tidb column_filter 代码
文件路径：/util/table-filter/column_filter.go
/ Copyright 2022 PingCAP, 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 filter
import "strings"
/ ColumnFilter is a structure to check if a column should be included for processing.
type ColumnFilter interface {
/ MatchColumn checks if a column can be processed after applying the columnFilter.
MatchColumn(column string) bool
}
/ columnFilter is a concrete implementation of ColumnFilter.
type columnFilter []columnRule
/ ParseColumnFilter a columnFilter from a list of serialized columnFilter rules.
/ Column is not case-sensitive on any platform, nor are column aliases.
/ So the parsed columnFilter is case-insensitive.
func ParseColumnFilter(args []string) (ColumnFilter, error) {
p := columnRulesParser{
make([]columnRule, 0, len(args)),
matcherParser{
fileName: "<cmdline>",
lineNum: 1,
},
}
for _, arg := range args {
if err := p.parse(arg, true); err != nil {
return nil, err
}
}
reverse(p.rules)
return columnFilter(p.rules), nil
}
/ MatchColumn checks if a column can be processed after applying the columnFilter `f`.
/ Column is not case-sensitive on any platform, nor are column aliases.
/ So we always match in lowercase.
/ See also: https://dev.mysql.com/doc/refman/5.7/en/identifier-case-sensitivity.html
func (f columnFilter) MatchColumn(column string) bool {
lowercaseColumn := strings.ToLower(column)
for _, rule := range f {
if rule.column.matchString(lowercaseColumn) {
return rule.positive
}
}
return false
}