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686 lines
16 KiB
686 lines
16 KiB
package autofile
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import (
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"bufio"
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"errors"
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"fmt"
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"io"
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"log"
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"os"
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"path"
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"path/filepath"
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"regexp"
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"strconv"
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"strings"
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"sync"
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"time"
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. "github.com/tendermint/tmlibs/common"
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)
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const (
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groupCheckDuration = 5000 * time.Millisecond
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defaultHeadSizeLimit = 10 * 1024 * 1024 // 10MB
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defaultTotalSizeLimit = 1 * 1024 * 1024 * 1024 // 1GB
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maxFilesToRemove = 4 // needs to be greater than 1
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)
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/*
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You can open a Group to keep restrictions on an AutoFile, like
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the maximum size of each chunk, and/or the total amount of bytes
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stored in the group.
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The first file to be written in the Group.Dir is the head file.
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Dir/
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- <HeadPath>
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Once the Head file reaches the size limit, it will be rotated.
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Dir/
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- <HeadPath>.000 // First rolled file
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- <HeadPath> // New head path, starts empty.
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// The implicit index is 001.
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As more files are written, the index numbers grow...
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Dir/
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- <HeadPath>.000 // First rolled file
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- <HeadPath>.001 // Second rolled file
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- ...
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- <HeadPath> // New head path
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The Group can also be used to binary-search for some line,
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assuming that marker lines are written occasionally.
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*/
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type Group struct {
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BaseService
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ID string
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Head *AutoFile // The head AutoFile to write to
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headBuf *bufio.Writer
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Dir string // Directory that contains .Head
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ticker *time.Ticker
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mtx sync.Mutex
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headSizeLimit int64
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totalSizeLimit int64
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minIndex int // Includes head
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maxIndex int // Includes head, where Head will move to
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// TODO: When we start deleting files, we need to start tracking GroupReaders
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// and their dependencies.
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}
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func OpenGroup(headPath string) (g *Group, err error) {
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dir := path.Dir(headPath)
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head, err := OpenAutoFile(headPath)
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if err != nil {
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return nil, err
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}
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g = &Group{
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ID: "group:" + head.ID,
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Head: head,
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headBuf: bufio.NewWriterSize(head, 4096*10),
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Dir: dir,
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ticker: time.NewTicker(groupCheckDuration),
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headSizeLimit: defaultHeadSizeLimit,
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totalSizeLimit: defaultTotalSizeLimit,
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minIndex: 0,
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maxIndex: 0,
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}
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g.BaseService = *NewBaseService(nil, "Group", g)
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gInfo := g.readGroupInfo()
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g.minIndex = gInfo.MinIndex
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g.maxIndex = gInfo.MaxIndex
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return
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}
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func (g *Group) OnStart() error {
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g.BaseService.OnStart()
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go g.processTicks()
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return nil
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}
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// NOTE: g.Head must be closed separately
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func (g *Group) OnStop() {
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g.BaseService.OnStop()
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g.ticker.Stop()
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}
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// SetHeadSizeLimit allows you to overwrite default head size limit - 10MB.
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func (g *Group) SetHeadSizeLimit(limit int64) {
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g.mtx.Lock()
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g.headSizeLimit = limit
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g.mtx.Unlock()
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}
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// HeadSizeLimit returns the current head size limit.
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func (g *Group) HeadSizeLimit() int64 {
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g.mtx.Lock()
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defer g.mtx.Unlock()
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return g.headSizeLimit
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}
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// SetTotalSizeLimit allows you to overwrite default total size limit of the
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// group - 1GB.
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func (g *Group) SetTotalSizeLimit(limit int64) {
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g.mtx.Lock()
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g.totalSizeLimit = limit
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g.mtx.Unlock()
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}
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// TotalSizeLimit returns total size limit of the group.
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func (g *Group) TotalSizeLimit() int64 {
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g.mtx.Lock()
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defer g.mtx.Unlock()
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return g.totalSizeLimit
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}
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// MaxIndex returns index of the last file in the group.
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func (g *Group) MaxIndex() int {
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g.mtx.Lock()
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defer g.mtx.Unlock()
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return g.maxIndex
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}
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// WriteLine writes line into the current head of the group. It also appends "\n".
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// NOTE: Writes are buffered so they don't write synchronously
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// TODO: Make it halt if space is unavailable
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func (g *Group) WriteLine(line string) error {
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g.mtx.Lock()
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defer g.mtx.Unlock()
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_, err := g.headBuf.Write([]byte(line + "\n"))
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return err
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}
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// Flush writes any buffered data to the underlying file and commits the
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// current content of the file to stable storage.
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func (g *Group) Flush() error {
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g.mtx.Lock()
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defer g.mtx.Unlock()
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err := g.headBuf.Flush()
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if err == nil {
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err = g.Head.Sync()
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}
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return err
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}
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func (g *Group) processTicks() {
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for {
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_, ok := <-g.ticker.C
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if !ok {
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return // Done.
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}
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g.checkHeadSizeLimit()
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g.checkTotalSizeLimit()
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}
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}
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// NOTE: for testing
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func (g *Group) stopTicker() {
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g.ticker.Stop()
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}
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// NOTE: this function is called manually in tests.
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func (g *Group) checkHeadSizeLimit() {
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limit := g.HeadSizeLimit()
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if limit == 0 {
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return
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}
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size, err := g.Head.Size()
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if err != nil {
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panic(err)
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}
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if size >= limit {
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g.RotateFile()
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}
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}
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func (g *Group) checkTotalSizeLimit() {
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limit := g.TotalSizeLimit()
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if limit == 0 {
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return
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}
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gInfo := g.readGroupInfo()
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totalSize := gInfo.TotalSize
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for i := 0; i < maxFilesToRemove; i++ {
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index := gInfo.MinIndex + i
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if totalSize < limit {
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return
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}
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if index == gInfo.MaxIndex {
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// Special degenerate case, just do nothing.
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log.Println("WARNING: Group's head " + g.Head.Path + "may grow without bound")
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return
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}
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pathToRemove := filePathForIndex(g.Head.Path, index, gInfo.MaxIndex)
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fileInfo, err := os.Stat(pathToRemove)
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if err != nil {
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log.Println("WARNING: Failed to fetch info for file @" + pathToRemove)
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continue
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}
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err = os.Remove(pathToRemove)
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if err != nil {
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log.Println(err)
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return
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}
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totalSize -= fileInfo.Size()
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}
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}
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// RotateFile causes group to close the current head and assign it some index.
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// Note it does not create a new head.
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func (g *Group) RotateFile() {
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g.mtx.Lock()
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defer g.mtx.Unlock()
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headPath := g.Head.Path
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if err := g.Head.closeFile(); err != nil {
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panic(err)
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}
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indexPath := filePathForIndex(headPath, g.maxIndex, g.maxIndex+1)
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if err := os.Rename(headPath, indexPath); err != nil {
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panic(err)
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}
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g.maxIndex += 1
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}
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// NewReader returns a new group reader.
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// CONTRACT: Caller must close the returned GroupReader.
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func (g *Group) NewReader(index int) (*GroupReader, error) {
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r := newGroupReader(g)
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err := r.SetIndex(index)
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if err != nil {
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return nil, err
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} else {
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return r, nil
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}
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}
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// Returns -1 if line comes after, 0 if found, 1 if line comes before.
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type SearchFunc func(line string) (int, error)
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// Searches for the right file in Group, then returns a GroupReader to start
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// streaming lines.
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// Returns true if an exact match was found, otherwise returns the next greater
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// line that starts with prefix.
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// CONTRACT: Caller must close the returned GroupReader
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func (g *Group) Search(prefix string, cmp SearchFunc) (*GroupReader, bool, error) {
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g.mtx.Lock()
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minIndex, maxIndex := g.minIndex, g.maxIndex
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g.mtx.Unlock()
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// Now minIndex/maxIndex may change meanwhile,
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// but it shouldn't be a big deal
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// (maybe we'll want to limit scanUntil though)
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for {
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curIndex := (minIndex + maxIndex + 1) / 2
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// Base case, when there's only 1 choice left.
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if minIndex == maxIndex {
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r, err := g.NewReader(maxIndex)
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if err != nil {
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return nil, false, err
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}
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match, err := scanUntil(r, prefix, cmp)
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if err != nil {
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r.Close()
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return nil, false, err
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} else {
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return r, match, err
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}
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}
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// Read starting roughly at the middle file,
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// until we find line that has prefix.
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r, err := g.NewReader(curIndex)
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if err != nil {
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return nil, false, err
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}
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foundIndex, line, err := scanNext(r, prefix)
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r.Close()
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if err != nil {
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return nil, false, err
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}
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// Compare this line to our search query.
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val, err := cmp(line)
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if err != nil {
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return nil, false, err
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}
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if val < 0 {
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// Line will come later
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minIndex = foundIndex
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} else if val == 0 {
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// Stroke of luck, found the line
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r, err := g.NewReader(foundIndex)
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if err != nil {
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return nil, false, err
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}
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match, err := scanUntil(r, prefix, cmp)
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if !match {
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panic("Expected match to be true")
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}
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if err != nil {
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r.Close()
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return nil, false, err
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} else {
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return r, true, err
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}
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} else {
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// We passed it
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maxIndex = curIndex - 1
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}
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}
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}
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// Scans and returns the first line that starts with 'prefix'
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// Consumes line and returns it.
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func scanNext(r *GroupReader, prefix string) (int, string, error) {
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for {
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line, err := r.ReadLine()
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if err != nil {
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return 0, "", err
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}
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if !strings.HasPrefix(line, prefix) {
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continue
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}
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index := r.CurIndex()
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return index, line, nil
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}
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}
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// Returns true iff an exact match was found.
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// Pushes line, does not consume it.
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func scanUntil(r *GroupReader, prefix string, cmp SearchFunc) (bool, error) {
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for {
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line, err := r.ReadLine()
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if err != nil {
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return false, err
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}
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if !strings.HasPrefix(line, prefix) {
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continue
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}
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val, err := cmp(line)
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if err != nil {
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return false, err
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}
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if val < 0 {
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continue
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} else if val == 0 {
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r.PushLine(line)
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return true, nil
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} else {
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r.PushLine(line)
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return false, nil
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}
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}
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}
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// Searches backwards for the last line in Group with prefix.
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// Scans each file forward until the end to find the last match.
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func (g *Group) FindLast(prefix string) (match string, found bool, err error) {
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g.mtx.Lock()
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minIndex, maxIndex := g.minIndex, g.maxIndex
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g.mtx.Unlock()
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r, err := g.NewReader(maxIndex)
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if err != nil {
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return "", false, err
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}
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defer r.Close()
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// Open files from the back and read
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GROUP_LOOP:
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for i := maxIndex; i >= minIndex; i-- {
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err := r.SetIndex(i)
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if err != nil {
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return "", false, err
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}
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// Scan each line and test whether line matches
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for {
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line, err := r.ReadLine()
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if err == io.EOF {
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if found {
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return match, found, nil
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} else {
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continue GROUP_LOOP
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}
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} else if err != nil {
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return "", false, err
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}
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if strings.HasPrefix(line, prefix) {
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match = line
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found = true
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}
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if r.CurIndex() > i {
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if found {
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return match, found, nil
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} else {
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continue GROUP_LOOP
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}
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}
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}
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}
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return
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}
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// GroupInfo holds information about the group.
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type GroupInfo struct {
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MinIndex int // index of the first file in the group, including head
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MaxIndex int // index of the last file in the group, including head
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TotalSize int64 // total size of the group
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HeadSize int64 // size of the head
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}
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// Returns info after scanning all files in g.Head's dir.
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func (g *Group) ReadGroupInfo() GroupInfo {
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g.mtx.Lock()
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defer g.mtx.Unlock()
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return g.readGroupInfo()
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}
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// Index includes the head.
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// CONTRACT: caller should have called g.mtx.Lock
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func (g *Group) readGroupInfo() GroupInfo {
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groupDir := filepath.Dir(g.Head.Path)
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headBase := filepath.Base(g.Head.Path)
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var minIndex, maxIndex int = -1, -1
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var totalSize, headSize int64 = 0, 0
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dir, err := os.Open(groupDir)
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if err != nil {
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panic(err)
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}
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defer dir.Close()
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fiz, err := dir.Readdir(0)
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if err != nil {
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panic(err)
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}
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// For each file in the directory, filter by pattern
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for _, fileInfo := range fiz {
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if fileInfo.Name() == headBase {
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fileSize := fileInfo.Size()
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totalSize += fileSize
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headSize = fileSize
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continue
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} else if strings.HasPrefix(fileInfo.Name(), headBase) {
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fileSize := fileInfo.Size()
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totalSize += fileSize
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indexedFilePattern := regexp.MustCompile(`^.+\.([0-9]{3,})$`)
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submatch := indexedFilePattern.FindSubmatch([]byte(fileInfo.Name()))
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if len(submatch) != 0 {
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// Matches
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fileIndex, err := strconv.Atoi(string(submatch[1]))
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if err != nil {
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panic(err)
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}
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if maxIndex < fileIndex {
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maxIndex = fileIndex
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}
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if minIndex == -1 || fileIndex < minIndex {
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minIndex = fileIndex
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}
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}
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}
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}
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// Now account for the head.
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if minIndex == -1 {
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// If there were no numbered files,
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// then the head is index 0.
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minIndex, maxIndex = 0, 0
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} else {
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// Otherwise, the head file is 1 greater
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maxIndex += 1
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}
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return GroupInfo{minIndex, maxIndex, totalSize, headSize}
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}
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func filePathForIndex(headPath string, index int, maxIndex int) string {
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if index == maxIndex {
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return headPath
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} else {
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return fmt.Sprintf("%v.%03d", headPath, index)
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}
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}
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//--------------------------------------------------------------------------------
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// GroupReader provides an interface for reading from a Group.
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type GroupReader struct {
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*Group
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mtx sync.Mutex
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curIndex int
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curFile *os.File
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curReader *bufio.Reader
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curLine []byte
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}
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func newGroupReader(g *Group) *GroupReader {
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return &GroupReader{
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Group: g,
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curIndex: 0,
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curFile: nil,
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curReader: nil,
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curLine: nil,
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}
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}
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// Close closes the GroupReader by closing the cursor file.
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func (gr *GroupReader) Close() error {
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gr.mtx.Lock()
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defer gr.mtx.Unlock()
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if gr.curReader != nil {
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err := gr.curFile.Close()
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gr.curIndex = 0
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gr.curReader = nil
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gr.curFile = nil
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gr.curLine = nil
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return err
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} else {
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return nil
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}
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}
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// ReadLine reads a line (without delimiter).
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// just return io.EOF if no new lines found.
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func (gr *GroupReader) ReadLine() (string, error) {
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gr.mtx.Lock()
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defer gr.mtx.Unlock()
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// From PushLine
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if gr.curLine != nil {
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line := string(gr.curLine)
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gr.curLine = nil
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return line, nil
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}
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// Open file if not open yet
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if gr.curReader == nil {
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err := gr.openFile(gr.curIndex)
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if err != nil {
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return "", err
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}
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}
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// Iterate over files until line is found
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var linePrefix string
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for {
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bytesRead, err := gr.curReader.ReadBytes('\n')
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if err == io.EOF {
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// Open the next file
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if err1 := gr.openFile(gr.curIndex + 1); err1 != nil {
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return "", err1
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}
|
|
if len(bytesRead) > 0 && bytesRead[len(bytesRead)-1] == byte('\n') {
|
|
return linePrefix + string(bytesRead[:len(bytesRead)-1]), nil
|
|
} else {
|
|
linePrefix += string(bytesRead)
|
|
continue
|
|
}
|
|
} else if err != nil {
|
|
return "", err
|
|
}
|
|
return linePrefix + string(bytesRead[:len(bytesRead)-1]), nil
|
|
}
|
|
}
|
|
|
|
// IF index > gr.Group.maxIndex, returns io.EOF
|
|
// CONTRACT: caller should hold gr.mtx
|
|
func (gr *GroupReader) openFile(index int) error {
|
|
|
|
// Lock on Group to ensure that head doesn't move in the meanwhile.
|
|
gr.Group.mtx.Lock()
|
|
defer gr.Group.mtx.Unlock()
|
|
|
|
if index > gr.Group.maxIndex {
|
|
return io.EOF
|
|
}
|
|
|
|
curFilePath := filePathForIndex(gr.Head.Path, index, gr.Group.maxIndex)
|
|
curFile, err := os.Open(curFilePath)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
curReader := bufio.NewReader(curFile)
|
|
|
|
// Update gr.cur*
|
|
if gr.curFile != nil {
|
|
gr.curFile.Close() // TODO return error?
|
|
}
|
|
gr.curIndex = index
|
|
gr.curFile = curFile
|
|
gr.curReader = curReader
|
|
gr.curLine = nil
|
|
return nil
|
|
}
|
|
|
|
// PushLine makes the given line the current one, so the next time somebody
|
|
// calls ReadLine, this line will be returned.
|
|
// panics if called twice without calling ReadLine.
|
|
func (gr *GroupReader) PushLine(line string) {
|
|
gr.mtx.Lock()
|
|
defer gr.mtx.Unlock()
|
|
|
|
if gr.curLine == nil {
|
|
gr.curLine = []byte(line)
|
|
} else {
|
|
panic("PushLine failed, already have line")
|
|
}
|
|
}
|
|
|
|
// CurIndex returns cursor's file index.
|
|
func (gr *GroupReader) CurIndex() int {
|
|
gr.mtx.Lock()
|
|
defer gr.mtx.Unlock()
|
|
return gr.curIndex
|
|
}
|
|
|
|
// SetIndex sets the cursor's file index to index by opening a file at this
|
|
// position.
|
|
func (gr *GroupReader) SetIndex(index int) error {
|
|
gr.mtx.Lock()
|
|
defer gr.mtx.Unlock()
|
|
return gr.openFile(index)
|
|
}
|
|
|
|
//--------------------------------------------------------------------------------
|
|
|
|
// A simple SearchFunc that assumes that the marker is of form
|
|
// <prefix><number>.
|
|
// For example, if prefix is '#HEIGHT:', the markers of expected to be of the form:
|
|
//
|
|
// #HEIGHT:1
|
|
// ...
|
|
// #HEIGHT:2
|
|
// ...
|
|
func MakeSimpleSearchFunc(prefix string, target int) SearchFunc {
|
|
return func(line string) (int, error) {
|
|
if !strings.HasPrefix(line, prefix) {
|
|
return -1, errors.New(Fmt("Marker line did not have prefix: %v", prefix))
|
|
}
|
|
i, err := strconv.Atoi(line[len(prefix):])
|
|
if err != nil {
|
|
return -1, errors.New(Fmt("Failed to parse marker line: %v", err.Error()))
|
|
}
|
|
if target < i {
|
|
return 1, nil
|
|
} else if target == i {
|
|
return 0, nil
|
|
} else {
|
|
return -1, nil
|
|
}
|
|
}
|
|
}
|