core: actually add configuration code

This was meant to be included with the YAML configuration support, but
was not. Add it now.

src/core/config.rs

@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ * Copyright (c) 2024, Richard Acayan. All rights reserved.
+ */
+
+use std::convert::TryInto;
+use std::fs::File;
+use yaml_rust2::yaml::Hash;
+use yaml_rust2::yaml::LoadError;
+use yaml_rust2::yaml::YamlDecoder;
+use yaml_rust2::yaml::Yaml;
+
+#[derive(Debug)]
+pub struct Configuration {
+    longpress: u64,
+    repeat: u64,
+    layout: String,
+    wayland_height: i32,
+}
+
+impl Configuration {
+    fn load_wayland(&mut self, yaml: &Hash)
+    {
+        let height = yaml.get(&Yaml::String(String::from("height")));
+        if let Some(height) = height {
+            let height = match height.as_i64() {
+                Some(h) => h.try_into().ok(),
+                None => None,
+            };
+            let height = height.expect("Wayland height should be a 32-bit signed integer");
+            self.wayland_height = height;
+        }
+    }
+
+    pub fn load() -> Result<Self, LoadError>
+    {
+        let mut cfg = Configuration {
+            longpress: 600,
+            repeat: 25,
+            layout: String::from("latn_qwerty_us.xml"),
+            wayland_height: 185,
+        };
+
+        if let Ok(file) = File::open("/etc/unfettered-keyboard.yaml") {
+            let yaml = YamlDecoder::read(file).decode()?;
+            let yaml = yaml[0].as_hash().expect("Top-level configuration should be a YAML mapping");
+
+            let longpress = yaml.get(&Yaml::String(String::from("longpress_ms")));
+            if let Some(longpress) = longpress {
+                let longpress = match longpress.as_i64() {
+                    Some(l) => l.try_into().ok(),
+                    None => None,
+                };
+                let longpress = longpress.expect("Longpress time should be a 64-bit unsigned integer");
+                cfg.longpress = longpress;
+            }
+
+            let repeat = yaml.get(&Yaml::String(String::from("repeat_ms")));
+            if let Some(repeat) = repeat {
+                let repeat = match repeat.as_i64() {
+                    Some(l) => l.try_into().ok(),
+                    None => None,
+                };
+                let repeat = repeat.expect("Repeat interval should be a 64-bit unsigned integer");
+                cfg.repeat = repeat;
+            }
+
+            let layout = yaml.get(&Yaml::String(String::from("layout")));
+            if let Some(layout) = layout {
+                let layout = layout.as_str().expect("Layout should be a YAML string");
+                cfg.layout = layout.to_string();
+            }
+
+            let wl = yaml.get(&Yaml::String(String::from("wayland")));
+            if let Some(wl) = wl {
+                let wl = wl.as_hash().expect("Wayland configuration should be a YAML mapping");
+                cfg.load_wayland(wl);
+            }
+        }
+
+        println!("{:?}", cfg);
+
+        Ok(cfg)
+    }
+
+    #[inline(always)]
+    pub fn longpress_ms(&self) -> u64
+    {
+        self.longpress
+    }
+
+    #[inline(always)]
+    pub fn repeat_ms(&self) -> u64
+    {
+        self.repeat
+    }
+
+    #[inline(always)]
+    pub fn layout(&self) -> &str
+    {
+        &self.layout
+    }
+
+    #[inline(always)]
+    pub fn wayland_height(&self) -> i32
+    {
+        self.wayland_height
+    }
+}