ui/src/frontend/widgets/sql/table/state.ts - third_party/perfetto - Git at Google

 // Copyright (C) 2024 The Android Open Source Project
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //      http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 import {NUM, Row} from '../../../../trace_processor/query_result';
 import {
   tableColumnAlias,
   ColumnOrderClause,
   Filter,
   isSqlColumnEqual,
   SqlColumn,
   sqlColumnId,
   TableColumn,
   tableColumnId,
 } from './column';
 import {buildSqlQuery} from './query_builder';
 import {raf} from '../../../../core/raf_scheduler';
 import {SortDirection} from '../../../../base/comparison_utils';
 import {assertTrue} from '../../../../base/logging';
 import {SqlTableDescription} from './table_description';
 import {Trace} from '../../../../public/trace';

 const ROW_LIMIT = 100;

 interface Request {
   // Select statement, without the includes and the LIMIT and OFFSET clauses.
   selectStatement: string;
   // Query, including the LIMIT and OFFSET clauses.
   query: string;
   // Map of SqlColumn's id to the column name in the query.
   columns: {[key: string]: string};
 }

 // Result of the execution of the query.
 interface Data {
   // Rows to show, including pagination.
   rows: Row[];
   error?: string;
 }

 interface RowCount {
   // Total number of rows in view, excluding the pagination.
   // Undefined if the query returned an error.
   count: number;
   // Filters which were used to compute this row count.
   // We need to recompute the totalRowCount only when filters change and not
   // when the set of columns / order by changes.
   filters: Filter[];
 }

 function isFilterEqual(a: Filter, b: Filter) {
   return (
     a.op === b.op &&
     a.columns.length === b.columns.length &&
     a.columns.every((c, i) => isSqlColumnEqual(c, b.columns[i]))
   );
 }

 function areFiltersEqual(a: Filter[], b: Filter[]) {
   if (a.length !== b.length) return false;
   return a.every((f, i) => isFilterEqual(f, b[i]));
 }

 export class SqlTableState {
   private readonly additionalImports: string[];

   // Columns currently displayed to the user. All potential columns can be found `this.table.columns`.
   private columns: TableColumn[];
   private filters: Filter[];
   private orderBy: {
     column: TableColumn;
     direction: SortDirection;
   }[];
   private offset = 0;
   private request: Request;
   private data?: Data;
   private rowCount?: RowCount;

   constructor(
     readonly trace: Trace,
     readonly config: SqlTableDescription,
     private readonly args?: {
       initialColumns?: TableColumn[];
       additionalColumns?: TableColumn[];
       imports?: string[];
       filters?: Filter[];
       orderBy?: {
         column: TableColumn;
         direction: SortDirection;
       }[];
     },
   ) {
     this.additionalImports = args?.imports || [];

     this.filters = args?.filters || [];
     this.columns = [];

     if (args?.initialColumns !== undefined) {
       assertTrue(
         args?.additionalColumns === undefined,
         'Only one of `initialColumns` and `additionalColumns` can be set',
       );
       this.columns.push(...args.initialColumns);
     } else {
       for (const column of this.config.columns) {
         if (column instanceof TableColumn) {
           if (column.startsHidden !== true) {
             this.columns.push(column);
           }
         } else {
           const cols = column.initialColumns?.();
           for (const col of cols ?? []) {
             this.columns.push(col);
           }
         }
       }
       if (args?.additionalColumns !== undefined) {
         this.columns.push(...args.additionalColumns);
       }
     }

     this.orderBy = args?.orderBy ?? [];

     this.request = this.buildRequest();
     this.reload();
   }

   clone(): SqlTableState {
     return new SqlTableState(this.trace, this.config, {
       initialColumns: this.columns,
       imports: this.args?.imports,
       filters: this.filters,
       orderBy: this.orderBy,
     });
   }

   private getSQLImports() {
     const tableImports = this.config.imports || [];
     return [...tableImports, ...this.additionalImports]
       .map((i) => `INCLUDE PERFETTO MODULE ${i};`)
       .join('\n');
   }

   private getCountRowsSQLQuery(): string {
     return `
       ${this.getSQLImports()}

       ${this.getSqlQuery({count: 'COUNT()'})}
     `;
   }

   // Return a query which selects the given columns, applying the filters and ordering currently in effect.
   getSqlQuery(columns: {[key: string]: SqlColumn}): string {
     return buildSqlQuery({
       table: this.config.name,
       columns,
       filters: this.filters,
       orderBy: this.getOrderedBy(),
     });
   }

   // We need column names to pass to the debug track creation logic.
   private buildSqlSelectStatement(): {
     selectStatement: string;
     columns: {[key: string]: string};
   } {
     const columns: {[key: string]: SqlColumn} = {};
     // A set of columnIds for quick lookup.
     const sqlColumnIds: Set<string> = new Set();
     // We want to use the shortest posible name for each column, but we also need to mindful of potential collisions.
     // To avoid collisions, we append a number to the column name if there are multiple columns with the same name.
     const columnNameCount: {[key: string]: number} = {};

     const tableColumns: {column: TableColumn; name: string; alias: string}[] =
       [];

     for (const column of this.columns) {
       // If TableColumn has an alias, use it. Otherwise, use the column name.
       const name = tableColumnAlias(column);
       if (!(name in columnNameCount)) {
         columnNameCount[name] = 0;
       }

       // Note: this can break if the user specifies a column which ends with `__<number>`.
       // We intentionally use two underscores to avoid collisions and will fix it down the line if it turns out to be a problem.
       const alias = `${name}__${++columnNameCount[name]}`;
       tableColumns.push({column, name, alias});
     }

     for (const column of tableColumns) {
       const sqlColumn = column.column.primaryColumn();
       // If we have only one column with this name, we don't need to disambiguate it.
       if (columnNameCount[column.name] === 1) {
         columns[column.name] = sqlColumn;
       } else {
         columns[column.alias] = sqlColumn;
       }
       sqlColumnIds.add(sqlColumnId(sqlColumn));
     }

     // We are going to be less fancy for the dependendent columns can just always suffix them with a unique integer.
     let dependentColumnCount = 0;
     for (const column of tableColumns) {
       const dependentColumns =
         column.column.dependentColumns !== undefined
           ? column.column.dependentColumns()
           : {};
       for (const col of Object.values(dependentColumns)) {
         if (sqlColumnIds.has(sqlColumnId(col))) continue;
         const name = typeof col === 'string' ? col : col.column;
         const alias = `__${name}_${dependentColumnCount++}`;
         columns[alias] = col;
         sqlColumnIds.add(sqlColumnId(col));
       }
     }

     return {
       selectStatement: this.getSqlQuery(columns),
       columns: Object.fromEntries(
         Object.entries(columns).map(([key, value]) => [
           sqlColumnId(value),
           key,
         ]),
       ),
     };
   }

   getNonPaginatedSQLQuery(): string {
     return `
       ${this.getSQLImports()}

       ${this.buildSqlSelectStatement().selectStatement}
     `;
   }

   getPaginatedSQLQuery(): Request {
     return this.request;
   }

   canGoForward(): boolean {
     if (this.data === undefined) return false;
     return this.data.rows.length > ROW_LIMIT;
   }

   canGoBack(): boolean {
     if (this.data === undefined) return false;
     return this.offset > 0;
   }

   goForward() {
     if (!this.canGoForward()) return;
     this.offset += ROW_LIMIT;
     this.reload({offset: 'keep'});
   }

   goBack() {
     if (!this.canGoBack()) return;
     this.offset -= ROW_LIMIT;
     this.reload({offset: 'keep'});
   }

   getDisplayedRange(): {from: number; to: number} | undefined {
     if (this.data === undefined) return undefined;
     return {
       from: this.offset + 1,
       to: this.offset + Math.min(this.data.rows.length, ROW_LIMIT),
     };
   }

   private async loadRowCount(): Promise<RowCount | undefined> {
     const filters = Array.from(this.filters);
     const res = await this.trace.engine.query(this.getCountRowsSQLQuery());
     if (res.error() !== undefined) return undefined;
     return {
       count: res.firstRow({count: NUM}).count,
       filters: filters,
     };
   }

   private buildRequest(): Request {
     const {selectStatement, columns} = this.buildSqlSelectStatement();
     // We fetch one more row to determine if we can go forward.
     const query = `
       ${this.getSQLImports()}
       ${selectStatement}
       LIMIT ${ROW_LIMIT + 1}
       OFFSET ${this.offset}
     `;
     return {selectStatement, query, columns};
   }

   private async loadData(): Promise<Data> {
     const queryRes = await this.trace.engine.query(this.request.query);
     const rows: Row[] = [];
     for (const it = queryRes.iter({}); it.valid(); it.next()) {
       const row: Row = {};
       for (const column of queryRes.columns()) {
         row[column] = it.get(column);
       }
       rows.push(row);
     }

     return {
       rows,
       error: queryRes.error(),
     };
   }

   private async reload(params?: {offset: 'reset' | 'keep'}) {
     if ((params?.offset ?? 'reset') === 'reset') {
       this.offset = 0;
     }

     const newFilters = this.rowCount?.filters;
     const filtersMatch =
       newFilters && areFiltersEqual(newFilters, this.filters);
     this.data = undefined;
     const request = this.buildRequest();
     this.request = request;
     if (!filtersMatch) {
       this.rowCount = undefined;
     }

     // Schedule a full redraw to happen after a short delay (50 ms).
     // This is done to prevent flickering / visual noise and allow the UI to fetch
     // the initial data from the Trace Processor.
     // There is a chance that someone else schedules a full redraw in the
     // meantime, forcing the flicker, but in practice it works quite well and
     // avoids a lot of complexity for the callers.
     // 50ms is half of the responsiveness threshold (100ms):
     // https://web.dev/rail/#response-process-events-in-under-50ms
     setTimeout(() => raf.scheduleFullRedraw(), 50);

     if (!filtersMatch) {
       this.rowCount = await this.loadRowCount();
     }

     const data = await this.loadData();

     // If the request has changed since we started loading the data, do not update the state.
     if (this.request !== request) return;
     this.data = data;

     raf.scheduleFullRedraw();
   }

   getTotalRowCount(): number | undefined {
     return this.rowCount?.count;
   }

   getCurrentRequest(): Request {
     return this.request;
   }

   getDisplayedRows(): Row[] {
     return this.data?.rows || [];
   }

   getQueryError(): string | undefined {
     return this.data?.error;
   }

   isLoading() {
     return this.data === undefined;
   }

   addFilter(filter: Filter) {
     this.filters.push(filter);
     this.reload();
   }

   removeFilter(filter: Filter) {
     this.filters = this.filters.filter((f) => !isFilterEqual(f, filter));
     this.reload();
   }

   getFilters(): Filter[] {
     return this.filters;
   }

   sortBy(clause: {column: TableColumn; direction: SortDirection}) {
     // Remove previous sort by the same column.
     this.orderBy = this.orderBy.filter(
       (c) => tableColumnId(c.column) != tableColumnId(clause.column),
     );
     // Add the new sort clause to the front, so we effectively stable-sort the
     // data currently displayed to the user.
     this.orderBy.unshift(clause);
     this.reload();
   }

   unsort() {
     this.orderBy = [];
     this.reload();
   }

   isSortedBy(column: TableColumn): SortDirection | undefined {
     if (this.orderBy.length === 0) return undefined;
     if (tableColumnId(this.orderBy[0].column) !== tableColumnId(column)) {
       return undefined;
     }
     return this.orderBy[0].direction;
   }

   getOrderedBy(): ColumnOrderClause[] {
     const result: ColumnOrderClause[] = [];
     for (const orderBy of this.orderBy) {
       const sortColumns = orderBy.column.sortColumns?.() ?? [
         orderBy.column.primaryColumn(),
       ];
       for (const column of sortColumns) {
         result.push({column, direction: orderBy.direction});
       }
     }
     return result;
   }

   addColumn(column: TableColumn, index: number) {
     this.columns.splice(index + 1, 0, column);
     this.reload({offset: 'keep'});
   }

   hideColumnAtIndex(index: number) {
     const column = this.columns[index];
     this.columns.splice(index, 1);
     // We can only filter by the visibile columns to avoid confusing the user,
     // so we remove order by clauses that refer to the hidden column.
     this.orderBy = this.orderBy.filter(
       (c) => tableColumnId(c.column) !== tableColumnId(column),
     );
     // TODO(altimin): we can avoid the fetch here if the orderBy hasn't changed.
     this.reload({offset: 'keep'});
   }

   moveColumn(fromIndex: number, toIndex: number) {
     if (fromIndex === toIndex) return;
     const column = this.columns[fromIndex];
     this.columns.splice(fromIndex, 1);
     if (fromIndex < toIndex) {
       // We have deleted a column, therefore we need to adjust the target index.
       --toIndex;
     }
     this.columns.splice(toIndex, 0, column);
     raf.scheduleFullRedraw();
   }

   getSelectedColumns(): TableColumn[] {
     return this.columns;
   }
 }
	// Copyright (C) 2024 The Android Open Source Project
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	import {NUM, Row} from '../../../../trace_processor/query_result';
	import {
	tableColumnAlias,
	ColumnOrderClause,
	Filter,
	isSqlColumnEqual,
	SqlColumn,
	sqlColumnId,
	TableColumn,
	tableColumnId,
	} from './column';
	import {buildSqlQuery} from './query_builder';
	import {raf} from '../../../../core/raf_scheduler';
	import {SortDirection} from '../../../../base/comparison_utils';
	import {assertTrue} from '../../../../base/logging';
	import {SqlTableDescription} from './table_description';
	import {Trace} from '../../../../public/trace';

	const ROW_LIMIT = 100;

	interface Request {
	// Select statement, without the includes and the LIMIT and OFFSET clauses.
	selectStatement: string;
	// Query, including the LIMIT and OFFSET clauses.
	query: string;
	// Map of SqlColumn's id to the column name in the query.
	columns: {[key: string]: string};
	}

	// Result of the execution of the query.
	interface Data {
	// Rows to show, including pagination.
	rows: Row[];
	error?: string;
	}

	interface RowCount {
	// Total number of rows in view, excluding the pagination.
	// Undefined if the query returned an error.
	count: number;
	// Filters which were used to compute this row count.
	// We need to recompute the totalRowCount only when filters change and not
	// when the set of columns / order by changes.
	filters: Filter[];
	}

	function isFilterEqual(a: Filter, b: Filter) {
	return (
	a.op === b.op &&
	a.columns.length === b.columns.length &&
	a.columns.every((c, i) => isSqlColumnEqual(c, b.columns[i]))
	);
	}

	function areFiltersEqual(a: Filter[], b: Filter[]) {
	if (a.length !== b.length) return false;
	return a.every((f, i) => isFilterEqual(f, b[i]));
	}

	export class SqlTableState {
	private readonly additionalImports: string[];

	// Columns currently displayed to the user. All potential columns can be found `this.table.columns`.
	private columns: TableColumn[];
	private filters: Filter[];
	private orderBy: {
	column: TableColumn;
	direction: SortDirection;
	}[];
	private offset = 0;
	private request: Request;
	private data?: Data;
	private rowCount?: RowCount;

	constructor(
	readonly trace: Trace,
	readonly config: SqlTableDescription,
	private readonly args?: {
	initialColumns?: TableColumn[];
	additionalColumns?: TableColumn[];
	imports?: string[];
	filters?: Filter[];
	orderBy?: {
	column: TableColumn;
	direction: SortDirection;
	}[];
	},
	) {
	this.additionalImports = args?.imports \|\| [];

	this.filters = args?.filters \|\| [];
	this.columns = [];

	if (args?.initialColumns !== undefined) {
	assertTrue(
	args?.additionalColumns === undefined,
	'Only one of `initialColumns` and `additionalColumns` can be set',
	);
	this.columns.push(...args.initialColumns);
	} else {
	for (const column of this.config.columns) {
	if (column instanceof TableColumn) {
	if (column.startsHidden !== true) {
	this.columns.push(column);
	}
	} else {
	const cols = column.initialColumns?.();
	for (const col of cols ?? []) {
	this.columns.push(col);
	}
	}
	}
	if (args?.additionalColumns !== undefined) {
	this.columns.push(...args.additionalColumns);
	}
	}

	this.orderBy = args?.orderBy ?? [];

	this.request = this.buildRequest();
	this.reload();
	}

	clone(): SqlTableState {
	return new SqlTableState(this.trace, this.config, {
	initialColumns: this.columns,
	imports: this.args?.imports,
	filters: this.filters,
	orderBy: this.orderBy,
	});
	}

	private getSQLImports() {
	const tableImports = this.config.imports \|\| [];
	return [...tableImports, ...this.additionalImports]
	.map((i) => `INCLUDE PERFETTO MODULE ${i};`)
	.join('\n');
	}

	private getCountRowsSQLQuery(): string {
	return `
	${this.getSQLImports()}

	${this.getSqlQuery({count: 'COUNT()'})}
	`;
	}

	// Return a query which selects the given columns, applying the filters and ordering currently in effect.
	getSqlQuery(columns: {[key: string]: SqlColumn}): string {
	return buildSqlQuery({
	table: this.config.name,
	columns,
	filters: this.filters,
	orderBy: this.getOrderedBy(),
	});
	}

	// We need column names to pass to the debug track creation logic.
	private buildSqlSelectStatement(): {
	selectStatement: string;
	columns: {[key: string]: string};
	} {
	const columns: {[key: string]: SqlColumn} = {};
	// A set of columnIds for quick lookup.
	const sqlColumnIds: Set<string> = new Set();
	// We want to use the shortest posible name for each column, but we also need to mindful of potential collisions.
	// To avoid collisions, we append a number to the column name if there are multiple columns with the same name.
	const columnNameCount: {[key: string]: number} = {};

	const tableColumns: {column: TableColumn; name: string; alias: string}[] =
	[];

	for (const column of this.columns) {
	// If TableColumn has an alias, use it. Otherwise, use the column name.
	const name = tableColumnAlias(column);
	if (!(name in columnNameCount)) {
	columnNameCount[name] = 0;
	}

	// Note: this can break if the user specifies a column which ends with `__<number>`.
	// We intentionally use two underscores to avoid collisions and will fix it down the line if it turns out to be a problem.
	const alias = `${name}__${++columnNameCount[name]}`;
	tableColumns.push({column, name, alias});
	}

	for (const column of tableColumns) {
	const sqlColumn = column.column.primaryColumn();
	// If we have only one column with this name, we don't need to disambiguate it.
	if (columnNameCount[column.name] === 1) {
	columns[column.name] = sqlColumn;
	} else {
	columns[column.alias] = sqlColumn;
	}
	sqlColumnIds.add(sqlColumnId(sqlColumn));
	}

	// We are going to be less fancy for the dependendent columns can just always suffix them with a unique integer.
	let dependentColumnCount = 0;
	for (const column of tableColumns) {
	const dependentColumns =
	column.column.dependentColumns !== undefined
	? column.column.dependentColumns()
	: {};
	for (const col of Object.values(dependentColumns)) {
	if (sqlColumnIds.has(sqlColumnId(col))) continue;
	const name = typeof col === 'string' ? col : col.column;
	const alias = `__${name}_${dependentColumnCount++}`;
	columns[alias] = col;
	sqlColumnIds.add(sqlColumnId(col));
	}
	}

	return {
	selectStatement: this.getSqlQuery(columns),
	columns: Object.fromEntries(
	Object.entries(columns).map(([key, value]) => [
	sqlColumnId(value),
	key,
	]),
	),
	};
	}

	getNonPaginatedSQLQuery(): string {
	return `
	${this.getSQLImports()}

	${this.buildSqlSelectStatement().selectStatement}
	`;
	}

	getPaginatedSQLQuery(): Request {
	return this.request;
	}

	canGoForward(): boolean {
	if (this.data === undefined) return false;
	return this.data.rows.length > ROW_LIMIT;
	}

	canGoBack(): boolean {
	if (this.data === undefined) return false;
	return this.offset > 0;
	}

	goForward() {
	if (!this.canGoForward()) return;
	this.offset += ROW_LIMIT;
	this.reload({offset: 'keep'});
	}

	goBack() {
	if (!this.canGoBack()) return;
	this.offset -= ROW_LIMIT;
	this.reload({offset: 'keep'});
	}

	getDisplayedRange(): {from: number; to: number} \| undefined {
	if (this.data === undefined) return undefined;
	return {
	from: this.offset + 1,
	to: this.offset + Math.min(this.data.rows.length, ROW_LIMIT),
	};
	}

	private async loadRowCount(): Promise<RowCount \| undefined> {
	const filters = Array.from(this.filters);
	const res = await this.trace.engine.query(this.getCountRowsSQLQuery());
	if (res.error() !== undefined) return undefined;
	return {
	count: res.firstRow({count: NUM}).count,
	filters: filters,
	};
	}

	private buildRequest(): Request {
	const {selectStatement, columns} = this.buildSqlSelectStatement();
	// We fetch one more row to determine if we can go forward.
	const query = `
	${this.getSQLImports()}
	${selectStatement}
	LIMIT ${ROW_LIMIT + 1}
	OFFSET ${this.offset}
	`;
	return {selectStatement, query, columns};
	}

	private async loadData(): Promise<Data> {
	const queryRes = await this.trace.engine.query(this.request.query);
	const rows: Row[] = [];
	for (const it = queryRes.iter({}); it.valid(); it.next()) {
	const row: Row = {};
	for (const column of queryRes.columns()) {
	row[column] = it.get(column);
	}
	rows.push(row);
	}

	return {
	rows,
	error: queryRes.error(),
	};
	}

	private async reload(params?: {offset: 'reset' \| 'keep'}) {
	if ((params?.offset ?? 'reset') === 'reset') {
	this.offset = 0;
	}

	const newFilters = this.rowCount?.filters;
	const filtersMatch =
	newFilters && areFiltersEqual(newFilters, this.filters);
	this.data = undefined;
	const request = this.buildRequest();
	this.request = request;
	if (!filtersMatch) {
	this.rowCount = undefined;
	}

	// Schedule a full redraw to happen after a short delay (50 ms).
	// This is done to prevent flickering / visual noise and allow the UI to fetch
	// the initial data from the Trace Processor.
	// There is a chance that someone else schedules a full redraw in the
	// meantime, forcing the flicker, but in practice it works quite well and
	// avoids a lot of complexity for the callers.
	// 50ms is half of the responsiveness threshold (100ms):
	// https://web.dev/rail/#response-process-events-in-under-50ms
	setTimeout(() => raf.scheduleFullRedraw(), 50);

	if (!filtersMatch) {
	this.rowCount = await this.loadRowCount();
	}

	const data = await this.loadData();

	// If the request has changed since we started loading the data, do not update the state.
	if (this.request !== request) return;
	this.data = data;

	raf.scheduleFullRedraw();
	}

	getTotalRowCount(): number \| undefined {
	return this.rowCount?.count;
	}

	getCurrentRequest(): Request {
	return this.request;
	}

	getDisplayedRows(): Row[] {
	return this.data?.rows \|\| [];
	}

	getQueryError(): string \| undefined {
	return this.data?.error;
	}

	isLoading() {
	return this.data === undefined;
	}

	addFilter(filter: Filter) {
	this.filters.push(filter);
	this.reload();
	}

	removeFilter(filter: Filter) {
	this.filters = this.filters.filter((f) => !isFilterEqual(f, filter));
	this.reload();
	}

	getFilters(): Filter[] {
	return this.filters;
	}

	sortBy(clause: {column: TableColumn; direction: SortDirection}) {
	// Remove previous sort by the same column.
	this.orderBy = this.orderBy.filter(
	(c) => tableColumnId(c.column) != tableColumnId(clause.column),
	);
	// Add the new sort clause to the front, so we effectively stable-sort the
	// data currently displayed to the user.
	this.orderBy.unshift(clause);
	this.reload();
	}

	unsort() {
	this.orderBy = [];
	this.reload();
	}

	isSortedBy(column: TableColumn): SortDirection \| undefined {
	if (this.orderBy.length === 0) return undefined;
	if (tableColumnId(this.orderBy[0].column) !== tableColumnId(column)) {
	return undefined;
	}
	return this.orderBy[0].direction;
	}

	getOrderedBy(): ColumnOrderClause[] {
	const result: ColumnOrderClause[] = [];
	for (const orderBy of this.orderBy) {
	const sortColumns = orderBy.column.sortColumns?.() ?? [
	orderBy.column.primaryColumn(),
	];
	for (const column of sortColumns) {
	result.push({column, direction: orderBy.direction});
	}
	}
	return result;
	}

	addColumn(column: TableColumn, index: number) {
	this.columns.splice(index + 1, 0, column);
	this.reload({offset: 'keep'});
	}

	hideColumnAtIndex(index: number) {
	const column = this.columns[index];
	this.columns.splice(index, 1);
	// We can only filter by the visibile columns to avoid confusing the user,
	// so we remove order by clauses that refer to the hidden column.
	this.orderBy = this.orderBy.filter(
	(c) => tableColumnId(c.column) !== tableColumnId(column),
	);
	// TODO(altimin): we can avoid the fetch here if the orderBy hasn't changed.
	this.reload({offset: 'keep'});
	}

	moveColumn(fromIndex: number, toIndex: number) {
	if (fromIndex === toIndex) return;
	const column = this.columns[fromIndex];
	this.columns.splice(fromIndex, 1);
	if (fromIndex < toIndex) {
	// We have deleted a column, therefore we need to adjust the target index.
	--toIndex;
	}
	this.columns.splice(toIndex, 0, column);
	raf.scheduleFullRedraw();
	}

	getSelectedColumns(): TableColumn[] {
	return this.columns;
	}
	}