Tidy up errors

src/colors.rs

@@ -116,7 +116,7 @@ impl TryFrom<u8> for BitDepth {
             4 => Ok(Self::Four),
             8 => Ok(Self::Eight),
             16 => Ok(Self::Sixteen),
-            _ => Err(PngError::new("Unexpected bit depth")),
+            _ => Err(PngError::InvalidData),
         }
     }
 }

src/deflate/deflater.rs

@@ -22,7 +22,7 @@ pub fn inflate(data: &[u8], out_size: usize) -> PngResult<Vec<u8>> {
         .zlib_decompress(data, &mut dest)
         .map_err(|err| match err {
             DecompressionError::BadData => PngError::InvalidData,
-            DecompressionError::InsufficientSpace => PngError::new("inflated data too long"),
+            DecompressionError::InsufficientSpace => PngError::InflatedDataTooLong(out_size),
         })?;
     dest.truncate(len);
     Ok(dest)

src/error.rs

@@ -5,17 +5,17 @@ use crate::colors::{BitDepth, ColorType};
 #[derive(Debug, Clone)]
 #[non_exhaustive]
 pub enum PngError {
-    DeflatedDataTooLong(usize),
-    TimedOut,
-    NotPNG,
-    APNGNotSupported,
     APNGOutOfOrder,
-    InvalidData,
-    TruncatedData,
-    ChunkMissing(&'static str),
-    InvalidDepthForType(BitDepth, ColorType),
-    IncorrectDataLength(usize, usize),
     C2PAMetadataPreventsChanges,
+    ChunkMissing(&'static str),
+    CRCMismatch([u8; 4]),
+    DeflatedDataTooLong(usize),
+    IncorrectDataLength(usize, usize),
+    InflatedDataTooLong(usize),
+    InvalidData,
+    InvalidDepthForType(BitDepth, ColorType),
+    NotPNG,
+    TruncatedData,
     Other(Box<str>),
 }
 
@@ -26,26 +26,30 @@ impl fmt::Display for PngError {
     #[cold]
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
-            PngError::DeflatedDataTooLong(_) => f.write_str("deflated data too long"),
-            PngError::TimedOut => f.write_str("timed out"),
-            PngError::NotPNG => f.write_str("Invalid header detected; Not a PNG file"),
-            PngError::InvalidData => f.write_str("Invalid data found; unable to read PNG file"),
-            PngError::TruncatedData => {
-                f.write_str("Missing data in the file; the file is truncated")
-            }
-            PngError::APNGNotSupported => f.write_str("APNG files are not (yet) supported"),
             PngError::APNGOutOfOrder => f.write_str("APNG chunks are out of order"),
+            PngError::C2PAMetadataPreventsChanges => f.write_str(
+                "The image contains C2PA manifest that would be invalidated by any file changes",
+            ),
             PngError::ChunkMissing(s) => write!(f, "Chunk {s} missing or empty"),
-            PngError::InvalidDepthForType(d, ref c) => {
+            PngError::CRCMismatch(ref c) => write!(
-                write!(f, "Invalid bit depth {d} for color type {c}")
+                f,
-            }
+                "CRC mismatch in {} chunk; May be recoverable by using --fix",
+                String::from_utf8_lossy(c)
+            ),
+            PngError::DeflatedDataTooLong(_) => f.write_str("Deflated data too long"),
             PngError::IncorrectDataLength(l1, l2) => write!(
                 f,
                 "Data length {l1} does not match the expected length {l2}"
             ),
-            PngError::C2PAMetadataPreventsChanges => f.write_str(
+            PngError::InflatedDataTooLong(_) => f.write_str("Inflated data too long"),
-                "The image contains C2PA manifest that would be invalidated by any file changes",
+            PngError::InvalidData => f.write_str("Invalid data found; unable to read PNG file"),
-            ),
+            PngError::InvalidDepthForType(d, ref c) => {
+                write!(f, "Invalid bit depth {d} for color type {c}")
+            }
+            PngError::NotPNG => f.write_str("Invalid header detected; Not a PNG file"),
+            PngError::TruncatedData => {
+                f.write_str("Missing data in the file; the file is truncated")
+            }
             PngError::Other(ref s) => f.write_str(s),
         }
     }

src/headers.rs

@@ -172,10 +172,7 @@ pub fn parse_next_chunk<'a>(
 
     let chunk_bytes = &byte_data[chunk_start..chunk_start + 4 + length as usize];
     if !fix_errors && crc32(chunk_bytes) != crc {
-        return Err(PngError::new(&format!(
+        return Err(PngError::CRCMismatch(chunk_name.try_into().unwrap()));
-            "CRC Mismatch in {} chunk; May be recoverable by using --fix",
-            String::from_utf8_lossy(chunk_name)
-        )));
     }
 
     let name: [u8; 4] = chunk_name.try_into().unwrap();
@@ -208,7 +205,7 @@ pub fn parse_ihdr_chunk(
             },
             4 => ColorType::GrayscaleAlpha,
             6 => ColorType::RGBA,
-            _ => return Err(PngError::new("Unexpected color type in header")),
+            _ => return Err(PngError::InvalidData),
         },
         bit_depth: byte_data[8].try_into()?,
         width: read_be_u32(&byte_data[0..4]),
@@ -216,7 +213,7 @@ pub fn parse_ihdr_chunk(
         interlaced: match interlaced {
             0 => false,
             1 => true,
-            _ => return Err(PngError::new("Unexpected interlacing in header")),
+            _ => return Err(PngError::InvalidData),
         },
     })
 }
@@ -226,7 +223,7 @@ fn palette_to_rgba(
     palette_data: Option<Vec<u8>>,
     trns_data: Option<Vec<u8>>,
 ) -> Result<Vec<RGBA8>, PngError> {
-    let palette_data = palette_data.ok_or_else(|| PngError::new("no palette in indexed image"))?;
+    let palette_data = palette_data.ok_or(PngError::ChunkMissing("PLTE"))?;
     let mut palette: Vec<_> = palette_data
         .chunks_exact(3)
         .map(|color| RGBA8::new(color[0], color[1], color[2], 255))

src/lib.rs

@@ -679,7 +679,7 @@ fn copy_permissions(metadata_input: &Metadata, out_file: &File) -> PngResult<()>
         .set_permissions(metadata_input.permissions())
         .map_err(|err_io| {
             PngError::new(&format!(
-                "unable to set permissions for output file: {err_io}"
+                "Unable to set permissions for output file: {err_io}"
             ))
         })
 }
@@ -695,7 +695,7 @@ fn copy_times(input_path_meta: &Metadata, out_path: &Path) -> PngResult<()> {
     trace!("attempting to set file modification time: {mtime:?}");
     filetime::set_file_mtime(out_path, mtime).map_err(|err_io| {
         PngError::new(&format!(
-            "unable to set file times on {out_path:?}: {err_io}"
+            "Unable to set file times on {out_path:?}: {err_io}"
         ))
     })
 }