chore: import upstream snapshot with attribution

server/expression/unary_operator.go

@@ -0,0 +1,117 @@
+// Copyright 2024 Dolthub, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package expression
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/cockroachdb/errors"
+	"github.com/dolthub/go-mysql-server/sql"
+	vitess "github.com/dolthub/vitess/go/vt/sqlparser"
+
+	"github.com/dolthub/doltgresql/server/functions/framework"
+)
+
+// UnaryOperator represents a VALUE OPERATOR VALUE expression.
+type UnaryOperator struct {
+	operator     framework.Operator
+	compiledFunc framework.Function
+}
+
+var _ vitess.Injectable = (*UnaryOperator)(nil)
+var _ sql.Expression = (*UnaryOperator)(nil)
+
+// NewUnaryOperator returns a new *UnaryOperator.
+func NewUnaryOperator(operator framework.Operator) *UnaryOperator {
+	return &UnaryOperator{operator: operator}
+}
+
+// Children implements the sql.Expression interface.
+func (b *UnaryOperator) Children() []sql.Expression {
+	return b.compiledFunc.Children()
+}
+
+// Eval implements the sql.Expression interface.
+func (b *UnaryOperator) Eval(ctx *sql.Context, row sql.Row) (any, error) {
+	return b.compiledFunc.Eval(ctx, row)
+}
+
+// IsNullable implements the sql.Expression interface.
+func (b *UnaryOperator) IsNullable(ctx *sql.Context) bool {
+	return b.compiledFunc.IsNullable(ctx)
+}
+
+// Resolved implements the sql.Expression interface.
+func (b *UnaryOperator) Resolved() bool {
+	return b.compiledFunc.Resolved()
+}
+
+// String implements the sql.Expression interface.
+func (b *UnaryOperator) String() string {
+	if b.compiledFunc == nil {
+		return fmt.Sprintf("%s?", b.operator.String())
+	}
+	// We know that we'll always have one parameter here
+	switch f := b.compiledFunc.(type) {
+	case *framework.CompiledFunction:
+		return fmt.Sprintf("%s%s", b.operator.String(), f.Arguments[0].String())
+	case *framework.QuickFunction1:
+		return fmt.Sprintf("%s%s", b.operator.String(), f.Argument.String())
+	default:
+		return fmt.Sprintf("unexpected unary operator function type: %T", b.compiledFunc)
+	}
+}
+
+// Type implements the sql.Expression interface.
+func (b *UnaryOperator) Type(ctx *sql.Context) sql.Type {
+	return b.compiledFunc.Type(ctx)
+}
+
+// WithChildren implements the sql.Expression interface.
+func (b *UnaryOperator) WithChildren(ctx *sql.Context, children ...sql.Expression) (sql.Expression, error) {
+	if len(children) != 1 {
+		return nil, sql.ErrInvalidChildrenNumber.New(b, len(children), 1)
+	}
+	compiledFunc, err := b.compiledFunc.WithChildren(ctx, children...)
+	if err != nil {
+		return nil, err
+	}
+	return &UnaryOperator{
+		operator:     b.operator,
+		compiledFunc: compiledFunc.(framework.Function),
+	}, nil
+}
+
+// WithResolvedChildren implements the vitess.InjectableExpression interface.
+func (b *UnaryOperator) WithResolvedChildren(ctx context.Context, children []any) (any, error) {
+	if len(children) != 1 {
+		return nil, errors.Errorf("invalid vitess child count, expected `1` but got `%d`", len(children))
+	}
+	sqlCtx := ctx.(*sql.Context)
+	child, ok := children[0].(sql.Expression)
+	if !ok {
+		return nil, errors.Errorf("expected vitess child to be an expression but has type `%T`", children[0])
+	}
+	funcName := "internal_unary_operator_func_" + b.operator.String()
+	compiledFunc := framework.GetUnaryFunction(b.operator).Compile(sqlCtx, funcName, child)
+	if compiledFunc == nil {
+		return nil, errors.Errorf("operator does not exist: %s%s", b.operator.String(), child.Type(sqlCtx).String())
+	}
+	return &UnaryOperator{
+		operator:     b.operator,
+		compiledFunc: compiledFunc,
+	}, nil
+}