from_buffer(): Implemented.

Fortune for rsh's current commit: Great blessing − 大吉

src/message/binary.rs

@@ -73,9 +73,75 @@ impl<V: ?Sized + MessageValue> SerializedMessage<V>
     ///
     /// # Panics
     /// If `bytes` does not contain enough data to read.
-    pub fn from_buffer(bytes: impl Buf) -> eyre::Result<Self>
+    pub fn from_buffer(mut bytes: impl Buf) -> eyre::Result<Self>
     {
-	todo!()
+	macro_rules! read {
+	    ($bref:expr) => {
+		{
+		    let by: &mut [u8] = ($bref).as_mut();
+		    bytes.copy_to_slice(by);
+		}
+	    };
+	    (? $odef:expr) => {
+		{
+		    let by = bytes.get_u8();
+		    match by {
+			0 => None,
+			1 => {
+			    let mut def = $odef;
+			    read!(&mut def);
+			    Some(def)
+			},
+			x => {
+			    return Err(eyre!("Invalid optional-set bit: {}", x));
+			}
+		    }
+		}
+	    };
+	    (: $ser:ty) => {
+		{
+		    let len = usize::try_from(bytes.get_u64())?;
+		    if len > MAX_ALLOC_SIZE {
+			return Err(eyre!("Invalid length read: {}", len)
+				   .with_section(|| format!("Max length read: {}", MAX_ALLOC_SIZE)))
+		    }
+		    alloc_local_bytes(len, |de| {
+			read!(&mut de[..]);
+			serde_cbor::from_slice::<$ser>(&de[..]).wrap_err(eyre!("Failed to deserialise {} from reader", std::any::type_name::<$ser>()))
+		    })?
+			
+		}
+	    };
+	    ($into:expr, $num:expr) => {
+		{
+		    let num = $num;
+		    let reader = (&mut bytes).reader();
+		    copy_buffer($into, reader, num).wrap_err(eyre!("Failed to read {} bytes from reader", num))?
+		}
+	    }
+	}
+
+	let header = read!(: SerHeader);
+	let data_len = usize::try_from(bytes.get_u64())?;
+	let mut data = Vec::with_capacity(std::cmp::min(data_len, MAX_ALLOC_SIZE)); //XXX: Redesign so we don't allocate OR try to read massive buffers by accident on corrupted/malformed messages
+	read!(&mut data, data_len);
+	if data.len()!=data_len {
+	    return Err(eyre!("Failed to read {} bytes from buffer (got {})", data_len, data.len()));
+	}
+	let mut hash = sha256::Sha256Hash::default();
+	read!(&mut hash);
+	let enc_key: Option<[u8; RSA_BLOCK_SIZE]> = read!(? [0u8; RSA_BLOCK_SIZE]);
+	let sig: Option<rsa::Signature> = read!(? rsa::Signature::default());
+
+	Ok(Self {
+	    header,
+	    data,
+	    hash,
+	    enc_key,
+	    sig,
+
+	    _phantom: PhantomData,
+	})
     }
 
     /// Create from a slice of bytes