1/*
2   Copyright The containerd Authors.
3
4   Licensed under the Apache License, Version 2.0 (the "License");
5   you may not use this file except in compliance with the License.
6   You may obtain a copy of the License at
7
8       http://www.apache.org/licenses/LICENSE-2.0
9
10   Unless required by applicable law or agreed to in writing, software
11   distributed under the License is distributed on an "AS IS" BASIS,
12   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   See the License for the specific language governing permissions and
14   limitations under the License.
15*/
16
17package containerd
18
19import (
20	"context"
21
22	diffapi "github.com/containerd/containerd/api/services/diff/v1"
23	"github.com/containerd/containerd/api/types"
24	"github.com/containerd/containerd/diff"
25	"github.com/containerd/containerd/errdefs"
26	"github.com/containerd/containerd/mount"
27	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
28)
29
30// DiffService handles the computation and application of diffs
31type DiffService interface {
32	diff.Comparer
33	diff.Applier
34}
35
36// NewDiffServiceFromClient returns a new diff service which communicates
37// over a GRPC connection.
38func NewDiffServiceFromClient(client diffapi.DiffClient) DiffService {
39	return &diffRemote{
40		client: client,
41	}
42}
43
44type diffRemote struct {
45	client diffapi.DiffClient
46}
47
48func (r *diffRemote) Apply(ctx context.Context, diff ocispec.Descriptor, mounts []mount.Mount) (ocispec.Descriptor, error) {
49	req := &diffapi.ApplyRequest{
50		Diff:   fromDescriptor(diff),
51		Mounts: fromMounts(mounts),
52	}
53	resp, err := r.client.Apply(ctx, req)
54	if err != nil {
55		return ocispec.Descriptor{}, errdefs.FromGRPC(err)
56	}
57	return toDescriptor(resp.Applied), nil
58}
59
60func (r *diffRemote) Compare(ctx context.Context, a, b []mount.Mount, opts ...diff.Opt) (ocispec.Descriptor, error) {
61	var config diff.Config
62	for _, opt := range opts {
63		if err := opt(&config); err != nil {
64			return ocispec.Descriptor{}, err
65		}
66	}
67	req := &diffapi.DiffRequest{
68		Left:      fromMounts(a),
69		Right:     fromMounts(b),
70		MediaType: config.MediaType,
71		Ref:       config.Reference,
72		Labels:    config.Labels,
73	}
74	resp, err := r.client.Diff(ctx, req)
75	if err != nil {
76		return ocispec.Descriptor{}, errdefs.FromGRPC(err)
77	}
78	return toDescriptor(resp.Diff), nil
79}
80
81func toDescriptor(d *types.Descriptor) ocispec.Descriptor {
82	return ocispec.Descriptor{
83		MediaType: d.MediaType,
84		Digest:    d.Digest,
85		Size:      d.Size_,
86	}
87}
88
89func fromDescriptor(d ocispec.Descriptor) *types.Descriptor {
90	return &types.Descriptor{
91		MediaType: d.MediaType,
92		Digest:    d.Digest,
93		Size_:     d.Size,
94	}
95}
96
97func fromMounts(mounts []mount.Mount) []*types.Mount {
98	apiMounts := make([]*types.Mount, len(mounts))
99	for i, m := range mounts {
100		apiMounts[i] = &types.Mount{
101			Type:    m.Type,
102			Source:  m.Source,
103			Options: m.Options,
104		}
105	}
106	return apiMounts
107}
108