moved util/ctx to github.com/jbenet/go-context

License: MIT
Signed-off-by: Juan Batiz-Benet <juan@benet.ai>

Godeps/Godeps.json

@@ -15,11 +15,6 @@
 			"Rev": "75cd24fc2f2c2a2088577d12123ddee5f54e0675"
 		},
 		{
-			"ImportPath": "code.google.com/p/goprotobuf/proto",
-			"Comment": "go.r60-152",
-			"Rev": "36be16571e14f67e114bb0af619e5de2c1591679"
-		},
-		{
 			"ImportPath": "github.com/ActiveState/tail",
 			"Rev": "068b72961a6bc5b4a82cf4fc14ccc724c0cfa73a"
 		},
@@ -138,6 +133,14 @@
 			"Rev": "6237cf65f3a6f7111cd8a42be3590df99a66bc7d"
 		},
 		{
+			"ImportPath": "github.com/jbenet/go-context/frac",
+			"Rev": "d14ea06fba99483203c19d92cfcd13ebe73135f4"
+		},
+		{
+			"ImportPath": "github.com/jbenet/go-context/io",
+			"Rev": "d14ea06fba99483203c19d92cfcd13ebe73135f4"
+		},
+		{
 			"ImportPath": "github.com/jbenet/go-datastore",
 			"Rev": "7d6acaf7c0164c335f2ca4100f8fe30a7e2943dd"
 		},

Godeps/_workspace/src/github.com/jbenet/go-context/frac/fracctx.go

+// Package ctxext provides multiple useful context constructors.
+package ctxext
+
+import (
+	"time"
+
+	context "github.com/ipfs/go-ipfs/Godeps/_workspace/src/golang.org/x/net/context"
+)
+
+// WithDeadlineFraction returns a Context with a fraction of the
+// original context's timeout. This is useful in sequential pipelines
+// of work, where one might try options and fall back to others
+// depending on the time available, or failure to respond. For example:
+//
+//  // getPicture returns a picture from our encrypted database
+//  // we have a pipeline of multiple steps. we need to:
+//  // - get the data from a database
+//  // - decrypt it
+//  // - apply many transforms
+//  //
+//  // we **know** that each step takes increasingly more time.
+//  // The transforms are much more expensive than decryption, and
+//  // decryption is more expensive than the database lookup.
+//  // If our database takes too long (i.e. >0.2 of available time),
+//  // there's no use in continuing.
+//  func getPicture(ctx context.Context, key string) ([]byte, error) {
+//    // fractional timeout contexts to the rescue!
+//
+//    // try the database with 0.2 of remaining time.
+//    ctx1, _ := ctxext.WithDeadlineFraction(ctx, 0.2)
+//    val, err := db.Get(ctx1, key)
+//    if err != nil {
+//      return nil, err
+//    }
+//
+//    // try decryption with 0.3 of remaining time.
+//    ctx2, _ := ctxext.WithDeadlineFraction(ctx, 0.3)
+//    if val, err = decryptor.Decrypt(ctx2, val); err != nil {
+//      return nil, err
+//    }
+//
+//    // try transforms with all remaining time. hopefully it's enough!
+//    return transformer.Transform(ctx, val)
+//  }
+//
+//
+func WithDeadlineFraction(ctx context.Context, fraction float64) (
+	context.Context, context.CancelFunc) {
+
+	d, found := ctx.Deadline()
+	if !found { // no deadline
+		return context.WithCancel(ctx)
+	}
+
+	left := d.Sub(time.Now())
+	if left < 0 { // already passed...
+		return context.WithCancel(ctx)
+	}
+
+	left = time.Duration(float64(left) * fraction)
+	return context.WithTimeout(ctx, left)
+}

util/ctx/fracctx_test.go → Godeps/_workspace/src/github.com/jbenet/go-context/frac/fracctx_test.go

-package ctxutil
+package ctxext
 
 import (
+	"os"
 	"testing"
 	"time"
 
-	travis "github.com/ipfs/go-ipfs/util/testutil/ci/travis"
-
 	context "github.com/ipfs/go-ipfs/Godeps/_workspace/src/golang.org/x/net/context"
 )
 
 // this test is on the context tool itself, not our stuff. it's for sanity on ours.
 func TestDeadline(t *testing.T) {
-	if travis.IsRunning() {
+	if os.Getenv("TRAVIS") == "true" {
 		t.Skip("timeouts don't work reliably on travis")
 	}
 
@@ -43,7 +42,7 @@ func TestDeadlineFractionForever(t *testing.T) {
 }
 
 func TestDeadlineFractionHalf(t *testing.T) {
-	if travis.IsRunning() {
+	if os.Getenv("TRAVIS") == "true" {
 		t.Skip("timeouts don't work reliably on travis")
 	}
 

util/ctx/ctxio.go → Godeps/_workspace/src/github.com/jbenet/go-context/io/ctxio.go

-package ctxutil
+// Package ctxio provides io.Reader and io.Writer wrappers that
+// respect context.Contexts. Use these at the interface between
+// your context code and your io.
+//
+// WARNING: read the code. see how writes and reads will continue
+// until you cancel the io. Maybe this package should provide
+// versions of io.ReadCloser and io.WriteCloser that automatically
+// call .Close when the context expires. But for now -- since in my
+// use cases I have long-lived connections with ephemeral io wrappers
+// -- this has yet to be a need.
+package ctxio
 
 import (
 	"io"

util/ctx/ctxio_test.go → Godeps/_workspace/src/github.com/jbenet/go-context/io/ctxio_test.go

-package ctxutil
+package ctxio
 
 import (
 	"bytes"
@@ -49,8 +49,8 @@ func TestReader(t *testing.T) {
 }
 
 func TestWriter(t *testing.T) {
-	buf := new(bytes.Buffer)
-	w := NewWriter(context.Background(), buf)
+	var buf bytes.Buffer
+	w := NewWriter(context.Background(), &buf)
 
 	// write three
 	n, err := w.Write([]byte("abc"))

diagnostics/diag.go

@@ -13,15 +13,14 @@ import (
 
 	ggio "github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/gogo/protobuf/io"
 	proto "github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/gogo/protobuf/proto"
+	ctxio "github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-context/io"
 	context "github.com/ipfs/go-ipfs/Godeps/_workspace/src/golang.org/x/net/context"
-
 	pb "github.com/ipfs/go-ipfs/diagnostics/pb"
 	host "github.com/ipfs/go-ipfs/p2p/host"
 	inet "github.com/ipfs/go-ipfs/p2p/net"
 	peer "github.com/ipfs/go-ipfs/p2p/peer"
 	protocol "github.com/ipfs/go-ipfs/p2p/protocol"
 	util "github.com/ipfs/go-ipfs/util"
-	ctxutil "github.com/ipfs/go-ipfs/util/ctx"
 )
 
 var log = util.Logger("diagnostics")
@@ -209,8 +208,8 @@ func (d *Diagnostics) getDiagnosticFromPeer(ctx context.Context, p peer.ID, pmes
 		return nil, err
 	}
 
-	cr := ctxutil.NewReader(ctx, s) // ok to use. we defer close stream in this func
-	cw := ctxutil.NewWriter(ctx, s) // ok to use. we defer close stream in this func
+	cr := ctxio.NewReader(ctx, s) // ok to use. we defer close stream in this func
+	cw := ctxio.NewWriter(ctx, s) // ok to use. we defer close stream in this func
 	r := ggio.NewDelimitedReader(cr, inet.MessageSizeMax)
 	w := ggio.NewDelimitedWriter(cw)
 
@@ -267,8 +266,8 @@ func newMessage(diagID string) *pb.Message {
 
 func (d *Diagnostics) HandleMessage(ctx context.Context, s inet.Stream) error {
 
-	cr := ctxutil.NewReader(ctx, s)
-	cw := ctxutil.NewWriter(ctx, s)
+	cr := ctxio.NewReader(ctx, s)
+	cw := ctxio.NewWriter(ctx, s)
 	r := ggio.NewDelimitedReader(cr, inet.MessageSizeMax) // maxsize
 	w := ggio.NewDelimitedWriter(cw)
 

routing/dht/dht_net.go

@@ -4,13 +4,12 @@ import (
 	"errors"
 	"time"
 
+	ggio "github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/gogo/protobuf/io"
+	ctxio "github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-context/io"
+	context "github.com/ipfs/go-ipfs/Godeps/_workspace/src/golang.org/x/net/context"
 	inet "github.com/ipfs/go-ipfs/p2p/net"
 	peer "github.com/ipfs/go-ipfs/p2p/peer"
 	pb "github.com/ipfs/go-ipfs/routing/dht/pb"
-	ctxutil "github.com/ipfs/go-ipfs/util/ctx"
-
-	ggio "github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/gogo/protobuf/io"
-	context "github.com/ipfs/go-ipfs/Godeps/_workspace/src/golang.org/x/net/context"
 )
 
 // handleNewStream implements the inet.StreamHandler
@@ -22,8 +21,8 @@ func (dht *IpfsDHT) handleNewMessage(s inet.Stream) {
 	defer s.Close()
 
 	ctx := dht.Context()
-	cr := ctxutil.NewReader(ctx, s) // ok to use. we defer close stream in this func
-	cw := ctxutil.NewWriter(ctx, s) // ok to use. we defer close stream in this func
+	cr := ctxio.NewReader(ctx, s) // ok to use. we defer close stream in this func
+	cw := ctxio.NewWriter(ctx, s) // ok to use. we defer close stream in this func
 	r := ggio.NewDelimitedReader(cr, inet.MessageSizeMax)
 	w := ggio.NewDelimitedWriter(cw)
 	mPeer := s.Conn().RemotePeer()
@@ -78,8 +77,8 @@ func (dht *IpfsDHT) sendRequest(ctx context.Context, p peer.ID, pmes *pb.Message
 	}
 	defer s.Close()
 
-	cr := ctxutil.NewReader(ctx, s) // ok to use. we defer close stream in this func
-	cw := ctxutil.NewWriter(ctx, s) // ok to use. we defer close stream in this func
+	cr := ctxio.NewReader(ctx, s) // ok to use. we defer close stream in this func
+	cw := ctxio.NewWriter(ctx, s) // ok to use. we defer close stream in this func
 	r := ggio.NewDelimitedReader(cr, inet.MessageSizeMax)
 	w := ggio.NewDelimitedWriter(cw)
 
@@ -116,7 +115,7 @@ func (dht *IpfsDHT) sendMessage(ctx context.Context, p peer.ID, pmes *pb.Message
 	}
 	defer s.Close()
 
-	cw := ctxutil.NewWriter(ctx, s) // ok to use. we defer close stream in this func
+	cw := ctxio.NewWriter(ctx, s) // ok to use. we defer close stream in this func
 	w := ggio.NewDelimitedWriter(cw)
 
 	if err := w.WriteMsg(pmes); err != nil {

routing/dht/records.go

@@ -3,13 +3,13 @@ package dht
 import (
 	"fmt"
 
+	ctxfrac "github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-context/frac"
 	"github.com/ipfs/go-ipfs/Godeps/_workspace/src/golang.org/x/net/context"
 	ci "github.com/ipfs/go-ipfs/p2p/crypto"
 	peer "github.com/ipfs/go-ipfs/p2p/peer"
 	routing "github.com/ipfs/go-ipfs/routing"
 	pb "github.com/ipfs/go-ipfs/routing/dht/pb"
 	record "github.com/ipfs/go-ipfs/routing/record"
-	ctxutil "github.com/ipfs/go-ipfs/util/ctx"
 )
 
 func (dht *IpfsDHT) GetPublicKey(ctx context.Context, p peer.ID) (ci.PubKey, error) {
@@ -22,7 +22,7 @@ func (dht *IpfsDHT) GetPublicKey(ctx context.Context, p peer.ID) (ci.PubKey, err
 	}
 
 	// ok, try the node itself. if they're overwhelmed or slow we can move on.
-	ctxT, cancelFunc := ctxutil.WithDeadlineFraction(ctx, 0.3)
+	ctxT, cancelFunc := ctxfrac.WithDeadlineFraction(ctx, 0.3)
 	defer cancelFunc()
 	if pk, err := dht.getPublicKeyFromNode(ctx, p); err == nil {
 		err := dht.peerstore.AddPubKey(p, pk)

util/ctx/fracctx.go

-package ctxutil
-
-import (
-	"time"
-
-	context "github.com/ipfs/go-ipfs/Godeps/_workspace/src/golang.org/x/net/context"
-)
-
-func WithDeadlineFraction(ctx context.Context, fraction float64) (context.Context, context.CancelFunc) {
-	d, found := ctx.Deadline()
-	if !found { // no deadline
-		return context.WithCancel(ctx)
-	}
-
-	left := d.Sub(time.Now())
-	if left < 0 { // already passed...
-		return context.WithCancel(ctx)
-	}
-
-	left = time.Duration(float64(left) * fraction)
-	return context.WithTimeout(ctx, left)
-}