logic: Added SourceGroupCustomCommand to use with SourcetrailDB binaries

* Added new Source Group type SourceGroupCustomCommand to UI and ProjectSettings
* The Source Group executes a specified command on every source file
* The variables $SOURCE_PATH, $PROJECT_PATH, $DB_PATH, $STORAGE_VERSION can be passed
* The commands are executed after all other source groups finished indexing
* The command is executed with working directory set to project directory
* Errors during command execution are shown as status update and in the Status View
* SourceGroupCustomCommand cannot be partially cleared, when one file needs clearing the project must be fully re-indexed

src/lib/data/indexer/TaskExecuteCustomCommands.h

@@ -0,0 +1,41 @@
+#ifndef TASK_EXECUTE_CUSTOM_COMMANDS_H
+#define TASK_EXECUTE_CUSTOM_COMMANDS_H
+
+#include <vector>
+
+#include "FilePath.h"
+#include "Task.h"
+#include "TimeStamp.h"
+#include "MessageIndexingInterrupted.h"
+#include "MessageListener.h"
+
+class DialogView;
+class IndexerCommandProvider;
+
+class TaskExecuteCustomCommands
+	: public Task
+	, public MessageListener<MessageIndexingInterrupted>
+{
+public:
+	TaskExecuteCustomCommands(
+		std::unique_ptr<IndexerCommandProvider> indexerCommandProvider,
+		std::shared_ptr<DialogView> dialogView,
+		const FilePath& projectDirectory);
+
+private:
+	void doEnter(std::shared_ptr<Blackboard> blackboard) override;
+	TaskState doUpdate(std::shared_ptr<Blackboard> blackboard) override;
+	void doExit(std::shared_ptr<Blackboard> blackboard) override;
+	void doReset(std::shared_ptr<Blackboard> blackboard) override;
+
+	void handleMessage(MessageIndexingInterrupted* message) override;
+
+	std::unique_ptr<IndexerCommandProvider> m_indexerCommandProvider;
+	std::shared_ptr<DialogView> m_dialogView;
+	const FilePath m_projectDirectory;
+
+	TimeStamp m_start;
+	bool m_interrupted = false;
+};
+
+#endif // TASK_EXECUTE_CUSTOM_COMMANDS_H