94 lines
2.6 KiB
Go
94 lines
2.6 KiB
Go
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package etcd
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import (
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"github.com/btcsuite/btcwallet/walletdb"
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)
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// readWriteTx holds a reference to the STM transaction.
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type readWriteTx struct {
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// stm is the reference to the parent STM.
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stm STM
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// active is true if the transaction hasn't been
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// committed yet.
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active bool
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}
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// newReadWriteTx creates an rw transaction with the passed STM.
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func newReadWriteTx(stm STM) *readWriteTx {
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return &readWriteTx{
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stm: stm,
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active: true,
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}
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}
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// rooBucket is a helper function to return the always present
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// root bucket.
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func rootBucket(tx *readWriteTx) *readWriteBucket {
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return newReadWriteBucket(tx, rootBucketID())
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}
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// ReadBucket opens the root bucket for read only access. If the bucket
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// described by the key does not exist, nil is returned.
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func (tx *readWriteTx) ReadBucket(key []byte) walletdb.ReadBucket {
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return rootBucket(tx).NestedReadWriteBucket(key)
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}
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// Rollback closes the transaction, discarding changes (if any) if the
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// database was modified by a write transaction.
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func (tx *readWriteTx) Rollback() error {
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// If the transaction has been closed roolback will fail.
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if !tx.active {
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return walletdb.ErrTxClosed
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}
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// Rollback the STM and set the tx to inactive.
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tx.stm.Rollback()
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tx.active = false
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return nil
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}
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// ReadWriteBucket opens the root bucket for read/write access. If the
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// bucket described by the key does not exist, nil is returned.
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func (tx *readWriteTx) ReadWriteBucket(key []byte) walletdb.ReadWriteBucket {
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return rootBucket(tx).NestedReadWriteBucket(key)
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}
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// CreateTopLevelBucket creates the top level bucket for a key if it
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// does not exist. The newly-created bucket it returned.
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func (tx *readWriteTx) CreateTopLevelBucket(key []byte) (walletdb.ReadWriteBucket, error) {
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return rootBucket(tx).CreateBucketIfNotExists(key)
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}
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// DeleteTopLevelBucket deletes the top level bucket for a key. This
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// errors if the bucket can not be found or the key keys a single value
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// instead of a bucket.
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func (tx *readWriteTx) DeleteTopLevelBucket(key []byte) error {
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return rootBucket(tx).DeleteNestedBucket(key)
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}
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// Commit commits the transaction if not already committed. Will return
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// error if the underlying STM fails.
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func (tx *readWriteTx) Commit() error {
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// Commit will fail if the transaction is already committed.
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if !tx.active {
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return walletdb.ErrTxClosed
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}
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// Try committing the transaction.
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if err := tx.stm.Commit(); err != nil {
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return err
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}
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// Mark the transaction as not active after commit.
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tx.active = false
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return nil
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}
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// OnCommit sets the commit callback (overriding if already set).
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func (tx *readWriteTx) OnCommit(cb func()) {
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tx.stm.OnCommit(cb)
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}
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