Support shebangs

js/main.ts

@@ -86,7 +86,6 @@ export default function denoMain() {
   const cwd = startResMsg.cwd();
   log("cwd", cwd);
 
-  // TODO handle shebang.
   for (let i = 1; i < startResMsg.argvLength(); i++) {
     args.push(startResMsg.argv(i));
   }

src/deno_dir.rs

@@ -1,6 +1,6 @@
 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
 use dirs;
-use errors::DenoError;
+use errors;
 use errors::DenoResult;
 use errors::ErrorKind;
 use fs as deno_fs;
@@ -208,7 +208,7 @@ impl DenoDir {
     self: &Self,
     module_specifier: &str,
     containing_file: &str,
-  ) -> Result<CodeFetchOutput, DenoError> {
+  ) -> Result<CodeFetchOutput, errors::DenoError> {
     debug!(
       "code_fetch. module_specifier {} containing_file {}",
       module_specifier, containing_file
@@ -218,24 +218,26 @@ impl DenoDir {
       self.resolve_module(module_specifier, containing_file)?;
 
     let result = self.get_source_code(module_name.as_str(), filename.as_str());
-    let out = match result {
+    let mut out = match result {
+      Ok(out) => out,
       Err(err) => {
         if err.kind() == ErrorKind::NotFound {
           // For NotFound, change the message to something better.
-          return Err(DenoError::from(std::io::Error::new(
-            std::io::ErrorKind::NotFound,
+          return Err(errors::new(
+            ErrorKind::NotFound,
             format!(
               "Cannot resolve module \"{}\" from \"{}\"",
               module_specifier, containing_file
             ),
-          )));
+          ));
         } else {
           return Err(err);
         }
       }
-      Ok(out) => out,
     };
 
+    out.source_code = filter_shebang(out.source_code);
+
     let result =
       self.load_cache(out.filename.as_str(), out.source_code.as_str());
     match result {
@@ -941,3 +943,28 @@ fn test_map_content_type() {
     msg::MediaType::Unknown
   );
 }
+
+fn filter_shebang(code: String) -> String {
+  if !code.starts_with("#!") {
+    return code;
+  }
+  match code.find('\n') {
+    None => {
+      return String::from("");
+    }
+    Some(i) => {
+      let (_, rest) = code.split_at(i);
+      return String::from(rest);
+    }
+  }
+}
+
+#[test]
+fn test_filter_shebang() {
+  assert_eq!(filter_shebang("".to_string()), "");
+  assert_eq!(filter_shebang("#".to_string()), "#");
+  assert_eq!(filter_shebang("#!".to_string()), "");
+  assert_eq!(filter_shebang("#!\n\n".to_string()), "\n\n");
+  let code = "#!/usr/bin/env deno\nconsole.log('hello');\n".to_string();
+  assert_eq!(filter_shebang(code), "\nconsole.log('hello');\n");
+}