rados: add RmOmapKeys WriteOp function

Reimplement RmOmapKeys in term of a new RmOmapKeys function on the
WriteOp.

Signed-off-by: John Mulligan <jmulligan@redhat.com>

rados/omap.go

@@ -183,6 +183,42 @@ func (gos *GetOmapStep) More() bool {
 	return gos.more != 0
 }
 
+// removeOmapKeysStep is a write operation step used to track state, especially
+// C memory, across the setup and use of a WriteOp.
+type removeOmapKeysStep struct {
+	withRefs
+	withoutUpdate
+
+	// arguments:
+	cKeys **C.char
+	cNum  C.size_t
+}
+
+func newRemoveOmapKeysStep(keys []string) *removeOmapKeysStep {
+	cKeys := C.malloc(C.size_t(len(keys)) * ptrSize)
+	roks := &removeOmapKeysStep{
+		cKeys: (**C.char)(cKeys),
+		cNum:  C.size_t(len(keys)),
+	}
+	roks.add(cKeys)
+
+	i := 0
+	for _, key := range keys {
+		ckp := (**C.char)(unsafe.Pointer(uintptr(cKeys) + uintptr(i)*ptrSize))
+		*ckp = C.CString(key)
+		roks.add(unsafe.Pointer(*ckp))
+		i++
+	}
+
+	runtime.SetFinalizer(roks, opStepFinalizer)
+	return roks
+}
+
+func (roks *removeOmapKeysStep) free() {
+	roks.cKeys = nil
+	roks.withRefs.free()
+}
+
 // SetOmap appends the map `pairs` to the omap `oid`
 func (ioctx *IOContext) SetOmap(oid string, pairs map[string][]byte) error {
 	op := CreateWriteOp()
@@ -276,33 +312,10 @@ func (ioctx *IOContext) GetAllOmapValues(oid string, startAfter string, filterPr
 
 // RmOmapKeys removes the specified `keys` from the omap `oid`
 func (ioctx *IOContext) RmOmapKeys(oid string, keys []string) error {
-	c_oid := C.CString(oid)
-	defer C.free(unsafe.Pointer(c_oid))
-
-	var c *C.char
-	ptrSize := unsafe.Sizeof(c)
-
-	c_keys := C.malloc(C.size_t(len(keys)) * C.size_t(ptrSize))
-	defer C.free(unsafe.Pointer(c_keys))
-
-	i := 0
-	for _, key := range keys {
-		c_key_ptr := (**C.char)(unsafe.Pointer(uintptr(c_keys) + uintptr(i)*ptrSize))
-		*c_key_ptr = C.CString(key)
-		defer C.free(unsafe.Pointer(*c_key_ptr))
-		i++
-	}
-
-	op := C.rados_create_write_op()
-	C.rados_write_op_omap_rm_keys(
-		op,
-		(**C.char)(c_keys),
-		C.size_t(len(keys)))
-
-	ret := C.rados_write_op_operate(op, ioctx.ioctx, c_oid, nil, 0)
-	C.rados_release_write_op(op)
-
-	return getError(ret)
+	op := CreateWriteOp()
+	defer op.Release()
+	op.RmOmapKeys(keys)
+	return op.operateCompat(ioctx, oid)
 }
 
 // CleanOmap clears the omap `oid`

rados/write_op.go

@@ -101,3 +101,13 @@ func (w *WriteOp) SetOmap(pairs map[string][]byte) {
 		sos.cLengths,
 		sos.cNum)
 }
+
+// RmOmapKeys removes the specified `keys` from the omap `oid`.
+func (w *WriteOp) RmOmapKeys(keys []string) {
+	roks := newRemoveOmapKeysStep(keys)
+	w.steps = append(w.steps, roks)
+	C.rados_write_op_omap_rm_keys(
+		w.op,
+		roks.cKeys,
+		roks.cNum)
+}