lscpu: Add option --json

closes uutils#15

Cargo.toml

@@ -45,6 +45,8 @@ textwrap = { version = "0.16.0", features = ["terminal_size"] }
 xattr = "1.3.1"
 tempfile = "3.9.0"
 rand = { version = "0.8", features = ["small_rng"] }
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"
 
 [dependencies]
 clap = { workspace = true }
@@ -53,7 +55,8 @@ clap_mangen = { workspace = true }
 uucore = { workspace = true }
 phf = { workspace = true }
 textwrap = { workspace = true }
-
+serde = { workspace = true }
+serde_json  = { workspace = true }
 
 #
 lscpu = { optional = true, version = "0.0.1", package = "uu_lscpu", path = "src/uu/lscpu" }

src/uu/lscpu/Cargo.toml

@@ -15,3 +15,5 @@ regex = { workspace = true }
 sysinfo = { workspace = true }
 uucore = { workspace = true }
 clap = { workspace = true }
+serde = { workspace = true }
+serde_json = { workspace = true }

src/uu/lscpu/src/lscpu.rs

@@ -3,31 +3,66 @@
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
 
-use clap::{crate_version, Command};
+use clap::{crate_version, Arg, ArgAction, Command};
 use regex::Regex;
+use serde::Serialize;
+use serde_json;
 use std::fs;
 use sysinfo::System;
 use uucore::{error::UResult, format_usage, help_about, help_usage};
 
+mod options {
+    pub const JSON: &str = "json";
+}
+
 const ABOUT: &str = help_about!("lscpu.md");
 const USAGE: &str = help_usage!("lscpu.md");
 
+#[derive(Serialize)]
+struct Elt {
+    field: String,
+    data: String,
+}
+
 #[uucore::main]
-pub fn uumain(_args: impl uucore::Args) -> UResult<()> {
+pub fn uumain(args: impl uucore::Args) -> UResult<()> {
+    let matches = uu_app().try_get_matches_from(args)?;
+
+    let json = matches.get_flag(options::JSON);
+
     let system = System::new_all();
     let _cpu = system.global_cpu_info();
 
-    println!("Architecture: {}", get_architecture());
-    println!("CPU(s): {}", system.cpus().len());
+    let mut elts: Vec<Elt> = Vec::new();
+    elts.push(Elt {
+        field: String::from("Architecture"),
+        data: String::from(format!("{}", get_architecture())),
+    });
+    elts.push(Elt {
+        field: String::from("CPU(s)"),
+        data: String::from(format!("{}", system.cpus().len())),
+    });
     // Add more CPU information here...
 
     if let Ok(contents) = fs::read_to_string("/proc/cpuinfo") {
         let re = Regex::new(r"^model name\s+:\s+(.*)$").unwrap();
         // Assuming all CPUs have the same model name
         if let Some(cap) = re.captures_iter(&contents).next() {
-            println!("Model name: {}", &cap[1]);
+            elts.push(Elt {
+                field: String::from("Model name"),
+                data: cap[1].to_string(),
+            });
         };
     }
+
+    if json {
+        let json_string = serde_json::to_string(&elts).unwrap();
+        println!("{}", json_string);
+    } else {
+        for elt in &elts {
+            println!("{}: {}", elt.field, elt.data);
+        }
+    }
     Ok(())
 }
 
@@ -47,4 +82,10 @@ pub fn uu_app() -> Command {
         .about(ABOUT)
         .override_usage(format_usage(USAGE))
         .infer_long_args(true)
+        .arg(
+            Arg::new(options::JSON)
+                .long("json")
+                .help("Use JSON output format for the default summary or extended output (see --extended). For backward compatibility, JSON output follows the default summary behavior for non-terminals (e.g., pipes) where subsections are missing. See also --hierarchic.")
+                .action(ArgAction::SetTrue),
+        )
 }