buffered-reader: New predicate BufferedReader::consummated.

2 files changed, 39 insertions, 0 deletions

diff --git a/buffered-reader/src/lib.rs b/buffered-reader/src/lib.rs
index 297d1b79..764cec99 100644
--- a/buffered-reader/src/lib.rs
+++ b/buffered-reader/src/lib.rs
@@ -565,6 +565,23 @@ pub trait BufferedReader<C> : io::Read + fmt::Debug + fmt::Display {
         self.data_hard(1).is_err()
     }
 
+    /// Checks whether this reader is consummated.
+    ///
+    /// For most readers, this function will return true once the end
+    /// of the stream is reached.  However, some readers are concerned
+    /// with packet framing (e.g. the [`Limitor`]).  Those readers
+    /// consider themselves consummated if the amount of data
+    /// indicated by the packet frame is consumed.
+    ///
+    /// This allows us to detect truncation.  A packet is truncated,
+    /// iff the end of the stream is reached, but the reader is not
+    /// consummated.
+    ///
+    /// [`Limitor`]: struct.Limitor.html
+    fn consummated(&mut self) -> bool {
+        self.eof()
+    }
+
     /// A convenience function for reading a 16-bit unsigned integer
     /// in big endian format.
     fn read_be_u16(&mut self) -> Result<u16, std::io::Error> {
@@ -816,6 +833,10 @@ impl <'a, C> BufferedReader<C> for Box<BufferedReader<C> + 'a> {
         return self.as_mut().data_consume_hard(amount);
     }
 
+    fn consummated(&mut self) -> bool {
+        self.as_mut().consummated()
+    }
+
     fn read_be_u16(&mut self) -> Result<u16, std::io::Error> {
         return self.as_mut().read_be_u16();
     }
diff --git a/buffered-reader/src/limitor.rs b/buffered-reader/src/limitor.rs
index 78fcd34a..7c371467 100644
--- a/buffered-reader/src/limitor.rs
+++ b/buffered-reader/src/limitor.rs
@@ -120,6 +120,10 @@ impl<'a, C> BufferedReader<C> for Limitor<'a, C> {
         return result;
     }
 
+    fn consummated(&mut self) -> bool {
+        self.limit == 0
+    }
+
     fn get_mut(&mut self) -> Option<&mut BufferedReader<C>> {
         Some(&mut self.reader)
     }
@@ -288,4 +292,18 @@ mod test {
             }
         }
     }
+
+    #[test]
+    fn consummated() {
+        let data = b"0123456789";
+
+        let mut l = Limitor::new(Box::new(Memory::new(data)), 10);
+        l.drop_eof().unwrap();
+        assert!(l.consummated());
+
+        let mut l = Limitor::new(Box::new(Memory::new(data)), 20);
+        l.drop_eof().unwrap();
+        eprintln!("{:?}", l);
+        assert!(! l.consummated());
+    }
 }