main/core: changed code so that headless would run truly headless with QCoreApplication instead of QApplication

QApplication is designed for GUI/widget programs and thus fails to launch if no window system is available. For a true headless mode, we must swap out with QCoreApplication. However, what complicates this is that QCommandLineParser - the class we use to determine whether we should run in GUI mode or not - requires an active application instance to work. This creates an unfortunate catch-22 that ultimately ended in writing a custom command line parser. Now we can correctly swap out with QCoreApplication, however this has exposed other issues regarding functions that unnecessarily rely on QWidget functions. So they'll need to be sorted out eventually.
2020-08-22 00:22:19 +10:00
parent 9aabde303e
commit 48ac8ea509
6 changed files with 450 additions and 122 deletions
@@ -0,0 +1,149 @@
+/***
+
+  Olive - Non-Linear Video Editor
+  Copyright (C) 2019 Olive Team
+
+  This program is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+***/
+
+#include "commandlineparser.h"
+
+#include <QCoreApplication>
+#include <QDebug>
+
+CommandLineParser::~CommandLineParser()
+{
+  foreach (const KnownOption& o, options_) {
+    delete o.option;
+  }
+
+  foreach (const KnownPositionalArgument& a, positional_args_) {
+    delete a.option;
+  }
+}
+
+const CommandLineParser::Option *CommandLineParser::AddOption(const QStringList &strings, const QString &description)
+{
+  Option* o = new Option();
+
+  options_.append({strings, description, o});
+
+  return o;
+}
+
+const CommandLineParser::PositionalArgument *CommandLineParser::AddPositionalArgument(const QString &name, const QString &description, bool required)
+{
+  PositionalArgument* a = new PositionalArgument();
+
+  positional_args_.append({name, description, a, required});
+
+  return a;
+}
+
+void CommandLineParser::Process(int argc, char **argv)
+{
+  int positional_index = 0;
+
+  for (int i=1; i<argc; i++) {
+    if (argv[i][0] == '-') {
+      // Must be an option
+
+      // Skip past first dashes
+      const char* arg_basename = &argv[i][1];
+
+      bool matched_known = false;
+
+      for (int j=0; j<options_.size(); j++) {
+        KnownOption& o = options_[j];
+
+        foreach (const QString& s, o.args) {
+          if (!s.compare(arg_basename, Qt::CaseInsensitive)) {
+            // Flag discovered!
+            o.option->Set();
+            matched_known = true;
+            goto found_flag;
+          }
+        }
+      }
+
+found_flag:
+      if (!matched_known) {
+        qWarning() << "Unknown parameter:" << argv[i];
+      }
+
+    } else {
+      // Must be a positional flag
+      if (positional_index < positional_args_.size()) {
+        positional_args_[positional_index].option->SetSetting(argv[i]);
+        positional_index++;
+      } else {
+        qWarning() << "Unknown parameter:" << argv[i];
+      }
+    }
+  }
+}
+
+void CommandLineParser::PrintHelp(const char* filename)
+{
+  printf("%s %s\n",
+         QCoreApplication::applicationName().toUtf8().constData(),
+         QCoreApplication::applicationVersion().toUtf8().constData());
+
+  printf("Copyright (C) 2018-2020 Olive Team\n");
+
+  QString positional_args;
+  for (int i=0; i<positional_args_.size(); i++) {
+    if (i > 0) {
+      positional_args.append(' ');
+    }
+
+    positional_args.append('[');
+    positional_args.append(positional_args_.at(i).name);
+    positional_args.append(']');
+  }
+
+  const char* basename;
+#ifdef Q_OS_WINDOWS
+  basename = strrchr(filename, '\\');
+  if (!basename) {
+    basename = strrchr(filename, '/');
+  }
+#else
+  basename = strrchr(filename, '/');
+#endif
+
+  printf("Usage: %s [options] %s\n\n", basename + 1, positional_args.toUtf8().constData());
+
+  foreach (const KnownOption& o, options_) {
+    QString all_args;
+
+    for (int i=0; i<o.args.size(); i++) {
+      if (i > 0) {
+        all_args.append(QStringLiteral(", "));
+      }
+
+      const QString& this_arg = o.args.at(i);
+
+      all_args.append('-');
+      all_args.append(this_arg);
+    }
+
+    printf("    %s\n", all_args.toUtf8().constData());
+
+    printf("        %s\n\n", o.description.toUtf8().constData());
+  }
+
+  printf("\n");
+}