(core) Adds setSelectedRows to the grist api for custom view

Summary:
This is needed to let custom widget driver filtering of other widget in the same page.

Descripion here:
 - https://grist.quip.com/ctytAQJoFMsM/Hopefully-Small-Projects#temp:C:NNCfe2030b27647439886ca83595

Test Plan: New api tested in a new nbrowser test

Reviewers: paulfitz

Reviewed By: paulfitz

Differential Revision: https://phab.getgrist.com/D3253

app/client/components/LinkingState.ts

@@ -10,7 +10,7 @@ import {ClientQuery, QueryOperation} from "app/common/ActiveDocAPI";
 import {isList, isRefListType} from "app/common/gristTypes";
 import * as gutil from "app/common/gutil";
 import {encodeObject} from 'app/plugin/objtypes';
-import {Disposable} from "grainjs";
+import {Disposable, toKo} from "grainjs";
 import * as  ko from "knockout";
 import mapValues = require('lodash/mapValues');
 import pickBy = require('lodash/pickBy');
@@ -87,7 +87,9 @@ export class LinkingState extends Disposable {
 
     if (tgtColId) {
       const operation = isRefListType(tgtCol.type()) ? 'intersects' : 'in';
-      if (srcColId) {
+      if (srcSection.parentKey() === 'custom') {
+        this.filterColValues = this._srcCustomFilter(tgtColId, operation);
+      } else if (srcColId) {
         this.filterColValues = this._srcCellFilter(tgtColId, operation);
       } else {
         this.filterColValues = this._simpleFilter(tgtColId, operation, (rowId => [rowId]));
@@ -122,6 +124,8 @@ export class LinkingState extends Disposable {
     } else if (isSummaryOf(tgtSection.table(), srcSection.table())) {
       // TODO: We should move the cursor, but don't currently it for summaries. For that, we need a
       // column or map representing the inverse of summary table's "group" column.
+    } else if (srcSection.parentKey() === 'custom') {
+      this.filterColValues = this._srcCustomFilter('id', 'in');
     } else {
       const srcValueFunc = srcColId ? this._makeSrcCellGetter() : identity;
       if (srcValueFunc) {
@@ -196,6 +200,14 @@ export class LinkingState extends Disposable {
     }
   }
 
+  // Value for this.filterColValues based on the values in srcSection.selectedRows
+  private _srcCustomFilter(colId: string, operation: QueryOperation): ko.Computed<FilterColValues> | undefined {
+    return this.autoDispose(ko.computed(() => {
+      const values = toKo(ko, this._srcSection.selectedRows)();
+      return {filters: {[colId]: values}, operations: {[colId]: operation}} as FilterColValues;
+    }));
+  }
+
   // Returns a function which returns the value of the cell
   // in srcCol in the selected record of srcSection.
   // Uses a row model to create a dependency on the cell's value,

app/client/components/WidgetFrame.ts

@@ -360,6 +360,14 @@ export class GristViewImpl implements GristView {
     return data;
   }
 
+  public async allowSelectBy(): Promise<void> {
+    this._baseView.viewSection.allowSelectBy.set(true);
+  }
+
+  public async setSelectedRows(rowIds: number[]): Promise<void> {
+    this._baseView.viewSection.selectedRows.set(rowIds);
+  }
+
   private _visibleColumns() {
     const columns: ColumnRec[] = this._baseView.viewSection.columns.peek();
     const hiddenCols = this._baseView.viewSection.hiddenColumns.peek().map(c => c.id.peek());

app/client/models/entities/ViewSectionRec.ts

@@ -22,7 +22,7 @@ import {arrayRepeat} from 'app/common/gutil';
 import {Sort} from 'app/common/SortSpec';
 import {ColumnsToMap, WidgetColumnMap} from 'app/plugin/CustomSectionAPI';
 import {ColumnToMapImpl} from 'app/client/models/ColumnToMap';
-import {Computed} from 'grainjs';
+import {Computed, Observable} from 'grainjs';
 import * as ko from 'knockout';
 import defaults = require('lodash/defaults');
 
@@ -159,6 +159,12 @@ export interface ViewSectionRec extends IRowModel<"_grist_Views_section"> {
   // Temporary variable holding widget desired access (changed either from manifest or via API).
   desiredAccessLevel: ko.Observable<AccessLevel|null>;
 
+  // Show widget as linking source. Used by custom widget.
+  allowSelectBy: Observable<boolean>;
+
+  // List of selected rows
+  selectedRows: Observable<number[]>;
+
   // Save all filters of fields/columns in the section.
   saveFilters(): Promise<void>;
 
@@ -562,4 +568,7 @@ export function createViewSectionRec(this: ViewSectionRec, docModel: DocModel):
     }
     return result;
   });
+
+  this.allowSelectBy = Observable.create(this, false);
+  this.selectedRows = Observable.create(this, []);
 }

app/client/ui/selectBy.ts

@@ -74,11 +74,24 @@ function isValidLink(source: LinkNode, target: LinkNode) {
     return false;
   }
 
-  // cannot select from chart or custom
-  if (['chart', 'custom'].includes(source.widgetType)) {
+  // cannot select from chart
+  if (source.widgetType === 'chart') {
     return false;
   }
 
+  if (source.widgetType === 'custom') {
+
+    // custom widget do not support linking by columns
+    if (source.tableId !== source.section.table.peek().primaryTableId.peek()) {
+      return false;
+    }
+
+    // custom widget must allow select by
+    if (!source.section.allowSelectBy.get()) {
+      return false;
+    }
+  }
+
   // The link must not create a cycle
   if (source.ancestors.has(target.section.getRowId())) {
     return false;