Implement retrieving XMP metadata for Webp

Author: 1c3t3a

src/codecs/webp/decoder.rs

@@ -84,6 +84,12 @@ impl<R: BufRead + Seek> ImageDecoder for WebPDecoder<R> {
         Ok(exif)
     }
 
+    fn xmp_metadata(&mut self) -> ImageResult<Option<Vec<u8>>> {
+        self.inner
+            .xmp_metadata()
+            .map_err(ImageError::from_webp_decode)
+    }
+
     fn orientation(&mut self) -> ImageResult<Orientation> {
         // `exif_metadata` caches the orientation, so call it if `orientation` hasn't been set yet.
         if self.orientation.is_none() {

tests/images/webp/lossless_images/simple_xmp.webp

@@ -2,23 +2,47 @@ use std::fs;
 use std::path::PathBuf;
 use std::str::FromStr;
 
-use image::{codecs::png::PngDecoder, ImageDecoder};
+use image::ImageDecoder;
+
+#[cfg(feature = "png")]
+use image::codecs::png::PngDecoder;
+#[cfg(feature = "webp")]
+use image::codecs::webp::WebPDecoder;
 
 extern crate glob;
 extern crate image;
 
 const XMP_PNG_PATH: &str = "tests/images/png/transparency/tp1n3p08_xmp.png";
-const EXPECTED_METADATA: &str = "<?xpacket begin='\u{feff}' id='W5M0MpCehiHzreSzNTczkc9d'?>\n<x:xmpmeta xmlns:x='adobe:ns:meta/' x:xmptk='Image::ExifTool 13.25'>\n<rdf:RDF xmlns:rdf='http://www.w3.org/1999/02/22-rdf-syntax-ns#'>\n\n <rdf:Description rdf:about=''\n  xmlns:dc='http://purl.org/dc/elements/1.1/'>\n  <dc:subject>\n   <rdf:Bag>\n    <rdf:li>sunset, mountains, nature</rdf:li>\n   </rdf:Bag>\n  </dc:subject>\n </rdf:Description>\n</rdf:RDF>\n</x:xmpmeta>\n<?xpacket end='r'?>";
+const EXPECTED_PNG_METADATA: &str = "<?xpacket begin='\u{feff}' id='W5M0MpCehiHzreSzNTczkc9d'?>\n<x:xmpmeta xmlns:x='adobe:ns:meta/' x:xmptk='Image::ExifTool 13.25'>\n<rdf:RDF xmlns:rdf='http://www.w3.org/1999/02/22-rdf-syntax-ns#'>\n\n <rdf:Description rdf:about=''\n  xmlns:dc='http://purl.org/dc/elements/1.1/'>\n  <dc:subject>\n   <rdf:Bag>\n    <rdf:li>sunset, mountains, nature</rdf:li>\n   </rdf:Bag>\n  </dc:subject>\n </rdf:Description>\n</rdf:RDF>\n</x:xmpmeta>\n<?xpacket end='r'?>";
+
+const XMP_WEBP_PATH: &str = "tests/images/webp/lossless_images/simple_xmp.webp";
+const EXPECTED_WEBP_METADATA: &str = "<?xpacket begin='\u{feff}' id='W5M0MpCehiHzreSzNTczkc9d'?>\n<x:xmpmeta xmlns:x='adobe:ns:meta/' x:xmptk='Image::ExifTool 13.25'>\n<rdf:RDF xmlns:rdf='http://www.w3.org/1999/02/22-rdf-syntax-ns#'>\n\n <rdf:Description rdf:about=''\n  xmlns:dc='http://purl.org/dc/elements/1.1/'>\n  <dc:subject>\n   <rdf:Bag>\n    <rdf:li>sunset, mountains, nature</rdf:li>\n   </rdf:Bag>\n  </dc:subject>\n </rdf:Description>\n</rdf:RDF>\n</x:xmpmeta>\n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n<?xpacket end='w'?>";
 
 #[test]
+#[cfg(feature = "png")]
 fn test_read_xmp_png() -> Result<(), image::ImageError> {
     let img_path = PathBuf::from_str(XMP_PNG_PATH).unwrap();
 
     let data = fs::read(img_path)?;
     let mut png_decoder = PngDecoder::new(std::io::Cursor::new(data))?;
     let metadata = png_decoder.xmp_metadata()?;
     assert!(metadata.is_some());
-    assert_eq!(EXPECTED_METADATA.as_bytes(), metadata.unwrap());
+    assert_eq!(EXPECTED_PNG_METADATA.as_bytes(), metadata.unwrap());
+
+    Ok(())
+}
+
+#[test]
+#[cfg(feature = "webp")]
+fn test_read_xmp_webp() -> Result<(), image::ImageError> {
+    let img_path = PathBuf::from_str(XMP_WEBP_PATH).unwrap();
+
+    let data = fs::read(img_path)?;
+    let mut webp_decoder = WebPDecoder::new(std::io::Cursor::new(data))?;
+    let metadata = webp_decoder.xmp_metadata()?;
+
+    assert!(metadata.is_some());
+    assert_eq!(EXPECTED_WEBP_METADATA.as_bytes(), metadata.unwrap());
 
     Ok(())
 }