perf(spanner): single-pass protobuf value encoding in codec

handwritten/spanner/src/codec.ts

@@ -13,7 +13,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import {GrpcService} from './common-grpc/service';
 import {PreciseDate} from '@google-cloud/precise-date';
 import {
   isArray,
@@ -938,7 +937,7 @@
     return val => val;
   }
 
   let decoder: (val: any) => any;
 
   switch (type.code) {
     case spannerClient.spanner.v1.TypeCode.BYTES:
@@ -952,8 +951,8 @@
         decoder = val => {
           const decoded = Buffer.from(val, 'base64');
           if (columnMetadata) {
             return (columnMetadata as any)['toObject'](
               (columnMetadata as any)['decode'](decoded),
             );
           }
           return decoded.toString();
@@ -981,7 +980,7 @@
             columnMetadata &&
             Object.prototype.hasOwnProperty.call(columnMetadata, val)
           ) {
             enumVal = (columnMetadata as any)[val];
           } else {
             throw new GoogleError(
               'protoEnumParams cannot be used for constructing the ProtoEnum. Pass the number as the value or provide the enum string constant as the value along with the corresponding enumObject generated by protobufjs-cli.',
@@ -997,7 +996,7 @@
               return proto[enumVal];
             }
             if (Object.prototype.hasOwnProperty.call(columnMetadata, enumVal)) {
               return (columnMetadata as any)[enumVal];
             }
           }
           return enumVal;
@@ -1129,7 +1128,7 @@
               name !== null &&
               name !== undefined &&
               Object.prototype.hasOwnProperty.call(columnMetadata, name)
               ? (columnMetadata as any)[name]
               : undefined,
             options,
           ),
@@ -1299,79 +1298,150 @@
 /**
  * Encode a value in the format the API expects.
  *
+ * This emits the `google.protobuf.Value` shape in a single pass: values are
+ * normalized and wrapped in their protobuf kind at the same time, so neither an
+ * intermediate representation nor a per-value `ObjectToStructConverter` is
+ * allocated. The branches prioritize primitive and common types for fast
+ * dispatch in hot query execution paths.
+ *
  * @private
  *
  * @param {*} value The value to be encoded.
  * @returns {object} google.protobuf.Value
  */
 function encode(value: Value): p.IValue {
-  return GrpcService.encodeValue_(encodeValue(value));
+  switch (typeof value) {
+    case 'string':
+      return {stringValue: value};
+    case 'number':
+      // Only non-integer, finite numbers are sent as a protobuf number. Every
+      // other numeric value — integers (INT64 is a string on the wire) as well
+      // as NaN and ±Infinity — is sent as a string.
+      return Number.isFinite(value) && !Number.isInteger(value)
+        ? {numberValue: value}
+        : {stringValue: value.toString()};
+    case 'boolean':
+      return {boolValue: value};
+    case 'object':
+      return value === null ? {nullValue: 0} : encodeObject(value);
+    default:
+      throw new Error(`Value of type ${typeof value} not recognized.`);
+  }
 }
 
 /**
- * Formats values into expected format of google.protobuf.Value. The actual
- * conversion to a google.protobuf.Value object happens via
- * `Service.encodeValue_`
+ * Encodes a non-null object into a google.protobuf.Value.
  *
  * @private
  *
- * @param {*} value The value to be encoded.
- * @returns {*}
+ * @param {object} value The value to be encoded.
+ * @returns {object} google.protobuf.Value
  */
-function encodeValue(value: Value): Value {
-  if (isNumber(value) && !isDecimal(value)) {
-    return value.toString();
+function encodeObject(value: object): p.IValue {
+  if (value instanceof Date) {
+    // `Date.prototype.toJSON` returns null for invalid dates.
+    const json: string | null = value.toJSON();
+    return json === null ? {nullValue: 0} : {stringValue: json};
   }
 
-  if (isDate(value)) {
-    return value.toJSON();
+  if (value instanceof WrappedNumber) {
+    // `Float`/`Float32` hold a number, `Int`/`PGOid` hold a string.
+    return encodeNumberOrString(value.value);
   }
 
-  if (value instanceof WrappedNumber) {
-    return value.value;
+  if (Array.isArray(value)) {
+    return {listValue: {values: encodeArrayValues(value)}};
   }
 
-  if (value instanceof Numeric) {
-    return value.value;
+  if (Buffer.isBuffer(value)) {
+    return {stringValue: value.toString('base64')};
   }
 
-  if (value instanceof PGNumeric) {
-    return value.value;
+  if (value instanceof Numeric || value instanceof PGNumeric) {
+    return {stringValue: value.value};
   }
 
-  if (Buffer.isBuffer(value)) {
-    return value.toString('base64');
+  if (value instanceof Interval) {
+    return {stringValue: value.toISO8601()};
   }
 
   if (value instanceof ProtoMessage) {
-    return value.value.toString('base64');
+    return {stringValue: value.value.toString('base64')};
   }
 
   if (value instanceof ProtoEnum) {
-    return value.value;
+    // Holds either the numeric constant or its string representation.
+    return encodeNumberOrString(value.value);
   }
 
-  if (value instanceof Struct) {
-    return Array.from(value).map(field => encodeValue(field.value));
+  if (value instanceof PGJsonb) {
+    return {stringValue: value.toString()};
   }
 
-  if (isArray(value)) {
-    return value.map(encodeValue);
+  if (isObject(value)) {
+    const json = JSON.stringify(value);
+    // `JSON.stringify` returns undefined only when an object's `toJSON()`
+    // method returns undefined. Other objects without a JSON representation
+    // (such as Functions, Symbols, and Maps) fail `isObject` and throw below.
+    // Note: `JSON.stringify` will throw a TypeError for circular structures
+    // or BigInt property values.
+    if (json !== undefined) {
+      return {stringValue: json};
+    }
   }
 
-  if (value instanceof PGJsonb) {
-    return value.toString();
+  if (
+    value instanceof Number ||
+    value instanceof String ||
+    value instanceof Boolean
+  ) {
+    // Boxed primitives are never produced by the public API, but were accepted
+    // by the previous implementation.
+    return encode(value.valueOf());
   }
 
-  if (value instanceof Interval) {
-    return value.toISO8601();
+  if (isDate(value)) {
+    // A `Date` from another realm (e.g. a `vm` context) fails `instanceof`.
+    const json: string | null = (value as Date).toJSON();
+    return json === null ? {nullValue: 0} : {stringValue: json};
   }
 
-  if (isObject(value)) {
-    return JSON.stringify(value);
+  throw new Error('Value of type object not recognized.');
+}
+
+/**
+ * Encodes the members of an array — or the field values of a {@link Struct},
+ * which is itself an array — into google.protobuf.Value messages.
+ *
+ * @private
+ *
+ * @param {Array} value The array to be encoded.
+ * @returns {object[]} google.protobuf.Value[]
+ */
+function encodeArrayValues(value: Value[]): p.IValue[] {
+  const {length} = value;
+  const values: p.IValue[] = new Array(length);
+  const isStruct = value instanceof Struct;
+
+  for (let i = 0; i < length; i++) {
+    values[i] = encode(isStruct ? value[i].value : value[i]);
   }
 
-  return value;
+  return values;
+}
+
+/**
+ * Wraps an already normalized value in the matching google.protobuf.Value kind.
+ *
+ * @private
+ *
+ * @param {string|number} value The value to be wrapped.
+ * @returns {object} google.protobuf.Value
+ */
+function encodeNumberOrString(value: string | number): p.IValue {
+  return typeof value === 'number'
+    ? {numberValue: value}
+    : {stringValue: value};
 }
 
 /**