mirror of
https://github.com/denoland/deno.git
synced 2024-11-01 09:24:20 -04:00
260 lines
8.7 KiB
JavaScript
260 lines
8.7 KiB
JavaScript
// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
|
||
|
||
((window) => {
|
||
const base64 = window.__bootstrap.base64;
|
||
|
||
async function readOperation(fr, blob, readtype) {
|
||
// Implementation from https://w3c.github.io/FileAPI/ notes
|
||
// And body of deno blob.ts readBytes
|
||
|
||
fr.aborting = false;
|
||
|
||
// 1. If fr’s state is "loading", throw an InvalidStateError DOMException.
|
||
if (fr.readyState === FileReader.LOADING) {
|
||
throw new DOMException(
|
||
"Invalid FileReader state.",
|
||
"InvalidStateError",
|
||
);
|
||
}
|
||
// 2. Set fr’s state to "loading".
|
||
fr.readyState = FileReader.LOADING;
|
||
// 3. Set fr’s result to null.
|
||
fr.result = null;
|
||
// 4. Set fr’s error to null.
|
||
fr.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.
|
||
//let bytes = new Uint8Array();
|
||
const chunks /*: Uint8Array[]*/ = [];
|
||
|
||
// 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
|
||
while (!fr.aborting) {
|
||
// 1. Wait for chunkPromise to be fulfilled or rejected.
|
||
try {
|
||
const chunk = await chunkPromise;
|
||
|
||
// 2. If chunkPromise is fulfilled, and isFirstChunk is true, queue a task to fire a progress event called loadstart at fr.
|
||
if (isFirstChunk) {
|
||
queueMicrotask(() => {
|
||
// fire a progress event for loadstart
|
||
const ev = new ProgressEvent("loadstart", {});
|
||
fr.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: (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,
|
||
});
|
||
fr.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) {
|
||
queueMicrotask(() => {
|
||
if (fr.aborting) {
|
||
return;
|
||
}
|
||
|
||
// 1. Set fr’s state to "done".
|
||
fr.readyState = FileReader.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": {
|
||
fr.result = bytes.buffer;
|
||
break;
|
||
}
|
||
case "Text": {
|
||
const decoder = new TextDecoder(readtype.encoding);
|
||
fr.result = decoder.decode(bytes.buffer);
|
||
break;
|
||
}
|
||
case "DataUrl": {
|
||
fr.result = "data:application/octet-stream;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,
|
||
});
|
||
fr.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 (fr.readyState !== FileReader.LOADING) {
|
||
const ev = new ProgressEvent("loadend", {
|
||
lengthComputable: true,
|
||
loaded: size,
|
||
total: size,
|
||
});
|
||
fr.dispatchEvent(ev);
|
||
}
|
||
});
|
||
|
||
break;
|
||
}
|
||
} catch (err) {
|
||
if (fr.aborting) {
|
||
break;
|
||
}
|
||
|
||
// chunkPromise rejected
|
||
fr.readyState = FileReader.DONE;
|
||
fr.error = err;
|
||
|
||
{
|
||
const ev = new ProgressEvent("error", {});
|
||
fr.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 (fr.readyState !== FileReader.LOADING) {
|
||
const ev = new ProgressEvent("loadend", {});
|
||
fr.dispatchEvent(ev);
|
||
}
|
||
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
class FileReader extends EventTarget {
|
||
error = null;
|
||
readyState = FileReader.EMPTY;
|
||
result = null;
|
||
aborting = false;
|
||
|
||
constructor() {
|
||
super();
|
||
}
|
||
|
||
abort() {
|
||
// 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.readyState === FileReader.EMPTY ||
|
||
this.readyState === FileReader.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.readyState === FileReader.LOADING) {
|
||
this.readyState = FileReader.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.aborting = 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.readyState !== FileReader.LOADING) {
|
||
const ev = new ProgressEvent("loadend", {});
|
||
this.dispatchEvent(ev);
|
||
}
|
||
}
|
||
readAsArrayBuffer(blob) {
|
||
readOperation(this, blob, { kind: "ArrayBuffer" });
|
||
}
|
||
readAsBinaryString(blob) {
|
||
// alias for readAsArrayBuffer
|
||
readOperation(this, blob, { kind: "ArrayBuffer" });
|
||
}
|
||
readAsDataURL(blob) {
|
||
readOperation(this, blob, { kind: "DataUrl" });
|
||
}
|
||
readAsText(blob, encoding) {
|
||
readOperation(this, blob, { kind: "Text", encoding });
|
||
}
|
||
}
|
||
|
||
FileReader.EMPTY = 0;
|
||
FileReader.LOADING = 1;
|
||
FileReader.DONE = 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;
|
||
},
|
||
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);
|