Add a dummy writter for writing to /dev/null

lib/src/H5Writer.cpp

@@ -12,6 +12,16 @@ extern "C"
 
 using namespace std;
 
+std::unique_ptr<H5Writer> get_h5_writer(const string& filename, hsize_t frames_per_file, 
+    hsize_t initial_dataset_size, hsize_t dataset_increase_step)
+{
+    if (filename == "/dev/null") {
+        return unique_ptr<H5Writer>(new DummyH5Writer());
+    } else {
+        return unique_ptr<H5Writer>(new H5Writer(filename, frames_per_file, initial_dataset_size, dataset_increase_step));
+    }
+}
+
 H5Writer::H5Writer(const std::string& filename, hsize_t frames_per_file, hsize_t initial_dataset_size, hsize_t dataset_increase_step) :
     filename(filename), frames_per_file(frames_per_file), 
     initial_dataset_size(initial_dataset_size), dataset_increase_step(dataset_increase_step)
@@ -272,4 +282,25 @@ hsize_t H5Writer::prepare_storage_for_data(const string& dataset_name, const siz
 H5::H5File& H5Writer::get_h5_file() 
 {
     return file;
-}
+}
+
+DummyH5Writer::DummyH5Writer() : H5Writer("/dev/null", 0, 0, 0){}
+
+void DummyH5Writer::close_file(){}
+
+void DummyH5Writer::write_data(const string& dataset_name, const size_t data_index, const char* data, const std::vector<size_t>& data_shape, 
+    const size_t data_bytes_size, const string& data_type, const string& endianness){};
+
+bool DummyH5Writer::is_file_open() const
+{
+    return false;
+}
+
+H5::H5File& DummyH5Writer::get_h5_file(){
+    stringstream error_message;
+    using namespace date;
+    error_message << "[" << std::chrono::system_clock::now() << "]";
+    error_message << "Cannot get the H5 file with the dummy writer." << endl;
+
+    throw runtime_error(error_message.str());
+};

lib/src/H5Writer.hpp

@@ -35,6 +35,17 @@ class H5Writer
     public:
         H5Writer(const std::string& filename, hsize_t frames_per_file=0, hsize_t initial_dataset_size=1000, hsize_t dataset_increase_step=1000);
         virtual ~H5Writer();
+        virtual bool is_file_open() const;
+        virtual void close_file();
+        virtual void write_data(const std::string& dataset_name, const size_t data_index, const char* data, const std::vector<size_t>& data_shape, 
+            const size_t data_bytes_size, const std::string& data_type, const std::string& endianness);
+        virtual H5::H5File& get_h5_file();
+};
+
+class DummyH5Writer : public H5Writer
+{
+    public:
+        DummyH5Writer();
         bool is_file_open() const;
         void close_file();
         void write_data(const std::string& dataset_name, const size_t data_index, const char* data, const std::vector<size_t>& data_shape, 
@@ -42,4 +53,7 @@ class H5Writer
         H5::H5File& get_h5_file();
 };
 
+std::unique_ptr<H5Writer> get_h5_writer(const std::string& filename, hsize_t frames_per_file=0, 
+    hsize_t initial_dataset_size=1000, hsize_t dataset_increase_step=1000);
+
 #endif

lib/src/ProcessManager.cpp

@@ -148,7 +148,7 @@ void ProcessManager::receive_zmq(WriterManager& manager, RingBuffer& ring_buffer
 void ProcessManager::write_h5(WriterManager& manager, const H5Format& format, RingBuffer& ring_buffer,
     const shared_ptr<unordered_map<string, HeaderDataType>> header_values_type, const string& bsread_rest_address)
 {
-    H5Writer writer(manager.get_output_file(), 0, config::initial_dataset_size, config::dataset_increase_step);
+    auto writer = get_h5_writer(manager.get_output_file(), 0, config::initial_dataset_size, config::dataset_increase_step);
     auto raw_frames_dataset_name = config::raw_image_dataset_name;
 
     uint64_t last_pulse_id = 0;
@@ -174,13 +174,13 @@ void ProcessManager::write_h5(WriterManager& manager, const H5Format& format, Ri
         #endif
 
         // Write image data.
-        writer.write_data(raw_frames_dataset_name,
-                          received_data.first->frame_index, 
-                          received_data.second,
-                          received_data.first->frame_shape,
-                          received_data.first->frame_bytes_size, 
-                          received_data.first->type,
-                          received_data.first->endianness);
+        writer->write_data(raw_frames_dataset_name,
+                           received_data.first->frame_index, 
+                           received_data.second,
+                           received_data.first->frame_shape,
+                           received_data.first->frame_bytes_size, 
+                           received_data.first->type,
+                           received_data.first->endianness);
 
         #ifdef PERF_OUTPUT
             using namespace date;
@@ -224,7 +224,7 @@ void ProcessManager::write_h5(WriterManager& manager, const H5Format& format, Ri
                 // Header data are fixed to scalars in little endian.
                 vector<size_t> value_shape = {header_data_type.value_shape};
 
-                writer.write_data(name,
+                writer->write_data(name,
                                   received_data.first->frame_index,
                                   value.get(),
                                   value_shape,
@@ -254,7 +254,7 @@ void ProcessManager::write_h5(WriterManager& manager, const H5Format& format, Ri
         notify_last_pulse_id(bsread_rest_address, last_pulse_id);
     }
 
-    if (writer.is_file_open()) {
+    if (writer->is_file_open()) {
         #ifdef DEBUG_OUTPUT
             using namespace date;
             cout << "[" << std::chrono::system_clock::now() << "]";
@@ -272,7 +272,7 @@ void ProcessManager::write_h5(WriterManager& manager, const H5Format& format, Ri
             
             // Even if we can't write the format, lets try to preserve the data.
             try {
-                H5FormatUtils::write_format(writer.get_h5_file(), format, parameters);
+                H5FormatUtils::write_format(writer->get_h5_file(), format, parameters);
             } catch (const runtime_error& ex) {
                 using namespace date;
                 std::cout << "[" << std::chrono::system_clock::now() << "]";
@@ -287,7 +287,7 @@ void ProcessManager::write_h5(WriterManager& manager, const H5Format& format, Ri
         cout << "[ProcessManager::write] Closing file " << manager.get_output_file() << endl;
     #endif
     
-    writer.close_file();
+    writer->close_file();
 
     #ifdef DEBUG_OUTPUT
         using namespace date;

lib/test/test_H5Writer.cpp

@@ -0,0 +1,12 @@
+
+#include "../src/H5Writer.hpp"
+using namespace std;
+
+TEST(H5Writer, get_h5_writer)
+{
+    auto dummy_writer = get_h5_writer("/dev/null");
+    EXPECT_TRUE(dynamic_cast<DummyH5Writer*>(dummy_writer.get()));
+
+    auto real_writer = get_h5_writer("real_file.h5");
+    EXPECT_FALSE(dynamic_cast<DummyH5Writer*>(real_writer.get()));
+}

lib/test/test_ZmqReceiver.cpp

@@ -1,5 +1,4 @@
 #include "../src/ZmqReceiver.hpp"
-#include "../src/ZmqReceiver.hpp"
 
 using namespace std;
 namespace pt = boost::property_tree;

lib/test/test_main.cpp

@@ -1,5 +1,6 @@
 #include "gtest/gtest.h"
 #include "test_ZmqReceiver.cpp"
+#include "test_H5Writer.cpp"
 
 using namespace std;