90 lines
3.0 KiB
Go
90 lines
3.0 KiB
Go
// Copyright (c) 2015-2016 The btcsuite developers
|
|
// Use of this source code is governed by an ISC
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package database
|
|
|
|
import (
|
|
"fmt"
|
|
|
|
"github.com/btcsuite/btclog"
|
|
)
|
|
|
|
// Driver defines a structure for backend drivers to use when they registered
|
|
// themselves as a backend which implements the DB interface.
|
|
type Driver struct {
|
|
// DbType is the identifier used to uniquely identify a specific
|
|
// database driver. There can be only one driver with the same name.
|
|
DbType string
|
|
|
|
// Create is the function that will be invoked with all user-specified
|
|
// arguments to create the database. This function must return
|
|
// ErrDbExists if the database already exists.
|
|
Create func(args ...interface{}) (DB, error)
|
|
|
|
// Open is the function that will be invoked with all user-specified
|
|
// arguments to open the database. This function must return
|
|
// ErrDbDoesNotExist if the database has not already been created.
|
|
Open func(args ...interface{}) (DB, error)
|
|
|
|
// UseLogger uses a specified Logger to output package logging info.
|
|
UseLogger func(logger btclog.Logger)
|
|
}
|
|
|
|
// driverList holds all of the registered database backends.
|
|
var drivers = make(map[string]*Driver)
|
|
|
|
// RegisterDriver adds a backend database driver to available interfaces.
|
|
// ErrDbTypeRegistered will be returned if the database type for the driver has
|
|
// already been registered.
|
|
func RegisterDriver(driver Driver) error {
|
|
if _, exists := drivers[driver.DbType]; exists {
|
|
str := fmt.Sprintf("driver %q is already registered",
|
|
driver.DbType)
|
|
return makeError(ErrDbTypeRegistered, str, nil)
|
|
}
|
|
|
|
drivers[driver.DbType] = &driver
|
|
return nil
|
|
}
|
|
|
|
// SupportedDrivers returns a slice of strings that represent the database
|
|
// drivers that have been registered and are therefore supported.
|
|
func SupportedDrivers() []string {
|
|
supportedDBs := make([]string, 0, len(drivers))
|
|
for _, drv := range drivers {
|
|
supportedDBs = append(supportedDBs, drv.DbType)
|
|
}
|
|
return supportedDBs
|
|
}
|
|
|
|
// 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 the database type is not registered.
|
|
func Create(dbType string, args ...interface{}) (DB, error) {
|
|
drv, exists := drivers[dbType]
|
|
if !exists {
|
|
str := fmt.Sprintf("driver %q is not registered", dbType)
|
|
return nil, makeError(ErrDbUnknownType, str, nil)
|
|
}
|
|
|
|
return drv.Create(args...)
|
|
}
|
|
|
|
// 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 the database type is not registered.
|
|
func Open(dbType string, args ...interface{}) (DB, error) {
|
|
drv, exists := drivers[dbType]
|
|
if !exists {
|
|
str := fmt.Sprintf("driver %q is not registered", dbType)
|
|
return nil, makeError(ErrDbUnknownType, str, nil)
|
|
}
|
|
|
|
return drv.Open(args...)
|
|
}
|