Utilize Writer size hinting in message fuzz targets and check them

[rust-lightning] / fuzz / fuzz_targets / msg_targets / utils.rs

diff --git a/fuzz/fuzz_targets/msg_targets/utils.rs b/fuzz/fuzz_targets/msg_targets/utils.rs
index 52ea530cf9fed976438e30f5ad1beff30ac94af7..a5257ba0f80c1fea24f399018103da37f572c763 100644 (file)
--- a/fuzz/fuzz_targets/msg_targets/utils.rs
+++ b/fuzz/fuzz_targets/msg_targets/utils.rs
@@ -1,5 +1,18 @@
 #![macro_use]
 
+use lightning::util::ser::Writer;
+pub struct VecWriter(pub Vec<u8>);
+impl Writer for VecWriter {
+       fn write_all(&mut self, buf: &[u8]) -> Result<(), ::std::io::Error> {
+               assert!(self.0.capacity() >= self.0.len() + buf.len());
+               self.0.extend_from_slice(buf);
+               Ok(())
+       }
+       fn size_hint(&mut self, size: usize) {
+               self.0.reserve_exact(size);
+       }
+}
+
 #[macro_export]
 macro_rules! test_msg {
        ($MsgType: path, $data: ident) => {
@@ -8,12 +21,11 @@ macro_rules! test_msg {
                        let mut r = ::std::io::Cursor::new($data);
                        if let Ok(msg) = <$MsgType as Readable<::std::io::Cursor<&[u8]>>>::read(&mut r) {
                                let p = r.position() as usize;
-                               let mut w = ::std::io::Cursor::new(vec![]);
+                               let mut w = VecWriter(Vec::new());
                                msg.write(&mut w).unwrap();
 
-                               let buf = w.into_inner();
-                               assert_eq!(buf.len(), p);
-                               assert_eq!(&r.into_inner()[..p], &buf[..p]);
+                               assert_eq!(w.0.len(), p);
+                               assert_eq!(&r.into_inner()[..p], &w.0[..p]);
                        }
                }
        }
@@ -26,7 +38,8 @@ macro_rules! test_msg_simple {
                        use lightning::util::ser::{Writeable, Readable};
                        let mut r = ::std::io::Cursor::new($data);
                        if let Ok(msg) = <$MsgType as Readable<::std::io::Cursor<&[u8]>>>::read(&mut r) {
-                               msg.write(&mut ::std::io::Cursor::new(vec![])).unwrap();
+                               let mut w = VecWriter(Vec::new());
+                               msg.write(&mut w).unwrap();
                        }
                }
        }
@@ -39,11 +52,10 @@ macro_rules! test_msg_exact {
                        use lightning::util::ser::{Writeable, Readable};
                        let mut r = ::std::io::Cursor::new($data);
                        if let Ok(msg) = <$MsgType as Readable<::std::io::Cursor<&[u8]>>>::read(&mut r) {
-                               let mut w = ::std::io::Cursor::new(vec![]);
+                               let mut w = VecWriter(Vec::new());
                                msg.write(&mut w).unwrap();
 
-                               let buf = w.into_inner();
-                               assert_eq!(&r.into_inner()[..], &buf[..]);
+                               assert_eq!(&r.into_inner()[..], &w.0[..]);
                        }
                }
        }
@@ -56,14 +68,13 @@ macro_rules! test_msg_hole {
                        use lightning::util::ser::{Writeable, Readable};
                        let mut r = ::std::io::Cursor::new($data);
                        if let Ok(msg) = <$MsgType as Readable<::std::io::Cursor<&[u8]>>>::read(&mut r) {
-                               let mut w = ::std::io::Cursor::new(vec![]);
+                               let mut w = VecWriter(Vec::new());
                                msg.write(&mut w).unwrap();
-                               let p = w.position() as usize;
+                               let p = w.0.len() as usize;
 
-                               let buf = w.into_inner();
-                               assert_eq!(buf.len(),p);
-                               assert_eq!(&r.get_ref()[..$hole], &buf[..$hole]);
-                               assert_eq!(&r.get_ref()[$hole+$hole_len..p], &buf[$hole+$hole_len..]);
+                               assert_eq!(w.0.len(), p);
+                               assert_eq!(&r.get_ref()[..$hole], &w.0[..$hole]);
+                               assert_eq!(&r.get_ref()[$hole+$hole_len..p], &w.0[$hole+$hole_len..]);
                        }
                }
        }