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