hexmap/server/action/syncable.go

package action

import (
	"errors"
	"git.reya.zone/reya/hexmap/server/state"
	"go.uber.org/zap/zapcore"
)

var (
	// ErrNoOp is returned when an action has no effect.
	ErrNoOp = errors.New("action's effects were already applied, or it's an empty action")
	// ErrNoTransparentColors is returned when a user tries to set their active color or a cell color to transparent.
	// Transparent here is defined as having an alpha component of less than 15 (0xF).
	ErrNoTransparentColors = errors.New("transparent colors not allowed")
)

type SyncableType string

// Syncable is the interface for actions that can be shared between clients.
type Syncable interface {
	zapcore.ObjectMarshaler
	// Type gives the Javascript type that is sent over the wire.
	Type() SyncableType
	// Apply causes the action's effects to be applied to s, mutating it in place.
	// All syncable.Actions must conform to the standard that if an action can't be correctly applied, or if it would
	// have no effect, it returns an error without changing s.
	// If an action can be correctly applied but would have no effect, it should return ErrNoOp.
	// If an action is correctly applied and has an effect, it should return nil.
	Apply(s *state.Synced) error
}

type SyncableSlice []Syncable

func (s SyncableSlice) MarshalLogArray(encoder zapcore.ArrayEncoder) error {
	var finalErr error = nil
	for _, a := range s {
		err := encoder.AppendObject(a)
		if err != nil && finalErr == nil {
			finalErr = err
		}
	}
	return finalErr
}