[beast: 59/70] EBEAST: parse command line, handle --version, --help and pass files to App

[Tim Janik <timj src gnome org>]

commit 2e2513849e2d39fb417f9218c6c4a2de6d2b9cd4
Author: Tim Janik <timj gnu org>
Date:   Wed Mar 8 15:27:34 2017 +0100

    EBEAST: parse command line, handle --version, --help and pass files to App
    
    Signed-off-by: Tim Janik <timj gnu org>

 ebeast/main.js |   89 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 87 insertions(+), 2 deletions(-)
---
diff --git a/ebeast/main.js b/ebeast/main.js
index a676544..2fa80ac 100644
--- a/ebeast/main.js
+++ b/ebeast/main.js
@@ -1,5 +1,89 @@
 // Licensed GNU LGPL v2.1 or later: http://www.gnu.org/licenses/lgpl.html
 const Electron = require ('electron');
+const ElectronDefaultApp = process.defaultApp !== undefined; // indicates unpackaged electron app
+const Eapp = Electron.app;
+
+// split command line options and return one at a time
+function pop_arg (args) {
+  if (!args.length)
+    return undefined;
+  let a = args.shift();
+  if (args.__nonoption__) {            // yield saved option argument
+    args.__nonoption__--;
+    return a;
+  }
+  if (args.skip_defaultapp) {          // finding defaultApp has precedence
+    if (/^[^-]/.test (a)) {
+      args.skip_defaultapp = false;    // consume process.defaultApp
+      return pop_arg (args);
+    }
+  }
+  if (args.seen_separator)             // yield only non-options after '--'
+    return a;
+  if (/^-[^-]+/.test (a)) {            // pop single letter option
+    const rest = a.slice (2);
+    if (/^=/.test (rest)) {            // save single letter option argument
+      args.unshift (rest.slice (1));
+      args.__nonoption__ = 1;
+    } else if (rest)
+      args.unshift ('-' + rest);       // save adjunct single letter options
+    return '-' + a[1];
+  } else if (/^--[^-]+/.test (a)) {    // pop long option
+    const eq = a.indexOf ('=');
+    if (eq > 0) {
+      args.unshift (a.slice (eq + 1)); // save long option argument
+      args.__nonoption__ = 1;
+      return a.slice (0, eq);
+    }
+    return a;
+  } else if (/^--$/.test (a)) {                // stop option parsing
+    args.seen_separator = true;
+    return pop_arg (args);
+  }
+  return a;
+}
+
+function print_help () {
+  const lines = [
+    `Usage: ${Eapp.getName()} [OPTIONS] [projectfiles...]`,
+    `Options:`,
+    `--help        Print command line option help`,
+    `--version     Print version information`,
+  ];
+  console.log (lines.join ('\n'));
+}
+
+// parse command line arguments
+const project_files = [];
+(function () {
+  let args = process.argv.slice (1);
+  args.skip_defaultapp = ElectronDefaultApp;
+  while (args.length) {
+    const arg = pop_arg (args);
+    if (args.seen_separator) {
+      project_files.push (arg);
+      continue;
+    }
+    switch (arg) {
+    case '--help':
+      print_help();
+      Eapp.exit (0);
+      break;
+    case '--version':
+      console.log (Eapp.getName() + ' ' + Eapp.getVersion());
+      Eapp.exit (0);
+      break;
+    default:
+      if (/^-/.test (arg)) {
+       console.log ('Unknown option: ' + arg);
+       print_help();
+       Eapp.exit (129);
+      }
+      project_files.push (arg);
+      break;
+    }
+  }
+}) ();
 
 // create the main ebeast window
 var win;
@@ -42,12 +126,13 @@ function create_window ()
     darkTheme: true,
   };
   win = new Electron.BrowserWindow (options);
+  win.bse_argv = project_files;
   win.once ('ready-to-show', () => { win.show(); });
   win.loadURL ('file:///' + __dirname + '/index.html');
   // win.webContents.openDevTools();
   win.on ('closed', () => { win = null; });
 }
-Electron.app.on ('ready', create_window); // create window once everything is loaded
+Eapp.on ('ready', create_window); // create window once everything is loaded
 
 // quit when all windows are closed.
-Electron.app.on ('window-all-closed', Electron.app.quit);
+Eapp.on ('window-all-closed', Eapp.quit);