Golang strutil.AppendSplitN函數代碼示例

func (c *Corpus) mergeFileInfoRow(k, v []byte) error {
	// fileinfo|sha1-579f7f246bd420d486ddeb0dadbb256cfaf8bf6b" "5|some-stuff.txt|"
	pipe := bytes.IndexByte(k, '|')
	if pipe < 0 {
		return fmt.Errorf("unexpected fileinfo key %q", k)
	}
	br, ok := blob.ParseBytes(k[pipe+1:])
	if !ok {
		return fmt.Errorf("unexpected fileinfo blobref in key %q", k)
	}

	// TODO: could at least use strutil.ParseUintBytes to not stringify and retain
	// the length bytes of v.
	c.ss = strutil.AppendSplitN(c.ss[:0], string(v), "|", 3)
	if len(c.ss) != 3 {
		return fmt.Errorf("unexpected fileinfo value %q", k)
	}
	size, err := strconv.ParseInt(c.ss[0], 10, 64)
	if err != nil {
		return fmt.Errorf("unexpected fileinfo value %q", k)
	}
	c.mutateFileInfo(br, func(fi *camtypes.FileInfo) {
		fi.Size = size
		fi.FileName = c.str(urld(c.ss[1]))
		fi.MIMEType = c.str(urld(c.ss[2]))
	})
	return nil
}

func kvClaim(k, v string, blobParse func(string) (blob.Ref, bool)) (c camtypes.Claim, ok bool) {
	const nKeyPart = 5
	const nValPart = 4
	var keya [nKeyPart]string
	var vala [nValPart]string
	keyPart := strutil.AppendSplitN(keya[:0], k, "|", -1)
	valPart := strutil.AppendSplitN(vala[:0], v, "|", -1)
	if len(keyPart) < nKeyPart || len(valPart) < nValPart {
		return
	}
	signerRef, ok := blobParse(valPart[3])
	if !ok {
		return
	}
	permaNode, ok := blobParse(keyPart[1])
	if !ok {
		return
	}
	claimRef, ok := blobParse(keyPart[4])
	if !ok {
		return
	}
	date, err := time.Parse(time.RFC3339, keyPart[3])
	if err != nil {
		return
	}
	return camtypes.Claim{
		BlobRef:   claimRef,
		Signer:    signerRef,
		Permanode: permaNode,
		Date:      date,
		Type:      urld(valPart[0]),
		Attr:      urld(valPart[1]),
		Value:     urld(valPart[2]),
	}, true
}

func (c *Corpus) mergeFileTimesRow(k, v []byte) error {
	if len(v) == 0 {
		return nil
	}
	// "filetimes|sha1-579f7f246bd420d486ddeb0dadbb256cfaf8bf6b" "1970-01-01T00%3A02%3A03Z"
	pipe := bytes.IndexByte(k, '|')
	if pipe < 0 {
		return fmt.Errorf("unexpected fileinfo key %q", k)
	}
	br, ok := blob.ParseBytes(k[pipe+1:])
	if !ok {
		return fmt.Errorf("unexpected filetimes blobref in key %q", k)
	}
	c.ss = strutil.AppendSplitN(c.ss[:0], string(v), ",", -1)
	times := c.ss
	c.mutateFileInfo(br, func(fi *camtypes.FileInfo) {
		updateFileInfoTimes(fi, times)
	})
	return nil
}

// fixMissingWholeRef appends the wholeRef to all the keyFileInfo rows values. It should
// only be called to upgrade a version 4 index schema to version 5.
func (x *Index) fixMissingWholeRef(fetcher blob.Fetcher) (err error) {
	// We did that check from the caller, but double-check again to prevent from misuse
	// of that function.
	if x.schemaVersion() != 4 || requiredSchemaVersion != 5 {
		panic("fixMissingWholeRef should only be used when upgrading from v4 to v5 of the index schema")
	}
	log.Println("index: fixing the missing wholeRef in the fileInfo rows...")
	defer func() {
		if err != nil {
			log.Printf("index: fixing the fileInfo rows failed: %v", err)
			return
		}
		log.Print("index: successfully fixed wholeRef in FileInfo rows.")
	}()

	// first build a reverted keyWholeToFileRef map, so we can get the wholeRef from the fileRef easily.
	fileRefToWholeRef := make(map[blob.Ref]blob.Ref)
	it := x.queryPrefix(keyWholeToFileRef)
	var keyA [3]string
	for it.Next() {
		keyPart := strutil.AppendSplitN(keyA[:0], it.Key(), "|", 3)
		if len(keyPart) != 3 {
			return fmt.Errorf("bogus keyWholeToFileRef key: got %q, wanted \"wholetofile|wholeRef|fileRef\"", it.Key())
		}
		wholeRef, ok1 := blob.Parse(keyPart[1])
		fileRef, ok2 := blob.Parse(keyPart[2])
		if !ok1 || !ok2 {
			return fmt.Errorf("bogus part in keyWholeToFileRef key: %q", it.Key())
		}
		fileRefToWholeRef[fileRef] = wholeRef
	}
	if err := it.Close(); err != nil {
		return err
	}

	// We record the mutations and set them all after the iteration because of the sqlite locking:
	// since BeginBatch takes a lock, and Find too, we would deadlock at queryPrefix if we
	// started a batch mutation before.
	mutations := make(map[string]string)
	keyPrefix := keyFileInfo.name + "|"
	it = x.queryPrefix(keyFileInfo)
	defer it.Close()
	var valA [3]string
	for it.Next() {
		br, ok := blob.ParseBytes(it.KeyBytes()[len(keyPrefix):])
		if !ok {
			return fmt.Errorf("invalid blobRef %q", it.KeyBytes()[len(keyPrefix):])
		}
		wholeRef, ok := fileRefToWholeRef[br]
		if !ok {
			log.Printf("WARNING: wholeRef for %v not found in index. You should probably rebuild the whole index.", br)
			continue
		}
		valPart := strutil.AppendSplitN(valA[:0], it.Value(), "|", 3)
		// The old format we're fixing should be: size|filename|mimetype
		if len(valPart) != 3 {
			return fmt.Errorf("bogus keyFileInfo value: got %q, wanted \"size|filename|mimetype\"", it.Value())
		}
		size_s, filename, mimetype := valPart[0], valPart[1], urld(valPart[2])
		if strings.Contains(mimetype, "|") {
			// I think this can only happen for people migrating from a commit at least as recent as
			// 8229c1985079681a652cb65551b4e80a10d135aa, when wholeRef was introduced to keyFileInfo
			// but there was no migration code yet.
			// For the "production" migrations between 0.8 and 0.9, the index should not have any wholeRef
			// in the keyFileInfo entries. So if something goes wrong and is somehow linked to that happening,
			// I'd like to know about it, hence the logging.
			log.Printf("%v: %v already has a wholeRef, not fixing it", it.Key(), it.Value())
			continue
		}
		size, err := strconv.Atoi(size_s)
		if err != nil {
			return fmt.Errorf("bogus size in keyFileInfo value %v: %v", it.Value(), err)
		}
		mutations[keyFileInfo.Key(br)] = keyFileInfo.Val(size, filename, mimetype, wholeRef)
	}
	if err := it.Close(); err != nil {
		return err
	}
	bm := x.s.BeginBatch()
	for k, v := range mutations {
		bm.Set(k, v)
	}
	bm.Set(keySchemaVersion.name, "5")
	if err := x.s.CommitBatch(bm); err != nil {
		return err
	}
	return nil
}