archive/zip: lazy load file data descriptor

tinti · tinti · commit 3fbc23aaf9e9 · 2021-10-03T18:26:54.000-03:00
Fixes golang#48374 Signed-off-by: Vinicius Tinti <viniciustinti@gmail.com>
diff --git a/src/archive/zip/reader.go b/src/archive/zip/reader.go
@@ -125,7 +125,6 @@ func (z *Reader) init(r io.ReaderAt, size int64) error {
 		if err != nil {
 			return err
 		}
-		f.readDataDescriptor()
 		z.File = append(z.File, f)
 	}
 	if uint16(len(z.File)) != uint16(end.directoryRecords) { // only compare 16 bits here
@@ -789,6 +788,8 @@ func (r *Reader) Open(name string) (fs.File, error) {
 	if e.isDir {
 		return &openDir{e, r.openReadDir(name), 0}, nil
 	}
+
+	e.file.readDataDescriptor()
 	rc, err := e.file.Open()
 	if err != nil {
 		return nil, err

Original file line number	Diff line number	Diff line change
`@@ -125,7 +125,6 @@ func (z *Reader) init(r io.ReaderAt, size int64) error {`
`125`	`125`	`if err != nil {`
`126`	`126`	`return err`
`127`	`127`	`}`
`128`		`- f.readDataDescriptor()`
`129`	`128`	`z.File = append(z.File, f)`
`130`	`129`	`}`
`131`	`130`	`if uint16(len(z.File)) != uint16(end.directoryRecords) { // only compare 16 bits here`
`@@ -789,6 +788,8 @@ func (r *Reader) Open(name string) (fs.File, error) {`
`789`	`788`	`if e.isDir {`
`790`	`789`	`return &openDir{e, r.openReadDir(name), 0}, nil`
`791`	`790`	`}`
	`791`	`+`
	`792`	`+ e.file.readDataDescriptor()`
`792`	`793`	`rc, err := e.file.Open()`
`793`	`794`	`if err != nil {`
`794`	`795`	`return nil, err`