Initial

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

vendor/github.com/containerd/containerd/content/content.go

@@ -0,0 +1,182 @@
+/*
+   Copyright The containerd Authors.
+
+   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 content
+
+import (
+	"context"
+	"io"
+	"time"
+
+	"github.com/opencontainers/go-digest"
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
+)
+
+// ReaderAt extends the standard io.ReaderAt interface with reporting of Size and io.Closer
+type ReaderAt interface {
+	io.ReaderAt
+	io.Closer
+	Size() int64
+}
+
+// Provider provides a reader interface for specific content
+type Provider interface {
+	// ReaderAt only requires desc.Digest to be set.
+	// Other fields in the descriptor may be used internally for resolving
+	// the location of the actual data.
+	ReaderAt(ctx context.Context, dec ocispec.Descriptor) (ReaderAt, error)
+}
+
+// Ingester writes content
+type Ingester interface {
+	// Some implementations require WithRef to be included in opts.
+	Writer(ctx context.Context, opts ...WriterOpt) (Writer, error)
+}
+
+// Info holds content specific information
+//
+// TODO(stevvooe): Consider a very different name for this struct. Info is way
+// to general. It also reads very weird in certain context, like pluralization.
+type Info struct {
+	Digest    digest.Digest
+	Size      int64
+	CreatedAt time.Time
+	UpdatedAt time.Time
+	Labels    map[string]string
+}
+
+// Status of a content operation
+type Status struct {
+	Ref       string
+	Offset    int64
+	Total     int64
+	Expected  digest.Digest
+	StartedAt time.Time
+	UpdatedAt time.Time
+}
+
+// WalkFunc defines the callback for a blob walk.
+type WalkFunc func(Info) error
+
+// Manager provides methods for inspecting, listing and removing content.
+type Manager interface {
+	// Info will return metadata about content available in the content store.
+	//
+	// If the content is not present, ErrNotFound will be returned.
+	Info(ctx context.Context, dgst digest.Digest) (Info, error)
+
+	// Update updates mutable information related to content.
+	// If one or more fieldpaths are provided, only those
+	// fields will be updated.
+	// Mutable fields:
+	//  labels.*
+	Update(ctx context.Context, info Info, fieldpaths ...string) (Info, error)
+
+	// Walk will call fn for each item in the content store which
+	// match the provided filters. If no filters are given all
+	// items will be walked.
+	Walk(ctx context.Context, fn WalkFunc, filters ...string) error
+
+	// Delete removes the content from the store.
+	Delete(ctx context.Context, dgst digest.Digest) error
+}
+
+// IngestManager provides methods for managing ingests.
+type IngestManager interface {
+	// Status returns the status of the provided ref.
+	Status(ctx context.Context, ref string) (Status, error)
+
+	// ListStatuses returns the status of any active ingestions whose ref match the
+	// provided regular expression. If empty, all active ingestions will be
+	// returned.
+	ListStatuses(ctx context.Context, filters ...string) ([]Status, error)
+
+	// Abort completely cancels the ingest operation targeted by ref.
+	Abort(ctx context.Context, ref string) error
+}
+
+// Writer handles the write of content into a content store
+type Writer interface {
+	// Close closes the writer, if the writer has not been
+	// committed this allows resuming or aborting.
+	// Calling Close on a closed writer will not error.
+	io.WriteCloser
+
+	// Digest may return empty digest or panics until committed.
+	Digest() digest.Digest
+
+	// Commit commits the blob (but no roll-back is guaranteed on an error).
+	// size and expected can be zero-value when unknown.
+	// Commit always closes the writer, even on error.
+	// ErrAlreadyExists aborts the writer.
+	Commit(ctx context.Context, size int64, expected digest.Digest, opts ...Opt) error
+
+	// Status returns the current state of write
+	Status() (Status, error)
+
+	// Truncate updates the size of the target blob
+	Truncate(size int64) error
+}
+
+// Store combines the methods of content-oriented interfaces into a set that
+// are commonly provided by complete implementations.
+type Store interface {
+	Manager
+	Provider
+	IngestManager
+	Ingester
+}
+
+// Opt is used to alter the mutable properties of content
+type Opt func(*Info) error
+
+// WithLabels allows labels to be set on content
+func WithLabels(labels map[string]string) Opt {
+	return func(info *Info) error {
+		info.Labels = labels
+		return nil
+	}
+}
+
+// WriterOpts is internally used by WriterOpt.
+type WriterOpts struct {
+	Ref  string
+	Desc ocispec.Descriptor
+}
+
+// WriterOpt is used for passing options to Ingester.Writer.
+type WriterOpt func(*WriterOpts) error
+
+// WithDescriptor specifies an OCI descriptor.
+// Writer may optionally use the descriptor internally for resolving
+// the location of the actual data.
+// Write does not require any field of desc to be set.
+// If the data size is unknown, desc.Size should be set to 0.
+// Some implementations may also accept negative values as "unknown".
+func WithDescriptor(desc ocispec.Descriptor) WriterOpt {
+	return func(opts *WriterOpts) error {
+		opts.Desc = desc
+		return nil
+	}
+}
+
+// WithRef specifies a ref string.
+func WithRef(ref string) WriterOpt {
+	return func(opts *WriterOpts) error {
+		opts.Ref = ref
+		return nil
+	}
+}