a2b294f444
We now also have a storagedriver error variable for identifying api calls that are not implemented by drivers (the URLFor method is not implemented by either the filesystem or inmemory drivers)
116 lines
4 KiB
Go
116 lines
4 KiB
Go
package storagedriver
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import (
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"errors"
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"fmt"
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"io"
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"regexp"
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"strconv"
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"strings"
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)
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// Version is a string representing the storage driver version, of the form
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// Major.Minor.
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// The registry must accept storage drivers with equal major version and greater
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// minor version, but may not be compatible with older storage driver versions.
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type Version string
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// Major returns the major (primary) component of a version.
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func (version Version) Major() uint {
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majorPart := strings.Split(string(version), ".")[0]
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major, _ := strconv.ParseUint(majorPart, 10, 0)
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return uint(major)
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}
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// Minor returns the minor (secondary) component of a version.
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func (version Version) Minor() uint {
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minorPart := strings.Split(string(version), ".")[1]
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minor, _ := strconv.ParseUint(minorPart, 10, 0)
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return uint(minor)
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}
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// CurrentVersion is the current storage driver Version.
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const CurrentVersion Version = "0.1"
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// StorageDriver defines methods that a Storage Driver must implement for a
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// filesystem-like key/value object storage.
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type StorageDriver interface {
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// GetContent retrieves the content stored at "path" as a []byte.
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// This should primarily be used for small objects.
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GetContent(path string) ([]byte, error)
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// PutContent stores the []byte content at a location designated by "path".
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// This should primarily be used for small objects.
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PutContent(path string, content []byte) error
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// ReadStream retrieves an io.ReadCloser for the content stored at "path"
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// with a given byte offset.
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// May be used to resume reading a stream by providing a nonzero offset.
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ReadStream(path string, offset int64) (io.ReadCloser, error)
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// WriteStream stores the contents of the provided io.ReadCloser at a
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// location designated by the given path.
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// May be used to resume writing a stream by providing a nonzero offset.
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// The offset must be no larger than the CurrentSize for this path.
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WriteStream(path string, offset int64, reader io.Reader) (nn int64, err error)
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// Stat retrieves the FileInfo for the given path, including the current
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// size in bytes and the creation time.
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Stat(path string) (FileInfo, error)
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// List returns a list of the objects that are direct descendants of the
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//given path.
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List(path string) ([]string, error)
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// Move moves an object stored at sourcePath to destPath, removing the
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// original object.
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// Note: This may be no more efficient than a copy followed by a delete for
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// many implementations.
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Move(sourcePath string, destPath string) error
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// Delete recursively deletes all objects stored at "path" and its subpaths.
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Delete(path string) error
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// URLFor returns a URL which may be used to retrieve the content stored at the given path.
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// May return an UnsupportedMethodErr in certain StorageDriver implementations.
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URLFor(path string) (string, error)
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}
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// PathRegexp is the regular expression which each file path must match.
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// A file path is absolute, beginning with a slash and containing a
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// positive number of path components separated by slashes, where each component
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// is restricted to lowercase alphanumeric characters, optionally separated by
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// a period, underscore, or hyphen.
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var PathRegexp = regexp.MustCompile(`^(/[a-z0-9]+([._-][a-z0-9]+)*)+$`)
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// UnsupportedMethodErr may be returned in the case where a StorageDriver implementation does not support an optional method.
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var ErrUnsupportedMethod = errors.New("Unsupported method")
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// PathNotFoundError is returned when operating on a nonexistent path.
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type PathNotFoundError struct {
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Path string
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}
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func (err PathNotFoundError) Error() string {
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return fmt.Sprintf("Path not found: %s", err.Path)
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}
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// InvalidPathError is returned when the provided path is malformed.
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type InvalidPathError struct {
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Path string
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}
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func (err InvalidPathError) Error() string {
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return fmt.Sprintf("Invalid path: %s", err.Path)
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}
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// InvalidOffsetError is returned when attempting to read or write from an
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// invalid offset.
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type InvalidOffsetError struct {
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Path string
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Offset int64
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}
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func (err InvalidOffsetError) Error() string {
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return fmt.Sprintf("Invalid offset: %d for path: %s", err.Offset, err.Path)
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}
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