Golang Time.Before方法代码示例

// preloadChunksForInstant preloads chunks for the latest value in the given
// range. If the last sample saved in the memorySeries itself is the latest
// value in the given range, it will in fact preload zero chunks and just take
// that value.
func (s *memorySeries) preloadChunksForInstant(
	fp model.Fingerprint,
	from model.Time, through model.Time,
	mss *MemorySeriesStorage,
) (SeriesIterator, error) {
	// If we have a lastSamplePair in the series, and thas last samplePair
	// is in the interval, just take it in a singleSampleSeriesIterator. No
	// need to pin or load anything.
	lastSample := s.lastSamplePair()
	if !through.Before(lastSample.Timestamp) &&
		!from.After(lastSample.Timestamp) &&
		lastSample != model.ZeroSamplePair {
		iter := &boundedIterator{
			it: &singleSampleSeriesIterator{
				samplePair: lastSample,
				metric:     s.metric,
			},
			start: model.Now().Add(-mss.dropAfter),
		}
		return iter, nil
	}
	// If we are here, we are out of luck and have to delegate to the more
	// expensive method.
	return s.preloadChunksForRange(fp, from, through, mss)
}

// preloadChunksForRange loads chunks for the given range from the persistence.
// The caller must have locked the fingerprint of the series.
func (s *memorySeries) preloadChunksForRange(
	fp model.Fingerprint,
	from model.Time, through model.Time,
	mss *MemorySeriesStorage,
) (SeriesIterator, error) {
	firstChunkDescTime := model.Latest
	if len(s.chunkDescs) > 0 {
		firstChunkDescTime = s.chunkDescs[0].FirstTime()
	}
	if s.chunkDescsOffset != 0 && from.Before(firstChunkDescTime) {
		cds, err := mss.loadChunkDescs(fp, s.persistWatermark)
		if err != nil {
			return nopIter, err
		}
		s.chunkDescs = append(cds, s.chunkDescs...)
		s.chunkDescsOffset = 0
		s.persistWatermark += len(cds)
		firstChunkDescTime = s.chunkDescs[0].FirstTime()
	}

	if len(s.chunkDescs) == 0 || through.Before(firstChunkDescTime) {
		return nopIter, nil
	}

	// Find first chunk with start time after "from".
	fromIdx := sort.Search(len(s.chunkDescs), func(i int) bool {
		return s.chunkDescs[i].FirstTime().After(from)
	})
	// Find first chunk with start time after "through".
	throughIdx := sort.Search(len(s.chunkDescs), func(i int) bool {
		return s.chunkDescs[i].FirstTime().After(through)
	})
	if fromIdx == len(s.chunkDescs) {
		// Even the last chunk starts before "from". Find out if the
		// series ends before "from" and we don't need to do anything.
		lt, err := s.chunkDescs[len(s.chunkDescs)-1].LastTime()
		if err != nil {
			return nopIter, err
		}
		if lt.Before(from) {
			return nopIter, nil
		}
	}
	if fromIdx > 0 {
		fromIdx--
	}
	if throughIdx == len(s.chunkDescs) {
		throughIdx--
	}
	if fromIdx > throughIdx {
		// Guard against nonsensical result. The caller will quarantine the series with a meaningful log entry.
		return nopIter, fmt.Errorf("fromIdx=%d is greater than throughIdx=%d, likely caused by data corruption", fromIdx, throughIdx)
	}

	pinIndexes := make([]int, 0, throughIdx-fromIdx+1)
	for i := fromIdx; i <= throughIdx; i++ {
		pinIndexes = append(pinIndexes, i)
	}
	return s.preloadChunks(pinIndexes, fp, mss)
}

// ValueAtTime implements SeriesIterator.
func (it *memorySeriesIterator) ValueAtTime(t model.Time) []model.SamplePair {
	// The most common case. We are iterating through a chunk.
	if it.chunkIt != nil && it.chunkIt.contains(t) {
		return it.chunkIt.valueAtTime(t)
	}

	if len(it.chunks) == 0 {
		return nil
	}

	// Before or exactly on the first sample of the series.
	it.chunkIt = it.chunkIterator(0)
	ts := it.chunkIt.timestampAtIndex(0)
	if !t.After(ts) {
		// return first value of first chunk
		return []model.SamplePair{{
			Timestamp: ts,
			Value:     it.chunkIt.sampleValueAtIndex(0),
		}}
	}

	// After or exactly on the last sample of the series.
	it.chunkIt = it.chunkIterator(len(it.chunks) - 1)
	ts = it.chunkIt.lastTimestamp()
	if !t.Before(ts) {
		// return last value of last chunk
		return []model.SamplePair{{
			Timestamp: ts,
			Value:     it.chunkIt.sampleValueAtIndex(it.chunkIt.length() - 1),
		}}
	}

	// Find last chunk where firstTime() is before or equal to t.
	l := len(it.chunks) - 1
	i := sort.Search(len(it.chunks), func(i int) bool {
		return !it.chunks[l-i].firstTime().After(t)
	})
	if i == len(it.chunks) {
		panic("out of bounds")
	}
	it.chunkIt = it.chunkIterator(l - i)
	ts = it.chunkIt.lastTimestamp()
	if t.After(ts) {
		// We ended up between two chunks.
		sp1 := model.SamplePair{
			Timestamp: ts,
			Value:     it.chunkIt.sampleValueAtIndex(it.chunkIt.length() - 1),
		}
		it.chunkIt = it.chunkIterator(l - i + 1)
		return []model.SamplePair{
			sp1,
			{
				Timestamp: it.chunkIt.timestampAtIndex(0),
				Value:     it.chunkIt.sampleValueAtIndex(0),
			},
		}
	}
	return it.chunkIt.valueAtTime(t)
}

// contains implements Iterator.
func (it *varbitChunkIterator) Contains(t model.Time) (bool, error) {
	last, err := it.LastTimestamp()
	if err != nil {
		it.lastError = err
		return false, err
	}
	return !t.Before(it.c.FirstTime()) &&
		!t.After(last), it.lastError
}

// preloadChunksForRange loads chunks for the given range from the persistence.
// The caller must have locked the fingerprint of the series.
func (s *memorySeries) preloadChunksForRange(
	fp model.Fingerprint,
	from model.Time, through model.Time,
	mss *MemorySeriesStorage,
) (SeriesIterator, error) {
	firstChunkDescTime := model.Latest
	if len(s.chunkDescs) > 0 {
		firstChunkDescTime = s.chunkDescs[0].FirstTime()
	}
	if s.chunkDescsOffset != 0 && from.Before(firstChunkDescTime) {
		cds, err := mss.loadChunkDescs(fp, s.persistWatermark)
		if err != nil {
			return nopIter, err
		}
		s.chunkDescs = append(cds, s.chunkDescs...)
		s.chunkDescsOffset = 0
		s.persistWatermark += len(cds)
		firstChunkDescTime = s.chunkDescs[0].FirstTime()
	}

	if len(s.chunkDescs) == 0 || through.Before(firstChunkDescTime) {
		return nopIter, nil
	}

	// Find first chunk with start time after "from".
	fromIdx := sort.Search(len(s.chunkDescs), func(i int) bool {
		return s.chunkDescs[i].FirstTime().After(from)
	})
	// Find first chunk with start time after "through".
	throughIdx := sort.Search(len(s.chunkDescs), func(i int) bool {
		return s.chunkDescs[i].FirstTime().After(through)
	})
	if fromIdx == len(s.chunkDescs) {
		// Even the last chunk starts before "from". Find out if the
		// series ends before "from" and we don't need to do anything.
		lt, err := s.chunkDescs[len(s.chunkDescs)-1].LastTime()
		if err != nil {
			return nopIter, err
		}
		if lt.Before(from) {
			return nopIter, nil
		}
	}
	if fromIdx > 0 {
		fromIdx--
	}
	if throughIdx == len(s.chunkDescs) {
		throughIdx--
	}

	pinIndexes := make([]int, 0, throughIdx-fromIdx+1)
	for i := fromIdx; i <= throughIdx; i++ {
		pinIndexes = append(pinIndexes, i)
	}
	return s.preloadChunks(pinIndexes, fp, mss)
}

// preloadChunksForRange loads chunks for the given range from the persistence.
// The caller must have locked the fingerprint of the series.
func (s *memorySeries) preloadChunksForRange(
	from model.Time, through model.Time,
	fp model.Fingerprint, mss *memorySeriesStorage,
) ([]*chunkDesc, error) {
	firstChunkDescTime := model.Latest
	if len(s.chunkDescs) > 0 {
		firstChunkDescTime = s.chunkDescs[0].firstTime()
	}
	if s.chunkDescsOffset != 0 && from.Before(firstChunkDescTime) {
		cds, err := mss.loadChunkDescs(fp, s.persistWatermark)
		if err != nil {
			return nil, err
		}
		s.chunkDescs = append(cds, s.chunkDescs...)
		s.chunkDescsOffset = 0
		s.persistWatermark += len(cds)
	}

	if len(s.chunkDescs) == 0 {
		return nil, nil
	}

	// Find first chunk with start time after "from".
	fromIdx := sort.Search(len(s.chunkDescs), func(i int) bool {
		return s.chunkDescs[i].firstTime().After(from)
	})
	// Find first chunk with start time after "through".
	throughIdx := sort.Search(len(s.chunkDescs), func(i int) bool {
		return s.chunkDescs[i].firstTime().After(through)
	})
	if fromIdx > 0 {
		fromIdx--
	}
	if throughIdx == len(s.chunkDescs) {
		throughIdx--
	}

	pinIndexes := make([]int, 0, throughIdx-fromIdx+1)
	for i := fromIdx; i <= throughIdx; i++ {
		pinIndexes = append(pinIndexes, i)
	}
	return s.preloadChunks(pinIndexes, fp, mss)
}

// findAtOrAfter implements Iterator.
func (it *varbitChunkIterator) FindAtOrAfter(t model.Time) bool {
	if it.len == 0 || t.After(it.c.lastTime()) {
		return false
	}
	first := it.c.FirstTime()
	if !t.After(first) {
		it.reset()
		return it.Scan()
	}
	if t == it.t {
		return it.lastError == nil
	}
	if t.Before(it.t) {
		it.reset()
	}
	for it.Scan() && t.After(it.t) {
		// TODO(beorn7): If we are in a repeat, we could iterate forward
		// much faster.
	}
	return it.lastError == nil
}

// findAtOrBefore implements Iterator.
func (it *varbitChunkIterator) FindAtOrBefore(t model.Time) bool {
	if it.len == 0 || t.Before(it.c.FirstTime()) {
		return false
	}
	last := it.c.lastTime()
	if !t.Before(last) {
		it.t = last
		it.v = it.c.lastValue()
		it.pos = it.len + 1
		return true
	}
	if t == it.t {
		return it.lastError == nil
	}
	if t.Before(it.t) || it.rewound {
		it.reset()
	}

	var (
		prevT = model.Earliest
		prevV model.SampleValue
	)
	for it.Scan() && t.After(it.t) {
		prevT = it.t
		prevV = it.v
		// TODO(beorn7): If we are in a repeat, we could iterate forward
		// much faster.
	}
	if t == it.t {
		return it.lastError == nil
	}
	it.rewind(prevT, prevV)
	return it.lastError == nil
}

// metricForRange returns the metric for the given fingerprint if the
// corresponding time series has samples between 'from' and 'through', together
// with a pointer to the series if it is in memory already. For a series that
// does not have samples between 'from' and 'through', the returned bool is
// false. For an archived series that does contain samples between 'from' and
// 'through', it returns (metric, nil, true).
//
// The caller must have locked the fp.
func (s *memorySeriesStorage) metricForRange(
	fp model.Fingerprint,
	from, through model.Time,
) (model.Metric, *memorySeries, bool) {
	series, ok := s.fpToSeries.get(fp)
	if ok {
		if series.lastTime.Before(from) || series.firstTime().After(through) {
			return nil, nil, false
		}
		return series.metric, series, true
	}
	// From here on, we are only concerned with archived metrics.
	// If the high watermark of archived series is before 'from', we are done.
	watermark := model.Time(atomic.LoadInt64((*int64)(&s.archiveHighWatermark)))
	if watermark < from {
		return nil, nil, false
	}
	if from.After(model.Earliest) || through.Before(model.Latest) {
		// The range lookup is relatively cheap, so let's do it first if
		// we have a chance the archived metric is not in the range.
		has, first, last := s.persistence.hasArchivedMetric(fp)
		if !has {
			s.nonExistentSeriesMatchesCount.Inc()
			return nil, nil, false
		}
		if first.After(through) || last.Before(from) {
			return nil, nil, false
		}
	}

	metric, err := s.persistence.archivedMetric(fp)
	if err != nil {
		// archivedMetric has already flagged the storage as dirty in this case.
		return nil, nil, false
	}
	return metric, nil, true
}

func (cd *chunkDesc) contains(t model.Time) bool {
	return !t.Before(cd.firstTime()) && !t.After(cd.lastTime())
}

// dropAndPersistChunks deletes all chunks from a series file whose last sample
// time is before beforeTime, and then appends the provided chunks, leaving out
// those whose last sample time is before beforeTime. It returns the timestamp
// of the first sample in the oldest chunk _not_ dropped, the offset within the
// series file of the first chunk persisted (out of the provided chunks), the
// number of deleted chunks, and true if all chunks of the series have been
// deleted (in which case the returned timestamp will be 0 and must be ignored).
// It is the caller's responsibility to make sure nothing is persisted or loaded
// for the same fingerprint concurrently.
//
// Returning an error signals problems with the series file. In this case, the
// caller should quarantine the series.
func (p *persistence) dropAndPersistChunks(
	fp model.Fingerprint, beforeTime model.Time, chunks []chunk,
) (
	firstTimeNotDropped model.Time,
	offset int,
	numDropped int,
	allDropped bool,
	err error,
) {
	// Style note: With the many return values, it was decided to use naked
	// returns in this method. They make the method more readable, but
	// please handle with care!
	if len(chunks) > 0 {
		// We have chunks to persist. First check if those are already
		// too old. If that's the case, the chunks in the series file
		// are all too old, too.
		i := 0
		for ; i < len(chunks); i++ {
			var lt model.Time
			lt, err = chunks[i].newIterator().lastTimestamp()
			if err != nil {
				return
			}
			if !lt.Before(beforeTime) {
				break
			}
		}
		if i < len(chunks) {
			firstTimeNotDropped = chunks[i].firstTime()
		}
		if i > 0 || firstTimeNotDropped.Before(beforeTime) {
			// Series file has to go.
			if numDropped, err = p.deleteSeriesFile(fp); err != nil {
				return
			}
			numDropped += i
			if i == len(chunks) {
				allDropped = true
				return
			}
			// Now simply persist what has to be persisted to a new file.
			_, err = p.persistChunks(fp, chunks[i:])
			return
		}
	}

	// If we are here, we have to check the series file itself.
	f, err := p.openChunkFileForReading(fp)
	if os.IsNotExist(err) {
		// No series file. Only need to create new file with chunks to
		// persist, if there are any.
		if len(chunks) == 0 {
			allDropped = true
			err = nil // Do not report not-exist err.
			return
		}
		offset, err = p.persistChunks(fp, chunks)
		return
	}
	if err != nil {
		return
	}
	defer f.Close()

	headerBuf := make([]byte, chunkHeaderLen)
	var firstTimeInFile model.Time
	// Find the first chunk in the file that should be kept.
	for ; ; numDropped++ {
		_, err = f.Seek(offsetForChunkIndex(numDropped), os.SEEK_SET)
		if err != nil {
			return
		}
		_, err = io.ReadFull(f, headerBuf)
		if err == io.EOF {
			// Close the file before trying to delete it. This is necessary on Windows
			// (this will cause the defer f.Close to fail, but the error is silently ignored)
			f.Close()
			// We ran into the end of the file without finding any chunks that should
			// be kept. Remove the whole file.
			if numDropped, err = p.deleteSeriesFile(fp); err != nil {
				return
			}
			if len(chunks) == 0 {
				allDropped = true
				return
			}
			offset, err = p.persistChunks(fp, chunks)
			return
//.........这里部分代码省略.........

// contains implements Iterator.
func (it *indexAccessingChunkIterator) Contains(t model.Time) (bool, error) {
	return !t.Before(it.acc.timestampAtIndex(0)) &&
		!t.After(it.acc.timestampAtIndex(it.len-1)), it.acc.err()
}

// contains implements chunkIterator.
func (it *doubleDeltaEncodedChunkIterator) contains(t model.Time) bool {
	return !t.Before(it.baseT) && !t.After(it.timestampAtIndex(it.len-1))
}