Migrate from String to properly typed TiffUnsupportedError

src/error.rs

@@ -3,6 +3,8 @@ use std::fmt;
 use std::io;
 
 use decoder::ifd::{Tag, Value};
+use decoder::{PhotometricInterpretation, CompressionMethod, PlanarConfiguration};
+use ColorType;
 
 /// Tiff error kinds.
 #[derive(Debug)]
@@ -11,13 +13,13 @@ pub enum TiffError {
     FormatError(TiffFormatError),
 
     /// The Decoder does not support this image format
-    UnsupportedError(String),
+    UnsupportedError(TiffUnsupportedError),
 
     /// An I/O Error occurred while decoding the image
     IoError(io::Error),
 }
 
-#[derive(Debug, Clone, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum TiffFormatError {
     TiffSignatureNotFound,
     TiffSignatureInvalid,
@@ -41,6 +43,40 @@ impl fmt::Display for TiffFormatError {
     }
 }
 
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub enum TiffUnsupportedError {
+    HorizontalPredictor(ColorType),
+    InterpretationWithBits(PhotometricInterpretation, Vec<u8>),
+    UnknownInterpretation,
+    UnknownCompressionMethod,
+    UnsupportedCompressionMethod(CompressionMethod),
+    UnsupportedSampleDepth(u8),
+    UnsupportedColorType(ColorType),
+    UnsupportedBitsPerChannel(u8),
+    UnsupportedPlanarConfig(Option<PlanarConfiguration>),
+    UnsupportedDataType,
+}
+
+impl fmt::Display for TiffUnsupportedError {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        use self::TiffUnsupportedError::*;
+        match *self {
+            HorizontalPredictor(color_type) => write!(fmt, "Horizontal predictor for {:?} is unsupported.", color_type),
+            InterpretationWithBits(ref photometric_interpretation, ref bits_per_sample) => {
+                write!(fmt, "{:?} with {:?} bits per sample is unsupported", photometric_interpretation, bits_per_sample)
+            },
+            UnknownInterpretation => write!(fmt, "The image is using an unknown photometric interpretation."),
+            UnknownCompressionMethod => write!(fmt, "Unknown compression method."),
+            UnsupportedCompressionMethod(method) => write!(fmt, "Compression method {:?} is unsupported", method),
+            UnsupportedSampleDepth(samples) => write!(fmt, "{} samples per pixel is supported.", samples),
+            UnsupportedColorType(color_type) => write!(fmt, "Color type {:?} is unsupported", color_type),
+            UnsupportedBitsPerChannel(bits) => write!(fmt, "{} bits per channel not supported", bits),
+            UnsupportedPlanarConfig(config) => write!(fmt, "Unsupported planar configuration “{:?}”.", config),
+            UnsupportedDataType => write!(fmt, "Unsupported data type."),
+        }
+    }
+}
+
 impl fmt::Display for TiffError {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
         match *self {