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/*
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 *  This file is part of CoCalc: Copyright © 2020 Sagemath, Inc.
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 *  License: MS-RSL – see LICENSE.md for details
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 */
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/*
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Make a SyncTable which does not use a changefeed at all.
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It does the initial database read as usual, and also
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writes changes as usual, but does not use a changefeed
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at all.   Instead changes are injected by calling
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a function.
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This is used, e.g., by a backend project for implementing a version
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of SyncTable, where the project itself handles all changes,
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not the database or hubs.   However, data is still persisted
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to the central database.
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Returned object is not cached in any way.
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*/
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import { EventEmitter } from "events";
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import { SyncTable, Client } from "./synctable";
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import { bind_methods } from "@cocalc/util/misc";
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export function synctable_no_changefeed(
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  query,
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  options,
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  client: Client,
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  throttle_changes?: undefined | number,
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): SyncTable {
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  if (options == null) {
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    options = [];
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  }
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  const client2 = new ClientNoChangefeed(client);
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  return new SyncTable(query, options, client2, throttle_changes, true, false);
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}
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class ClientNoChangefeed extends EventEmitter {
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  private client: Client;
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  constructor(client) {
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    super();
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    bind_methods(this, [
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      "query",
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      "dbg",
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      "query_cancel",
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      "emit_connected",
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      "emit_signed_in",
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    ]);
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    this.client = client;
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    // These MUST be after the binds above, obviously.
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    client.on("connected", this.emit_connected);
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    client.on("signed_in", this.emit_signed_in);
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  }
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  private emit_connected(): void {
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    this.emit("connected");
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  }
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  private emit_signed_in(): void {
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    this.emit("signed_in");
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  }
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  public is_project(): boolean {
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    return this.client.is_project();
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  }
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  public is_browser(): boolean {
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    return this.client.is_browser();
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  }
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  public is_compute_server(): boolean {
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    return this.client.is_compute_server();
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  }
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  public async touch_project(
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    project_id: string,
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    compute_server_id?: number,
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  ): Promise<void> {
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    await this.client.touch_project(project_id, compute_server_id);
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  }
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  public is_connected(): boolean {
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    return this.client.is_connected();
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  }
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  public is_signed_in(): boolean {
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    return this.client.is_signed_in();
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  }
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  public server_time(): Date {
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    return this.client.server_time();
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  }
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  public dbg(s: string): Function {
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    return this.client.dbg(s);
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  }
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  public query(opts): void {
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    if (opts.changes) {
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      this.changefeed_query(opts);
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    } else {
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      this.client.query(opts);
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    }
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  }
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  private changefeed_query(opts): void {
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    opts.changes = false;
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    this.client.query(opts);
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  }
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  public query_cancel(_): void {
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    // no op since no changefeed.
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    this.client.removeListener("connected", this.emit_connected);
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    this.client.removeListener("signed_in", this.emit_signed_in);
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  }
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  public alert_message(opts): void {
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    if (this.client.alert_message != null) {
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      this.client.alert_message(opts);
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    }
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  }
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  is_deleted = (_path: string, _project_id: string) => {
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    // not implemented yet in general
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    return undefined;
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  };
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}
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