add linux audio screensharing (#130)

Co-authored-by: V <vendicated@riseup.net>
Co-authored-by: kaitlynkitty <87152313+kaitlynkittyy@users.noreply.github.com>
Co-authored-by: Curve <fynnbwdt@gmail.com>

src/main/virtmic.ts

@@ -0,0 +1,66 @@
+/*
+ * SPDX-License-Identifier: GPL-3.0
+ * Vesktop, a desktop app aiming to give you a snappier Discord Experience
+ * Copyright (c) 2023 Vendicated and Vencord contributors
+ */
+
+import { app, ipcMain } from "electron";
+import { join } from "path";
+import { IpcEvents } from "shared/IpcEvents";
+import { STATIC_DIR } from "shared/paths";
+
+let initialized = false;
+let patchBay: import("@vencord/venmic").PatchBay | undefined;
+
+function getRendererAudioServicePid() {
+    return (
+        app
+            .getAppMetrics()
+            .find(proc => proc.name === "Audio Service")
+            ?.pid?.toString() ?? "owo"
+    );
+}
+
+function obtainVenmic() {
+    if (!initialized) {
+        initialized = true;
+        try {
+            const { PatchBay } = require(join(STATIC_DIR, "dist/venmic.node")) as typeof import("@vencord/venmic");
+            patchBay = new PatchBay();
+        } catch (e) {
+            console.error("Failed to initialise venmic. Make sure you're using pipewire", e);
+        }
+    }
+
+    return patchBay;
+}
+
+ipcMain.handle(IpcEvents.VIRT_MIC_LIST, () => {
+    const audioPid = getRendererAudioServicePid();
+    return obtainVenmic()
+        ?.list()
+        .filter(s => s["application.process.id"] !== audioPid)
+        .map(s => s["application.name"]);
+});
+
+ipcMain.handle(
+    IpcEvents.VIRT_MIC_START,
+    (_, target: string) =>
+        obtainVenmic()?.link({
+            key: "application.name",
+            value: target,
+            mode: "include"
+        })
+);
+
+ipcMain.handle(
+    IpcEvents.VIRT_MIC_START_SYSTEM,
+    () =>
+        obtainVenmic()?.link({
+            key: "application.process.id",
+            value: getRendererAudioServicePid(),
+            mode: "exclude"
+        })
+);
+
+ipcMain.handle(IpcEvents.VIRT_MIC_STOP, () => obtainVenmic()?.unlink());