refactor plugin scan dialog into its own object

1 files changed, 208 insertions, 0 deletions

diff --git a/gtk2_ardour/plugin_scan_dialog.cc b/gtk2_ardour/plugin_scan_dialog.cc
new file mode 100644
index 0000000000..bddc5e5d91
--- /dev/null
+++ b/gtk2_ardour/plugin_scan_dialog.cc
@@ -0,0 +1,208 @@
+/*
+ * Copyright (C) 2005-2019 Paul Davis <paul@linuxaudiosystems.com>
+ * Copyright (C) 2012-2019 Robin Gareus <robin@gareus.org>
+ *
+ * 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 2 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, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifdef WAF_BUILD
+#include "gtk2ardour-config.h"
+#include "gtk2ardour-version.h"
+#endif
+
+#include <gtkmm/progressbar.h>
+
+#include "ardour/plugin_manager.h"
+
+#include "ardour_ui.h"
+#include "debug.h"
+#include "gui_thread.h"
+#include "plugin_scan_dialog.h"
+#include "ui_config.h"
+
+#include "pbd/i18n.h"
+
+using namespace ARDOUR;
+using namespace PBD;
+using namespace Gtk;
+using namespace std;
+
+PluginScanDialog::PluginScanDialog (bool just_cached, bool v)
+	: ArdourDialog (_("Scanning for plugins"))
+	, timeout_button (_("Stop Timeout"))
+	, cancel_button (_("Cancel Plugin Scan"))
+	, cache_only (just_cached)
+	, verbose (v)
+{
+	VBox* vbox = get_vbox();
+	vbox->set_size_request(400,-1);
+
+	message.set_padding (12, 12);
+	vbox->pack_start (message);
+
+	cancel_button.set_name ("EditorGTKButton");
+	cancel_button.signal_clicked().connect (sigc::mem_fun (*this, &PluginScanDialog::cancel_plugin_scan));
+	cancel_button.show();
+
+	vbox->pack_start (cancel_button, PACK_SHRINK);
+
+	timeout_button.set_name ("EditorGTKButton");
+	timeout_button.signal_clicked().connect (sigc::mem_fun (*this, &PluginScanDialog::cancel_plugin_timeout));
+	timeout_button.show();
+
+	pbar.set_orientation(Gtk::PROGRESS_RIGHT_TO_LEFT);
+	pbar.set_text(_("Scan Timeout"));
+	pbar.show();
+
+	tbox.pack_start (pbar, PACK_EXPAND_WIDGET, 4);
+	tbox.pack_start (timeout_button, PACK_SHRINK, 4);
+
+	vbox->pack_start (tbox, PACK_SHRINK, 4);
+
+	ARDOUR::PluginScanMessage.connect (connections, MISSING_INVALIDATOR, boost::bind(&PluginScanDialog::message_handler, this, _1, _2, _3), gui_context());
+	ARDOUR::PluginScanTimeout.connect (connections, MISSING_INVALIDATOR, boost::bind(&PluginScanDialog::plugin_scan_timeout, this, _1), gui_context());
+
+	vbox->show_all ();
+}
+
+void
+PluginScanDialog::start ()
+{
+	/* OK, this is extremely hard to understand on first reading, so please
+	 * read this and think about it carefully if you are confused.
+	 *
+	 * Plugin discovery must take place in the main thread of the
+	 * process. This is not true for all plugin APIs but it is true for VST
+	 * and AU. This means that the PluginManager::refresh() call MUST be
+	 * made from the main thread (typically the GUI thread, but certainly
+	 * the thread running main()). Failure to do this will cause crashes,
+	 * undefined behavior and other undesirable stuff (because plugin APIs
+	 * failed to specify this aspect of the host behavior).
+	 *
+	 * The ::refresh call is likely to be slow, particularly in the case of
+	 * VST(2) plugins where we are forced to load the shared object do
+	 * discovery (there is no separate metadata as with LV2 for
+	 * example). This means that it will block the GUI event loop where we
+	 * are calling it from. This is a problem.
+	 *
+	 * Normally we would solve this by running it in a separate thread, but
+	 * we cannot do this for reasons described above regarding plugin
+	 * discovery.
+	 *
+	 * We "solve" this by making the PluginManager emit a signal as it
+	 * examines every new plugin. Our handler for this signal checks the
+	 * message, and then runs ARDOUR_UI::gui_idle_handler() which flushes
+	 * the GUI event loop of pending events. This effectively handles
+	 * redraws and event input and all the usual stuff, meaning that the
+	 * GUI event loop appears to continue running during the ::refresh()
+	 * call. In reality, it only runs at the start of each plugin
+	 * discovery, so if the discovery process for a particular plugin takes
+	 * a long time (e.g. because it displays a licensing window and sits
+	 * waiting for input from the user), there's nothing we can do -
+	 * control will not be returned to our GUI event loop until that is
+	 * finished.
+	 *
+	 * This is a horrible design. Truly, really horrible. But it is caused
+	 * by plugin APIs failing to mandate that discovery can happen from any
+	 * thread and that plugins should NOT display a GUI or interact with
+	 * the user during discovery/instantiation. Fundamentally, all plugin
+	 * APIs should allow discovery without instantiation, like LV2 does
+	 * (and to a very limited extent like AU does, if you play some games
+	 * with the lower level APIs).
+	 *
+	 * For now (October 2019) it is the best we can come up with that does
+	 * not break when some VST plugin decides to behave stupidly.
+	 */
+
+
+	DEBUG_TRACE (DEBUG::GuiStartup, "plugin refresh starting\n");
+	PluginManager::instance().refresh (cache_only);
+	DEBUG_TRACE (DEBUG::GuiStartup, "plugin refresh complete\n");
+
+	/* scan is done at this point, return full control to main event loop */
+}
+
+void
+PluginScanDialog::cancel_plugin_scan ()
+{
+	PluginManager::instance().cancel_plugin_scan();
+}
+
+void
+PluginScanDialog::cancel_plugin_timeout ()
+{
+	PluginManager::instance().cancel_plugin_timeout();
+	timeout_button.set_sensitive (false);
+}
+
+void
+PluginScanDialog::plugin_scan_timeout (int timeout)
+{
+	if (!is_mapped()) {
+		return;
+	}
+
+	if (timeout > 0) {
+		pbar.set_sensitive (false);
+		timeout_button.set_sensitive (true);
+		pbar.set_fraction ((float) timeout / (float) Config->get_vst_scan_timeout());
+		tbox.show();
+	} else {
+		pbar.set_sensitive (false);
+		timeout_button.set_sensitive (false);
+	}
+
+	ARDOUR_UI::instance()->gui_idle_handler ();
+}
+
+void
+PluginScanDialog::message_handler (std::string type, std::string plugin, bool can_cancel)
+{
+	if (type == X_("closeme") && !is_mapped()) {
+		return;
+	}
+
+	const bool cancelled = PluginManager::instance().cancelled();
+
+	if (type != X_("closeme") && (!UIConfiguration::instance().get_show_plugin_scan_window()) && !verbose) {
+
+		if (cancelled && is_mapped()) {
+			hide();
+			connections.drop_connections();
+			ARDOUR_UI::instance()->gui_idle_handler ();
+			return;
+		}
+		if (cancelled || !can_cancel) {
+			return;
+		}
+	}
+
+	if (type == X_("closeme")) {
+		tbox.hide();
+		hide();
+		connections.drop_connections ();
+	} else {
+		message.set_text (type + ": " + Glib::path_get_basename(plugin));
+		show();
+	}
+
+	if (!can_cancel || !cancelled) {
+		timeout_button.set_sensitive(false);
+	}
+
+	cancel_button.set_sensitive(can_cancel && !cancelled);
+
+	ARDOUR_UI::instance()->gui_idle_handler ();
+}