vfs/version.go

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/*
* Copyright (c) 2015 Alex Yatskov <alex@foosoft.net>
* Author: Alex Yatskov <alex@foosoft.net>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
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package main
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import (
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"bazil.org/fuse/fs"
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"fmt"
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"io/ioutil"
"os"
"path/filepath"
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"regexp"
"strconv"
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"strings"
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"time"
)
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type version struct {
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base string
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parent *version
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timestamp time.Time
meta *versionMetadata
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root *versionedDir
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inodeAloc InodeAllocator
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}
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type InodeAllocator interface {
AllocInode() uint64
}
func newVersion(base string, allocator InodeAllocator, parent *version) (*version, error) {
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re, err := regexp.Compile(`/vfs_([0-9a-f])$`)
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if err != nil {
return nil, err
}
matches := re.FindStringSubmatch(base)
if len(matches) < 2 {
return nil, fmt.Errorf("invalid version identifier for %s", base)
}
timeval, err := strconv.ParseInt(matches[1], 16, 64)
if err != nil {
return nil, err
}
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ver := &version{
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base: base,
parent: parent,
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timestamp: time.Unix(timeval, 0),
inodeAloc: allocator}
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ver.meta, err = newVersionMetadata(ver.metadataPath())
if err != nil {
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return nil, err
}
return ver, nil
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}
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func (this *version) newVersionedNode(path string, info os.FileInfo) *versionedNode {
return &versionedNode{path, info, this}
}
func (this *version) scanDir(path string) (versionedNodeMap, error) {
var baseNodes versionedNodeMap
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if this.parent != nil {
var err error
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baseNodes, err = this.parent.scanDir(path)
if err != nil {
return nil, err
}
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this.meta.filter(baseNodes)
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}
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ownNodes := make(versionedNodeMap)
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{
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nodes, err := ioutil.ReadDir(this.rebasePath(path))
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if !os.IsNotExist(err) {
if err != nil {
return nil, err
}
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for _, node := range nodes {
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ownNodes[node.Name()] = this.newVersionedNode(filepath.Join(path, node.Name()), node)
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}
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}
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this.meta.filter(ownNodes)
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}
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if baseNodes == nil {
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return ownNodes, nil
}
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for ownName, ownNode := range ownNodes {
baseNodes[ownName] = ownNode
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}
return baseNodes, nil
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}
func (this *version) buildVerDir(dir *versionedDir) error {
nodes, err := this.scanDir(dir.node.path)
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if err != nil {
return err
}
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for name, node := range nodes {
if node.info.IsDir() {
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subDir := newVersionedDir(node, this.inodeAloc.AllocInode(), dir)
if err := this.buildVerDir(subDir); err != nil {
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return err
}
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dir.dirs[name] = subDir
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} else {
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dir.files[name] = newVersionedFile(node, this.inodeAloc.AllocInode(), dir)
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}
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}
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return nil
}
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func (this *version) resolve() error {
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node, err := os.Stat(this.rebasePath("/"))
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if err != nil {
return err
}
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this.root = newVersionedDir(
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this.newVersionedNode("/", node),
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this.inodeAloc.AllocInode(),
nil)
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return this.buildVerDir(this.root)
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}
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func (this *version) metadataPath() string {
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return filepath.Join(this.base, "meta.json")
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}
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func (this *version) rebasePath(paths ...string) string {
combined := append([]string{this.base, "root"}, paths...)
return filepath.Join(combined...)
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}
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func (this *version) Root() (fs.Node, error) {
return this.root, nil
}
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func (this *version) dump(root *versionedDir, depth int) {
indent := strings.Repeat("\t", depth)
for name, dir := range root.dirs {
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fmt.Printf("%s+ %s [%s@%d]\n", indent, name, dir.node.path, dir.node.ver.timestamp.Unix())
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this.dump(dir, depth+1)
}
for name, file := range root.files {
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fmt.Printf("%s- %s [%s@%d]\n", indent, name, file.node.path, file.node.ver.timestamp.Unix())
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}
}
func (this *version) dumpRoot() {
this.dump(this.root, 0)
}