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Introduce js_empty_string #1147

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Merged
merged 1 commit into from
Sep 1, 2025
+24 −18
Merged

Introduce js_empty_string #1147

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42 changes: 24 additions & 18 deletions quickjs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3622,6 +3622,12 @@ int JS_NewClass(JSRuntime *rt, JSClassID class_id, const JSClassDef *class_def)
return ret;
}

static inline JSValue js_empty_string(JSRuntime *rt)
{
JSAtomStruct *p = rt->atom_array[JS_ATOM_empty_string];
return js_dup(JS_MKPTR(JS_TAG_STRING, p));
}

// XXX: `buf` contains raw 8-bit data, no UTF-8 decoding is performed
// XXX: no special case for len == 0
static JSValue js_new_string8_len(JSContext *ctx, const char *buf, int len)
Expand Down Expand Up @@ -3670,7 +3676,7 @@ static JSValue js_sub_string(JSContext *ctx, JSString *p, int start, int end)
return js_dup(JS_MKPTR(JS_TAG_STRING, p));
}
if (len <= 0) {
return JS_AtomToString(ctx, JS_ATOM_empty_string);
return js_empty_string(ctx->rt);
}
if (p->is_wide_char) {
JSString *str;
Expand Down Expand Up @@ -4007,7 +4013,7 @@ static JSValue string_buffer_end(StringBuffer *s)
if (s->len == 0) {
js_free(s->ctx, str);
s->str = NULL;
return JS_AtomToString(s->ctx, JS_ATOM_empty_string);
return js_empty_string(s->ctx->rt);
}
if (s->len < s->size) {
/* smaller size so js_realloc should not fail, but OK if it does */
Expand Down Expand Up @@ -4038,7 +4044,7 @@ JSValue JS_NewStringLen(JSContext *ctx, const char *buf, size_t buf_len)
int kind;

if (buf_len <= 0) {
return JS_AtomToString(ctx, JS_ATOM_empty_string);
return js_empty_string(ctx->rt);
}
/* Compute string kind and length: 7-bit, 8-bit, 16-bit, 16-bit UTF-16 */
kind = utf8_scan(buf, buf_len, &len);
Expand Down Expand Up @@ -4078,7 +4084,7 @@ JSValue JS_NewTwoByteString(JSContext *ctx, const uint16_t *buf, size_t len)
JSString *str;

if (!len)
return JS_AtomToString(ctx, JS_ATOM_empty_string);
return js_empty_string(ctx->rt);
str = js_alloc_string(ctx, len, 1);
if (!str)
return JS_EXCEPTION;
Expand Down Expand Up @@ -16614,7 +16620,7 @@ static JSValue JS_CallInternal(JSContext *caller_ctx, JSValueConst func_obj,
goto exception;
BREAK;
CASE(OP_push_empty_string):
*sp++ = JS_AtomToString(ctx, JS_ATOM_empty_string);
*sp++ = js_empty_string(rt);
BREAK;
CASE(OP_get_length):
{
Expand Down Expand Up @@ -39362,7 +39368,7 @@ static JSValue js_function_bind(JSContext *ctx, JSValueConst this_val,
goto exception;
if (!JS_IsString(name1)) {
JS_FreeValue(ctx, name1);
name1 = JS_AtomToString(ctx, JS_ATOM_empty_string);
name1 = js_empty_string(ctx->rt);
}
name1 = JS_ConcatString3(ctx, "bound ", name1, "");
if (JS_IsException(name1))
Expand Down Expand Up @@ -39413,7 +39419,7 @@ static JSValue js_function_toString(JSContext *ctx, JSValueConst this_val,
suff = "() {\n [native code]\n}";
name = JS_GetProperty(ctx, this_val, JS_ATOM_name);
if (JS_IsUndefined(name))
name = JS_AtomToString(ctx, JS_ATOM_empty_string);
name = js_empty_string(ctx->rt);
return JS_ConcatString3(ctx, pref, name, suff);
}
}
Expand Down Expand Up @@ -39575,7 +39581,7 @@ static JSValue js_error_toString(JSContext *ctx, JSValueConst this_val,

msg = JS_GetProperty(ctx, this_val, JS_ATOM_message);
if (JS_IsUndefined(msg))
msg = JS_AtomToString(ctx, JS_ATOM_empty_string);
msg = js_empty_string(ctx->rt);
else
msg = JS_ToStringFree(ctx, msg);
if (JS_IsException(msg)) {
Expand Down Expand Up @@ -43051,7 +43057,7 @@ static JSValue js_string_constructor(JSContext *ctx, JSValueConst new_target,
{
JSValue val, obj;
if (argc == 0) {
val = JS_AtomToString(ctx, JS_ATOM_empty_string);
val = js_empty_string(ctx->rt);
} else {
if (JS_IsUndefined(new_target) && JS_IsSymbol(argv[0])) {
JSAtomStruct *p = JS_VALUE_GET_PTR(argv[0]);
Expand Down Expand Up @@ -43301,7 +43307,7 @@ static JSValue js_string_charAt(JSContext *ctx, JSValueConst this_val,
return JS_EXCEPTION;
}
if (idx < 0 || idx >= p->len) {
ret = JS_AtomToString(ctx, JS_ATOM_empty_string);
ret = js_empty_string(ctx->rt);
} else {
c = string_get(p, idx);
ret = js_new_string_char(ctx, c);
Expand Down Expand Up @@ -45331,7 +45337,7 @@ static JSValue js_regexp_constructor(JSContext *ctx, JSValueConst new_target,
flags = js_dup(flags1);
}
if (JS_IsUndefined(pattern)) {
pattern = JS_AtomToString(ctx, JS_ATOM_empty_string);
pattern = js_empty_string(ctx->rt);
} else {
val = pattern;
pattern = JS_ToString(ctx, val);
Expand Down Expand Up @@ -45373,7 +45379,7 @@ static JSValue js_regexp_compile(JSContext *ctx, JSValueConst this_val,
} else {
bc = JS_UNDEFINED;
if (JS_IsUndefined(pattern1))
pattern = JS_AtomToString(ctx, JS_ATOM_empty_string);
pattern = js_empty_string(ctx->rt);
else
pattern = JS_ToString(ctx, pattern1);
if (JS_IsException(pattern))
Expand Down Expand Up @@ -45531,7 +45537,7 @@ static JSValue js_regexp_get_flags(JSContext *ctx, JSValueConst this_val)
if (res)
*p++ = 'y';
if (p == str)
return JS_AtomToString(ctx, JS_ATOM_empty_string);
return js_empty_string(ctx->rt);
return js_new_string8_len(ctx, str, p - str);

exception:
Expand Down Expand Up @@ -47256,7 +47262,7 @@ JSValue JS_JSONStringify(JSContext *ctx, JSValueConst obj,
jsc->property_list = JS_UNDEFINED;
jsc->gap = JS_UNDEFINED;
jsc->b = &b_s;
jsc->empty = JS_AtomToString(ctx, JS_ATOM_empty_string);
jsc->empty = js_empty_string(ctx->rt);
ret = JS_UNDEFINED;
wrapper = JS_UNDEFINED;

Expand Down Expand Up @@ -52300,7 +52306,7 @@ static JSValue get_date_string(JSContext *ctx, JSValueConst this_val,
}
if (!pos) {
// XXX: should throw exception?
return JS_AtomToString(ctx, JS_ATOM_empty_string);
return js_empty_string(ctx->rt);
}
return js_new_string8_len(ctx, buf, pos);
}
Expand Down Expand Up @@ -53320,7 +53326,7 @@ static void JS_AddIntrinsicBasicObjects(JSContext *ctx)
JS_NewAtomString(ctx, native_error_name[i]),
JS_PROP_WRITABLE | JS_PROP_CONFIGURABLE);
JS_DefinePropertyValue(ctx, proto, JS_ATOM_message,
JS_AtomToString(ctx, JS_ATOM_empty_string),
js_empty_string(ctx->rt),
JS_PROP_WRITABLE | JS_PROP_CONFIGURABLE);
ctx->native_error_proto[i] = proto;
}
Expand Down Expand Up @@ -53515,7 +53521,7 @@ void JS_AddIntrinsicBaseObjects(JSContext *ctx)
/* String */
ctx->class_proto[JS_CLASS_STRING] = JS_NewObjectProtoClass(ctx, ctx->class_proto[JS_CLASS_OBJECT],
JS_CLASS_STRING);
JS_SetObjectData(ctx, ctx->class_proto[JS_CLASS_STRING], JS_AtomToString(ctx, JS_ATOM_empty_string));
JS_SetObjectData(ctx, ctx->class_proto[JS_CLASS_STRING], js_empty_string(ctx->rt));
obj = JS_NewGlobalCConstructor(ctx, "String", js_string_constructor, 1,
ctx->class_proto[JS_CLASS_STRING]);
JS_SetPropertyFunctionList(ctx, obj, js_string_funcs,
Expand Down Expand Up @@ -57838,7 +57844,7 @@ static JSValue js_domexception_constructor0(JSContext *ctx, JSValueConst new_tar
if (!JS_IsUndefined(argv[0]))
message = JS_ToString(ctx, argv[0]);
else
message = JS_AtomToString(ctx, JS_ATOM_empty_string);
message = js_empty_string(ctx->rt);
if (JS_IsException(message))
goto fail1;
if (!JS_IsUndefined(argv[1]))
Expand Down
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