From e1cfb6f3a909d2918155d72676dd80c956bbdf6e Mon Sep 17 00:00:00 2001
From: Gustavo Niemeyer <gustavo@niemeyer.net>
Date: Tue, 30 Aug 2011 14:33:16 -0300
Subject: [PATCH] cgo: fix GoBytes

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/4956051
---
 misc/cgo/test/Makefile     |  1 +
 misc/cgo/test/callback.go  |  2 +-
 misc/cgo/test/cgo_test.go  |  1 +
 misc/cgo/test/helpers.go   | 35 +++++++++++++++++++++++++++++++++++
 src/pkg/runtime/string.goc |  2 ++
 5 files changed, 40 insertions(+), 1 deletion(-)
 create mode 100644 misc/cgo/test/helpers.go

diff --git a/misc/cgo/test/Makefile b/misc/cgo/test/Makefile
index d4309be3c6..5617e78c37 100644
--- a/misc/cgo/test/Makefile
+++ b/misc/cgo/test/Makefile
@@ -12,6 +12,7 @@ CGOFILES=\
 	callback.go\
 	env.go\
 	exports.go\
+	helpers.go\
 	issue1222.go\
 	issue1328.go\
 	issue1560.go\
diff --git a/misc/cgo/test/callback.go b/misc/cgo/test/callback.go
index 3edee97581..d20790e875 100644
--- a/misc/cgo/test/callback.go
+++ b/misc/cgo/test/callback.go
@@ -65,7 +65,7 @@ func testCallbackPanic(t *testing.T) {
 func testCallbackPanicLoop(t *testing.T) {
 	// Make sure we don't blow out m->g0 stack.
 	for i := 0; i < 100000; i++ {
-		TestCallbackPanic(t)
+		testCallbackPanic(t)
 	}
 }
 
diff --git a/misc/cgo/test/cgo_test.go b/misc/cgo/test/cgo_test.go
index 03f02370a1..34beee69d1 100644
--- a/misc/cgo/test/cgo_test.go
+++ b/misc/cgo/test/cgo_test.go
@@ -26,5 +26,6 @@ func TestBlocking(t *testing.T)            { testBlocking(t) }
 func Test1328(t *testing.T)                { test1328(t) }
 func TestParallelSleep(t *testing.T)       { testParallelSleep(t) }
 func TestSetEnv(t *testing.T)              { testSetEnv(t) }
+func TestHelpers(t *testing.T)             { testHelpers(t) }
 
 func BenchmarkCgoCall(b *testing.B) { benchCgoCall(b) }
diff --git a/misc/cgo/test/helpers.go b/misc/cgo/test/helpers.go
new file mode 100644
index 0000000000..3a4f014225
--- /dev/null
+++ b/misc/cgo/test/helpers.go
@@ -0,0 +1,35 @@
+// Copyright 2011 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cgotest
+
+// const char *greeting = "hello, world";
+import "C"
+
+import (
+	"reflect"
+	"testing"
+	"unsafe"
+)
+
+const greeting = "hello, world"
+
+type testPair struct {
+	Name string
+	Got, Want interface{}
+}
+
+var testPairs = []testPair{
+	{"GoString", C.GoString(C.greeting), greeting},
+	{"GoStringN", C.GoStringN(C.greeting, 5), greeting[:5]},
+	{"GoBytes", C.GoBytes(unsafe.Pointer(C.greeting), 5), []byte(greeting[:5])},
+}
+
+func testHelpers(t *testing.T) {
+	for _, pair := range testPairs {
+		if !reflect.DeepEqual(pair.Got, pair.Want) {
+			t.Errorf("%s: got %#v, want %#v", pair.Got, pair.Want)
+		}
+	}
+}
diff --git a/src/pkg/runtime/string.goc b/src/pkg/runtime/string.goc
index 48bf3183b5..322706c0c4 100644
--- a/src/pkg/runtime/string.goc
+++ b/src/pkg/runtime/string.goc
@@ -80,6 +80,8 @@ runtime·gobytes(byte *p, int32 n)
 	Slice sl;
 
 	sl.array = runtime·mallocgc(n, FlagNoPointers, 1, 0);
+	sl.len = n;
+	sl.cap = n;
 	runtime·memmove(sl.array, p, n);
 	return sl;
 }