Documentation
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Overview ¶
Package file implements a backend.Backend over a local directory tree. Keys map to files under a root; writes are atomic (temp file + rename) so a reader never observes a partially written object — the property the "manifest written last" part commit relies on (DESIGN.md §8, _ref/docs/storage-engine.md §2).
Index ¶
- type File
- func (f *File) Delete(_ context.Context, key string) error
- func (*File) IsEphemeral() bool
- func (f *File) List(_ context.Context, prefix string) ([]string, error)
- func (f *File) PutIfAbsent(_ context.Context, key string, data []byte) (written bool, rerr error)
- func (f *File) Read(_ context.Context, key string) ([]byte, error)
- func (f *File) Size(_ context.Context, key string) (int64, error)
- func (f *File) Write(_ context.Context, key string, data []byte) (rerr error)
Constants ¶
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Variables ¶
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Functions ¶
This section is empty.
Types ¶
type File ¶
type File struct {
// contains filtered or unexported fields
}
File is a directory-backed backend.Backend. Keys are slash-delimited and map to paths under root. Safe for concurrent use (the filesystem serializes renames; reads and writes touch distinct temp files).
func (*File) Delete ¶
Delete removes key, or returns an backend.ErrNotExist-wrapping error if absent.
func (*File) IsEphemeral ¶
IsEphemeral reports false: data persists on disk.
func (*File) PutIfAbsent ¶
PutIfAbsent stores data under key only if it does not already exist, returning whether the write happened. It writes a temp file then hard-links it to the final path: os.Link fails with EEXIST if the destination exists, giving an atomic, exclusive create (the conditional commit primitive). A reader never sees a partial object — the link publishes a fully written file.
func (*File) Read ¶
Read returns the value stored under key, or an backend.ErrNotExist-wrapping error.
func (*File) Size ¶ added in v0.12.0
Size returns the byte size of the object stored under key (os.Stat, no read), or an backend.ErrNotExist-wrapping error if absent. It implements backend.Sizer.
Source Files