1 files changed, 100 insertions, 0 deletions
diff --git a/src/configuration/load.rs b/src/configuration/load.rs
new file mode 100644
index 0000000..a0065fc
--- /dev/null
+++ b/src/configuration/load.rs
@@ -0,0 +1,100 @@
+/*
+	Copyright 2021-2023 Gabriel Jensen.
+
+	This file is part of Luma.
+
+	Luma is free software: you can redistribute it
+	and/or modify it under the terms of the GNU
+	Affero General Public License as published by
+	the Free Software Foundation, either version 3
+	of the License, or (at your option) any later
+	version.
+
+	Luma is distributed in the hope that it will be
+	useful, but WITHOUT ANY WARRANTY; without even
+	the implied warranty of MERCHANTABILITY or
+	FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+	Affero General Public License for more details.
+
+	You should have received a copy of the GNU
+	Affero General Public License along with Luma.
+	If not, see <https://www.gnu.org/licenses/>.
+*/
+
+use crate::configuration::Configuration;
+
+extern crate toml;
+
+use std::fs::read_to_string;
+use std::str::FromStr;
+use toml::{Table, Value};
+
+impl Configuration {
+	pub fn load(path: &str) -> Result<Self, String> {
+		eprintln!("loading configuration at \"{path}\"");
+
+		let configuration_text = match read_to_string(path) {
+			Ok( content) => content,
+			_            => return Err("unable to read file".to_string()),
+		};
+
+		let base_table = match Table::from_str(&configuration_text) {
+			Ok( table) => table,
+			_          => return Err("unable to parse configuration".to_string()),
+		};
+
+		let luma_table   = get_table(&base_table, "luma")?;
+		let device_table = get_table(&base_table, "device")?;
+		let video_table  = get_table(&base_table, "video")?;
+
+		let version = get_integer(&luma_table, "version")?;
+
+		if version < Self::VERSION { return Err(format!("ancient version - got {}, expected {}", version, Self::VERSION)) }
+		if version > Self::VERSION { return Err(format!("out-of-date version - got {}, expected {}", version, Self::VERSION)) }
+
+		let bootloader = get_string(&device_table, "bootloader")?;
+		let image      = get_string(&device_table, "image")?;
+
+		let scale = get_integer(&video_table, "scale")?;
+
+		let configuration = Configuration {
+			bootloader: bootloader.clone(),
+			image:      image.clone(),
+
+			scale: scale,
+		};
+
+		configuration.validate()?;
+		return Ok(configuration);
+	}
+}
+
+fn get_value<'a>(table: &'a Table, name: &str) -> Option<&'a Value> {
+	if !table.contains_key(name) { return None };
+
+	return Some(&table[name]);
+}
+
+fn get_table<'a>(table: &'a Table, name: &str) -> Result<&'a Table, String> {
+	return match get_value(table, name) {
+		Some(Value::Table(table)) => Ok(table),
+		Some(_)                   => Err(format!("\"{name}\" should be a section")),
+		_                         => Err("section \"{name}\" is required".to_string()),
+	};
+}
+
+fn get_integer(table: &Table, name: &str) -> Result<u32, String> {
+	return match get_value(table, name) {
+		Some(Value::Integer(value)) => Ok(*value as u32),
+		Some(_)                     => Err(format!("\"{name}\" should be an integer")),
+		_                           => Err("missing integer \"{name}\"".to_string()),
+	};
+}
+
+fn get_string<'a>(table: &'a Table, name: &str) -> Result<&'a String, String> {
+	return match get_value(table, name) {
+		Some(Value::String(string)) => Ok(string),
+		Some(_)                     => Err(format!("\"{name}\" should be a string")),
+		_                           => Err("missing string \"{name}\"".to_string()),
+	};
+}