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// Copyright 2017 Google LLC
//
// 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 firestore
import (
"context"
"errors"
"fmt"
"io"
"math"
"reflect"
"time"
"cloud.google.com/go/internal/btree"
"github.com/golang/protobuf/ptypes/wrappers"
"google.golang.org/api/iterator"
pb "google.golang.org/genproto/googleapis/firestore/v1"
)
// Query represents a Firestore query.
//
// Query values are immutable. Each Query method creates
// a new Query; it does not modify the old.
type Query struct {
c *Client
path string // path to query (collection)
parentPath string // path of the collection's parent (document)
collectionID string
selection []FieldPath
filters []filter
orders []order
offset int32
limit *wrappers.Int32Value
startVals, endVals []interface{}
startDoc, endDoc *DocumentSnapshot
startBefore, endBefore bool
err error
}
// DocumentID is the special field name representing the ID of a document
// in queries.
const DocumentID = "__name__"
// Select returns a new Query that specifies the paths
// to return from the result documents.
// Each path argument can be a single field or a dot-separated sequence of
// fields, and must not contain any of the runes "˜*/[]".
//
// An empty Select call will produce a query that returns only document IDs.
func (q Query) Select(paths ...string) Query {
var fps []FieldPath
for _, s := range paths {
fp, err := parseDotSeparatedString(s)
if err != nil {
q.err = err
return q
}
fps = append(fps, fp)
}
return q.SelectPaths(fps...)
}
// SelectPaths returns a new Query that specifies the field paths
// to return from the result documents.
//
// An empty SelectPaths call will produce a query that returns only document IDs.
func (q Query) SelectPaths(fieldPaths ...FieldPath) Query {
if len(fieldPaths) == 0 {
q.selection = []FieldPath{{DocumentID}}
} else {
q.selection = fieldPaths
}
return q
}
// Where returns a new Query that filters the set of results.
// A Query can have multiple filters.
// The path argument can be a single field or a dot-separated sequence of
// fields, and must not contain any of the runes "˜*/[]".
// The op argument must be one of "==", "<", "<=", ">" or ">=".
func (q Query) Where(path, op string, value interface{}) Query {
fp, err := parseDotSeparatedString(path)
if err != nil {
q.err = err
return q
}
q.filters = append(append([]filter(nil), q.filters...), filter{fp, op, value})
return q
}
// WherePath returns a new Query that filters the set of results.
// A Query can have multiple filters.
// The op argument must be one of "==", "<", "<=", ">" or ">=".
func (q Query) WherePath(fp FieldPath, op string, value interface{}) Query {
q.filters = append(append([]filter(nil), q.filters...), filter{fp, op, value})
return q
}
// Direction is the sort direction for result ordering.
type Direction int32
const (
// Asc sorts results from smallest to largest.
Asc Direction = Direction(pb.StructuredQuery_ASCENDING)
// Desc sorts results from largest to smallest.
Desc Direction = Direction(pb.StructuredQuery_DESCENDING)
)
// OrderBy returns a new Query that specifies the order in which results are
// returned. A Query can have multiple OrderBy/OrderByPath specifications. OrderBy
// appends the specification to the list of existing ones.
//
// The path argument can be a single field or a dot-separated sequence of
// fields, and must not contain any of the runes "˜*/[]".
//
// To order by document name, use the special field path DocumentID.
func (q Query) OrderBy(path string, dir Direction) Query {
fp, err := parseDotSeparatedString(path)
if err != nil {
q.err = err
return q
}
q.orders = append(q.copyOrders(), order{fp, dir})
return q
}
// OrderByPath returns a new Query that specifies the order in which results are
// returned. A Query can have multiple OrderBy/OrderByPath specifications.
// OrderByPath appends the specification to the list of existing ones.
func (q Query) OrderByPath(fp FieldPath, dir Direction) Query {
q.orders = append(q.copyOrders(), order{fp, dir})
return q
}
func (q *Query) copyOrders() []order {
return append([]order(nil), q.orders...)
}
// Offset returns a new Query that specifies the number of initial results to skip.
// It must not be negative.
func (q Query) Offset(n int) Query {
q.offset = trunc32(n)
return q
}
// Limit returns a new Query that specifies the maximum number of results to return.
// It must not be negative.
func (q Query) Limit(n int) Query {
q.limit = &wrappers.Int32Value{Value: trunc32(n)}
return q
}
// StartAt returns a new Query that specifies that results should start at
// the document with the given field values.
//
// StartAt may be called with a single DocumentSnapshot, representing an
// existing document within the query. The document must be a direct child of
// the location being queried (not a parent document, or document in a
// different collection, or a grandchild document, for example).
//
// Otherwise, StartAt should be called with one field value for each OrderBy clause,
// in the order that they appear. For example, in
// q.OrderBy("X", Asc).OrderBy("Y", Desc).StartAt(1, 2)
// results will begin at the first document where X = 1 and Y = 2.
//
// If an OrderBy call uses the special DocumentID field path, the corresponding value
// should be the document ID relative to the query's collection. For example, to
// start at the document "NewYork" in the "States" collection, write
//
// client.Collection("States").OrderBy(DocumentID, firestore.Asc).StartAt("NewYork")
//
// Calling StartAt overrides a previous call to StartAt or StartAfter.
func (q Query) StartAt(docSnapshotOrFieldValues ...interface{}) Query {
q.startBefore = true
q.startVals, q.startDoc, q.err = q.processCursorArg("StartAt", docSnapshotOrFieldValues)
return q
}
// StartAfter returns a new Query that specifies that results should start just after
// the document with the given field values. See Query.StartAt for more information.
//
// Calling StartAfter overrides a previous call to StartAt or StartAfter.
func (q Query) StartAfter(docSnapshotOrFieldValues ...interface{}) Query {
q.startBefore = false
q.startVals, q.startDoc, q.err = q.processCursorArg("StartAfter", docSnapshotOrFieldValues)
return q
}
// EndAt returns a new Query that specifies that results should end at the
// document with the given field values. See Query.StartAt for more information.
//
// Calling EndAt overrides a previous call to EndAt or EndBefore.
func (q Query) EndAt(docSnapshotOrFieldValues ...interface{}) Query {
q.endBefore = false
q.endVals, q.endDoc, q.err = q.processCursorArg("EndAt", docSnapshotOrFieldValues)
return q
}
// EndBefore returns a new Query that specifies that results should end just before
// the document with the given field values. See Query.StartAt for more information.
//
// Calling EndBefore overrides a previous call to EndAt or EndBefore.
func (q Query) EndBefore(docSnapshotOrFieldValues ...interface{}) Query {
q.endBefore = true
q.endVals, q.endDoc, q.err = q.processCursorArg("EndBefore", docSnapshotOrFieldValues)
return q
}
func (q *Query) processCursorArg(name string, docSnapshotOrFieldValues []interface{}) ([]interface{}, *DocumentSnapshot, error) {
for _, e := range docSnapshotOrFieldValues {
if ds, ok := e.(*DocumentSnapshot); ok {
if len(docSnapshotOrFieldValues) == 1 {
return nil, ds, nil
}
return nil, nil, fmt.Errorf("firestore: a document snapshot must be the only argument to %s", name)
}
}
return docSnapshotOrFieldValues, nil, nil
}
func (q Query) query() *Query { return &q }
func (q Query) toProto() (*pb.StructuredQuery, error) {
if q.err != nil {
return nil, q.err
}
if q.collectionID == "" {
return nil, errors.New("firestore: query created without CollectionRef")
}
if q.startBefore {
if len(q.startVals) == 0 && q.startDoc == nil {
return nil, errors.New("firestore: StartAt/StartAfter must be called with at least one value")
}
}
if q.endBefore {
if len(q.endVals) == 0 && q.endDoc == nil {
return nil, errors.New("firestore: EndAt/EndBefore must be called with at least one value")
}
}
p := &pb.StructuredQuery{
From: []*pb.StructuredQuery_CollectionSelector{{CollectionId: q.collectionID}},
Offset: q.offset,
Limit: q.limit,
}
if len(q.selection) > 0 {
p.Select = &pb.StructuredQuery_Projection{}
for _, fp := range q.selection {
if err := fp.validate(); err != nil {
return nil, err
}
p.Select.Fields = append(p.Select.Fields, fref(fp))
}
}
// If there is only filter, use it directly. Otherwise, construct
// a CompositeFilter.
if len(q.filters) == 1 {
pf, err := q.filters[0].toProto()
if err != nil {
return nil, err
}
p.Where = pf
} else if len(q.filters) > 1 {
cf := &pb.StructuredQuery_CompositeFilter{
Op: pb.StructuredQuery_CompositeFilter_AND,
}
p.Where = &pb.StructuredQuery_Filter{
FilterType: &pb.StructuredQuery_Filter_CompositeFilter{cf},
}
for _, f := range q.filters {
pf, err := f.toProto()
if err != nil {
return nil, err
}
cf.Filters = append(cf.Filters, pf)
}
}
orders := q.orders
if q.startDoc != nil || q.endDoc != nil {
orders = q.adjustOrders()
}
for _, ord := range orders {
po, err := ord.toProto()
if err != nil {
return nil, err
}
p.OrderBy = append(p.OrderBy, po)
}
cursor, err := q.toCursor(q.startVals, q.startDoc, q.startBefore, orders)
if err != nil {
return nil, err
}
p.StartAt = cursor
cursor, err = q.toCursor(q.endVals, q.endDoc, q.endBefore, orders)
if err != nil {
return nil, err
}
p.EndAt = cursor
return p, nil
}
// If there is a start/end that uses a Document Snapshot, we may need to adjust the OrderBy
// clauses that the user provided: we add OrderBy(__name__) if it isn't already present, and
// we make sure we don't invalidate the original query by adding an OrderBy for inequality filters.
func (q *Query) adjustOrders() []order {
// If the user is already ordering by document ID, don't change anything.
for _, ord := range q.orders {
if ord.isDocumentID() {
return q.orders
}
}
// If there are OrderBy clauses, append an OrderBy(DocumentID), using the direction of the last OrderBy clause.
if len(q.orders) > 0 {
return append(q.copyOrders(), order{
fieldPath: FieldPath{DocumentID},
dir: q.orders[len(q.orders)-1].dir,
})
}
// If there are no OrderBy clauses but there is an inequality, add an OrderBy clause
// for the field of the first inequality.
var orders []order
for _, f := range q.filters {
if f.op != "==" {
orders = []order{{fieldPath: f.fieldPath, dir: Asc}}
break
}
}
// Add an ascending OrderBy(DocumentID).
return append(orders, order{fieldPath: FieldPath{DocumentID}, dir: Asc})
}
func (q *Query) toCursor(fieldValues []interface{}, ds *DocumentSnapshot, before bool, orders []order) (*pb.Cursor, error) {
var vals []*pb.Value
var err error
if ds != nil {
vals, err = q.docSnapshotToCursorValues(ds, orders)
} else if len(fieldValues) != 0 {
vals, err = q.fieldValuesToCursorValues(fieldValues)
} else {
return nil, nil
}
if err != nil {
return nil, err
}
return &pb.Cursor{Values: vals, Before: before}, nil
}
// toPositionValues converts the field values to protos.
func (q *Query) fieldValuesToCursorValues(fieldValues []interface{}) ([]*pb.Value, error) {
if len(fieldValues) != len(q.orders) {
return nil, errors.New("firestore: number of field values in StartAt/StartAfter/EndAt/EndBefore does not match number of OrderBy fields")
}
vals := make([]*pb.Value, len(fieldValues))
var err error
for i, ord := range q.orders {
fval := fieldValues[i]
if ord.isDocumentID() {
// TODO(jba): support DocumentRefs as well as strings.
// TODO(jba): error if document ref does not belong to the right collection.
docID, ok := fval.(string)
if !ok {
return nil, fmt.Errorf("firestore: expected doc ID for DocumentID field, got %T", fval)
}
vals[i] = &pb.Value{ValueType: &pb.Value_ReferenceValue{q.path + "/" + docID}}
} else {
var sawTransform bool
vals[i], sawTransform, err = toProtoValue(reflect.ValueOf(fval))
if err != nil {
return nil, err
}
if sawTransform {
return nil, errors.New("firestore: transforms disallowed in query value")
}
}
}
return vals, nil
}
func (q *Query) docSnapshotToCursorValues(ds *DocumentSnapshot, orders []order) ([]*pb.Value, error) {
// TODO(jba): error if doc snap does not belong to the right collection.
vals := make([]*pb.Value, len(orders))
for i, ord := range orders {
if ord.isDocumentID() {
dp, qp := ds.Ref.Parent.Path, q.path
if dp != qp {
return nil, fmt.Errorf("firestore: document snapshot for %s passed to query on %s", dp, qp)
}
vals[i] = &pb.Value{ValueType: &pb.Value_ReferenceValue{ds.Ref.Path}}
} else {
val, err := valueAtPath(ord.fieldPath, ds.proto.Fields)
if err != nil {
return nil, err
}
vals[i] = val
}
}
return vals, nil
}
// Returns a function that compares DocumentSnapshots according to q's ordering.
func (q Query) compareFunc() func(d1, d2 *DocumentSnapshot) (int, error) {
// Add implicit sorting by name, using the last specified direction.
lastDir := Asc
if len(q.orders) > 0 {
lastDir = q.orders[len(q.orders)-1].dir
}
orders := append(q.copyOrders(), order{[]string{DocumentID}, lastDir})
return func(d1, d2 *DocumentSnapshot) (int, error) {
for _, ord := range orders {
var cmp int
if len(ord.fieldPath) == 1 && ord.fieldPath[0] == DocumentID {
cmp = compareReferences(d1.Ref.Path, d2.Ref.Path)
} else {
v1, err := valueAtPath(ord.fieldPath, d1.proto.Fields)
if err != nil {
return 0, err
}
v2, err := valueAtPath(ord.fieldPath, d2.proto.Fields)
if err != nil {
return 0, err
}
cmp = compareValues(v1, v2)
}
if cmp != 0 {
if ord.dir == Desc {
cmp = -cmp
}
return cmp, nil
}
}
return 0, nil
}
}
type filter struct {
fieldPath FieldPath
op string
value interface{}
}
func (f filter) toProto() (*pb.StructuredQuery_Filter, error) {
if err := f.fieldPath.validate(); err != nil {
return nil, err
}
if uop, ok := unaryOpFor(f.value); ok {
if f.op != "==" {
return nil, fmt.Errorf("firestore: must use '==' when comparing %v", f.value)
}
return &pb.StructuredQuery_Filter{
FilterType: &pb.StructuredQuery_Filter_UnaryFilter{
UnaryFilter: &pb.StructuredQuery_UnaryFilter{
OperandType: &pb.StructuredQuery_UnaryFilter_Field{
Field: fref(f.fieldPath),
},
Op: uop,
},
},
}, nil
}
var op pb.StructuredQuery_FieldFilter_Operator
switch f.op {
case "<":
op = pb.StructuredQuery_FieldFilter_LESS_THAN
case "<=":
op = pb.StructuredQuery_FieldFilter_LESS_THAN_OR_EQUAL
case ">":
op = pb.StructuredQuery_FieldFilter_GREATER_THAN
case ">=":
op = pb.StructuredQuery_FieldFilter_GREATER_THAN_OR_EQUAL
case "==":
op = pb.StructuredQuery_FieldFilter_EQUAL
case "array-contains":
op = pb.StructuredQuery_FieldFilter_ARRAY_CONTAINS
default:
return nil, fmt.Errorf("firestore: invalid operator %q", f.op)
}
val, sawTransform, err := toProtoValue(reflect.ValueOf(f.value))
if err != nil {
return nil, err
}
if sawTransform {
return nil, errors.New("firestore: transforms disallowed in query value")
}
return &pb.StructuredQuery_Filter{
FilterType: &pb.StructuredQuery_Filter_FieldFilter{
FieldFilter: &pb.StructuredQuery_FieldFilter{
Field: fref(f.fieldPath),
Op: op,
Value: val,
},
},
}, nil
}
func unaryOpFor(value interface{}) (pb.StructuredQuery_UnaryFilter_Operator, bool) {
switch {
case value == nil:
return pb.StructuredQuery_UnaryFilter_IS_NULL, true
case isNaN(value):
return pb.StructuredQuery_UnaryFilter_IS_NAN, true
default:
return pb.StructuredQuery_UnaryFilter_OPERATOR_UNSPECIFIED, false
}
}
func isNaN(x interface{}) bool {
switch x := x.(type) {
case float32:
return math.IsNaN(float64(x))
case float64:
return math.IsNaN(x)
default:
return false
}
}
type order struct {
fieldPath FieldPath
dir Direction
}
func (r order) isDocumentID() bool {
return len(r.fieldPath) == 1 && r.fieldPath[0] == DocumentID
}
func (r order) toProto() (*pb.StructuredQuery_Order, error) {
if err := r.fieldPath.validate(); err != nil {
return nil, err
}
return &pb.StructuredQuery_Order{
Field: fref(r.fieldPath),
Direction: pb.StructuredQuery_Direction(r.dir),
}, nil
}
func fref(fp FieldPath) *pb.StructuredQuery_FieldReference {
return &pb.StructuredQuery_FieldReference{FieldPath: fp.toServiceFieldPath()}
}
func trunc32(i int) int32 {
if i > math.MaxInt32 {
i = math.MaxInt32
}
return int32(i)
}
// Documents returns an iterator over the query's resulting documents.
func (q Query) Documents(ctx context.Context) *DocumentIterator {
return &DocumentIterator{
iter: newQueryDocumentIterator(withResourceHeader(ctx, q.c.path()), &q, nil),
}
}
// DocumentIterator is an iterator over documents returned by a query.
type DocumentIterator struct {
iter docIterator
err error
}
// Unexported interface so we can have two different kinds of DocumentIterator: one
// for straight queries, and one for query snapshots. We do it this way instead of
// making DocumentIterator an interface because in the client libraries, iterators are
// always concrete types, and the fact that this one has two different implementations
// is an internal detail.
type docIterator interface {
next() (*DocumentSnapshot, error)
stop()
}
// Next returns the next result. Its second return value is iterator.Done if there
// are no more results. Once Next returns Done, all subsequent calls will return
// Done.
func (it *DocumentIterator) Next() (*DocumentSnapshot, error) {
if it.err != nil {
return nil, it.err
}
ds, err := it.iter.next()
if err != nil {
it.err = err
}
return ds, err
}
// Stop stops the iterator, freeing its resources.
// Always call Stop when you are done with a DocumentIterator.
// It is not safe to call Stop concurrently with Next.
func (it *DocumentIterator) Stop() {
if it.iter != nil { // possible in error cases
it.iter.stop()
}
if it.err == nil {
it.err = iterator.Done
}
}
// GetAll returns all the documents remaining from the iterator.
// It is not necessary to call Stop on the iterator after calling GetAll.
func (it *DocumentIterator) GetAll() ([]*DocumentSnapshot, error) {
defer it.Stop()
var docs []*DocumentSnapshot
for {
doc, err := it.Next()
if err == iterator.Done {
break
}
if err != nil {
return nil, err
}
docs = append(docs, doc)
}
return docs, nil
}
type queryDocumentIterator struct {
ctx context.Context
cancel func()
q *Query
tid []byte // transaction ID, if any
streamClient pb.Firestore_RunQueryClient
}
func newQueryDocumentIterator(ctx context.Context, q *Query, tid []byte) *queryDocumentIterator {
ctx, cancel := context.WithCancel(ctx)
return &queryDocumentIterator{
ctx: ctx,
cancel: cancel,
q: q,
tid: tid,
}
}
func (it *queryDocumentIterator) next() (*DocumentSnapshot, error) {
client := it.q.c
if it.streamClient == nil {
sq, err := it.q.toProto()
if err != nil {
return nil, err
}
req := &pb.RunQueryRequest{
Parent: it.q.parentPath,
QueryType: &pb.RunQueryRequest_StructuredQuery{sq},
}
if it.tid != nil {
req.ConsistencySelector = &pb.RunQueryRequest_Transaction{it.tid}
}
it.streamClient, err = client.c.RunQuery(it.ctx, req)
if err != nil {
return nil, err
}
}
var res *pb.RunQueryResponse
var err error
for {
res, err = it.streamClient.Recv()
if err == io.EOF {
return nil, iterator.Done
}
if err != nil {
return nil, err
}
if res.Document != nil {
break
}
// No document => partial progress; keep receiving.
}
docRef, err := pathToDoc(res.Document.Name, client)
if err != nil {
return nil, err
}
doc, err := newDocumentSnapshot(docRef, res.Document, client, res.ReadTime)
if err != nil {
return nil, err
}
return doc, nil
}
func (it *queryDocumentIterator) stop() {
it.cancel()
}
// Snapshots returns an iterator over snapshots of the query. Each time the query
// results change, a new snapshot will be generated.
func (q Query) Snapshots(ctx context.Context) *QuerySnapshotIterator {
ws, err := newWatchStreamForQuery(ctx, q)
if err != nil {
return &QuerySnapshotIterator{err: err}
}
return &QuerySnapshotIterator{
Query: q,
ws: ws,
}
}
// QuerySnapshotIterator is an iterator over snapshots of a query.
// Call Next on the iterator to get a snapshot of the query's results each time they change.
// Call Stop on the iterator when done.
//
// For an example, see Query.Snapshots.
type QuerySnapshotIterator struct {
// The Query used to construct this iterator.
Query Query
ws *watchStream
err error
}
// Next blocks until the query's results change, then returns a QuerySnapshot for
// the current results.
//
// Next never returns iterator.Done unless it is called after Stop.
func (it *QuerySnapshotIterator) Next() (*QuerySnapshot, error) {
if it.err != nil {
return nil, it.err
}
btree, changes, readTime, err := it.ws.nextSnapshot()
if err != nil {
if err == io.EOF {
err = iterator.Done
}
it.err = err
return nil, it.err
}
return &QuerySnapshot{
Documents: &DocumentIterator{
iter: (*btreeDocumentIterator)(btree.BeforeIndex(0)),
},
Size: btree.Len(),
Changes: changes,
ReadTime: readTime,
}, nil
}
// Stop stops receiving snapshots. You should always call Stop when you are done with
// a QuerySnapshotIterator, to free up resources. It is not safe to call Stop
// concurrently with Next.
func (it *QuerySnapshotIterator) Stop() {
if it.ws != nil {
it.ws.stop()
}
}
// A QuerySnapshot is a snapshot of query results. It is returned by
// QuerySnapshotIterator.Next whenever the results of a query change.
type QuerySnapshot struct {
// An iterator over the query results.
// It is not necessary to call Stop on this iterator.
Documents *DocumentIterator
// The number of results in this snapshot.
Size int
// The changes since the previous snapshot.
Changes []DocumentChange
// The time at which this snapshot was obtained from Firestore.
ReadTime time.Time
}
type btreeDocumentIterator btree.Iterator
func (it *btreeDocumentIterator) next() (*DocumentSnapshot, error) {
if !(*btree.Iterator)(it).Next() {
return nil, iterator.Done
}
return it.Key.(*DocumentSnapshot), nil
}
func (*btreeDocumentIterator) stop() {}