lnd.xprv/channeldb/kvdb/interface.go
Olaoluwa Osuntokun fc808ac538
channeldb/kvdb: create new package for an abstract kv store
In this commit, we create a new package `kvdb`, which is meant to serve
as the basis for any future database abstractions within `lnd`. Rather
than directly use the `walletdb` package (which we base off of), we
instead use a series of type-aliases to re-type the fundamental
types/interfaces of the `walletdb` package. This lets us type
`kvdb.RwTx` instead of `walletdb.ReadWriteTransaction` everywhere.
Additionally, our usage of type-aliases is also intended to create an
easy pathway in the future wherein we can gradually re-defined or
re-implement these types to wean off of the `walletdb` package.
2020-03-18 19:34:45 -07:00

91 lines
3.6 KiB
Go

package kvdb
import (
"github.com/btcsuite/btcwallet/walletdb"
_ "github.com/btcsuite/btcwallet/walletdb/bdb" // Import to register backend.
)
// Update opens a database read/write transaction and executes the function f
// with the transaction passed as a parameter. After f exits, if f did not
// error, the transaction is committed. Otherwise, if f did error, the
// transaction is rolled back. If the rollback fails, the original error
// returned by f is still returned. If the commit fails, the commit error is
// returned.
var Update = walletdb.Update
// View opens a database read transaction and executes the function f with the
// transaction passed as a parameter. After f exits, the transaction is rolled
// back. If f errors, its error is returned, not a rollback error (if any
// occur).
var View = walletdb.View
// Batch is identical to the Update call, but it attempts to combine several
// individual Update transactions into a single write database transaction on
// an optimistic basis. This only has benefits if multiple goroutines call
// Batch.
var Batch = walletdb.Batch
// Create initializes and opens a database for the specified type. The
// arguments are specific to the database type driver. See the documentation
// for the database driver for further details.
//
// ErrDbUnknownType will be returned if the database type is not registered.
var Create = walletdb.Create
// Backend represents an ACID database. All database access is performed
// through read or read+write transactions.
type Backend = walletdb.DB
// Open opens an existing database for the specified type. The arguments are
// specific to the database type driver. See the documentation for the database
// driver for further details.
//
// ErrDbUnknownType will be returned if the database type is not registered.
var Open = walletdb.Open
// Driver defines a structure for backend drivers to use when they registered
// themselves as a backend which implements the Backend interface.
type Driver = walletdb.Driver
// ReadBucket represents a bucket (a hierarchical structure within the
// database) that is only allowed to perform read operations.
type ReadBucket = walletdb.ReadBucket
// ReadCursor represents a bucket cursor that can be positioned at the start or
// end of the bucket's key/value pairs and iterate over pairs in the bucket.
// This type is only allowed to perform database read operations.
type ReadCursor = walletdb.ReadCursor
// ReadTx represents a database transaction that can only be used for reads. If
// a database update must occur, use a RwTx.
type ReadTx = walletdb.ReadTx
// RwBucket represents a bucket (a hierarchical structure within the database)
// that is allowed to perform both read and write operations.
type RwBucket = walletdb.ReadWriteBucket
// RwCursor represents a bucket cursor that can be positioned at the start or
// end of the bucket's key/value pairs and iterate over pairs in the bucket.
// This abstraction is allowed to perform both database read and write
// operations.
type RwCursor = walletdb.ReadWriteCursor
// ReadWriteTx represents a database transaction that can be used for both
// reads and writes. When only reads are necessary, consider using a ReadTx
// instead.
type RwTx = walletdb.ReadWriteTx
var (
// ErrBucketNotFound is returned when trying to access a bucket that
// has not been created yet.
ErrBucketNotFound = walletdb.ErrBucketNotFound
// ErrBucketExists is returned when creating a bucket that already
// exists.
ErrBucketExists = walletdb.ErrBucketExists
// ErrDatabaseNotOpen is returned when a database instance is accessed
// before it is opened or after it is closed.
ErrDatabaseNotOpen = walletdb.ErrDbNotOpen
)