From 1c5b44f9a132a7c93adac60a4c771c102d6c4aae Mon Sep 17 00:00:00 2001
From: Steven <steven@ceriously.com>
Date: Mon, 16 Aug 2021 16:51:23 -0400
Subject: [PATCH] Add loadFile parameter to ImagePool

---
 libsquoosh/README.md    | 15 +++++++--------
 libsquoosh/src/index.ts | 21 ++++++++++++---------
 2 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/libsquoosh/README.md b/libsquoosh/README.md
index cdb056501..80217af5e 100644
--- a/libsquoosh/README.md
+++ b/libsquoosh/README.md
@@ -16,7 +16,7 @@ You can start using the libSquoosh by adding these lines to the top of your JS p
 
 ```js
 import { ImagePool } from '@squoosh/lib';
-const imagePool = new ImagePool();
+const imagePool = new ImagePool((url) => fs.readFile(url));
 ```
 
 This will create an image pool with an underlying processing pipeline that you can use to ingest and encode images. The ImagePool constructor takes one argument that defines how many parallel operations it is allowed to run at any given time. By default, this number is set to the amount of CPU cores available in the system it is running on.
@@ -26,11 +26,11 @@ This will create an image pool with an underlying processing pipeline that you c
 You can ingest a new image like so:
 
 ```js
-const imagePath = 'path/to/image.png';
+const imagePath = 'file://path/to/image.png';
 const image = imagePool.ingestImage(imagePath);
 ```
 
-The `ingestImage` function can take anything the node [`readFile`][readfile] function can take, including a buffer and `FileHandle`.
+The `ingestImage` function will accept a URL path and call the `loadFile()` function defined in the `ImagePool`.
 
 The returned `image` object is a representation of the original image, that you can now preprocess, encode, and extract information about.
 
@@ -39,7 +39,7 @@ The returned `image` object is a representation of the original image, that you
 When an image has been ingested, you can start preprocessing it and encoding it to other formats. This example will resize the image and then encode it to a `.jpg` and `.jxl` image:
 
 ```js
-await image.decoded; //Wait until the image is decoded before running preprocessors. 
+await image.decoded; //Wait until the image is decoded before running preprocessors.
 
 const preprocessOptions = {
   //When both width and height are specified, the image resized to specified size.
@@ -47,7 +47,7 @@ const preprocessOptions = {
     enabled: true,
     width: 100,
     height: 50,
-  }
+  },
   /*
   //When either width or height is specified, the image resized to specified size keeping aspect ratio.
   resize: {
@@ -55,7 +55,7 @@ const preprocessOptions = {
     width: 100,
   }
   */
-}
+};
 await image.preprocess(preprocessOptions);
 
 const encodeOptions = {
@@ -63,9 +63,8 @@ const encodeOptions = {
   jxl: {
     quality: 90,
   },
-}
+};
 await image.encode(encodeOptions);
-
 ```
 
 The default values for each option can be found in the [`codecs.ts`][codecs.ts] file under `defaultEncoderOptions`. Every unspecified value will use the default value specified there. _Better documentation is needed here._
diff --git a/libsquoosh/src/index.ts b/libsquoosh/src/index.ts
index 48c150910..93041c2cd 100644
--- a/libsquoosh/src/index.ts
+++ b/libsquoosh/src/index.ts
@@ -1,5 +1,4 @@
 import { isMainThread } from 'worker_threads';
-import { cpus } from 'os';
 import { promises as fsp } from 'fs';
 
 import { codecs as encoders, preprocessors } from './codecs.js';
@@ -169,12 +168,12 @@ function handleJob(params: JobMessage) {
  * Represents an ingested image.
  */
 class Image {
-  public file: FileLike;
+  public file: ArrayBuffer;
   public workerPool: WorkerPool<JobMessage, any>;
   public decoded: Promise<{ bitmap: ImageData }>;
   public encodedWith: { [key: string]: any };
 
-  constructor(workerPool: WorkerPool<JobMessage, any>, file: FileLike) {
+  constructor(workerPool: WorkerPool<JobMessage, any>, file: ArrayBuffer) {
     this.file = file;
     this.workerPool = workerPool;
     this.decoded = workerPool.dispatchJob({ operation: 'decode', file });
@@ -251,22 +250,26 @@ class Image {
  */
 class ImagePool {
   public workerPool: WorkerPool<JobMessage, any>;
+  public loadFile: (path: URL) => Promise<ArrayBuffer>;
 
   /**
    * Create a new pool.
-   * @param {number} [threads] - Number of concurrent image processes to run in the pool. Defaults to the number of CPU cores in the system.
+   * @param {(path: URL) => Promise<ArrayBuffer>} [loadFile] - A function that loads a file from a URL.
+   * @param {number} [threads] - Number of concurrent image processes to run in the pool.
    */
-  constructor(threads: number) {
-    this.workerPool = new WorkerPool(threads || cpus().length, __filename);
+  constructor(loadFile: (path: URL) => Promise<ArrayBuffer>, threads: number) {
+    this.loadFile = loadFile;
+    this.workerPool = new WorkerPool(threads, __filename);
   }
 
   /**
    * Ingest an image into the image pool.
-   * @param {FileLike} image - The image or path to the image that should be ingested and decoded.
+   * @param {URL} url - The URL path to the image that should be ingested and decoded.
    * @returns {Image} - A custom class reference to the decoded image.
    */
-  ingestImage(image: FileLike): Image {
-    return new Image(this.workerPool, image);
+  ingestImage(url: URL): Image {
+    const file = await this.loadFile(url);
+    return new Image(this.workerPool, file);
   }
 
   /**