From 04579bcde40b5b50bf8501eec3377253cfbe34f3 Mon Sep 17 00:00:00 2001
From: Astro <astro@spaceboyz.net>
Date: Fri, 25 Mar 2022 01:37:56 +0100
Subject: [PATCH] minidom: allow tokenizer to be used with a preexisting
 BytesMut

---
 minidom/src/lib.rs           |  2 +-
 minidom/src/tokenizer.rs     | 62 +++++++++++++++++++++---------------
 tokio-xmpp/src/xmpp_codec.rs | 17 ++--------
 3 files changed, 39 insertions(+), 42 deletions(-)

diff --git a/minidom/src/lib.rs b/minidom/src/lib.rs
index beea39a..5717ada 100644
--- a/minidom/src/lib.rs
+++ b/minidom/src/lib.rs
@@ -96,4 +96,4 @@ pub use error::{Error, Result};
 pub use namespaces::NSChoice;
 pub use node::Node;
 pub use token::Token;
-pub use tokenizer::{Tokenizer, TokenizerError};
+pub use tokenizer::{Tokenizer, TokenizerError, tokenize};
diff --git a/minidom/src/tokenizer.rs b/minidom/src/tokenizer.rs
index e0f13d1..7f3be48 100644
--- a/minidom/src/tokenizer.rs
+++ b/minidom/src/tokenizer.rs
@@ -33,34 +33,44 @@ impl Tokenizer {
 
     /// Parse the next document fragment
     pub fn pull(&mut self) -> Result<Option<Token>, Error> {
-        /// cannot return an error with location info that points to
-        /// our buffer that we still want to mutate
-        fn with_input_to_owned(e: nom::error::Error<&[u8]>) -> TokenizerError {
-            nom::error::Error {
-                input: std::str::from_utf8(e.input)
-                    .unwrap_or("invalud UTF-8")
-                    .to_owned(),
-                code: e.code,
-            }
+        tokenize(&mut self.buffer)
+    }
+}
+
+/// Parse the next document fragment
+///
+/// By using this function directly instead of constructing a
+/// Tokenizer, you can work with a preexisting BytesMut instance that
+/// has been passed by tokio_util::codec::Decoder::decode() for
+/// example.
+pub fn tokenize(buffer: &mut BytesMut) -> Result<Option<Token>, Error> {
+    /// cannot return an error with location info that points to
+    /// our buffer that we still want to mutate
+    fn with_input_to_owned(e: nom::error::Error<&[u8]>) -> TokenizerError {
+        nom::error::Error {
+            input: std::str::from_utf8(e.input)
+                .unwrap_or("invalud UTF-8")
+                .to_owned(),
+            code: e.code,
         }
-        
-        let result: Option<(usize, Token)> = { match Token::parse(&self.buffer) {
-            Ok((s, token)) =>
-                Some((s.len(), token)),
-            Result::Err(nom::Err::Incomplete(_)) =>
-                None,
-            Result::Err(nom::Err::Error(e)) =>
-                return Err(with_input_to_owned(e).into()),
-            Result::Err(nom::Err::Failure(e)) =>
-                return Err(with_input_to_owned(e).into()),
-        } };
-        match result {
-           Some((s_len, token)) => {
-               let _ = self.buffer.split_to(self.buffer.len() - s_len);
-               Ok(Some(token))
-           }
-            None => Ok(None)
+    }
+
+    let result: Option<(usize, Token)> = { match Token::parse(&buffer) {
+        Ok((s, token)) =>
+            Some((s.len(), token)),
+        Result::Err(nom::Err::Incomplete(_)) =>
+            None,
+        Result::Err(nom::Err::Error(e)) =>
+            return Err(with_input_to_owned(e).into()),
+        Result::Err(nom::Err::Failure(e)) =>
+            return Err(with_input_to_owned(e).into()),
+    } };
+    match result {
+        Some((s_len, token)) => {
+            let _ = buffer.split_to(buffer.len() - s_len);
+            Ok(Some(token))
         }
+        None => Ok(None)
     }
 }
 
diff --git a/tokio-xmpp/src/xmpp_codec.rs b/tokio-xmpp/src/xmpp_codec.rs
index fcd6b08..b990897 100644
--- a/tokio-xmpp/src/xmpp_codec.rs
+++ b/tokio-xmpp/src/xmpp_codec.rs
@@ -9,7 +9,7 @@ use std::fmt::Write;
 use std::io;
 use tokio_util::codec::{Decoder, Encoder};
 use xmpp_parsers::Element;
-use minidom::{Tokenizer, tree_builder::TreeBuilder};
+use minidom::{tokenize, tree_builder::TreeBuilder};
 use crate::Error;
 
 /// Anything that can be sent or received on an XMPP/XML stream
@@ -30,18 +30,15 @@ pub struct XMPPCodec {
     /// Outgoing
     ns: Option<String>,
     /// Incoming
-    tokenizer: Tokenizer,
     stanza_builder: TreeBuilder,
 }
 
 impl XMPPCodec {
     /// Constructor
     pub fn new() -> Self {
-        let tokenizer = Tokenizer::new();
         let stanza_builder = TreeBuilder::new();
         XMPPCodec {
             ns: None,
-            tokenizer,
             stanza_builder,
         }
     }
@@ -58,10 +55,7 @@ impl Decoder for XMPPCodec {
     type Error = Error;
 
     fn decode(&mut self, buf: &mut BytesMut) -> Result<Option<Self::Item>, Self::Error> {
-        self.tokenizer.push(buf);
-        buf.clear();
-
-        while let Some(token) = self.tokenizer.pull()? {
+        while let Some(token) = tokenize(buf)? {
             let had_stream_root = self.stanza_builder.depth() > 0;
             self.stanza_builder.process_token(token)?;
             let has_stream_root = self.stanza_builder.depth() > 0;
@@ -218,7 +212,6 @@ mod tests {
             Ok(Some(Packet::StreamStart(_))) => true,
             _ => false,
         });
-        b.clear();
         b.put_slice(b"</stream:stream>");
         let r = c.decode(&mut b);
         assert!(match r {
@@ -238,7 +231,6 @@ mod tests {
             _ => false,
         });
 
-        b.clear();
         b.put_slice("<test>ß</test".as_bytes());
         let r = c.decode(&mut b);
         assert!(match r {
@@ -246,7 +238,6 @@ mod tests {
             _ => false,
         });
 
-        b.clear();
         b.put_slice(b">");
         let r = c.decode(&mut b);
         assert!(match r {
@@ -266,7 +257,6 @@ mod tests {
             _ => false,
         });
 
-        b.clear();
         b.put(&b"<test>\xc3"[..]);
         let r = c.decode(&mut b);
         assert!(match r {
@@ -274,7 +264,6 @@ mod tests {
             _ => false,
         });
 
-        b.clear();
         b.put(&b"\x9f</test>"[..]);
         let r = c.decode(&mut b);
         assert!(match r {
@@ -295,7 +284,6 @@ mod tests {
             _ => false,
         });
 
-        b.clear();
         b.put_slice(b"<status xml:lang='en'>Test status</status>");
         let r = c.decode(&mut b);
         assert!(match r {
@@ -345,7 +333,6 @@ mod tests {
             _ => false,
         });
 
-        b.clear();
         b.put_slice(b"<message ");
         b.put_slice(b"type='chat'><body>Foo</body></message>");
         let r = c.decode(&mut b);