Fixed an issue, where the output G-code file name was not always updated

from the current Model/ModelObjects.
Fixed a possible race condition in updating Print::m_placeholder_parser
with the proposed filename / filename base.
Improved documentation (source code comments).

src/libslic3r/GCode.cpp

@@ -717,6 +717,7 @@ void GCode::_do_export(Print &print, FILE *file)
     // Prepare the helper object for replacing placeholders in custom G-code and output filename.
     m_placeholder_parser = print.placeholder_parser();
     m_placeholder_parser.update_timestamp();
+    print.update_object_placeholders(m_placeholder_parser.config_writable());
 
     // Get optimal tool ordering to minimize tool switches of a multi-exruder print.
     // For a print by objects, find the 1st printing object.

src/libslic3r/GCode/CoolingBuffer.cpp

@@ -252,8 +252,10 @@ float new_feedrate_to_reach_time_stretch(
 			for (size_t i = 0; i < (*it)->n_lines_adjustable; ++i) {
 				const CoolingLine &line = (*it)->lines[i];
                 if (line.feedrate > min_feedrate && line.feedrate < new_feedrate)
-                    // Some of the line segments taken into account in the calculation of nomin / denom are now slower than new_feedrate.
-                    // Re-run the calculation with a new min_feedrate limit.
+                    // Some of the line segments taken into account in the calculation of nomin / denom are now slower than new_feedrate, 
+                    // which makes the new_feedrate lower than it should be.
+                    // Re-run the calculation with a new min_feedrate limit, so that the segments with current feedrate lower than new_feedrate
+                    // are not taken into account.
                     goto not_finished_yet;
             }
         goto finished;

src/libslic3r/Model.cpp

@@ -547,13 +547,26 @@ void Model::reset_auto_extruder_id()
     s_auto_extruder_id = 1;
 }
 
-std::string Model::propose_export_file_name() const
+// Propose a filename including path derived from the ModelObject's input path.
+// If object's name is filled in, use the object name, otherwise use the input name.
+std::string Model::propose_export_file_name_and_path() const
 {
     std::string input_file;
     for (const ModelObject *model_object : this->objects)
         for (ModelInstance *model_instance : model_object->instances)
             if (model_instance->is_printable()) {
-                input_file = model_object->name.empty() ? model_object->input_file : model_object->name;
+                input_file = model_object->input_file;
+                if (! model_object->name.empty()) {
+                    if (input_file.empty())
+                        // model_object->input_file was empty, just use model_object->name
+                        input_file = model_object->name;
+                    else {
+                        // Replace file name in input_file with model_object->name, but keep the path and file extension.
+						input_file = (boost::filesystem::path(model_object->name).parent_path().empty()) ?
+							(boost::filesystem::path(input_file).parent_path() / model_object->name).make_preferred().string() :
+							model_object->name;
+					}
+                }
                 if (! input_file.empty())
                     goto end;
                 // Other instances will produce the same name, skip them.

src/libslic3r/Model.hpp

@@ -607,8 +607,8 @@ public:
     static std::string get_auto_extruder_id_as_string(unsigned int max_extruders);
     static void reset_auto_extruder_id();
 
-    // Propose an output file name based on the first printable object's name.
-    std::string         propose_export_file_name() const;
+    // Propose an output file name & path based on the first printable object's name and source input file's path.
+    std::string         propose_export_file_name_and_path() const;
 
 private:
     MODELBASE_DERIVED_PRIVATE_COPY_MOVE(Model)

src/libslic3r/PlaceholderParser.hpp

@@ -32,7 +32,8 @@ public:
     void set(const std::string &key, double value)              { this->set(key, new ConfigOptionFloat(value)); }
     void set(const std::string &key, const std::vector<std::string> &values) { this->set(key, new ConfigOptionStrings(values)); }
     void set(const std::string &key, ConfigOption *opt)         { m_config.set_key_value(key, opt); }
-    const DynamicConfig&    config() const                      { return m_config; }
+	DynamicConfig&			config_writable()					{ return m_config; }
+	const DynamicConfig&    config() const                      { return m_config; }
     const ConfigOption*     option(const std::string &key) const { return m_config.option(key); }
 
     // Fill in the template using a macro processing language.

src/libslic3r/Print.cpp

@@ -421,8 +421,6 @@ void Print::add_model_object(ModelObject* model_object, int idx)
         src_normalized.normalize();
         object->config_apply(src_normalized, true);
     }
-    
-    this->update_object_placeholders();
 }
 
 bool Print::apply_config(DynamicPrintConfig config)
@@ -1096,9 +1094,6 @@ Print::ApplyStatus Print::apply(const Model &model, const DynamicPrintConfig &co
         }
     }
 
-    //FIXME there may be a race condition with the G-code export running at the background thread.
-    this->update_object_placeholders();
-
 #ifdef _DEBUG
     check_model_ids_equal(m_model, model);
 #endif /* _DEBUG */
@@ -1855,6 +1850,9 @@ int Print::get_extruder(const ExtrusionEntityCollection& fill, const PrintRegion
                                     std::max<int>(region.config().perimeter_extruder.value - 1, 0);
 }
 
+// Generate a recommended G-code output file name based on the format template, default extension, and template parameters
+// (timestamps, object placeholders derived from the model, current placeholder prameters and print statistics.
+// Use the final print statistics if available, or just keep the print statistics placeholders if not available yet (before G-code is finalized).
 std::string Print::output_filename() const 
 { 
     // Set the placeholders for the data know first after the G-code export is finished.

src/libslic3r/PrintBase.cpp

@@ -15,7 +15,7 @@ namespace Slic3r
 size_t PrintStateBase::g_last_timestamp = 0;
 
 // Update "scale", "input_filename", "input_filename_base" placeholders from the current m_objects.
-void PrintBase::update_object_placeholders()
+void PrintBase::update_object_placeholders(DynamicConfig &config) const
 {
     // get the first input file name
     std::string input_file;
@@ -33,27 +33,29 @@ void PrintBase::update_object_placeholders()
 				"% y:" + boost::lexical_cast<std::string>(printable->get_scaling_factor(Y) * 100) +
 				"% z:" + boost::lexical_cast<std::string>(printable->get_scaling_factor(Z) * 100) + "%");
 	        if (input_file.empty())
-	            input_file = model_object->input_file;
+	            input_file = model_object->name.empty() ? model_object->input_file : model_object->name;
 	    }
     }
     
-    PlaceholderParser &pp = m_placeholder_parser;
-    pp.set("scale", v_scale);
+    config.set_key_value("year", new ConfigOptionStrings(v_scale));
     if (! input_file.empty()) {
         // get basename with and without suffix
         const std::string input_basename = boost::filesystem::path(input_file).filename().string();
-        pp.set("input_filename", input_basename);
+        config.set_key_value("input_filename", new ConfigOptionString(input_basename));
         const std::string input_basename_base = input_basename.substr(0, input_basename.find_last_of("."));
-        pp.set("input_filename_base", input_basename_base);
+        config.set_key_value("input_filename_base", new ConfigOptionString(input_basename_base));
     }
 }
 
+// Generate an output file name based on the format template, default extension, and template parameters
+// (timestamps, object placeholders derived from the model, current placeholder prameters, print statistics - config_override)
 std::string PrintBase::output_filename(const std::string &format, const std::string &default_ext, const DynamicConfig *config_override) const
 {
     DynamicConfig cfg;
     if (config_override != nullptr)
     	cfg = *config_override;
     PlaceholderParser::update_timestamp(cfg);
+    this->update_object_placeholders(cfg);
     try {
         boost::filesystem::path filename = this->placeholder_parser().process(format, 0, &cfg);
         if (filename.extension().empty())
@@ -69,7 +71,7 @@ std::string PrintBase::output_filepath(const std::string &path) const
     // if we were supplied no path, generate an automatic one based on our first object's input file
     if (path.empty())
         // get the first input file name
-        return (boost::filesystem::path(m_model.propose_export_file_name()).parent_path() / this->output_filename()).make_preferred().string();
+        return (boost::filesystem::path(m_model.propose_export_file_name_and_path()).parent_path() / this->output_filename()).make_preferred().string();
     
     // if we were supplied a directory, use it and append our automatically generated filename
     boost::filesystem::path p(path);

src/libslic3r/PrintBase.hpp

@@ -309,7 +309,7 @@ protected:
     // To be called by this->output_filename() with the format string pulled from the configuration layer.
     std::string            output_filename(const std::string &format, const std::string &default_ext, const DynamicConfig *config_override = nullptr) const;
     // Update "scale", "input_filename", "input_filename_base" placeholders from the current printable ModelObjects.
-    void                   update_object_placeholders();
+    void                   update_object_placeholders(DynamicConfig &config) const;
 
 	Model                                   m_model;
 

src/libslic3r/SLAPrint.cpp

@@ -387,8 +387,6 @@ SLAPrint::ApplyStatus SLAPrint::apply(const Model &model, const DynamicPrintConf
             update_apply_status(false);
     }
 
-    this->update_object_placeholders();
-
 #ifdef _DEBUG
     check_model_ids_equal(m_model, model);
 #endif /* _DEBUG */