Initial QSfera import

Server/vendor/github.com/ceph/go-ceph/internal/cutil/iovec.go

@@ -0,0 +1,60 @@
+package cutil
+
+/*
+#include <stdlib.h>
+#include <sys/uio.h>
+*/
+import "C"
+import (
+	"unsafe"
+)
+
+// Iovec is a slice of iovec structs. Might have allocated C memory, so it must
+// be freed with the Free() method.
+type Iovec struct {
+	iovec []C.struct_iovec
+	sbs   []*SyncBuffer
+}
+
+const iovecSize = C.sizeof_struct_iovec
+
+// ByteSlicesToIovec creates an Iovec and links it to Go buffers in data.
+func ByteSlicesToIovec(data [][]byte) (v Iovec) {
+	n := len(data)
+	iovecMem := C.malloc(iovecSize * C.size_t(n))
+	v.iovec = (*[MaxIdx]C.struct_iovec)(iovecMem)[:n:n]
+	for i, b := range data {
+		sb := NewSyncBuffer(CPtr(&v.iovec[i].iov_base), b)
+		v.sbs = append(v.sbs, sb)
+		v.iovec[i].iov_len = C.size_t(len(b))
+	}
+	return
+}
+
+// Sync makes sure the slices contain the same as the C buffers
+func (v *Iovec) Sync() {
+	for _, sb := range v.sbs {
+		sb.Sync()
+	}
+}
+
+// Pointer returns a pointer to the iovec
+func (v *Iovec) Pointer() unsafe.Pointer {
+	return unsafe.Pointer(&v.iovec[0])
+}
+
+// Len returns a pointer to the iovec
+func (v *Iovec) Len() int {
+	return len(v.iovec)
+}
+
+// Free the C memory in the Iovec.
+func (v *Iovec) Free() {
+	for _, sb := range v.sbs {
+		sb.Release()
+	}
+	if len(v.iovec) != 0 {
+		C.free(unsafe.Pointer(&v.iovec[0]))
+	}
+	v.iovec = nil
+}