[xpluginpath] Save/load plugin's path as relative to current session directory,

  when not found in any of the plugin search paths. (EXPERIMENTAL)

Author: rncbc

src/qtractorPlugin.cpp

@@ -1742,8 +1742,8 @@ bool qtractorPlugin::savePluginFilename (
 	if (typeHint == qtractorPluginType::Lv2)
 		return true;
 
-	// Otherwise search for a match
-	// with one of the search paths...
+	// First we search for a match with
+	// one of the plugin search paths...
 	qtractorPluginFactory *pPluginFactory
 		= qtractorPluginFactory::getInstance();
 	if (pPluginFactory) {
@@ -1757,8 +1757,15 @@ bool qtractorPlugin::savePluginFilename (
 		}
 	}
 
-	// No match is found, leave filename as is.
-	return true;
+	// No match is found, force plugin relative path...
+	qtractorSession *pSession = qtractorSession::getInstance();
+	if (pSession) {
+		sFilename = pSession->relativeFilePath(sFilename);
+		return true;
+	}
+
+	// Might never reach here!...
+	return false;
 }
 
 
@@ -2699,17 +2706,30 @@ bool qtractorPluginList::loadPluginFilename (
 	if (typeHint == qtractorPluginType::Lv2)
 		return true;
 
-	// Primary check for plugin pathname...
+	// Primary check for the original plugin path...
 	QFileInfo fi(sFilename);
 	if (fi.exists() && fi.isReadable())
 		return true;
 
+	// Secondary check for a plugin relative path...
+	const bool bRelative = fi.isRelative();
+	if (bRelative) {
+		qtractorSession *pSession = qtractorSession::getInstance();
+		if (pSession) {
+			fi.setFile(pSession->absoluteFilePath(sFilename));
+			if (fi.exists() && fi.isReadable()) {
+				sFilename = fi.absoluteFilePath();
+				return true;
+			}
+		}
+	}
+
 	// Otherwise search for an alternative
-	// under each respective search paths...
+	// under one of the plugin search paths...
 	qtractorPluginFactory *pPluginFactory
 		= qtractorPluginFactory::getInstance();
 	if (pPluginFactory) {
-		const QString& fname = (fi.isRelative() ? sFilename : fi.fileName());
+		const QString& fname = (bRelative ? sFilename : fi.fileName());
 		QStringListIterator iter(pPluginFactory->pluginPaths(typeHint));
 		while (iter.hasNext()) {
 			fi.setFile(QDir(iter.next()), fname);