github.com/vedadiyan/sqlparser@v1.0.0/pkg/sqlparser/bind_var_needs.go (about)

     1  /*
     2  Copyright 2020 The Vitess Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package sqlparser
    18  
    19  // BindVarNeeds represents the bind vars that need to be provided as the result of expression rewriting.
    20  type BindVarNeeds struct {
    21  	NeedFunctionResult,
    22  	NeedSystemVariable,
    23  	// NeedUserDefinedVariables keeps track of all user defined variables a query is using
    24  	NeedUserDefinedVariables []string
    25  	otherRewrites bool
    26  }
    27  
    28  // MergeWith adds bind vars needs coming from sub scopes
    29  func (bvn *BindVarNeeds) MergeWith(other *BindVarNeeds) {
    30  	bvn.NeedFunctionResult = append(bvn.NeedFunctionResult, other.NeedFunctionResult...)
    31  	bvn.NeedSystemVariable = append(bvn.NeedSystemVariable, other.NeedSystemVariable...)
    32  	bvn.NeedUserDefinedVariables = append(bvn.NeedUserDefinedVariables, other.NeedUserDefinedVariables...)
    33  }
    34  
    35  // AddFuncResult adds a function bindvar need
    36  func (bvn *BindVarNeeds) AddFuncResult(name string) {
    37  	bvn.NeedFunctionResult = append(bvn.NeedFunctionResult, name)
    38  }
    39  
    40  // AddSysVar adds a system variable bindvar need
    41  func (bvn *BindVarNeeds) AddSysVar(name string) {
    42  	bvn.NeedSystemVariable = append(bvn.NeedSystemVariable, name)
    43  }
    44  
    45  // AddUserDefVar adds a user defined variable bindvar need
    46  func (bvn *BindVarNeeds) AddUserDefVar(name string) {
    47  	bvn.NeedUserDefinedVariables = append(bvn.NeedUserDefinedVariables, name)
    48  }
    49  
    50  // NeedsFuncResult says if a function result needs to be provided
    51  func (bvn *BindVarNeeds) NeedsFuncResult(name string) bool {
    52  	return contains(bvn.NeedFunctionResult, name)
    53  }
    54  
    55  // NeedsSysVar says if a function result needs to be provided
    56  func (bvn *BindVarNeeds) NeedsSysVar(name string) bool {
    57  	return contains(bvn.NeedSystemVariable, name)
    58  }
    59  
    60  func (bvn *BindVarNeeds) NoteRewrite() {
    61  	bvn.otherRewrites = true
    62  }
    63  
    64  func (bvn *BindVarNeeds) HasRewrites() bool {
    65  	return bvn.otherRewrites ||
    66  		len(bvn.NeedFunctionResult) > 0 ||
    67  		len(bvn.NeedUserDefinedVariables) > 0 ||
    68  		len(bvn.NeedSystemVariable) > 0
    69  }
    70  
    71  func contains(strings []string, name string) bool {
    72  	for _, s := range strings {
    73  		if name == s {
    74  			return true
    75  		}
    76  	}
    77  	return false
    78  }