120 lines
4.5 KiB
Go
120 lines
4.5 KiB
Go
// Copyright 2015 The etcd Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package mvcc
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import (
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"github.com/coreos/etcd/lease"
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"github.com/coreos/etcd/mvcc/backend"
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"github.com/coreos/etcd/mvcc/mvccpb"
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)
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type RangeOptions struct {
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Limit int64
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Rev int64
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Count bool
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}
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type RangeResult struct {
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KVs []mvccpb.KeyValue
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Rev int64
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Count int
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}
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type KV interface {
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// Rev returns the current revision of the KV.
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Rev() int64
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// FirstRev returns the first revision of the KV.
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// After a compaction, the first revision increases to the compaction
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// revision.
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FirstRev() int64
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// Range gets the keys in the range at rangeRev.
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// The returned rev is the current revision of the KV when the operation is executed.
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// If rangeRev <=0, range gets the keys at currentRev.
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// If `end` is nil, the request returns the key.
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// If `end` is not nil and not empty, it gets the keys in range [key, range_end).
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// If `end` is not nil and empty, it gets the keys greater than or equal to key.
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// Limit limits the number of keys returned.
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// If the required rev is compacted, ErrCompacted will be returned.
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Range(key, end []byte, ro RangeOptions) (r *RangeResult, err error)
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// Put puts the given key, value into the store. Put also takes additional argument lease to
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// attach a lease to a key-value pair as meta-data. KV implementation does not validate the lease
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// id.
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// A put also increases the rev of the store, and generates one event in the event history.
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// The returned rev is the current revision of the KV when the operation is executed.
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Put(key, value []byte, lease lease.LeaseID) (rev int64)
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// DeleteRange deletes the given range from the store.
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// A deleteRange increases the rev of the store if any key in the range exists.
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// The number of key deleted will be returned.
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// The returned rev is the current revision of the KV when the operation is executed.
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// It also generates one event for each key delete in the event history.
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// if the `end` is nil, deleteRange deletes the key.
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// if the `end` is not nil, deleteRange deletes the keys in range [key, range_end).
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DeleteRange(key, end []byte) (n, rev int64)
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// TxnBegin begins a txn. Only Txn prefixed operation can be executed, others will be blocked
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// until txn ends. Only one on-going txn is allowed.
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// TxnBegin returns an int64 txn ID.
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// All txn prefixed operations with same txn ID will be done with the same rev.
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TxnBegin() int64
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// TxnEnd ends the on-going txn with txn ID. If the on-going txn ID is not matched, error is returned.
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TxnEnd(txnID int64) error
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// TxnRange returns the current revision of the KV when the operation is executed.
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TxnRange(txnID int64, key, end []byte, ro RangeOptions) (r *RangeResult, err error)
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TxnPut(txnID int64, key, value []byte, lease lease.LeaseID) (rev int64, err error)
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TxnDeleteRange(txnID int64, key, end []byte) (n, rev int64, err error)
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// Compact frees all superseded keys with revisions less than rev.
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Compact(rev int64) (<-chan struct{}, error)
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// Hash retrieves the hash of KV state and revision.
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// This method is designed for consistency checking purpose.
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Hash() (hash uint32, revision int64, err error)
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// Commit commits txns into the underlying backend.
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Commit()
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// Restore restores the KV store from a backend.
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Restore(b backend.Backend) error
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Close() error
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}
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// WatchableKV is a KV that can be watched.
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type WatchableKV interface {
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KV
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Watchable
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}
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// Watchable is the interface that wraps the NewWatchStream function.
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type Watchable interface {
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// NewWatchStream returns a WatchStream that can be used to
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// watch events happened or happening on the KV.
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NewWatchStream() WatchStream
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}
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// ConsistentWatchableKV is a WatchableKV that understands the consistency
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// algorithm and consistent index.
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// If the consistent index of executing entry is not larger than the
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// consistent index of ConsistentWatchableKV, all operations in
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// this entry are skipped and return empty response.
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type ConsistentWatchableKV interface {
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WatchableKV
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// ConsistentIndex returns the current consistent index of the KV.
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ConsistentIndex() uint64
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}
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