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tar: flatten the pseudo-tree only after readHeaders() is done

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Flattening within the readHeaders() function call was problematic
because readHeaders() is called as a goroutine; thus, as the
main program was calling `tdh.writeTo(os.Stdout)`, readHeaders() was
still in the process of flattening the tree structure. To get around this,
we now call flatten in ts.Hierarchy(), such that only when the main program
is ready to retrieve a "valid" DirectoryHierarchy from the archive, should
we flatten the tree.

Signed-off-by: Stephen Chung <schung@redhat.com>
This commit is contained in:
Stephen Chung 2016-08-02 11:42:02 -04:00
parent 822f319224
commit 6a37331074
1 changed files with 16 additions and 5 deletions
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21
tar.go
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@ -2,6 +2,7 @@ package mtree
import (
"archive/tar"
"fmt"
"io"
"io/ioutil"
"os"
@ -29,11 +30,13 @@ func NewTarStreamer(r io.Reader, keywords []string) Streamer {
tarReader: tar.NewReader(pR),
keywords: keywords,
}
go ts.readHeaders() // I don't like this
go ts.readHeaders()
return ts
}
type tarStream struct {
root *Entry
creator dhCreator
pipeReader *io.PipeReader
pipeWriter *io.PipeWriter
@ -50,7 +53,7 @@ func (ts *tarStream) readHeaders() {
Raw: "# .",
Type: CommentType,
}
root := Entry{
ts.root = &Entry{
Name: ".",
Type: RelativeType,
Prev: &rootComment,
@ -67,7 +70,6 @@ func (ts *tarStream) readHeaders() {
for {
hdr, err := ts.tarReader.Next()
if err != nil {
flatten(&root, &ts.creator, ts.keywords)
ts.pipeReader.CloseWithError(err)
return
}
@ -162,12 +164,12 @@ func (ts *tarStream) readHeaders() {
}
}
if filepath.Dir(filepath.Clean(hdr.Name)) == "." {
root.Set = &s
ts.root.Set = &s
} else {
e.Set = &s
}
}
err = populateTree(&root, &e, hdr)
err = populateTree(ts.root, &e, hdr)
if err != nil {
ts.setErr(err)
}
@ -209,6 +211,7 @@ func populateTree(root, e *Entry, hdr *tar.Header) error {
}
return nil
}
// TODO: what about directory/file names with "/" in it?
dirNames := strings.Split(wd, "/")
parent := root
for _, name := range dirNames[1:] {
@ -259,6 +262,9 @@ func populateTree(root, e *Entry, hdr *tar.Header) error {
// creator: a dhCreator that helps with the '/set' keyword
// keywords: keywords specified by the user that should be evaluated
func flatten(root *Entry, creator *dhCreator, keywords []string) {
if root == nil {
return
}
if root.Prev != nil {
// root.Prev != nil implies root is a directory
creator.DH.Entries = append(creator.DH.Entries,
@ -317,6 +323,7 @@ func flatten(root *Entry, creator *dhCreator, keywords []string) {
}
creator.DH.Entries = append(creator.DH.Entries, dotEntry)
}
return
}
// filter takes in a pointer to an Entry, and returns a slice of Entry's that
@ -387,5 +394,9 @@ func (ts *tarStream) Hierarchy() (*DirectoryHierarchy, error) {
if ts.err != nil && ts.err != io.EOF {
return nil, ts.err
}
if ts.root == nil {
return nil, fmt.Errorf("root Entry not found. Nothing to flatten")
}
flatten(ts.root, &ts.creator, ts.keywords)
return ts.creator.DH, nil
}