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node-api: optimize napi_set_property for perf
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PR-URL: #50282
Reviewed-By: Vladimir Morozov <vmorozov@microsoft.com>
Reviewed-By: Michael Dawson <midawson@redhat.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
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mertcanaltin authored and targos committed Feb 15, 2024
1 parent fabd5c4 commit 66c11f3
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44 changes: 44 additions & 0 deletions doc/api/n-api.md
Original file line number Diff line number Diff line change
Expand Up @@ -3085,6 +3085,50 @@ The native string is copied.
The JavaScript `string` type is described in
[Section 6.1.4][] of the ECMAScript Language Specification.

#### `node_api_create_property_key_utf16`

<!-- YAML
added: REPLACEME
-->

> Stability: 1 - Experimental

```c
napi_status NAPI_CDECL node_api_create_property_key_utf16(napi_env env,
const char16_t* str,
size_t length,
napi_value* result);
```

* `[in] env`: The environment that the API is invoked under.
* `[in] str`: Character buffer representing a UTF16-LE-encoded string.
* `[in] length`: The length of the string in two-byte code units, or
`NAPI_AUTO_LENGTH` if it is null-terminated.
* `[out] result`: A `napi_value` representing an optimized JavaScript `string`
to be used as a property key for objects.

Returns `napi_ok` if the API succeeded.

This API creates an optimized JavaScript `string` value from
a UTF16-LE-encoded C string to be used as a property key for objects.
The native string is copied.

Many JavaScript engines including V8 use internalized strings as keys
to set and get property values. They typically use a hash table to create
and lookup such strings. While it adds some cost per key creation, it improves
the performance after that by enabling comparison of string pointers instead
of the whole strings.

If a new JavaScript string is intended to be used as a property key, then for
some JavaScript engines it will be more efficient to use
the `node_api_create_property_key_utf16` function.
Otherwise, use the `napi_create_string_utf16` or
`node_api_create_external_string_utf16` functions as there may be additional
overhead in creating/storing strings with this method.

The JavaScript `string` type is described in
[Section 6.1.4][] of the ECMAScript Language Specification.

### Functions to convert from Node-API to C types

#### `napi_get_array_length`
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7 changes: 7 additions & 0 deletions src/js_native_api.h
Original file line number Diff line number Diff line change
Expand Up @@ -111,6 +111,13 @@ node_api_create_external_string_utf16(napi_env env,
napi_value* result,
bool* copied);
#endif // NAPI_EXPERIMENTAL

#ifdef NAPI_EXPERIMENTAL
#define NODE_API_EXPERIMENTAL_HAS_PROPERTY_KEYS
NAPI_EXTERN napi_status NAPI_CDECL node_api_create_property_key_utf16(
napi_env env, const char16_t* str, size_t length, napi_value* result);
#endif // NAPI_EXPERIMENTAL

NAPI_EXTERN napi_status NAPI_CDECL napi_create_symbol(napi_env env,
napi_value description,
napi_value* result);
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12 changes: 12 additions & 0 deletions src/js_native_api_v8.cc
Original file line number Diff line number Diff line change
Expand Up @@ -1705,6 +1705,18 @@ napi_status NAPI_CDECL node_api_create_external_string_utf16(
});
}

napi_status NAPI_CDECL node_api_create_property_key_utf16(napi_env env,
const char16_t* str,
size_t length,
napi_value* result) {
return v8impl::NewString(env, str, length, result, [&](v8::Isolate* isolate) {
return v8::String::NewFromTwoByte(isolate,
reinterpret_cast<const uint16_t*>(str),
v8::NewStringType::kInternalized,
static_cast<int>(length));
});
}

napi_status NAPI_CDECL napi_create_double(napi_env env,
double value,
napi_value* result) {
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14 changes: 14 additions & 0 deletions test/js-native-api/test_string/test.js
Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,8 @@ assert.strictEqual(test_string.TestLatin1External(empty), empty);
assert.strictEqual(test_string.TestUtf16External(empty), empty);
assert.strictEqual(test_string.TestLatin1ExternalAutoLength(empty), empty);
assert.strictEqual(test_string.TestUtf16ExternalAutoLength(empty), empty);
assert.strictEqual(test_string.TestPropertyKeyUtf16(empty), empty);
assert.strictEqual(test_string.TestPropertyKeyUtf16AutoLength(empty), empty);
assert.strictEqual(test_string.Utf16Length(empty), 0);
assert.strictEqual(test_string.Utf8Length(empty), 0);

Expand All @@ -33,6 +35,8 @@ assert.strictEqual(test_string.TestUtf16ExternalAutoLength(str1), str1);
assert.strictEqual(test_string.TestLatin1Insufficient(str1), str1.slice(0, 3));
assert.strictEqual(test_string.TestUtf8Insufficient(str1), str1.slice(0, 3));
assert.strictEqual(test_string.TestUtf16Insufficient(str1), str1.slice(0, 3));
assert.strictEqual(test_string.TestPropertyKeyUtf16(str1), str1);
assert.strictEqual(test_string.TestPropertyKeyUtf16AutoLength(str1), str1);
assert.strictEqual(test_string.Utf16Length(str1), 11);
assert.strictEqual(test_string.Utf8Length(str1), 11);

Expand All @@ -50,6 +54,8 @@ assert.strictEqual(test_string.TestUtf16ExternalAutoLength(str2), str2);
assert.strictEqual(test_string.TestLatin1Insufficient(str2), str2.slice(0, 3));
assert.strictEqual(test_string.TestUtf8Insufficient(str2), str2.slice(0, 3));
assert.strictEqual(test_string.TestUtf16Insufficient(str2), str2.slice(0, 3));
assert.strictEqual(test_string.TestPropertyKeyUtf16(str2), str2);
assert.strictEqual(test_string.TestPropertyKeyUtf16AutoLength(str2), str2);
assert.strictEqual(test_string.Utf16Length(str2), 62);
assert.strictEqual(test_string.Utf8Length(str2), 62);

Expand All @@ -67,6 +73,8 @@ assert.strictEqual(test_string.TestUtf16ExternalAutoLength(str3), str3);
assert.strictEqual(test_string.TestLatin1Insufficient(str3), str3.slice(0, 3));
assert.strictEqual(test_string.TestUtf8Insufficient(str3), str3.slice(0, 3));
assert.strictEqual(test_string.TestUtf16Insufficient(str3), str3.slice(0, 3));
assert.strictEqual(test_string.TestPropertyKeyUtf16(str3), str3);
assert.strictEqual(test_string.TestPropertyKeyUtf16AutoLength(str3), str3);
assert.strictEqual(test_string.Utf16Length(str3), 27);
assert.strictEqual(test_string.Utf8Length(str3), 27);

Expand All @@ -84,6 +92,8 @@ assert.strictEqual(test_string.TestUtf16ExternalAutoLength(str4), str4);
assert.strictEqual(test_string.TestLatin1Insufficient(str4), str4.slice(0, 3));
assert.strictEqual(test_string.TestUtf8Insufficient(str4), str4.slice(0, 1));
assert.strictEqual(test_string.TestUtf16Insufficient(str4), str4.slice(0, 3));
assert.strictEqual(test_string.TestPropertyKeyUtf16(str4), str4);
assert.strictEqual(test_string.TestPropertyKeyUtf16AutoLength(str4), str4);
assert.strictEqual(test_string.Utf16Length(str4), 31);
assert.strictEqual(test_string.Utf8Length(str4), 62);

Expand All @@ -101,6 +111,8 @@ assert.strictEqual(test_string.TestUtf16ExternalAutoLength(str5), str5);
assert.strictEqual(test_string.TestLatin1Insufficient(str5), str5.slice(0, 3));
assert.strictEqual(test_string.TestUtf8Insufficient(str5), str5.slice(0, 1));
assert.strictEqual(test_string.TestUtf16Insufficient(str5), str5.slice(0, 3));
assert.strictEqual(test_string.TestPropertyKeyUtf16(str5), str5);
assert.strictEqual(test_string.TestPropertyKeyUtf16AutoLength(str5), str5);
assert.strictEqual(test_string.Utf16Length(str5), 63);
assert.strictEqual(test_string.Utf8Length(str5), 126);

Expand All @@ -113,6 +125,8 @@ assert.strictEqual(test_string.TestUtf16External(str6), str6);
assert.strictEqual(test_string.TestUtf16ExternalAutoLength(str6), str6);
assert.strictEqual(test_string.TestUtf8Insufficient(str6), str6.slice(0, 1));
assert.strictEqual(test_string.TestUtf16Insufficient(str6), str6.slice(0, 3));
assert.strictEqual(test_string.TestPropertyKeyUtf16(str6), str6);
assert.strictEqual(test_string.TestPropertyKeyUtf16AutoLength(str6), str6);
assert.strictEqual(test_string.Utf16Length(str6), 5);
assert.strictEqual(test_string.Utf8Length(str6), 14);

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20 changes: 20 additions & 0 deletions test/js-native-api/test_string/test_string.c
Original file line number Diff line number Diff line change
Expand Up @@ -294,6 +294,23 @@ static napi_value TestUtf16Insufficient(napi_env env, napi_callback_info info) {
return output;
}

static napi_value TestPropertyKeyUtf16(napi_env env, napi_callback_info info) {
return TestTwoByteImpl(env,
info,
napi_get_value_string_utf16,
node_api_create_property_key_utf16,
actual_length);
}

static napi_value TestPropertyKeyUtf16AutoLength(napi_env env,
napi_callback_info info) {
return TestTwoByteImpl(env,
info,
napi_get_value_string_utf16,
node_api_create_property_key_utf16,
auto_length);
}

static napi_value Utf16Length(napi_env env, napi_callback_info info) {
napi_value args[1];
NODE_API_CALL(env, validate_and_retrieve_single_string_arg(env, info, args));
Expand Down Expand Up @@ -410,6 +427,9 @@ napi_value Init(napi_env env, napi_value exports) {
DECLARE_NODE_API_PROPERTY("TestLargeLatin1", TestLargeLatin1),
DECLARE_NODE_API_PROPERTY("TestLargeUtf16", TestLargeUtf16),
DECLARE_NODE_API_PROPERTY("TestMemoryCorruption", TestMemoryCorruption),
DECLARE_NODE_API_PROPERTY("TestPropertyKeyUtf16", TestPropertyKeyUtf16),
DECLARE_NODE_API_PROPERTY("TestPropertyKeyUtf16AutoLength",
TestPropertyKeyUtf16AutoLength),
};

init_test_null(env, exports);
Expand Down

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