From 56b4657c3f60b9618d8341e3de532e75e9682876 Mon Sep 17 00:00:00 2001
From: Michael Carlberg <c@rlberg.se>
Date: Wed, 19 Oct 2016 14:46:43 +0200
Subject: [PATCH] feat: New module xbacklight

Better implementation for showing backlight information.
This one is using the XRandR extension instead of
reading from the raw file handlers.
---
 include/components/controller.hpp |  11 ++-
 include/components/x11/atoms.hpp  |   6 +-
 include/components/x11/randr.hpp  |  40 +++++++-
 include/modules/backlight.hpp     |  49 ++++-----
 include/modules/xbacklight.hpp    | 159 ++++++++++++++++++++++++++++++
 include/utils/math.hpp            |  18 +++-
 6 files changed, 250 insertions(+), 33 deletions(-)
 create mode 100644 include/modules/xbacklight.hpp

diff --git a/include/components/controller.hpp b/include/components/controller.hpp
index fde2268d..40120498 100644
--- a/include/components/controller.hpp
+++ b/include/components/controller.hpp
@@ -19,6 +19,7 @@
 #include "utils/throttle.hpp"
 
 #include "modules/backlight.hpp"
+#include "modules/xbacklight.hpp"
 #include "modules/battery.hpp"
 #include "modules/bspwm.hpp"
 #include "modules/counter.hpp"
@@ -237,10 +238,14 @@ class controller {
         }
       }
 
+      m_connection.flush();
+
       m_log.trace("controller: Listen for X events");
       while (m_running) {
-        m_connection.flush();
-        m_connection.dispatch_event(m_connection.wait_for_event());
+        auto evt = m_connection.wait_for_event();
+
+        if (evt != nullptr)
+          m_connection.dispatch_event(evt);
       }
     });
 
@@ -375,6 +380,8 @@ class controller {
           modules.emplace_back(new counter_module(bar, m_log, m_conf, module_name));
         else if (type == "internal/backlight")
           modules.emplace_back(new backlight_module(bar, m_log, m_conf, module_name));
+        else if (type == "internal/xbacklight")
+          modules.emplace_back(new xbacklight_module(bar, m_log, m_conf, module_name));
         else if (type == "internal/battery")
           modules.emplace_back(new battery_module(bar, m_log, m_conf, module_name));
         else if (type == "internal/bspwm")
diff --git a/include/components/x11/atoms.hpp b/include/components/x11/atoms.hpp
index af066dea..da4534a5 100644
--- a/include/components/x11/atoms.hpp
+++ b/include/components/x11/atoms.hpp
@@ -31,9 +31,11 @@ static xcb_atom_t MANAGER;
 static xcb_atom_t WM_STATE;
 static xcb_atom_t _NET_SYSTEM_TRAY_ORIENTATION;
 static xcb_atom_t WM_TAKE_FOCUS;
+static xcb_atom_t Backlight;
+static xcb_atom_t BACKLIGHT;
 
 // clang-format off
-static cached_atom ATOMS[22] = {
+static cached_atom ATOMS[24] = {
     {"_NET_WM_NAME", sizeof("_NET_WM_NAME") - 1, &_NET_WM_NAME},
     {"_NET_WM_DESKTOP", sizeof("_NET_WM_DESKTOP") - 1, &_NET_WM_DESKTOP},
     {"_NET_WM_WINDOW_TYPE", sizeof("_NET_WM_WINDOW_TYPE") - 1, &_NET_WM_WINDOW_TYPE},
@@ -56,5 +58,7 @@ static cached_atom ATOMS[22] = {
     {"WM_STATE", sizeof("WM_STATE") - 1, &WM_STATE},
     {"_NET_SYSTEM_TRAY_ORIENTATION", sizeof("_NET_SYSTEM_TRAY_ORIENTATION") - 1, &_NET_SYSTEM_TRAY_ORIENTATION},
     {"WM_TAKE_FOCUS", sizeof("WM_TAKE_FOCUS") - 1, &WM_TAKE_FOCUS},
+    {"Backlight", sizeof("Backlight") - 1, &Backlight},
+    {"BACKLIGHT", sizeof("BACKLIGHT") - 1, &BACKLIGHT},
 };
 // clang-format on
diff --git a/include/components/x11/randr.hpp b/include/components/x11/randr.hpp
index 9d7b2efa..4eb82ea9 100644
--- a/include/components/x11/randr.hpp
+++ b/include/components/x11/randr.hpp
@@ -6,12 +6,20 @@
 
 LEMONBUDDY_NS
 
+struct backlight_values {
+  uint32_t min = 0;
+  uint32_t max = 0;
+  uint32_t val = 0;
+};
+
 struct randr_output {
+  xcb_randr_output_t randr_output;
   string name;
   int w = 0;
   int h = 0;
   int x = 0;
   int y = 0;
+  backlight_values backlight;
 };
 
 using monitor_t = shared_ptr<randr_output>;
@@ -20,8 +28,9 @@ namespace randr_util {
   /**
    * Define monitor
    */
-  inline monitor_t make_monitor(string name, int w, int h, int x, int y) {
+  inline monitor_t make_monitor(xcb_randr_output_t randr, string name, int w, int h, int x, int y) {
     monitor_t mon{new monitor_t::element_type{}};
+    mon->randr_output = randr;
     mon->name = name;
     mon->x = x;
     mon->y = y;
@@ -44,7 +53,7 @@ namespace randr_util {
           continue;
         auto crtc = conn.get_crtc_info(info->crtc);
         string name{info.name().begin(), info.name().end()};
-        monitors.emplace_back(make_monitor(name, crtc->width, crtc->height, crtc->x, crtc->y));
+        monitors.emplace_back(make_monitor(*it, name, crtc->width, crtc->height, crtc->x, crtc->y));
       } catch (const xpp::randr::error::bad_crtc&) {
       } catch (const xpp::randr::error::bad_output&) {
       }
@@ -61,6 +70,33 @@ namespace randr_util {
 
     return monitors;
   }
+
+  inline void get_backlight_range(connection& conn, const monitor_t& mon, backlight_values& dst) {
+    auto reply = conn.query_output_property(mon->randr_output, Backlight);
+
+    if (!reply->range || reply->length != 2)
+      reply = conn.query_output_property(mon->randr_output, BACKLIGHT);
+
+    if (!reply->range || reply->length != 2)
+      return;
+
+    auto range = reply.valid_values().begin();
+
+    dst.min = *range++;
+    dst.max = *range;
+  }
+
+  inline void get_backlight_value(connection& conn, const monitor_t& mon, backlight_values& dst) {
+    auto reply = conn.get_output_property(mon->randr_output, Backlight, XCB_ATOM_NONE, 0, 4, 0, 0);
+
+    if (!reply->num_items)
+      reply = conn.get_output_property(mon->randr_output, BACKLIGHT, XCB_ATOM_NONE, 0, 4, 0, 0);
+
+    if(!reply->num_items)
+      return;
+
+    dst.val = *reply.data().begin();
+  }
 }
 
 LEMONBUDDY_NS_END
diff --git a/include/modules/backlight.hpp b/include/modules/backlight.hpp
index 6a5ba6e0..4a70dfc0 100644
--- a/include/modules/backlight.hpp
+++ b/include/modules/backlight.hpp
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "config.hpp"
+#include "components/config.hpp"
 #include "drawtypes/label.hpp"
 #include "drawtypes/progressbar.hpp"
 #include "drawtypes/ramp.hpp"
@@ -9,6 +10,21 @@
 LEMONBUDDY_NS
 
 namespace modules {
+  struct brightness_handle {
+    void filepath(string path) {
+      if (!file_util::exists(path))
+        throw module_error("The file '" + path + "' does not exist");
+      m_path = path;
+    }
+
+    float read() const {
+      return std::strtof(file_util::get_contents(m_path).c_str(), 0);
+    }
+
+   private:
+    string m_path;
+  };
+
   class backlight_module : public inotify_module<backlight_module> {
    public:
     using inotify_module::inotify_module;
@@ -28,29 +44,22 @@ namespace modules {
         m_ramp = get_config_ramp(m_conf, name(), TAG_RAMP);
 
       // Build path to the file where the current/maximum brightness value is located
-      m_path_val = string_util::replace(PATH_BACKLIGHT_VAL, "%card%", card);
-      m_path_max = string_util::replace(PATH_BACKLIGHT_MAX, "%card%", card);
-
-      if (!file_util::exists(m_path_val))
-        throw module_error("backlight_module: The file '" + m_path_val + "' does not exist");
-      if (!file_util::exists(m_path_max))
-        throw module_error("backlight_module: The file '" + m_path_max + "' does not exist");
+      m_val.filepath(string_util::replace(PATH_BACKLIGHT_VAL, "%card%", card));
+      m_max.filepath(string_util::replace(PATH_BACKLIGHT_MAX, "%card%", card));
 
       // Add inotify watch
       watch(string_util::replace(PATH_BACKLIGHT_VAL, "%card%", card));
     }
 
+    void idle() {
+      sleep(75ms);
+    }
+
     bool on_event(inotify_event* event) {
       if (event != nullptr)
         m_log.trace("%s: %s", name(), event->filename);
 
-      auto val = file_util::get_contents(m_path_val);
-      m_val = std::stoull(val.c_str(), 0, 10);
-
-      auto max = file_util::get_contents(m_path_max);
-      m_max = std::stoull(max.c_str(), 0, 10);
-
-      m_percentage = static_cast<int>(float(m_val) / float(m_max) * 100.0f + 0.5f);
+      m_percentage = static_cast<int>(m_val.read() / m_max.read() * 100.0f + 0.5f);
 
       if (m_label) {
         m_label->reset_tokens();
@@ -72,10 +81,6 @@ namespace modules {
       return true;
     }
 
-    void idle() {
-      this_thread::sleep_for(75ms);
-    }
-
    private:
     static constexpr auto TAG_LABEL = "<label>";
     static constexpr auto TAG_BAR = "<bar>";
@@ -85,12 +90,10 @@ namespace modules {
     label_t m_label;
     progressbar_t m_progressbar;
 
-    string m_path_val;
-    string m_path_max;
-    float m_val = 0;
-    float m_max = 0;
+    brightness_handle m_val;
+    brightness_handle m_max;
 
-    int m_percentage;
+    int m_percentage = 0;
   };
 }
 
diff --git a/include/modules/xbacklight.hpp b/include/modules/xbacklight.hpp
new file mode 100644
index 00000000..6972a5ef
--- /dev/null
+++ b/include/modules/xbacklight.hpp
@@ -0,0 +1,159 @@
+#pragma once
+
+#include "components/config.hpp"
+#include "components/x11/connection.hpp"
+#include "components/x11/randr.hpp"
+#include "components/x11/xutils.hpp"
+#include "config.hpp"
+#include "drawtypes/label.hpp"
+#include "drawtypes/progressbar.hpp"
+#include "drawtypes/ramp.hpp"
+#include "modules/meta.hpp"
+#include "utils/throttle.hpp"
+
+LEMONBUDDY_NS
+
+namespace modules {
+  /**
+   * Backlight module built using the RandR X extension.
+   *
+   * This is built as a replacement for the old backlight
+   * module that was set up using with inotify watches listening
+   * for changes to the raw file handle.
+   *
+   * This module is alot faster, it's more responsive and it will
+   * be dormant until new values are reported. Inotify watches
+   * are a bit random when it comes to proc-/sysfs.
+   *
+   * TODO: Implement backlight configuring using scroll events
+   */
+  class xbacklight_module : public static_module<xbacklight_module>,
+                            public xpp::event::sink<evt::randr_notify> {
+   public:
+    using static_module::static_module;
+
+    /**
+     * Bootstrap the module by grabbing all required components
+     */
+    void setup() {
+      auto output = m_conf.get<string>(name(), "output", m_bar.monitor->name);
+
+      // Grab a list of all outputs and try to find the one defined in the config
+      for (auto&& mon : randr_util::get_monitors(m_connection, m_connection.root())) {
+        if (mon->name == output) {
+          m_output.swap(mon);
+          break;
+        }
+      }
+
+      // If we didn't get a match we stop the module
+      if (!m_output) {
+        throw module_error("No matching output found for \"" + output + "\", stopping module...");
+      }
+
+      // Query randr for the backlight max and min value
+      try {
+        auto& backlight = m_output->backlight;
+        randr_util::get_backlight_range(m_connection, m_output, backlight);
+        randr_util::get_backlight_value(m_connection, m_output, backlight);
+      } catch (const std::exception& err) {
+        throw module_error("No backlight data found for \"" + output + "\", stopping module...");
+      }
+
+      // Connect with the event registry and tell randr that we
+      // want to get notified when an output property gets modified
+      m_connection.attach_sink(this, 1);
+      m_connection.select_input_checked(
+          m_connection.screen()->root, XCB_RANDR_NOTIFY_MASK_OUTPUT_PROPERTY);
+
+      // Create a throttle so that we limit the amount of events
+      // to handle since randr can burst out quite a few
+      // We will allow 1 event per 60 ms. The updates still look smooth
+      // using this setting which is important.
+      m_throttler = throttle_util::make_throttler(1, 60ms);
+
+      // Add formats and elements
+      m_formatter->add(DEFAULT_FORMAT, TAG_LABEL, {TAG_LABEL, TAG_BAR, TAG_RAMP});
+
+      if (m_formatter->has(TAG_LABEL))
+        m_label = get_optional_config_label(m_conf, name(), TAG_LABEL, "%percentage%");
+      if (m_formatter->has(TAG_BAR))
+        m_progressbar = get_config_bar(m_bar, m_conf, name(), TAG_BAR);
+      if (m_formatter->has(TAG_RAMP))
+        m_ramp = get_config_ramp(m_conf, name(), TAG_RAMP);
+
+      // Trigger the initial draw event
+      update();
+    }
+
+    /**
+     * Handler for XCB_RANDR_NOTIFY events
+     */
+    void handle(const evt::randr_notify& evt) {
+      if (evt->subCode != XCB_RANDR_NOTIFY_OUTPUT_PROPERTY)
+        return;
+      else if (evt->u.op.output != m_output->randr_output)
+        return;
+      else if (evt->u.op.atom == Backlight)
+        update();
+      else if (evt->u.op.atom == BACKLIGHT)
+        update();
+    }
+
+    /**
+     * Query the RandR extension for the new values
+     */
+    void update() {
+      // Test if we are allowed to handle the event
+      if (!m_throttler->passthrough(throttle_util::strategy::try_once_or_leave_yolo{}))
+        return;
+
+      // Query for the new backlight value
+      auto& bl = m_output->backlight;
+      randr_util::get_backlight_value(m_connection, m_output, bl);
+      m_percentage = math_util::percentage<float>(bl.val, bl.min, bl.max);
+
+      // Update label tokens
+      if (m_label) {
+        m_label->reset_tokens();
+        m_label->replace_token("%percentage%", to_string(m_percentage) + "%");
+      }
+
+      // Emit a broadcast notification so that
+      // the new data will be drawn to the bar
+      broadcast();
+    }
+
+    /**
+     * Output content as defined in the config
+     */
+    bool build(builder* builder, string tag) const {
+      if (tag == TAG_BAR)
+        builder->node(m_progressbar->output(m_percentage));
+      else if (tag == TAG_RAMP)
+        builder->node(m_ramp->get_by_percentage(m_percentage));
+      else if (tag == TAG_LABEL)
+        builder->node(m_label);
+      else
+        return false;
+      return true;
+    }
+
+   private:
+    static constexpr auto TAG_LABEL = "<label>";
+    static constexpr auto TAG_BAR = "<bar>";
+    static constexpr auto TAG_RAMP = "<ramp>";
+
+    throttle_util::throttle_t m_throttler;
+    connection& m_connection{connection::configure().create<connection&>()};
+    monitor_t m_output;
+
+    ramp_t m_ramp;
+    label_t m_label;
+    progressbar_t m_progressbar;
+
+    int m_percentage = 0;
+  };
+}
+
+LEMONBUDDY_NS_END
diff --git a/include/utils/math.hpp b/include/utils/math.hpp
index 7123a725..bf0f679d 100644
--- a/include/utils/math.hpp
+++ b/include/utils/math.hpp
@@ -6,18 +6,26 @@
 
 LEMONBUDDY_NS
 
-namespace math_util
-{
+namespace math_util {
   /**
    * Limit value T by min and max bounds
    */
-  template<typename T>
-  T cap(T value, T min_value, T max_value)
-  {
+  template <typename T>
+  T cap(T value, T min_value, T max_value) {
     value = std::min<T>(value, max_value);
     value = std::max<T>(value, min_value);
     return value;
   }
+
+  /**
+   * Calculate the percentage for a value
+   * within given range
+   */
+  template <typename T>
+  int percentage(T value, T min_value, T max_value) {
+    T percentage = ((value - min_value) / (max_value - min_value)) * 100.0f + 0.5f;
+    return cap<T>(std::ceil(percentage), 0, 100);
+  }
 }
 
 LEMONBUDDY_NS_END