Some terribleness to make updating work on windows

Squirrel doesn't handle the executable changing name, as hopefully
explained in comments

build/rebrand_stub/rebrand_stub.c

@@ -0,0 +1,51 @@
+#include <windows.h>
+#include <stdio.h>
+#include <string.h>
+#include <tchar.h>
+
+/*
+ * This just runs 'Element (Riot).exe' with the same args as
+ * this process was invoked with. This gets around the fact that
+ * squirrel always tries to run an executable with the same name,
+ * so fails to restart if the app's name has changed.
+ */
+void _tmain( int argc, TCHAR *argv[] )
+{
+    LPSTR myCmdLine = GetCommandLineA();
+    char cmdLine[32767];
+
+    LPSTR cmdLinePos = cmdLine;
+    LPSTR toRun = "\"Element (Riot).exe\" ";
+    strncpy(cmdLinePos, toRun, strlen(toRun));
+    cmdLinePos += strlen(toRun);
+
+    if (myCmdLine[0] == '"') ++myCmdLine;
+    myCmdLine += strlen(argv[0]);
+    if (myCmdLine[0] == '"') ++myCmdLine;
+    if (myCmdLine[0] == ' ') ++myCmdLine;
+
+    strncpy(cmdLinePos, myCmdLine, (cmdLine + 32767) - cmdLinePos);
+
+    STARTUPINFO si;
+    PROCESS_INFORMATION pi;
+
+    ZeroMemory(&si, sizeof(si));
+    si.cb = sizeof(si);
+    ZeroMemory(&pi, sizeof(pi));
+
+    if (!CreateProcess(NULL,
+        cmdLine,        // Command line
+        NULL,           // Process handle not inheritable
+        NULL,           // Thread handle not inheritable
+        FALSE,          // Set handle inheritance to FALSE
+        0,              // No creation flags
+        NULL,           // Use parent's environment block
+        NULL,           // Use parent's starting directory 
+        &si,            // Pointer to STARTUPINFO structure
+        &pi )           // Pointer to PROCESS_INFORMATION structure
+    ) 
+    {
+        printf("CreateProcess failed (%d).\n", GetLastError());
+        return;
+    }
+}

package.json

@@ -4,7 +4,7 @@
   "main": "src/electron-main.js",
   "version": "1.6.6",
   "description": "A feature-rich client for Matrix.org",
-  "author": "Element Communications Ltd.",
+  "author": "Element",
   "repository": {
     "type": "git",
     "url": "https://github.com/vector-im/riot-desktop"
@@ -100,6 +100,7 @@
     "directories": {
       "output": "dist"
     },
+    "afterPack": "scripts/electron_afterPack",
     "afterSign": "scripts/electron_afterSign",
     "protocols": [
       {

scripts/electron_afterPack.js

@@ -0,0 +1,15 @@
+const fsProm = require('fs').promises;
+const path = require('path');
+
+exports.default = async function(context) {
+    const { electronPlatformName, appOutDir } = context;
+
+    // Squirrel windows will try to relaunch the app using an executable of the same name as
+    // before in the new version, so will fail if the executable is now called something else.
+    // We add a fake Riot.exe that it can run which runs the real one.
+    // This also gets signed automatically, presumably because electron-build just looks for all
+    // exe files and signs them all...
+    if (electronPlatformName === 'win32') {
+        await fsProm.copyFile('build/rebrand_stub/rebrand_stub.exe', path.join(appOutDir, "Riot.exe"));
+    }
+};

src/squirrelhooks.js

@@ -17,17 +17,20 @@ limitations under the License.
 const path = require('path');
 const spawn = require('child_process').spawn;
 const {app} = require('electron');
+const fsProm = require('fs').promises;
 
-function runUpdateExe(args, done) {
+function runUpdateExe(args) {
     // Invokes Squirrel's Update.exe which will do things for us like create shortcuts
     // Note that there's an Update.exe in the app-x.x.x directory and one in the parent
     // directory: we need to run the one in the parent directory, because it discovers
     // information about the app by inspecting the directory it's run from.
     const updateExe = path.resolve(path.dirname(process.execPath), '..', 'Update.exe');
     console.log(`Spawning '${updateExe}' with args '${args}'`);
-    spawn(updateExe, args, {
-      detached: true,
-    }).on('close', done);
+    return new Promise(resolve => {
+        spawn(updateExe, args, {
+          detached: true,
+        }).on('close', resolve);
+    });
 }
 
 function checkSquirrelHooks() {
@@ -36,10 +39,29 @@ function checkSquirrelHooks() {
     const cmd = process.argv[1];
     const target = path.basename(process.execPath);
     if (cmd === '--squirrel-install' || cmd === '--squirrel-updated') {
-        runUpdateExe(['--createShortcut=' + target + ''], app.quit);
+        Promise.resolve().then(() => {
+            return runUpdateExe(['--createShortcut=' + target]);
+        }).then(() => {
+            // remove the old 'Riot' shortcuts, if they exist (update.exe --removeShortcut doesn't work
+            // because it always uses the name of the product as the name of the shortcut: the only variable
+            // is what executable you're linking to)
+            const appDataDir = process.env.APPDATA;
+            if (!appDataDir) return;
+            const startMenuDir = path.join(
+                appDataDir, 'Microsoft', 'Windows', 'Start Menu', 'Programs', 'New Vector Ltd',
+            );
+            return fsProm.rmdir(startMenuDir, { recursive: true });
+        }).then(() => {
+            const oldDesktopShortcut = path.join(app.getPath('desktop'), 'Riot.lnk');
+            return fsProm.unlink(oldDesktopShortcut).catch(() => {});
+        }).then(() => {
+            app.quit();
+        });
         return true;
     } else if (cmd === '--squirrel-uninstall') {
-        runUpdateExe(['--removeShortcut=' + target + ''], app.quit);
+        runUpdateExe(['--removeShortcut=' + target]).then(() => {
+            app.quit();
+        });
         return true;
     } else if (cmd === '--squirrel-obsolete') {
         app.quit();