mirror of
https://github.com/ceph/go-ceph
synced 2024-12-19 21:02:12 +00:00
9841283344
The DiffIterate call accepts a data structure argument containing the parameters of the image to "diff" and a callback function. This callback is called in the C code, making use of the recently added callbacks helper. The callback itself is called with the offset and length of the differing area in the image as well as a data parameter so that a common function can distinguish or update different data for different calls if needed (compare to a void* in C). Signed-off-by: John Mulligan <jmulligan@redhat.com>
137 lines
4.2 KiB
Go
137 lines
4.2 KiB
Go
package rbd
|
|
|
|
/*
|
|
#cgo LDFLAGS: -lrbd
|
|
#undef _GNU_SOURCE
|
|
#include <errno.h>
|
|
#include <stdlib.h>
|
|
#include <rbd/librbd.h>
|
|
|
|
extern int callDiffIterateCallback(uint64_t ofs, size_t len, int exists, int index);
|
|
|
|
// cgo is having trouble converting the callback from the librbd header
|
|
// to a unsafe.Pointer. This shim exists solely to help it along.
|
|
static inline int wrap_rbd_diff_iterate2(
|
|
rbd_image_t image,
|
|
const char *fromsnapname,
|
|
uint64_t ofs, uint64_t len,
|
|
uint8_t include_parent, uint8_t whole_object,
|
|
void *cb,
|
|
void *arg) {
|
|
return rbd_diff_iterate2(image, fromsnapname, ofs, len, include_parent, whole_object, cb, arg);
|
|
}
|
|
*/
|
|
import "C"
|
|
|
|
import (
|
|
"unsafe"
|
|
|
|
"github.com/ceph/go-ceph/internal/callbacks"
|
|
)
|
|
|
|
var diffIterateCallbacks = callbacks.New()
|
|
|
|
// DiffIncludeParent values control if the difference should include the parent
|
|
// image.
|
|
type DiffIncludeParent uint8
|
|
|
|
// DiffWholeObject values control if the diff extents should cover the whole
|
|
// object.
|
|
type DiffWholeObject uint8
|
|
|
|
// DiffIterateCallback defines the function signature needed for the
|
|
// DiffIterate callback.
|
|
//
|
|
// The function will be called with the arguments: offset, length, exists, and
|
|
// data. The offset and length correspond to the changed region of the image.
|
|
// The exists value is set to zero if the region is known to be zeros,
|
|
// otherwise it is set to 1. The data value is the extra data parameter that
|
|
// was set on the DiffIterateConfig and is meant to be used for passing
|
|
// arbitrary user-defined items to the callback function.
|
|
//
|
|
// The callback can trigger the iteration to terminate early by returning
|
|
// a non-zero error code.
|
|
type DiffIterateCallback func(uint64, uint64, int, interface{}) int
|
|
|
|
// DiffIterateConfig is used to define the parameters of a DiffIterate call.
|
|
// Callback, Offset, and Length should always be specified when passed to
|
|
// DiffIterate. The other values are optional.
|
|
type DiffIterateConfig struct {
|
|
SnapName string
|
|
Offset uint64
|
|
Length uint64
|
|
IncludeParent DiffIncludeParent
|
|
WholeObject DiffWholeObject
|
|
Callback DiffIterateCallback
|
|
Data interface{}
|
|
}
|
|
|
|
const (
|
|
// ExcludeParent will exclude the parent from the diff.
|
|
ExcludeParent = DiffIncludeParent(0)
|
|
// IncludeParent will include the parent in the diff.
|
|
IncludeParent = DiffIncludeParent(1)
|
|
|
|
// DisableWholeObject will not use the whole object in the diff.
|
|
DisableWholeObject = DiffWholeObject(0)
|
|
// EnableWholeObject will use the whole object in the diff.
|
|
EnableWholeObject = DiffWholeObject(1)
|
|
)
|
|
|
|
// DiffIterate calls a callback on changed extents of an image.
|
|
//
|
|
// Calling DiffIterate will cause the callback specified in the
|
|
// DiffIterateConfig to be called as many times as there are changed
|
|
// regions in the image (controlled by the parameters as passed to librbd).
|
|
//
|
|
// See the documentation of DiffIterateCallback for a description of the
|
|
// arguments to the callback and the return behavior.
|
|
//
|
|
// Implements:
|
|
// int rbd_diff_iterate2(rbd_image_t image,
|
|
// const char *fromsnapname,
|
|
// uint64_t ofs, uint64_t len,
|
|
// uint8_t include_parent, uint8_t whole_object,
|
|
// int (*cb)(uint64_t, size_t, int, void *),
|
|
// void *arg);
|
|
func (image *Image) DiffIterate(config DiffIterateConfig) error {
|
|
|
|
if err := image.validate(imageIsOpen); err != nil {
|
|
return err
|
|
}
|
|
if config.Callback == nil {
|
|
return RBDError(C.EINVAL)
|
|
}
|
|
|
|
var cSnapName *C.char
|
|
if config.SnapName != NoSnapshot {
|
|
cSnapName = C.CString(config.SnapName)
|
|
defer C.free(unsafe.Pointer(cSnapName))
|
|
}
|
|
|
|
cbIndex := diffIterateCallbacks.Add(config)
|
|
defer diffIterateCallbacks.Remove(cbIndex)
|
|
|
|
ret := C.wrap_rbd_diff_iterate2(
|
|
image.image,
|
|
cSnapName,
|
|
C.uint64_t(config.Offset),
|
|
C.uint64_t(config.Length),
|
|
C.uint8_t(config.IncludeParent),
|
|
C.uint8_t(config.WholeObject),
|
|
C.callDiffIterateCallback,
|
|
unsafe.Pointer(uintptr(cbIndex)))
|
|
|
|
return getError(ret)
|
|
}
|
|
|
|
//export diffIterateCallback
|
|
func diffIterateCallback(
|
|
offset C.uint64_t, length C.size_t, exists, index C.int) C.int {
|
|
|
|
v := diffIterateCallbacks.Lookup(int(index))
|
|
config := v.(DiffIterateConfig)
|
|
return C.int(config.Callback(
|
|
uint64(offset), uint64(length), int(exists), config.Data))
|
|
}
|