VersionedHashDBM class

A VersionedDBM implementation that wraps HashDBM with delta overlay transactions and version history.

Implemented types

• VersionedDBM

Constructors

VersionedHashDBM(RandomAccessFile file, {int buckets = 10007, bool flush = true, bool crc = false, bool readonly = false})

Open a versioned database. The file should be opened with the same mode semantics as HashDBM. Optional parameters match HashDBM.

Properties

current → int

Current (latest) version number.

no setter, override

hashCode → int

The hash code for this object.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

versions → List<int>

List of available versions (base..current).

no setter, override

Methods

apply(Map<BytesKey, Uint8List?> pending) → void

Apply a set of pending changes as a new delta version.

at(int version) → DBM

Read-only view at a specific version.

override

begin() → Transaction

Start a new transaction.

override

clear() → void

Erases all data and resets the internal structure, but does not reclaim storage.

override

close() → void

flush() and close the underlying file.

override

compact() → int

Truncate trailing free blocks at end-of-file and return bytes reclaimed.

override

count() → int

Get the number of records stored in the database as a Uint64

override

entries() → Iterator<MapEntry<Uint8List, Uint8List>>

Iterate over all keys and values in the database

override

entriesAt(int version) → Iterator<MapEntry<Uint8List, Uint8List>>

Iterate entries at a specific version, merging base + deltas.

flatten() → void

Merge all deltas into the base table and convert to plain format. After flattening, the file can be reopened with plain HashDBM.

override

flush() → void

Flush all data to external storage.

override

get(Uint8List key) → Uint8List?

Get a value from the database using key, or else return null

override

merge({int? through}) → void

Merge deltas through the given version into the base table. If through is null, merges all deltas through current.

override

modified() → DateTime

Get the last time the database was opened or modified.

override

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

put(Uint8List key, Uint8List value) → Uint8List?

Add a key, value pair to the underlying store, overwriting any existing values. Returns the old value if one existed, otherwise returns the new value.

override

putIfAbsent(Uint8List key, Uint8List value) → Uint8List

Add a key, value pair to the underlying store if not key is in the underlying store. Returns the old value if key existed, otherwise value is returned.

override

remove(Uint8List key) → Uint8List?

Remove a value from the database using key. If the key had an associated value, return the value or else return null

override

resolve(Uint8List key, int version) → Uint8List?

Resolve a key at a specific version by scanning deltas then base.

size() → int

Get the size, in bytes, of data stored. This is intended to track approximate data size and will differ from the size of the file itself.

override

toString() → String

A string representation of this object.

inherited

version() → int

Get the version of the underlying implementation as a 32bit integer.

override

Operators

operator ==(Object other) → bool

The equality operator.

inherited