Merge pull request #57 from dhilt/issue-56-pause-resume-methods

Pause/resume methods

package.json

@@ -1,6 +1,6 @@
 {
   "name": "vscroll",
-  "version": "1.6.0-beta.3",
+  "version": "1.6.0",
   "description": "Virtual scroll engine",
   "main": "dist/bundles/vscroll.umd.js",
   "module": "dist/bundles/vscroll.esm5.js",

src/classes/adapter.ts

@@ -2,7 +2,13 @@ import { Logger } from './logger';
 import { Buffer } from './buffer';
 import { Reactive } from './reactive';
 import {
-  AdapterPropName, AdapterPropType, EMPTY_ITEM, getDefaultAdapterProps, methodPreResult, reactiveConfigStorage
+  AdapterPropName,
+  AdapterPropType,
+  EMPTY_ITEM,
+  getDefaultAdapterProps,
+  methodPausedResult,
+  methodPreResult,
+  reactiveConfigStorage
 } from './adapter/props';
 import { wantedUtils } from './adapter/wanted';
 import { Viewport } from './viewport';
@@ -42,9 +48,10 @@ type InitializationParams<Item> = {
 }
 
 const ADAPTER_PROPS_STUB = getDefaultAdapterProps();
+const ALLOWED_METHODS_WHEN_PAUSED = ADAPTER_PROPS_STUB.filter(v => !!v.allowedWhenPaused).map(v => v.name);
 
 const _has = (obj: unknown, prop: string): boolean =>
-  typeof obj === 'object' && obj !== null && Object.prototype.hasOwnProperty.call(obj, prop);
+  !!obj && typeof obj === 'object' && Object.prototype.hasOwnProperty.call(obj, prop);
 
 const convertAppendArgs = <Item>(prepend: boolean, options: unknown, eof?: boolean) => {
   let result = options as AdapterAppendOptions<Item> & AdapterPrependOptions<Item>;
@@ -107,20 +114,38 @@ export class Adapter<Item = unknown> implements IAdapter<Item> {
   bof$: Reactive<boolean>;
   eof: boolean;
   eof$: Reactive<boolean>;
+  paused: boolean;
+  paused$: Reactive<boolean>;
 
   private relax$: Reactive<AdapterMethodResult> | null;
   private relaxRun: Promise<AdapterMethodResult> | null;
 
-  private getPromisifiedMethod(method: MethodResolver, defaultMethod: MethodResolver) {
+  private shouldIgnorePausedMethod(method: MethodResolver) {
+    const methodName = method.name as AdapterPropName;
+    return this.paused && !ALLOWED_METHODS_WHEN_PAUSED.includes(methodName);
+  }
+
+  private getPausedMethodResult(method: MethodResolver) {
+    this.logger?.log?.(() => 'scroller is paused: ' + method.name + ' method is ignored');
+    return Promise.resolve(methodPausedResult);
+  }
+
+  private getPromisifiedMethod(method: MethodResolver, args: unknown[]) {
+    return new Promise<AdapterMethodResult>(resolve => {
+      if (this.relax$) {
+        this.relax$.once(value => resolve(value));
+      }
+      method.apply(this, args);
+    });
+  }
+
+  private getWorkflowRunnerMethod(method: MethodResolver, defaultMethod: MethodResolver) {
     return (...args: unknown[]): Promise<AdapterMethodResult> =>
-      this.relax$
-        ? new Promise(resolve => {
-          if (this.relax$) {
-            this.relax$.once(value => resolve(value));
-          }
-          method.apply(this, args);
-        })
-        : defaultMethod.apply(this, args);
+      !this.relax$
+        ? defaultMethod.apply(this, args)
+        : this.shouldIgnorePausedMethod(method)
+          ? this.getPausedMethodResult(method)
+          : this.getPromisifiedMethod(method, args);
   }
 
   constructor(context: IAdapter<Item> | null, getWorkflow: WorkflowGetter<Item>, logger: Logger) {
@@ -249,7 +274,7 @@ export class Adapter<Item = unknown> implements IAdapter<Item> {
         if (type === AdapterPropType.Function) {
           value = (value as () => void).bind(this);
         } else if (type === AdapterPropType.WorkflowRunner) {
-          value = this.getPromisifiedMethod(value as MethodResolver, defaultValue as MethodResolver);
+          value = this.getWorkflowRunnerMethod(value as MethodResolver, defaultValue as MethodResolver);
         } else if (type === AdapterPropType.Reactive && reactivePropsStore[name]) {
           value = (context as IAdapter)[name];
         } else if (name === AdapterPropName.augmented) {
@@ -303,6 +328,8 @@ export class Adapter<Item = unknown> implements IAdapter<Item> {
     state.cycle.innerLoop.busy.on(busy => this.loopPending = busy);
     this.isLoading = state.cycle.busy.get();
     state.cycle.busy.on(busy => this.isLoading = busy);
+    this.paused = state.paused.get();
+    state.paused.on(paused => this.paused = paused);
 
     //viewport
     this.setFirstOrLastVisible = ({ first, last, workflow }) => {
@@ -501,6 +528,25 @@ export class Adapter<Item = unknown> implements IAdapter<Item> {
     });
   }
 
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  pause(): any {
+    this.logger.logAdapterMethod('pause');
+    this.workflow.call({
+      process: AdapterProcess.pause,
+      status: ProcessStatus.start
+    });
+  }
+
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  resume(): any {
+    this.logger.logAdapterMethod('resume');
+    this.workflow.call({
+      process: AdapterProcess.pause,
+      status: ProcessStatus.start,
+      payload: { options: { resume: true } }
+    });
+  }
+
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   fix(options: AdapterFixOptions<Item>): any {
     this.logger.logAdapterMethod('fix', options);

src/classes/adapter/props.ts

@@ -25,6 +25,8 @@ export enum AdapterPropName {
   bof$ = 'bof$',
   eof = 'eof',
   eof$ = 'eof$',
+  paused = 'paused',
+  paused$ = 'paused$',
   reset = 'reset',
   reload = 'reload',
   append = 'append',
@@ -35,6 +37,8 @@ export enum AdapterPropName {
   insert = 'insert',
   replace = 'replace',
   update = 'update',
+  pause = 'pause',
+  resume = 'resume',
   fix = 'fix',
   relax = 'relax',
   showLog = 'showLog',
@@ -58,6 +62,12 @@ export const methodPreResult: AdapterMethodResult = {
   details: 'Adapter is not initialized'
 };
 
+export const methodPausedResult: AdapterMethodResult = {
+  immediate: true,
+  success: true,
+  details: 'Scroller is paused'
+};
+
 const noopWF = () => Promise.resolve(methodPreResult);
 
 const emptyPackageInfo: IPackages = {
@@ -173,10 +183,17 @@ export const getDefaultAdapterProps = (): IAdapterProp[] => [
     value: false,
     reactive: Name.eof$
   },
+  {
+    type: Type.Scalar,
+    name: Name.paused,
+    value: false,
+    reactive: Name.paused$
+  },
   {
     type: Type.WorkflowRunner,
     name: Name.reset,
-    value: noopWF
+    value: noopWF,
+    allowedWhenPaused: true
   },
   {
     type: Type.WorkflowRunner,
@@ -223,6 +240,17 @@ export const getDefaultAdapterProps = (): IAdapterProp[] => [
     name: Name.update,
     value: noopWF
   },
+  {
+    type: Type.WorkflowRunner,
+    name: Name.pause,
+    value: noopWF
+  },
+  {
+    type: Type.WorkflowRunner,
+    name: Name.resume,
+    value: noopWF,
+    allowedWhenPaused: true
+  },
   {
     type: Type.WorkflowRunner,
     name: Name.fix,
@@ -274,6 +302,11 @@ export const getDefaultAdapterProps = (): IAdapterProp[] => [
     type: Type.Reactive,
     name: Name.eof$,
     value: new Reactive<boolean>()
+  },
+  {
+    type: Type.Reactive,
+    name: Name.paused$,
+    value: new Reactive<boolean>()
   }
 ];
 

src/classes/state.ts

@@ -1,4 +1,5 @@
 import { Settings } from './settings';
+import { Reactive } from './reactive';
 import { WorkflowCycleModel } from './state/cycle';
 import { FetchModel } from './state/fetch';
 import { ClipModel } from './state/clip';
@@ -11,6 +12,7 @@ export class State implements IState {
   readonly packageInfo: IPackages;
   private settings: Settings;
   initTime: number;
+  paused: Reactive<boolean>;
 
   cycle: WorkflowCycleModel;
   fetch: FetchModel;
@@ -26,6 +28,7 @@ export class State implements IState {
     this.packageInfo = packageInfo;
     this.settings = settings;
     this.initTime = Number(new Date());
+    this.paused = new Reactive(false);
 
     this.cycle = new WorkflowCycleModel(this.settings.instanceIndex, state ? state.cycle : void 0);
     this.fetch = new FetchModel(settings.directionPriority);
@@ -80,6 +83,7 @@ export class State implements IState {
   dispose(): void {
     this.scroll.stop();
     this.cycle.dispose();
+    this.paused.dispose();
     this.endInnerLoop();
   }
 

src/inputs/adapter.ts

@@ -237,6 +237,7 @@ export const AdapterMethods: AdapterProcessMap<{ [key: string]: string }> = {
   [Process.insert]: AdapterInsertParams,
   [Process.replace]: AdapterReplaceParams,
   [Process.update]: AdapterUpdateParams,
+  [Process.pause]: AdapterNoParams,
   [Process.fix]: AdapterFixParams,
 };
 
@@ -251,5 +252,6 @@ export const ADAPTER_METHODS: AdapterProcessMap<ICommonProps<PropertyKey>> = {
   [Process.insert]: INSERT_METHOD_PARAMS,
   [Process.replace]: REPLACE_METHOD_PARAMS,
   [Process.update]: UPDATE_METHOD_PARAMS,
+  [Process.pause]: NO_METHOD_PARAMS,
   [Process.fix]: FIX_METHOD_PARAMS,
 };

src/interfaces/adapter.ts

@@ -38,6 +38,7 @@ export interface IAdapterProp {
   wanted?: boolean;
   onDemand?: boolean;
   permanent?: boolean;
+  allowedWhenPaused?: boolean;
 }
 
 export interface ItemAdapter<Data = unknown> {
@@ -157,6 +158,8 @@ export interface IAdapter<Data = unknown> {
   readonly bof$: Reactive<boolean>;
   readonly eof: boolean;
   readonly eof$: Reactive<boolean>;
+  readonly paused: boolean;
+  readonly paused$: Reactive<boolean>;
   reset(datasource?: IDatasourceOptional): MethodResult;
   reload(reloadIndex?: number | string): MethodResult;
   append(options: AdapterAppendOptions<Data>): MethodResult;
@@ -170,6 +173,8 @@ export interface IAdapter<Data = unknown> {
   insert(options: AdapterInsertOptions<Data>): MethodResult;
   replace(options: AdapterReplaceOptions<Data>): MethodResult;
   update(options: AdapterUpdateOptions<Data>): MethodResult;
+  pause(): MethodResult;
+  resume(): MethodResult;
   fix(options: AdapterFixOptions<Data>): MethodResult; // experimental
   relax(callback?: () => void): MethodResult;
   showLog(): void;

src/interfaces/state.ts

@@ -1,4 +1,5 @@
 import { Direction } from '../inputs/index';
+import { Reactive } from '../classes/reactive';
 import { WorkflowCycleModel } from '../classes/state/cycle';
 import { FetchModel } from '../classes/state/fetch';
 import { ClipModel } from '../classes/state/clip';
@@ -15,6 +16,7 @@ export interface ScrollEventData {
 export interface State {
   packageInfo: IPackages;
   initTime: number;
+  paused: Reactive<boolean>;
   cycle: WorkflowCycleModel;
   fetch: FetchModel;
   clip: ClipModel;

src/processes/adapter/pause.ts

@@ -0,0 +1,28 @@
+import { Scroller } from '../../scroller';
+import { BaseAdapterProcessFactory, AdapterProcess, ProcessStatus } from '../misc/index';
+
+export default class Pause extends BaseAdapterProcessFactory(AdapterProcess.pause) {
+
+  static run(scroller: Scroller, options?: { resume: boolean }): void {
+    const resume = !!options?.resume;
+
+    // pause branch
+    if (!resume && !scroller.state.paused.get()) {
+      scroller.logger.log('pause scroller');
+      scroller.state.paused.set(true);
+      scroller.workflow.call({
+        process: AdapterProcess.pause,
+        status: ProcessStatus.done
+      });
+      return;
+    }
+
+    scroller.logger.log('resume scroller');
+    scroller.state.paused.set(false);
+    scroller.workflow.call({
+      process: AdapterProcess.pause,
+      status: ProcessStatus.next
+    });
+  }
+
+}

src/processes/index.ts

@@ -9,6 +9,7 @@ import UserClip from './adapter/clip';
 import Insert from './adapter/insert';
 import Replace from './adapter/replace';
 import Update from './adapter/update';
+import Pause from './adapter/pause';
 import Fix from './adapter/fix';
 import Start from './start';
 import PreFetch from './preFetch';
@@ -24,7 +25,7 @@ import { CommonProcess, AdapterProcess, ProcessStatus } from './misc/enums';
 
 export {
   Init, Scroll,
-  Reset, Reload, Append, Check, Remove, UserClip, Insert, Replace, Update, Fix,
+  Reset, Reload, Append, Check, Remove, UserClip, Insert, Replace, Update, Pause, Fix,
   Start, PreFetch, Fetch, PostFetch, Render, PreClip, Clip, Adjust, End,
   CommonProcess, AdapterProcess, ProcessStatus,
 };

src/processes/misc/enums.ts

@@ -23,6 +23,7 @@ export enum AdapterProcess {
   update = 'adapter.update',
   clip = 'adapter.clip',
   insert = 'adapter.insert',
+  pause = 'adapter.pause',
   fix = 'adapter.fix',
 }
 

src/version.ts

@@ -1,4 +1,4 @@
 export default {
   name: 'vscroll',
-  version: '1.6.0-beta.3'
+  version: '1.6.0'
 };

src/workflow-transducer.ts

@@ -13,6 +13,7 @@ import {
   Insert,
   Replace,
   Update,
+  Pause,
   Fix,
   Start,
   PreFetch,
@@ -131,6 +132,14 @@ export const runStateMachine = ({
         run(Init)(process);
       }
       break;
+    case AdapterProcess.pause:
+      if (status === Status.start) {
+        run(Pause)(options);
+      }
+      if (status === Status.next) {
+        run(Init)(process);
+      }
+      break;
     case AdapterProcess.fix:
       if (status === Status.start) {
         run(Fix)(options);