Vendor dependencies for GCS

vendor/cloud.google.com/go/bigquery/schema.go

@@ -0,0 +1,315 @@
+// Copyright 2015 Google Inc. All Rights Reserved.
+//
+// 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 bigquery
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+
+	"cloud.google.com/go/internal/atomiccache"
+
+	bq "google.golang.org/api/bigquery/v2"
+)
+
+// Schema describes the fields in a table or query result.
+type Schema []*FieldSchema
+
+type FieldSchema struct {
+	// The field name.
+	// Must contain only letters (a-z, A-Z), numbers (0-9), or underscores (_),
+	// and must start with a letter or underscore.
+	// The maximum length is 128 characters.
+	Name string
+
+	// A description of the field. The maximum length is 16,384 characters.
+	Description string
+
+	// Whether the field may contain multiple values.
+	Repeated bool
+	// Whether the field is required.  Ignored if Repeated is true.
+	Required bool
+
+	// The field data type.  If Type is Record, then this field contains a nested schema,
+	// which is described by Schema.
+	Type FieldType
+	// Describes the nested schema if Type is set to Record.
+	Schema Schema
+}
+
+func (fs *FieldSchema) asTableFieldSchema() *bq.TableFieldSchema {
+	tfs := &bq.TableFieldSchema{
+		Description: fs.Description,
+		Name:        fs.Name,
+		Type:        string(fs.Type),
+	}
+
+	if fs.Repeated {
+		tfs.Mode = "REPEATED"
+	} else if fs.Required {
+		tfs.Mode = "REQUIRED"
+	} // else leave as default, which is interpreted as NULLABLE.
+
+	for _, f := range fs.Schema {
+		tfs.Fields = append(tfs.Fields, f.asTableFieldSchema())
+	}
+
+	return tfs
+}
+
+func (s Schema) asTableSchema() *bq.TableSchema {
+	var fields []*bq.TableFieldSchema
+	for _, f := range s {
+		fields = append(fields, f.asTableFieldSchema())
+	}
+	return &bq.TableSchema{Fields: fields}
+}
+
+// customizeCreateTable allows a Schema to be used directly as an option to CreateTable.
+func (s Schema) customizeCreateTable(conf *createTableConf) {
+	conf.schema = s.asTableSchema()
+}
+
+func convertTableFieldSchema(tfs *bq.TableFieldSchema) *FieldSchema {
+	fs := &FieldSchema{
+		Description: tfs.Description,
+		Name:        tfs.Name,
+		Repeated:    tfs.Mode == "REPEATED",
+		Required:    tfs.Mode == "REQUIRED",
+		Type:        FieldType(tfs.Type),
+	}
+
+	for _, f := range tfs.Fields {
+		fs.Schema = append(fs.Schema, convertTableFieldSchema(f))
+	}
+	return fs
+}
+
+func convertTableSchema(ts *bq.TableSchema) Schema {
+	if ts == nil {
+		return nil
+	}
+	var s Schema
+	for _, f := range ts.Fields {
+		s = append(s, convertTableFieldSchema(f))
+	}
+	return s
+}
+
+type FieldType string
+
+const (
+	StringFieldType    FieldType = "STRING"
+	BytesFieldType     FieldType = "BYTES"
+	IntegerFieldType   FieldType = "INTEGER"
+	FloatFieldType     FieldType = "FLOAT"
+	BooleanFieldType   FieldType = "BOOLEAN"
+	TimestampFieldType FieldType = "TIMESTAMP"
+	RecordFieldType    FieldType = "RECORD"
+	DateFieldType      FieldType = "DATE"
+	TimeFieldType      FieldType = "TIME"
+	DateTimeFieldType  FieldType = "DATETIME"
+)
+
+var (
+	errNoStruct             = errors.New("bigquery: can only infer schema from struct or pointer to struct")
+	errUnsupportedFieldType = errors.New("bigquery: unsupported type of field in struct")
+	errInvalidFieldName     = errors.New("bigquery: invalid name of field in struct")
+)
+
+var typeOfByteSlice = reflect.TypeOf([]byte{})
+
+// InferSchema tries to derive a BigQuery schema from the supplied struct value.
+// NOTE: All fields in the returned Schema are configured to be required,
+// unless the corresponding field in the supplied struct is a slice or array.
+//
+// It is considered an error if the struct (including nested structs) contains
+// any exported fields that are pointers or one of the following types:
+// uint, uint64, uintptr, map, interface, complex64, complex128, func, chan.
+// In these cases, an error will be returned.
+// Future versions may handle these cases without error.
+//
+// Recursively defined structs are also disallowed.
+func InferSchema(st interface{}) (Schema, error) {
+	return inferSchemaReflectCached(reflect.TypeOf(st))
+}
+
+var schemaCache atomiccache.Cache
+
+type cacheVal struct {
+	schema Schema
+	err    error
+}
+
+func inferSchemaReflectCached(t reflect.Type) (Schema, error) {
+	cv := schemaCache.Get(t, func() interface{} {
+		s, err := inferSchemaReflect(t)
+		return cacheVal{s, err}
+	}).(cacheVal)
+	return cv.schema, cv.err
+}
+
+func inferSchemaReflect(t reflect.Type) (Schema, error) {
+	rec, err := hasRecursiveType(t, nil)
+	if err != nil {
+		return nil, err
+	}
+	if rec {
+		return nil, fmt.Errorf("bigquery: schema inference for recursive type %s", t)
+	}
+	return inferStruct(t)
+}
+
+func inferStruct(t reflect.Type) (Schema, error) {
+	switch t.Kind() {
+	case reflect.Ptr:
+		if t.Elem().Kind() != reflect.Struct {
+			return nil, errNoStruct
+		}
+		t = t.Elem()
+		fallthrough
+
+	case reflect.Struct:
+		return inferFields(t)
+	default:
+		return nil, errNoStruct
+	}
+}
+
+// inferFieldSchema infers the FieldSchema for a Go type
+func inferFieldSchema(rt reflect.Type) (*FieldSchema, error) {
+	switch rt {
+	case typeOfByteSlice:
+		return &FieldSchema{Required: true, Type: BytesFieldType}, nil
+	case typeOfGoTime:
+		return &FieldSchema{Required: true, Type: TimestampFieldType}, nil
+	case typeOfDate:
+		return &FieldSchema{Required: true, Type: DateFieldType}, nil
+	case typeOfTime:
+		return &FieldSchema{Required: true, Type: TimeFieldType}, nil
+	case typeOfDateTime:
+		return &FieldSchema{Required: true, Type: DateTimeFieldType}, nil
+	}
+	if isSupportedIntType(rt) {
+		return &FieldSchema{Required: true, Type: IntegerFieldType}, nil
+	}
+	switch rt.Kind() {
+	case reflect.Slice, reflect.Array:
+		et := rt.Elem()
+		if et != typeOfByteSlice && (et.Kind() == reflect.Slice || et.Kind() == reflect.Array) {
+			// Multi dimensional slices/arrays are not supported by BigQuery
+			return nil, errUnsupportedFieldType
+		}
+
+		f, err := inferFieldSchema(et)
+		if err != nil {
+			return nil, err
+		}
+		f.Repeated = true
+		f.Required = false
+		return f, nil
+	case reflect.Struct, reflect.Ptr:
+		nested, err := inferStruct(rt)
+		if err != nil {
+			return nil, err
+		}
+		return &FieldSchema{Required: true, Type: RecordFieldType, Schema: nested}, nil
+	case reflect.String:
+		return &FieldSchema{Required: true, Type: StringFieldType}, nil
+	case reflect.Bool:
+		return &FieldSchema{Required: true, Type: BooleanFieldType}, nil
+	case reflect.Float32, reflect.Float64:
+		return &FieldSchema{Required: true, Type: FloatFieldType}, nil
+	default:
+		return nil, errUnsupportedFieldType
+	}
+}
+
+// inferFields extracts all exported field types from struct type.
+func inferFields(rt reflect.Type) (Schema, error) {
+	var s Schema
+	fields, err := fieldCache.Fields(rt)
+	if err != nil {
+		return nil, err
+	}
+	for _, field := range fields {
+		f, err := inferFieldSchema(field.Type)
+		if err != nil {
+			return nil, err
+		}
+		f.Name = field.Name
+		s = append(s, f)
+	}
+	return s, nil
+}
+
+// isSupportedIntType reports whether t can be properly represented by the
+// BigQuery INTEGER/INT64 type.
+func isSupportedIntType(t reflect.Type) bool {
+	switch t.Kind() {
+	case reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Int,
+		reflect.Uint8, reflect.Uint16, reflect.Uint32:
+		return true
+	default:
+		return false
+	}
+}
+
+// typeList is a linked list of reflect.Types.
+type typeList struct {
+	t    reflect.Type
+	next *typeList
+}
+
+func (l *typeList) has(t reflect.Type) bool {
+	for l != nil {
+		if l.t == t {
+			return true
+		}
+		l = l.next
+	}
+	return false
+}
+
+// hasRecursiveType reports whether t or any type inside t refers to itself, directly or indirectly,
+// via exported fields. (Schema inference ignores unexported fields.)
+func hasRecursiveType(t reflect.Type, seen *typeList) (bool, error) {
+	for t.Kind() == reflect.Ptr || t.Kind() == reflect.Slice || t.Kind() == reflect.Array {
+		t = t.Elem()
+	}
+	if t.Kind() != reflect.Struct {
+		return false, nil
+	}
+	if seen.has(t) {
+		return true, nil
+	}
+	fields, err := fieldCache.Fields(t)
+	if err != nil {
+		return false, err
+	}
+	seen = &typeList{t, seen}
+	// Because seen is a linked list, additions to it from one field's
+	// recursive call will not affect the value for subsequent fields' calls.
+	for _, field := range fields {
+		ok, err := hasRecursiveType(field.Type, seen)
+		if err != nil {
+			return false, err
+		}
+		if ok {
+			return true, nil
+		}
+	}
+	return false, nil
+}