refactor

fix-error/src/lib.rs

@@ -0,0 +1,223 @@
+use std::path::{Path, PathBuf};
+use std::sync::Arc;
+
+use miette::{Diagnostic, NamedSource, SourceSpan};
+use thiserror::Error;
+
+pub type Result<T> = core::result::Result<T, Box<Error>>;
+
+#[derive(Clone, Debug)]
+pub enum SourceType {
+    /// dir
+    Eval(Arc<PathBuf>),
+    /// dir
+    Repl(Arc<PathBuf>),
+    /// file
+    File(Arc<PathBuf>),
+    /// virtual (name, no path)
+    Virtual(Arc<str>),
+}
+
+#[derive(Clone, Debug)]
+pub struct Source {
+    pub ty: SourceType,
+    pub src: Arc<str>,
+}
+
+impl TryFrom<&str> for Source {
+    type Error = Box<Error>;
+    fn try_from(value: &str) -> Result<Self> {
+        Source::new_eval(value.into())
+    }
+}
+
+impl From<Source> for NamedSource<Arc<str>> {
+    fn from(value: Source) -> Self {
+        let name = value.get_name();
+        NamedSource::new(name, value.src.clone())
+    }
+}
+
+impl Source {
+    pub fn new_file(path: PathBuf) -> std::io::Result<Self> {
+        Ok(Source {
+            src: std::fs::read_to_string(&path)?.into(),
+            ty: SourceType::File(Arc::new(path)),
+        })
+    }
+
+    pub fn new_eval(src: String) -> Result<Self> {
+        Ok(Self {
+            ty: std::env::current_dir()
+                .map_err(|err| Error::internal(format!("Failed to get current working dir: {err}")))
+                .map(Arc::new)
+                .map(SourceType::Eval)?,
+            src: src.into(),
+        })
+    }
+
+    pub fn new_repl(src: String) -> Result<Self> {
+        Ok(Self {
+            ty: std::env::current_dir()
+                .map_err(|err| Error::internal(format!("Failed to get current working dir: {err}")))
+                .map(Arc::new)
+                .map(SourceType::Repl)?,
+            src: src.into(),
+        })
+    }
+
+    pub fn new_virtual(name: Arc<str>, src: String) -> Self {
+        Self {
+            ty: SourceType::Virtual(name),
+            src: src.into(),
+        }
+    }
+
+    pub fn get_dir(&self) -> &Path {
+        use SourceType::*;
+        match &self.ty {
+            Eval(dir) | Repl(dir) => dir.as_ref(),
+            File(file) => file
+                .as_path()
+                .parent()
+                .expect("source file must have a parent dir"),
+            Virtual(_) => Path::new("/"),
+        }
+    }
+
+    pub fn get_name(&self) -> String {
+        match &self.ty {
+            SourceType::Eval(_) => "«eval»".into(),
+            SourceType::Repl(_) => "«repl»".into(),
+            SourceType::File(path) => path.as_os_str().to_string_lossy().to_string(),
+            SourceType::Virtual(name) => name.to_string(),
+        }
+    }
+}
+
+#[derive(Error, Debug, Diagnostic)]
+pub enum Error {
+    #[error("Parse error: {message}")]
+    #[diagnostic(code(nix::parse))]
+    ParseError {
+        #[source_code]
+        src: Option<NamedSource<Arc<str>>>,
+        #[label("error occurred here")]
+        span: Option<SourceSpan>,
+        message: String,
+    },
+
+    #[error("Downgrade error: {message}")]
+    #[diagnostic(code(nix::downgrade))]
+    DowngradeError {
+        #[source_code]
+        src: Option<NamedSource<Arc<str>>>,
+        #[label("{message}")]
+        span: Option<SourceSpan>,
+        message: String,
+    },
+
+    #[error("Evaluation error: {message}")]
+    #[diagnostic(code(nix::eval))]
+    EvalError {
+        #[source_code]
+        src: Option<NamedSource<Arc<str>>>,
+        #[label("error occurred here")]
+        span: Option<SourceSpan>,
+        message: String,
+        #[related]
+        stack_trace: Vec<StackFrame>,
+    },
+
+    #[error("Internal error: {message}")]
+    #[diagnostic(code(nix::internal))]
+    InternalError { message: String },
+
+    #[error("{message}")]
+    #[diagnostic(code(nix::catchable))]
+    Catchable { message: String },
+
+    #[error("Unknown error")]
+    #[diagnostic(code(nix::unknown))]
+    Unknown,
+}
+
+impl Error {
+    pub fn parse_error(msg: String) -> Box<Self> {
+        Error::ParseError {
+            src: None,
+            span: None,
+            message: msg,
+        }
+        .into()
+    }
+
+    pub fn downgrade_error(msg: String, src: Source, span: rnix::TextRange) -> Box<Self> {
+        Error::DowngradeError {
+            src: Some(src.into()),
+            span: Some(text_range_to_source_span(span)),
+            message: msg,
+        }
+        .into()
+    }
+
+    pub fn eval_error(msg: impl Into<String>) -> Box<Self> {
+        Error::EvalError {
+            src: None,
+            span: None,
+            message: msg.into(),
+            stack_trace: Vec::new(),
+        }
+        .into()
+    }
+
+    pub fn internal(msg: String) -> Box<Self> {
+        Error::InternalError { message: msg }.into()
+    }
+
+    pub fn catchable(msg: String) -> Box<Self> {
+        Error::Catchable { message: msg }.into()
+    }
+
+    pub fn with_span(mut self: Box<Self>, span: rnix::TextRange) -> Box<Self> {
+        use Error::*;
+        let source_span = Some(text_range_to_source_span(span));
+        let (ParseError { span, .. } | DowngradeError { span, .. } | EvalError { span, .. }) =
+            self.as_mut()
+        else {
+            return self;
+        };
+        *span = source_span;
+        self
+    }
+
+    pub fn with_source(mut self: Box<Self>, source: Source) -> Box<Self> {
+        use Error::*;
+        let new_src = Some(source.into());
+        let (ParseError { src, .. } | DowngradeError { src, .. } | EvalError { src, .. }) =
+            self.as_mut()
+        else {
+            return self;
+        };
+        *src = new_src;
+        self
+    }
+}
+
+pub fn text_range_to_source_span(range: rnix::TextRange) -> SourceSpan {
+    let start = usize::from(range.start());
+    let len = usize::from(range.end()) - start;
+    SourceSpan::new(start.into(), len)
+}
+
+/// Stack frame types from Nix evaluation
+#[derive(Debug, Clone, Error, Diagnostic)]
+#[error("{message}")]
+pub struct StackFrame {
+    #[label]
+    pub span: SourceSpan,
+    #[help]
+    pub message: String,
+    #[source_code]
+    pub src: NamedSource<Arc<str>>,
+}