github.com/dolthub/go-mysql-server@v0.18.0/sql/plan/set.go (about)

     1  // Copyright 2020-2021 Dolthub, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package plan
    16  
    17  import (
    18  	"fmt"
    19  	"strings"
    20  
    21  	"github.com/dolthub/go-mysql-server/sql"
    22  )
    23  
    24  // Set represents a set statement. This can be variables, but in some instances can also refer to row values.
    25  type Set struct {
    26  	Exprs []sql.Expression
    27  }
    28  
    29  var _ sql.Node = (*Set)(nil)
    30  var _ sql.CollationCoercible = (*Set)(nil)
    31  
    32  // NewSet creates a new Set node.
    33  func NewSet(vars []sql.Expression) *Set {
    34  	return &Set{Exprs: vars}
    35  }
    36  
    37  // Resolved implements the sql.Node interface.
    38  func (s *Set) Resolved() bool {
    39  	for _, v := range s.Exprs {
    40  		if !v.Resolved() {
    41  			return false
    42  		}
    43  	}
    44  	return true
    45  }
    46  
    47  // Children implements the sql.Node interface.
    48  func (s *Set) Children() []sql.Node { return nil }
    49  
    50  func (s *Set) IsReadOnly() bool { return true }
    51  
    52  // WithChildren implements the sql.Node interface.
    53  func (s *Set) WithChildren(children ...sql.Node) (sql.Node, error) {
    54  	if len(children) != 0 {
    55  		return nil, sql.ErrInvalidChildrenNumber.New(s, len(children), 0)
    56  	}
    57  
    58  	return s, nil
    59  }
    60  
    61  // CheckPrivileges implements the interface sql.Node.
    62  func (s *Set) CheckPrivileges(ctx *sql.Context, opChecker sql.PrivilegedOperationChecker) bool {
    63  	//TODO: determine which variables cannot be set without a privilege check
    64  	return true
    65  }
    66  
    67  // CollationCoercibility implements the interface sql.CollationCoercible.
    68  func (*Set) CollationCoercibility(ctx *sql.Context) (collation sql.CollationID, coercibility byte) {
    69  	return sql.Collation_binary, 7
    70  }
    71  
    72  // WithExpressions implements the sql.Expressioner interface.
    73  func (s *Set) WithExpressions(exprs ...sql.Expression) (sql.Node, error) {
    74  	if len(exprs) != len(s.Exprs) {
    75  		return nil, sql.ErrInvalidChildrenNumber.New(s, len(exprs), len(s.Exprs))
    76  	}
    77  
    78  	return NewSet(exprs), nil
    79  }
    80  
    81  // Expressions implements the sql.Expressioner interface.
    82  func (s *Set) Expressions() []sql.Expression {
    83  	return s.Exprs
    84  }
    85  
    86  // Schema implements the sql.Node interface.
    87  func (s *Set) Schema() sql.Schema {
    88  	return nil
    89  }
    90  
    91  func (s *Set) String() string {
    92  	var children = make([]string, len(s.Exprs))
    93  	for i, v := range s.Exprs {
    94  		children[i] = fmt.Sprintf(v.String())
    95  	}
    96  	return strings.Join(children, ", ")
    97  }
    98  
    99  func (s *Set) DebugString() string {
   100  	var children = make([]string, len(s.Exprs))
   101  	for i, v := range s.Exprs {
   102  		children[i] = fmt.Sprintf(sql.DebugString(v))
   103  	}
   104  	return strings.Join(children, ", ")
   105  }