added c-main dependency

Cargo.lock

@@ -30,6 +30,15 @@ version = "1.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
+[[package]]
+name = "c-main"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "797bbff8bd2bcddb7f0ee638b55398686adac15174689a86da5ffc0f51219f75"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "cexpr"
 version = "0.6.0"
@@ -205,6 +214,7 @@ dependencies = [
 name = "tomcat"
 version = "0.0.1"
 dependencies = [
+ "c-main",
  "toml",
  "yacexits",
 ]

Cargo.toml

@@ -6,5 +6,6 @@ license = "AGPL-3.0-or-later"
 authors = [ "Emma Tebibyte <emma@tebibyte.media>" ]
 
 [dependencies]
+c-main = "1.0.1"
 toml = "0.5.9"
 yacexits = "0.1.2"

src/main.rs

@@ -16,18 +16,18 @@
  * along with this program. If not, see https://www.gnu.org/licenses/.
  */
 
+#![no_main]
+
 use std::{
-  env,
   fs::File,
-  io::{
-    Read,
-    stdin,
-  },
+  io::Read,
   iter::Peekable,
+  os::fd::{ FromRawFd },
   path::Path,
   str::FromStr,
 };
 
+use c_main::Args;
 use toml::Value;
 use yacexits::*;
 
@@ -48,21 +48,15 @@ fn parse_toml(
 
     match value {
       Value::Table(table) => {
-        match tabkey.peek() {
-          Some(_) => {
+        if tabkey.peek().is_some() {
             root = toml::Value::Table(table.to_owned());
             continue;
-          },
-          None => {}, // out.push_str(table.as_str()),
         };
       },
       _ => {
-        match tabkey.peek() {
-          Some(_) => {
-            return Err((format!("{}: Not a table.", item), EX_DATAERR));
-          },
-          None => {},
-        };
+        if tabkey.peek().is_some() {
+          return Err((format!("{}: Not a table.", item), EX_DATAERR));
+        }
       },
     };
 
@@ -105,54 +99,46 @@ fn parse_toml(
   Ok(out)
 }
 
-fn main() {
-  let argv: Vec<String> = env::args().collect();
+#[no_mangle]
+fn rust_main(args: Args) {
+  let argv: Vec<&str> = args.into_iter().collect();
   let usage_info = format!("Usage: {} [table.]key[[index]] [file...]", argv[0]);
 
   if argv.len() <= 1 {
     eprintln!("{}", usage_info);
-    exit(64); // sysexits(3) EX_USAGE
+    exit(EX_USAGE);
   }
-  
-  let input = match argv.get(2) {
-    Some(val) => val,
-    None => {
-      eprintln!("{}", usage_info);
-      exit(EX_USAGE);
-    },
-  };
+
+  let input = argv.get(2).unwrap_or(&"");
+
   let mut content = Vec::new();
   
-  let file = Path::new(&input);
-
-  if input == &"-" {
-    match stdin().lock().read_to_end(&mut content) {
-      Ok(_) => {},
-      Err(_) => {
-        eprintln!("{}: Could not read from standard input.", argv[0]);
-        exit(EX_OSERR);
-      },
-    };
-  } else {
-    match File::open(file).unwrap().read_to_end(&mut content) {
-      Ok(_) => {},
-      Err(_) => {
-        eprintln!("{}: {:?}: No such file or directory.", argv[0], file);
+  match input.to_owned() {
+    "-" | "" => unsafe { File::from_raw_fd(0) },
+    _ => {
+      File::open(Path::new(&input)).unwrap_or_else(|_| {
+        eprintln!(
+          "{}: {}: No such file or directory.",
+          argv[0],
+          &input
+        );
         exit(EX_UNAVAILABLE);
-      },
-    };
-  }
+      })
+    },
+  }.read_to_end(&mut content)
+    .unwrap_or_else(|_| {
+      eprintln!("{}: Could not read input.", argv[0]);
+      exit(EX_OSERR);
+    });
+
 
   let mut tabkey: Vec<&str> = argv[1].split(".").collect();
   let mut indexvec = Vec::new();
   let mut index: Option<usize> = None;
 
-  match tabkey.iter().skip(1).peekable().peek() {
-    Some(_) => {
+  if tabkey.iter().skip(1).peekable().peek().is_some() {
       indexvec = tabkey[1].split(&['[', ']'][..]).collect();
       tabkey[1] = indexvec.remove(0);
-    },
-    None => {},
   };
 
   if ! indexvec.is_empty() {
@@ -166,13 +152,16 @@ fn main() {
     };
   }
 
-  let root = match String::from_utf8(content).unwrap().parse::<Value>() {
-    Ok(toml) => toml,
-    Err(_) => {
+  let root = String::from_utf8(content)
+    .unwrap_or_else(|_| {
+      eprintln!("{}: Input is not valid UTF-8.", argv[0]);
+      exit(EX_DATAERR);
+    })
+    .parse::<Value>()
+    .unwrap_or_else(|_| {
       eprintln!("{}: Unable to parse TOML.", argv[0]);
       exit(EX_DATAERR);
-    },
-  };
+    });
 
   let valiter = tabkey.iter().peekable();
   println!(