feat(shapefile): DBFArrowLoader

modules/core/test/lib/api/create-data-source.spec.ts

@@ -10,7 +10,7 @@ import {PMTilesSource} from '@loaders.gl/pmtiles';
 import {MVTSource, TableTileSource} from '@loaders.gl/mvt';
 import {_GeoJSONLoader as GeoJSONLoader} from '@loaders.gl/json';
 
-test.only('createDataSource', async (t) => {
+test('createDataSource', async (t) => {
   const dataSource = createDataSource(url, [PMTilesSource, TableTileSource, MVTSource], {
     pmtiles: {
       attributions: example.attributions,

modules/gis/src/lib/table-converters/make-arrow-batch-iterator.ts

@@ -0,0 +1,53 @@
+// loaders.gl
+// SPDX-License-Identifier: MIT
+// Copyright (c) vis.gl contributors
+
+import * as arrow from 'apache-arrow';
+import type {Table} from '@loaders.gl/schema';
+import {
+  convertSchemaToArrow,
+  getTableLength,
+  getTableNumCols,
+  getTableCellAt
+} from '@loaders.gl/schema-utils';
+
+export function* makeTableToArrowBatchesIterator(
+  table: Table,
+  options?: {batchSize?: number}
+): IterableIterator<arrow.RecordBatch> {
+  const arrowSchema = convertSchemaToArrow(table.schema!);
+
+  const length = getTableLength(table);
+  const numColumns = getTableNumCols(table);
+  const batchSize = options?.batchSize || length;
+
+  const builders = arrowSchema?.fields.map((arrowField) => arrow.makeBuilder(arrowField));
+  const structField = new arrow.Struct(arrowSchema.fields);
+
+  let batchLength = 0;
+  for (let rowIndex = 0; rowIndex < length; rowIndex++) {
+    for (let columnIndex = 0; columnIndex < numColumns; ++columnIndex) {
+      const value = getTableCellAt(table, rowIndex, columnIndex);
+
+      const builder = builders[columnIndex];
+      builder.append(value);
+      batchLength++;
+
+      if (batchLength >= batchSize) {
+        const datas = builders.map((builder) => builder.flush());
+        const structData = new arrow.Data(structField, 0, batchLength, 0, undefined, datas);
+        yield new arrow.RecordBatch(arrowSchema, structData);
+        batchLength = 0;
+      }
+    }
+  }
+
+  if (batchLength > 0) {
+    const datas = builders.map((builder) => builder.flush());
+    const structData = new arrow.Data(structField, 0, batchLength, 0, undefined, datas);
+    yield new arrow.RecordBatch(arrowSchema, structData);
+    batchLength = 0;
+  }
+
+  builders.map((builder) => builder.finish());
+}

modules/schema-utils/src/index.ts

@@ -126,8 +126,9 @@ export {
 } from './lib/table/arrow-api/index';
 
 // EXPERIMENTAL APIs
+export {ArrowTableBuilder} from './lib/table/batch-builder/arrow-table-builder';
 
-// SCHEMA UTILS
+// Schema utils
 export {getTypeInfo} from './lib/table/arrow-api/get-type-info';
 
 export {default as AsyncQueue} from './lib/utils/async-queue';

modules/schema-utils/src/lib/table/batch-builder/arrow-table-builder.ts

@@ -0,0 +1,113 @@
+// loaders.gl
+// SPDX-License-Identifier: MIT
+// Copyright (c) vis.gl contributors
+
+import type {Schema, ArrowTable, ArrowTableBatch} from '@loaders.gl/schema';
+import * as arrow from 'apache-arrow';
+import {convertSchemaToArrow} from '@loaders.gl/schema-utils';
+
+/** Builds an arrow table or batches */
+export class ArrowTableBuilder {
+  schema: Schema;
+  arrowSchema: arrow.Schema;
+  arrowBuilders: arrow.Builder[];
+  length: number;
+
+  constructor(schema: Schema) {
+    this.schema = schema;
+    this.arrowSchema = convertSchemaToArrow(schema);
+    this.arrowBuilders = this.arrowSchema.fields.map((field) =>
+      arrow.makeBuilder({type: field.type, nullValues: [null]})
+    );
+    this.length = 0;
+  }
+
+  addObjectRow(row: {[key: string]: any}) {
+    for (let i = 0; i < this.arrowBuilders.length; i++) {
+      const columnName = this.schema.fields[i].name;
+      const value = row[columnName];
+      // if (this.schema.fields[i].type.toString() === 'bool') {
+      //   debugger;
+      // }
+      this.arrowBuilders[i].append(value);
+    }
+    this.length++;
+  }
+
+  addArrayRow(row: any[]) {
+    for (let i = 0; i < this.arrowBuilders.length; i++) {
+      this.arrowBuilders[i].append(row[i]);
+    }
+    this.length++;
+  }
+
+  /** Makes sure that a first batch with schema is sent even if no rows */
+  firstBatch(): ArrowTableBatch | null {
+    const arrowRecordBatch = this._getArrowRecordBatch();
+    // If there is data, a batch will be sent later
+    if (arrowRecordBatch.numCols !== 0) {
+      return null;
+    }
+    return {
+      shape: 'arrow-table',
+      batchType: 'data',
+      length: arrowRecordBatch.numRows,
+      schema: this.schema,
+      data: new arrow.Table(arrowRecordBatch)
+    };
+  }
+
+  /** Flush the current batch if conditions are right */
+  flushBatch(): ArrowTableBatch | null {
+    const arrowRecordBatch = this._getArrowRecordBatch();
+    if (arrowRecordBatch.numCols === 0) {
+      return null;
+    }
+    return {
+      shape: 'arrow-table',
+      batchType: 'data',
+      length: arrowRecordBatch.numRows,
+      schema: this.schema,
+      data: new arrow.Table(arrowRecordBatch)
+    };
+  }
+
+  /** Get a last batch if any data is left */
+  finishBatch(): ArrowTableBatch | null {
+    const arrowRecordBatch = this._getArrowRecordBatch();
+    this.arrowBuilders.forEach((builder) => builder.finish());
+    if (arrowRecordBatch.numCols === 0) {
+      return null;
+    }
+    return {
+      shape: 'arrow-table',
+      batchType: 'data',
+      length: arrowRecordBatch.numRows,
+      schema: this.schema,
+      data: new arrow.Table(arrowRecordBatch)
+    };
+  }
+
+  /** Return a table with all the accumulated data */
+  finishTable(): ArrowTable {
+    const arrowRecordBatch = this._getArrowRecordBatch();
+    this.arrowBuilders.forEach((builder) => builder.finish());
+    return {
+      shape: 'arrow-table',
+      schema: this.schema,
+      data: new arrow.Table(arrowRecordBatch)
+    };
+  }
+
+  /** Extract a record batch flushing the currently accumulated data in the builders */
+  _getArrowRecordBatch(): arrow.RecordBatch {
+    const {arrowBuilders, arrowSchema} = this;
+    const arrowDatas = arrowBuilders.map((builder) => builder.flush());
+    arrowBuilders.forEach((builder) => builder.finish());
+
+    const structField = new arrow.Struct(arrowSchema.fields);
+    const arrowStructData = new arrow.Data(structField, 0, length, 0, undefined, arrowDatas);
+    const arrowRecordBatch = new arrow.RecordBatch(arrowSchema, arrowStructData);
+    return arrowRecordBatch;
+  }
+}

modules/shapefile/src/dbf-arrow-loader.ts

@@ -0,0 +1,46 @@
+// loaders.gl
+// SPDX-License-Identifier: MIT
+// Copyright (c) vis.gl contributors
+
+import type {Loader, LoaderWithParser, LoaderOptions} from '@loaders.gl/loader-utils';
+import type {ArrowTable, ArrowTableBatch} from '@loaders.gl/schema';
+import {parseDBF, parseDBFInBatches} from './lib/parsers/parse-dbf-to-arrow';
+import { DBFFormat } from './dbf-format';
+
+// __VERSION__ is injected by babel-plugin-version-inline
+// @ts-ignore TS2304: Cannot find name '__VERSION__'.
+const VERSION = typeof __VERSION__ !== 'undefined' ? __VERSION__ : 'latest';
+
+export type DBFLoaderOptions = LoaderOptions & {
+  dbf?: {
+    encoding?: string;
+    /** Override the URL to the worker bundle (by default loads from unpkg.com) */
+    workerUrl?: string;
+  };
+};
+
+/**
+ * DBFLoader - DBF files are used to contain non-geometry columns in Shapefiles
+ */
+export const DBFArrowWorkerLoader = {
+  ...DBFFormat,
+  dataType: null as unknown as ArrowTable,
+  batchType: null as unknown as ArrowTableBatch,
+  version: VERSION,
+  worker: true,
+  options: {
+    dbf: {
+      encoding: 'latin1'
+    }
+  }
+} as const satisfies Loader<ArrowTable, ArrowTableBatch, DBFLoaderOptions>;
+
+/** DBF file loader */
+export const DBFArrowLoader = {
+  ...DBFArrowWorkerLoader,
+  parse: async (arrayBuffer, options) => parseDBF(arrayBuffer, options),
+  parseSync: parseDBF,
+  parseInBatches(arrayBufferIterator: AsyncIterable<ArrayBuffer> | Iterable<ArrayBuffer>, options) {
+    return parseDBFInBatches(arrayBufferIterator, options);
+  }
+} as const satisfies LoaderWithParser<ArrowTable, ArrowTableBatch, DBFLoaderOptions>;

modules/shapefile/src/dbf-format.ts

@@ -0,0 +1,15 @@
+// loaders.gl
+// SPDX-License-Identifier: MIT
+// Copyright (c) vis.gl contributors
+
+import type {Format} from '@loaders.gl/loader-utils';
+
+/** Information about the DBF format */
+export const DBFFormat = {
+  name: 'DBF',
+  id: 'dbf',
+  module: 'shapefile',
+  category: 'table',
+  extensions: ['dbf'],
+  mimeTypes: ['application/x-dbf'],
+} as const satisfies Format;

modules/shapefile/src/index.ts

@@ -7,6 +7,7 @@ export {ShapefileLoader} from './shapefile-loader';
 
 export type {DBFLoaderOptions} from './dbf-loader';
 export {DBFLoader, DBFWorkerLoader} from './dbf-loader';
+export {DBFArrowLoader, DBFArrowWorkerLoader} from './dbf-arrow-loader';
 
 export type {SHPLoaderOptions} from './shp-loader';
 export {SHPLoader, SHPWorkerLoader} from './shp-loader';