blob

type Digests struct {
	SHA256 string
	SHA512 string
	SHA1   string
	MD5    string
}

type Hasher struct {
	// contains filtered or unexported fields
}

type Info struct {
	Size    int64
	Digests Digests
}

type PartSizer interface {
	PartSize() int64
}

type SignOptions struct {
	// Via is the route.
	Via Via
	// TTL is how long the URL stays valid once handed out.
	TTL time.Duration
	// Filename and ContentType, when set, travel as response overrides, so
	// the object store answers with the item's name and media type rather
	// than the blob's: the 302 that points at the URL describes no body.
	Filename    string
	ContentType string
}

type Signer interface {
	Signs(via Via) bool
	SignURL(ctx context.Context, sha256 string, o SignOptions) (string, error)
}

type Store interface {
	// BeginUpload starts an upload session.
	BeginUpload(ctx context.Context, opts ...UploadOption) (Upload, error)
	// ResumeUpload reopens a session started earlier, possibly by another
	// request. It returns ErrUploadUnknown for an ID that is not live.
	ResumeUpload(ctx context.Context, id string) (Upload, error)
	// Open returns the content for random access, so HTTP handlers can serve
	// ranges with http.ServeContent. The caller closes it. Info carries Size
	// and Digests.SHA256; SHA512, SHA1 and MD5 may be empty.
	Open(ctx context.Context, sha256 string) (io.ReadSeekCloser, Info, error)
	// Stat returns a blob's Info without opening it.
	Stat(ctx context.Context, sha256 string) (Info, error)
	// Exists reports whether a blob is stored.
	Exists(ctx context.Context, sha256 string) (bool, error)
	// Delete removes a blob. Deleting a missing blob succeeds, because garbage
	// collection and a concurrent delete can race and both mean "gone".
	Delete(ctx context.Context, sha256 string) error
	// Walk calls fn for every stored blob in an unspecified order and stops at
	// the first error fn returns, which Walk returns. Upload sessions are not
	// visited. It exists for garbage collection and storage accounting.
	Walk(ctx context.Context, fn func(Info) error) error
}

type Upload interface {
	// ID names the session for ResumeUpload.
	ID() string
	// Size is the number of bytes appended so far.
	Size() int64
	// Append writes r to the end of the upload and returns how many bytes it
	// stored. On error the bytes counted are stored and hashed, so the session
	// stays consistent and the client may continue from Size.
	Append(ctx context.Context, r io.Reader) (int64, error)
	// Commit finishes the upload. Every non-empty field of want is compared
	// with the computed digest; a mismatch aborts the session and returns
	// ErrDigestMismatch. Content that is already stored is not written again
	// and the session is discarded, so committing the same bytes twice, or
	// from two sessions at once, succeeds both times.
	Commit(ctx context.Context, want Digests) (Info, error)
	// Abort discards the session. Aborting a session that is already gone
	// succeeds.
	Abort(ctx context.Context) error
}

type UploadOption func(*UploadOptions)

type UploadOptions struct {
	// ExpectedSHA256 is the digest the client declared before sending the
	// body (Docker's monolithic PUT ?digest=, X-Checksum-Sha256). Backends
	// that cannot rename use it to write straight to the final key.
	ExpectedSHA256 string
}

type Via int