go-ceph/rados/read_op.go

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package rados
// #cgo LDFLAGS: -lrados
// #include <errno.h>
// #include <stdlib.h>
// #include <rados/librados.h>
//
import "C"
import (
"unsafe"
)
// ReadOp manages a set of discrete object read actions that will be performed
// together atomically.
type ReadOp struct {
operation
op C.rados_read_op_t
}
// CreateReadOp returns a newly constructed read operation.
func CreateReadOp() *ReadOp {
return &ReadOp{
op: C.rados_create_read_op(),
}
}
// Release the resources associated with this read operation.
func (r *ReadOp) Release() {
C.rados_release_read_op(r.op)
r.op = nil
r.free()
}
// Operate will perform the operation(s).
func (r *ReadOp) Operate(ioctx *IOContext, oid string, flags OperationFlags) error {
if err := ioctx.validate(); err != nil {
return err
}
cOid := C.CString(oid)
defer C.free(unsafe.Pointer(cOid))
ret := C.rados_read_op_operate(r.op, ioctx.ioctx, cOid, C.int(flags))
return r.update(readOp, ret)
}
func (r *ReadOp) operateCompat(ioctx *IOContext, oid string) error {
switch err := r.Operate(ioctx, oid, OperationNoFlag).(type) {
case nil:
return nil
case OperationError:
return err.OpError
default:
return err
}
}
// AssertExists assures the object targeted by the read op exists.
//
// Implements:
// void rados_read_op_assert_exists(rados_read_op_t read_op);
func (r *ReadOp) AssertExists() {
C.rados_read_op_assert_exists(r.op)
}
// GetOmapValues is used to iterate over a set, or sub-set, of omap keys
// as part of a read operation. An GetOmapStep is returned from this
// function. The GetOmapStep may be used to iterate over the key-value
// pairs after the Operate call has been performed.
func (r *ReadOp) GetOmapValues(startAfter, filterPrefix string, maxReturn uint64) *GetOmapStep {
gos := newGetOmapStep()
r.steps = append(r.steps, gos)
cStartAfter := C.CString(startAfter)
cFilterPrefix := C.CString(filterPrefix)
defer C.free(unsafe.Pointer(cStartAfter))
defer C.free(unsafe.Pointer(cFilterPrefix))
C.rados_read_op_omap_get_vals2(
r.op,
cStartAfter,
cFilterPrefix,
C.uint64_t(maxReturn),
&gos.iter,
gos.more,
gos.rval,
)
return gos
}