Factor transport frame handling more

disk/src/frame/inmem.rs

@@ -216,6 +216,16 @@ impl InMemoryFrame {
     }
 }
 
+impl std::fmt::Debug for InMemoryFrame {
+    fn fmt(&self, fmt: &mut std::fmt::Formatter) -> std::fmt::Result {
+        write!(
+            fmt,
+            "InMemoryFrame {{ encid: {:x}  tyid: {:x}  len {} }}",
+            self.encid, self.tyid, self.len
+        )
+    }
+}
+
 impl<T> Stream for InMemoryFrameAsyncReadStream<T>
 where
     T: AsyncRead + Unpin,

disk/src/frame/makeframe.rs

@@ -1,9 +1,10 @@
 use crate::cache::BinnedBytesForHttpStreamFrame;
+use crate::frame::inmem::InMemoryFrame;
 use crate::raw::conn::RawConnOut;
 use crate::raw::EventQueryJsonStringFrame;
 use bytes::{BufMut, BytesMut};
 use err::Error;
-use serde::Serialize;
+use serde::{Deserialize, Serialize};
 
 pub const INMEM_FRAME_HEAD: usize = 16;
 pub const INMEM_FRAME_MAGIC: u32 = 0xc6c3b73d;
@@ -55,3 +56,31 @@ pub fn make_term_frame() -> BytesMut {
     buf.put_u32_le(0);
     buf
 }
+
+pub fn decode_frame<'a, FT>(frame: &'a InMemoryFrame) -> Result<FT, Error>
+where
+    FT: FrameType + Deserialize<'a>,
+{
+    if frame.encid() != 0x12121212 {
+        return Err(Error::with_msg(format!("unknown encoder id {:?}", frame)));
+    }
+    if frame.tyid() != FT::FRAME_TYPE_ID {
+        return Err(Error::with_msg(format!(
+            "type id mismatch expect {}  found {:?}",
+            FT::FRAME_TYPE_ID,
+            frame
+        )));
+    }
+    if frame.len() as usize != frame.buf().len() {
+        return Err(Error::with_msg(format!(
+            "buf mismatch  {}  vs  {}  in {:?}",
+            frame.len(),
+            frame.buf().len(),
+            frame
+        )));
+    }
+    match bincode::deserialize(frame.buf()) {
+        Ok(item) => Ok(item),
+        Err(e) => Err(e.into()),
+    }
+}