finos · texodus · Dec 28, 2018 · Dec 11, 2018 · Dec 21, 2018 · Dec 22, 2018
diff --git a/packages/perspective/src/js/DataAccessor/DataAccessor.js b/packages/perspective/src/js/DataAccessor/DataAccessor.js
@@ -0,0 +1,172 @@
+/******************************************************************************
+ *
+ * Copyright (c) 2018, the Perspective Authors.
+ *
+ * This file is part of the Perspective library, distributed under the terms of
+ * the Apache License 2.0.  The full license can be found in the LICENSE file.
+ *
+ */
+
+import {DateParser, is_valid_date} from "./DateParser.js";
+import {get_column_type} from "../utils.js";
+
+export class DataAccessor {
+    constructor() {
+        this.data_formats = {
+            row: 0,
+            column: 1,
+            schema: 2
+        };
+        this.format = undefined;
+        this.data = undefined;
+        this.names = undefined;
+        this.types = undefined;
+        this.row_count = undefined;
+        this.date_parsers = {};
+        this.date_validator = val => is_valid_date(val);
+    }
+
+    extract_typevec(typevec) {
+        let types = [];
+        for (let i = 0; i < typevec.size() - 1; i++) {
+            types.push(typevec.get(i));
+        }
+        return types;
+    }
+
+    is_format(data) {
+        if (Array.isArray(data)) {
+            return this.data_formats.row;
+        } else if (Array.isArray(data[Object.keys(data)[0]])) {
+            return this.data_formats.column;
+        } else if (typeof data[Object.keys(data)[0]] === "string" || typeof data[Object.keys(data)[0]] === "function") {
+            return this.data_formats.schema;
+        } else {
+            throw "Unknown data format!";
+        }
+    }
+
+    get_row_count(data) {
+        if (this.format === this.data_formats.row) {
+            return data.length;
+        } else if (this.format === this.data_formats.column) {
+            return data[Object.keys(data)[0]].length;
+        } else {
+            return 0;
+        }
+    }
+
+    get(column_name, row_index) {
+        let value = undefined;
+
+        if (this.format === this.data_formats.row) {
+            let d = this.data[row_index];
+            if (d.hasOwnProperty(column_name)) {
+                value = d[column_name];
+            }
+        } else if (this.format === this.data_formats.column) {
+            if (this.data.hasOwnProperty(column_name)) {
+                value = this.data[column_name][row_index];
+            }
+        } else if (this.format === this.data_formats.schema) {
+            value = undefined;
+        } else {
+            throw "Unknown data format!";
+        }
+
+        return value;
+    }
+
+    marshal(column_name, row_index, type) {
+        let val = clean_data(this.get(column_name, row_index));
+        let date_parser;
+
+        if (val === null) {
+            return null;
+        }
+
+        if (typeof val === "undefined") {
+            return undefined;
+        }
+
+        if (this.date_parsers[column_name] === undefined) {
+            this.date_parsers[column_name] = new DateParser();
+        }
+
+        date_parser = this.date_parsers[column_name];
+
+        switch (get_column_type(type.value)) {
+            case "float":
+            case "integer": {
+                val = Number(val);
+                break;
+            }
+            case "boolean": {
+                if (typeof val === "string") {
+                    val.toLowerCase() === "true" ? (val = true) : (val = false);
+                } else {
+                    val = !!val;
+                }
+                break;
+            }
+            case "datetime":
+            case "date": {
+                val = date_parser.parse(val);
+                break;
+            }
+            default: {
+                val += ""; // TODO this is not right - might not be a string.  Need a data cleaner
+            }
+        }
+
+        return val;
+    }
+
+    /**
+     * Resets the internal state of the accessor, preventing
+     * collisions with previously set data.
+     *
+     * @private
+     */
+    clean() {
+        this.date_parsers = {};
+        this.names = undefined;
+        this.types = undefined;
+    }
+
+    /**
+     * Links the accessor to a package of data for processing,
+     * calculating its format and size.
+     *
+     * @private
+     * @param {object} __MODULE__: the Module object generated by Emscripten
+     * @param {object} data
+     *
+     * @returns An object with 5 properties:
+     *    cdata - an array of columnar data.
+     *    names - the column names.
+     *    types - the column t_dtypes.
+     *    row_count - the number of rows per column.
+     *    is_arrow - an internal flag marking arrow-formatted data
+     */
+    init(__MODULE__, data) {
+        this.data = data;
+        this.format = this.is_format(this.data);
+        this.row_count = this.get_row_count(this.data);
+    }
+}
+
+/**
+ * Coerce string null into value null.
+ * @private
+ * @param {*} value
+ */
+export function clean_data(value) {
+    if (value === null || value === "null") {
+        return null;
+    } else if (value === undefined || value === "undefined") {
+        return undefined;
+    } else {
+        return value;
+    }
+}
diff --git a/packages/perspective/src/js/date_parser.js → ...pective/src/js/DataAccessor/DateParser.js b/packages/perspective/src/js/date_parser.js → ...pective/src/js/DataAccessor/DateParser.js
diff --git a/packages/perspective/src/js/parse_data.js b/packages/perspective/src/js/parse_data.js