wehub-resource-sync
82 lines
2.4 KiB
Go
82 lines
2.4 KiB
Go
// Copyright 2019 Dolthub, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package rowconv
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import (
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"errors"
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"fmt"
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"github.com/dolthub/dolt/go/cmd/dolt/errhand"
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"github.com/dolthub/dolt/go/libraries/utils/filesys"
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)
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// ErrMappingFileRead is an error returned when a mapping file cannot be read
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var ErrMappingFileRead = errors.New("error reading mapping file")
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// BadMappingErr is a struct which implements the error interface and is used when there is an error with a mapping.
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type BadMappingErr struct {
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srcField string
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destField string
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}
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// String representing the BadMappingError
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func (err *BadMappingErr) Error() string {
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return fmt.Sprintf("Mapping file attempted to map %s to %s, but one or both of those fields are unknown.", err.srcField, err.destField)
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}
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// NameMapper is a simple interface for mapping a string to another string
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type NameMapper map[string]string
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// Map maps a string to another string. If a string is not in the mapping ok will be false, otherwise it is true.
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func (nm NameMapper) Map(str string) string {
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v, ok := nm[str]
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if ok {
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return v
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}
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return str
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}
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// PreImage searches the NameMapper for the string that maps to str, returns str otherwise
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func (nm NameMapper) PreImage(str string) string {
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for pre, post := range nm {
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if post == str {
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return pre
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}
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}
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return str
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}
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// NameMapperFromFile reads a JSON file containing a name mapping and returns a NameMapper.
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func NameMapperFromFile(mappingFile string, FS filesys.ReadableFS) (NameMapper, error) {
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var nm NameMapper
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if mappingFile == "" {
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// identity mapper
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return make(NameMapper), nil
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}
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if fileExists, _ := FS.Exists(mappingFile); !fileExists {
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return nil, errhand.BuildDError("error: '%s' does not exist.", mappingFile).Build()
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}
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err := filesys.UnmarshalJSONFile(FS, mappingFile, &nm)
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if err != nil {
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return nil, errhand.BuildDError("%s", ErrMappingFileRead.Error()).AddCause(err).Build()
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}
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return nm, nil
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}
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