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minio/fs-dir-common.go

229 lines
7.0 KiB

/*
* Minio Cloud Storage, (C) 2016 Minio, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package main
import (
"os"
"path"
"sort"
"strings"
"time"
)
// fsDirent carries directory entries.
type fsDirent struct {
name string
modTime time.Time // On Solaris and older unix distros this is empty.
size int64 // On Solaris and older unix distros this is empty.
mode os.FileMode
}
// IsDir - returns true if fsDirent is a directory
func (ent fsDirent) IsDir() bool {
return ent.mode.IsDir()
}
// IsSymlink - returns true if fsDirent is a symbolic link
func (ent fsDirent) IsSymlink() bool {
return ent.mode&os.ModeSymlink == os.ModeSymlink
}
// IsRegular - returns true if fsDirent is a regular file
func (ent fsDirent) IsRegular() bool {
return ent.mode.IsRegular()
}
// byDirentName is a collection satisfying sort.Interface.
type byDirentName []fsDirent
func (d byDirentName) Len() int { return len(d) }
func (d byDirentName) Swap(i, j int) { d[i], d[j] = d[j], d[i] }
func (d byDirentName) Less(i, j int) bool { return d[i].name < d[j].name }
// Using sort.Search() internally to jump to the file entry containing
// the prefix.
func searchDirents(dirents []fsDirent, x string) int {
processFunc := func(i int) bool {
return dirents[i].name >= x
}
return sort.Search(len(dirents), processFunc)
}
// Tree walk result carries results of tree walking.
type treeWalkResult struct {
fileInfo FileInfo
err error
end bool
}
// Tree walk notify carries a channel which notifies tree walk
// results, additionally it also carries information if treeWalk
// should be timedOut.
type treeWalker struct {
ch <-chan treeWalkResult
timedOut bool
}
// treeWalk walks FS directory tree recursively pushing fileInfo into the channel as and when it encounters files.
func treeWalk(bucketDir, prefixDir, entryPrefixMatch, marker string, recursive bool, send func(treeWalkResult) bool, count *int) bool {
// Example:
// if prefixDir="one/two/three/" and marker="four/five.txt" treeWalk is recursively
// called with prefixDir="one/two/three/four/" and marker="five.txt"
// Convert dirent to FileInfo
direntToFileInfo := func(dirent fsDirent) (FileInfo, error) {
fileInfo := FileInfo{}
// Convert to full object name.
fileInfo.Name = path.Join(prefixDir, dirent.name)
if dirent.modTime.IsZero() && dirent.size == 0 {
// ModifiedTime and Size are zero, Stat() and figure out
// the actual values that need to be set.
fi, err := os.Stat(path.Join(bucketDir, prefixDir, dirent.name))
if err != nil {
return FileInfo{}, err
}
// Fill size and modtime.
fileInfo.ModTime = fi.ModTime()
fileInfo.Size = fi.Size()
fileInfo.Mode = fi.Mode()
} else {
// If ModTime or Size are set then use them
// without attempting another Stat operation.
fileInfo.ModTime = dirent.modTime
fileInfo.Size = dirent.size
fileInfo.Mode = dirent.mode
}
if fileInfo.Mode.IsDir() {
// Add os.PathSeparator suffix again for directories as
// filepath.Join would have removed it.
fileInfo.Size = 0
fileInfo.Name += string(os.PathSeparator)
}
return fileInfo, nil
}
var markerBase, markerDir string
if marker != "" {
// Ex: if marker="four/five.txt", markerDir="four/" markerBase="five.txt"
markerSplit := strings.SplitN(marker, slashSeparator, 2)
markerDir = markerSplit[0]
if len(markerSplit) == 2 {
markerDir += slashSeparator
markerBase = markerSplit[1]
}
}
// Entry prefix match function.
prefixMatchFn := func(dirent fsDirent) bool {
if dirent.IsDir() || dirent.IsRegular() {
// Does dirent name has reserved prefixes or suffixes.
hasReserved := hasReservedPrefix(dirent.name) || hasReservedSuffix(dirent.name)
// All dirents which match prefix and do not have reserved
// keywords in them are valid entries.
return strings.HasPrefix(dirent.name, entryPrefixMatch) && !hasReserved && isValidPath(dirent.name)
}
return false
}
// scandir returns entries that begins with entryPrefixMatch
dirents, err := scandir(path.Join(bucketDir, prefixDir), prefixMatchFn, true)
if err != nil {
send(treeWalkResult{err: err})
return false
}
// example:
// If markerDir="four/" searchDirents() returns the index of "four/" in the sorted
// dirents list. We skip all the dirent entries till "four/"
dirents = dirents[searchDirents(dirents, markerDir):]
*count += len(dirents)
for i, dirent := range dirents {
if i == 0 && markerDir == dirent.name && !dirent.IsDir() {
// If the first entry is not a directory
// we need to skip this entry.
*count--
continue
}
if dirent.IsDir() && recursive {
// If the entry is a directory, we will need recurse into it.
markerArg := ""
if dirent.name == markerDir {
// We need to pass "five.txt" as marker only if we are
// recursing into "four/"
markerArg = markerBase
}
*count--
if !treeWalk(bucketDir, path.Join(prefixDir, dirent.name), "", markerArg, recursive, send, count) {
return false
}
continue
}
fileInfo, err := direntToFileInfo(dirent)
if err != nil {
send(treeWalkResult{err: err})
return false
}
*count--
if !send(treeWalkResult{fileInfo: fileInfo}) {
return false
}
}
return true
}
// Initiate a new treeWalk in a goroutine.
func startTreeWalk(fsPath, bucket, prefix, marker string, recursive bool) *treeWalker {
// Example 1
// If prefix is "one/two/three/" and marker is "one/two/three/four/five.txt"
// treeWalk is called with prefixDir="one/two/three/" and marker="four/five.txt"
// and entryPrefixMatch=""
// Example 2
// if prefix is "one/two/th" and marker is "one/two/three/four/five.txt"
// treeWalk is called with prefixDir="one/two/" and marker="three/four/five.txt"
// and entryPrefixMatch="th"
ch := make(chan treeWalkResult, fsListLimit)
walkNotify := treeWalker{ch: ch}
entryPrefixMatch := prefix
prefixDir := ""
lastIndex := strings.LastIndex(prefix, slashSeparator)
if lastIndex != -1 {
entryPrefixMatch = prefix[lastIndex+1:]
prefixDir = prefix[:lastIndex+1]
}
count := 0
marker = strings.TrimPrefix(marker, prefixDir)
go func() {
defer close(ch)
send := func(walkResult treeWalkResult) bool {
if count == 0 {
walkResult.end = true
}
timer := time.After(time.Second * 60)
select {
case ch <- walkResult:
return true
case <-timer:
walkNotify.timedOut = true
return false
}
}
bucketDir := path.Join(fsPath, bucket)
treeWalk(bucketDir, prefixDir, entryPrefixMatch, marker, recursive, send, &count)
}()
return &walkNotify
}