new sync algo, squashed commit of the following:

commit 692bb794aea5609b9e9abf5228620f4479e50983 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Sun Feb 27 17:52:43 2022 +0800 bump to 0.3.0 commit 77335412ad2da2b5bd1ed5075061a5af006e3c36 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Sun Feb 27 17:50:57 2022 +0800 change titles for minimal intrusive design commit 2812adebb84344d384749a62acb63fd0c6fd509d Author: fyears <1142836+fyears@users.noreply.github.com> Date: Sun Feb 27 17:30:53 2022 +0800 remove syncv1 commit 22fc24a76c9851740bbc7c0177d1cb2526e15d8b Author: fyears <1142836+fyears@users.noreply.github.com> Date: Sun Feb 27 17:30:27 2022 +0800 full notice to any one commit d56ea24a78f6dc1fbea2740011ee1cea9c403d4c Author: fyears <1142836+fyears@users.noreply.github.com> Date: Sat Feb 26 23:11:14 2022 +0800 fix test commit 759f82593bbfb9b49079cfd80dbadbbafc0287e5 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Sat Feb 26 21:59:25 2022 +0800 obfuscate metadata on remote commit 9b6bf05288af0e52d0f02468e5ac8757f4f896df Author: fyears <1142836+fyears@users.noreply.github.com> Date: Sat Feb 26 21:33:52 2022 +0800 avoid re-uploading if meta not changed commit 03be1453764e48e99207f44467ee4d5801072ed8 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Sat Feb 26 00:35:52 2022 +0800 add password condition commit 7f899f7c2572df3e2a35e16cbdaab94db113f366 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Sat Feb 26 00:22:58 2022 +0800 add decision branch for easier debugging commit cf4071bf3156356ae6ec3a9cb187c2cb541d1b17 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Fri Feb 25 23:40:52 2022 +0800 change folder error commit 964493dd998699a1d53018a201637bda192c4baa Author: fyears <1142836+fyears@users.noreply.github.com> Date: Fri Feb 25 23:09:44 2022 +0800 finnaly remote remove should be working commit 2888e65452f9c0e1dde6005f012c3ee0a6313c3f Author: fyears <1142836+fyears@users.noreply.github.com> Date: Fri Feb 25 01:18:15 2022 +0800 optimize comparation commit 024936951d6180b1296c2a5d56c5bf5d468e9ae7 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Fri Feb 25 01:14:44 2022 +0800 allow uploading extra meta commit 007006701d536da2b4b46389941980579bbc4e67 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Thu Feb 24 01:08:58 2022 +0800 add logic to fetch extra meta commit c9d3a05ca1bf45c06f22233124670e5e45b5f5f1 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Thu Feb 24 00:29:16 2022 +0800 another way to deal with trash commit 82d455f8bf60f7bac8eb4e299a2ca44c331a6d7f Author: fyears <1142836+fyears@users.noreply.github.com> Date: Thu Feb 24 00:28:51 2022 +0800 add return buffer for downloading commit b8e6b79bc078def2854bc73578b7f520cc39ab34 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Wed Feb 23 00:16:06 2022 +0800 half way to actual sync commit 90cceb1411b46af9741f2caa3ab8beafaf69c1b2 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Tue Feb 22 23:36:09 2022 +0800 cleaner way to remember the folder being kept commit c1afb763cc4e0f7905c83e0a8eb20f8ed969a279 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Tue Feb 22 00:03:21 2022 +0800 simplified way to get plans for sync algo v2 commit 5c5ecce39eb3854900f1f5b79c7beb189e78a6a7 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Mon Feb 21 23:13:58 2022 +0800 archive the old sync algo v1 doc commit 75cdfa1ee9834600f83ded6672b102de2c5f9616 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Mon Feb 21 23:13:14 2022 +0800 simplify sync algo v2 commit dc9275835d961de07efcbaa81657e4745242e72a Author: fyears <1142836+fyears@users.noreply.github.com> Date: Mon Feb 21 22:58:57 2022 +0800 add way to skip recording removing commit f9712ef96021dfed4ae33e6c649f78e940b7e530 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Mon Feb 21 09:38:09 2022 +0800 fix sync commit 9007dcf22ef317dde36ac4f1dd589d05cc8d5cf6 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Mon Feb 21 00:54:21 2022 +0800 fix assignment commit 77abee6ad443b62353ed3913e0945ea7d1314f87 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Mon Feb 21 00:28:43 2022 +0800 draft of sync v2 commit a0c26238bf60692e095cfd8527abf937255b56d4 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Mon Feb 21 00:23:19 2022 +0800 how to deal with folders commit c10f92a7e8d3c4a4f4c585e39e0abad1a5376c02 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Sun Feb 20 23:39:16 2022 +0800 helper func to get parents commit f903c98b3b7b9d1e785d04b9fc0cfcafdc6e5661 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Sun Feb 20 23:31:21 2022 +0800 add optional ending slash to getFolderLevels commit 2d67c9b2b941e676588fa43ab289fab79f567e5e Author: fyears <1142836+fyears@users.noreply.github.com> Date: Sun Feb 20 14:44:44 2022 +0800 update sync algo v2 commit 491ed1bb85759df2411706fd02d740acb5598ce6 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Sun Feb 20 14:34:51 2022 +0800 dry run mode commit dfd588dcef512ba7dfe760008bcf97138b97e339 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Sat Feb 19 23:14:32 2022 +0800 prettier commit eae580f882a045ae9df799b816e68c3500704131 Author: fyears <1142836+fyears@users.noreply.github.com> Date: Sat Feb 19 23:12:29 2022 +0800 draft design for sync algo v2
2022-02-27 17:54:31 +08:00
parent 6045155fbb
commit df2d98272c
20 changed files with 1281 additions and 467 deletions
@@ -80,3 +80,35 @@ export interface UriParams {

 // 80 days
 export const OAUTH2_FORCE_EXPIRE_MILLISECONDS = 1000 * 60 * 60 * 24 * 80;
+
+type DecisionTypeForFile =
+  | "skipUploading" // special, mtimeLocal === mtimeRemote
+  | "uploadLocalDelHistToRemote" // "delLocalIfExists && delRemoteIfExists && cleanLocalDelHist && uploadLocalDelHistToRemote"
+  | "keepRemoteDelHist" // "delLocalIfExists && delRemoteIfExists && cleanLocalDelHist && keepRemoteDelHist"
+  | "uploadLocalToRemote" // "skipLocal && uploadLocalToRemote && cleanLocalDelHist && cleanRemoteDelHist"
+  | "downloadRemoteToLocal"; // "downloadRemoteToLocal && skipRemote && cleanLocalDelHist && cleanRemoteDelHist"
+
+type DecisionTypeForFolder =
+  | "createFolder"
+  | "uploadLocalDelHistToRemoteFolder"
+  | "keepRemoteDelHistFolder"
+  | "skipFolder";
+
+export type DecisionType = DecisionTypeForFile | DecisionTypeForFolder;
+
+export interface FileOrFolderMixedState {
+  key: string;
+  existLocal?: boolean;
+  existRemote?: boolean;
+  mtimeLocal?: number;
+  mtimeRemote?: number;
+  deltimeLocal?: number;
+  deltimeRemote?: number;
+  sizeLocal?: number;
+  sizeRemote?: number;
+  changeMtimeUsingMapping?: boolean;
+  decision?: DecisionType;
+  decisionBranch?: number;
+  syncDone?: "done";
+  remoteEncryptedKey?: string;
+}
@@ -34,11 +34,13 @@ import {
 import { DEFAULT_S3_CONFIG } from "./remoteForS3";
 import { DEFAULT_WEBDAV_CONFIG } from "./remoteForWebdav";
 import { RemotelySaveSettingTab } from "./settings";
-import type { SyncStatusType } from "./sync";
+import { fetchMetadataFile, parseRemoteItems, SyncStatusType } from "./sync";
 import { doActualSync, getSyncPlan, isPasswordOk } from "./sync";
 import { messyConfigToNormal, normalConfigToMessy } from "./configPersist";

 import * as origLog from "loglevel";
+import { DeletionOnRemote, MetadataOnRemote } from "./metadataOnRemote";
+import { SyncAlgoV2Modal } from "./syncAlgoV2Notice";
 const log = origLog.getLogger("rs-default");

 const DEFAULT_SETTINGS: RemotelySavePluginSettings = {
@@ -51,6 +53,7 @@ const DEFAULT_SETTINGS: RemotelySavePluginSettings = {
  currLogLevel: "info",
  vaultRandomID: "",
  autoRunEveryMilliseconds: -1,
+  agreeToUploadExtraMetadata: false,
 };

 interface OAuth2Info {
@@ -61,7 +64,7 @@ interface OAuth2Info {
  revokeAuthSetting?: Setting;
 }

-type SyncTriggerSourceType = "manual" | "auto";
+type SyncTriggerSourceType = "manual" | "auto" | "dry";

 const iconNameSyncWait = `remotely-save-sync-wait`;
 const iconNameSyncRunning = `remotely-save-sync-running`;
@@ -89,7 +92,7 @@ export default class RemotelySavePlugin extends Plugin {
    const getNotice = (x: string) => {
      // only show notices in manual mode
      // no notice in auto mode
-      if (triggerSource === "manual") {
+      if (triggerSource === "manual" || triggerSource === "dry") {
        new Notice(x);
      }
    };
@@ -122,14 +125,22 @@ export default class RemotelySavePlugin extends Plugin {
        );
      }

+      const MAX_STEPS = 8;
+
+      if (triggerSource === "dry") {
+        getNotice(
+          `0/${MAX_STEPS} Remotely Save running in dry mode, not actual file changes would happen.`
+        );
+      }
+
      //log.info(`huh ${this.settings.password}`)
      getNotice(
-        `1/7 Remotely Save Sync Preparing (${this.settings.serviceType})`
+        `1/${MAX_STEPS} Remotely Save Sync Preparing (${this.settings.serviceType})`
      );
      this.syncStatus = "preparing";

-      getNotice("2/7 Starting to fetch remote meta data.");
-      this.syncStatus = "getting_remote_meta";
+      getNotice(`2/${MAX_STEPS} Starting to fetch remote meta data.`);
+      this.syncStatus = "getting_remote_files_list";
      const self = this;
      const client = new RemoteClient(
        this.settings.serviceType,
@@ -143,17 +154,7 @@ export default class RemotelySavePlugin extends Plugin {
      const remoteRsp = await client.listFromRemote();
      log.info(remoteRsp);

-      getNotice("3/7 Starting to fetch local meta data.");
-      this.syncStatus = "getting_local_meta";
-      const local = this.app.vault.getAllLoadedFiles();
-      const localHistory = await loadDeleteRenameHistoryTableByVault(
-        this.db,
-        this.settings.vaultRandomID
-      );
-      // log.info(local);
-      // log.info(localHistory);
-
-      getNotice("4/7 Checking password correct or not.");
+      getNotice(`3/${MAX_STEPS} Checking password correct or not.`);
      this.syncStatus = "checking_password";
      const passwordCheckResult = await isPasswordOk(
        remoteRsp.Contents,
@@ -164,43 +165,81 @@ export default class RemotelySavePlugin extends Plugin {
        throw Error(passwordCheckResult.reason);
      }

-      getNotice("5/7 Starting to generate sync plan.");
-      this.syncStatus = "generating_plan";
-      const syncPlan = await getSyncPlan(
+      getNotice(`4/${MAX_STEPS} Trying to fetch extra meta data from remote.`);
+      this.syncStatus = "getting_remote_extra_meta";
+      const { remoteStates, metadataFile } = await parseRemoteItems(
        remoteRsp.Contents,
-        local,
-        localHistory,
        this.db,
        this.settings.vaultRandomID,
        client.serviceType,
        this.settings.password
      );
-      log.info(syncPlan.mixedStates); // for debugging
-      await insertSyncPlanRecordByVault(
+      const origMetadataOnRemote = await fetchMetadataFile(
+        metadataFile,
+        client,
+        this.app.vault,
+        this.settings.password
+      );
+
+      getNotice(`5/${MAX_STEPS} Starting to fetch local meta data.`);
+      this.syncStatus = "getting_local_meta";
+      const local = this.app.vault.getAllLoadedFiles();
+      const localHistory = await loadDeleteRenameHistoryTableByVault(
        this.db,
-        syncPlan,
        this.settings.vaultRandomID
      );
+      // log.info(local);
+      // log.info(localHistory);

-      // The operations above are read only and kind of safe.
+      getNotice(`6/${MAX_STEPS} Starting to generate sync plan.`);
+      this.syncStatus = "generating_plan";
+      const { plan, sortedKeys, deletions } = await getSyncPlan(
+        remoteStates,
+        local,
+        origMetadataOnRemote.deletions,
+        localHistory,
+        client.serviceType,
+        this.settings.password
+      );
+      log.info(plan.mixedStates); // for debugging
+      if (triggerSource !== "dry") {
+        await insertSyncPlanRecordByVault(
+          this.db,
+          plan,
+          this.settings.vaultRandomID
+        );
+      }
+
+      // The operations above are almost read only and kind of safe.
      // The operations below begins to write or delete (!!!) something.

-      getNotice("6/7 Remotely Save Sync data exchanging!");
+      if (triggerSource !== "dry") {
+        getNotice(`7/${MAX_STEPS} Remotely Save Sync data exchanging!`);

-      this.syncStatus = "syncing";
-      await doActualSync(
-        client,
-        this.db,
-        this.settings.vaultRandomID,
-        this.app.vault,
-        syncPlan,
-        this.settings.password,
-        (i: number, totalCount: number, pathName: string, decision: string) =>
-          self.setCurrSyncMsg(i, totalCount, pathName, decision)
-      );
+        this.syncStatus = "syncing";
+        await doActualSync(
+          client,
+          this.db,
+          this.settings.vaultRandomID,
+          this.app.vault,
+          plan,
+          sortedKeys,
+          metadataFile,
+          origMetadataOnRemote,
+          deletions,
+          (key: string) => self.trash(key),
+          this.settings.password,
+          (i: number, totalCount: number, pathName: string, decision: string) =>
+            self.setCurrSyncMsg(i, totalCount, pathName, decision)
+        );
+      } else {
+        this.syncStatus = "syncing";
+        getNotice(
+          `7/${MAX_STEPS} Remotely Save real sync is skipped in dry run mode.`
+        );
+      }

-      getNotice("7/7 Remotely Save finish!");
-      this.currSyncMsg = "";
+      getNotice(`8/${MAX_STEPS} Remotely Save finish!`);
      this.syncStatus = "finish";
      this.syncStatus = "idle";

@@ -474,22 +513,24 @@ export default class RemotelySavePlugin extends Plugin {
      },
    });

+    this.addCommand({
+      id: "start-sync-dry-run",
+      name: "start sync (dry run only)",
+      icon: iconNameSyncWait,
+      callback: async () => {
+        this.syncRun("dry");
+      },
+    });
+
    this.addSettingTab(new RemotelySaveSettingTab(this.app, this));

    // this.registerDomEvent(document, "click", (evt: MouseEvent) => {
    //   log.info("click", evt);
    // });

-    if (
-      this.settings.autoRunEveryMilliseconds !== undefined &&
-      this.settings.autoRunEveryMilliseconds !== null &&
-      this.settings.autoRunEveryMilliseconds > 0
-    ) {
-      const intervalID = window.setInterval(() => {
-        this.syncRun("auto");
-      }, this.settings.autoRunEveryMilliseconds);
-      this.autoRunIntervalID = intervalID;
-      this.registerInterval(intervalID);
+    if (!this.settings.agreeToUploadExtraMetadata) {
+      const syncAlgoV2Modal = new SyncAlgoV2Modal(this.app, this);
+      syncAlgoV2Modal.open();
    }
  }

@@ -602,10 +643,35 @@ export default class RemotelySavePlugin extends Plugin {
    }
  }

+  async trash(x: string) {
+    if (!(await this.app.vault.adapter.trashSystem(x))) {
+      await this.app.vault.adapter.trashLocal(x);
+    }
+  }
+
  async prepareDB() {
    this.db = await prepareDBs(this.settings.vaultRandomID);
  }

+  enableAutoSyncIfSet() {
+    if (
+      this.settings.autoRunEveryMilliseconds !== undefined &&
+      this.settings.autoRunEveryMilliseconds !== null &&
+      this.settings.autoRunEveryMilliseconds > 0
+    ) {
+      const intervalID = window.setInterval(() => {
+        this.syncRun("auto");
+      }, this.settings.autoRunEveryMilliseconds);
+      this.autoRunIntervalID = intervalID;
+      this.registerInterval(intervalID);
+    }
+  }
+
+  async saveAgreeToUseNewSyncAlgorithm() {
+    this.settings.agreeToUploadExtraMetadata = true;
+    await this.saveSettings();
+  }
+
  destroyDBs() {
    /* destroyDBs(this.db); */
  }
@@ -0,0 +1,87 @@
+import isEqual from "lodash/isEqual";
+import { base64url } from "rfc4648";
+import { reverseString } from "./misc";
+
+const DEFAULT_README_FOR_METADATAONREMOTE =
+  "Do NOT edit or delete the file manually. This file is for the plugin remotely-save to store some necessary meta data on the remote services. Its content is slightly obfuscated.";
+
+const DEFAULT_VERSION_FOR_METADATAONREMOTE = "20220220";
+
+export const DEFAULT_FILE_NAME_FOR_METADATAONREMOTE =
+  "_remotely-save-metadata-on-remote.json";
+
+export const DEFAULT_FILE_NAME_FOR_METADATAONREMOTE2 =
+  "_remotely-save-metadata-on-remote.bin";
+
+export interface DeletionOnRemote {
+  key: string;
+  actionWhen: number;
+}
+
+export interface MetadataOnRemote {
+  version?: string;
+  generatedWhen?: number;
+  deletions?: DeletionOnRemote[];
+}
+
+export const isEqualMetadataOnRemote = (
+  a: MetadataOnRemote,
+  b: MetadataOnRemote
+) => {
+  const m1 = a === undefined ? { deletions: [] } : a;
+  const m2 = b === undefined ? { deletions: [] } : b;
+
+  // we only need to compare deletions
+  const d1 = m1.deletions === undefined ? [] : m1.deletions;
+  const d2 = m2.deletions === undefined ? [] : m2.deletions;
+  return isEqual(d1, d2);
+};
+
+export const serializeMetadataOnRemote = (x: MetadataOnRemote) => {
+  const y = x;
+
+  if (y["version"] === undefined) {
+    y["version"] === DEFAULT_VERSION_FOR_METADATAONREMOTE;
+  }
+  if (y["generatedWhen"] === undefined) {
+    y["generatedWhen"] = Date.now();
+  }
+  if (y["deletions"] === undefined) {
+    y["deletions"] = [];
+  }
+
+  const z = {
+    readme: DEFAULT_README_FOR_METADATAONREMOTE,
+    d: reverseString(
+      base64url.stringify(Buffer.from(JSON.stringify(x), "utf-8"), {
+        pad: false,
+      })
+    ),
+  };
+
+  return JSON.stringify(z, null, 2);
+};
+
+export const deserializeMetadataOnRemote = (x: string | ArrayBuffer) => {
+  let y1 = "";
+  if (typeof x === "string") {
+    y1 = x;
+  } else {
+    y1 = new TextDecoder().decode(x);
+  }
+  const y2: any = JSON.parse(y1);
+
+  if (!("readme" in y2 && "d" in y2)) {
+    throw Error("invalid remote meta data file!");
+  }
+
+  const y3 = JSON.parse(
+    (
+      base64url.parse(reverseString(y2["d"]), {
+        out: Buffer.allocUnsafe as any,
+        loose: true,
+      }) as Buffer
+    ).toString("utf-8")
+  ) as MetadataOnRemote;
+  return y3;
+};
@@ -38,7 +38,7 @@ export const isHiddenPath = (item: string, loose: boolean = true) => {
 * @param x string
 * @returns string[] might be empty
 */
-export const getFolderLevels = (x: string) => {
+export const getFolderLevels = (x: string, addEndingSlash: boolean = false) => {
  const res: string[] = [];

  if (x === "" || x === "/") {
@@ -48,10 +48,14 @@ export const getFolderLevels = (x: string) => {
  const y1 = x.split("/");
  let i = 0;
  for (let index = 0; index + 1 < y1.length; index++) {
-    const k = y1.slice(0, index + 1).join("/");
-    if (k !== "" && k !== "/") {
-      res.push(k);
+    let k = y1.slice(0, index + 1).join("/");
+    if (k === "" || k === "/") {
+      continue;
    }
+    if (addEndingSlash) {
+      k = `${k}/`;
+    }
+    res.push(k);
  }
  return res;
 };
@@ -157,6 +161,24 @@ export const getPathFolder = (a: string) => {
  return b.endsWith("/") ? b : `${b}/`;
 };

+/**
+ * If input is already a folder, returns its folder;
+ * And if input is a file, returns its direname.
+ * @param a
+ * @returns
+ */
+export const getParentFolder = (a: string) => {
+  const b = path.posix.dirname(a);
+  if (b === "." || b === "/") {
+    // the root
+    return "/";
+  }
+  if (b.endsWith("/")) {
+    return b;
+  }
+  return `${b}/`;
+};
+
 /**
 * https://stackoverflow.com/questions/54511144
 * @param a
@@ -102,7 +102,9 @@ export class RemoteClient {
    isRecursively: boolean = false,
    password: string = "",
    remoteEncryptedKey: string = "",
-    foldersCreatedBefore: Set<string> | undefined = undefined
+    foldersCreatedBefore: Set<string> | undefined = undefined,
+    uploadRaw: boolean = false,
+    rawContent: string | ArrayBuffer = ""
  ) => {
    if (this.serviceType === "s3") {
      return await s3.uploadToRemote(
@@ -112,7 +114,9 @@ export class RemoteClient {
        vault,
        isRecursively,
        password,
-        remoteEncryptedKey
+        remoteEncryptedKey,
+        uploadRaw,
+        rawContent
      );
    } else if (this.serviceType === "webdav") {
      return await webdav.uploadToRemote(
@@ -121,7 +125,9 @@ export class RemoteClient {
        vault,
        isRecursively,
        password,
-        remoteEncryptedKey
+        remoteEncryptedKey,
+        uploadRaw,
+        rawContent
      );
    } else if (this.serviceType === "dropbox") {
      return await dropbox.uploadToRemote(
@@ -131,7 +137,9 @@ export class RemoteClient {
        isRecursively,
        password,
        remoteEncryptedKey,
-        foldersCreatedBefore
+        foldersCreatedBefore,
+        uploadRaw,
+        rawContent
      );
    } else if (this.serviceType === "onedrive") {
      return await onedrive.uploadToRemote(
@@ -141,7 +149,9 @@ export class RemoteClient {
        isRecursively,
        password,
        remoteEncryptedKey,
-        foldersCreatedBefore
+        foldersCreatedBefore,
+        uploadRaw,
+        rawContent
      );
    } else {
      throw Error(`not supported service type ${this.serviceType}`);
@@ -167,7 +177,8 @@ export class RemoteClient {
    vault: Vault,
    mtime: number,
    password: string = "",
-    remoteEncryptedKey: string = ""
+    remoteEncryptedKey: string = "",
+    skipSaving: boolean = false
  ) => {
    if (this.serviceType === "s3") {
      return await s3.downloadFromRemote(
@@ -177,7 +188,8 @@ export class RemoteClient {
        vault,
        mtime,
        password,
-        remoteEncryptedKey
+        remoteEncryptedKey,
+        skipSaving
      );
    } else if (this.serviceType === "webdav") {
      return await webdav.downloadFromRemote(
@@ -186,7 +198,8 @@ export class RemoteClient {
        vault,
        mtime,
        password,
-        remoteEncryptedKey
+        remoteEncryptedKey,
+        skipSaving
      );
    } else if (this.serviceType === "dropbox") {
      return await dropbox.downloadFromRemote(
@@ -195,7 +208,8 @@ export class RemoteClient {
        vault,
        mtime,
        password,
-        remoteEncryptedKey
+        remoteEncryptedKey,
+        skipSaving
      );
    } else if (this.serviceType === "onedrive") {
      return await onedrive.downloadFromRemote(
@@ -204,7 +218,8 @@ export class RemoteClient {
        vault,
        mtime,
        password,
-        remoteEncryptedKey
+        remoteEncryptedKey,
+        skipSaving
      );
    } else {
      throw Error(`not supported service type ${this.serviceType}`);
@@ -400,7 +400,9 @@ export const uploadToRemote = async (
  isRecursively: boolean = false,
  password: string = "",
  remoteEncryptedKey: string = "",
-  foldersCreatedBefore: Set<string> | undefined = undefined
+  foldersCreatedBefore: Set<string> | undefined = undefined,
+  uploadRaw: boolean = false,
+  rawContent: string | ArrayBuffer = ""
 ) => {
  await client.init();

@@ -415,6 +417,9 @@ export const uploadToRemote = async (
  if (isFolder && isRecursively) {
    throw Error("upload function doesn't implement recursive function yet!");
  } else if (isFolder && !isRecursively) {
+    if (uploadRaw) {
+      throw Error(`you specify uploadRaw, but you also provide a folder key!`);
+    }
    // folder
    if (password === "") {
      // if not encrypted, mkdir a remote folder
@@ -448,7 +453,16 @@ export const uploadToRemote = async (
  } else {
    // file
    // we ignore isRecursively parameter here
-    const localContent = await vault.adapter.readBinary(fileOrFolderPath);
+    let localContent = undefined;
+    if (uploadRaw) {
+      if (typeof rawContent === "string") {
+        localContent = new TextEncoder().encode(rawContent);
+      } else {
+        localContent = rawContent;
+      }
+    } else {
+      localContent = await vault.adapter.readBinary(fileOrFolderPath);
+    }
    let remoteContent = localContent;
    if (password !== "") {
      remoteContent = await encryptArrayBuffer(localContent, password);
@@ -551,13 +565,16 @@ export const downloadFromRemote = async (
  vault: Vault,
  mtime: number,
  password: string = "",
-  remoteEncryptedKey: string = ""
+  remoteEncryptedKey: string = "",
+  skipSaving: boolean = false
 ) => {
  await client.init();

  const isFolder = fileOrFolderPath.endsWith("/");

-  await mkdirpInVault(fileOrFolderPath, vault);
+  if (!skipSaving) {
+    await mkdirpInVault(fileOrFolderPath, vault);
+  }

  // the file is always local file
  // we need to encrypt it
@@ -565,6 +582,7 @@ export const downloadFromRemote = async (
  if (isFolder) {
    // mkdirp locally is enough
    // do nothing here
+    return new ArrayBuffer(0);
  } else {
    let downloadFile = fileOrFolderPath;
    if (password !== "") {
@@ -576,9 +594,12 @@ export const downloadFromRemote = async (
    if (password !== "") {
      localContent = await decryptArrayBuffer(remoteContent, password);
    }
-    await vault.adapter.writeBinary(fileOrFolderPath, localContent, {
-      mtime: mtime,
-    });
+    if (!skipSaving) {
+      await vault.adapter.writeBinary(fileOrFolderPath, localContent, {
+        mtime: mtime,
+      });
+    }
+    return localContent;
  }
 };

@@ -624,7 +624,9 @@ export const uploadToRemote = async (
  isRecursively: boolean = false,
  password: string = "",
  remoteEncryptedKey: string = "",
-  foldersCreatedBefore: Set<string> | undefined = undefined
+  foldersCreatedBefore: Set<string> | undefined = undefined,
+  uploadRaw: boolean = false,
+  rawContent: string | ArrayBuffer = ""
 ) => {
  await client.init();

@@ -640,6 +642,9 @@ export const uploadToRemote = async (
  if (isFolder && isRecursively) {
    throw Error("upload function doesn't implement recursive function yet!");
  } else if (isFolder && !isRecursively) {
+    if (uploadRaw) {
+      throw Error(`you specify uploadRaw, but you also provide a folder key!`);
+    }
    // folder
    if (password === "") {
      // if not encrypted, mkdir a remote folder
@@ -682,7 +687,16 @@ export const uploadToRemote = async (
  } else {
    // file
    // we ignore isRecursively parameter here
-    const localContent = await vault.adapter.readBinary(fileOrFolderPath);
+    let localContent = undefined;
+    if (uploadRaw) {
+      if (typeof rawContent === "string") {
+        localContent = new TextEncoder().encode(rawContent);
+      } else {
+        localContent = rawContent;
+      }
+    } else {
+      localContent = await vault.adapter.readBinary(fileOrFolderPath);
+    }
    let remoteContent = localContent;
    if (password !== "") {
      remoteContent = await encryptArrayBuffer(localContent, password);
@@ -751,17 +765,21 @@ export const downloadFromRemote = async (
  vault: Vault,
  mtime: number,
  password: string = "",
-  remoteEncryptedKey: string = ""
+  remoteEncryptedKey: string = "",
+  skipSaving: boolean = false
 ) => {
  await client.init();

  const isFolder = fileOrFolderPath.endsWith("/");

-  await mkdirpInVault(fileOrFolderPath, vault);
+  if (!skipSaving) {
+    await mkdirpInVault(fileOrFolderPath, vault);
+  }

  if (isFolder) {
    // mkdirp locally is enough
    // do nothing here
+    return new ArrayBuffer(0);
  } else {
    let downloadFile = fileOrFolderPath;
    if (password !== "") {
@@ -773,9 +791,12 @@ export const downloadFromRemote = async (
    if (password !== "") {
      localContent = await decryptArrayBuffer(remoteContent, password);
    }
-    await vault.adapter.writeBinary(fileOrFolderPath, localContent, {
-      mtime: mtime,
-    });
+    if (!skipSaving) {
+      await vault.adapter.writeBinary(fileOrFolderPath, localContent, {
+        mtime: mtime,
+      });
+    }
+    return localContent;
  }
 };

@@ -99,7 +99,9 @@ export const uploadToRemote = async (
  vault: Vault,
  isRecursively: boolean = false,
  password: string = "",
-  remoteEncryptedKey: string = ""
+  remoteEncryptedKey: string = "",
+  uploadRaw: boolean = false,
+  rawContent: string | ArrayBuffer = ""
 ) => {
  let uploadFile = fileOrFolderPath;
  if (password !== "") {
@@ -112,6 +114,9 @@ export const uploadToRemote = async (
  if (isFolder && isRecursively) {
    throw Error("upload function doesn't implement recursive function yet!");
  } else if (isFolder && !isRecursively) {
+    if (uploadRaw) {
+      throw Error(`you specify uploadRaw, but you also provide a folder key!`);
+    }
    // folder
    const contentType = DEFAULT_CONTENT_TYPE;
    await s3Client.send(
@@ -133,7 +138,16 @@ export const uploadToRemote = async (
          mime.lookup(fileOrFolderPath) || DEFAULT_CONTENT_TYPE
        ) || DEFAULT_CONTENT_TYPE;
    }
-    const localContent = await vault.adapter.readBinary(fileOrFolderPath);
+    let localContent = undefined;
+    if (uploadRaw) {
+      if (typeof rawContent === "string") {
+        localContent = new TextEncoder().encode(rawContent);
+      } else {
+        localContent = rawContent;
+      }
+    } else {
+      localContent = await vault.adapter.readBinary(fileOrFolderPath);
+    }
    let remoteContent = localContent;
    if (password !== "") {
      remoteContent = await encryptArrayBuffer(localContent, password);
@@ -252,11 +266,14 @@ export const downloadFromRemote = async (
  vault: Vault,
  mtime: number,
  password: string = "",
-  remoteEncryptedKey: string = ""
+  remoteEncryptedKey: string = "",
+  skipSaving: boolean = false
 ) => {
  const isFolder = fileOrFolderPath.endsWith("/");

-  await mkdirpInVault(fileOrFolderPath, vault);
+  if (!skipSaving) {
+    await mkdirpInVault(fileOrFolderPath, vault);
+  }

  // the file is always local file
  // we need to encrypt it
@@ -264,6 +281,7 @@ export const downloadFromRemote = async (
  if (isFolder) {
    // mkdirp locally is enough
    // do nothing here
+    return new ArrayBuffer(0);
  } else {
    let downloadFile = fileOrFolderPath;
    if (password !== "") {
@@ -278,9 +296,12 @@ export const downloadFromRemote = async (
    if (password !== "") {
      localContent = await decryptArrayBuffer(remoteContent, password);
    }
-    await vault.adapter.writeBinary(fileOrFolderPath, localContent, {
-      mtime: mtime,
-    });
+    if (!skipSaving) {
+      await vault.adapter.writeBinary(fileOrFolderPath, localContent, {
+        mtime: mtime,
+      });
+    }
+    return localContent;
  }
 };

@@ -138,7 +138,9 @@ export const uploadToRemote = async (
  vault: Vault,
  isRecursively: boolean = false,
  password: string = "",
-  remoteEncryptedKey: string = ""
+  remoteEncryptedKey: string = "",
+  uploadRaw: boolean = false,
+  rawContent: string | ArrayBuffer = ""
 ) => {
  await client.init();
  let uploadFile = fileOrFolderPath;
@@ -152,6 +154,9 @@ export const uploadToRemote = async (
  if (isFolder && isRecursively) {
    throw Error("upload function doesn't implement recursive function yet!");
  } else if (isFolder && !isRecursively) {
+    if (uploadRaw) {
+      throw Error(`you specify uploadRaw, but you also provide a folder key!`);
+    }
    // folder
    if (password === "") {
      // if not encrypted, mkdir a remote folder
@@ -174,7 +179,16 @@ export const uploadToRemote = async (
  } else {
    // file
    // we ignore isRecursively parameter here
-    const localContent = await vault.adapter.readBinary(fileOrFolderPath);
+    let localContent = undefined;
+    if (uploadRaw) {
+      if (typeof rawContent === "string") {
+        localContent = new TextEncoder().encode(rawContent);
+      } else {
+        localContent = rawContent;
+      }
+    } else {
+      localContent = await vault.adapter.readBinary(fileOrFolderPath);
+    }
    let remoteContent = localContent;
    if (password !== "") {
      remoteContent = await encryptArrayBuffer(localContent, password);
@@ -277,13 +291,16 @@ export const downloadFromRemote = async (
  vault: Vault,
  mtime: number,
  password: string = "",
-  remoteEncryptedKey: string = ""
+  remoteEncryptedKey: string = "",
+  skipSaving: boolean = false
 ) => {
  await client.init();

  const isFolder = fileOrFolderPath.endsWith("/");

-  await mkdirpInVault(fileOrFolderPath, vault);
+  if (!skipSaving) {
+    await mkdirpInVault(fileOrFolderPath, vault);
+  }

  // the file is always local file
  // we need to encrypt it
@@ -291,6 +308,7 @@ export const downloadFromRemote = async (
  if (isFolder) {
    // mkdirp locally is enough
    // do nothing here
+    return new ArrayBuffer(0);
  } else {
    let downloadFile = fileOrFolderPath;
    if (password !== "") {
@@ -302,9 +320,12 @@ export const downloadFromRemote = async (
    if (password !== "") {
      localContent = await decryptArrayBuffer(remoteContent, password);
    }
-    await vault.adapter.writeBinary(fileOrFolderPath, localContent, {
-      mtime: mtime,
-    });
+    if (!skipSaving) {
+      await vault.adapter.writeBinary(fileOrFolderPath, localContent, {
+        mtime: mtime,
+      });
+    }
+    return localContent;
  }
 };

@@ -0,0 +1,68 @@
+import { App, Modal, Notice, PluginSettingTab, Setting } from "obsidian";
+import type RemotelySavePlugin from "./main"; // unavoidable
+import * as origLog from "loglevel";
+const log = origLog.getLogger("rs-default");
+
+export class SyncAlgoV2Modal extends Modal {
+  agree: boolean;
+  readonly plugin: RemotelySavePlugin;
+  constructor(app: App, plugin: RemotelySavePlugin) {
+    super(app);
+    this.plugin = plugin;
+    this.agree = false;
+  }
+  onOpen() {
+    let { contentEl } = this;
+    contentEl.createEl("h2", {
+      text: "Remotely Save has a better sync algorithm",
+    });
+
+    const texts = [
+      "Welcome to use Remotely Save!",
+
+      "From this version 0.3.0, a new algorithm has been developed, but it needs uploading extra meta data files _remotely-save-metadata-on-remote.{json,bin} to YOUR configured cloud destinations, besides your notes.",
+
+      "So that, for example, the second device can know that what files/folders have been deleted on the first device by reading those files.",
+
+      'If you agree, plase click the button "agree", and enjoy the plugin! AND PLEASE REMEMBER TO BACKUP YOUR VAULT FIRSTLY!',
+
+      'If you do not agree, you should stop using the current and later versions of Remotely Save. You could consider manually install the old version 0.2.14 which uses old algorithm and does not upload any extra meta data files. By clicking the "Do not agree" button, the plugin will unload itself, and you need to manually disable it in Obsidian settings.',
+    ];
+
+    const ul = contentEl.createEl("ul");
+
+    for (const t of texts) {
+      ul.createEl("li", {
+        text: t,
+      });
+    }
+
+    new Setting(contentEl)
+      .addButton((button) => {
+        button.setButtonText("Agree");
+        button.onClick(async () => {
+          this.agree = true;
+          this.close();
+        });
+      })
+      .addButton((button) => {
+        button.setButtonText("Do not agree");
+        button.onClick(() => {
+          this.close();
+        });
+      });
+  }
+
+  onClose() {
+    let { contentEl } = this;
+    contentEl.empty();
+    if (this.agree) {
+      log.info("agree to use the new algorithm");
+      this.plugin.saveAgreeToUseNewSyncAlgorithm();
+      this.plugin.enableAutoSyncIfSet();
+    } else {
+      log.info("do not agree to use the new algorithm");
+      this.plugin.unload();
+    }
+  }
+}