silverbullet/common/syscalls/sync.ts

import { SysCallMapping, System } from "../../plugos/system.ts";
import type { SyncEndpoint } from "../../plug-api/silverbullet-syscall/sync.ts";
import { SpaceSync, SyncStatusItem } from "../spaces/sync.ts";
import { HttpSpacePrimitives } from "../spaces/http_space_primitives.ts";
import { SpacePrimitives } from "../spaces/space_primitives.ts";
import { race, timeout } from "../async_util.ts";

export function syncSyscalls(
  localSpace: SpacePrimitives,
  system: System<any>,
): SysCallMapping {
  return {
    "sync.syncAll": async (
      _ctx,
      endpoint: SyncEndpoint,
      snapshot: Record<string, SyncStatusItem>,
    ): Promise<
      {
        snapshot: Record<string, SyncStatusItem>;
        operations: number;
        // The reason to not just throw an Error is so that the partially updated snapshot can still be saved
        error?: string;
      }
    > => {
      const { spaceSync } = setupSync(endpoint, snapshot);

      try {
        const operations = await spaceSync.syncFiles(
          SpaceSync.primaryConflictResolver,
        );
        return {
          // And convert back to JSON
          snapshot: Object.fromEntries(spaceSync.snapshot),
          operations,
        };
      } catch (e: any) {
        return {
          snapshot: Object.fromEntries(spaceSync.snapshot),
          operations: -1,
          error: e.message,
        };
      }
    },
    "sync.syncFile": async (
      _ctx,
      endpoint: SyncEndpoint,
      snapshot: Record<string, SyncStatusItem>,
      name: string,
    ): Promise<
      {
        snapshot: Record<string, SyncStatusItem>;
        operations: number;
        // The reason to not just throw an Error is so that the partially updated snapshot can still be saved
        error?: string;
      }
    > => {
      const { spaceSync, remoteSpace } = setupSync(endpoint, snapshot);
      try {
        const localHash = (await localSpace.getFileMeta(name)).lastModified;
        let remoteHash: number | undefined = undefined;
        try {
          remoteHash =
            (await race([remoteSpace.getFileMeta(name), timeout(1000)]))
              .lastModified;
        } catch (e: any) {
          if (e.message.includes("File not found")) {
            // File doesn't exist remotely, that's ok
          } else {
            throw e;
          }
        }

        const operations = await spaceSync.syncFile(
          name,
          localHash,
          remoteHash,
          SpaceSync.primaryConflictResolver,
        );
        return {
          // And convert back to JSON
          snapshot: Object.fromEntries(spaceSync.snapshot),
          operations,
        };
      } catch (e: any) {
        return {
          snapshot: Object.fromEntries(spaceSync.snapshot),
          operations: -1,
          error: e.message,
        };
      }
    },
    "sync.check": async (_ctx, endpoint: SyncEndpoint): Promise<void> => {
      const syncSpace = new HttpSpacePrimitives(
        endpoint.url,
        endpoint.user,
        endpoint.password,
      );
      // Let's just fetch metadata for the SETTINGS.md file (which should always exist)
      try {
        await race([
          syncSpace.getFileMeta("SETTINGS.md"),
          timeout(2000),
        ]);
      } catch (e: any) {
        console.error("Sync check failure", e.message);
        throw e;
      }
    },
  };

  function setupSync(
    endpoint: SyncEndpoint,
    snapshot: Record<string, SyncStatusItem>,
  ) {
    const remoteSpace = new HttpSpacePrimitives(
      endpoint.url,
      endpoint.user,
      endpoint.password,
      // Base64 PUTs to support mobile
      true,
    );
    // Convert from JSON to a Map
    const syncStatusMap = new Map<string, SyncStatusItem>(
      Object.entries(snapshot),
    );
    const spaceSync = new SpaceSync(
      localSpace,
      remoteSpace,
      syncStatusMap,
      // Log to the "sync" plug sandbox
      system.loadedPlugs.get("sync")!.sandbox!,
    );
    return { spaceSync, remoteSpace };
  }
}