cleanup errors

src/error.rs

@@ -0,0 +1,58 @@
+use crate::data::*;
+use miette::Diagnostic;
+use thiserror::Error;
+
+#[derive(Debug, Error, Diagnostic)]
+pub enum BspError {
+    #[error("unexpected magic numbers or version")]
+    #[diagnostic(help("Ensure the loaded file is a valve bsp"))]
+    UnexpectedHeader(Header),
+    #[error("bsp lump is out of bounds of the bsp file")]
+    LumpOutOfBounds(LumpEntry),
+    #[error("unexpected length of uncompressed lump, got {got} but expected {expected}")]
+    UnexpectedUncompressedLumpSize { got: u32, expected: u32 },
+    #[error("error while decompressing lump")]
+    LumpDecompressError(lzma_rs::error::Error),
+    #[error("io error while reading data: {0}")]
+    IO(#[from] std::io::Error),
+    #[error(transparent)]
+    String(#[from] StringError),
+}
+
+impl From<binrw::Error> for BspError {
+    fn from(e: binrw::Error) -> Self {
+        use binrw::Error;
+
+        // only a few error types should be generated by our code
+        match e {
+            Error::Io(e) => BspError::IO(e),
+            Error::Custom { err, .. } => {
+                if let Ok(string_error) = err.downcast::<StringError>() {
+                    BspError::String(*string_error)
+                } else {
+                    panic!("unexpected custom error")
+                }
+            }
+            e => panic!("unexpected no variable match: {:?}", e),
+        }
+    }
+}
+
+impl From<lzma_rs::error::Error> for BspError {
+    fn from(e: lzma_rs::error::Error) -> Self {
+        use lzma_rs::error::Error;
+
+        match e {
+            Error::IoError(e) => BspError::IO(e),
+            e => BspError::LumpDecompressError(e),
+        }
+    }
+}
+
+#[derive(Debug, Error, Diagnostic)]
+pub enum StringError {
+    #[error(transparent)]
+    NonUTF8(#[from] std::str::Utf8Error),
+    #[error("String is not null-terminated")]
+    NotNullTerminated,
+}