add cbt interfaces

Signed-off-by: Lyndon-Li <lyonghui@vmware.com>

Author: Lyndon-Li

changelogs/unreleased/9716-Lyndon-Li

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+Fix issue #9709, add interfaces for CBT service and CBT bitmap

pkg/cbtservice/service.go

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+/*
+Copyright The Velero Contributors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package cbtservice
+
+import "context"
+
+// Range defines the range of a change
+type Range struct {
+	Offset int64
+	Length int64
+}
+
+// ChangeID uniquely identifies what the current allocated/changed blocks are queried for
+// could be a VolumeSnapshot name or any other values defined by customized services
+type ChangeID string
+
+// Service defines the methods for CBT service which could be implemented by Kubernetes SnapshotMetadataService or other customized services
+type Service interface {
+	// GetAllocatedBlocks enumerates the allocated blocks and call the record callback
+	GetAllocatedBlocks(ctx context.Context, changeID ChangeID, record func([]Range) error) error
+
+	// GetChangedBlocks enumerates the changed blocks between base and target and call the record callback
+	GetChangedBlocks(ctx context.Context, base ChangeID, target ChangeID, record func([]Range) error) error
+}

pkg/uploader/cbt/bitmap.go

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+/*
+Copyright The Velero Contributors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package cbt
+
+import "github.com/vmware-tanzu/velero/pkg/cbtservice"
+
+// Bitmap defines the methods to store and iterate the CBT bitmap
+type Bitmap interface {
+	// Set sets bits within the provided range
+	Set(cbtservice.Range)
+
+	// Iterator returns the iterator for the CBT Bitmap
+	Iterator() Iterator
+}
+
+// Iterator defines the methods to iterate the CBT bitmap and query the associated information
+type Iterator interface {
+	// BaseID returns the base changeID
+	BaseID() cbtservice.ChangeID
+
+	// ChangeID returns the current changeID
+	ChangeID() cbtservice.ChangeID
+
+	// BlockSize returns the granularity of the bitmap
+	BlockSize() int
+
+	// Count returns the toal number of count in the bitmap
+	Count() uint64
+
+	// Next returns the offset of the next set block and whether it comes to the end of the iteration
+	Next() (int64, bool)
+}