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43 lines
1.5 KiB
43 lines
1.5 KiB
/**
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* Implements a cache of values computed from the data in a Grist column.
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*/
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import {TableData} from 'app/client/models/TableData';
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import {DocAction} from 'app/common/DocActions';
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import {isBulkUpdateRecord, isUpdateRecord} from 'app/common/DocActions';
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import {getSetMapValue} from 'app/common/gutil';
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export class ColumnCache<T> {
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private _cachedColIndexes = new Map<string, T>();
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constructor(private _tableData: TableData) {
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// Whenever a table action is applied, consider invalidating per-column caches.
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this._tableData.tableActionEmitter.addListener(this._invalidateCache, this);
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this._tableData.dataLoadedEmitter.addListener(this._clearCache, this);
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}
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/**
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* Returns the cached value for the given column, or calculates and caches the value using the
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* provided calc() function.
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*/
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public getValue(colId: string, calc: () => T): T {
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return getSetMapValue(this._cachedColIndexes, colId, calc);
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}
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private _invalidateCache(action: DocAction): void {
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if (isUpdateRecord(action) || isBulkUpdateRecord(action)) {
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// If the update only affects existing records, only invalidate affected columns.
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const colValues = action[3];
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for (const colId of Object.keys(colValues)) {
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this._cachedColIndexes.delete(colId);
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}
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} else {
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// For add/delete actions and all schema changes, drop the cache entirely to be on the safe side.
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this._clearCache();
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}
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}
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private _clearCache(): void {
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this._cachedColIndexes.clear();
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}
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}
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