impove error handling

src/error.rs

@@ -1,36 +1,72 @@
-use std::{io::{Error as IOError, ErrorKind}, path::StripPrefixError};
+use std::{
+    fmt::Display,
+    io::{Error as IOError, ErrorKind},
+    path::StripPrefixError,
+};
 
 use glob::PatternError;
 #[derive(Debug)]
-pub struct Error {
+pub struct Error<'a> {
     message: String,
+    source: Option<&'a dyn std::error::Error>,
 }
 
-impl From<String> for Error {
-    fn from(value: String) -> Self {
-        Self { message: value }
+impl<'a> Display for Error<'a> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", &self.message)?;
+
+        if let Some(source) = self.source {
+            write!(f, " ({})", &source)?;
+        }
+
+        Ok(())
     }
 }
 
-impl From<PatternError> for Error {
+impl<'a> std::error::Error for Error<'a> {
+    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+        self.source
+    }
+}
+
+impl<'a> From<String> for Error<'a> {
+    fn from(value: String) -> Self {
+        Self {
+            message: value,
+            source: None,
+        }
+    }
+}
+
+impl<'a> From<PatternError> for Error<'a> {
     fn from(value: PatternError) -> Self {
         Self {
             message: value.to_string(),
+            source: Some(&value),
         }
     }
 }
 
-impl From<StripPrefixError> for Error {
+impl<'a> From<StripPrefixError> for Error<'a> {
     fn from(value: StripPrefixError) -> Self {
         Self {
             message: value.to_string(),
+            source: Some(&value),
         }
     }
 }
 
-impl From<Error> for IOError {
+impl<'a> From<Error<'a>> for IOError {
     fn from(value: Error) -> Self {
         IOError::new(ErrorKind::Other, value.message)
     }
 }
 
+impl<'a> From<&dyn std::error::Error> for Error<'a> {
+    fn from(value: &dyn std::error::Error) -> Self {
+        Self {
+            message: value.to_string(),
+            source: Some(&value),
+        }
+    }
+}

src/main.rs

@@ -1,17 +1,19 @@
-pub mod error;
-pub mod context;
 pub mod config;
+pub mod context;
+pub mod error;
 mod file_path;
 
-use clap::Parser as Clap;
 use config::Config;
 use context::Context;
+use error::Error;
 use file_path::FilePath;
-use crate::error::Error;
+
 use roxy_markdown_parser::MarkdownParser;
 use roxy_markdown_tera_rewriter::{MarkdownTeraPreformatter, MarkdownTeraRewriter};
 use roxy_syntect::SyntectParser;
 use roxy_tera_parser::{TeraParser, TeraParserOptions};
+
+use clap::Parser as Clap;
 use std::{
     fs::{self, File},
     io::{BufReader, Read},
@@ -48,71 +50,94 @@ fn get_files<P: AsRef<Path> + std::fmt::Debug>(path: &P) -> Result<Vec<PathBuf>,
     Ok(files)
 }
 
-fn main() -> Result<(), Error> {
-    let opts = Options::parse();
-
-    let file_path = FilePath::new(&opts.input, &opts.output);
-
-    let config_path = file_path.input.with_file_name("config.toml");
-    let config = fs::read_to_string(&config_path).map_or_else(
+fn load_config(path: &Path) -> Config {
+    fs::read_to_string(path).map_or_else(
         |_| Config::default(),
         |f| {
             toml::from_str::<Config>(f.as_str())
                 .unwrap()
                 .merge(Config::default())
         },
-    );
+    )
+}
+
+fn context_from_meta_files<'a, T: AsRef<Path>>(
+    files: &Vec<&PathBuf>,
+    file_path: &'a FilePath<T>,
+) -> Result<Context, Error<'a>> {
+    let mut context = Context::new();
+
+    for path in files {
+        let mut buf = Vec::new();
+
+        let mut file = File::open(path).map(BufReader::new)?;
+        file.read_to_end(&mut buf)?;
+        let mut str = String::from_utf8(buf)?;
+        let toml: Table = toml::from_str(&mut str)?;
+
+        context.insert(&file_path.strip_root(path)?, &tera::to_value(toml)?);
+    }
+
+    Ok(context)
+}
+
+fn create_parser<'a, T: AsRef<Path>>(
+    file: &Path,
+    file_path: &FilePath<T>,
+    context: &'a Context,
+    theme: &str,
+) -> Result<Parser<'a>, Error<'a>> {
+    let mut parser = Parser::new();
+    let mut preformatter = MarkdownTeraPreformatter::new();
+    parser.push(&mut preformatter);
+
+    let mut syntect = SyntectParser::new(theme);
+    parser.push(&mut syntect);
+
+    let mut md = MarkdownParser::new();
+    parser.push(&mut md);
+
+    let mut rewriter = MarkdownTeraRewriter::new();
+    parser.push(&mut rewriter);
+
+    let file_name = file.with_extension("html");
+    let output_path = file_path.to_output(&file_name)?;
+
+    if let Ok(path) = &file_path.strip_root(&file_name) {
+        if let Some(current_context) = context.get(path) {
+            context.insert(&"this", &current_context.clone());
+        }
+    }
+
+    let mut tera = tera::Tera::default();
+    let mut html = TeraParser::new(&mut tera, TeraParserOptions::default());
+    html.add_context(context.to_inner());
+    Ok(parser)
+}
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let opts = Options::parse();
+
+    let file_path = FilePath::new(&opts.input, &opts.output);
+
+    let config_path = file_path.input.with_file_name("config.toml");
+    let config = load_config(&config_path);
 
     let files = get_files(&file_path.input)?;
     let (meta, files): (Vec<&PathBuf>, Vec<&PathBuf>) =
         files.iter().partition(|f| f.extension().unwrap() == "toml");
 
-    let mut context = Context::new();
-
-    for path in meta {
-        let mut buf = Vec::new();
-
-        let mut file = File::open(path).map(BufReader::new).unwrap();
-        file.read_to_end(&mut buf).unwrap();
-        let mut str = String::from_utf8(buf).unwrap();
-        let toml: Table = toml::from_str(&mut str).unwrap();
-
-        context.insert(
-            &file_path.strip_root(path).unwrap(),
-            &tera::to_value(toml).unwrap(),
-        );
-    }
+    let mut context = context_from_meta_files(&meta, &file_path)?;
 
     let theme = config.theme.unwrap_or(DEFAULT_THEME.to_string());
     for file in files {
-        let mut parser = Parser::new();
-        let mut preformatter = MarkdownTeraPreformatter::new();
-        parser.push(&mut preformatter);
-
-        let mut syntect = SyntectParser::new(&theme.as_str());
-        parser.push(&mut syntect);
-
-        let mut md = MarkdownParser::new();
-        parser.push(&mut md);
-
-        let mut rewriter = MarkdownTeraRewriter::new();
-        parser.push(&mut rewriter);
+        let mut parser = create_parser(file, &file_path, &context, &theme)?;
 
         let file_name = file.with_extension("html");
         let output_path = file_path.to_output(&file_name)?;
 
-        if let Ok(path) = &file_path.strip_root(&file_name) {
-            if let Some(current_context) = context.get(path) {
-                context.insert(&"this", &current_context.clone());
-            }
-        }
-
-        let mut tera = tera::Tera::default();
-        let mut html = TeraParser::new(&mut tera, TeraParserOptions::default());
-        html.add_context(context.to_inner());
-        parser.push(&mut html);
-
         Roxy::process_file(&file, &output_path, &mut parser).unwrap();
     }
+
     Ok(())
 }