Detect OpenEXR from its file signature

crates/file-formats/src/lib.rs

@@ -459,6 +459,11 @@ pub fn detect(name: &str, bytes: &[u8]) -> Option<Format> {
     if bytes.starts_with(b"PDN3") {
         return Some(Format::Pdn);
     }
+    // OpenEXR's four-byte magic is its canonical signature (v2, section 2.1.1). Keep it in
+    // the shared registry so file-handle importers can route without relying on a filename.
+    if bytes.starts_with(&[0x76, 0x2f, 0x31, 0x01]) {
+        return Some(Format::OpenExr);
+    }
     if bytes.starts_with(b"gimp xcf ") || gzipped_xcf(name, bytes) {
         return Some(Format::Xcf);
     }
@@ -512,6 +517,9 @@ pub fn detect(name: &str, bytes: &[u8]) -> Option<Format> {
     None
 }
 
+#[cfg(test)]
+mod tests;
+
 /// DesignCraft's older ZIPs predate their leading `mimetype`; they are identified by the
 /// `document.json` member. The directory is bounded before it is indexed and no entry is inflated.
 fn designcraft_zip_has_document(bytes: &[u8]) -> bool {

crates/file-formats/src/tests.rs

@@ -0,0 +1,57 @@
+use super::{Availability, Format};
+
+#[test]
+fn every_registered_family_has_consistent_metadata_and_extension_lookup() {
+    for format in Format::ALL {
+        let extensions = format.extensions();
+        assert_eq!(format.preferred_extension(), extensions.first().copied());
+        assert!(format.mime_type().is_some());
+        let _capabilities = format.capabilities();
+        #[cfg(feature = "raster-codecs")]
+        let _codec = format.raster_codec();
+
+        for extension in extensions {
+            assert_eq!(super::from_extension(extension), Some(format), "{format:?}: {extension}");
+            assert_eq!(super::from_extension(&extension.to_ascii_uppercase()), Some(format), "{format:?}: {extension}");
+        }
+    }
+}
+
+#[test]
+fn known_formats_separate_build_disabled_and_unsupported_operations() {
+    let jpeg = Format::Jpeg.capabilities();
+    assert!(!jpeg.multiple_frames && !jpeg.file_sequence);
+    #[cfg(feature = "raster-codecs")]
+    assert_eq!(jpeg.read, Availability::Available);
+    #[cfg(not(feature = "raster-codecs"))]
+    assert_eq!(jpeg.read, Availability::BuildDisabled);
+
+    assert_eq!(Format::Jxl.capabilities().read, Availability::Unsupported);
+    #[cfg(not(feature = "raster-codecs"))]
+    assert_eq!(Format::Jxl.capabilities().write, Availability::BuildDisabled);
+    assert!(!Format::Psd.capabilities().file_sequence);
+    assert!(Format::Raw.capabilities().file_sequence);
+    assert!(Format::Raw.capabilities().multiple_frames);
+}
+
+#[test]
+fn bounded_probes_prefer_signatures_and_resolve_extensions() {
+    assert_eq!(super::detect("misnamed.png", b"\x76\x2f\x31\x01rest"), Some(Format::OpenExr));
+    assert_eq!(super::detect("misnamed.exr", b"\x89PNG\r\n\x1a\n"), Some(Format::Png));
+    assert_eq!(super::detect("native.psdt", b"8BPS\0\0"), Some(Format::Psd));
+    assert_eq!(super::detect("art.svg", b"<svg xmlns=\"http://www.w3.org/2000/svg\"/>"), Some(Format::Svg));
+    assert_eq!(super::detect("photo.EXR", b""), Some(Format::OpenExr));
+    assert_eq!(super::detect("notes.txt", b""), Some(Format::PlainText));
+    assert_eq!(super::detect("unknown", b""), None);
+}
+
+#[test]
+fn registered_mime_and_preferred_extensions_remain_distinct() {
+    assert_eq!(Format::Svg.mime_type(), Format::Svgz.mime_type());
+    assert_eq!(Format::Svg.preferred_extension(), Some("svg"));
+    assert_eq!(Format::Svgz.preferred_extension(), Some("svgz"));
+    assert_eq!(Format::DesignCraftJson.mime_type(), Some("application/json"));
+    assert_eq!(Format::DesignCraftJson.preferred_extension(), None);
+    assert_eq!(Format::TaggedText.preferred_extension(), None);
+    assert_eq!(super::from_extension("not-a-format"), None);
+}