Implemented extension of the G-code post-processor framework:

1) New environment variable SLIC3R_PP_HOST contains one of
   "File", "PrusaLink", "Repetier", "SL1Host", "OctoPrint", "FlashAir", "Duet", "AstroBox" ...
2) New environment variable SLIC3R_PP_OUTPUT_NAME contains the name
   of the G-code file including path (for SLIC3R_PP_HOST == "File")
   or a name of the file after upload to the host (PrusaLink, Octoprint ...)
3) The post-processing script may suggest a new output file name
   (likely based on SLIC3R_PP_OUTPUT_NAME) by saving it as a single line
   into a new "output name" temp file. The "output name" file name is
   created by suffixing the input G-code file name with ".output_name".

Please note that the G-code viewer visualizes G-code before post-processing.

Fixes Broken PostProcessing when script changes out-filename #6042

src/libslic3r/GCode/GCodeProcessor.hpp

@@ -337,9 +337,9 @@ namespace Slic3r {
                 std::string printer;
 
                 void reset() {
-                    print = "";
-                    filament = std::vector<std::string>();
-                    printer = "";
+                    print.clear();
+                    filament.clear();
+                    printer.clear();
                 }
             };
             std::string filename;

src/libslic3r/GCode/PostProcessor.cpp

@@ -1,5 +1,7 @@
 #include "PostProcessor.hpp"
 
+#include "libslic3r/Utils.hpp"
+
 #include <boost/algorithm/string.hpp>
 #include <boost/log/trivial.hpp>
 #include <boost/format.hpp>
@@ -179,41 +181,125 @@ static int run_script(const std::string &script, const std::string &gcode, std::
 
 namespace Slic3r {
 
-void run_post_process_scripts(const std::string &path, const DynamicPrintConfig &config)
+// Run post processing script / scripts if defined.
+// Returns true if a post-processing script was executed.
+// Returns false if no post-processing script was defined.
+// Throws an exception on error.
+// host is one of "File", "PrusaLink", "Repetier", "SL1Host", "OctoPrint", "FlashAir", "Duet", "AstroBox" ...
+// For a "File" target, a temp file will be created for src_path by adding a ".pp" suffix and src_path will be updated.
+// In that case the caller is responsible to delete the temp file created.
+// output_name is the final name of the G-code on SD card or when uploaded to PrusaLink or OctoPrint.
+// If uploading to PrusaLink or OctoPrint, then the file will be renamed to output_name first on the target host.
+// The post-processing script may change the output_name.
+bool run_post_process_scripts(std::string &src_path, bool make_copy, const std::string &host, std::string &output_name, const DynamicPrintConfig &config)
 {
-    const auto* post_process = config.opt<ConfigOptionStrings>("post_process");
+    const auto *post_process = config.opt<ConfigOptionStrings>("post_process");
     if (// likely running in SLA mode
         post_process == nullptr || 
         // no post-processing script
         post_process->values.empty())
-        return;
+        return false;
+
+    std::string path;
+    if (make_copy) {
+        // Don't run the post-processing script on the input file, it will be memory mapped by the G-code viewer.
+        // Make a copy.
+        path = src_path + ".pp";
+        // First delete an old file if it exists.
+        try {
+            if (boost::filesystem::exists(path))
+                boost::filesystem::remove(path);
+        } catch (const std::exception &err) {
+            BOOST_LOG_TRIVIAL(error) << Slic3r::format("Failed deleting an old temporary file %1% before running a post-processing script: %2%", path, err.what());
+        }
+        // Second make a copy.
+        std::string error_message;
+        if (copy_file(src_path, path, error_message, false) != SUCCESS)
+            throw Slic3r::RuntimeError(Slic3r::format("Failed making a temporary copy of G-code file %1% before running a post-processing script: %2%", src_path, error_message));
+    } else {
+        // Don't make a copy of the G-code before running the post-processing script.
+        path = src_path;
+    }
+
+    auto delete_copy = [&path, &src_path, make_copy]() {
+        if (make_copy)
+            try {
+                if (boost::filesystem::exists(path))
+                    boost::filesystem::remove(path);
+            } catch (const std::exception &err) {
+                BOOST_LOG_TRIVIAL(error) << Slic3r::format("Failed deleting a temporary copy %1% of a G-code file %2% : %3%", path, src_path, err.what());
+            }
+    };
 
-    // Store print configuration into environment variables.
-    config.setenv_();
     auto gcode_file = boost::filesystem::path(path);
     if (! boost::filesystem::exists(gcode_file))
         throw Slic3r::RuntimeError(std::string("Post-processor can't find exported gcode file"));
 
-    for (const std::string &scripts : post_process->values) {
-		std::vector<std::string> lines;
-		boost::split(lines, scripts, boost::is_any_of("\r\n"));
-        for (std::string script : lines) {
-            // Ignore empty post processing script lines.
-            boost::trim(script);
-            if (script.empty())
-                continue;
-            BOOST_LOG_TRIVIAL(info) << "Executing script " << script << " on file " << path;
-
-            std::string std_err;
-            const int result = run_script(script, gcode_file.string(), std_err);
-            if (result != 0) {
-                const std::string msg = std_err.empty() ? (boost::format("Post-processing script %1% on file %2% failed.\nError code: %3%") % script % path % result).str()
-                    : (boost::format("Post-processing script %1% on file %2% failed.\nError code: %3%\nOutput:\n%4%") % script % path % result % std_err).str();
-                BOOST_LOG_TRIVIAL(error) << msg;
-                throw Slic3r::RuntimeError(msg);
+    // Store print configuration into environment variables.
+    config.setenv_();
+    // Let the post-processing script know the target host ("File", "PrusaLink", "Repetier", "SL1Host", "OctoPrint", "FlashAir", "Duet", "AstroBox" ...)
+    boost::nowide::setenv("SLIC3R_PP_HOST", host.c_str(), 1);
+    // Let the post-processing script know the final file name. For "File" host, it is a full path of the target file name and its location, for example pointing to an SD card.
+    // For "PrusaLink" or "OctoPrint", it is a file name optionally with a directory on the target host.
+    boost::nowide::setenv("SLIC3R_PP_OUTPUT_NAME", output_name.c_str(), 1);
+
+    // Path to an optional file that the post-processing script may create and populate it with a single line containing the output_name replacement.
+    std::string path_output_name = src_path + ".output_name";
+    auto remove_output_name_file = [&path_output_name, &src_path]() {
+        try {
+            if (boost::filesystem::exists(path_output_name))
+                boost::filesystem::remove(path_output_name);
+        } catch (const std::exception &err) {
+            BOOST_LOG_TRIVIAL(error) << Slic3r::format("Failed deleting a file %1% carrying the final name / path of a G-code file %2%: %3%", path_output_name, src_path, err.what());
+        }
+    };
+    // Remove possible stalled path_output_name of the previous run.
+    remove_output_name_file();
+
+    try {
+        for (const std::string &scripts : post_process->values) {
+    		std::vector<std::string> lines;
+    		boost::split(lines, scripts, boost::is_any_of("\r\n"));
+            for (std::string script : lines) {
+                // Ignore empty post processing script lines.
+                boost::trim(script);
+                if (script.empty())
+                    continue;
+                BOOST_LOG_TRIVIAL(info) << "Executing script " << script << " on file " << path;
+                std::string std_err;
+                const int result = run_script(script, gcode_file.string(), std_err);
+                if (result != 0) {
+                    const std::string msg = std_err.empty() ? (boost::format("Post-processing script %1% on file %2% failed.\nError code: %3%") % script % path % result).str()
+                        : (boost::format("Post-processing script %1% on file %2% failed.\nError code: %3%\nOutput:\n%4%") % script % path % result % std_err).str();
+                    BOOST_LOG_TRIVIAL(error) << msg;
+                    delete_copy();
+                    throw Slic3r::RuntimeError(msg);
+                }
+            }
+        }
+        if (boost::filesystem::exists(path_output_name)) {
+            try {
+                // Read a single line from path_output_name, which should contain the new output name of the post-processed G-code.
+                boost::nowide::fstream f;
+                f.open(path_output_name, std::ios::in);
+                std::string new_output_name;
+                std::getline(f, new_output_name);
+                f.close();
+                BOOST_LOG_TRIVIAL(trace) << "Post-processing script changed the file name from " << output_name << " to " << new_output_name;
+                output_name = new_output_name;
+            } catch (const std::exception &err) {
+                BOOST_LOG_TRIVIAL(error) << Slic3r::format("Failed reading a file %1% carrying the final name / path of a G-code file: %2%", path_output_name, err.what());
             }
+            remove_output_name_file();
         }
+    } catch (...) {
+        remove_output_name_file();
+        delete_copy();
+        throw;
     }
+
+    src_path = std::move(path);
+    return true;
 }
 
 } // namespace Slic3r

src/libslic3r/GCode/PostProcessor.hpp

@@ -8,7 +8,23 @@
 
 namespace Slic3r {
 
-extern void run_post_process_scripts(const std::string &path, const DynamicPrintConfig &config);
+// Run post processing script / scripts if defined.
+// Returns true if a post-processing script was executed.
+// Returns false if no post-processing script was defined.
+// Throws an exception on error.
+// host is one of "File", "PrusaLink", "Repetier", "SL1Host", "OctoPrint", "FlashAir", "Duet", "AstroBox" ...
+// If make_copy, then a temp file will be created for src_path by adding a ".pp" suffix and src_path will be updated.
+// In that case the caller is responsible to delete the temp file created.
+// output_name is the final name of the G-code on SD card or when uploaded to PrusaLink or OctoPrint.
+// If uploading to PrusaLink or OctoPrint, then the file will be renamed to output_name first on the target host.
+// The post-processing script may change the output_name.
+extern bool run_post_process_scripts(std::string &src_path, bool make_copy, const std::string &host, std::string &output_name, const DynamicPrintConfig &config);
+
+inline bool run_post_process_scripts(std::string &src_path, const DynamicPrintConfig &config)
+{
+	std::string src_path_name = src_path;
+	return run_post_process_scripts(src_path, false, "File", src_path_name, config);
+}
 
 } // namespace Slic3r
 

src/slic3r/GUI/BackgroundSlicingProcess.cpp

@@ -154,54 +154,7 @@ void BackgroundSlicingProcess::process_fff()
 	if (this->set_step_started(bspsGCodeFinalize)) {
 	    if (! m_export_path.empty()) {
 			wxQueueEvent(GUI::wxGetApp().mainframe->m_plater, new wxCommandEvent(m_event_export_began_id));
-
-			// let the gcode window to unmap the temporary .gcode file (m_temp_output_path)
-			// because the scripts may want to modify it
-			GUI::wxGetApp().plater()->stop_mapping_gcode_window();
-
-			m_print->set_status(95, _utf8(L("Running post-processing scripts")));
-			run_post_process_scripts(m_temp_output_path, m_fff_print->full_print_config());
-
-			// let the gcode window to reload and remap the temporary .gcode file (m_temp_output_path)
-			GUI::wxGetApp().plater()->start_mapping_gcode_window();
-
-			//FIXME localize the messages
-			// Perform the final post-processing of the export path by applying the print statistics over the file name.
-			std::string export_path = m_fff_print->print_statistics().finalize_output_path(m_export_path);
-			std::string error_message;
-			int copy_ret_val = CopyFileResult::SUCCESS;
-			try
-			{
-				copy_ret_val = copy_file(m_temp_output_path, export_path, error_message, m_export_path_on_removable_media);
-			}
-			catch (...)
-			{
-				throw Slic3r::ExportError(_utf8(L("Unknown error occured during exporting G-code.")));
-			}
-			switch (copy_ret_val) {
-			case CopyFileResult::SUCCESS: break; // no error
-			case CopyFileResult::FAIL_COPY_FILE:
-				throw Slic3r::ExportError((boost::format(_utf8(L("Copying of the temporary G-code to the output G-code failed. Maybe the SD card is write locked?\nError message: %1%"))) % error_message).str());
-				break;
-			case CopyFileResult::FAIL_FILES_DIFFERENT:
-				throw Slic3r::ExportError((boost::format(_utf8(L("Copying of the temporary G-code to the output G-code failed. There might be problem with target device, please try exporting again or using different device. The corrupted output G-code is at %1%.tmp."))) % export_path).str());
-				break;
-			case CopyFileResult::FAIL_RENAMING:
-				throw Slic3r::ExportError((boost::format(_utf8(L("Renaming of the G-code after copying to the selected destination folder has failed. Current path is %1%.tmp. Please try exporting again."))) % export_path).str());
-				break;
-			case CopyFileResult::FAIL_CHECK_ORIGIN_NOT_OPENED:
-				throw Slic3r::ExportError((boost::format(_utf8(L("Copying of the temporary G-code has finished but the original code at %1% couldn't be opened during copy check. The output G-code is at %2%.tmp."))) % m_temp_output_path % export_path).str());
-				break;
-			case CopyFileResult::FAIL_CHECK_TARGET_NOT_OPENED:
-				throw Slic3r::ExportError((boost::format(_utf8(L("Copying of the temporary G-code has finished but the exported code couldn't be opened during copy check. The output G-code is at %1%.tmp."))) % export_path).str());
-				break;
-			default:
-				throw Slic3r::ExportError(_utf8(L("Unknown error occured during exporting G-code.")));
-				BOOST_LOG_TRIVIAL(error) << "Unexpected fail code(" << (int)copy_ret_val << ") durring copy_file() to " << export_path << ".";
-				break;
-			}
-
-	    	m_print->set_status(100, (boost::format(_utf8(L("G-code file exported to %1%"))) % export_path).str());
+			finalize_gcode();
 	    } else if (! m_upload_job.empty()) {
 			wxQueueEvent(GUI::wxGetApp().mainframe->m_plater, new wxCommandEvent(m_event_export_began_id));
 			prepare_upload();
@@ -621,8 +574,11 @@ Print::ApplyStatus BackgroundSlicingProcess::apply(const Model &model, const Dyn
 		// Some FFF status was invalidated, and the G-code was not exported yet.
 		// Let the G-code preview UI know that the final G-code preview is not valid.
 		// In addition, this early memory deallocation reduces memory footprint.
-		if (m_gcode_result != nullptr)
+		if (m_gcode_result != nullptr) {
+			//FIXME calling platter from here is not a staple of a good architecture.
+			GUI::wxGetApp().plater()->stop_mapping_gcode_window();
 			m_gcode_result->reset();
+		}
 	}
 	return invalidated;
 }
@@ -698,24 +654,89 @@ bool BackgroundSlicingProcess::invalidate_all_steps()
 	return m_step_state.invalidate_all([this](){ this->stop_internal(); });
 }
 
-void BackgroundSlicingProcess::prepare_upload()
-{
-	// A print host upload job has been scheduled, enqueue it to the printhost job queue
+// G-code is generated in m_temp_output_path.
+// Optionally run a post-processing script on a copy of m_temp_output_path.
+// Copy the final G-code to target location (possibly a SD card, if it is a removable media, then verify that the file was written without an error).
+void BackgroundSlicingProcess::finalize_gcode()
+{
+	m_print->set_status(95, _utf8(L("Running post-processing scripts")));
+
+	// Perform the final post-processing of the export path by applying the print statistics over the file name.
+	std::string export_path = m_fff_print->print_statistics().finalize_output_path(m_export_path);
+	std::string output_path = m_temp_output_path;
+	// Both output_path and export_path ar in-out parameters.
+	// If post processed, output_path will differ from m_temp_output_path as run_post_process_scripts() will make a copy of the G-code to not
+	// collide with the G-code viewer memory mapping of the unprocessed G-code. G-code viewer maps unprocessed G-code, because m_gcode_result 
+	// is calculated for the unprocessed G-code and it references lines in the memory mapped G-code file by line numbers.
+	// export_path may be changed by the post-processing script as well if the post processing script decides so, see GH #6042.
+	bool post_processed = run_post_process_scripts(output_path, true, "File", export_path, m_fff_print->full_print_config());
+	auto remove_post_processed_temp_file = [post_processed, &output_path]() {
+		if (post_processed)
+			try {
+				boost::filesystem::remove(output_path);
+			} catch (const std::exception &ex) {
+				BOOST_LOG_TRIVIAL(error) << "Failed to remove temp file " << output_path << ": " << ex.what();
+			}
+	};
 
-	// XXX: is fs::path::string() right?
+	//FIXME localize the messages
+	std::string error_message;
+	int copy_ret_val = CopyFileResult::SUCCESS;
+	try
+	{
+		copy_ret_val = copy_file(output_path, export_path, error_message, m_export_path_on_removable_media);
+		remove_post_processed_temp_file();
+	}
+	catch (...)
+	{
+		remove_post_processed_temp_file();
+		throw Slic3r::ExportError(_utf8(L("Unknown error occured during exporting G-code.")));
+	}
+	switch (copy_ret_val) {
+	case CopyFileResult::SUCCESS: break; // no error
+	case CopyFileResult::FAIL_COPY_FILE:
+		throw Slic3r::ExportError((boost::format(_utf8(L("Copying of the temporary G-code to the output G-code failed. Maybe the SD card is write locked?\nError message: %1%"))) % error_message).str());
+		break;
+	case CopyFileResult::FAIL_FILES_DIFFERENT:
+		throw Slic3r::ExportError((boost::format(_utf8(L("Copying of the temporary G-code to the output G-code failed. There might be problem with target device, please try exporting again or using different device. The corrupted output G-code is at %1%.tmp."))) % export_path).str());
+		break;
+	case CopyFileResult::FAIL_RENAMING:
+		throw Slic3r::ExportError((boost::format(_utf8(L("Renaming of the G-code after copying to the selected destination folder has failed. Current path is %1%.tmp. Please try exporting again."))) % export_path).str());
+		break;
+	case CopyFileResult::FAIL_CHECK_ORIGIN_NOT_OPENED:
+		throw Slic3r::ExportError((boost::format(_utf8(L("Copying of the temporary G-code has finished but the original code at %1% couldn't be opened during copy check. The output G-code is at %2%.tmp."))) % output_path % export_path).str());
+		break;
+	case CopyFileResult::FAIL_CHECK_TARGET_NOT_OPENED:
+		throw Slic3r::ExportError((boost::format(_utf8(L("Copying of the temporary G-code has finished but the exported code couldn't be opened during copy check. The output G-code is at %1%.tmp."))) % export_path).str());
+		break;
+	default:
+		throw Slic3r::ExportError(_utf8(L("Unknown error occured during exporting G-code.")));
+		BOOST_LOG_TRIVIAL(error) << "Unexpected fail code(" << (int)copy_ret_val << ") durring copy_file() to " << export_path << ".";
+		break;
+	}
 
+	m_print->set_status(100, (boost::format(_utf8(L("G-code file exported to %1%"))) % export_path).str());
+}
+
+// A print host upload job has been scheduled, enqueue it to the printhost job queue
+void BackgroundSlicingProcess::prepare_upload()
+{
 	// Generate a unique temp path to which the gcode/zip file is copied/exported
 	boost::filesystem::path source_path = boost::filesystem::temp_directory_path()
 		/ boost::filesystem::unique_path("." SLIC3R_APP_KEY ".upload.%%%%-%%%%-%%%%-%%%%");
 
 	if (m_print == m_fff_print) {
 		m_print->set_status(95, _utf8(L("Running post-processing scripts")));
 		std::string error_message;
-		if (copy_file(m_temp_output_path, source_path.string(), error_message) != SUCCESS) {
+		if (copy_file(m_temp_output_path, source_path.string(), error_message) != SUCCESS)
 			throw Slic3r::RuntimeError(_utf8(L("Copying of the temporary G-code to the output G-code failed")));
-		}
-		run_post_process_scripts(source_path.string(), m_fff_print->full_print_config());
         m_upload_job.upload_data.upload_path = m_fff_print->print_statistics().finalize_output_path(m_upload_job.upload_data.upload_path.string());
+        // Make a copy of the source path, as run_post_process_scripts() is allowed to change it when making a copy of the source file
+        // (not here, but when the final target is a file). 
+        std::string source_path_str = source_path.string();
+        std::string output_name_str = m_upload_job.upload_data.upload_path.string();
+		if (run_post_process_scripts(source_path_str, false, m_upload_job.printhost->get_name(), output_name_str, m_fff_print->full_print_config()))
+			m_upload_job.upload_data.upload_path = output_name_str;
     } else {
         m_upload_job.upload_data.upload_path = m_sla_print->print_statistics().finalize_output_path(m_upload_job.upload_data.upload_path.string());