butils

package
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Published: Nov 21, 2018 License: Apache-2.0 Imports: 17 Imported by: 0

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Index

Constants

View Source
const (
	// Sync indicates that O_DSYNC should be set on the underlying file,
	// ensuring that data writes do not return until the data is flushed
	// to disk.
	Sync = 1 << iota
	// ReadOnly opens the underlying file on a read-only basis.
	ReadOnly
)

Variables

View Source
var (
	// LSMSize has size of the LSM in bytes
	LSMSize *expvar.Map
	// VlogSize has size of the value log in bytes
	VlogSize *expvar.Map
	// PendingWrites tracks the number of pending writes.
	PendingWrites *expvar.Map

	// NumReads has cumulative number of reads
	NumReads *expvar.Int
	// NumWrites has cumulative number of writes
	NumWrites *expvar.Int
	// NumBytesRead has cumulative number of bytes read
	NumBytesRead *expvar.Int
	// NumBytesWritten has cumulative number of bytes written
	NumBytesWritten *expvar.Int
	// NumLSMGets is number of LMS gets
	NumLSMGets *expvar.Map
	// NumLSMBloomHits is number of LMS bloom hits
	NumLSMBloomHits *expvar.Map
	// NumGets is number of gets
	NumGets *expvar.Int
	// NumPuts is number of puts
	NumPuts *expvar.Int
	// NumBlockedPuts is number of blocked puts
	NumBlockedPuts *expvar.Int
	// NumMemtableGets is number of memtable gets
	NumMemtableGets *expvar.Int
)
View Source
var (

	// CastagnoliCrcTable is a CRC32 polynomial btable
	CastagnoliCrcTable = crc32.MakeTable(crc32.Castagnoli)
)
View Source
var ErrEOF = errors.New("End of mapped region")

ErrEOF indicates an end of file when trying to read from a memory mapped file and encountering the end of slice.

Functions

func AssertTrue

func AssertTrue(b bool)

AssertTrue asserts that b is true. Otherwise, it would log fatal.

func AssertTruef

func AssertTruef(b bool, format string, args ...interface{})

AssertTruef is AssertTrue with extra info.

func Check

func Check(err error)

Check logs fatal if err != nil.

func Check2

func Check2(_ interface{}, err error)

Check2 acts as convenience wrapper around Check, using the 2nd argument as error.

func Copy

func Copy(a []byte) []byte

Copy copies a byte slice and returns the copied slice.

func CreateSyncedFile

func CreateSyncedFile(filename string, sync bool) (*os.File, error)

CreateSyncedFile creates a new file (using O_EXCL), errors if it already existed.

func Madvise

func Madvise(b []byte, readahead bool) error

Madvise uses the madvise system call to give advise about the use of memory when using a slice that is memory-mapped to a file. Set the readahead flag to false if page references are expected in random order.

func Mmap

func Mmap(fd *os.File, writable bool, size int64) ([]byte, error)

Mmap uses the mmap system call to memory-map a file. If writable is true, memory protection of the pages is set so that they may be written to as well.

func Munmap

func Munmap(b []byte) error

Munmap unmaps a previously mapped slice.

func OpenExistingFile

func OpenExistingFile(filename string, flags uint32) (*os.File, error)

OpenExistingFile opens an existing file, errors if it doesn't exist.

func OpenSyncedFile

func OpenSyncedFile(filename string, sync bool) (*os.File, error)

OpenSyncedFile creates the file if one doesn't exist.

func OpenTruncFile

func OpenTruncFile(filename string, sync bool) (*os.File, error)

OpenTruncFile opens the file with O_RDWR | O_CREATE | O_TRUNC

func SafeCopy

func SafeCopy(a []byte, src []byte) []byte

SafeCopy does append(a[:0], src...).

func Wrap

func Wrap(err error) error

Wrap wraps errors from external lib.

func Wrapf

func Wrapf(err error, format string, args ...interface{}) error

Wrapf is Wrap with extra info.

Types

type Closer

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

Closer holds the two things we need to close a goroutine and wait for it to finish: a chan to tell the goroutine to shut down, and a WaitGroup with which to wait for it to finish shutting down.

func NewCloser

func NewCloser(initial int) *Closer

NewCloser constructs a new Closer, with an initial count on the WaitGroup.

func (*Closer) AddRunning

func (lc *Closer) AddRunning(delta int)

AddRunning Add()'s delta to the WaitGroup.

func (*Closer) Done

func (lc *Closer) Done()

Done calls Done() on the WaitGroup.

func (*Closer) HasBeenClosed

func (lc *Closer) HasBeenClosed() <-chan struct{}

HasBeenClosed gets signaled when Signal() is called.

func (*Closer) Signal

func (lc *Closer) Signal()

Signal signals the HasBeenClosed signal.

func (*Closer) SignalAndWait

func (lc *Closer) SignalAndWait()

SignalAndWait calls Signal(), then Wait().

func (*Closer) Wait

func (lc *Closer) Wait()

Wait waits on the WaitGroup. (It waits for NewCloser's initial value, AddRunning, and Done calls to balance out.)

type Iterator

type Iterator interface {
	Next()
	Rewind()
	Seek(key []byte)
	Key() []byte
	Value() bval.ValueStruct
	Valid() bool

	// All iterators should be closed so that file garbage collection works.
	Close() error
}

Iterator is an interface for a basic iterator.

type MergeIterator

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

MergeIterator merges multiple iterators. NOTE: MergeIterator owns the array of iterators and is responsible for closing them.

func NewMergeIterator

func NewMergeIterator(iters []Iterator, reversed bool) *MergeIterator

NewMergeIterator returns a new MergeIterator from a list of Iterators.

func (*MergeIterator) Close

func (s *MergeIterator) Close() error

Close implements butils.Iterator

func (*MergeIterator) Key

func (s *MergeIterator) Key() []byte

Key returns the key associated with the current iterator

func (*MergeIterator) Next

func (s *MergeIterator) Next()

Next returns the next element. If it is the same as the current key, ignore it.

func (*MergeIterator) Rewind

func (s *MergeIterator) Rewind()

Rewind seeks to first element (or last element for reverse iterator).

func (*MergeIterator) Seek

func (s *MergeIterator) Seek(key []byte)

Seek brings us to element with key >= given key.

func (*MergeIterator) Valid

func (s *MergeIterator) Valid() bool

Valid returns whether the MergeIterator is at a valid element.

func (*MergeIterator) Value

func (s *MergeIterator) Value() bval.ValueStruct

Value returns the value associated with the iterator.

type Slice

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

Slice holds a reusable buf, will reallocate if you request a larger size than ever before. One problem is with n distinct sizes in random order it'll reallocate log(n) times.

func (*Slice) Resize

func (s *Slice) Resize(sz int) []byte

Resize reuses the Slice's buffer (or makes a new one) and returns a slice in that buffer of length sz.

type WaterMark

type WaterMark struct {
	Name string
	// contains filtered or unexported fields
}

WaterMark is used to keep track of the minimum un-finished index. Typically, an index k becomes finished or "done" according to a WaterMark once Done(k) has been called

  1. as many times as Begin(k) has, AND
  2. a positive number of times.

An index may also become "done" by calling SetDoneUntil at a time such that it is not inter-mingled with Begin/Done calls.

Since doneUntil and lastIndex addresses are passed to sync/atomic packages, we ensure that they are 64-bit aligned by putting them at the beginning of the structure.

func (*WaterMark) Begin

func (w *WaterMark) Begin(index uint64)

func (*WaterMark) BeginMany

func (w *WaterMark) BeginMany(indices []uint64)

func (*WaterMark) Done

func (w *WaterMark) Done(index uint64)

func (*WaterMark) DoneMany

func (w *WaterMark) DoneMany(indices []uint64)

func (*WaterMark) DoneUntil

func (w *WaterMark) DoneUntil() uint64

DoneUntil returns the maximum index until which all tasks are done.

func (*WaterMark) Init

func (w *WaterMark) Init()

Init initializes a WaterMark struct. MUST be called before using it.

func (*WaterMark) LastIndex

func (w *WaterMark) LastIndex() uint64

func (*WaterMark) SetDoneUntil

func (w *WaterMark) SetDoneUntil(val uint64)

func (*WaterMark) WaitForMark

func (w *WaterMark) WaitForMark(ctx context.Context, index uint64) error

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