forked from dolthub/go-mysql-server
/
apply_hash_in.go
79 lines (73 loc) · 2.5 KB
/
apply_hash_in.go
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// Copyright 2021 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 analyzer
import (
"github.com/gabereiser/go-mysql-server/sql"
"github.com/gabereiser/go-mysql-server/sql/expression"
"github.com/gabereiser/go-mysql-server/sql/plan"
"github.com/gabereiser/go-mysql-server/sql/transform"
)
func applyHashIn(ctx *sql.Context, a *Analyzer, n sql.Node, scope *Scope, sel RuleSelector) (sql.Node, transform.TreeIdentity, error) {
return transform.Node(n, func(node sql.Node) (sql.Node, transform.TreeIdentity, error) {
filter, ok := node.(*plan.Filter)
if !ok {
return node, transform.SameTree, nil
}
e, same, err := transform.Expr(filter.Expression, func(expr sql.Expression) (sql.Expression, transform.TreeIdentity, error) {
if e, ok := expr.(*expression.InTuple); ok &&
hasSingleOutput(e.Left()) &&
isStatic(e.Right()) {
newe, err := expression.NewHashInTuple(ctx, e.Left(), e.Right())
if err != nil {
return nil, transform.SameTree, err
}
return newe, transform.NewTree, nil
}
return expr, transform.SameTree, nil
})
if err != nil {
return nil, transform.SameTree, err
}
if same {
return node, transform.SameTree, nil
}
node, err = filter.WithExpressions(e)
return node, transform.NewTree, err
})
}
// hasSingleOutput checks if an expression evaluates to a single output
func hasSingleOutput(e sql.Expression) bool {
return !transform.InspectExpr(e, func(expr sql.Expression) bool {
switch expr.(type) {
case expression.Tuple, *expression.Literal, *expression.GetField,
expression.Comparer, *expression.Convert, sql.FunctionExpression,
*expression.IsTrue, *expression.IsNull, expression.ArithmeticOp:
return false
default:
return true
}
return false
})
}
// isStatic checks if an expression is static
func isStatic(e sql.Expression) bool {
return !transform.InspectExpr(e, func(expr sql.Expression) bool {
switch expr.(type) {
case expression.Tuple, *expression.Literal:
return false
default:
return true
}
})
}