DOC: add docstrings

include/caosdb/file_transmission/download_request_handler.h

@@ -68,6 +68,9 @@ using caosdb::entity::v1alpha1::FileTransmissionService;
 using caosdb::transaction::HandlerInterface;
 using caosdb::transaction::HandlerTag;
 
+/*
+ * Handler for the download request of a single file
+ */
 class DownloadRequestHandler final : public HandlerInterface {
 public:
   DownloadRequestHandler(HandlerTag tag, FileTransmissionService::Stub *stub,

include/caosdb/handler_interface.h

@@ -56,7 +56,14 @@
 namespace caosdb::transaction {
 
 const static std::string logger_name = "caosdb::transaction";
-
+/*
+ * Baseclass for UnaryRpcHandler, DownloadRequestHandler and 
+ * UploadRequestHandler
+ *
+ * It handles a request: Its status is contained in the transaction_status
+ * member variable and the functions Start, OnNext and Cancel need to be
+ * overwritten by child classes.
+ */
 class HandlerInterface {
 public:
   HandlerInterface() : transaction_status(TransactionStatus::READY()) {}
@@ -65,6 +72,12 @@ public:
 
   virtual void Start() = 0;
 
+	/*
+	 * ok indicates whether the current request is in a good state or not. If 
+	 * ok is false, the request will be ended.
+	 *
+	 * returns false if the handler is done
+	 */
   virtual bool OnNext(bool ok) = 0;
 
   virtual void Cancel() = 0;

include/caosdb/transaction.h

@@ -432,6 +432,8 @@ public:
 protected:
   /**
    * Await and process the current handler's results.
+   *
+   * This implies consecutive calls to the handler's OnNext function.
    */
   auto ProcessCalls() -> TransactionStatus;