forked from TrueCloudLab/restic
101 lines
3.1 KiB
Go
101 lines
3.1 KiB
Go
/*
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Copyright 2017 Google Inc. All Rights Reserved.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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*/
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package spanner
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import (
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"errors"
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"fmt"
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proto3 "github.com/golang/protobuf/ptypes/struct"
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sppb "google.golang.org/genproto/googleapis/spanner/v1"
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"google.golang.org/grpc/codes"
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)
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// A Statement is a SQL query with named parameters.
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//
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// A parameter placeholder consists of '@' followed by the parameter name.
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// Parameter names consist of any combination of letters, numbers, and
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// underscores. Names may be entirely numeric (e.g., "WHERE m.id = @5").
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// Parameters may appear anywhere that a literal value is expected. The same
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// parameter name may be used more than once. It is an error to execute a
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// statement with unbound parameters. On the other hand, it is allowable to
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// bind parameter names that are not used.
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//
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// See the documentation of the Row type for how Go types are mapped to Cloud
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// Spanner types.
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type Statement struct {
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SQL string
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Params map[string]interface{}
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}
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// NewStatement returns a Statement with the given SQL and an empty Params map.
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func NewStatement(sql string) Statement {
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return Statement{SQL: sql, Params: map[string]interface{}{}}
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}
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// errBindParam returns error for not being able to bind parameter to query request.
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func errBindParam(k string, v interface{}, err error) error {
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if err == nil {
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return nil
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}
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se, ok := toSpannerError(err).(*Error)
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if !ok {
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return spannerErrorf(codes.InvalidArgument, "failed to bind query parameter(name: %q, value: %v), error = <%v>", k, v, err)
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}
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se.decorate(fmt.Sprintf("failed to bind query parameter(name: %q, value: %v)", k, v))
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return se
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}
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var (
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errNilParam = errors.New("use T(nil), not nil")
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errNoType = errors.New("no type information")
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)
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// bindParams binds parameters in a Statement to a sppb.ExecuteSqlRequest or sppb.PartitionQueryRequest.
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func (s *Statement) bindParams(i interface{}) error {
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params := &proto3.Struct{
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Fields: map[string]*proto3.Value{},
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}
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paramTypes := map[string]*sppb.Type{}
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for k, v := range s.Params {
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if v == nil {
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return errBindParam(k, v, errNilParam)
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}
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val, t, err := encodeValue(v)
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if err != nil {
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return errBindParam(k, v, err)
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}
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if t == nil { // should not happen, because of nil check above
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return errBindParam(k, v, errNoType)
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}
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params.Fields[k] = val
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paramTypes[k] = t
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}
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switch r := i.(type) {
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default:
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return fmt.Errorf("failed to bind query parameter, unexpected request type: %v", r)
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case *sppb.ExecuteSqlRequest:
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r.Params = params
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r.ParamTypes = paramTypes
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case *sppb.PartitionQueryRequest:
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r.Params = params
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r.ParamTypes = paramTypes
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}
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return nil
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}
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