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refs.go
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refs.go
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package commands
import (
"bytes"
"io"
"strings"
"sync"
context "github.com/jbenet/go-ipfs/Godeps/_workspace/src/golang.org/x/net/context"
cmds "github.com/jbenet/go-ipfs/commands"
"github.com/jbenet/go-ipfs/core"
dag "github.com/jbenet/go-ipfs/merkledag"
path "github.com/jbenet/go-ipfs/path"
u "github.com/jbenet/go-ipfs/util"
)
// KeyList is a general type for outputting lists of keys
type KeyList struct {
Keys []u.Key
}
// KeyListTextMarshaler outputs a KeyList as plaintext, one key per line
func KeyListTextMarshaler(res cmds.Response) (io.Reader, error) {
output := res.Output().(*KeyList)
var buf bytes.Buffer
for _, key := range output.Keys {
buf.WriteString(key.B58String() + "\n")
}
return &buf, nil
}
var RefsCmd = &cmds.Command{
Helptext: cmds.HelpText{
Tagline: "Lists links (references) from an object",
ShortDescription: `
Retrieves the object named by <ipfs-path> and displays the link
hashes it contains, with the following format:
<link base58 hash>
Note: list all refs recursively with -r.
`,
},
Subcommands: map[string]*cmds.Command{
"local": RefsLocalCmd,
},
Arguments: []cmds.Argument{
cmds.StringArg("ipfs-path", true, true, "Path to the object(s) to list refs from").EnableStdin(),
},
Options: []cmds.Option{
cmds.StringOption("format", "Emit edges with given format. tokens: <src> <dst> <linkname>"),
cmds.BoolOption("edges", "e", "Emit edge format: `<from> -> <to>`"),
cmds.BoolOption("unique", "u", "Omit duplicate refs from output"),
cmds.BoolOption("recursive", "r", "Recursively list links of child nodes"),
},
Run: func(req cmds.Request, res cmds.Response) {
ctx := req.Context().Context
n, err := req.Context().GetNode()
if err != nil {
res.SetError(err, cmds.ErrNormal)
return
}
unique, _, err := req.Option("unique").Bool()
if err != nil {
res.SetError(err, cmds.ErrNormal)
return
}
recursive, _, err := req.Option("recursive").Bool()
if err != nil {
res.SetError(err, cmds.ErrNormal)
return
}
edges, _, err := req.Option("edges").Bool()
if err != nil {
res.SetError(err, cmds.ErrNormal)
return
}
format, _, err := req.Option("format").String()
if err != nil {
res.SetError(err, cmds.ErrNormal)
return
}
objs, err := objectsForPaths(n, req.Arguments())
if err != nil {
res.SetError(err, cmds.ErrNormal)
return
}
piper, pipew := io.Pipe()
eptr := &ErrPassThroughReader{R: piper}
go func() {
defer pipew.Close()
rw := RefWriter{
W: pipew,
DAG: n.DAG,
Ctx: ctx,
Unique: unique,
PrintEdge: edges,
PrintFmt: format,
Recursive: recursive,
}
for _, o := range objs {
if _, err := rw.WriteRefs(o); err != nil {
eptr.SetError(err)
return
}
}
}()
res.SetOutput(eptr)
},
}
var RefsLocalCmd = &cmds.Command{
Helptext: cmds.HelpText{
Tagline: "Lists all local references",
ShortDescription: `
Displays the hashes of all local objects.
`,
},
Run: func(req cmds.Request, res cmds.Response) {
ctx := req.Context().Context
n, err := req.Context().GetNode()
if err != nil {
res.SetError(err, cmds.ErrNormal)
return
}
// todo: make async
allKeys, err := n.Blockstore.AllKeysChan(ctx)
if err != nil {
res.SetError(err, cmds.ErrNormal)
return
}
piper, pipew := io.Pipe()
eptr := &ErrPassThroughReader{R: piper}
go func() {
defer pipew.Close()
for k := range allKeys {
s := k.Pretty() + "\n"
if _, err := pipew.Write([]byte(s)); err != nil {
eptr.SetError(err)
return
}
}
}()
res.SetOutput(eptr)
},
}
func objectsForPaths(n *core.IpfsNode, paths []string) ([]*dag.Node, error) {
objects := make([]*dag.Node, len(paths))
for i, p := range paths {
o, err := n.Resolver.ResolvePath(path.Path(p))
if err != nil {
return nil, err
}
objects[i] = o
}
return objects, nil
}
// ErrPassThroughReader is a reader that may return an externally set error.
type ErrPassThroughReader struct {
R io.ReadCloser
err error
sync.RWMutex
}
func (r *ErrPassThroughReader) Error() error {
r.RLock()
defer r.RUnlock()
return r.err
}
func (r *ErrPassThroughReader) SetError(err error) {
r.Lock()
r.err = err
r.Unlock()
}
func (r *ErrPassThroughReader) Read(buf []byte) (int, error) {
err := r.Error()
if err != nil {
return 0, err
}
return r.R.Read(buf)
}
func (r *ErrPassThroughReader) Close() error {
err1 := r.R.Close()
err2 := r.Error()
if err2 != nil {
return err2
}
return err1
}
type RefWriter struct {
W io.Writer
DAG dag.DAGService
Ctx context.Context
Unique bool
Recursive bool
PrintEdge bool
PrintFmt string
seen map[u.Key]struct{}
}
// WriteRefs writes refs of the given object to the underlying writer.
func (rw *RefWriter) WriteRefs(n *dag.Node) (int, error) {
if rw.Recursive {
return rw.writeRefsRecursive(n)
} else {
return rw.writeRefsSingle(n)
}
}
func (rw *RefWriter) writeRefsRecursive(n *dag.Node) (int, error) {
nkey, err := n.Key()
if err != nil {
return 0, err
}
if rw.skip(nkey) {
return 0, nil
}
var count int
for i, ng := range rw.DAG.GetDAG(rw.Ctx, n) {
lk := u.Key(n.Links[i].Hash)
if rw.skip(lk) {
continue
}
if err := rw.WriteEdge(nkey, lk, n.Links[i].Name); err != nil {
return count, err
}
nd, err := ng.Get()
if err != nil {
return count, err
}
c, err := rw.writeRefsRecursive(nd)
count += c
if err != nil {
return count, err
}
}
return count, nil
}
func (rw *RefWriter) writeRefsSingle(n *dag.Node) (int, error) {
nkey, err := n.Key()
if err != nil {
return 0, err
}
if rw.skip(nkey) {
return 0, nil
}
count := 0
for _, l := range n.Links {
lk := u.Key(l.Hash)
if rw.skip(lk) {
continue
}
if err := rw.WriteEdge(nkey, lk, l.Name); err != nil {
return count, err
}
count++
}
return count, nil
}
// skip returns whether to skip a key
func (rw *RefWriter) skip(k u.Key) bool {
if !rw.Unique {
return false
}
if rw.seen == nil {
rw.seen = make(map[u.Key]struct{})
}
_, found := rw.seen[k]
if !found {
rw.seen[k] = struct{}{}
}
return found
}
// Write one edge
func (rw *RefWriter) WriteEdge(from, to u.Key, linkname string) error {
if rw.Ctx != nil {
select {
case <-rw.Ctx.Done(): // just in case.
return rw.Ctx.Err()
default:
}
}
var s string
switch {
case rw.PrintFmt != "":
s = rw.PrintFmt
s = strings.Replace(s, "<src>", from.Pretty(), -1)
s = strings.Replace(s, "<dst>", to.Pretty(), -1)
s = strings.Replace(s, "<linkname>", linkname, -1)
case rw.PrintEdge:
s = from.Pretty() + " -> " + to.Pretty()
default:
s += to.Pretty()
}
s += "\n"
if _, err := rw.W.Write([]byte(s)); err != nil {
return err
}
return nil
}