Config: Refactor version packages (#1887)

* Config: Move config versions to separate pacakges

* Config: Move version tests to blackbox texts

* Config: Protect registerVersion from overflow

* Config: Protect against version already registered

config/versions/v5/v5.go

@@ -0,0 +1,54 @@
+package v5
+
+import (
+	"context"
+	"errors"
+	"strconv"
+
+	"github.com/buger/jsonparser"
+)
+
+// Version implements ConfigVersion
+type Version struct{}
+
+// UpgradeConfig handles upgrading config for OrderManager:
+// * Sets OrderManager config to defaults if it doesn't exist or enabled is null
+// * Sets respectOrderHistoryLimits to true if it doesn't exist or is null
+// * Sets futuresTrackingSeekDuration to positive if it's negative
+func (*Version) UpgradeConfig(_ context.Context, e []byte) ([]byte, error) {
+	_, valueType, _, err := jsonparser.Get(e, "orderManager", "enabled")
+	switch {
+	case errors.Is(err, jsonparser.KeyPathNotFoundError), valueType == jsonparser.Null:
+		return jsonparser.Set(e, DefaultOrderbookConfig, "orderManager")
+	case err != nil:
+		return e, err
+	}
+
+	_, valueType, _, err = jsonparser.Get(e, "orderManager", "respectOrderHistoryLimits")
+	if errors.Is(err, jsonparser.KeyPathNotFoundError) || valueType == jsonparser.Null {
+		if e, err = jsonparser.Set(e, []byte(`true`), "orderManager", "respectOrderHistoryLimits"); err != nil {
+			return e, err
+		}
+	}
+
+	if i, err := jsonparser.GetInt(e, "orderManager", "futuresTrackingSeekDuration"); err != nil {
+		if e, err = jsonparser.Set(e, []byte(DefaultFuturesTrackingSeekDuration), "orderManager", "futuresTrackingSeekDuration"); err != nil {
+			return e, err
+		}
+	} else if i < 0 {
+		if e, err = jsonparser.Set(e, []byte(strconv.FormatInt(-i, 10)), "orderManager", "futuresTrackingSeekDuration"); err != nil {
+			return e, err
+		}
+	}
+	return e, nil
+}
+
+// DowngradeConfig just reverses the futuresTrackingSeekDuration to negative, and leaves everything else alone
+func (*Version) DowngradeConfig(_ context.Context, e []byte) ([]byte, error) {
+	if i, err := jsonparser.GetInt(e, "orderManager", "futuresTrackingSeekDuration"); err == nil && i > 0 {
+		if e, err = jsonparser.Set(e, []byte(strconv.FormatInt(-i, 10)), "orderManager", "futuresTrackingSeekDuration"); err != nil {
+			return e, err
+		}
+	}
+	return e, nil
+}