Merge pull request #1123 from svaarala/api-set-length

Add duk_set_length() to correspond with duk_get_length()

RELEASES.rst

@@ -1976,6 +1976,9 @@ Planned
 * Add duk_inspect_callstack_entry() to provide internal information about a
   callstack entry; the output matches Duktape.act() (GH-1128)
 
+* Add duk_set_length() API call and change duk_get_length() limits from
+  uint32 to size_t supported range (GH-1123)
+
 * Add ability to perform an indirect debugger Eval with non-empty callstack by
   sending null for the callstack level (GH-747)
 

doc/release-notes-v2-0.rst

@@ -1044,6 +1044,9 @@ Other incompatible changes
   previously an error was thrown.  This situation never occurs for standard
   Ecmascript strings or valid UTF-8 strings.
 
+* ``duk_get_length()`` now allows the ``size_t`` rather than the unsigned 32-bit
+  integer range for the target value's ``.length``.
+
 * Legacy octal literal handling has been improved to match more closely with
   ES6 Annex B.  Octal look-alike decimal literals like "0778" and "0778.123"
   are now allowed.

src-input/duk_api_internal.h

@@ -258,9 +258,6 @@ DUK_INTERNAL_DECL void duk_xdef_prop_stridx_builtin(duk_context *ctx, duk_idx_t
 
 DUK_INTERNAL_DECL void duk_xdef_prop_stridx_thrower(duk_context *ctx, duk_idx_t obj_idx, duk_small_uint_t stridx);  /* [] -> [] */
 
-/* Set object 'length'. */
-DUK_INTERNAL_DECL void duk_set_length(duk_context *ctx, duk_idx_t idx, duk_size_t length);
-
 DUK_INTERNAL_DECL void duk_pack(duk_context *ctx, duk_idx_t count);
 #if 0
 DUK_INTERNAL_DECL void duk_unpack(duk_context *ctx);

src-input/duk_api_public.h.in

@@ -642,6 +642,7 @@ DUK_EXTERNAL_DECL duk_c_function duk_get_c_function(duk_context *ctx, duk_idx_t
 DUK_EXTERNAL_DECL duk_context *duk_get_context(duk_context *ctx, duk_idx_t idx);
 DUK_EXTERNAL_DECL void *duk_get_heapptr(duk_context *ctx, duk_idx_t idx);
 DUK_EXTERNAL_DECL duk_size_t duk_get_length(duk_context *ctx, duk_idx_t idx);
+DUK_EXTERNAL_DECL void duk_set_length(duk_context *ctx, duk_idx_t idx, duk_size_t len);
 
 /*
  *  Require operations: no coercion, throw error if index or type

src-input/duk_api_stack.c

@@ -1827,16 +1827,26 @@ DUK_EXTERNAL duk_size_t duk_get_length(duk_context *ctx, duk_idx_t idx) {
 	case DUK_TAG_BOOLEAN:
 	case DUK_TAG_POINTER:
 		return 0;
+#if defined(DUK_USE_PREFER_SIZE)
+	/* All of these types (besides object) have a virtual, non-configurable
+	 * .length property which is within size_t range so we can just look it
+	 * up without specific type checks.
+	 */
+	case DUK_TAG_STRING:
+	case DUK_TAG_BUFFER:
+	case DUK_TAG_LIGHTFUNC: {
+		duk_size_t ret;
+		duk_get_prop_stridx(ctx, idx, DUK_STRIDX_LENGTH);
+		ret = (duk_size_t) duk_to_number_m1(ctx);
+		duk_pop(ctx);
+		return ret;
+	}
+#else  /* DUK_USE_PREFER_SIZE */
 	case DUK_TAG_STRING: {
 		duk_hstring *h = DUK_TVAL_GET_STRING(tv);
 		DUK_ASSERT(h != NULL);
 		return (duk_size_t) DUK_HSTRING_GET_CHARLEN(h);
 	}
-	case DUK_TAG_OBJECT: {
-		duk_hobject *h = DUK_TVAL_GET_OBJECT(tv);
-		DUK_ASSERT(h != NULL);
-		return (duk_size_t) duk_hobject_get_length((duk_hthread *) ctx, h);
-	}
 	case DUK_TAG_BUFFER: {
 		duk_hbuffer *h = DUK_TVAL_GET_BUFFER(tv);
 		DUK_ASSERT(h != NULL);
@@ -1847,6 +1857,12 @@ DUK_EXTERNAL duk_size_t duk_get_length(duk_context *ctx, duk_idx_t idx) {
 		lf_flags = DUK_TVAL_GET_LIGHTFUNC_FLAGS(tv);
 		return (duk_size_t) DUK_LFUNC_FLAGS_GET_LENGTH(lf_flags);
 	}
+#endif  /* DUK_USE_PREFER_SIZE */
+	case DUK_TAG_OBJECT: {
+		duk_hobject *h = DUK_TVAL_GET_OBJECT(tv);
+		DUK_ASSERT(h != NULL);
+		return (duk_size_t) duk_hobject_get_length((duk_hthread *) ctx, h);
+	}
 #if defined(DUK_USE_FASTINT)
 	case DUK_TAG_FASTINT:
 #endif
@@ -1859,7 +1875,6 @@ DUK_EXTERNAL duk_size_t duk_get_length(duk_context *ctx, duk_idx_t idx) {
 	DUK_UNREACHABLE();
 }
 
-
 /*
  *  duk_known_xxx() helpers
  *
@@ -1913,18 +1928,12 @@ DUK_INTERNAL duk_hnatfunc *duk_known_hnatfunc(duk_context *ctx, duk_idx_t idx) {
 	return (duk_hnatfunc *) duk__known_heaphdr(ctx, idx);
 }
 
-DUK_INTERNAL void duk_set_length(duk_context *ctx, duk_idx_t idx, duk_size_t length) {
-	duk_hthread *thr = (duk_hthread *) ctx;
-	duk_hobject *h;
-
+DUK_EXTERNAL void duk_set_length(duk_context *ctx, duk_idx_t idx, duk_size_t len) {
 	DUK_ASSERT_CTX_VALID(ctx);
 
-	h = duk_get_hobject(ctx, idx);
-	if (!h) {
-		return;
-	}
-
-	duk_hobject_set_length(thr, h, (duk_uint32_t) length);  /* XXX: typing */
+	idx = duk_normalize_index(ctx, idx);
+	duk_push_uint(ctx, (duk_uint_t) len);
+	duk_put_prop_stridx(ctx, idx, DUK_STRIDX_LENGTH);
 }
 
 /*

src-input/duk_bi_json.c

@@ -2472,7 +2472,7 @@ DUK_LOCAL duk_bool_t duk__json_stringify_fast_value(duk_json_enc_ctx *js_ctx, du
 				goto abort_fastpath;
 			}
 
-			arr_len = (duk_uint_fast32_t) duk_hobject_get_length(js_ctx->thr, obj);
+			arr_len = (duk_uint_fast32_t) ((duk_harray *) obj)->length;
 			asize = (duk_uint_fast32_t) DUK_HOBJECT_GET_ASIZE(obj);
 			/* Array part may be larger than 'length'; if so, iterate
 			 * only up to array 'length'.  Array part may also be smaller

src-input/duk_hobject.h

@@ -887,9 +887,7 @@ DUK_INTERNAL_DECL duk_bool_t duk_hobject_delprop_raw(duk_hthread *thr, duk_hobje
 DUK_INTERNAL_DECL duk_bool_t duk_hobject_hasprop_raw(duk_hthread *thr, duk_hobject *obj, duk_hstring *key);
 DUK_INTERNAL_DECL void duk_hobject_define_property_internal(duk_hthread *thr, duk_hobject *obj, duk_hstring *key, duk_small_uint_t flags);
 DUK_INTERNAL_DECL void duk_hobject_define_property_internal_arridx(duk_hthread *thr, duk_hobject *obj, duk_uarridx_t arr_idx, duk_small_uint_t flags);
-DUK_INTERNAL_DECL void duk_hobject_set_length(duk_hthread *thr, duk_hobject *obj, duk_uint32_t length);  /* XXX: duk_uarridx_t? */
-DUK_INTERNAL_DECL void duk_hobject_set_length_zero(duk_hthread *thr, duk_hobject *obj);
-DUK_INTERNAL_DECL duk_uint32_t duk_hobject_get_length(duk_hthread *thr, duk_hobject *obj);  /* XXX: duk_uarridx_t? */
+DUK_INTERNAL_DECL duk_size_t duk_hobject_get_length(duk_hthread *thr, duk_hobject *obj);
 
 /* helpers for defineProperty() and defineProperties() */
 DUK_INTERNAL_DECL

src-input/duk_hobject_props.c

@@ -4745,26 +4745,7 @@ DUK_INTERNAL void duk_hobject_define_property_internal_arridx(duk_hthread *thr,
  *  Internal helpers for managing object 'length'
  */
 
-/* XXX: awkward helpers */
-
-DUK_INTERNAL void duk_hobject_set_length(duk_hthread *thr, duk_hobject *obj, duk_uint32_t length) {
-	duk_context *ctx = (duk_context *) thr;
-	duk_push_hobject(ctx, obj);
-	duk_push_hstring_stridx(ctx, DUK_STRIDX_LENGTH);
-	duk_push_u32(ctx, length);
-	(void) duk_hobject_putprop(thr,
-	                           DUK_GET_TVAL_NEGIDX(ctx, -3),
-	                           DUK_GET_TVAL_NEGIDX(ctx, -2),
-	                           DUK_GET_TVAL_NEGIDX(ctx, -1),
-	                           0);
-	duk_pop_3(ctx);
-}
-
-DUK_INTERNAL void duk_hobject_set_length_zero(duk_hthread *thr, duk_hobject *obj) {
-	duk_hobject_set_length(thr, obj, 0);
-}
-
-DUK_INTERNAL duk_uint32_t duk_hobject_get_length(duk_hthread *thr, duk_hobject *obj) {
+DUK_INTERNAL duk_size_t duk_hobject_get_length(duk_hthread *thr, duk_hobject *obj) {
 	duk_context *ctx = (duk_context *) thr;
 	duk_double_t val;
 
@@ -4785,9 +4766,11 @@ DUK_INTERNAL duk_uint32_t duk_hobject_get_length(duk_hthread *thr, duk_hobject *
 	val = duk_to_number_m1(ctx);
 	duk_pop_3(ctx);
 
-	/* XXX: better check */
-	if (val >= 0.0 && val < DUK_DOUBLE_2TO32) {
-		return (duk_uint32_t) val;
+	/* This isn't part of Ecmascript semantics; return a value within
+	 * duk_size_t range, or 0 otherwise.
+	 */
+	if (val >= 0.0 && val <= (duk_double_t) DUK_SIZE_MAX) {
+		return (duk_size_t) val;
 	}
 	return 0;
 }

src-input/duk_js_compiler.c

@@ -585,11 +585,11 @@ DUK_LOCAL void duk__reset_func_for_pass2(duk_compiler_ctx *comp_ctx) {
 	 */
 	DUK_BW_RESET_SIZE(thr, &func->bw_code);
 
-	duk_hobject_set_length_zero(thr, func->h_consts);
+	duk_set_length(ctx, func->consts_idx, 0);
 	/* keep func->h_funcs; inner functions are not reparsed to avoid O(depth^2) parsing */
 	func->fnum_next = 0;
-	/* duk_hobject_set_length_zero(thr, func->h_funcs); */
-	duk_hobject_set_length_zero(thr, func->h_labelnames);
+	/* duk_set_length(ctx, func->funcs_idx, 0); */
+	duk_set_length(ctx, func->labelnames_idx, 0);
 	duk_hbuffer_reset(thr, func->h_labelinfos);
 	/* keep func->h_argnames; it is fixed for all passes */
 
@@ -2760,13 +2760,9 @@ DUK_LOCAL void duk__lookup_active_label(duk_compiler_ctx *comp_ctx, duk_hstring
 DUK_LOCAL void duk__reset_labels_to_length(duk_compiler_ctx *comp_ctx, duk_int_t len) {
 	duk_hthread *thr = comp_ctx->thr;
 	duk_context *ctx = (duk_context *) thr;
-	duk_size_t new_size;
 
-	/* XXX: duk_set_length */
-	new_size = sizeof(duk_labelinfo) * (duk_size_t) len;
-	duk_push_int(ctx, len);
-	duk_put_prop_stridx(ctx, comp_ctx->curr_func.labelnames_idx, DUK_STRIDX_LENGTH);
-	duk_hbuffer_resize(thr, comp_ctx->curr_func.h_labelinfos, new_size);
+	duk_set_length(ctx, comp_ctx->curr_func.labelnames_idx, (duk_size_t) len);
+	duk_hbuffer_resize(thr, comp_ctx->curr_func.h_labelinfos, sizeof(duk_labelinfo) * (duk_size_t) len);
 }
 
 /*

src-input/duk_js_executor.c

@@ -4787,7 +4787,7 @@ DUK_LOCAL DUK_NOINLINE void duk__js_execute_bytecode_inner(duk_hthread *entry_th
 			 * ToUint32() which is odd but happens now as a side effect of
 			 * 'arr_idx' type.
 			 */
-			duk_hobject_set_length(thr, duk_known_hobject(ctx, obj_idx), (duk_uint32_t) arr_idx);
+			duk_set_length(thr, obj_idx, (duk_size_t) (duk_uarridx_t) arr_idx);
 			break;
 		}
 

tests/api/test-get-length.c

@@ -59,13 +59,13 @@ void test(duk_context *ctx) {
 	duk_put_prop_string(ctx, -2, "length");
 
 	/* 8 */
-	duk_push_object(ctx);  /* length: outside 32-bit range but within range after ToInteger() */
-	duk_push_number(ctx, 4294967295.9);
+	duk_push_object(ctx);  /* length: just within 32-bit range */
+	duk_push_number(ctx, (duk_double_t) 0xffffffffUL);
 	duk_put_prop_string(ctx, -2, "length");
 
 	/* 9 */
-	duk_push_object(ctx);  /* length: outside 32-bit range */
-	duk_push_number(ctx, 4294967296);
+	duk_push_object(ctx);  /* length: outside size_t range */
+	duk_push_number(ctx, (duk_double_t) DUK_SIZE_MAX + 1.0);
 	duk_put_prop_string(ctx, -2, "length");
 
 	/* 10 */

tests/api/test-set-length.c

@@ -0,0 +1,50 @@
+/*===
+*** test_basic (duk_safe_call)
+["foo","bar","quux","bax"]
+["foo"]
+["foo",null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null]
+{"foo":123}
+{"foo":123,"length":123}
+final top: 0
+==> rc=0, result='undefined'
+===*/
+
+static duk_ret_t test_basic(duk_context *ctx, void *udata) {
+	(void) udata;
+
+	duk_eval_string(ctx, "[ 'foo', 'bar', 'quux', 'bax' ]");
+	duk_dup(ctx, -1);
+	printf("%s\n", duk_json_encode(ctx, -1));
+	duk_pop(ctx);
+
+	duk_set_length(ctx, -1, 1);
+	duk_dup(ctx, -1);
+	printf("%s\n", duk_json_encode(ctx, -1));
+	duk_pop(ctx);
+
+	duk_set_length(ctx, -1, 100);
+	duk_dup(ctx, -1);
+	printf("%s\n", duk_json_encode(ctx, -1));
+	duk_pop(ctx);
+
+	duk_pop(ctx);
+
+	duk_eval_string(ctx, "({ foo: 123 })");
+	duk_dup(ctx, -1);
+	printf("%s\n", duk_json_encode(ctx, -1));
+	duk_pop(ctx);
+
+	duk_set_length(ctx, -1, 123);
+	duk_dup(ctx, -1);
+	printf("%s\n", duk_json_encode(ctx, -1));
+	duk_pop(ctx);
+
+	duk_pop(ctx);
+
+	printf("final top: %ld\n", (long) duk_get_top(ctx));
+	return 0;
+}
+
+void test(duk_context *ctx) {
+	TEST_SAFE_CALL(test_basic);
+}

website/api/duk_get_length.yaml

@@ -11,7 +11,7 @@ summary: |
   <ul>
   <li>String: character length of string (<i>not</i> byte length)</li>
   <li>Object: <code>Math.floor(ToNumber(obj.length))</code> if result within
-              32-bit unsigned range; otherwise 0</li>
+              <code>duk_size_t</code> unsigned range; otherwise 0</li>
   <li>Buffer: byte length of buffer</li>
   <li>Other type or invalid stack index: 0</li>
   </ul>
@@ -28,4 +28,7 @@ example: |
 tags:
   - stack
 
+seealso:
+  - duk_set_length
+
 introduced: 1.0.0

website/api/duk_set_length.yaml

@@ -0,0 +1,23 @@
+name: duk_set_length
+
+proto: |
+  void duk_set_length(duk_context *ctx, duk_idx_t idx, duk_size_t len);
+
+stack: |
+  [ ... val! ... ]
+
+summary: |
+  <p>Set "length" for value at <code>idx</code>.  Equivalent to the Ecmascript
+  statement <code>obj.length = len;</code>.</p>
+
+example: |
+  /* Set array length to zero, deleting elements as a side effect. */
+  duk_set_length(ctx, -3, 0);
+
+tags:
+  - stack
+
+seealso:
+  - duk_get_length
+
+introduced: 2.0.0