gristlabs_grist-core/app/common/ActionBundle.ts

/**
 * Basic definitions of types needed for ActionBundles.
 * See also EncActionBundle for how these are packaged for encryption.
 */

import {DocAction, UserAction} from 'app/common/DocActions';

// Metadata about the action.
export interface ActionInfo {
  time: number;       // Milliseconds since epoch.
  user: string;
  inst: string;
  desc?: string;
  otherId: number;
  linkId: number;
}

// Envelope contains information about recipients. In EncActionBundle, it's augmented with
// information about the symmetric key that encrypts this envelope's contents.
export interface Envelope {
  recipients: string[];       // sorted array of recipient instanceIds
}

// EnvContent packages arbitrary content with the index of the envelope to which it belongs.
export type EnvContent<Content> = [number, Content];

// ActionBundle contains actions arranged into envelopes, i.e. split up by sets of recipients.
// Note that different Envelopes contain different sets of recipients (which may overlap however).
// ActionBundle is what gets encrypted/decrypted and then sent between hub and instance.
export interface ActionBundle {
  actionNum: number;
  actionHash: string|null;        // a checksum of bundle, (not including actionHash and other parts).
  parentActionHash: string|null;  // a checksum of the parent action bundle, if there is one.
  envelopes: Envelope[];
  info: EnvContent<ActionInfo>;           // Should be in the envelope addressed to all peers.
  stored: Array<EnvContent<DocAction>>;
  calc: Array<EnvContent<DocAction>>;
}

export function getEnvContent<Content>(items: Array<EnvContent<Content>>): Content[] {
  return items.map((item) => item[1]);
}

// ======================================================================
// Types for ActionBundles used locally inside an instance.

// Local action received from the browser, that is not yet applied. It is usually one UserAction,
// but when multiple actions are sent by the browser in one call, they will form one bundle.
export interface UserActionBundle {
  info: ActionInfo;
  userActions: UserAction[];
}

// ActionBundle as received from the sandbox. It does not have some action metadata, but does have
// undo information and a retValue for each input UserAction. Note that it is satisfied by the
// ActionBundle structure defined in sandbox/grist/action_obj.py.
export interface SandboxActionBundle {
  envelopes: Envelope[];
  stored: Array<EnvContent<DocAction>>;
  direct: Array<EnvContent<boolean>>;
  calc: Array<EnvContent<DocAction>>;
  undo: Array<EnvContent<DocAction>>;   // Inverse actions for all 'stored' actions.
  retValues: any[];                     // Contains retValue for each of userActions.
}

// Local action that's been applied. It now has an actionNum, and includes doc actions packaged
// into envelopes, as well as undo, and userActions, which allow rebasing.
export interface LocalActionBundle extends ActionBundle {
  userActions: UserAction[];

  // Inverse actions for all 'stored' actions. These aren't shared and not split by envelope.
  // Applying 'undo' is governed by EDIT rather than READ permissions, so we always apply all undo
  // actions. (It is the result of applying 'undo' that may be addressed to different recipients).
  undo: DocAction[];
}