/
helpers.go
74 lines (59 loc) · 1.82 KB
/
helpers.go
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// Copyright 2021 FerretDB 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 mysql
import (
"encoding/json"
"errors"
"fmt"
"golang.org/x/exp/maps"
"github.com/FerretDB/FerretDB/internal/types"
"github.com/FerretDB/FerretDB/internal/util/lazyerrors"
)
// unmarshalExplain unmarshalls the plan from EXPLAIN MySQL command.
// EXPLAIN result is not sjson, so it cannot be unmarshaled by sjson.Unmarshal.
func unmarshalExplain(b []byte) (*types.Document, error) {
var plans map[string]any
if err := json.Unmarshal(b, &plans); err != nil {
return nil, lazyerrors.Error(err)
}
if len(plans) == 0 {
return nil, lazyerrors.Error(errors.New("no execution plan returned"))
}
return convertJSON(plans).(*types.Document), nil
}
// convertJSON transforms decoded JSON map[string]any value into *types.Document.
func convertJSON(value any) any {
switch value := value.(type) {
case map[string]any:
d := types.MakeDocument(len(value))
keys := maps.Keys(value)
for _, k := range keys {
v := value[k]
d.Set(k, convertJSON(v))
}
return d
case []any:
a := types.MakeArray(len(value))
for _, v := range value {
a.Append(convertJSON(v))
}
return a
case nil:
return types.Null
case float64, string, bool:
return value
default:
panic(fmt.Sprintf("unsupported type: %[1]v (%[1]v)", value))
}
}