refactored to use plugins, possibly requested from command line

main.cpp

@@ -6,26 +6,33 @@
 // Copyright (c) 2020 SwiftCoder. All rights reserved.
 //
 
+// C++
 #include <iostream>
 #include <cstdlib>
 #include <string>
 #include <stdexcept>
-#include <getopt.h>
-#include <libscgui.hpp>
-#include <unistd.h>
-#include <cairo/cairo.h>
 #include <time.h>
-#include <libscerror.hpp>
 #include <cmath>
 #include <thread>
-#include "RectSaver.hpp"
+
+// POSIX
+#include <getopt.h>
+#include <unistd.h>
+
+// libraries
+#include <cairo/cairo.h>
+#include <libscgui.hpp>
+#include <libscerror.hpp>
+#include <libscscreensaver.hpp>
+#include <libscstring.hpp>
+#include <sc/plugin.hpp>
 
 const int WIDTH {1600};
 const int HEIGHT {900};
 
 sc::gui::Window* main_window {nullptr};
 sc::gui::Image* main_image {nullptr};
-RectSaver* main_saver {nullptr};
+ScreensaverPlugin* main_saver {nullptr};
 bool expired {true};
 bool should_run {true};
 
@@ -39,6 +46,12 @@ void print_version() {
     std::cout << "screensaver version 1.0\n";
 }
 
+void list_plugins() {
+    for (const std::string& name : sc::plugin<ScreensaverPlugin>::names()) {
+        std::cout << name << '\n';
+    }
+}
+
 void update_frame() {
     while (should_run) {
         expired = true;
@@ -61,13 +74,18 @@ void draw() {
 
 int main(int argc, const char * argv[]) {
     try {
+        // gather plugins
+        sc::plugin<ScreensaverPlugin>::scan_plugins(sc::dirname(sc::tool_path(argv[0])) + "/plugins", "saver");
+        std::unique_ptr<ScreensaverPlugin> saver;
+
         int opt_char, opt_val;
         struct option long_options[] = {
         {"help", no_argument, nullptr, 'h'},
+        {"list", no_argument, nullptr, 'l'},
             {"version", no_argument, &opt_val, 1},
             {nullptr, 0, nullptr, 0}
         };
-        while ((opt_char = getopt_long(argc, const_cast<char* const *>(argv), "h", long_options, nullptr)) != -1) {
+        while ((opt_char = getopt_long(argc, const_cast<char* const *>(argv), "hl", long_options, nullptr)) != -1) {
             std::string arg {optarg ? optarg : ""};
             switch (opt_char) {
                 case 0: {
@@ -82,20 +100,28 @@ int main(int argc, const char * argv[]) {
                 case 'h':
                     print_help();
                     return EXIT_SUCCESS;
+                case 'l':
+                    list_plugins();
+                    return EXIT_SUCCESS;
                 case '?':
                     throw std::runtime_error("unrecognized option");
             }
         }
-        // if (optind == argc) {
-        //     // here when no file args
-        // }
-        // for (int i = optind; i < argc; ++i) {
-        //     try {
-        //         // process file argv[i]
-        //     } catch (const std::runtime_error& ex) {
-        //         std::cerr << "screensaver: " << ex.what() << '\n';
-        //     }
-        // }
+        if (optind == argc) {
+            // here when no file args
+            saver = sc::plugin<ScreensaverPlugin>::get("rects")();
+        }
+        for (int i = optind; i < argc; ++i) {
+            try {
+                // process file argv[i]
+                saver = sc::plugin<ScreensaverPlugin>::get(argv[i])();
+                break; // only first one used
+            } catch (const std::runtime_error& ex) {
+                std::cerr << "screensaver: " << ex.what() << '\n';
+            } catch (const std::out_of_range& ex) {
+                std::cerr << "screensaver: no such screensaver module: " << argv[i] << '\n';
+            }
+        }
 
         // RAII instances
         sc::gui::SDLWrapper sdl2;
@@ -109,15 +135,23 @@ int main(int argc, const char * argv[]) {
             return quit;
         }, SDL_WINDOWEVENT_CLOSE);
 
+        // create an SDL drawing surface and connect it to cairo
         SDL_Surface* s {SDL_CreateRGBSurface(0, WIDTH, HEIGHT, 32, 0x00ff0000, 0x0000ff00, 0x000000ff, 0)};
         sc::gui::Image image {s};
         main_image = &image;
         cairo_surface_t* cs {cairo_image_surface_create_for_data(static_cast<unsigned char*>(s->pixels),
                                                                  CAIRO_FORMAT_RGB24, s->w, s->h, s->pitch)};
+        std::unique_ptr<cairo_surface_t, void(*)(cairo_surface_t*)> cs_ {cs, cairo_surface_destroy};
         cairo_t* cr {cairo_create(cs)};
+        std::unique_ptr<cairo_t, void(*)(cairo_t*)> cr_ {cr, cairo_destroy};
 
-        RectSaver saver {cr, {0, 0, WIDTH, HEIGHT}};
-        main_saver = &saver;
+        // setup screen saver module
+        if (!saver) {
+            saver = sc::plugin<ScreensaverPlugin>::get("rects")();
+            std::cerr << "screensaver: using standard 'rects' module\n";
+        }
+        main_saver = saver.get();
+        main_saver->setup(cr, {0, 0, WIDTH, HEIGHT});
 
         // setup thread which periodically sets 'expired'
         std::thread frame_timer {update_frame};
@@ -125,9 +159,6 @@ int main(int argc, const char * argv[]) {
         sc::gui::app().add_run_loop_action(draw);
         sc::gui::app().run();
 
-        cairo_surface_destroy(cs);
-        cairo_destroy(cr);
-
         should_run = false;
         frame_timer.join();