set_top(duk_context *ctx, duk_idx_t index) {
duk_hthread *thr = (duk_hthread *) ctx;
duk_idx_t vs_size;
duk_idx_t vs_limit;
duk_idx_t count;
duk_tval tv_tmp;
duk_tval *tv;
DUK_ASSERT_CTX_VALID(ctx);
DUK_ASSERT(DUK_INVALID_INDEX < 0);
vs_size = (duk_idx_t) (thr->valstack_top - thr->valstack_bottom);
vs_limit = (duk_idx_t) (thr->valstack_end - thr->valstack_bottom);
if (index < 0) {
/* Negative indices are always within allocated stack but
* must not go below zero index.
*/
index = vs_size + index;
if (index < 0) {
/* Also catches index == DUK_INVALID_INDEX. */
goto invalid_index;
}
} else {
/* Positive index can be higher than valstack top but must
* not go above allocated stack (equality is OK).
*/
if (index > vs_limit) {
goto invalid_index;
}
}
DUK_ASSERT(index >= 0);
DUK_ASSERT(index <= vs_limit);
if (index >= vs_size) {
/* Stack size increases or stays the same. Fill the new
* entries (if any) with undefined. No pointer stability
* issues here so we can use a running pointer.
*/
tv = thr->valstack_top;
count = index - vs_size;
DUK_ASSERT(count >= 0);
while (count > 0) {
/* no need to decref previous or new value */
count--;
DUK_ASSERT(DUK_TVAL_IS_UNDEFINED_UNUSED(tv));
DUK_TVAL_SET_UNDEFINED_ACTUAL(tv);
tv++;
}
thr->valstack_top = tv;
} else {
/* Stack size decreases, DECREF entries which are above the
* new top. Each DECREF potentially invalidates valstack
* pointers, so don't hold on to pointers. The valstack top
* must also be updated on every loop in case a GC is triggered.
*/
/* XXX: Here it would be useful to have a DECREF macro which
* doesn't need a NULL check, and does refzero queueing without
* running the refzero algorithm. There would be no pointer
* instability in this case, and code could be inlined. After
* the loop, one call to refzero would be needed.
*/
count = vs_size - index;
DUK_ASSERT(count > 0);
while (count > 0) {
count--;
tv = --thr->valstack_top; /* tv -> value just before prev top value */
DUK_ASSERT(tv >= thr->valstack_bottom);
DUK_TVAL_SET_TVAL(&tv_tmp, tv);
DUK_TVAL_SET_UNDEFINED_UNUSED(tv);
DUK_TVAL_DECREF(thr, &tv_tmp); /* side effects */
/* XXX: fast primitive to set a bunch of values to UNDEFINED_UNUSED */
}
}
return;
invalid_index:
DUK_ERROR(thr, DUK_ERR_API_ERROR, DUK_STR_INVALID_INDEX);
}
DUK_EXTERNAL duk_idx_t duk_get_top_index(duk_context *ctx) {
duk_hthread *thr = (duk_hthread *) ctx;
duk_idx_t ret;
DUK_ASSERT_CTX_VALID(ctx);
ret = ((duk_idx_t) (thr->valstack_top - thr->valstack_bottom)) - 1;
if (DUK_UNLIKELY(ret < 0)) {
/* Return invalid index; if caller uses this without checking
* in another API call, the index won't map to a valid stack
* entry.
*/
return DUK_INVALID_INDEX;
}
return ret;
}
DUK_EXTERNAL duk_idx_t duk_require_top_index(duk_context *ctx) {
duk_hthread *thr = (duk_hthread *) ctx;
duk_idx_t ret;
DUK_ASSERT_CTX_VALID(ctx);
ret = ((duk_idx_t) (thr->valstack_top - thr->valstack_bottom)) - 1;
if (DUK_UNLIKELY(ret < 0)) {
DUK_ERROR(thr, DUK_ERR_API_ERROR, DUK_STR_INVALID_INDEX);
}
return ret;
}
/*
* Value stack resizing.
*
* This resizing happens above the current "top": the value stack can be
* grown or shrunk, but the "top" is not affected. The value stack cannot
* be resized to a size below the current "top".
*
* The low level reallocation primitive must carefully recompute all value
* stack pointers, and must also work if ALL pointers are NULL. The resize
* is quite tricky because the valstack realloc may cause a mark-and-sweep,
* which may run finalizers. Running finalizers may resize the valstack
* recursively (the same value stack we're working on). So, after realloc
* returns, we know that the valstack "top" should still be the same (there
* should not be live values above the "top"), but its underlying size and
* pointer may have changed.
*/
/* XXX: perhaps refactor this to allow caller to specify some parameters, or
* at least a 'compact' flag which skips any spare or round-up .. useful for
* emergency gc.
*/
DUK_LOCAL duk_bool_t duk__resize_valstack(duk_context *ctx, duk_size_t new_size) {
duk_hthread *thr = (duk_hthread *) ctx;
duk_ptrdiff_t old_bottom_offset;
duk_ptrdiff_t old_top_offset;
duk_ptrdiff_t old_end_offset_post;
#ifdef DUK_USE_DEBUG
duk_ptrdiff_t old_end_offset_pre;
duk_tval *old_valstack_pre;
duk_tval *old_valstack_post;
#endif
duk_tval *new_valstack;
duk_tval *p;
duk_size_t new_alloc_size;
DUK_ASSERT_CTX_VALID(ctx);
DUK_ASSERT(thr != NULL);
DUK_ASSERT(thr->valstack_bottom >= thr->valstack);
DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
DUK_ASSERT(thr->valstack_end >= thr->valstack_top);
DUK_ASSERT((duk_size_t) (thr->valstack_top - thr->valstack) <= new_size); /* can't resize below 'top' */
DUK_ASSERT(new_size <= thr->valstack_max); /* valstack limit caller has check, prevents wrapping */
DUK_ASSERT(new_size <= DUK_SIZE_MAX / sizeof(duk_tval)); /* specific assert for wrapping */
/* get pointer offsets for tweaking below */
old_bottom_offset = (((duk_uint8_t *) thr->valstack_bottom) - ((duk_uint8_t *) thr->valstack));
old_top_offset = (((duk_uint8_t *) thr->valstack_top) - ((duk_uint8_t *) thr->valstack));
#ifdef DUK_USE_DEBUG
old_end_offset_pre = (((duk_uint8_t *) thr->valstack_end) - ((duk_uint8_t *) thr->valstack)); /* not very useful, used for debugging */
old_valstack_pre = thr->valstack;
#endif
/* Allocate a new valstack.
*
* Note: cannot use a plain DUK_REALLOC() because a mark-and-sweep may
* invalidate the original thr->valstack base pointer inside the realloc
* process. See doc/memory-management.rst.
*/
new_alloc_size = sizeof(duk_tval) * new_size;
new_valstack = (duk_tval *) DUK_REALLOC_INDIRECT(thr->heap, duk_hthread_get_valstack_ptr, (void *) thr, new_alloc_size);
if (!new_valstack) {
/* Because new_size != 0, if condition doesn't need to be
* (new_valstack != NULL || new_size == 0).
*/
DUK_ASSERT(new_size != 0);
DUK_D(DUK_DPRINT("failed to resize valstack to %lu entries (%lu bytes)",
(unsigned long) new_size, (unsigned long) new_alloc_size));
return 0;
}
/* Note: the realloc may have triggered a mark-and-sweep which may
* have resized our valstack internally. However, the mark-and-sweep
* MUST NOT leave the stack bottom/top in a different state. Particular
* assumptions and facts:
*
* - The thr->valstack pointer may be different after realloc,
* and the offset between thr->valstack_end <-> thr->valstack
* may have changed.
* - The offset between thr->valstack_bottom <-> thr->valstack
* and thr->valstack_top <-> thr->valstack MUST NOT have changed,
* because mark-and-sweep must adhere to a strict stack policy.
* In other words, logical bottom and top MUST NOT have changed.
* - All values above the top are unreachable but are initialized
* to UNDEFINED_UNUSED, up to the post-realloc valstack_end.
* - 'old_end_offset' must be computed after realloc to be correct.
*/
DUK_ASSERT((((duk_uint8_t *) thr->valstack_bottom) - ((duk_uint8_t *) thr->valstack)) == old_bottom_offset);
DUK_ASSERT((((duk_uint8_t *) thr->valstack_top) - ((duk_uint8_t *) thr->valstack)) == old_top_offset);
/* success, fixup pointers */
old_end_offset_post = (((duk_uint8_t *) thr->valstack_end) - ((duk_uint8_t *) thr->valstack)); /* must be computed after realloc */
#ifdef DUK_USE_DEBUG
old_valstack_post = thr->valstack;
#endif
thr->valstack = new_valstack;
thr->valstack_end = new_valstack + new_size;
thr->valstack_bottom = (duk_tval *) (void *) ((duk_uint8_t *) new_valstack + old_bottom_offset);
thr->valstack_top = (duk_tval *) (void *) ((duk_uint8_t *) new_valstack + old_top_offset);
DUK_ASSERT(thr->valstack_bottom >= thr->valstack);
DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
DUK_ASSERT(thr->valstack_end >= thr->valstack_top);
/* useful for debugging */
#ifdef DUK_USE_DEBUG
if (old_end_offset_pre != old_end_offset_post) {
DUK_D(DUK_DPRINT("valstack was resized during valstack_resize(), probably by mark-and-sweep; "
"end offset changed: %lu -> %lu",
(unsigned long) old_end_offset_pre,
(unsigned long) old_end_offset_post));
}
if (old_valstack_pre != old_valstack_post) {
DUK_D(DUK_DPRINT("valstack pointer changed during valstack_resize(), probably by mark-and-sweep: %p -> %p",
(void *) old_valstack_pre,
(void *) old_valstack_post));
}
#endif
DUK_DD(DUK_DDPRINT("resized valstack to %lu elements (%lu bytes), bottom=%ld, top=%ld, "
"new pointers: start=%p end=%p bottom=%p top=%p",
(unsigned long) new_size, (unsigned long) new_alloc_size,
(long) (thr->valstack_bottom - thr->valstack),
(long) (thr->valstack_top - thr->valstack),
(void *) thr->valstack, (void *) thr->valstack_end,
(void *) thr->valstack_bottom, (void *) thr->valstack_top));
/* init newly allocated slots (only) */
p = (duk_tval *) (void *) ((duk_uint8_t *) thr->valstack + old_end_offset_post);
while (p < thr->valstack_end) {
/* never executed if new size is smaller */
DUK_TVAL_SET_UNDEFINED_UNUSED(p);
p++;
}
/* assertion check: we maintain elements above top in known state */
#ifdef DUK_USE_ASSERTIONS
p = thr->valstack_top;
while (p < thr->valstack_end) {
/* everything above old valstack top should be preinitialized now */
DUK_ASSERT(DUK_TVAL_IS_UNDEFINED_UNUSED(p));
p++;
}
#endif
return 1;
}
DUK_INTERNAL
duk_bool_t duk_valstack_resize_raw(duk_context *ctx,
duk_size_t min_new_size,
duk_small_uint_t flags) {
duk_hthread *thr = (duk_hthread *) ctx;
duk_size_t old_size;
duk_size_t new_size;
duk_bool_t is_shrink = 0;
duk_small_uint_t shrink_flag = (flags & DUK_VSRESIZE_FLAG_SHRINK);
duk_small_uint_t compact_flag = (flags & DUK_VSRESIZE_FLAG_COMPACT);
duk_small_uint_t throw_flag = (flags & DUK_VSRESIZE_FLAG_THROW);
DUK_DDD(DUK_DDDPRINT("check valstack resize: min_new_size=%lu, curr_size=%ld, curr_top=%ld, "
"curr_bottom=%ld, shrink=%d, compact=%d, throw=%d",
(unsigned long) min_new_size,
(long) (thr->valstack_end - thr->valstack),
(long) (thr->valstack_top - thr->valstack),
(long) (thr->valstack_bottom - thr->valstack),
(int) shrink_flag, (int) compact_flag, (int) throw_flag));
DUK_ASSERT_CTX_VALID(ctx);
DUK_ASSERT(thr != NULL);
DUK_ASSERT(thr->valstack_bottom >= thr->valstack);
DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
DUK_ASSERT(thr->valstack_end >= thr->valstack_top);
old_size = (duk_size_t) (thr->valstack_end - thr->valstack);
if (min_new_size <= old_size) {
is_shrink = 1;
if (!shrink_flag ||
old_size - min_new_size < DUK_VALSTACK_SHRINK_THRESHOLD) {
DUK_DDD(DUK_DDDPRINT("no need to grow or shrink valstack"));
return 1;
}
}
new_size = min_new_size;
if (!compact_flag) {
if (is_shrink) {
/* shrink case; leave some spare */
new_size += DUK_VALSTACK_SHRINK_SPARE;
}
/* round up roughly to next 'grow step' */
new_size = (new_size / DUK_VALSTACK_GROW_STEP + 1) * DUK_VALSTACK_GROW_STEP;
}
DUK_DD(DUK_DDPRINT("want to %s valstack: %lu -> %lu elements (min_new_size %lu)",
(const char *) (new_size > old_size ? "grow" : "shrink"),
(unsigned long) old_size, (unsigned long) new_size,
(unsigned long) min_new_size));
if (new_size > thr->valstack_max) {
/* Note: may be triggered even if minimal new_size would not reach the limit,
* plan limit accordingly (taking DUK_VALSTACK_GROW_STEP into account).
*/
if (throw_flag) {
DUK_ERROR(thr, DUK_ERR_RANGE_ERROR, DUK_STR_VALSTACK_LIMIT);
} else {
return 0;
}
}
/*
* When resizing the valstack, a mark-and-sweep may be triggered for
* the allocation of the new valstack. If the mark-and-sweep needs
* to use our thread for something, it may cause *the same valstack*
* to be resized recursively. This happens e.g. when mark-and-sweep
* finalizers are called. This is taken into account carefully in
* duk__resize_valstack().
*
* 'new_size' is known to be <= valstack_max, which ensures that
* size_t and pointer arithmetic won't wrap in duk__resize_valstack().
*/
if (!duk__resize_valstack(ctx, new_size)) {
if (is_shrink) {
DUK_DD(DUK_DDPRINT("valstack resize failed, but is a shrink, ignore"));
return 1;
}
DUK_DD(DUK_DDPRINT("valstack resize failed"));
if (throw_flag) {
DUK_ERROR(thr, DUK_ERR_ALLOC_ERROR, DUK_STR_FAILED_TO_EXTEND_VALSTACK);
} else {
return 0;
}
}
DUK_DDD(DUK_DDDPRINT("valstack resize successful"));
return 1;
}
DUK_EXTERNAL duk_bool_t duk_check_stack(duk_context *ctx, duk_idx_t extra) {
duk_hthread *thr = (duk_hthread *) ctx;
duk_size_t min_new_size;
DUK_ASSERT_CTX_VALID(ctx);
DUK_ASSERT(thr != NULL);
if (DUK_UNLIKELY(extra < 0)) {
/* Clamping to zero makes the API more robust to calling code
* calculation errors.
*/
extra = 0;
}
min_new_size = (thr->valstack_top - thr->valstack) + extra + DUK_VALSTACK_INTERNAL_EXTRA;
return duk_valstack_resize_raw(ctx,
min_new_size, /* min_new_size */
0 /* no shrink */ | /* flags */
0 /* no compact */ |
0 /* no throw */);
}
DUK_EXTERNAL void duk_require_stack(duk_context *ctx, duk_idx_t extra) {
duk_hthread *thr = (duk_hthread *) ctx;
duk_size_t min_new_size;
DUK_ASSERT_CTX_VALID(ctx);
DUK_ASSERT(thr != NULL);
if (DUK_UNLIKELY(extra < 0)) {
/* Clamping to zero makes the API more robust to calling code
* calculation errors.
*/
extra = 0;
}
min_new_size = (thr->valstack_top - thr->valstack) + extra + DUK_VALSTACK_INTERNAL_EXTRA;
(void) duk_valstack_resize_raw(ctx,
min_new_size, /* min_new_size */
0 /* no shrink */ | /* flags */
0 /* no compact */ |
DUK_VSRESIZE_FLAG_THROW);
}
DUK_EXTERNAL duk_bool_t duk_check_stack_top(duk_context *ctx, duk_idx_t top) {
duk_size_t min_new_size;
DUK_ASSERT_CTX_VALID(ctx);
if (DUK_UNLIKELY(top < 0)) {
/* Clamping to zero makes the API more robust to calling code
* calculation errors.
*/
top = 0;
}
min_new_size = top + DUK_VALSTACK_INTERNAL_EXTRA;
return duk_valstack_resize_raw(ctx,
min_new_size, /* min_new_size */
0 /* no shrink */ | /* flags */
0 /* no compact */ |
0 /* no throw */);
}
DUK_EXTERNAL void duk_require_stack_top(duk_context *ctx, duk_idx_t top) {
duk_size_t min_new_size;
DUK_ASSERT_CTX_VALID(ctx);
if (DUK_UNLIKELY(top < 0)) {
/* Clamping to zero makes the API more robust to calling code
* calculation errors.
*/
top = 0;
}
min_new_size = top + DUK_VALSTACK_INTERNAL_EXTRA;
(void) duk_valstack_resize_raw(ctx,
min_new_size, /* min_new_size */
0 /* no shrink */ | /* flags */
0 /* no compact */ |
DUK_VSRESIZE_FLAG_THROW);
}
/*
* Basic stack manipulation: swap, dup, insert, replace, etc
*/
DUK_EXTERNAL void duk_swap(duk_context *ctx, duk_idx_t index1, duk_idx_t index2) {
duk_tval *tv1;
duk_tval *tv2;
duk_tval tv_tmp;
DUK_ASSERT_CTX_VALID(ctx);
tv1 = duk_require_tval(ctx, index1);
DUK_ASSERT(tv1 != NULL);
tv2 = duk_require_tval(ctx, index2);
DUK_ASSERT(tv2 != NULL);
/* If tv1==tv2 this is a NOP, no check is needed */
DUK_TVAL_SET_TVAL(&tv_tmp, tv1);
DUK_TVAL_SET_TVAL(tv1, tv2);
DUK_TVAL_SET_TVAL(tv2, &tv_tmp);
}
DUK_EXTERNAL void duk_swap_top(duk_context *ctx, duk_idx_t index) {
DUK_ASSERT_CTX_VALID(ctx);
duk_swap(ctx, index, -1);
}
DUK_EXTERNAL void duk_dup(duk_context *ctx, duk_idx_t from_index) {
duk_hthread *thr;
duk_tval *tv_from;
duk_tval *tv_to;
DUK_ASSERT_CTX_VALID(ctx);
thr = (duk_hthread *) ctx;
DUK__CHECK_SPACE();
tv_from = duk_require_tval(ctx, from_index);
tv_to = thr->valstack_top++;
DUK_ASSERT(tv_from != NULL);
DUK_ASSERT(tv_to != NULL);
DUK_TVAL_SET_TVAL(tv_to, tv_from);
DUK_TVAL_INCREF(thr, tv_to); /* no side effects */
}
DUK_EXTERNAL void duk_dup_top(duk_context *ctx) {
duk_hthread *thr;
duk_tval *tv_from;
duk_tval *tv_to;
DUK_ASSERT_CTX_VALID(ctx);
thr = (duk_hthread *) ctx;
DUK__CHECK_SPACE();
if (thr->valstack_top - thr->valstack_bottom <= 0) {
DUK_ERROR(thr, DUK_ERR_API_ERROR, DUK_STR_INVALID_INDEX);
}
tv_from = thr->valstack_top - 1;
tv_to = thr->valstack_top++;
DUK_ASSERT(tv_from != NULL);
DUK_ASSERT(tv_to != NULL);
DUK_TVAL_SET_TVAL(tv_to, tv_from);
DUK_TVAL_INCREF(thr, tv_to); /* no side effects */
}
DUK_EXTERNAL void duk_insert(duk_context *ctx, duk_idx_t to_index) {
duk_tval *p;
duk_tval *q;
duk_tval tv_tmp;
duk_size_t nbytes;
DUK_ASSERT_CTX_VALID(ctx);
p = duk_require_tval(ctx, to_index);
DUK_ASSERT(p != NULL);
q = duk_require_tval(ctx, -1);
DUK_ASSERT(q != NULL);
DUK_ASSERT(q >= p);
/* nbytes
* <--------->
* [ ... | p | x | x | q ]
* => [ ... | q | p | x | x ]
*/
nbytes = (duk_size_t) (((duk_uint8_t *) q) - ((duk_uint8_t *) p)); /* Note: 'q' is top-1 */
DUK_DDD(DUK_DDDPRINT("duk_insert: to_index=%ld, p=%p, q=%p, nbytes=%lu",
(long) to_index, (void *) p, (void *) q, (unsigned long) nbytes));
/* No net refcount changes. */
if (nbytes > 0) {
DUK_TVAL_SET_TVAL(&tv_tmp, q);
DUK_ASSERT(nbytes > 0);
DUK_MEMMOVE((void *) (p + 1), (void *) p, nbytes);
DUK_TVAL_SET_TVAL(p, &tv_tmp);
} else {
/* nop: insert top to top */
DUK_ASSERT(nbytes == 0);
DUK_ASSERT(p == q);
}
}
DUK_EXTERNAL void duk_replace(duk_context *ctx, duk_idx_t to_index) {
duk_hthread *thr = (duk_hthread *) ctx;
duk_tval *tv1;
duk_tval *tv2;
duk_tval tv_tmp;
DUK_ASSERT_CTX_VALID(ctx);
tv1 = duk_require_tval(ctx, -1);
DUK_ASSERT(tv1 != NULL);
tv2 = duk_require_tval(ctx, to_index);
DUK_ASSERT(tv2 != NULL);
/* For tv1 == tv2, both pointing to stack top, the end result
* is same as duk_pop(ctx).
*/
DUK_TVAL_SET_TVAL(&tv_tmp, tv2);
DUK_TVAL_SET_TVAL(tv2, tv1);
DUK_TVAL_SET_UNDEFINED_UNUSED(tv1);
thr->valstack_top--;
DUK_TVAL_DECREF(thr, &tv_tmp); /* side effects */
}
DUK_EXTERNAL void duk_copy(duk_context *ctx, duk_idx_t from_index, duk_idx_t to_index) {
duk_hthread *thr = (duk_hthread *) ctx;
duk_tval *tv1;
duk_tval *tv2;
duk_tval tv_tmp;
DUK_ASSERT_CTX_VALID(ctx);
DUK_UNREF(thr); /* w/o refcounting */
tv1 = duk_require_tval(ctx, from_index);
DUK_ASSERT(tv1 != NULL);
tv2 = duk_require_tval(ctx, to_index);
DUK_ASSERT(tv2 != NULL);
/* For tv1 == tv2, this is a no-op (no explicit check needed). */
DUK_TVAL_SET_TVAL(&tv_tmp, tv2);
DUK_TVAL_SET_TVAL(tv2, tv1);
DUK_TVAL_INCREF(thr, tv2); /* no side effects */
DUK_TVAL_DECREF(thr, &tv_tmp); /* side effects */
}
DUK_EXTERNAL void duk_remove(duk_context *ctx, duk_idx_t index) {
duk_hthread *thr = (duk_hthread *) ctx;
duk_tval *p;
duk_tval *q;
#ifdef DUK_USE_REFERENCE_COUNTING
duk_tval tv_tmp;
#endif
duk_size_t nbytes;
DUK_ASSERT_CTX_VALID(ctx);
p = duk_require_tval(ctx, index);
DUK_ASSERT(p != NULL);
q = duk_require_tval(ctx, -1);
DUK_ASSERT(q != NULL);
DUK_ASSERT(q >= p);
/* nbytes zero size case
* <--------->
* [ ... | p | x | x | q ] [ ... | p==q ]
* => [ ... | x | x | q ] [ ... ]
*/
#ifdef DUK_USE_REFERENCE_COUNTING
/* use a temp: decref only when valstack reachable values are correct */
DUK_TVAL_SET_TVAL(&tv_tmp, p);
#endif
nbytes = (duk_size_t) (((duk_uint8_t *) q) - ((duk_uint8_t *) p)); /* Note: 'q' is top-1 */
DUK_MEMMOVE(p, p + 1, nbytes); /* zero size not an issue: pointers are valid */
DUK_TVAL_SET_UNDEFINED_UNUSED(q);
thr->valstack_top--;
#ifdef DUK_USE_REFERENCE_COUNTING
DUK_TVAL_DECREF(thr, &tv_tmp); /* side effects */
#endif
}
/*
* Stack slice primitives
*/
DUK_EXTERNAL void duk_xcopymove_raw(duk_context *to_ctx, duk_context *from_ctx, duk_idx_t count, duk_bool_t is_copy) {
duk_hthread *to_thr = (duk_hthread *) to_ctx;
duk_hthread *from_thr = (duk_hthread *) from_ctx;
void *src;
duk_size_t nbytes;
duk_tval *p;
duk_tval *q;
/* XXX: several pointer comparison issues here */
DUK_ASSERT_CTX_VALID(to_ctx);
DUK_ASSERT_CTX_VALID(from_ctx);
DUK_ASSERT(to_ctx != NULL);
DUK_ASSERT(from_ctx != NULL);
if (to_ctx == from_ctx) {
DUK_ERROR(to_thr, DUK_ERR_API_ERROR, DUK_STR_INVALID_CONTEXT);
return;
}
if ((count < 0) ||