Add "--stdin-file-ext" option

This option allows to define the extension of the file generated by
reading the stdin when the "-" parameter is passed.

src/vs/code/node/cli.ts

@@ -160,7 +160,7 @@ export async function main(argv: string[]): Promise<any> {
 			// checking for stdin being connected to a TTY is not enough (https://github.com/microsoft/vscode/issues/40351)
 
 			if (hasReadStdinArg) {
-				stdinFilePath = getStdinFilePath();
+				stdinFilePath = getStdinFilePath(args['stdin-file-ext']);
 
 				// returns a file path where stdin input is written into (write in progress).
 				try {

src/vs/platform/environment/common/argv.ts

@@ -23,6 +23,7 @@ export interface NativeParsedArgs {
 	'new-window'?: boolean;
 	'unity-launch'?: boolean; // Always open a new window, except if opening the first window or opening a file or folder as part of the launch.
 	'reuse-window'?: boolean;
+	'stdin-file-ext'?: string;
 	locale?: string;
 	'user-data-dir'?: string;
 	'prof-startup'?: boolean;

src/vs/platform/environment/node/argv.ts

@@ -45,6 +45,7 @@ export const OPTIONS: OptionDescriptions<Required<NativeParsedArgs>> = {
 	'reuse-window': { type: 'boolean', cat: 'o', alias: 'r', description: localize('reuseWindow', "Force to open a file or folder in an already opened window.") },
 	'wait': { type: 'boolean', cat: 'o', alias: 'w', description: localize('wait', "Wait for the files to be closed before returning.") },
 	'waitMarkerFilePath': { type: 'string' },
+	'stdin-file-ext': { type: 'string', cat: 'o', description: localize('stdinFileExt', "The extension appended to the file generated by stdin reading.") },
 	'locale': { type: 'string', cat: 'o', args: 'locale', description: localize('locale', "The locale to use (e.g. en-US or zh-TW).") },
 	'user-data-dir': { type: 'string', cat: 'o', args: 'dir', description: localize('userDataDir', "Specifies the directory that user data is kept in. Can be used to open multiple distinct instances of Code.") },
 	'help': { type: 'boolean', cat: 'o', alias: 'h', description: localize('help', "Print usage.") },

src/vs/platform/environment/node/stdin.ts

@@ -35,8 +35,10 @@ export function stdinDataListener(durationinMs: number): Promise<boolean> {
 	});
 }
 
-export function getStdinFilePath(): string {
-	return paths.join(os.tmpdir(), `code-stdin-${Math.random().toString(36).replace(/[^a-z]+/g, '').substr(0, 3)}`);
+export function getStdinFilePath(ext?: string | undefined): string {
+	const suffix = ext ? `.${ext}` : '';
+	const rnd = Math.random().toString(36).replace(/[^a-z]+/g, '').substr(0, 3);
+	return paths.join(os.tmpdir(), `code-stdin-${rnd}${suffix}`);
 }
 
 export async function readFromStdin(targetPath: string, verbose: boolean): Promise<void> {