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Add MakeSimpleSearchFunc

pull/1842/head
Jae Kwon 8 years ago
parent
commit
dc8fa06e64
2 changed files with 45 additions and 5 deletions
  1. +4
    -0
      autofile.go
  2. +41
    -5
      group.go

+ 4
- 0
autofile.go View File

@ -95,6 +95,10 @@ func (af *AutoFile) Write(b []byte) (n int, err error) {
return af.file.Write(b)
}
func (af *AutoFile) Sync() error {
return af.file.Sync()
}
func (af *AutoFile) openFile() error {
file, err := os.OpenFile(af.Path, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0600)
if err != nil {


+ 41
- 5
group.go View File

@ -2,6 +2,7 @@ package autofile
import (
"bufio"
"errors"
"fmt"
"io"
"os"
@ -12,6 +13,8 @@ import (
"strings"
"sync"
"time"
. "github.com/tendermint/go-common"
)
/*
@ -56,6 +59,9 @@ type Group struct {
totalSizeLimit int64
minIndex int // Includes head
maxIndex int // Includes head, where Head will move to
// TODO: When we start deleting files, we need to start tracking GroupReaders
// and their dependencies.
}
func OpenGroup(head *AutoFile) (g *Group, err error) {
@ -183,10 +189,10 @@ func (g *Group) NewReader(index int) (*GroupReader, error) {
// Returns -1 if line comes after, 0 if found, 1 if line comes before.
type SearchFunc func(line string) (int, error)
// Searches for the right file in Group,
// then returns a GroupReader to start streaming lines
// Returns true if an exact match was found, otherwise returns
// the next greater line that starts with prefix.
// Searches for the right file in Group, then returns a GroupReader to start
// streaming lines.
// Returns true if an exact match was found, otherwise returns the next greater
// line that starts with prefix.
// CONTRACT: Caller must close the returned GroupReader
func (g *Group) Search(prefix string, cmp SearchFunc) (*GroupReader, bool, error) {
g.mtx.Lock()
@ -301,7 +307,8 @@ func scanUntil(r *GroupReader, prefix string, cmp SearchFunc) (bool, error) {
}
}
// Searches for the last line in Group with prefix.
// Searches backwards for the last line in Group with prefix.
// Scans each file forward until the end to find the last match.
func (g *Group) FindLast(prefix string) (match string, found bool, err error) {
g.mtx.Lock()
minIndex, maxIndex := g.minIndex, g.maxIndex
@ -560,3 +567,32 @@ func (gr *GroupReader) SetIndex(index int) error {
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
}
}
}

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