From f251b539c3fbeda8a5cde424235f737fe009986a Mon Sep 17 00:00:00 2001
From: Emmet Cassidy <ecassidy@cloudmark.com>
Date: Wed, 28 Oct 2015 09:25:11 -0700
Subject: [PATCH] added append function and a test

---
 rados/ioctx.go      | 13 +++++++++++++
 rados/rados_test.go | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)

diff --git a/rados/ioctx.go b/rados/ioctx.go
index b428c6f..27b687d 100644
--- a/rados/ioctx.go
+++ b/rados/ioctx.go
@@ -78,6 +78,19 @@ func (ioctx *IOContext) WriteFull(oid string, data []byte) error {
 	return GetRadosError(ret)
 }
 
+// Append appends len(data) bytes to the object with key oid.
+// The object is appended with the provided data. If the object exists,
+// it is atomically appended to. It returns an error, if any.
+func (ioctx *IOContext) Append(oid string, data []byte) error {
+	c_oid := C.CString(oid)
+	defer C.free(unsafe.Pointer(c_oid))
+
+	ret := C.rados_append(ioctx.ioctx, c_oid,
+		(*C.char)(unsafe.Pointer(&data[0])),
+		(C.size_t)(len(data)))
+	return GetRadosError(ret)
+}
+
 // Read reads up to len(data) bytes from the object with key oid starting at byte
 // offset offset. It returns the number of bytes read and an error, if any.
 func (ioctx *IOContext) Read(oid string, data []byte, offset uint64) (int, error) {
diff --git a/rados/rados_test.go b/rados/rados_test.go
index 051694f..b2b7c70 100644
--- a/rados/rados_test.go
+++ b/rados/rados_test.go
@@ -321,6 +321,38 @@ func TestReadWrite(t *testing.T) {
 	conn.Shutdown()
 }
 
+func TestAppend(t *testing.T) {
+	conn, _ := rados.NewConn()
+	conn.ReadDefaultConfigFile()
+	conn.Connect()
+
+	// make pool
+	pool_name := GetUUID()
+	err := conn.MakePool(pool_name)
+	assert.NoError(t, err)
+
+	pool, err := conn.OpenIOContext(pool_name)
+	assert.NoError(t, err)
+
+	bytes_accum := []byte{}
+	for _, str_in := range []string{"input", " ", "another", " ", "data"} {
+		bytes_in := []byte(str_in)
+		err = pool.Append("obj", bytes_in)
+		assert.NoError(t, err)
+
+		bytes_accum = append(bytes_accum, bytes_in...)
+		bytes_out := make([]byte, len(bytes_accum))
+		n_out, err := pool.Read("obj", bytes_out, 0)
+
+		assert.NoError(t, err)
+		assert.Equal(t, n_out, len(bytes_accum))
+		assert.Equal(t, bytes_accum, bytes_out)
+	}
+
+	pool.Destroy()
+	conn.Shutdown()
+}
+
 func TestNotFound(t *testing.T) {
 	conn, _ := rados.NewConn()
 	conn.ReadDefaultConfigFile()