gristlabs_grist-core/app/client/models/QuerySet.ts

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/**
* A QuerySet represents a data query to the server, which returns matching data and includes a
* subscription. The subscription tells the server to send us docActions that affect this query.
*
* This file combines several classes related to it:
*
* - QuerySetManager is maintained by GristDoc, and keeps all active QuerySets for this doc.
* A new one is created using QuerySetManager.useQuerySet(owner, query)
*
* This creates a subscription to the server, and sets up owner.autoDispose() to clean up
* that subscription. If a subscription already exists, it only returns a reference to it,
* and disposal will remove the reference, only unsubscribing from the server when no
* referernces remain.
*
* - DynamicQuerySet is used by BaseView (in place of FilteredRowSource used previously). It is a
* single RowSource which mirrors a QuerySet, and allows the QuerySet to be changed.
* You set it to a new query using DynamicQuerySet.makeQuery(...)
*
* - QuerySet represents the actual query, makes the calls to the server to populate the data in
* the relevant TableData. It is also a FilteredRowSource for the rows matching the query.
*
* - TableQuerySets is a simple set of queries maintained for a single table (by DataTableModel).
* It's needed to know which rows are still relevant after a QuerySet is disposed.
*
* TODO: need to have a fetch limit (e.g. 1000 by default, or an option for user)
* TODO: client-side should show "..." or "50000 more rows not shown" in that case.
* TODO: Reference columns don't work properly because always use a displayCol which relies on formulas
*/
import * as DataTableModel from 'app/client/models/DataTableModel';
import {DocModel} from 'app/client/models/DocModel';
import {BaseFilteredRowSource, FilterFunc, RowId, RowList, RowSource} from 'app/client/models/rowset';
import {TableData} from 'app/client/models/TableData';
import {ActiveDocAPI, Query} from 'app/common/ActiveDocAPI';
import {TableDataAction} from 'app/common/DocActions';
import {DocData} from 'app/common/DocData';
import {nativeCompare} from 'app/common/gutil';
import {IRefCountSub, RefCountMap} from 'app/common/RefCountMap';
import {TableData as BaseTableData} from 'app/common/TableData';
import {tbind} from 'app/common/tbind';
import {Disposable, Holder, IDisposableOwnerT} from 'grainjs';
import * as ko from 'knockout';
import debounce = require('lodash/debounce');
// Limit on the how many rows to request for OnDemand tables.
const ON_DEMAND_ROW_LIMIT = 10000;
// Copied from app/server/lib/DocStorage.js. Actually could be 999, we are just playing it safe.
const MAX_SQL_PARAMS = 500;
/**
* A representation of a Query that uses tableRef/colRefs (i.e. metadata rowIds) to remain stable
* across table/column renames.
*/
export interface QueryRefs {
tableRef: number;
filterPairs: Array<[number, any[]]>;
}
/**
* QuerySetManager keeps track of all queries for a GristDoc instance. It is also responsible for
* disposing all state associated with queries when a GristDoc is disposed.
*
* Note that queries are made using tableId + colIds, which is a more suitable interface for a
* (future) public API, and easier to interact with DocData/TableData. However, it creates
* problems when tables or columns are renamed or deleted.
*
* To handle renames, we keep track of queries using their QueryRef representation, using
* tableRef/colRefs, i.e. metadata rowIds that aren't affected by renames.
*
* To handle deletes, we subscribe to isDeleted() observables of the needed tables and columns,
* and purge the query from QuerySetManager if any isDeleted() flag becomes true.
*/
export class QuerySetManager extends Disposable {
private _queryMap: RefCountMap<string, QuerySet>;
constructor(private _docModel: DocModel, docComm: ActiveDocAPI) {
super();
this._queryMap = this.autoDispose(new RefCountMap<string, QuerySet>({
create: (query: string) => QuerySet.create(null, _docModel, docComm, query, this),
dispose: (query: string, querySet: QuerySet) => querySet.dispose(),
gracePeriodMs: 60000, // Dispose after a minute of disuse.
}));
}
public useQuerySet(owner: IDisposableOwnerT<IRefCountSub<QuerySet>>, query: Query): QuerySet {
// Convert the query to a string key which identifies it.
const queryKey: string = encodeQuery(convertQueryToRefs(this._docModel, query));
// Look up or create the query in the RefCountMap. The returned object is a RefCountSub
// subscription, which decrements reference count when disposed.
const querySetRefCount = this._queryMap.use(queryKey);
// The passed-in owner is what will dispose this subscription (decrement reference count).
owner.autoDispose(querySetRefCount);
return querySetRefCount.get();
}
public purgeKey(queryKey: string) {
this._queryMap.purgeKey(queryKey);
}
// For testing: set gracePeriodMs, returning the previous value.
public testSetGracePeriodMs(ms: number): number {
return this._queryMap.testSetGracePeriodMs(ms);
}
}
/**
* DynamicQuerySet wraps one QuerySet, and allows changing it on the fly. It serves as a
* RowSource.
*/
export class DynamicQuerySet extends RowSource {
// Holds a reference to the currently active QuerySet.
private _holder = Holder.create<IRefCountSub<QuerySet>>(this);
// Shortcut to _holder.get().get().
private _querySet?: QuerySet;
// We could switch between several different queries quickly. If several queries are done
// fetching at the same time (e.g. were already ready), debounce lets us only update the
// query-set once to the last query.
private _updateQuerySetDebounced = debounce(tbind(this._updateQuerySet, this), 0);
constructor(private _querySetManager: QuerySetManager, private _tableModel: DataTableModel) {
super();
}
public getAllRows(): RowList {
return this._querySet ? this._querySet.getAllRows() : [];
}
public getNumRows(): number {
return this._querySet ? this._querySet.getNumRows() : 0;
}
/**
* Tells whether the query's result got truncated, i.e. not all rows are included.
*/
public get isTruncated(): boolean {
return this._querySet ? this._querySet.isTruncated : false;
}
/**
* Replace the query represented by this DynamicQuerySet. If multiple makeQuery() calls are made
* quickly (while waiting for the server), cb() may only be called for the latest one.
*
* If there is an error fetching data, cb(err) will be called with that error. The second
* argument to cb() is true if any data was changed, and false if not. Note that for a series of
* makeQuery() calls, cb() is always called at least once, and always asynchronously.
*/
public makeQuery(filters: {[colId: string]: any[]}, cb: (err: Error|null, changed: boolean) => void): void {
const query: Query = {tableId: this._tableModel.tableData.tableId, filters};
const newQuerySet = this._querySetManager.useQuerySet(this._holder, query);
// CB should be called asynchronously, since surprising hard-to-debug interactions can happen
// if it's sometimes synchronous and sometimes not.
newQuerySet.fetchPromise.then(() => {
this._updateQuerySetDebounced(newQuerySet, cb);
})
.catch((err) => { cb(err, false); });
}
private _updateQuerySet(nextQuerySet: QuerySet, cb: (err: Error|null, changed: boolean) => void): void {
try {
if (nextQuerySet !== this._querySet) {
const oldQuerySet = this._querySet;
this._querySet = nextQuerySet;
if (oldQuerySet) {
this.stopListening(oldQuerySet, 'rowChange');
this.stopListening(oldQuerySet, 'rowNotify');
this.trigger('rowChange', 'remove', oldQuerySet.getAllRows());
}
this.trigger('rowChange', 'add', this._querySet.getAllRows());
this.listenTo(this._querySet, 'rowNotify', tbind(this.trigger, this, 'rowNotify'));
this.listenTo(this._querySet, 'rowChange', tbind(this.trigger, this, 'rowChange'));
}
cb(null, true);
} catch (err) {
cb(err, true);
}
}
}
/**
* Class representing a query, which knows how to fetch the data, an presents a RowSource with
* matching rows. It uses new Comm calls for onDemand tables, but for regular tables, fetching
* data uses the good old tableModel.fetch(). In in most cases the data is already available, so
* this class is little more than a FilteredRowSource.
*/
export class QuerySet extends BaseFilteredRowSource {
// A publicly exposed promise, which may be waited on in order to know that the data has
// arrived. Until then, the RowSource underlying this QuerySet is empty.
public readonly fetchPromise: Promise<void>;
// Whether the fetched result is considered incomplete, i.e. not all rows were fetched.
public isTruncated: boolean;
constructor(docModel: DocModel, docComm: ActiveDocAPI, queryKey: string, qsm: QuerySetManager) {
const queryRefs: QueryRefs = decodeQuery(queryKey);
const query: Query = convertQueryFromRefs(docModel, queryRefs);
super(getFilterFunc(docModel.docData, query));
this.isTruncated = false;
// When table or any needed columns are deleted, purge this QuerySet from the map.
const isInvalid = this.autoDispose(makeQueryInvalidComputed(docModel, queryRefs));
this.autoDispose(isInvalid.subscribe((invalid) => {
if (invalid) { qsm.purgeKey(queryKey); }
}));
// Find the relevant DataTableModel.
const tableModel = docModel.dataTables[query.tableId];
// The number of values across all filters is limited to MAX_SQL_PARAMS. Normally a query has
// a single filter column, but in case there are multiple we divide the limit across all
// columns. It's OK to modify the query in place, since this modified version is not used
// elsewhere.
// (It might be better to limit this in DocStorage.js, but by limiting here, it's easier to
// know when to set isTruncated flag, to inform the user that data is incomplete.)
const colIds = Object.keys(query.filters);
if (colIds.length > 0) {
const maxParams = Math.floor(MAX_SQL_PARAMS / colIds.length);
for (const c of colIds) {
const values = query.filters[c];
if (values.length > maxParams) {
query.filters[c] = values.slice(0, maxParams);
this.isTruncated = true;
}
}
}
let fetchPromise: Promise<void>;
if (tableModel.tableMetaRow.onDemand()) {
const tableQS = tableModel.tableQuerySets;
fetchPromise = docComm.useQuerySet({limit: ON_DEMAND_ROW_LIMIT, ...query}).then((data) => {
// We assume that if we fetched the max number of rows, that there are likely more and the
// result should be reported as truncated.
// TODO: Better to fetch ON_DEMAND_ROW_LIMIT + 1 and omit one of them, so that isTruncated
// is only set if the row limit really was exceeded.
const rowIds = data.tableData[2];
if (rowIds.length >= ON_DEMAND_ROW_LIMIT) {
this.isTruncated = true;
}
this.onDispose(() => {
docComm.disposeQuerySet(data.querySubId).catch((err) => {
// tslint:disable-next-line:no-console
console.log(`Promise rejected for disposeQuerySet: ${err.message}`);
});
tableQS.removeQuerySet(this);
});
tableQS.addQuerySet(this, data.tableData);
});
} else {
// For regular (small), we fetch in bulk (and do nothing if already fetched).
fetchPromise = tableModel.fetch(false);
}
// This is a FilteredRowSource; subscribe it to the underlying data once the fetch resolves.
this.fetchPromise = fetchPromise.then(() => this.subscribeTo(tableModel));
}
}
/**
* Helper for use in a DataTableModel to maintain all QuerySets.
*/
export class TableQuerySets {
private _querySets: Set<QuerySet> = new Set();
constructor(private _tableData: TableData) {}
public addQuerySet(querySet: QuerySet, data: TableDataAction): void {
this._querySets.add(querySet);
this._tableData.loadPartial(data);
}
// Returns a Set of unused RowIds from querySet.
public removeQuerySet(querySet: QuerySet): void {
this._querySets.delete(querySet);
// Figure out which rows are not used by any other QuerySet in this DataTableModel.
const unusedRowIds = new Set(querySet.getAllRows());
for (const qs of this._querySets) {
for (const rowId of qs.getAllRows()) {
unusedRowIds.delete(rowId);
}
}
this._tableData.unloadPartial(Array.from(unusedRowIds) as number[]);
}
}
/**
* Returns a filtering function which tells whether a row matches the given query.
*/
export function getFilterFunc(docData: DocData, query: Query): FilterFunc {
// NOTE we rely without checking on tableId and colIds being valid.
const tableData: BaseTableData = docData.getTable(query.tableId)!;
const colIds = Object.keys(query.filters).sort();
const colPairs = colIds.map(
(c) => [tableData.getRowPropFunc(c)!, new Set(query.filters[c])] as [RowPropFunc, Set<any>]);
return (rowId: RowId) => colPairs.every(([getter, values]) => values.has(getter(rowId)));
}
type RowPropFunc = (rowId: RowId) => any;
/**
* Helper that converts a Query (with tableId/colIds) to an object with tableRef/colRefs (i.e.
* rowIds), and consistently sorted. We use that to identify a Query across table/column renames.
*/
function convertQueryToRefs(docModel: DocModel, query: Query): QueryRefs {
const tableRec: any = docModel.dataTables[query.tableId].tableMetaRow;
const colRefsByColId: {[colId: string]: number} = {};
for (const col of tableRec.columns.peek().peek()) {
colRefsByColId[col.colId.peek()] = col.getRowId();
}
const colIds = Object.keys(query.filters);
const filterPairs = colIds.map((c) => [colRefsByColId[c], query.filters[c]] as [number, any]);
// Keep filters sorted by colRef, for consistency.
filterPairs.sort((a, b) => nativeCompare(a[0], b[0]));
// Keep filter values sorted by value, for consistency.
filterPairs.forEach(([colRef, values]) => values.sort(nativeCompare));
return {tableRef: tableRec.getRowId(), filterPairs};
}
/**
* Helper to convert a QueryRefs (using tableRef/colRefs) object back to a Query (using
* tableId/colIds).
*/
function convertQueryFromRefs(docModel: DocModel, queryRefs: QueryRefs): Query {
const tableRec = docModel.dataTablesByRef.get(queryRefs.tableRef)!.tableMetaRow;
const filters: {[colId: string]: any[]} = {};
for (const [colRef, values] of queryRefs.filterPairs) {
filters[docModel.columns.getRowModel(colRef).colId.peek()] = values;
}
return {tableId: tableRec.tableId.peek(), filters};
}
/**
* Encodes a query (converted to QueryRefs using convertQueryToRefs()) as a string, to be usable
* as a key into a map.
*
* It uses JSON.stringify, but avoids objects since their order of keys in serialization is not
* guaranteed. This is important to produce consistent results (same query => same encoding).
*/
function encodeQuery(queryRefs: QueryRefs): string {
return JSON.stringify([queryRefs.tableRef, queryRefs.filterPairs]);
}
// Decode an encoded QueryRefs.
function decodeQuery(queryKey: string): QueryRefs {
const [tableRef, filterPairs] = JSON.parse(queryKey);
return {tableRef, filterPairs};
}
/**
* Returns a ko.computed() which turns to true when the table or any of the columns needed by the
* given query are deleted.
*/
function makeQueryInvalidComputed(docModel: DocModel, queryRefs: QueryRefs): ko.Computed<boolean> {
const tableFlag: ko.Observable<boolean> = docModel.tables.getRowModel(queryRefs.tableRef)._isDeleted;
const colFlags: Array<ko.Observable<boolean>> = queryRefs.filterPairs.map(
([colRef, values]) => docModel.columns.getRowModel(colRef)._isDeleted);
return ko.computed(() => Boolean(tableFlag() || colFlags.some((c) => c())));
}