rados: add support for object listing

Signed-off-by: Noah Watkins <noahwatkins@gmail.com>

ioctx.go

@@ -157,3 +157,32 @@ func (ioctx *IOContext) GetPoolName() (name string, err error) {
         return name, nil
     }
 }
+
+// ObjectListFunc is the type of the function called for each object visited
+// by ListObjects.
+type ObjectListFunc func(oid string)
+
+// ListObjects lists all of the objects in the pool associated with the I/O
+// context, and called the provided listFn function for each object, passing
+// to the function the name of the object.
+func (ioctx *IOContext) ListObjects(listFn ObjectListFunc) error {
+    var ctx C.rados_list_ctx_t
+    ret := C.rados_nobjects_list_open(ioctx.ioctx, &ctx)
+    if ret < 0 {
+        return RadosError(ret)
+    }
+    defer func() { C.rados_nobjects_list_close(ctx) }()
+
+    for {
+        var c_entry *C.char
+        ret := C.rados_nobjects_list_next(ctx, &c_entry, nil, nil)
+        if ret == -2 { // FIXME
+            return nil
+        } else if ret < 0 {
+            return RadosError(ret)
+        }
+        listFn(C.GoString(c_entry))
+    }
+
+    panic("invalid state")
+}

rados_test.go

@@ -11,6 +11,7 @@ import "io/ioutil"
 import "time"
 import "net"
 import "fmt"
+import "sort"
 
 func GetUUID() string {
     out, _ := exec.Command("uuidgen").Output()
@@ -373,3 +374,44 @@ func TestGetPoolName(t *testing.T) {
     ioctx.Destroy()
     conn.Shutdown()
 }
+
+func TestObjectIterator(t *testing.T) {
+    conn, _ := rados.NewConn()
+    conn.ReadDefaultConfigFile()
+    conn.Connect()
+
+    poolname := GetUUID()
+    err := conn.MakePool(poolname)
+    assert.NoError(t, err)
+
+    ioctx, err := conn.OpenIOContext(poolname)
+    assert.NoError(t, err)
+
+    objectList := []string{}
+    err = ioctx.ListObjects(func(oid string) {
+        objectList = append(objectList, oid)
+    })
+    assert.NoError(t, err)
+    assert.True(t, len(objectList) == 0)
+
+    createdList := []string{}
+    for i := 0; i < 200; i++ {
+        oid := GetUUID()
+        bytes_in := []byte("input data")
+        err = ioctx.Write(oid, bytes_in, 0)
+        assert.NoError(t, err)
+        createdList = append(createdList, oid)
+    }
+    assert.True(t, len(createdList) == 200)
+
+    err = ioctx.ListObjects(func(oid string) {
+        objectList = append(objectList, oid)
+    })
+    assert.NoError(t, err)
+    assert.Equal(t, len(objectList), len(createdList))
+
+    sort.Strings(objectList)
+    sort.Strings(createdList)
+
+    assert.Equal(t, objectList, createdList)
+}