add GDrive provider support (#118)

* GDrive provider support
* More reliable basedir ownership
* Fix mimetype

vendor/cloud.google.com/go/firestore/collref.go

@@ -0,0 +1,114 @@
+// 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 (
+	"math/rand"
+	"os"
+	"sync"
+	"time"
+
+	"golang.org/x/net/context"
+)
+
+// A CollectionRef is a reference to Firestore collection.
+type CollectionRef struct {
+	c *Client
+
+	// Typically Parent.Path, or c.path if Parent is nil.
+	// May be different if this CollectionRef was created from a stored reference
+	// to a different project/DB.
+	parentPath string
+
+	// Parent is the document of which this collection is a part. It is
+	// nil for top-level collections.
+	Parent *DocumentRef
+
+	// The full resource path of the collection: "projects/P/databases/D/documents..."
+	Path string
+
+	// ID is the collection identifier.
+	ID string
+
+	// Use the methods of Query on a CollectionRef to create and run queries.
+	Query
+}
+
+func newTopLevelCollRef(c *Client, dbPath, id string) *CollectionRef {
+	return &CollectionRef{
+		c:          c,
+		ID:         id,
+		parentPath: dbPath,
+		Path:       dbPath + "/documents/" + id,
+		Query:      Query{c: c, collectionID: id, parentPath: dbPath},
+	}
+}
+
+func newCollRefWithParent(c *Client, parent *DocumentRef, id string) *CollectionRef {
+	return &CollectionRef{
+		c:          c,
+		Parent:     parent,
+		ID:         id,
+		parentPath: parent.Path,
+		Path:       parent.Path + "/" + id,
+		Query:      Query{c: c, collectionID: id, parentPath: parent.Path},
+	}
+}
+
+// Doc returns a DocumentRef that refers to the document in the collection with the
+// given identifier.
+func (c *CollectionRef) Doc(id string) *DocumentRef {
+	if c == nil {
+		return nil
+	}
+	return newDocRef(c, id)
+}
+
+// NewDoc returns a DocumentRef with a uniquely generated ID.
+func (c *CollectionRef) NewDoc() *DocumentRef {
+	return c.Doc(uniqueID())
+}
+
+// Add generates a DocumentRef with a unique ID. It then creates the document
+// with the given data, which can be a map[string]interface{}, a struct or a
+// pointer to a struct.
+//
+// Add returns an error in the unlikely event that a document with the same ID
+// already exists.
+func (c *CollectionRef) Add(ctx context.Context, data interface{}) (*DocumentRef, *WriteResult, error) {
+	d := c.NewDoc()
+	wr, err := d.Create(ctx, data)
+	if err != nil {
+		return nil, nil, err
+	}
+	return d, wr, nil
+}
+
+const alphanum = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+
+var (
+	rngMu sync.Mutex
+	rng   = rand.New(rand.NewSource(time.Now().UnixNano() ^ int64(os.Getpid())))
+)
+
+func uniqueID() string {
+	var b [20]byte
+	rngMu.Lock()
+	for i := 0; i < len(b); i++ {
+		b[i] = alphanum[rng.Intn(len(alphanum))]
+	}
+	rngMu.Unlock()
+	return string(b[:])
+}