diff options
Diffstat (limited to 'vendor/github.com/syndtr/goleveldb/leveldb/storage/mem_storage.go')
-rw-r--r-- | vendor/github.com/syndtr/goleveldb/leveldb/storage/mem_storage.go | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/storage/mem_storage.go b/vendor/github.com/syndtr/goleveldb/leveldb/storage/mem_storage.go new file mode 100644 index 000000000..9b0421f03 --- /dev/null +++ b/vendor/github.com/syndtr/goleveldb/leveldb/storage/mem_storage.go @@ -0,0 +1,218 @@ +// Copyright (c) 2013, Suryandaru Triandana <syndtr@gmail.com> +// All rights reserved. +// +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. + +package storage + +import ( + "bytes" + "os" + "sync" +) + +const typeShift = 3 + +type memStorageLock struct { + ms *memStorage +} + +func (lock *memStorageLock) Unlock() { + ms := lock.ms + ms.mu.Lock() + defer ms.mu.Unlock() + if ms.slock == lock { + ms.slock = nil + } + return +} + +// memStorage is a memory-backed storage. +type memStorage struct { + mu sync.Mutex + slock *memStorageLock + files map[uint64]*memFile + meta FileDesc +} + +// NewMemStorage returns a new memory-backed storage implementation. +func NewMemStorage() Storage { + return &memStorage{ + files: make(map[uint64]*memFile), + } +} + +func (ms *memStorage) Lock() (Locker, error) { + ms.mu.Lock() + defer ms.mu.Unlock() + if ms.slock != nil { + return nil, ErrLocked + } + ms.slock = &memStorageLock{ms: ms} + return ms.slock, nil +} + +func (*memStorage) Log(str string) {} + +func (ms *memStorage) SetMeta(fd FileDesc) error { + if !FileDescOk(fd) { + return ErrInvalidFile + } + + ms.mu.Lock() + ms.meta = fd + ms.mu.Unlock() + return nil +} + +func (ms *memStorage) GetMeta() (FileDesc, error) { + ms.mu.Lock() + defer ms.mu.Unlock() + if ms.meta.Zero() { + return FileDesc{}, os.ErrNotExist + } + return ms.meta, nil +} + +func (ms *memStorage) List(ft FileType) ([]FileDesc, error) { + ms.mu.Lock() + var fds []FileDesc + for x := range ms.files { + fd := unpackFile(x) + if fd.Type&ft != 0 { + fds = append(fds, fd) + } + } + ms.mu.Unlock() + return fds, nil +} + +func (ms *memStorage) Open(fd FileDesc) (Reader, error) { + if !FileDescOk(fd) { + return nil, ErrInvalidFile + } + + ms.mu.Lock() + defer ms.mu.Unlock() + if m, exist := ms.files[packFile(fd)]; exist { + if m.open { + return nil, errFileOpen + } + m.open = true + return &memReader{Reader: bytes.NewReader(m.Bytes()), ms: ms, m: m}, nil + } + return nil, os.ErrNotExist +} + +func (ms *memStorage) Create(fd FileDesc) (Writer, error) { + if !FileDescOk(fd) { + return nil, ErrInvalidFile + } + + x := packFile(fd) + ms.mu.Lock() + defer ms.mu.Unlock() + m, exist := ms.files[x] + if exist { + if m.open { + return nil, errFileOpen + } + m.Reset() + } else { + m = &memFile{} + ms.files[x] = m + } + m.open = true + return &memWriter{memFile: m, ms: ms}, nil +} + +func (ms *memStorage) Remove(fd FileDesc) error { + if !FileDescOk(fd) { + return ErrInvalidFile + } + + x := packFile(fd) + ms.mu.Lock() + defer ms.mu.Unlock() + if _, exist := ms.files[x]; exist { + delete(ms.files, x) + return nil + } + return os.ErrNotExist +} + +func (ms *memStorage) Rename(oldfd, newfd FileDesc) error { + if FileDescOk(oldfd) || FileDescOk(newfd) { + return ErrInvalidFile + } + if oldfd == newfd { + return nil + } + + oldx := packFile(oldfd) + newx := packFile(newfd) + ms.mu.Lock() + defer ms.mu.Unlock() + oldm, exist := ms.files[oldx] + if !exist { + return os.ErrNotExist + } + newm, exist := ms.files[newx] + if (exist && newm.open) || oldm.open { + return errFileOpen + } + delete(ms.files, oldx) + ms.files[newx] = oldm + return nil +} + +func (*memStorage) Close() error { return nil } + +type memFile struct { + bytes.Buffer + open bool +} + +type memReader struct { + *bytes.Reader + ms *memStorage + m *memFile + closed bool +} + +func (mr *memReader) Close() error { + mr.ms.mu.Lock() + defer mr.ms.mu.Unlock() + if mr.closed { + return ErrClosed + } + mr.m.open = false + return nil +} + +type memWriter struct { + *memFile + ms *memStorage + closed bool +} + +func (*memWriter) Sync() error { return nil } + +func (mw *memWriter) Close() error { + mw.ms.mu.Lock() + defer mw.ms.mu.Unlock() + if mw.closed { + return ErrClosed + } + mw.memFile.open = false + return nil +} + +func packFile(fd FileDesc) uint64 { + return uint64(fd.Num)<<typeShift | uint64(fd.Type) +} + +func unpackFile(x uint64) FileDesc { + return FileDesc{FileType(x) & TypeAll, int64(x >> typeShift)} +} |