Accept missing static_files dir

src/build.rs

@@ -1,5 +1,6 @@
 use std::env;
 use std::fs::{read_dir, File};
+use std::io::ErrorKind::NotFound;
 use std::io::Read;
 use std::io::Write;
 use std::path::{Path, PathBuf};
@@ -20,24 +21,34 @@ pub fn create_static_output_files(source_dir: &str) {
   let out_dir = env::var("OUT_DIR").unwrap();
   let dest_path = Path::new(&out_dir).join("static_files.rs");
   let mut f = File::create(&dest_path).unwrap();
-  for maybe_dir_entry in read_dir(source_dir).unwrap() {
-    let file_path = maybe_dir_entry.unwrap().path();
-    let mut buffer = String::new();
-    File::open(file_path.clone())
-      .unwrap()
-      .read_to_string(&mut buffer)
-      .unwrap();
-    let fence = buffer.chars().filter(|c| *c == '#').collect::<String>() + "#";
-    f.write_all(
-      format!(
-        "pub const {}: &str = r{1}\"{2}\"{1};\n",
-        get_const_name(&file_path),
-        fence,
-        buffer
-      )
-      .as_bytes(),
-    )
-    .unwrap();
+  match read_dir(source_dir) {
+    Ok(dir_content) => {
+      for maybe_dir_entry in dir_content {
+        let file_path = maybe_dir_entry.unwrap().path();
+        let mut buffer = String::new();
+        File::open(file_path.clone())
+          .unwrap()
+          .read_to_string(&mut buffer)
+          .unwrap();
+        let fence = buffer.chars().filter(|c| *c == '#').collect::<String>() + "#";
+        f.write_all(
+          format!(
+            "pub const {}: &str = r{1}\"{2}\"{1};\n",
+            get_const_name(&file_path),
+            fence,
+            buffer
+          )
+          .as_bytes(),
+        )
+        .unwrap();
+      }
+    }
+    Err(err) => {
+      if err.kind() == NotFound {
+      } else {
+        Err(err).unwrap()
+      }
+    }
   }
 }