Templatify module factory

Saves us a lot of code duplication by generating module type-indexed map
and factory functions from the module class names.

include/modules/meta/all.hpp

@@ -0,0 +1,49 @@
+#pragma once
+
+/**
+ * Header file to include the headers for all modules.
+ */
+
+#include "modules/backlight.hpp"
+#include "modules/battery.hpp"
+#include "modules/bspwm.hpp"
+#include "modules/counter.hpp"
+#include "modules/cpu.hpp"
+#include "modules/date.hpp"
+#include "modules/fs.hpp"
+#include "modules/ipc.hpp"
+#include "modules/memory.hpp"
+#include "modules/menu.hpp"
+#include "modules/meta/base.hpp"
+#include "modules/script.hpp"
+#if DEBUG
+#include "modules/systray.hpp"
+#endif
+#include "modules/temperature.hpp"
+#include "modules/text.hpp"
+#include "modules/tray.hpp"
+#include "modules/xbacklight.hpp"
+#include "modules/xwindow.hpp"
+#include "modules/xworkspaces.hpp"
+#if ENABLE_I3
+#include "modules/i3.hpp"
+#endif
+#if ENABLE_MPD
+#include "modules/mpd.hpp"
+#endif
+#if ENABLE_NETWORK
+#include "modules/network.hpp"
+#endif
+#if ENABLE_ALSA
+#include "modules/alsa.hpp"
+#endif
+#if ENABLE_PULSEAUDIO
+#include "modules/pulseaudio.hpp"
+#endif
+#if ENABLE_CURL
+#include "modules/github.hpp"
+#endif
+#if ENABLE_XKEYBOARD
+#include "modules/xkeyboard.hpp"
+#endif
+#include "modules/unsupported.hpp"

include/modules/meta/factory.hpp

@@ -1,115 +1,24 @@
 #pragma once
 
 #include "common.hpp"
-#include "modules/backlight.hpp"
-#include "modules/battery.hpp"
-#include "modules/bspwm.hpp"
-#include "modules/counter.hpp"
-#include "modules/cpu.hpp"
-#include "modules/date.hpp"
-#include "modules/fs.hpp"
-#include "modules/ipc.hpp"
-#include "modules/memory.hpp"
-#include "modules/menu.hpp"
+#include "components/logger.hpp"
+#include "components/types.hpp"
 #include "modules/meta/base.hpp"
-#include "modules/script.hpp"
-#if DEBUG
-#include "modules/systray.hpp"
-#endif
-#include "modules/temperature.hpp"
-#include "modules/text.hpp"
-#include "modules/tray.hpp"
-#include "modules/xbacklight.hpp"
-#include "modules/xwindow.hpp"
-#include "modules/xworkspaces.hpp"
-#if ENABLE_I3
-#include "modules/i3.hpp"
-#endif
-#if ENABLE_MPD
-#include "modules/mpd.hpp"
-#endif
-#if ENABLE_NETWORK
-#include "modules/network.hpp"
-#endif
-#if ENABLE_ALSA
-#include "modules/alsa.hpp"
-#endif
-#if ENABLE_PULSEAUDIO
-#include "modules/pulseaudio.hpp"
-#endif
-#if ENABLE_CURL
-#include "modules/github.hpp"
-#endif
-#if ENABLE_XKEYBOARD
-#include "modules/xkeyboard.hpp"
-#endif
-#include "modules/unsupported.hpp"
 
 POLYBAR_NS
 
-using namespace modules;
+namespace modules {
+  using module_t = shared_ptr<module_interface>;
 
-namespace {
-  module_interface* make_module(string&& name, const bar_settings& bar, string module_name, const logger& m_log) {
-    if (name == counter_module::TYPE) {
-      return new counter_module(bar, move(module_name));
-    } else if (name == backlight_module::TYPE) {
-      return new backlight_module(bar, move(module_name));
-    } else if (name == battery_module::TYPE) {
-      return new battery_module(bar, move(module_name));
-    } else if (name == bspwm_module::TYPE) {
-      return new bspwm_module(bar, move(module_name));
-    } else if (name == cpu_module::TYPE) {
-      return new cpu_module(bar, move(module_name));
-    } else if (name == date_module::TYPE) {
-      return new date_module(bar, move(module_name));
-    } else if (name == github_module::TYPE) {
-      return new github_module(bar, move(module_name));
-    } else if (name == fs_module::TYPE) {
-      return new fs_module(bar, move(module_name));
-    } else if (name == memory_module::TYPE) {
-      return new memory_module(bar, move(module_name));
-    } else if (name == i3_module::TYPE) {
-      return new i3_module(bar, move(module_name));
-    } else if (name == mpd_module::TYPE) {
-      return new mpd_module(bar, move(module_name));
-    } else if (name == "internal/volume") {
-      m_log.warn("internal/volume is deprecated, use %s instead", string(alsa_module::TYPE));
-      return new alsa_module(bar, move(module_name));
-    } else if (name == alsa_module::TYPE) {
-      return new alsa_module(bar, move(module_name));
-    } else if (name == pulseaudio_module::TYPE) {
-      return new pulseaudio_module(bar, move(module_name));
-    } else if (name == network_module::TYPE) {
-      return new network_module(bar, move(module_name));
-#if DEBUG
-    } else if (name == systray_module::TYPE) {
-      return new systray_module(bar, move(module_name));
-#endif
-    } else if (name == temperature_module::TYPE) {
-      return new temperature_module(bar, move(module_name));
-    } else if (name == xbacklight_module::TYPE) {
-      return new xbacklight_module(bar, move(module_name));
-    } else if (name == xkeyboard_module::TYPE) {
-      return new xkeyboard_module(bar, move(module_name));
-    } else if (name == xwindow_module::TYPE) {
-      return new xwindow_module(bar, move(module_name));
-    } else if (name == xworkspaces_module::TYPE) {
-      return new xworkspaces_module(bar, move(module_name));
-    } else if (name == tray_module::TYPE) {
-      return new tray_module(bar, move(module_name));
-    } else if (name == text_module::TYPE) {
-      return new text_module(bar, move(module_name));
-    } else if (name == script_module::TYPE) {
-      return new script_module(bar, move(module_name));
-    } else if (name == menu_module::TYPE) {
-      return new menu_module(bar, move(module_name));
-    } else if (name == ipc_module::TYPE) {
-      return new ipc_module(bar, move(module_name));
-    } else {
-      throw application_error("Unknown module: " + name);
-    }
-  }
-}  // namespace
+  /**
+   * Creates a new module instance.
+   *
+   * @param type The type of the module (as given by each module's TYPE field)
+   * @param bar An instance of the @ref bar_settings
+   * @param module_name The user-specified module name
+   * @param log A @ref logger instance
+   */
+  module_t make_module(string&& type, const bar_settings& bar, string module_name, const logger& log);
+} // namespace modules
 
 POLYBAR_NS_END

src/CMakeLists.txt

@@ -94,6 +94,7 @@ set(POLY_SOURCES
   ${src_dir}/modules/memory.cpp
   ${src_dir}/modules/menu.cpp
   ${src_dir}/modules/meta/base.cpp
+  ${src_dir}/modules/meta/factory.cpp
   ${src_dir}/modules/script.cpp
   ${src_dir}/modules/systray.cpp
   ${src_dir}/modules/temperature.cpp

src/components/controller.cpp

@@ -11,6 +11,7 @@
 #include "components/types.hpp"
 #include "events/signal.hpp"
 #include "events/signal_emitter.hpp"
+#include "modules/meta/all.hpp"
 #include "modules/meta/base.hpp"
 #include "modules/meta/event_handler.hpp"
 #include "modules/meta/factory.hpp"
@@ -25,6 +26,7 @@
 POLYBAR_NS
 
 using namespace eventloop;
+using namespace modules;
 
 /**
  * Build controller instance
@@ -624,9 +626,7 @@ size_t controller::setup_modules(alignment align) {
       }
 
       m_log.notice("Loading module '%s' of type '%s'", module_name, type);
-      auto ptr = make_module(move(type), m_bar->settings(), module_name, m_log);
-      module_t module = shared_ptr<modules::module_interface>(ptr);
-      ptr = nullptr;
+      module_t module = modules::make_module(move(type), m_bar->settings(), module_name, m_log);
 
       m_modules.push_back(module);
       m_blocks[align].push_back(module);

src/modules/meta/factory.cpp

@@ -0,0 +1,89 @@
+#include "modules/meta/factory.hpp"
+
+#include "modules/meta/all.hpp"
+
+POLYBAR_NS
+
+namespace modules {
+
+  /**
+   * Function pointer for creating a module.
+   */
+  using factory_fun = module_t (*)(const bar_settings&, string&&);
+  using factory_map = map<string, factory_fun>;
+
+  /**
+   * Creates a factory function for constructing a module.
+   *
+   * @tparam M name of the module class
+   */
+  template <typename M>
+  static constexpr factory_fun get_factory() {
+    return [](const bar_settings& bar, string&& module_name) -> module_t {
+      return make_shared<M>(bar, move(module_name));
+    };
+  }
+
+  /**
+   * Creates an entry for the factories map.
+   *
+   * Each entry is a pair containing the module type and the factory function.
+   *
+   * @tparam M name of the module class
+   */
+  template <typename M>
+  static factory_map::value_type map_entry() {
+    return std::make_pair(std::string(M::TYPE), get_factory<M>());
+  }
+
+  /**
+   * Factory function for each module type.
+   */
+  static const factory_map factories = {
+      map_entry<counter_module>(),
+      map_entry<backlight_module>(),
+      map_entry<battery_module>(),
+      map_entry<bspwm_module>(),
+      map_entry<cpu_module>(),
+      map_entry<date_module>(),
+      map_entry<github_module>(),
+      map_entry<fs_module>(),
+      map_entry<memory_module>(),
+      map_entry<i3_module>(),
+      map_entry<mpd_module>(),
+      map_entry<alsa_module>(),
+      map_entry<pulseaudio_module>(),
+      map_entry<network_module>(),
+#if DEBUG
+      map_entry<systray_module>(),
+#endif
+      map_entry<temperature_module>(),
+      map_entry<xbacklight_module>(),
+      map_entry<xkeyboard_module>(),
+      map_entry<xwindow_module>(),
+      map_entry<xworkspaces_module>(),
+      map_entry<tray_module>(),
+      map_entry<text_module>(),
+      map_entry<script_module>(),
+      map_entry<menu_module>(),
+      map_entry<ipc_module>(),
+  };
+
+  module_t make_module(string&& type, const bar_settings& bar, string module_name, const logger& log) {
+    string actual_type = type;
+
+    if (type == "internal/volume") {
+      log.warn("internal/volume is deprecated, use %s instead", string(alsa_module::TYPE));
+      actual_type = alsa_module::TYPE;
+    }
+
+    auto it = factories.find(actual_type);
+    if (it != factories.end()) {
+      return it->second(bar, std::move(module_name));
+    } else {
+      throw application_error("Unknown module: " + type);
+    }
+  }
+} // namespace modules
+
+POLYBAR_NS_END