Adds NsReader::prefixes to iterate on all the prefixes currently decl…

…ared

This is useful for some use cases like RDF/XML where prefixes might be interesting to extract

src/name.rs

@@ -617,6 +617,28 @@ impl NamespaceResolver {
             None => ResolveResult::Unbound,
         }
     }
+
+    #[inline]
+    pub fn iter(&self) -> impl Iterator<Item = (PrefixDeclaration, Namespace)> {
+        self.bindings[2..].iter().enumerate().filter_map(|(i, n)| {
+            // We check if the key has not been overriden
+            if self.bindings[i + 3..]
+                .iter()
+                .any(|n2| n.prefix(&self.buffer) == n2.prefix(&self.buffer))
+            {
+                return None; // Overriden
+            }
+            let prefix = if let Some(Prefix(prefix)) = n.prefix(&self.buffer) {
+                PrefixDeclaration::Named(prefix)
+            } else {
+                PrefixDeclaration::Default
+            };
+            let ResolveResult::Bound(namespace) = n.namespace(&self.buffer) else {
+                return None; // We don't return unbound namespaces
+            };
+            Some((prefix, namespace))
+        })
+    }
 }
 
 #[cfg(test)]

src/reader/ns_reader.rs

@@ -12,7 +12,9 @@ use std::path::Path;
 
 use crate::errors::Result;
 use crate::events::Event;
-use crate::name::{LocalName, NamespaceResolver, QName, ResolveResult};
+use crate::name::{
+    LocalName, Namespace, NamespaceResolver, PrefixDeclaration, QName, ResolveResult,
+};
 use crate::reader::{Config, Reader, Span, XmlSource};
 
 /// A low level encoding-agnostic XML event reader that performs namespace resolution.
@@ -48,6 +50,12 @@ impl<R> NsReader<R> {
     pub fn config_mut(&mut self) -> &mut Config {
         self.reader.config_mut()
     }
+
+    /// Returns all the prefixes currently declared except the default xml: and xmlns: namespaces.
+    #[inline]
+    pub fn prefixes(&self) -> impl Iterator<Item = (PrefixDeclaration, Namespace)> {
+        self.ns_resolver.iter()
+    }
 }
 
 /// Private methods

tests/namespaces.rs

@@ -2,7 +2,7 @@ use pretty_assertions::assert_eq;
 use quick_xml::events::attributes::Attribute;
 use quick_xml::events::Event::*;
 use quick_xml::name::ResolveResult::*;
-use quick_xml::name::{Namespace, QName};
+use quick_xml::name::{Namespace, PrefixDeclaration, QName};
 use quick_xml::reader::NsReader;
 use std::borrow::Cow;
 
@@ -28,6 +28,11 @@ fn namespace() {
             e
         ),
     }
+    assert_eq!(
+        r.prefixes().collect::<Vec<_>>(),
+        vec![(PrefixDeclaration::Named(b"myns"), Namespace(b"www1"))]
+    );
+
     // "in namespace!"
     match r.read_resolved_event() {
         Ok((ns, Text(_))) => assert_eq!(ns, Unbound),
@@ -71,6 +76,11 @@ fn default_namespace() {
             e
         ),
     }
+    assert_eq!(
+        r.prefixes().collect::<Vec<_>>(),
+        vec![(PrefixDeclaration::Default, Namespace(b"www1"))]
+    );
+
     // </b>
     match r.read_resolved_event() {
         Ok((ns, End(_))) => assert_eq!(ns, Bound(Namespace(b"www1"))),
@@ -110,6 +120,8 @@ fn default_namespace_reset() {
             e
         ),
     }
+    assert_eq!(r.prefixes().collect::<Vec<_>>(), vec![]);
+
     // </b>
     match r.read_resolved_event() {
         Ok((ns, End(_))) => assert_eq!(ns, Unbound),
@@ -257,6 +269,11 @@ fn default_ns_shadowing_empty() {
             Some((Unbound, &b"att1"[..], Cow::Borrowed(&b"a"[..])))
         );
         assert_eq!(attrs.next(), None);
+
+        assert_eq!(
+            r.prefixes().collect::<Vec<_>>(),
+            vec![(PrefixDeclaration::Default, Namespace(b"urn:example:i")),]
+        );
     }
 
     // </outer>