unixfs: fix relative seek not expanding file properly

unixfs/io/dagreader.go

@@ -210,6 +210,10 @@ func (dr *DagReader) Close() error {
 	return nil
 }
 
+func (dr *DagReader) Offset() int64 {
+	return dr.offset
+}
+
 // Seek implements io.Seeker, and will seek to a given offset in the file
 // interface matches standard unix seek
 // TODO: check if we can do relative seeks, to reduce the amount of dagreader

unixfs/mod/dagmodifier.go

@@ -6,22 +6,21 @@ import (
 	"io"
 	"os"
 
-	mh "gx/ipfs/QmYf7ng2hG5XBtJA3tN34DQ2GUN5HNksEw1rLDkmr6vGku/go-multihash"
-	proto "gx/ipfs/QmZ4Qi3GaRbjcx28Sme5eMH7RQjGkt8wHxt2a65oLaeFEV/gogo-protobuf/proto"
-	context "gx/ipfs/QmZy2y8t9zQH2a1b8q2ZSLKp17ATuJoCNxxyMFG5qFExpt/go-net/context"
-
 	key "github.com/ipfs/go-ipfs/blocks/key"
 	chunk "github.com/ipfs/go-ipfs/importer/chunk"
 	help "github.com/ipfs/go-ipfs/importer/helpers"
 	trickle "github.com/ipfs/go-ipfs/importer/trickle"
 	mdag "github.com/ipfs/go-ipfs/merkledag"
 	ft "github.com/ipfs/go-ipfs/unixfs"
 	uio "github.com/ipfs/go-ipfs/unixfs/io"
+
 	logging "gx/ipfs/QmNQynaz7qfriSUJkiEZUrm2Wen1u3Kj9goZzWtrPyu7XR/go-log"
+	mh "gx/ipfs/QmYf7ng2hG5XBtJA3tN34DQ2GUN5HNksEw1rLDkmr6vGku/go-multihash"
+	proto "gx/ipfs/QmZ4Qi3GaRbjcx28Sme5eMH7RQjGkt8wHxt2a65oLaeFEV/gogo-protobuf/proto"
+	context "gx/ipfs/QmZy2y8t9zQH2a1b8q2ZSLKp17ATuJoCNxxyMFG5qFExpt/go-net/context"
 )
 
 var ErrSeekFail = errors.New("failed to seek properly")
-var ErrSeekEndNotImpl = errors.New("SEEK_END currently not implemented")
 var ErrUnrecognizedWhence = errors.New("unrecognized whence")
 
 // 2MB
@@ -378,8 +377,8 @@ func (dm *DagModifier) Seek(offset int64, whence int) (int64, error) {
 		return 0, ErrUnrecognizedWhence
 	}
 
-	if offset > fisize {
-		if err := dm.expandSparse(offset - fisize); err != nil {
+	if int64(newoffset) > fisize {
+		if err := dm.expandSparse(int64(newoffset) - fisize); err != nil {
 			return 0, err
 		}
 	}

unixfs/mod/dagmodifier_test.go

@@ -17,10 +17,10 @@ import (
 	mdag "github.com/ipfs/go-ipfs/merkledag"
 	ft "github.com/ipfs/go-ipfs/unixfs"
 	uio "github.com/ipfs/go-ipfs/unixfs/io"
-	"gx/ipfs/QmTxLSvdhwg68WJimdS6icLPhZi28aTp6b7uihC2Yb47Xk/go-datastore/sync"
-	u "gx/ipfs/QmZNVWh8LLjAavuQ2JXuFmuYH3C11xo988vSgp7UQrTRj1/go-ipfs-util"
 
 	ds "gx/ipfs/QmTxLSvdhwg68WJimdS6icLPhZi28aTp6b7uihC2Yb47Xk/go-datastore"
+	"gx/ipfs/QmTxLSvdhwg68WJimdS6icLPhZi28aTp6b7uihC2Yb47Xk/go-datastore/sync"
+	u "gx/ipfs/QmZNVWh8LLjAavuQ2JXuFmuYH3C11xo988vSgp7UQrTRj1/go-ipfs-util"
 	context "gx/ipfs/QmZy2y8t9zQH2a1b8q2ZSLKp17ATuJoCNxxyMFG5qFExpt/go-net/context"
 )
 
@@ -548,6 +548,151 @@ func TestSeekPastEndWrite(t *testing.T) {
 	}
 }
 
+func TestRelativeSeek(t *testing.T) {
+	dserv := getMockDagServ(t)
+	_, n := getNode(t, dserv, 0)
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	dagmod, err := NewDagModifier(ctx, n, dserv, sizeSplitterGen(512))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for i := 0; i < 64; i++ {
+		dagmod.Write([]byte{byte(i)})
+		if _, err := dagmod.Seek(1, os.SEEK_CUR); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	out, err := ioutil.ReadAll(dagmod)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for i, v := range out {
+		if v != 0 && i/2 != int(v) {
+			t.Errorf("expected %d, at index %d, got %d", i/2, i, v)
+		}
+	}
+}
+
+func TestInvalidSeek(t *testing.T) {
+	dserv := getMockDagServ(t)
+
+	_, n := getNode(t, dserv, 0)
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	dagmod, err := NewDagModifier(ctx, n, dserv, sizeSplitterGen(512))
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = dagmod.Seek(10, -10)
+
+	if err != ErrUnrecognizedWhence {
+		t.Fatal(err)
+	}
+}
+
+func TestEndSeek(t *testing.T) {
+	dserv := getMockDagServ(t)
+
+	_, n := getNode(t, dserv, 0)
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	dagmod, err := NewDagModifier(ctx, n, dserv, sizeSplitterGen(512))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = dagmod.Write(make([]byte, 100))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	offset, err := dagmod.Seek(0, os.SEEK_CUR)
+	if offset != 100 {
+		t.Fatal("expected the relative seek 0 to return current location")
+	}
+
+	offset, err = dagmod.Seek(0, os.SEEK_SET)
+	if offset != 0 {
+		t.Fatal("expected the absolute seek to set offset at 0")
+	}
+
+	offset, err = dagmod.Seek(0, os.SEEK_END)
+	if offset != 100 {
+		t.Fatal("expected the end seek to set offset at end")
+	}
+}
+
+func TestReadAndSeek(t *testing.T) {
+	dserv := getMockDagServ(t)
+
+	_, n := getNode(t, dserv, 0)
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	dagmod, err := NewDagModifier(ctx, n, dserv, sizeSplitterGen(512))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	writeBuf := []byte{0, 1, 2, 3, 4, 5, 6, 7}
+	dagmod.Write(writeBuf)
+
+	readBuf := make([]byte, 4)
+	offset, err := dagmod.Seek(0, os.SEEK_SET)
+	if offset != 0 {
+		t.Fatal("expected offset to be 0")
+	}
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// read 0,1,2,3
+	c, err := dagmod.Read(readBuf)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if c != 4 {
+		t.Fatalf("expected length of 4 got %d", c)
+	}
+
+	for i := byte(0); i < 4; i++ {
+		if readBuf[i] != i {
+			t.Fatalf("wrong value %d [at index %d]", readBuf[i], i)
+		}
+	}
+
+	// skip 4
+	_, err = dagmod.Seek(1, os.SEEK_CUR)
+	if err != nil {
+		t.Fatalf("error: %s, offset %d, reader offset %d", err, dagmod.curWrOff, dagmod.read.Offset())
+	}
+
+	//read 5,6,7
+	readBuf = make([]byte, 3)
+	c, err = dagmod.Read(readBuf)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if c != 3 {
+		t.Fatalf("expected length of 3 got %d", c)
+	}
+
+	for i := byte(0); i < 3; i++ {
+		if readBuf[i] != i+5 {
+			t.Fatalf("wrong value %d [at index %d]", readBuf[i], i)
+		}
+
+	}
+
+}
+
 func BenchmarkDagmodWrite(b *testing.B) {
 	b.StopTimer()
 	dserv := getMockDagServ(b)