core: Incorporate code for custom error handling.

src/errors.rs

@@ -0,0 +1,35 @@
+use std::{error, fmt, io};
+
+#[derive(Debug)]
+pub enum DoubleError {
+    EmptyVec,
+    IO(io::Error),
+}
+
+impl fmt::Display for DoubleError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            DoubleError::EmptyVec => write!(f, "please use a vector with at least one element"),
+            // This is a wrapper, so defer to the underlying types' implementation of `fmt`.
+            DoubleError::IO(ref e) => e.fmt(f),
+        }
+    }
+}
+
+impl error::Error for DoubleError {
+    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
+        match *self {
+            DoubleError::EmptyVec => None,
+            // The cause is the underlying implementation error type. Is implicitly
+            // cast to the trait object `&error::Error`. This works because the
+            // underlying type already implements the `Error` trait.
+            DoubleError::IO(ref e) => Some(e),
+        }
+    }
+}
+
+impl From<io::Error> for DoubleError {
+    fn from(err: io::Error) -> DoubleError {
+        DoubleError::IO(err)
+    }
+}

src/lib.rs

@@ -12,6 +12,8 @@ use std::default::Default;
 use chrono::{DateTime, Utc};
 use serde_json::Value;
 
+pub mod errors;
+
 #[derive(Serialize, Deserialize, Clone, Debug)]
 pub struct Page {
     pub slug: String,

src/main.rs

@@ -22,7 +22,7 @@ use chrono::prelude::*;
 use colored::Colorize;
 use docopt::Docopt;
 use env_logger::{Builder, Env};
-use rookeries::{Page, Site};
+use rookeries::{errors, Page, Site};
 use serde_json::Value;
 use std::collections::HashMap;
 use std::ffi::OsString;
@@ -124,7 +124,17 @@ fn main() {
     }
 
     if args.cmd_serve {
-        serve_site(&args);
+        match serve_site(&args) {
+            Ok(_) => {
+                header_message(&format!(
+                    "Serving project at local port {}",
+                    &args.flag_port.to_string().cyan()
+                ));
+            }
+            Err(e) => {
+                fatal_error(e.into(), "Server failed!");
+            }
+        };
     }
 
     if args.cmd_build {
@@ -160,7 +170,7 @@ fn fatal_condition(message: &str) -> ! {
     std::process::exit(2);
 }
 
-fn serve_site(args: &Args) {
+fn serve_site(args: &Args) -> Result<(), errors::DoubleError> {
     // TODO: Add an option to open up a browser window using xdg-open.
     // TODO: Create a file watcher to check for changes to the source files?
     let project_directory = get_project_directory(&args);
@@ -180,28 +190,28 @@ fn serve_site(args: &Args) {
         x => x,
     };
 
-    header_message(&format!(
-        "Serving project at local port {}",
-        port.to_string().cyan()
-    ));
-
     HttpServer::new(move || {
         App::new()
             .service(actix_files::Files::new("/", build_directory.clone()).index_file("index.html"))
             .wrap(Logger::default())
     })
     .bind(format!("127.0.0.1:{}", port))
-    .unwrap_or_else(|err| {
-        let error_message = format!(
-            "The server could not to bind to port \"{}\".  Try using a different port.",
-            port.to_string().red()
-        );
-        fatal_error(err.into(), &error_message);
-    })
-    .run()
-    .unwrap_or_else(|err| {
-        fatal_error(err.into(), "The server could not start!");
-    });
+    .and_then(|res| {
+        header_message(&format!(
+            "Serving project at local port {}",
+            port.to_string().cyan()
+        ));
+        Ok(res)
+    })?
+    //    .unwrap_or_else(|err| {
+    //        let error_message = format!(
+    //            "The server could not to bind to port \"{}\".  Try using a different port.",
+    //            port.to_string().red()
+    //        );
+    //        fatal_error(err.into(), &error_message);
+    //    })
+    .run()?;
+    Ok(())
 }
 
 fn build_site(args: &Args) {