Add a help message

And in that case do not run the web server.

Also exits if there is a build error.

Closes #211

Author: nrc

src/bin/cargo-src.rs

@@ -26,17 +26,35 @@ fn main() {
         args.next().unwrap();
     }
 
+    let args: Vec<_> = args.collect();
+
+    if args.contains(&"--help".to_owned()) {
+        print_help();
+        return;
+    }
+
     let workspace_root = workspace_root();
 
     let build_args = BuildArgs {
         program: env::var("CARGO").expect("Missing $CARGO var"),
-        args: args.collect(),
+        args,
         workspace_root,
     };
 
     cargo_src::run_server(build_args);
 }
 
+fn print_help() {
+    println!("cargo-src");
+    println!("Browse a program's source code\n");
+    println!("USAGE:");
+    println!("    cargo src [OPTIONS]\n");
+    println!("OPTIONS:");
+    println!("    --help    show this message");
+    println!("    --open    open the cargo-src frontend in your web browser");
+    println!("\nOther options follow `cargo check`, see `cargo check --help` for more.");
+}
+
 fn workspace_root() -> String {
     let output = Command::new("cargo").args(&["metadata", "--format-version", "1"]).output();
     let stdout = String::from_utf8(output.expect("error executing `cargo metadata`").stdout).expect("unexpected output");

src/build/mod.rs

@@ -54,8 +54,11 @@ impl Builder {
     pub fn build(&self) -> Option<i32> {
         let mut cmd = self.init_cmd();
         let status = cmd.status().expect("Running build failed");
-        self.clean_analysis();
-        status.code()
+        let result = status.code();
+        if let Some(0) = result {
+            self.clean_analysis();
+        }
+        result
     }
 
     // Remove any old or duplicate json files.

src/server.rs

@@ -16,7 +16,7 @@ use futures::Future;
 
 use std::fmt;
 use std::path::{Path, PathBuf};
-use std::process::Command;
+use std::process::{self, Command};
 use std::str::FromStr;
 use std::sync::{Arc, Mutex, atomic::{AtomicU32, Ordering}};
 use std::thread;
@@ -74,9 +74,12 @@ impl Server {
         thread::spawn(move || {
             println!("Building...");
             status.start_build();
-            builder.build().unwrap();
+            let code = builder.build().unwrap();
             status.finish_build();
 
+            if code != 0 {
+                process::exit(1);
+            }
             status.start_analysis();
             file_cache.update_analysis();
             status.finish_analysis();