CommanDelete: Fixed pattern match and added dry-run mode

cli/commanddelete.cpp

@@ -9,9 +9,13 @@
 int CommandDelete::handle(QStringList arguments)
 {
 	QCommandLineParser parser;
-	parser.addOptions({{{"v", "verbose"}, "Print path of the files while deleting them"},
+	parser.addOptions(
-					   {"pattern", "Only delete files from index matching the pattern, e. g. */.git/*", "pattern"},
+		{{{"v", "verbose"}, "Print path of the files while deleting them"},
-					   {"deleted", "Delete all files from the index that don't exist anymore"}});
+		 {{"n", "dry-run"}, "Only print which files would be deleted from the database, don't delete them"},
+		 {"pattern",
+		  "Only delete files from index matching the pattern, e. g. */.git/*. Only applies to --deleted or standalone.",
+		  "pattern"},
+		 {"deleted", "Delete all files from the index that don't exist anymore"}});
 
 	parser.addHelpOption();
 	parser.addPositionalArgument("delete", "Delete paths from the index", "delete [paths...]");
@@ -19,6 +23,7 @@ int CommandDelete::handle(QStringList arguments)
 	parser.process(arguments);
 	bool removeNonExistant = parser.isSet("deleted");
 	bool verbose = parser.isSet("verbose");
+	bool dryRun = parser.isSet("dry-run");
 	QString pattern = parser.value("pattern");
 
 	// TODO: port this to QRegularExpression once >5.12 gets more widespread because of this bug
@@ -34,7 +39,7 @@ int CommandDelete::handle(QStringList arguments)
 
 	if(removeNonExistant)
 	{
-		// TODO: try to translate pattern to SQL WHERE
+		// TODO: try to translate pattern to SQL WHERE statement
 		QSqlQuery pathsQuery("SELECT path FROM file", db);
 		if(!pathsQuery.exec())
 		{
@@ -45,21 +50,33 @@ int CommandDelete::handle(QStringList arguments)
 		while(pathsQuery.next())
 		{
 			QString path = pathsQuery.value(0).toString();
-			if(usePattern && regexPattern.exactMatch(path))
+			bool removeFile = true;
+			if(usePattern)
+			{
+				removeFile = regexPattern.exactMatch(path);
+			}
+			if(removeFile)
 			{
 				QFile file(path);
 				if(!file.exists())
 				{
-					QSqlQuery query("DELETE FROM file WHERE path = ?", db);
+					if(!dryRun)
-					query.addBindValue(path);
-					if(!query.exec())
 					{
-						qDebug() << "Failed to delete " << path << query.lastError();
+						QSqlQuery query("DELETE FROM file WHERE path = ?", db);
-						return 1;
+						query.addBindValue(path);
+						if(!query.exec())
+						{
+							qDebug() << "Failed to delete " << path << query.lastError();
+							return 1;
+						}
+						if(verbose)
+						{
+							qInfo() << "Deleted " << path;
+						}
 					}
-					if(verbose)
+					else
 					{
-						qInfo() << "Deleted " << path;
+						qInfo() << "Would delete " << path;
 					}
 				}
 			}
@@ -73,18 +90,21 @@ int CommandDelete::handle(QStringList arguments)
 		QString absPath = fileInfo.absoluteFilePath();
 		if(fileExistsInDatabase(db, absPath))
 		{
-			QSqlQuery deletionQuery("DELETE FROM file WHERE path = ?", db);
+			if(!dryRun)
-			deletionQuery.addBindValue(absPath);
-			if(deletionQuery.exec())
 			{
-				if(verbose)
+				QSqlQuery deletionQuery("DELETE FROM file WHERE path = ?", db);
+				deletionQuery.addBindValue(absPath);
+				if(deletionQuery.exec())
 				{
-					qInfo() << "Deleted" << absPath;
+					if(verbose)
+					{
+						qInfo() << "Deleted" << absPath;
+					}
+				}
+				else
+				{
+					qDebug() << "Failed to delete:" << absPath << deletionQuery.lastError();
 				}
-			}
-			else
-			{
-				qDebug() << "Failed to delete:" << absPath << deletionQuery.lastError();
 			}
 		}
 		else