feat(config): Reference values defined in Xresources

Add config tag to reference a value defined in the Xresource db

`parameter = ${xrdb:var_name}`

CMakeLists.txt

@@ -88,11 +88,12 @@ find_package(Boost REQUIRED)
 find_package(Threads REQUIRED)
 find_package(Freetype REQUIRED Freetype2)
 find_package(PkgConfig)
-find_package(X11 REQUIRED COMPONENTS Xft)
+find_package(X11 REQUIRED COMPONENTS Xft Xutil)
 find_package(X11_XCB REQUIRED)
 
 pkg_check_modules(FONTCONFIG REQUIRED fontconfig)
 
+link_libraries(${X11_X11_LIB})
 link_libraries(${X11_Xft_LIB})
 link_libraries(${X11_XCB_LIB})
 link_libraries(${BOOST_LIBRARIES})

include/components/config.hpp

@@ -6,6 +6,7 @@
 
 #include "common.hpp"
 #include "components/logger.hpp"
+#include "components/x11/xresources.hpp"
 #include "utils/file.hpp"
 #include "utils/string.hpp"
 
@@ -24,7 +25,8 @@ class config {
   /**
    * Construct config
    */
-  explicit config(const logger& logger) : m_logger(logger) {}
+  explicit config(const logger& logger, const xresource_manager& xrm)
+      : m_logger(logger), m_xrm(xrm) {}
 
   /**
    * Load configuration and validate bar section
@@ -181,13 +183,17 @@ class config {
    */
   template <typename T = const config&>
   static di::injector<T> configure() {
-    return di::make_injector(logger::configure());
+    return di::make_injector(logger::configure(), xresource_manager::configure());
   }
 
  protected:
   /**
    * Find value of a config parameter defined as a reference
    * variable using ${section.param} or ${env:VAR}
+   * ${self.key} may be used to reference the current bar section
+   *
+   * @deprecated: ${BAR.key} has been replaced with ${self.key}
+   * but the former is kept to avoid breaking current configs
    */
   template <typename T>
   T dereference_var(string ref_section, string ref_key, string var, const T ref_val) const {
@@ -205,12 +211,25 @@ class config {
       return ref_val;
     }
 
+    if (path.find("xrdb:") == 0) {
+      if (std::is_same<string, T>())
+        return boost::lexical_cast<T>(m_xrm.get_string(path.substr(5)));
+      else if (std::is_same<float, T>())
+        return boost::lexical_cast<T>(m_xrm.get_float(path.substr(5)));
+      else if (std::is_same<int, T>())
+        return boost::lexical_cast<T>(m_xrm.get_int(path.substr(5)));
+    }
+
     auto ref_path = build_path(ref_section, ref_key);
 
     if ((n = path.find(".")) == string::npos)
       throw value_error("Invalid reference defined at [" + ref_path + "]");
 
-    auto section = string_util::replace(path.substr(0, n), "BAR", bar_section());
+    auto section = path.substr(0, n);
+
+    section = string_util::replace(section, "BAR", bar_section());
+    section = string_util::replace(section, "self", bar_section());
+
     auto key = path.substr(n + 1, path.length() - n - 1);
     auto val = m_ptree.get_optional<T>(build_path(section, key));
 
@@ -224,6 +243,7 @@ class config {
 
  private:
   const logger& m_logger;
+  const xresource_manager& m_xrm;
   ptree m_ptree;
   string m_file;
   string m_current_bar;

include/components/x11/xlib.hpp

@@ -3,7 +3,6 @@
 #include <X11/Xutil.h>
 
 #include "common.hpp"
-#include "components/x11/xutils.hpp"
 
 LEMONBUDDY_NS
 

include/components/x11/xresources.hpp

@@ -0,0 +1,66 @@
+#pragma once
+
+#include <X11/Xlib.h>
+#include <X11/Xresource.h>
+
+#include "common.hpp"
+#include "components/x11/xlib.hpp"
+
+LEMONBUDDY_NS
+
+class xresource_manager {
+ public:
+  explicit xresource_manager() {
+    XrmInitialize();
+
+    if (xlib::get_display() == nullptr)
+      return;
+    if ((m_manager = XResourceManagerString(xlib::get_display())) == nullptr)
+      return;
+    if ((m_db = XrmGetStringDatabase(m_manager)) == nullptr)
+      return;
+  }
+
+  /**
+   * Configure injection module
+   */
+  template <typename T = const xresource_manager&>
+  static di::injector<T> configure() {
+    auto instance = factory::generic_singleton<xresource_manager>();
+    return di::make_injector(di::bind<>().to(instance));
+  }
+
+  string get_string(string name) const {
+    return load_value(name, "String", 64);
+  }
+
+  float get_float(string name) const {
+    return std::strtof(load_value(name, "String", 64).c_str(), 0);
+  }
+
+  int get_int(string name) const {
+    return std::atoi(load_value(name, "String", 64).c_str());
+  }
+
+ protected:
+  string load_value(string key, string res_type, size_t n) const {
+    if (m_manager == nullptr)
+      return "";
+
+    char* type = nullptr;
+    XrmValue ret;
+    XrmGetResource(m_db, key.c_str(), res_type.c_str(), &type, &ret);
+
+    if (ret.addr != nullptr && !std::strncmp(res_type.c_str(), type, n)) {
+      return {ret.addr};
+    }
+
+    return "";
+  }
+
+ private:
+  char* m_manager = nullptr;
+  XrmDatabase m_db;
+};
+
+LEMONBUDDY_NS_END