feat(ext/web): add CompressionStream API (#11728)

Co-authored-by: Luca Casonato <hello@lcas.dev>
Co-authored-by: Ryan Dahl <ry@tinyclouds.org>

ext/web/14_compression.js

@@ -0,0 +1,123 @@
+// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
+
+// @ts-check
+/// <reference path="../../core/lib.deno_core.d.ts" />
+/// <reference path="./internal.d.ts" />
+/// <reference path="./lib.deno_web.d.ts" />
+
+"use strict";
+
+((window) => {
+  const core = window.Deno.core;
+  const webidl = window.__bootstrap.webidl;
+  const { TransformStream } = window.__bootstrap.streams;
+
+  webidl.converters.CompressionFormat = webidl.createEnumConverter(
+    "CompressionFormat",
+    [
+      "deflate",
+      "gzip",
+    ],
+  );
+
+  class CompressionStream {
+    #transform;
+
+    constructor(format) {
+      const prefix = "Failed to construct 'CompressionStream'";
+      webidl.requiredArguments(arguments.length, 1, { prefix });
+      format = webidl.converters.CompressionFormat(format, {
+        prefix,
+        context: "Argument 1",
+      });
+
+      const rid = core.opSync("op_compression_new", format, false);
+
+      this.#transform = new TransformStream({
+        transform(chunk, controller) {
+          // TODO(lucacasonato): convert chunk to BufferSource
+          const output = core.opSync(
+            "op_compression_write",
+            rid,
+            chunk,
+          );
+          maybeEnqueue(controller, output);
+        },
+        flush(controller) {
+          const output = core.opSync("op_compression_finish", rid);
+          maybeEnqueue(controller, output);
+        },
+      });
+
+      this[webidl.brand] = webidl.brand;
+    }
+
+    get readable() {
+      webidl.assertBranded(this, CompressionStream);
+      return this.#transform.readable;
+    }
+
+    get writable() {
+      webidl.assertBranded(this, CompressionStream);
+      return this.#transform.writable;
+    }
+  }
+
+  webidl.configurePrototype(CompressionStream);
+
+  class DecompressionStream {
+    #transform;
+
+    constructor(format) {
+      const prefix = "Failed to construct 'DecompressionStream'";
+      webidl.requiredArguments(arguments.length, 1, { prefix });
+      format = webidl.converters.CompressionFormat(format, {
+        prefix,
+        context: "Argument 1",
+      });
+
+      const rid = core.opSync("op_compression_new", format, true);
+
+      this.#transform = new TransformStream({
+        transform(chunk, controller) {
+          // TODO(lucacasonato): convert chunk to BufferSource
+          const output = core.opSync(
+            "op_compression_write",
+            rid,
+            chunk,
+          );
+          maybeEnqueue(controller, output);
+        },
+        flush(controller) {
+          const output = core.opSync("op_compression_finish", rid);
+          maybeEnqueue(controller, output);
+        },
+      });
+
+      this[webidl.brand] = webidl.brand;
+    }
+
+    get readable() {
+      webidl.assertBranded(this, DecompressionStream);
+      return this.#transform.readable;
+    }
+
+    get writable() {
+      webidl.assertBranded(this, DecompressionStream);
+      return this.#transform.writable;
+    }
+  }
+
+  function maybeEnqueue(controller, output) {
+    if (output && output.byteLength > 0) {
+      controller.enqueue(output);
+    }
+  }
+
+  webidl.configurePrototype(DecompressionStream);
+
+  window.__bootstrap.compression = {
+    CompressionStream,
+    DecompressionStream,
+  };
+})(globalThis);