276 lines
7.4 KiB
Go
276 lines
7.4 KiB
Go
// Copyright 2017 Google Inc. All Rights Reserved.
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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 firestore
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import (
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"bytes"
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"errors"
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"fmt"
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"reflect"
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"regexp"
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"sort"
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"strings"
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"cloud.google.com/go/internal/atomiccache"
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"cloud.google.com/go/internal/fields"
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pb "google.golang.org/genproto/googleapis/firestore/v1beta1"
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)
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// A FieldPath is a non-empty sequence of non-empty fields that reference a value.
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//
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// A FieldPath value should only be necessary if one of the field names contains
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// one of the runes ".˜*/[]". Most methods accept a simpler form of field path
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// as a string in which the individual fields are separated by dots.
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// For example,
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// []string{"a", "b"}
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// is equivalent to the string form
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// "a.b"
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// but
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// []string{"*"}
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// has no equivalent string form.
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type FieldPath []string
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// parseDotSeparatedString constructs a FieldPath from a string that separates
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// path components with dots. Other than splitting at dots and checking for invalid
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// characters, it ignores everything else about the string,
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// including attempts to quote field path compontents. So "a.`b.c`.d" is parsed into
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// four parts, "a", "`b", "c`" and "d".
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func parseDotSeparatedString(s string) (FieldPath, error) {
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const invalidRunes = "~*/[]"
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if strings.ContainsAny(s, invalidRunes) {
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return nil, fmt.Errorf("firestore: %q contains an invalid rune (one of %s)", s, invalidRunes)
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}
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fp := FieldPath(strings.Split(s, "."))
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if err := fp.validate(); err != nil {
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return nil, err
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}
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return fp, nil
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}
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func (fp1 FieldPath) equal(fp2 FieldPath) bool {
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if len(fp1) != len(fp2) {
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return false
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}
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for i, c1 := range fp1 {
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if c1 != fp2[i] {
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return false
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}
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}
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return true
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}
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func (fp1 FieldPath) prefixOf(fp2 FieldPath) bool {
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return len(fp1) <= len(fp2) && fp1.equal(fp2[:len(fp1)])
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}
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// Lexicographic ordering.
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func (fp1 FieldPath) less(fp2 FieldPath) bool {
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for i := range fp1 {
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switch {
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case i >= len(fp2):
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return false
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case fp1[i] < fp2[i]:
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return true
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case fp1[i] > fp2[i]:
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return false
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}
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}
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// fp1 and fp2 are equal up to len(fp1).
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return len(fp1) < len(fp2)
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}
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// validate checks the validity of fp and returns an error if it is invalid.
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func (fp FieldPath) validate() error {
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if len(fp) == 0 {
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return errors.New("firestore: empty field path")
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}
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for _, c := range fp {
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if len(c) == 0 {
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return errors.New("firestore: empty component in field path")
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}
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}
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return nil
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}
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// with creates a new FieldPath consisting of fp followed by k.
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func (fp FieldPath) with(k string) FieldPath {
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r := make(FieldPath, len(fp), len(fp)+1)
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copy(r, fp)
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return append(r, k)
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}
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// concat creates a new FieldPath consisting of fp1 followed by fp2.
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func (fp1 FieldPath) concat(fp2 FieldPath) FieldPath {
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r := make(FieldPath, len(fp1)+len(fp2))
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copy(r, fp1)
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copy(r[len(fp1):], fp2)
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return r
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}
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// in reports whether fp is equal to one of the fps.
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func (fp FieldPath) in(fps []FieldPath) bool {
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for _, e := range fps {
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if fp.equal(e) {
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return true
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}
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}
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return false
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}
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// checkNoDupOrPrefix checks whether any FieldPath is a prefix of (or equal to)
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// another.
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// It modifies the order of FieldPaths in its argument (via sorting).
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func checkNoDupOrPrefix(fps []FieldPath) error {
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// Sort fps lexicographically.
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sort.Sort(byPath(fps))
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// Check adjacent pairs for prefix.
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for i := 1; i < len(fps); i++ {
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if fps[i-1].prefixOf(fps[i]) {
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return fmt.Errorf("field path %v cannot be used in the same update as %v", fps[i-1], fps[i])
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}
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}
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return nil
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}
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type byPath []FieldPath
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func (b byPath) Len() int { return len(b) }
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func (b byPath) Swap(i, j int) { b[i], b[j] = b[j], b[i] }
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func (b byPath) Less(i, j int) bool { return b[i].less(b[j]) }
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// setAtPath sets val at the location in m specified by fp, creating sub-maps as
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// needed. m must not be nil. fp is assumed to be valid.
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func setAtPath(m map[string]*pb.Value, fp FieldPath, val *pb.Value) {
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if val == nil {
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return
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}
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if len(fp) == 1 {
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m[fp[0]] = val
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} else {
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v, ok := m[fp[0]]
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if !ok {
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v = &pb.Value{&pb.Value_MapValue{&pb.MapValue{map[string]*pb.Value{}}}}
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m[fp[0]] = v
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}
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// The type assertion below cannot fail, because setAtPath is only called
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// with either an empty map or one filled by setAtPath itself, and the
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// set of FieldPaths it is called with has been checked to make sure that
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// no path is the prefix of any other.
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setAtPath(v.GetMapValue().Fields, fp[1:], val)
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}
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}
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// getAtPath gets the value in data referred to by fp. The data argument can
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// be a map or a struct.
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// Compare with valueAtPath, which does the same thing for a document.
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func getAtPath(v reflect.Value, fp FieldPath) (interface{}, error) {
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var err error
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for _, k := range fp {
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v, err = getAtField(v, k)
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if err != nil {
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return nil, err
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}
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}
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return v.Interface(), nil
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}
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// getAtField returns the equivalent of v[k], if v is a map, or v.k if v is a struct.
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func getAtField(v reflect.Value, k string) (reflect.Value, error) {
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switch v.Kind() {
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case reflect.Map:
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if r := v.MapIndex(reflect.ValueOf(k)); r.IsValid() {
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return r, nil
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}
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case reflect.Struct:
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fm, err := fieldMap(v.Type())
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if err != nil {
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return reflect.Value{}, err
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}
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if f, ok := fm[k]; ok {
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return v.FieldByIndex(f.Index), nil
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}
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case reflect.Interface:
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return getAtField(v.Elem(), k)
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case reflect.Ptr:
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return getAtField(v.Elem(), k)
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}
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return reflect.Value{}, fmt.Errorf("firestore: no field %q for value %#v", k, v)
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}
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// fieldMapCache holds maps from from Firestore field name to struct field,
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// keyed by struct type.
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// TODO(jba): replace with sync.Map for Go 1.9.
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var fieldMapCache atomiccache.Cache
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func fieldMap(t reflect.Type) (map[string]fields.Field, error) {
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x := fieldMapCache.Get(t, func() interface{} {
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fieldList, err := fieldCache.Fields(t)
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if err != nil {
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return err
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}
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m := map[string]fields.Field{}
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for _, f := range fieldList {
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m[f.Name] = f
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}
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return m
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})
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if err, ok := x.(error); ok {
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return nil, err
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}
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return x.(map[string]fields.Field), nil
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}
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// toServiceFieldPath converts fp the form required by the Firestore service.
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// It assumes fp has been validated.
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func (fp FieldPath) toServiceFieldPath() string {
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cs := make([]string, len(fp))
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for i, c := range fp {
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cs[i] = toServiceFieldPathComponent(c)
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}
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return strings.Join(cs, ".")
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}
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func toServiceFieldPaths(fps []FieldPath) []string {
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var sfps []string
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for _, fp := range fps {
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sfps = append(sfps, fp.toServiceFieldPath())
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}
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return sfps
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}
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// Google SQL syntax for an unquoted field.
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var unquotedFieldRegexp = regexp.MustCompile("^[A-Za-z_][A-Za-z_0-9]*$")
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// toServiceFieldPathComponent returns a string that represents key and is a valid
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// field path component.
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func toServiceFieldPathComponent(key string) string {
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if unquotedFieldRegexp.MatchString(key) {
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return key
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}
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var buf bytes.Buffer
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buf.WriteRune('`')
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for _, r := range key {
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if r == '`' || r == '\\' {
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buf.WriteRune('\\')
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}
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buf.WriteRune(r)
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}
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buf.WriteRune('`')
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return buf.String()
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}
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