ddl

type BaseCallback struct {
}

type Callback interface {
	// OnChanged is called after schema is changed.
	OnChanged(err error) error
	// OnJobRunBefore is called before running job.
	OnJobRunBefore(job *model.Job)
	// OnJobUpdated is called after the running job is updated.
	OnJobUpdated(job *model.Job)
	// OnWatched is called after watching owner is completed.
	OnWatched(ctx goctx.Context)
}

type DDL interface {
	CreateSchema(ctx context.Context, name model.CIStr, charsetInfo *ast.CharsetOpt) error
	DropSchema(ctx context.Context, schema model.CIStr) error
	CreateTable(ctx context.Context, ident ast.Ident, cols []*ast.ColumnDef,
		constrs []*ast.Constraint, options []*ast.TableOption) error
	CreateTableWithLike(ctx context.Context, ident, referIdent ast.Ident) error
	DropTable(ctx context.Context, tableIdent ast.Ident) (err error)
	CreateIndex(ctx context.Context, tableIdent ast.Ident, unique bool, indexName model.CIStr,
		columnNames []*ast.IndexColName, indexOption *ast.IndexOption) error
	DropIndex(ctx context.Context, tableIdent ast.Ident, indexName model.CIStr) error
	GetInformationSchema() infoschema.InfoSchema
	AlterTable(ctx context.Context, tableIdent ast.Ident, spec []*ast.AlterTableSpec) error
	TruncateTable(ctx context.Context, tableIdent ast.Ident) error
	RenameTable(ctx context.Context, oldTableIdent, newTableIdent ast.Ident) error
	// SetLease will reset the lease time for online DDL change,
	// it's a very dangerous function and you must guarantee that all servers have the same lease time.
	SetLease(ctx goctx.Context, lease time.Duration)
	// GetLease returns current schema lease time.
	GetLease() time.Duration
	// Stats returns the DDL statistics.
	Stats(vars *variable.SessionVars) (map[string]interface{}, error)
	// GetScope gets the status variables scope.
	GetScope(status string) variable.ScopeFlag
	// Stop stops DDL worker.
	Stop() error
	// RegisterEventCh registers event channel for ddl.
	RegisterEventCh(chan<- *Event)
	// SchemaSyncer gets the schema syncer.
	SchemaSyncer() SchemaSyncer
	// OwnerManager gets the owner manager, and it's used for testing.
	OwnerManager() owner.Manager
	// WorkerVars gets the session variables for DDL worker.
	WorkerVars() *variable.SessionVars
	// SetHook sets the hook. It's exported for testing.
	SetHook(h Callback)
	// GetHook gets the hook. It's exported for testing.
	GetHook() Callback
}

type Event struct {
	Tp         model.ActionType
	TableInfo  *model.TableInfo
	ColumnInfo *model.ColumnInfo
	IndexInfo  *model.IndexInfo
}

type SchemaSyncer interface {
	// Init sets the global schema version path to etcd if it isn't exist,
	// then watch this path, and initializes the self schema version to etcd.
	Init(ctx goctx.Context) error
	// UpdateSelfVersion updates the current version to the self path on etcd.
	UpdateSelfVersion(ctx goctx.Context, version int64) error
	// RemoveSelfVersionPath remove the self path from etcd.
	RemoveSelfVersionPath() error
	// OwnerUpdateGlobalVersion updates the latest version to the global path on etcd until updating is successful or the ctx is done.
	OwnerUpdateGlobalVersion(ctx goctx.Context, version int64) error
	// GlobalVersionCh gets the chan for watching global version.
	GlobalVersionCh() clientv3.WatchChan
	// MustGetGlobalVersion gets the global version. The only reason it fails is that ctx is done.
	MustGetGlobalVersion(ctx goctx.Context) (int64, error)
	// Done() returns a channel that closes when the syncer is no longer being refreshed.
	Done() <-chan struct{}
	// Restart restarts the syncer when it's on longer being refreshed.
	Restart(ctx goctx.Context) error
	// OwnerCheckAllVersions checks whether all followers' schema version are equal to
	// the latest schema version. If the result is false, wait for a while and check again util the processing time reach 2 * lease.
	// It returns until all servers' versions are equal to the latest version or the ctx is done.
	OwnerCheckAllVersions(ctx goctx.Context, latestVer int64) error
}