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authorAndy Hayden <andyhayden1@gmail.com>2021-04-30 12:51:48 -0700
committerGitHub <noreply@github.com>2021-04-30 15:51:48 -0400
commit684c357136fd44f9d5a1b8bb4402400ed1354677 (patch)
treeebc14b1d01b6643dd4d588516692dffc0f8fcb52 /extensions/file/02_filereader.js
parentabaec7a88e991188d885bede652f35d76ab4f340 (diff)
Rename crate_ops to extensions (#10431)
Diffstat (limited to 'extensions/file/02_filereader.js')
-rw-r--r--extensions/file/02_filereader.js414
1 files changed, 414 insertions, 0 deletions
diff --git a/extensions/file/02_filereader.js b/extensions/file/02_filereader.js
new file mode 100644
index 000000000..9575ab85a
--- /dev/null
+++ b/extensions/file/02_filereader.js
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+// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+
+// @ts-check
+/// <reference no-default-lib="true" />
+/// <reference path="../../core/lib.deno_core.d.ts" />
+/// <reference path="../webidl/internal.d.ts" />
+/// <reference path="../web/internal.d.ts" />
+/// <reference path="../web/lib.deno_web.d.ts" />
+/// <reference path="./internal.d.ts" />
+/// <reference path="./lib.deno_file.d.ts" />
+/// <reference lib="esnext" />
+
+"use strict";
+
+((window) => {
+ const webidl = window.__bootstrap.webidl;
+ const { decode } = window.__bootstrap.encoding;
+ const { parseMimeType } = window.__bootstrap.mimesniff;
+ const base64 = window.__bootstrap.base64;
+
+ const state = Symbol("[[state]]");
+ const result = Symbol("[[result]]");
+ const error = Symbol("[[error]]");
+ const aborted = Symbol("[[aborted]]");
+
+ class FileReader extends EventTarget {
+ get [Symbol.toStringTag]() {
+ return "FileReader";
+ }
+
+ /** @type {"empty" | "loading" | "done"} */
+ [state] = "empty";
+ /** @type {null | string | ArrayBuffer} */
+ [result] = null;
+ /** @type {null | DOMException} */
+ [error] = null;
+
+ [aborted] = false;
+
+ /**
+ * @param {Blob} blob
+ * @param {{kind: "ArrayBuffer" | "Text" | "DataUrl" | "BinaryString", encoding?: string}} readtype
+ */
+ #readOperation = (blob, readtype) => {
+ // 1. If fr’s state is "loading", throw an InvalidStateError DOMException.
+ if (this[state] === "loading") {
+ throw new DOMException(
+ "Invalid FileReader state.",
+ "InvalidStateError",
+ );
+ }
+ // 2. Set fr’s state to "loading".
+ this[state] = "loading";
+ // 3. Set fr’s result to null.
+ this[result] = null;
+ // 4. Set fr’s error to null.
+ this[error] = null;
+
+ // 5. Let stream be the result of calling get stream on blob.
+ const stream /*: ReadableStream<ArrayBufferView>*/ = blob.stream();
+
+ // 6. Let reader be the result of getting a reader from stream.
+ const reader = stream.getReader();
+
+ // 7. Let bytes be an empty byte sequence.
+ /** @type {Uint8Array[]} */
+ const chunks = [];
+
+ // 8. Let chunkPromise be the result of reading a chunk from stream with reader.
+ let chunkPromise = reader.read();
+
+ // 9. Let isFirstChunk be true.
+ let isFirstChunk = true;
+
+ // 10 in parallel while true
+ (async () => {
+ while (!this[aborted]) {
+ // 1. Wait for chunkPromise to be fulfilled or rejected.
+ try {
+ const chunk = await chunkPromise;
+ if (this[aborted]) return;
+
+ // 2. If chunkPromise is fulfilled, and isFirstChunk is true, queue a task to fire a progress event called loadstart at fr.
+ if (isFirstChunk) {
+ // TODO(lucacasonato): this is wrong, should be HTML "queue a task"
+ queueMicrotask(() => {
+ if (this[aborted]) return;
+ // fire a progress event for loadstart
+ const ev = new ProgressEvent("loadstart", {});
+ this.dispatchEvent(ev);
+ });
+ }
+ // 3. Set isFirstChunk to false.
+ isFirstChunk = false;
+
+ // 4. If chunkPromise is fulfilled with an object whose done property is false
+ // and whose value property is a Uint8Array object, run these steps:
+ if (!chunk.done && chunk.value instanceof Uint8Array) {
+ chunks.push(chunk.value);
+
+ // TODO(bartlomieju): (only) If roughly 50ms have passed since last progress
+ {
+ const size = chunks.reduce((p, i) => p + i.byteLength, 0);
+ const ev = new ProgressEvent("progress", {
+ loaded: size,
+ });
+ // TODO(lucacasonato): this is wrong, should be HTML "queue a task"
+ queueMicrotask(() => {
+ if (this[aborted]) return;
+ this.dispatchEvent(ev);
+ });
+ }
+
+ chunkPromise = reader.read();
+ } // 5 Otherwise, if chunkPromise is fulfilled with an object whose done property is true, queue a task to run the following steps and abort this algorithm:
+ else if (chunk.done === true) {
+ // TODO(lucacasonato): this is wrong, should be HTML "queue a task"
+ queueMicrotask(() => {
+ if (this[aborted]) return;
+ // 1. Set fr’s state to "done".
+ this[state] = "done";
+ // 2. Let result be the result of package data given bytes, type, blob’s type, and encodingName.
+ const size = chunks.reduce((p, i) => p + i.byteLength, 0);
+ const bytes = new Uint8Array(size);
+ let offs = 0;
+ for (const chunk of chunks) {
+ bytes.set(chunk, offs);
+ offs += chunk.byteLength;
+ }
+ switch (readtype.kind) {
+ case "ArrayBuffer": {
+ this[result] = bytes.buffer;
+ break;
+ }
+ case "BinaryString":
+ this[result] = [...new Uint8Array(bytes.buffer)].map((v) =>
+ String.fromCodePoint(v)
+ ).join("");
+ break;
+ case "Text": {
+ let decoder = undefined;
+ if (readtype.encoding) {
+ try {
+ decoder = new TextDecoder(readtype.encoding);
+ } catch {
+ // don't care about the error
+ }
+ }
+ if (decoder === undefined) {
+ const mimeType = parseMimeType(blob.type);
+ if (mimeType) {
+ const charset = mimeType.parameters.get("charset");
+ if (charset) {
+ try {
+ decoder = new TextDecoder(charset);
+ } catch {
+ // don't care about the error
+ }
+ }
+ }
+ }
+ if (decoder === undefined) {
+ decoder = new TextDecoder();
+ }
+ this[result] = decode(bytes, decoder.encoding);
+ break;
+ }
+ case "DataUrl": {
+ const mediaType = blob.type || "application/octet-stream";
+ this[result] = `data:${mediaType};base64,${
+ base64.fromByteArray(bytes)
+ }`;
+ break;
+ }
+ }
+ // 4.2 Fire a progress event called load at the fr.
+ {
+ const ev = new ProgressEvent("load", {
+ lengthComputable: true,
+ loaded: size,
+ total: size,
+ });
+ this.dispatchEvent(ev);
+ }
+
+ // 5. If fr’s state is not "loading", fire a progress event called loadend at the fr.
+ //Note: Event handler for the load or error events could have started another load, if that happens the loadend event for this load is not fired.
+ if (this[state] !== "loading") {
+ const ev = new ProgressEvent("loadend", {
+ lengthComputable: true,
+ loaded: size,
+ total: size,
+ });
+ this.dispatchEvent(ev);
+ }
+ });
+ break;
+ }
+ } catch (err) {
+ // TODO(lucacasonato): this is wrong, should be HTML "queue a task"
+ queueMicrotask(() => {
+ if (this[aborted]) return;
+
+ // chunkPromise rejected
+ this[state] = "done";
+ this[error] = err;
+
+ {
+ const ev = new ProgressEvent("error", {});
+ this.dispatchEvent(ev);
+ }
+
+ //If fr’s state is not "loading", fire a progress event called loadend at fr.
+ //Note: Event handler for the error event could have started another load, if that happens the loadend event for this load is not fired.
+ if (this[state] !== "loading") {
+ const ev = new ProgressEvent("loadend", {});
+ this.dispatchEvent(ev);
+ }
+ });
+ break;
+ }
+ }
+ })();
+ };
+
+ constructor() {
+ super();
+ this[webidl.brand] = webidl.brand;
+ }
+
+ /** @returns {number} */
+ get readyState() {
+ webidl.assertBranded(this, FileReader);
+ switch (this[state]) {
+ case "empty":
+ return FileReader.EMPTY;
+ case "loading":
+ return FileReader.LOADING;
+ case "done":
+ return FileReader.DONE;
+ default:
+ throw new TypeError("Invalid state");
+ }
+ }
+
+ get result() {
+ webidl.assertBranded(this, FileReader);
+ return this[result];
+ }
+
+ get error() {
+ webidl.assertBranded(this, FileReader);
+ return this[error];
+ }
+
+ abort() {
+ webidl.assertBranded(this, FileReader);
+ // If context object's state is "empty" or if context object's state is "done" set context object's result to null and terminate this algorithm.
+ if (
+ this[state] === "empty" ||
+ this[state] === "done"
+ ) {
+ this[result] = null;
+ return;
+ }
+ // If context object's state is "loading" set context object's state to "done" and set context object's result to null.
+ if (this[state] === "loading") {
+ this[state] = "done";
+ this[result] = null;
+ }
+ // If there are any tasks from the context object on the file reading task source in an affiliated task queue, then remove those tasks from that task queue.
+ // Terminate the algorithm for the read method being processed.
+ this[aborted] = true;
+
+ // Fire a progress event called abort at the context object.
+ const ev = new ProgressEvent("abort", {});
+ this.dispatchEvent(ev);
+
+ // If context object's state is not "loading", fire a progress event called loadend at the context object.
+ if (this[state] !== "loading") {
+ const ev = new ProgressEvent("loadend", {});
+ this.dispatchEvent(ev);
+ }
+ }
+
+ /** @param {Blob} blob */
+ readAsArrayBuffer(blob) {
+ webidl.assertBranded(this, FileReader);
+ const prefix = "Failed to execute 'readAsArrayBuffer' on 'FileReader'";
+ webidl.requiredArguments(arguments.length, 1, { prefix });
+ this.#readOperation(blob, { kind: "ArrayBuffer" });
+ }
+
+ /** @param {Blob} blob */
+ readAsBinaryString(blob) {
+ webidl.assertBranded(this, FileReader);
+ const prefix = "Failed to execute 'readAsBinaryString' on 'FileReader'";
+ webidl.requiredArguments(arguments.length, 1, { prefix });
+ // alias for readAsArrayBuffer
+ this.#readOperation(blob, { kind: "BinaryString" });
+ }
+
+ /** @param {Blob} blob */
+ readAsDataURL(blob) {
+ webidl.assertBranded(this, FileReader);
+ const prefix = "Failed to execute 'readAsBinaryString' on 'FileReader'";
+ webidl.requiredArguments(arguments.length, 1, { prefix });
+ // alias for readAsArrayBuffer
+ this.#readOperation(blob, { kind: "DataUrl" });
+ }
+
+ /**
+ * @param {Blob} blob
+ * @param {string} [encoding]
+ */
+ readAsText(blob, encoding) {
+ webidl.assertBranded(this, FileReader);
+ const prefix = "Failed to execute 'readAsBinaryString' on 'FileReader'";
+ webidl.requiredArguments(arguments.length, 1, { prefix });
+ if (encoding !== undefined) {
+ encoding = webidl.converters["DOMString"](encoding, {
+ prefix,
+ context: "Argument 2",
+ });
+ }
+ // alias for readAsArrayBuffer
+ this.#readOperation(blob, { kind: "Text", encoding });
+ }
+ }
+
+ Object.defineProperty(FileReader, "EMPTY", {
+ writable: false,
+ enumerable: true,
+ configurable: false,
+ value: 0,
+ });
+ Object.defineProperty(FileReader, "LOADING", {
+ writable: false,
+ enumerable: true,
+ configurable: false,
+ value: 1,
+ });
+ Object.defineProperty(FileReader, "DONE", {
+ writable: false,
+ enumerable: true,
+ configurable: false,
+ value: 2,
+ });
+ Object.defineProperty(FileReader.prototype, "EMPTY", {
+ writable: false,
+ enumerable: true,
+ configurable: false,
+ value: 0,
+ });
+ Object.defineProperty(FileReader.prototype, "LOADING", {
+ writable: false,
+ enumerable: true,
+ configurable: false,
+ value: 1,
+ });
+ Object.defineProperty(FileReader.prototype, "DONE", {
+ writable: false,
+ enumerable: true,
+ configurable: false,
+ value: 2,
+ });
+
+ const handlerSymbol = Symbol("eventHandlers");
+
+ function makeWrappedHandler(handler) {
+ function wrappedHandler(...args) {
+ if (typeof wrappedHandler.handler !== "function") {
+ return;
+ }
+ return wrappedHandler.handler.call(this, ...args);
+ }
+ wrappedHandler.handler = handler;
+ return wrappedHandler;
+ }
+ // TODO(benjamingr) reuse when we can reuse code between web crates
+ function defineEventHandler(emitter, name) {
+ // HTML specification section 8.1.5.1
+ Object.defineProperty(emitter, `on${name}`, {
+ get() {
+ return this[handlerSymbol]?.get(name)?.handler ?? null;
+ },
+ set(value) {
+ if (!this[handlerSymbol]) {
+ this[handlerSymbol] = new Map();
+ }
+ let handlerWrapper = this[handlerSymbol]?.get(name);
+ if (handlerWrapper) {
+ handlerWrapper.handler = value;
+ } else {
+ handlerWrapper = makeWrappedHandler(value);
+ this.addEventListener(name, handlerWrapper);
+ }
+ this[handlerSymbol].set(name, handlerWrapper);
+ },
+ configurable: true,
+ enumerable: true,
+ });
+ }
+ defineEventHandler(FileReader.prototype, "error");
+ defineEventHandler(FileReader.prototype, "loadstart");
+ defineEventHandler(FileReader.prototype, "load");
+ defineEventHandler(FileReader.prototype, "loadend");
+ defineEventHandler(FileReader.prototype, "progress");
+ defineEventHandler(FileReader.prototype, "abort");
+
+ window.__bootstrap.fileReader = {
+ FileReader,
+ };
+})(this);