/
if_else.go
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/
if_else.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 plan
import (
"fmt"
"github.com/dolthub/go-mysql-server/sql"
)
// IfConditional represents IF statements only.
type IfConditional struct {
Condition sql.Expression
Body sql.Node
}
var _ sql.Node = (*IfConditional)(nil)
var _ sql.DebugStringer = (*IfConditional)(nil)
var _ sql.Expressioner = (*IfConditional)(nil)
var _ sql.CollationCoercible = (*IfConditional)(nil)
var _ RepresentsBlock = (*IfConditional)(nil)
// NewIfConditional creates a new *IfConditional node.
func NewIfConditional(condition sql.Expression, body sql.Node) *IfConditional {
return &IfConditional{
Condition: condition,
Body: body,
}
}
func (ic *IfConditional) IsReadOnly() bool {
return ic.Body.IsReadOnly()
}
// Resolved implements the sql.Node interface.
func (ic *IfConditional) Resolved() bool {
return ic.Condition.Resolved() && ic.Body.Resolved()
}
// String implements the sql.Node interface.
func (ic *IfConditional) String() string {
p := sql.NewTreePrinter()
_ = p.WriteNode(fmt.Sprintf("IF(%s)", ic.Condition.String()))
_ = p.WriteChildren(ic.Body.String())
return p.String()
}
// DebugString implements the sql.DebugStringer interface.
func (ic *IfConditional) DebugString() string {
p := sql.NewTreePrinter()
_ = p.WriteNode(fmt.Sprintf("IF(%s)", sql.DebugString(ic.Condition)))
_ = p.WriteChildren(sql.DebugString(ic.Body))
return p.String()
}
// Schema implements the sql.Node interface.
func (ic *IfConditional) Schema() sql.Schema {
return ic.Body.Schema()
}
// Children implements the sql.Node interface.
func (ic *IfConditional) Children() []sql.Node {
return []sql.Node{ic.Body}
}
// WithChildren implements the sql.Node interface.
func (ic *IfConditional) WithChildren(children ...sql.Node) (sql.Node, error) {
if len(children) != 1 {
return nil, sql.ErrInvalidChildrenNumber.New(ic, len(children), 1)
}
nic := *ic
nic.Body = children[0]
return &nic, nil
}
// CheckPrivileges implements the interface sql.Node.
func (ic *IfConditional) CheckPrivileges(ctx *sql.Context, opChecker sql.PrivilegedOperationChecker) bool {
return ic.Body.CheckPrivileges(ctx, opChecker)
}
// CollationCoercibility implements the interface sql.CollationCoercible.
func (ic *IfConditional) CollationCoercibility(ctx *sql.Context) (collation sql.CollationID, coercibility byte) {
return sql.GetCoercibility(ctx, ic.Body)
}
// Expressions implements the sql.Expressioner interface.
func (ic *IfConditional) Expressions() []sql.Expression {
return []sql.Expression{ic.Condition}
}
// WithExpressions implements the sql.Expressioner interface.
func (ic *IfConditional) WithExpressions(exprs ...sql.Expression) (sql.Node, error) {
if len(exprs) != 1 {
return nil, sql.ErrInvalidChildrenNumber.New(ic, len(exprs), 1)
}
nic := *ic
nic.Condition = exprs[0]
return &nic, nil
}
// implementsRepresentsBlock implements the RepresentsBlock interface.
func (ic *IfConditional) implementsRepresentsBlock() {}
// IfElseBlock represents IF/ELSE IF/ELSE statements.
type IfElseBlock struct {
IfConditionals []*IfConditional
Else sql.Node
}
var _ sql.CollationCoercible = (*IfElseBlock)(nil)
var _ sql.DebugStringer = (*IfElseBlock)(nil)
var _ RepresentsBlock = (*IfElseBlock)(nil)
// NewIfElse creates a new *IfElseBlock node.
func NewIfElse(ifConditionals []*IfConditional, elseStatement sql.Node) *IfElseBlock {
return &IfElseBlock{
IfConditionals: ifConditionals,
Else: elseStatement,
}
}
// Resolved implements the sql.Node interface.
func (ieb *IfElseBlock) Resolved() bool {
for _, s := range ieb.IfConditionals {
if !s.Resolved() {
return false
}
}
return ieb.Else.Resolved()
}
func (ieb *IfElseBlock) IsReadOnly() bool {
for _, s := range ieb.IfConditionals {
if !s.IsReadOnly() {
return false
}
}
return ieb.Else.IsReadOnly()
}
// String implements the sql.Node interface.
func (ieb *IfElseBlock) String() string {
p := sql.NewTreePrinter()
_ = p.WriteNode("IF BLOCK")
var children []string
for _, s := range ieb.IfConditionals {
children = append(children, s.String())
}
_ = p.WriteChildren(children...)
ep := sql.NewTreePrinter()
_ = ep.WriteNode("ELSE")
_ = ep.WriteChildren(ieb.Else.String())
_ = p.WriteChildren(ep.String())
return p.String()
}
// DebugString implements the sql.DebugStringer interface.
func (ieb *IfElseBlock) DebugString() string {
p := sql.NewTreePrinter()
_ = p.WriteNode("IF BLOCK")
var children []string
for _, s := range ieb.IfConditionals {
children = append(children, sql.DebugString(s))
}
_ = p.WriteChildren(children...)
ep := sql.NewTreePrinter()
_ = ep.WriteNode("ELSE")
_ = ep.WriteChildren(sql.DebugString(ieb.Else))
_ = p.WriteChildren(ep.String())
return p.String()
}
// Schema implements the sql.Node interface.
func (ieb *IfElseBlock) Schema() sql.Schema {
// NOTE: nil schema causes no result for over the wire clients
return nil
}
// Children implements the sql.Node interface.
func (ieb *IfElseBlock) Children() []sql.Node {
statements := make([]sql.Node, len(ieb.IfConditionals)+1)
for i, ifConditional := range ieb.IfConditionals {
statements[i] = ifConditional
}
statements[len(ieb.IfConditionals)] = ieb.Else
return statements
}
// WithChildren implements the sql.Node interface.
func (ieb *IfElseBlock) WithChildren(children ...sql.Node) (sql.Node, error) {
if len(children) < 2 {
return nil, fmt.Errorf("%T: invalid children number, got %d, expected at least 2", ieb, len(children))
}
ifConditionals := make([]*IfConditional, len(children)-1)
for i, child := range children[:len(children)-1] {
ifConditional, ok := child.(*IfConditional)
if !ok {
return nil, fmt.Errorf("%T: expected if conditional child but got %T", ieb, child)
}
ifConditionals[i] = ifConditional
}
return NewIfElse(ifConditionals, children[len(children)-1]), nil
}
// CheckPrivileges implements the interface sql.Node.
func (ieb *IfElseBlock) CheckPrivileges(ctx *sql.Context, opChecker sql.PrivilegedOperationChecker) bool {
for _, ifBlock := range ieb.IfConditionals {
if !ifBlock.CheckPrivileges(ctx, opChecker) {
return false
}
}
if ieb.Else != nil {
return ieb.Else.CheckPrivileges(ctx, opChecker)
}
return true
}
// CollationCoercibility implements the interface sql.CollationCoercible.
func (ieb *IfElseBlock) CollationCoercibility(ctx *sql.Context) (collation sql.CollationID, coercibility byte) {
// We'll only be able to know which branch was taken during the RowIter, so we can't rely on that here.
// I'm going to make the assumption that this will never need to be used, so we'll return 7 here.
return sql.Collation_binary, 7
}
// implementsRepresentsBlock implements the RepresentsBlock interface.
func (ieb *IfElseBlock) implementsRepresentsBlock() {}