Protoype of a faster RPC protocol

Signed-off-by: Thomas Mäder <tmader@redhat.com>

packages/core/src/common/message-rpc/README.md

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+# message-rpc
+
+An attempt to rewrite the theia RPC infrastructure with a couple of changes:
+
+1. "Zero-copy" message writing and reading
+2. Support for binary buffers without ever encoding them
+3. Separate RPC server from RPC client
+4. Use a unified "Channel" interface
+
+A lot of this code is more or less copied from the current Theia code.

packages/core/src/common/message-rpc/array-buffer-message-buffer.spec.ts

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+/********************************************************************************
+ * Copyright (C) 2021 Red Hat, Inc. and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+import { expect } from 'chai';
+import { ArrayBufferReadBuffer, ArrrayBufferWriteBuffer } from './array-buffer-message-buffer';
+
+describe('array message buffer tests', () => {
+    it('basic read write test', () => {
+        const buffer = new ArrayBuffer(1024);
+        const writer = new ArrrayBufferWriteBuffer(buffer);
+
+        writer.writeByte(8);
+        writer.writeInt(10000);
+        writer.writeBytes(new Uint8Array([1, 2, 3, 4]));
+        writer.writeString('this is a string');
+        writer.writeString('another string');
+        writer.commit();
+
+        const written = writer.getCurrentContents();
+
+        const reader = new ArrayBufferReadBuffer(written);
+
+        expect(reader.readByte()).equal(8);
+        expect(reader.readInt()).equal(10000);
+        expect(reader.readBytes()).deep.equal(new Uint8Array([1, 2, 3, 4]).buffer);
+        expect(reader.readString()).equal('this is a string');
+        expect(reader.readString()).equal('another string');
+    });
+});

packages/core/src/common/message-rpc/array-buffer-message-buffer.ts

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+/********************************************************************************
+ * Copyright (C) 2021 Red Hat, Inc. and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+import { Emitter, Event } from '../event';
+import { ReadBuffer, WriteBuffer } from './message-buffer';
+
+export class ArrrayBufferWriteBuffer implements WriteBuffer {
+    constructor(private buffer: ArrayBuffer = new ArrayBuffer(1024), private offset: number = 0) {
+    }
+
+    private get msg(): DataView {
+        return new DataView(this.buffer);
+    }
+
+    ensureCapacity(value: number): WriteBuffer {
+        let newLength = this.buffer.byteLength;
+        while (newLength < this.offset + value) {
+            newLength *= 2;
+        }
+        if (newLength !== this.buffer.byteLength) {
+            const newBuffer = new ArrayBuffer(newLength);
+            new Uint8Array(newBuffer).set(new Uint8Array(this.buffer));
+            this.buffer = newBuffer;
+        }
+        return this;
+    }
+
+    writeByte(value: number): WriteBuffer {
+        this.ensureCapacity(1);
+        this.msg.setUint8(this.offset++, value);
+        return this;
+    }
+
+    writeInt(value: number): WriteBuffer {
+        this.ensureCapacity(4);
+        this.msg.setUint32(this.offset, value);
+        this.offset += 4;
+        return this;
+    }
+
+    writeString(value: string): WriteBuffer {
+        const encoded = this.encodeString(value);
+        this.writeBytes(encoded);
+        return this;
+    }
+
+    private encodeString(value: string): Uint8Array {
+        return new TextEncoder().encode(value);
+    }
+
+    writeBytes(value: ArrayBuffer): WriteBuffer {
+        this.ensureCapacity(value.byteLength + 4);
+        this.writeInt(value.byteLength);
+        new Uint8Array(this.buffer).set(new Uint8Array(value), this.offset);
+        this.offset += value.byteLength;
+        return this;
+    }
+
+    private onCommitEmitter = new Emitter<ArrayBuffer>();
+    get onCommit(): Event<ArrayBuffer> {
+        return this.onCommitEmitter.event;
+    }
+
+    commit(): void {
+        this.onCommitEmitter.fire(this.getCurrentContents());
+    }
+
+    getCurrentContents(): ArrayBuffer {
+        return this.buffer.slice(0, this.offset);
+    }
+}
+
+export class ArrayBufferReadBuffer implements ReadBuffer {
+    private offset: number = 0;
+
+    constructor(private readonly buffer: ArrayBuffer) {
+    }
+
+    private get msg(): DataView {
+        return new DataView(this.buffer);
+    }
+
+    readByte(): number {
+        return this.msg.getUint8(this.offset++);
+    }
+
+    readInt(): number {
+        const result = this.msg.getInt32(this.offset);
+        this.offset += 4;
+        return result;
+    }
+
+    readString(): string {
+        const len = this.msg.getUint32(this.offset);
+        this.offset += 4;
+        const result = this.decodeString(this.buffer.slice(this.offset, this.offset + len));
+        this.offset += len;
+        return result;
+    }
+
+    private decodeString(buf: ArrayBuffer): string {
+        return new TextDecoder().decode(buf);
+    }
+
+    readBytes(): ArrayBuffer {
+        const length = this.msg.getUint32(this.offset);
+        this.offset += 4;
+        const result = this.buffer.slice(this.offset, this.offset + length);
+        this.offset += length;
+        return result;
+    }
+}

packages/core/src/common/message-rpc/channel.spec.ts

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+/********************************************************************************
+ * Copyright (C) 2021 Red Hat, Inc. and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+import { assert, expect, spy, use } from 'chai';
+import * as spies from 'chai-spies';
+
+import { ChannelMultiplexer, ChannelPipe } from './channel';
+import { ReadBuffer } from './message-buffer';
+
+use(spies);
+
+describe('multiplexer test', () => {
+    it('multiplex message', async () => {
+        const pipe = new ChannelPipe();
+
+        const leftMultiplexer = new ChannelMultiplexer(pipe.left);
+        const rightMultiplexer = new ChannelMultiplexer(pipe.right);
+        const openChannelSpy = spy(() => {
+        });
+
+        rightMultiplexer.onDidOpenChannel(openChannelSpy);
+        leftMultiplexer.onDidOpenChannel(openChannelSpy);
+
+        const leftFirst = await leftMultiplexer.open('first');
+        const leftSecond = await leftMultiplexer.open('second');
+
+        const rightFirst = rightMultiplexer.getOpenChannel('first');
+        const rightSecond = rightMultiplexer.getOpenChannel('second');
+
+        assert.isNotNull(rightFirst);
+        assert.isNotNull(rightSecond);
+
+        const leftSecondSpy = spy((buf: ReadBuffer) => {
+            const message = buf.readString();
+            expect(message).equal('message for second');
+        });
+
+        leftSecond.onMessage(leftSecondSpy);
+
+        const rightFirstSpy = spy((buf: ReadBuffer) => {
+            const message = buf.readString();
+            expect(message).equal('message for first');
+        });
+
+        rightFirst!.onMessage(rightFirstSpy);
+
+        leftFirst.getWriteBuffer().writeString('message for first').commit();
+        rightSecond!.getWriteBuffer().writeString('message for second').commit();
+
+        expect(leftSecondSpy).to.be.called();
+        expect(rightFirstSpy).to.be.called();
+
+        expect(openChannelSpy).to.be.called.exactly(4);
+    })
+});