(core) move home server into core

Summary: This moves enough server material into core to run a home server.  The data engine is not yet incorporated (though in manual testing it works when ported).

Test Plan: existing tests pass

Reviewers: dsagal

Reviewed By: dsagal

Differential Revision: https://phab.getgrist.com/D2552

app/common/ActionBundle.ts

@@ -0,0 +1,74 @@
+/**
+ * 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>>;
+  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[];
+}