Documentation
¶
Overview ¶
Package storage provides storage abstraction for LevelDB.
Index ¶
Constants ¶
This section is empty.
Variables ¶
var ( ErrInvalidFile = errors.New("leveldb/storage: invalid file for argument") ErrLocked = errors.New("leveldb/storage: already locked") ErrClosed = errors.New("leveldb/storage: closed") )
Common error.
Functions ¶
func FileDescOk ¶
FileDescOk returns true if fd is a valid 'file descriptor'.
Types ¶
type ErrCorrupted ¶
ErrCorrupted is the type that wraps errors that indicate corruption of a file. Package storage has its own type instead of using errors.ErrCorrupted to prevent circular import.
func (*ErrCorrupted) Error ¶
func (e *ErrCorrupted) Error() string
type FileType ¶
type FileType int
FileType represent a file type.
const ( TypeManifest FileType = 1 << iota TypeJournal TypeTable TypeTemp TypeAll = TypeManifest | TypeJournal | TypeTable | TypeTemp )
File types.
type Storage ¶
type Storage interface {
// Lock locks the storage. Any subsequent attempt to call Lock will fail
// until the last lock released.
// Caller should call Unlock method after use.
Lock() (Locker, error)
// Log logs a string. This is used for logging.
// An implementation may write to a file, stdout or simply do nothing.
Log(str string)
// SetMeta store 'file descriptor' that can later be acquired using GetMeta
// method. The 'file descriptor' should point to a valid file.
// SetMeta should be implemented in such way that changes should happen
// atomically.
SetMeta(fd FileDesc) error
// GetMeta returns 'file descriptor' stored in meta. The 'file descriptor'
// can be updated using SetMeta method.
// Returns os.ErrNotExist if meta doesn't store any 'file descriptor', or
// 'file descriptor' point to nonexistent file.
GetMeta() (FileDesc, error)
// List returns file descriptors that match the given file types.
// The file types may be OR'ed together.
List(ft FileType) ([]FileDesc, error)
// Open opens file with the given 'file descriptor' read-only.
// Returns os.ErrNotExist error if the file does not exist.
// Returns ErrClosed if the underlying storage is closed.
Open(fd FileDesc) (Reader, error)
// Create creates file with the given 'file descriptor', truncate if already
// exist and opens write-only.
// Returns ErrClosed if the underlying storage is closed.
Create(fd FileDesc) (Writer, error)
// Remove removes file with the given 'file descriptor'.
// Returns ErrClosed if the underlying storage is closed.
Remove(fd FileDesc) error
// Rename renames file from oldfd to newfd.
// Returns ErrClosed if the underlying storage is closed.
Rename(oldfd, newfd FileDesc) error
// Close closes the storage.
// It is valid to call Close multiple times. Other methods should not be
// called after the storage has been closed.
Close() error
}
Storage is the storage. A storage instance must be safe for concurrent use.
func NewMemStorage ¶
func NewMemStorage() Storage
NewMemStorage returns a new memory-backed storage implementation.
func OpenFile ¶
OpenFile returns a new filesystem-backed storage implementation with the given path. This also acquire a file lock, so any subsequent attempt to open the same path will fail.
The storage must be closed after use, by calling Close method.
func OpenSmbFile ¶
func OpenSmbFile(path string, hostname string, share string, user string, passwd string, readOnly bool) (Storage, error)
OpenSmbFile returns a new smb filesystem-backed storage implementation with the given path. This also acquire a file lock, so any subsequent attempt to open the same path will fail.
The smb share storage must be closed after use, by calling Close method.
type Syncer ¶
type Syncer interface {
// Sync commits the current contents of the file to stable storage.
Sync() error
}
Syncer is the interface that wraps basic Sync method.
type Writer ¶
type Writer interface {
io.WriteCloser
Syncer
}
Writer is the interface that groups the basic Write, Sync and Close methods.
Source Files