OVMS3/OVMS.V3/components/duktape/src-separate/duk_error_augment.c

588 lines
20 KiB
C

/*
* Augmenting errors at their creation site and their throw site.
*
* When errors are created, traceback data is added by built-in code
* and a user error handler (if defined) can process or replace the
* error. Similarly, when errors are thrown, a user error handler
* (if defined) can process or replace the error.
*
* Augmentation and other processing at error creation time is nice
* because an error is only created once, but it may be thrown and
* rethrown multiple times. User error handler registered for processing
* an error at its throw site must be careful to handle rethrowing in
* a useful manner.
*
* Error augmentation may throw an internal error (e.g. alloc error).
*
* ECMAScript allows throwing any values, so all values cannot be
* augmented. Currently, the built-in augmentation at error creation
* only augments error values which are Error instances (= have the
* built-in Error.prototype in their prototype chain) and are also
* extensible. User error handlers have no limitations in this respect.
*/
#include "duk_internal.h"
/*
* Helper for calling a user error handler.
*
* 'thr' must be the currently active thread; the error handler is called
* in its context. The valstack of 'thr' must have the error value on
* top, and will be replaced by another error value based on the return
* value of the error handler.
*
* The helper calls duk_handle_call() recursively in protected mode.
* Before that call happens, no longjmps should happen; as a consequence,
* we must assume that the valstack contains enough temporary space for
* arguments and such.
*
* While the error handler runs, any errors thrown will not trigger a
* recursive error handler call (this is implemented using a heap level
* flag which will "follow" through any coroutines resumed inside the
* error handler). If the error handler is not callable or throws an
* error, the resulting error replaces the original error (for Duktape
* internal errors, duk_error_throw.c further substitutes this error with
* a DoubleError which is not ideal). This would be easy to change and
* even signal to the caller.
*
* The user error handler is stored in 'Duktape.errCreate' or
* 'Duktape.errThrow' depending on whether we're augmenting the error at
* creation or throw time. There are several alternatives to this approach,
* see doc/error-objects.rst for discussion.
*
* Note: since further longjmp()s may occur while calling the error handler
* (for many reasons, e.g. a labeled 'break' inside the handler), the
* caller can make no assumptions on the thr->heap->lj state after the
* call (this affects especially duk_error_throw.c). This is not an issue
* as long as the caller writes to the lj state only after the error handler
* finishes.
*/
#if defined(DUK_USE_ERRTHROW) || defined(DUK_USE_ERRCREATE)
DUK_LOCAL void duk__err_augment_user(duk_hthread *thr, duk_small_uint_t stridx_cb) {
duk_tval *tv_hnd;
duk_int_t rc;
DUK_ASSERT(thr != NULL);
DUK_ASSERT(thr->heap != NULL);
DUK_ASSERT_STRIDX_VALID(stridx_cb);
if (thr->heap->augmenting_error) {
DUK_D(DUK_DPRINT("recursive call to error augmentation, ignore"));
return;
}
/*
* Check whether or not we have an error handler.
*
* We must be careful of not triggering an error when looking up the
* property. For instance, if the property is a getter, we don't want
* to call it, only plain values are allowed. The value, if it exists,
* is not checked. If the value is not a function, a TypeError happens
* when it is called and that error replaces the original one.
*/
DUK_ASSERT_VALSTACK_SPACE(thr, 4); /* 3 entries actually needed below */
/* [ ... errval ] */
if (thr->builtins[DUK_BIDX_DUKTAPE] == NULL) {
/* When creating built-ins, some of the built-ins may not be set
* and we want to tolerate that when throwing errors.
*/
DUK_DD(DUK_DDPRINT("error occurred when DUK_BIDX_DUKTAPE is NULL, ignoring"));
return;
}
tv_hnd = duk_hobject_find_entry_tval_ptr_stridx(thr->heap,
thr->builtins[DUK_BIDX_DUKTAPE],
stridx_cb);
if (tv_hnd == NULL) {
DUK_DD(DUK_DDPRINT("error handler does not exist or is not a plain value: %!T",
(duk_tval *) tv_hnd));
return;
}
DUK_DDD(DUK_DDDPRINT("error handler dump (callability not checked): %!T",
(duk_tval *) tv_hnd));
duk_push_tval(thr, tv_hnd);
/* [ ... errval errhandler ] */
duk_insert(thr, -2); /* -> [ ... errhandler errval ] */
duk_push_undefined(thr);
duk_insert(thr, -2); /* -> [ ... errhandler undefined(= this) errval ] */
/* [ ... errhandler undefined errval ] */
/*
* heap->augmenting_error prevents recursive re-entry and also causes
* call handling to use a larger (but not unbounded) call stack limit
* for the duration of error augmentation.
*
* We ignore errors now: a success return and an error value both
* replace the original error value. (This would be easy to change.)
*/
DUK_ASSERT(thr->heap->augmenting_error == 0);
thr->heap->augmenting_error = 1;
rc = duk_pcall_method(thr, 1);
DUK_UNREF(rc); /* no need to check now: both success and error are OK */
DUK_ASSERT(thr->heap->augmenting_error == 1);
thr->heap->augmenting_error = 0;
/* [ ... errval ] */
}
#endif /* DUK_USE_ERRTHROW || DUK_USE_ERRCREATE */
/*
* Add ._Tracedata to an error on the stack top.
*/
#if defined(DUK_USE_TRACEBACKS)
DUK_LOCAL void duk__add_traceback(duk_hthread *thr, duk_hthread *thr_callstack, const char *c_filename, duk_int_t c_line, duk_small_uint_t flags) {
duk_activation *act;
duk_int_t depth;
duk_int_t arr_size;
duk_tval *tv;
duk_hstring *s;
duk_uint32_t u32;
duk_double_t d;
DUK_ASSERT(thr != NULL);
DUK_ASSERT(thr_callstack != NULL);
/* [ ... error ] */
/*
* The traceback format is pretty arcane in an attempt to keep it compact
* and cheap to create. It may change arbitrarily from version to version.
* It should be decoded/accessed through version specific accessors only.
*
* See doc/error-objects.rst.
*/
DUK_DDD(DUK_DDDPRINT("adding traceback to object: %!T",
(duk_tval *) duk_get_tval(thr, -1)));
/* Preallocate array to correct size, so that we can just write out
* the _Tracedata values into the array part.
*/
act = thr->callstack_curr;
depth = DUK_USE_TRACEBACK_DEPTH;
DUK_ASSERT(thr_callstack->callstack_top <= DUK_INT_MAX); /* callstack limits */
if (depth > (duk_int_t) thr_callstack->callstack_top) {
depth = (duk_int_t) thr_callstack->callstack_top;
}
if (depth > 0) {
if (flags & DUK_AUGMENT_FLAG_SKIP_ONE) {
DUK_ASSERT(act != NULL);
act = act->parent;
depth--;
}
}
arr_size = depth * 2;
if (thr->compile_ctx != NULL && thr->compile_ctx->h_filename != NULL) {
arr_size += 2;
}
if (c_filename) {
/* We need the C filename to be interned before getting the
* array part pointer to avoid any GC interference while the
* array part is populated.
*/
duk_push_string(thr, c_filename);
arr_size += 2;
}
/* XXX: Uninitialized would be OK. Maybe add internal primitive to
* push bare duk_harray with size?
*/
DUK_D(DUK_DPRINT("preallocated _Tracedata to %ld items", (long) arr_size));
tv = duk_push_harray_with_size_outptr(thr, (duk_uint32_t) arr_size);
duk_clear_prototype(thr, -1);
DUK_ASSERT(duk_is_bare_object(thr, -1));
DUK_ASSERT(arr_size == 0 || tv != NULL);
/* Compiler SyntaxErrors (and other errors) come first, and are
* blamed by default (not flagged "noblame").
*/
if (thr->compile_ctx != NULL && thr->compile_ctx->h_filename != NULL) {
s = thr->compile_ctx->h_filename;
DUK_TVAL_SET_STRING(tv, s);
DUK_HSTRING_INCREF(thr, s);
tv++;
u32 = (duk_uint32_t) thr->compile_ctx->curr_token.start_line; /* (flags<<32) + (line), flags = 0 */
DUK_TVAL_SET_U32(tv, u32);
tv++;
}
/* Filename/line from C macros (__FILE__, __LINE__) are added as an
* entry with a special format: (string, number). The number contains
* the line and flags.
*/
/* [ ... error c_filename? arr ] */
if (c_filename) {
DUK_ASSERT(DUK_TVAL_IS_STRING(thr->valstack_top - 2));
s = DUK_TVAL_GET_STRING(thr->valstack_top - 2); /* interned c_filename */
DUK_ASSERT(s != NULL);
DUK_TVAL_SET_STRING(tv, s);
DUK_HSTRING_INCREF(thr, s);
tv++;
d = ((flags & DUK_AUGMENT_FLAG_NOBLAME_FILELINE) ? ((duk_double_t) DUK_TB_FLAG_NOBLAME_FILELINE) * DUK_DOUBLE_2TO32 : 0.0) +
(duk_double_t) c_line;
DUK_TVAL_SET_DOUBLE(tv, d);
tv++;
}
/* Traceback depth doesn't take into account the filename/line
* special handling above (intentional).
*/
for (; depth-- > 0; act = act->parent) {
duk_uint32_t pc;
duk_tval *tv_src;
/* [... arr] */
DUK_ASSERT(act != NULL); /* depth check above, assumes book-keeping is correct */
DUK_ASSERT_DISABLE(act->pc >= 0); /* unsigned */
/* Add function object. */
tv_src = &act->tv_func; /* object (function) or lightfunc */
DUK_ASSERT(DUK_TVAL_IS_OBJECT(tv_src) || DUK_TVAL_IS_LIGHTFUNC(tv_src));
DUK_TVAL_SET_TVAL(tv, tv_src);
DUK_TVAL_INCREF(thr, tv);
tv++;
/* Add a number containing: pc, activation flags.
*
* PC points to next instruction, find offending PC. Note that
* PC == 0 for native code.
*/
pc = (duk_uint32_t) duk_hthread_get_act_prev_pc(thr_callstack, act);
DUK_ASSERT_DISABLE(pc >= 0); /* unsigned */
DUK_ASSERT((duk_double_t) pc < DUK_DOUBLE_2TO32); /* assume PC is at most 32 bits and non-negative */
d = ((duk_double_t) act->flags) * DUK_DOUBLE_2TO32 + (duk_double_t) pc;
DUK_TVAL_SET_DOUBLE(tv, d);
tv++;
}
#if defined(DUK_USE_ASSERTIONS)
{
duk_harray *a;
a = (duk_harray *) duk_known_hobject(thr, -1);
DUK_ASSERT(a != NULL);
DUK_ASSERT((duk_uint32_t) (tv - DUK_HOBJECT_A_GET_BASE(thr->heap, (duk_hobject *) a)) == a->length);
DUK_ASSERT(a->length == (duk_uint32_t) arr_size);
DUK_ASSERT(duk_is_bare_object(thr, -1));
}
#endif
/* [ ... error c_filename? arr ] */
if (c_filename) {
duk_remove_m2(thr);
}
/* [ ... error arr ] */
duk_xdef_prop_stridx_short_wec(thr, -2, DUK_STRIDX_INT_TRACEDATA); /* -> [ ... error ] */
}
#endif /* DUK_USE_TRACEBACKS */
/*
* Add .fileName and .lineNumber to an error on the stack top.
*/
#if defined(DUK_USE_AUGMENT_ERROR_CREATE) && !defined(DUK_USE_TRACEBACKS)
DUK_LOCAL void duk__add_fileline(duk_hthread *thr, duk_hthread *thr_callstack, const char *c_filename, duk_int_t c_line, duk_small_uint_t flags) {
#if defined(DUK_USE_ASSERTIONS)
duk_int_t entry_top;
#endif
#if defined(DUK_USE_ASSERTIONS)
entry_top = duk_get_top(thr);
#endif
/*
* If tracebacks are disabled, 'fileName' and 'lineNumber' are added
* as plain own properties. Since Error.prototype has accessors of
* the same name, we need to define own properties directly (cannot
* just use e.g. duk_put_prop_stridx). Existing properties are not
* overwritten in case they already exist.
*/
if (thr->compile_ctx != NULL && thr->compile_ctx->h_filename != NULL) {
/* Compiler SyntaxError (or other error) gets the primary blame.
* Currently no flag to prevent blaming.
*/
duk_push_uint(thr, (duk_uint_t) thr->compile_ctx->curr_token.start_line);
duk_push_hstring(thr, thr->compile_ctx->h_filename);
} else if (c_filename && (flags & DUK_AUGMENT_FLAG_NOBLAME_FILELINE) == 0) {
/* C call site gets blamed next, unless flagged not to do so.
* XXX: file/line is disabled in minimal builds, so disable this
* too when appropriate.
*/
duk_push_int(thr, c_line);
duk_push_string(thr, c_filename);
} else {
/* Finally, blame the innermost callstack entry which has a
* .fileName property.
*/
duk_small_uint_t depth;
duk_uint32_t ecma_line;
duk_activation *act;
DUK_ASSERT(thr_callstack->callstack_top <= DUK_INT_MAX); /* callstack limits */
depth = DUK_USE_TRACEBACK_DEPTH;
if (depth > thr_callstack->callstack_top) {
depth = thr_callstack->callstack_top;
}
for (act = thr_callstack->callstack_curr; depth-- > 0; act = act->parent) {
duk_hobject *func;
duk_uint32_t pc;
DUK_ASSERT(act != NULL);
func = DUK_ACT_GET_FUNC(act);
if (func == NULL) {
/* Lightfunc, not blamed now. */
continue;
}
/* PC points to next instruction, find offending PC,
* PC == 0 for native code.
*/
pc = duk_hthread_get_act_prev_pc(thr, act); /* thr argument only used for thr->heap, so specific thread doesn't matter */
DUK_UNREF(pc);
DUK_ASSERT_DISABLE(pc >= 0); /* unsigned */
DUK_ASSERT((duk_double_t) pc < DUK_DOUBLE_2TO32); /* assume PC is at most 32 bits and non-negative */
duk_push_hobject(thr, func);
/* [ ... error func ] */
duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_FILE_NAME);
if (!duk_is_string_notsymbol(thr, -1)) {
duk_pop_2(thr);
continue;
}
/* [ ... error func fileName ] */
ecma_line = 0;
#if defined(DUK_USE_PC2LINE)
if (DUK_HOBJECT_IS_COMPFUNC(func)) {
ecma_line = duk_hobject_pc2line_query(thr, -2, (duk_uint_fast32_t) pc);
} else {
/* Native function, no relevant lineNumber. */
}
#endif /* DUK_USE_PC2LINE */
duk_push_u32(thr, ecma_line);
/* [ ... error func fileName lineNumber ] */
duk_replace(thr, -3);
/* [ ... error lineNumber fileName ] */
goto define_props;
}
/* No activation matches, use undefined for both .fileName and
* .lineNumber (matches what we do with a _Tracedata based
* no-match lookup.
*/
duk_push_undefined(thr);
duk_push_undefined(thr);
}
define_props:
/* [ ... error lineNumber fileName ] */
#if defined(DUK_USE_ASSERTIONS)
DUK_ASSERT(duk_get_top(thr) == entry_top + 2);
#endif
duk_xdef_prop_stridx_short(thr, -3, DUK_STRIDX_FILE_NAME, DUK_PROPDESC_FLAGS_C | DUK_PROPDESC_FLAG_NO_OVERWRITE);
duk_xdef_prop_stridx_short(thr, -2, DUK_STRIDX_LINE_NUMBER, DUK_PROPDESC_FLAGS_C | DUK_PROPDESC_FLAG_NO_OVERWRITE);
}
#endif /* DUK_USE_AUGMENT_ERROR_CREATE && !DUK_USE_TRACEBACKS */
/*
* Add line number to a compiler error.
*/
#if defined(DUK_USE_AUGMENT_ERROR_CREATE)
DUK_LOCAL void duk__add_compiler_error_line(duk_hthread *thr) {
/* Append a "(line NNN)" to the "message" property of any error
* thrown during compilation. Usually compilation errors are
* SyntaxErrors but they can also be out-of-memory errors and
* the like.
*/
/* [ ... error ] */
DUK_ASSERT(duk_is_object(thr, -1));
if (!(thr->compile_ctx != NULL && thr->compile_ctx->h_filename != NULL)) {
return;
}
DUK_DDD(DUK_DDDPRINT("compile error, before adding line info: %!T",
(duk_tval *) duk_get_tval(thr, -1)));
if (duk_get_prop_stridx_short(thr, -1, DUK_STRIDX_MESSAGE)) {
duk_bool_t at_end;
/* Best guesstimate that error occurred at end of input, token
* truncated by end of input, etc.
*/
#if 0
at_end = (thr->compile_ctx->curr_token.start_offset + 1 >= thr->compile_ctx->lex.input_length);
at_end = (thr->compile_ctx->lex.window[0].codepoint < 0 || thr->compile_ctx->lex.window[1].codepoint < 0);
#endif
at_end = (thr->compile_ctx->lex.window[0].codepoint < 0);
DUK_D(DUK_DPRINT("syntax error, determined at_end=%ld; curr_token.start_offset=%ld, "
"lex.input_length=%ld, window[0].codepoint=%ld, window[1].codepoint=%ld",
(long) at_end,
(long) thr->compile_ctx->curr_token.start_offset,
(long) thr->compile_ctx->lex.input_length,
(long) thr->compile_ctx->lex.window[0].codepoint,
(long) thr->compile_ctx->lex.window[1].codepoint));
duk_push_sprintf(thr, " (line %ld%s)",
(long) thr->compile_ctx->curr_token.start_line,
at_end ? ", end of input" : "");
duk_concat(thr, 2);
duk_put_prop_stridx_short(thr, -2, DUK_STRIDX_MESSAGE);
} else {
duk_pop(thr);
}
DUK_DDD(DUK_DDDPRINT("compile error, after adding line info: %!T",
(duk_tval *) duk_get_tval(thr, -1)));
}
#endif /* DUK_USE_AUGMENT_ERROR_CREATE */
/*
* Augment an error being created using Duktape specific properties
* like _Tracedata or .fileName/.lineNumber.
*/
#if defined(DUK_USE_AUGMENT_ERROR_CREATE)
DUK_LOCAL void duk__err_augment_builtin_create(duk_hthread *thr, duk_hthread *thr_callstack, const char *c_filename, duk_int_t c_line, duk_hobject *obj, duk_small_uint_t flags) {
#if defined(DUK_USE_ASSERTIONS)
duk_int_t entry_top;
#endif
#if defined(DUK_USE_ASSERTIONS)
entry_top = duk_get_top(thr);
#endif
DUK_ASSERT(obj != NULL);
DUK_UNREF(obj); /* unreferenced w/o tracebacks */
duk__add_compiler_error_line(thr);
#if defined(DUK_USE_TRACEBACKS)
/* If tracebacks are enabled, the '_Tracedata' property is the only
* thing we need: 'fileName' and 'lineNumber' are virtual properties
* which use '_Tracedata'. (Check _Tracedata only as own property.)
*/
if (duk_hobject_find_entry_tval_ptr_stridx(thr->heap, obj, DUK_STRIDX_INT_TRACEDATA) != NULL) {
DUK_DDD(DUK_DDDPRINT("error value already has a '_Tracedata' property, not modifying it"));
} else {
duk__add_traceback(thr, thr_callstack, c_filename, c_line, flags);
}
#else
/* Without tracebacks the concrete .fileName and .lineNumber need
* to be added directly.
*/
duk__add_fileline(thr, thr_callstack, c_filename, c_line, flags);
#endif
#if defined(DUK_USE_ASSERTIONS)
DUK_ASSERT(duk_get_top(thr) == entry_top);
#endif
}
#endif /* DUK_USE_AUGMENT_ERROR_CREATE */
/*
* Augment an error at creation time with _Tracedata/fileName/lineNumber
* and allow a user error handler (if defined) to process/replace the error.
* The error to be augmented is at the stack top.
*
* thr: thread containing the error value
* thr_callstack: thread which should be used for generating callstack etc.
* c_filename: C __FILE__ related to the error
* c_line: C __LINE__ related to the error
* flags & DUK_AUGMENT_FLAG_NOBLAME_FILELINE:
* if true, don't fileName/line as error source, otherwise use traceback
* (needed because user code filename/line are reported but internal ones
* are not)
*/
#if defined(DUK_USE_AUGMENT_ERROR_CREATE)
DUK_INTERNAL void duk_err_augment_error_create(duk_hthread *thr, duk_hthread *thr_callstack, const char *c_filename, duk_int_t c_line, duk_small_uint_t flags) {
duk_hobject *obj;
DUK_ASSERT(thr != NULL);
DUK_ASSERT(thr_callstack != NULL);
/* [ ... error ] */
/*
* Criteria for augmenting:
*
* - augmentation enabled in build (naturally)
* - error value internal prototype chain contains the built-in
* Error prototype object (i.e. 'val instanceof Error')
*
* Additional criteria for built-in augmenting:
*
* - error value is an extensible object
*/
obj = duk_get_hobject(thr, -1);
if (!obj) {
DUK_DDD(DUK_DDDPRINT("value is not an object, skip both built-in and user augment"));
return;
}
if (!duk_hobject_prototype_chain_contains(thr, obj, thr->builtins[DUK_BIDX_ERROR_PROTOTYPE], 1 /*ignore_loop*/)) {
/* If the value has a prototype loop, it's critical not to
* throw here. Instead, assume the value is not to be
* augmented.
*/
DUK_DDD(DUK_DDDPRINT("value is not an error instance, skip both built-in and user augment"));
return;
}
if (DUK_HOBJECT_HAS_EXTENSIBLE(obj)) {
DUK_DDD(DUK_DDDPRINT("error meets criteria, built-in augment"));
duk__err_augment_builtin_create(thr, thr_callstack, c_filename, c_line, obj, flags);
} else {
DUK_DDD(DUK_DDDPRINT("error does not meet criteria, no built-in augment"));
}
/* [ ... error ] */
#if defined(DUK_USE_ERRCREATE)
duk__err_augment_user(thr, DUK_STRIDX_ERR_CREATE);
#endif
}
#endif /* DUK_USE_AUGMENT_ERROR_CREATE */
/*
* Augment an error at throw time; allow a user error handler (if defined)
* to process/replace the error. The error to be augmented is at the
* stack top.
*/
#if defined(DUK_USE_AUGMENT_ERROR_THROW)
DUK_INTERNAL void duk_err_augment_error_throw(duk_hthread *thr) {
#if defined(DUK_USE_ERRTHROW)
duk__err_augment_user(thr, DUK_STRIDX_ERR_THROW);
#endif /* DUK_USE_ERRTHROW */
}
#endif /* DUK_USE_AUGMENT_ERROR_THROW */