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// Copyright 2016 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 storage contains a Google Cloud Storage client.
//
// This package is experimental and may make backwards-incompatible changes.
package storage
import (
"errors"
"fmt"
"reflect"
"golang.org/x/net/context"
raw "google.golang.org/api/storage/v1"
)
// CopierFrom creates a Copier that can copy src to dst.
// You can immediately call Run on the returned Copier, or
// you can configure it first.
func (dst *ObjectHandle) CopierFrom(src *ObjectHandle) *Copier {
return &Copier{dst: dst, src: src}
}
// A Copier copies a source object to a destination.
type Copier struct {
// ObjectAttrs are optional attributes to set on the destination object.
// Any attributes must be initialized before any calls on the Copier. Nil
// or zero-valued attributes are ignored.
ObjectAttrs
// RewriteToken can be set before calling Run to resume a copy
// operation. After Run returns a non-nil error, RewriteToken will
// have been updated to contain the value needed to resume the copy.
RewriteToken string
// ProgressFunc can be used to monitor the progress of a multi-RPC copy
// operation. If ProgressFunc is not nil and CopyFrom requires multiple
// calls to the underlying service (see
// https://cloud.google.com/storage/docs/json_api/v1/objects/rewrite), then
// ProgressFunc will be invoked after each call with the number of bytes of
// content copied so far and the total size in bytes of the source object.
//
// ProgressFunc is intended to make upload progress available to the
// application. For example, the implementation of ProgressFunc may update
// a progress bar in the application's UI, or log the result of
// float64(copiedBytes)/float64(totalBytes).
//
// ProgressFunc should return quickly without blocking.
ProgressFunc func(copiedBytes, totalBytes uint64)
dst, src *ObjectHandle
}
// Run performs the copy.
func (c *Copier) Run(ctx context.Context) (*ObjectAttrs, error) {
if err := c.src.validate(); err != nil {
return nil, err
}
if err := c.dst.validate(); err != nil {
return nil, err
}
var rawObject *raw.Object
// If any attribute was set, then we make sure the name matches the destination
// name, and we check that ContentType is non-empty so we can provide a better
// error message than the service.
if !reflect.DeepEqual(c.ObjectAttrs, ObjectAttrs{}) {
c.ObjectAttrs.Name = c.dst.object
if c.ObjectAttrs.ContentType == "" {
return nil, errors.New("storage: Copier.ContentType must be non-empty")
}
rawObject = c.ObjectAttrs.toRawObject(c.dst.bucket)
}
for {
res, err := c.callRewrite(ctx, c.src, rawObject)
if err != nil {
return nil, err
}
if c.ProgressFunc != nil {
c.ProgressFunc(res.TotalBytesRewritten, res.ObjectSize)
}
if res.Done { // Finished successfully.
return newObject(res.Resource), nil
}
}
return nil, nil
}
func (c *Copier) callRewrite(ctx context.Context, src *ObjectHandle, rawObj *raw.Object) (*raw.RewriteResponse, error) {
call := c.dst.c.raw.Objects.Rewrite(src.bucket, src.object, c.dst.bucket, c.dst.object, rawObj)
call.Context(ctx).Projection("full")
if c.RewriteToken != "" {
call.RewriteToken(c.RewriteToken)
}
if err := applyConds("Copy destination", c.dst.gen, c.dst.conds, call); err != nil {
return nil, err
}
if err := applySourceConds(c.src.gen, c.src.conds, call); err != nil {
return nil, err
}
if err := setEncryptionHeaders(call.Header(), c.dst.encryptionKey, false); err != nil {
return nil, err
}
if err := setEncryptionHeaders(call.Header(), c.src.encryptionKey, true); err != nil {
return nil, err
}
var res *raw.RewriteResponse
var err error
err = runWithRetry(ctx, func() error { res, err = call.Do(); return err })
if err != nil {
return nil, err
}
c.RewriteToken = res.RewriteToken
return res, nil
}
// ComposerFrom creates a Composer that can compose srcs into dst.
// You can immediately call Run on the returned Composer, or you can
// configure it first.
//
// The encryption key for the destination object will be used to decrypt all
// source objects and encrypt the destination object. It is an error
// to specify an encryption key for any of the source objects.
func (dst *ObjectHandle) ComposerFrom(srcs ...*ObjectHandle) *Composer {
return &Composer{dst: dst, srcs: srcs}
}
// A Composer composes source objects into a destination object.
type Composer struct {
// ObjectAttrs are optional attributes to set on the destination object.
// Any attributes must be initialized before any calls on the Composer. Nil
// or zero-valued attributes are ignored.
ObjectAttrs
dst *ObjectHandle
srcs []*ObjectHandle
}
// Run performs the compose operation.
func (c *Composer) Run(ctx context.Context) (*ObjectAttrs, error) {
if err := c.dst.validate(); err != nil {
return nil, err
}
if len(c.srcs) == 0 {
return nil, errors.New("storage: at least one source object must be specified")
}
req := &raw.ComposeRequest{}
// Compose requires a non-empty Destination, so we always set it,
// even if the caller-provided ObjectAttrs is the zero value.
req.Destination = c.ObjectAttrs.toRawObject(c.dst.bucket)
for _, src := range c.srcs {
if err := src.validate(); err != nil {
return nil, err
}
if src.bucket != c.dst.bucket {
return nil, fmt.Errorf("storage: all source objects must be in bucket %q, found %q", c.dst.bucket, src.bucket)
}
if src.encryptionKey != nil {
return nil, fmt.Errorf("storage: compose source %s.%s must not have encryption key", src.bucket, src.object)
}
srcObj := &raw.ComposeRequestSourceObjects{
Name: src.object,
}
if err := applyConds("ComposeFrom source", src.gen, src.conds, composeSourceObj{srcObj}); err != nil {
return nil, err
}
req.SourceObjects = append(req.SourceObjects, srcObj)
}
call := c.dst.c.raw.Objects.Compose(c.dst.bucket, c.dst.object, req).Context(ctx)
if err := applyConds("ComposeFrom destination", c.dst.gen, c.dst.conds, call); err != nil {
return nil, err
}
if err := setEncryptionHeaders(call.Header(), c.dst.encryptionKey, false); err != nil {
return nil, err
}
var obj *raw.Object
var err error
err = runWithRetry(ctx, func() error { obj, err = call.Do(); return err })
if err != nil {
return nil, err
}
return newObject(obj), nil
}
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