dmesg: parse arguments and create essential structs.

src/uu/dmesg/src/dmesg.rs

@@ -1,11 +1,70 @@
-use clap::{crate_version, Command};
+use clap::{crate_version, Arg, ArgAction, Command};
 use uucore::error::UResult;
 
 #[uucore::main]
-pub fn uumain(_args: impl uucore::Args) -> UResult<()> {
+pub fn uumain(args: impl uucore::Args) -> UResult<()> {
+    let mut dmesg = Dmesg::new();
+    let matches: clap::ArgMatches = uu_app().try_get_matches_from(args)?;
+    if let Some(kmsg_file) = matches.get_one::<String>(options::KMSG_FILE) {
+        dmesg.kmsg_file = kmsg_file;
+    }
+    if matches.get_flag(options::JSON) {
+        dmesg.output_format = OutputFormat::Json;
+    }
+    dmesg.parse().print();
     Ok(())
 }
 
 pub fn uu_app() -> Command {
-    Command::new(uucore::util_name()).version(crate_version!())
+    Command::new(uucore::util_name())
+        .version(crate_version!())
+        .arg(
+            Arg::new(options::KMSG_FILE)
+                .short('K')
+                .long("kmsg-file")
+                .action(ArgAction::Set),
+        )
+        .arg(
+            Arg::new(options::JSON)
+                .short('J')
+                .long("json")
+                .action(ArgAction::SetTrue),
+        )
+}
+
+mod options {
+    pub const KMSG_FILE: &'static str = "kmsg-file";
+    pub const JSON: &'static str = "json";
+}
+
+struct Dmesg<'a> {
+    kmsg_file: &'a str,
+    output_format: OutputFormat,
+    _records: Option<Vec<Record>>,
+}
+
+impl Dmesg<'_> {
+    fn new() -> Self {
+        Dmesg {
+            kmsg_file: "/dev/kmsg",
+            output_format: OutputFormat::Normal,
+            _records: None,
+        }
+    }
+
+    fn parse(self) -> Self {
+        self
+    }
+
+    fn print(&self) {
+
+    }
+}
+
+enum OutputFormat {
+    Normal,
+    Json,
+}
+
+struct Record {
 }