refactor!: simplify error handling by using enum type

Relates to #584

Author: codeart1st

src/error.rs

@@ -1,257 +1,62 @@
-//! This module provides error types and utilities for the `mvt-reader` crate.
+//! This module provides error types for the `mvt-reader` crate.
 //!
-//! # Errors
-//!
-//! The `error` module defines the following error types:
-//!
-//! - `ParserError`: Represents an error that occurs during parsing of a vector tile.
-//! - `GeometryError`: Represents an error related to the geometry of a feature in a vector tile.
-//! - `TagsError`: Represents an error related to the tags of a feature in a vector tile.
-//! - `VersionError`: Represents an error related to the version of a vector tile.
-//! - `DecodeError`: Represents an error indicating a decoding failure during the parsing of a vector tile.
-//!
-//! # Utilities
-//!
-//! The `error` module also provides utility functions and traits for working with errors, such as formatting and error chaining.
-
-/// A structure representing a parser error.
+//! The [`ParserError`] enum represents all possible errors that can occur during
+//! parsing of a vector tile.
+
+/// An error that can occur during parsing of a vector tile.
+///
+/// # Examples
+///
+/// ```
+/// use mvt_reader::error::ParserError;
+///
+/// fn example() -> Result<(), ParserError> {
+///   Err(ParserError::InvalidTags)
+/// }
+/// ```
 #[derive(Debug)]
-pub struct ParserError {
-  source: Box<dyn core::error::Error>,
-}
+pub enum ParserError {
+  /// A protobuf decoding failure.
+  Decode(prost::DecodeError),
 
-impl ParserError {
-  /// Creates a new `ParserError` instance with the provided error source.
-  ///
-  /// # Arguments
-  ///
-  /// * `source` - The underlying error source.
-  ///
-  /// # Examples
-  ///
-  /// ```
-  /// use mvt_reader::error::ParserError;
-  ///
-  /// let source_error = std::io::Error::new(std::io::ErrorKind::Other, "Custom error");
-  /// let parser_error = ParserError::new(source_error);
-  /// ```
-  pub fn new<T: core::error::Error + 'static>(source: T) -> Self {
-    Self {
-      source: Box::new(source),
-    }
-  }
+  /// The layer has an unsupported vector tile version.
+  UnsupportedVersion {
+    layer_name: String,
+    version: u32,
+  },
+
+  /// The tags section of a feature is malformed.
+  InvalidTags,
+
+  /// The geometry section of a feature is malformed.
+  InvalidGeometry,
 }
 
 impl core::fmt::Display for ParserError {
-  /// Formats the error message associated with the `ParserError`.
-  ///
-  /// # Arguments
-  ///
-  /// * `f` - The formatter to write the output to.
-  ///
-  /// # Examples
-  ///
-  /// ```
-  /// use std::error::Error;
-  /// use mvt_reader::error::ParserError;
-  ///
-  /// let source_error = std::io::Error::new(std::io::ErrorKind::Other, "Custom error");
-  /// let parser_error = ParserError::new(source_error);
-  /// println!("{}", parser_error);
-  /// ```
   fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-    self.source.fmt(f)
+    match self {
+      Self::Decode(source) => write!(f, "Decode error: {source}"),
+      Self::UnsupportedVersion { layer_name, version } => write!(
+        f,
+        "Vector tile version not supported for layer `{layer_name}` (found version: {version})"
+      ),
+      Self::InvalidTags => write!(f, "Tags section contains errors"),
+      Self::InvalidGeometry => write!(f, "Geometry section contains errors"),
+    }
   }
 }
 
 impl core::error::Error for ParserError {
-  /// Returns the underlying source of the `ParserError`.
-  ///
-  /// # Examples
-  ///
-  /// ```
-  /// use std::error::Error;
-  /// use mvt_reader::error::ParserError;
-  ///
-  /// let source_error = std::io::Error::new(std::io::ErrorKind::Other, "Custom error");
-  /// let parser_error = ParserError::new(source_error);
-  /// let source = parser_error.source();
-  /// println!("Source: {}", source.unwrap());
-  /// ```
   fn source(&self) -> Option<&(dyn core::error::Error + 'static)> {
-    Some(self.source.as_ref())
-  }
-}
-
-/// A structure representing a version error in a vector tile.
-#[derive(Debug)]
-pub struct VersionError {
-  layer_name: String,
-
-  version: u32,
-}
-
-impl VersionError {
-  /// Creates a new `VersionError` instance with the provided layer name and version.
-  ///
-  /// # Arguments
-  ///
-  /// * `layer_name` - The name of the layer.
-  /// * `version` - The unsupported version number.
-  ///
-  /// # Examples
-  ///
-  /// ```
-  /// use mvt_reader::error::VersionError;
-  ///
-  /// let layer_name = String::from("my_layer");
-  /// let version = 3;
-  /// let version_error = VersionError::new(layer_name, version);
-  /// ```
-  pub fn new(layer_name: String, version: u32) -> Self {
-    Self {
-      layer_name,
-      version,
+    match self {
+      Self::Decode(source) => Some(source),
+      _ => None,
     }
   }
 }
 
-impl core::fmt::Display for VersionError {
-  /// Formats the error message associated with the `VersionError`.
-  ///
-  /// # Arguments
-  ///
-  /// * `f` - The formatter to write the output to.
-  ///
-  /// # Examples
-  ///
-  /// ```
-  /// use mvt_reader::error::VersionError;
-  ///
-  /// let layer_name = String::from("my_layer");
-  /// let version = 3;
-  /// let version_error = VersionError::new(layer_name, version);
-  /// println!("{}", version_error);
-  /// ```
-  fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-    write!(
-      f,
-      "Vector tile version not supported for layer `{}` (found version: {})",
-      self.layer_name, self.version
-    )
-  }
-}
-
-impl core::error::Error for VersionError {}
-
-/// An error indicating that the tags section of a vector tile contains errors.
-#[derive(Debug, Default)]
-pub struct TagsError;
-
-impl TagsError {
-  /// Creates a new `TagsError` instance.
-  ///
-  /// # Examples
-  ///
-  /// ```
-  /// use mvt_reader::error::TagsError;
-  ///
-  /// let tags_error = TagsError::new();
-  /// ```
-  pub fn new() -> Self {
-    Self
+impl From<prost::DecodeError> for ParserError {
+  fn from(error: prost::DecodeError) -> Self {
+    Self::Decode(error)
   }
 }
-
-impl core::fmt::Display for TagsError {
-  /// Formats the error message associated with the `TagsError`.
-  ///
-  /// # Arguments
-  ///
-  /// * `f` - The formatter to write the output to.
-  ///
-  /// # Examples
-  ///
-  /// ```
-  /// use mvt_reader::error::TagsError;
-  ///
-  /// let tags_error = TagsError::new();
-  /// println!("{}", tags_error);
-  /// ```
-  fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-    write!(f, "Tags section contains errors")
-  }
-}
-
-impl core::error::Error for TagsError {}
-
-/// An error indicating that the geometry section of a vector tile contains errors.
-#[derive(Debug, Default)]
-pub struct GeometryError;
-
-impl GeometryError {
-  /// Creates a new `GeometryError` instance.
-  ///
-  /// # Examples
-  ///
-  /// ```
-  /// use mvt_reader::error::GeometryError;
-  ///
-  /// let geometry_error = GeometryError::new();
-  /// ```
-  pub fn new() -> Self {
-    Self
-  }
-}
-
-impl core::fmt::Display for GeometryError {
-  /// Formats the error message associated with the `GeometryError`.
-  ///
-  /// # Arguments
-  ///
-  /// * `f` - The formatter to write the output to.
-  ///
-  /// # Examples
-  ///
-  /// ```
-  /// use mvt_reader::error::GeometryError;
-  ///
-  /// let geometry_error = GeometryError::new();
-  /// println!("{}", geometry_error);
-  /// ```
-  fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-    write!(f, "Geometry section contains errors")
-  }
-}
-
-impl core::error::Error for GeometryError {}
-
-/// An error indicating a decoding failure during the parsing of a vector tile.
-#[derive(Debug)]
-pub struct DecodeError {
-  source: Box<dyn core::error::Error>,
-}
-
-impl DecodeError {
-  /// Creates a new DecodeError instance with the provided decoding error from prost.
-  ///
-  /// # Arguments
-  ///
-  /// * source - The underlying decoding error from prost.
-  pub fn new(source: Box<dyn core::error::Error>) -> Self {
-    Self { source }
-  }
-}
-
-impl core::fmt::Display for DecodeError {
-  /// Formats the error message associated with the `DecodeError`.
-  ///
-  /// # Arguments
-  ///
-  /// * `f` - The formatter to write the output to.
-  fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-    write!(f, "Decode error: {}", self.source)
-  }
-}
-
-impl core::error::Error for DecodeError {}