fix(exif): Panic when parsing GPSInfo #37

Author: mindeng

src/exif.rs

@@ -254,21 +254,27 @@ mod tests {
 
     #[test_case("exif.heic", "+43.29013+084.22713+1595.950CRSWGS_84/")]
     #[test_case("exif.jpg", "+22.53113+114.02148/")]
+    #[test_case("invalid-gps", "-")]
     fn gps(path: &str, gps_str: &str) {
         let f = open_sample(path).unwrap();
         let iter = parse_exif(f, None)
             .expect("should be Ok")
             .expect("should not be None");
-        let gps_info = iter
-            .parse_gps_info()
-            .expect("should be parsed Ok")
-            .expect("should not be None");
 
-        // let gps_info = iter
-        //     .consume_parse_gps_info()
-        //     .expect("should be parsed Ok")
-        //     .expect("should not be None");
-        assert_eq!(gps_info.format_iso6709(), gps_str);
+        if gps_str == "-" {
+            assert!(iter.parse_gps_info().expect("should be ok").is_none());
+        } else {
+            let gps_info = iter
+                .parse_gps_info()
+                .expect("should be parsed Ok")
+                .expect("should not be None");
+
+            // let gps_info = iter
+            //     .consume_parse_gps_info()
+            //     .expect("should be parsed Ok")
+            //     .expect("should not be None");
+            assert_eq!(gps_info.format_iso6709(), gps_str);
+        }
     }
 
     #[cfg(feature = "async")]

src/exif/exif_iter.rs

@@ -718,16 +718,16 @@ impl IfdIter {
                 }
                 ExifTag::GPSLatitude => {
                     if let Some(v) = entry.as_urational_array() {
-                        gps.latitude = v.iter().collect();
+                        gps.latitude = v.try_into().ok()?;
                     } else if let Some(v) = entry.as_irational_array() {
-                        gps.latitude = v.iter().collect();
+                        gps.latitude = v.try_into().ok()?;
                     }
                 }
                 ExifTag::GPSLongitude => {
                     if let Some(v) = entry.as_urational_array() {
-                        gps.longitude = v.iter().collect();
+                        gps.longitude = v.try_into().ok()?;
                     } else if let Some(v) = entry.as_irational_array() {
-                        gps.longitude = v.iter().collect();
+                        gps.longitude = v.try_into().ok()?;
                     }
                 }
                 ExifTag::GPSAltitude => {

src/exif/gps.rs

@@ -131,28 +131,26 @@ impl FromIterator<URational> for LatLng {
     }
 }
 
-impl<'a> FromIterator<&'a URational> for LatLng {
-    fn from_iter<T: IntoIterator<Item = &'a URational>>(iter: T) -> Self {
-        let mut values = iter.into_iter();
-        Self(
-            *values.next().unwrap(),
-            *values.next().unwrap(),
-            *values.next().unwrap(),
-        )
+impl TryFrom<&Vec<URational>> for LatLng {
+    type Error = crate::Error;
+    fn try_from(value: &Vec<URational>) -> Result<Self, Self::Error> {
+        if value.len() < 3 {
+            Err(crate::Error::ParseFailed("invalid URational data".into()))
+        } else {
+            Ok(Self(value[0], value[1], value[2]))
+        }
     }
 }
-
-impl<'a> FromIterator<&'a IRational> for LatLng {
-    fn from_iter<T: IntoIterator<Item = &'a IRational>>(iter: T) -> Self {
-        let mut values = iter.into_iter();
-        Self(
-            (*values.next().unwrap()).into(),
-            (*values.next().unwrap()).into(),
-            (*values.next().unwrap()).into(),
-        )
+impl TryFrom<&Vec<IRational>> for LatLng {
+    type Error = crate::Error;
+    fn try_from(value: &Vec<IRational>) -> Result<Self, Self::Error> {
+        if value.len() < 3 {
+            Err(crate::Error::ParseFailed("invalid URational data".into()))
+        } else {
+            Ok(Self(value[0].into(), value[1].into(), value[2].into()))
+        }
     }
 }
-
 pub struct InvalidISO6709Coord;
 
 impl FromStr for GPSInfo {