rados: use rados_write_op_omap_set2()

WriteOp.SetOmap now uses rados_write_op_omap_set2().

The entirety of setOmapStep struct was removed as it's not necessary for it to
own the various C-allocated values passed to rados_write_op_omap_set2()
as arguments. rados_write_op_omap_set2() makes copies of all the string-based
args [1], so it's sufficient for them to be short lived.

[1] 2bd3dd512a/src/librados/librados_c.cc (L3852-L3871)

rados/omap.go

@@ -10,69 +10,8 @@ import "C"
 import (
 	"runtime"
 	"unsafe"
-
-	"github.com/ceph/go-ceph/internal/cutil"
 )
 
-// setOmapStep is a write op step. It holds C memory used in the operation.
-type setOmapStep struct {
-	withRefs
-	withoutUpdate
-
-	// C arguments
-	cKeys    cutil.CPtrCSlice
-	cValues  cutil.CPtrCSlice
-	cLengths cutil.SizeTCSlice
-	cNum     C.size_t
-}
-
-func newSetOmapStep(pairs map[string][]byte) *setOmapStep {
-
-	maplen := len(pairs)
-	cKeys := cutil.NewCPtrCSlice(maplen)
-	cValues := cutil.NewCPtrCSlice(maplen)
-	cLengths := cutil.NewSizeTCSlice(maplen)
-
-	sos := &setOmapStep{
-		cKeys:    cKeys,
-		cValues:  cValues,
-		cLengths: cLengths,
-		cNum:     C.size_t(maplen),
-	}
-
-	var i uintptr
-	for key, value := range pairs {
-		// key
-		ck := C.CString(key)
-		sos.add(unsafe.Pointer(ck))
-		cKeys[i] = cutil.CPtr(ck)
-
-		// value and its length
-		vlen := cutil.SizeT(len(value))
-		if vlen > 0 {
-			cv := C.CBytes(value)
-			sos.add(cv)
-			cValues[i] = cutil.CPtr(cv)
-		} else {
-			cValues[i] = nil
-		}
-
-		cLengths[i] = vlen
-
-		i++
-	}
-
-	runtime.SetFinalizer(sos, opStepFinalizer)
-	return sos
-}
-
-func (sos *setOmapStep) free() {
-	sos.cKeys.Free()
-	sos.cValues.Free()
-	sos.cLengths.Free()
-	sos.withRefs.free()
-}
-
 // OmapKeyValue items are returned by the GetOmapStep's Next call.
 type OmapKeyValue struct {
 	Key   string

rados/write_op.go

@@ -10,6 +10,7 @@ import "C"
 import (
 	"unsafe"
 
+	"github.com/ceph/go-ceph/internal/cutil"
 	ts "github.com/ceph/go-ceph/internal/timespec"
 )
 
@@ -92,14 +93,27 @@ func (w *WriteOp) Create(exclusive CreateOption) {
 
 // SetOmap appends the map `pairs` to the omap `oid`.
 func (w *WriteOp) SetOmap(pairs map[string][]byte) {
-	sos := newSetOmapStep(pairs)
-	w.steps = append(w.steps, sos)
-	C.rados_write_op_omap_set(
+	keys := make([]string, len(pairs))
+	values := make([][]byte, len(pairs))
+	idx := 0
+	for k, v := range pairs {
+		keys[idx] = k
+		values[idx] = v
+		idx++
+	}
+
+	cKeys := cutil.NewBufferGroupStrings(keys)
+	cValues := cutil.NewBufferGroupBytes(values)
+	defer cKeys.Free()
+	defer cValues.Free()
+
+	C.rados_write_op_omap_set2(
 		w.op,
-		(**C.char)(sos.cKeys.Ptr()),
-		(**C.char)(sos.cValues.Ptr()),
-		(*C.size_t)(sos.cLengths.Ptr()),
-		sos.cNum)
+		(**C.char)(cKeys.BuffersPtr()),
+		(**C.char)(cValues.BuffersPtr()),
+		(*C.size_t)(cKeys.LengthsPtr()),
+		(*C.size_t)(cValues.LengthsPtr()),
+		(C.size_t)(len(pairs)))
 }
 
 // RmOmapKeys removes the specified `keys` from the omap `oid`.