From 2b333ce579e2ace07d270639a0573b162c7c4f15 Mon Sep 17 00:00:00 2001
From: Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
Date: Wed, 24 Jul 2024 17:47:35 +0200
Subject: [PATCH] xso: Add an EmptyAsError text codec

As its name implies, this codec emits an error when the parsed string is
empty.
---
 xso/src/text.rs | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/xso/src/text.rs b/xso/src/text.rs
index 70ef9131..988a7d60 100644
--- a/xso/src/text.rs
+++ b/xso/src/text.rs
@@ -171,6 +171,27 @@ impl TextCodec<Option<String>> for EmptyAsNone {
     }
 }
 
+/// Text codec which returns None instead of the empty string.
+pub struct EmptyAsError;
+
+impl TextCodec<String> for EmptyAsError {
+    fn decode(s: String) -> Result<String, Error> {
+        if s.is_empty() {
+            Err(Error::Other("Empty text node."))
+        } else {
+            Ok(s)
+        }
+    }
+
+    fn encode(value: &String) -> Result<Option<Cow<'_, str>>, Error> {
+        if value.is_empty() {
+            Err(Error::Other("Empty text node."))
+        } else {
+            Ok(Some(Cow::Borrowed(value.as_str())))
+        }
+    }
+}
+
 /// Trait for preprocessing text data from XML.
 ///
 /// This may be used by codecs to allow to customize some of their behaviour.