From f35908815c30085c9ed64fae03e35498c432a161 Mon Sep 17 00:00:00 2001
From: trivernis <trivernis@protonmail.com>
Date: Sun, 7 Nov 2021 10:37:48 +0100
Subject: [PATCH] Add TandemPayload to store multiple payloads

Signed-off-by: trivernis <trivernis@protonmail.com>
---
 Cargo.lock            |  3 +-
 Cargo.toml            |  3 +-
 src/events/payload.rs | 69 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 73 insertions(+), 2 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index a7557c4d..392a3e7d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -500,8 +500,9 @@ dependencies = [
 
 [[package]]
 name = "rmp-ipc"
-version = "0.8.1"
+version = "0.8.2"
 dependencies = [
+ "byteorder",
  "criterion",
  "lazy_static",
  "rmp-serde",
diff --git a/Cargo.toml b/Cargo.toml
index a3a4a6fe..836934aa 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "rmp-ipc"
-version = "0.8.1"
+version = "0.8.2"
 authors = ["trivernis <trivernis@protonmail.com>"]
 edition = "2018"
 readme = "README.md"
@@ -25,6 +25,7 @@ rmp-serde = "0.15.4"
 tracing = "0.1.29"
 lazy_static = "1.4.0"
 typemap_rev = "0.1.5"
+byteorder = "1.4.3"
 
 [dependencies.serde]
 version = "1.0.130"
diff --git a/src/events/payload.rs b/src/events/payload.rs
index 5a793b9c..b066eb52 100644
--- a/src/events/payload.rs
+++ b/src/events/payload.rs
@@ -1,4 +1,5 @@
 use crate::prelude::IPCResult;
+use byteorder::{BigEndian, ReadBytesExt};
 use serde::de::DeserializeOwned;
 use serde::Serialize;
 use std::io::Read;
@@ -47,6 +48,11 @@ impl BytePayload {
     pub fn new(bytes: Vec<u8>) -> Self {
         Self { bytes }
     }
+
+    /// Returns the bytes of the payload
+    pub fn into_inner(self) -> Vec<u8> {
+        self.bytes
+    }
 }
 
 impl EventSendPayload for BytePayload {
@@ -63,3 +69,66 @@ impl EventReceivePayload for BytePayload {
         Ok(Self::new(buf))
     }
 }
+
+/// A payload wrapper that allows storing two different payloads
+/// independent from each other. For example one payload can be
+/// a payload serialized by serde while the other is a raw byte
+/// payload
+pub struct TandemPayload<P1, P2> {
+    load1: P1,
+    load2: P2,
+}
+
+impl<P1, P2> TandemPayload<P1, P2> {
+    pub fn new(load1: P1, load2: P2) -> Self {
+        Self { load1, load2 }
+    }
+
+    /// Returns both payload stored in the tandem payload
+    pub fn into_inner(self) -> (P1, P2) {
+        (self.load1, self.load2)
+    }
+}
+
+impl<P1, P2> EventSendPayload for TandemPayload<P1, P2>
+where
+    P1: EventSendPayload,
+    P2: EventSendPayload,
+{
+    fn to_payload_bytes(self) -> IPCResult<Vec<u8>> {
+        let mut p1_bytes = self.load1.to_payload_bytes()?;
+        let mut p2_bytes = self.load2.to_payload_bytes()?;
+
+        let mut p1_length_bytes = (p1_bytes.len() as u32).to_be_bytes().to_vec();
+        let mut p2_length_bytes = (p2_bytes.len() as u32).to_be_bytes().to_vec();
+
+        let mut bytes = Vec::new();
+        bytes.append(&mut p1_length_bytes);
+        bytes.append(&mut p1_bytes);
+        bytes.append(&mut p2_length_bytes);
+        bytes.append(&mut p2_bytes);
+
+        Ok(bytes)
+    }
+}
+
+impl<P1, P2> EventReceivePayload for TandemPayload<P1, P2>
+where
+    P1: EventReceivePayload,
+    P2: EventReceivePayload,
+{
+    fn from_payload_bytes<R: Read>(mut reader: R) -> IPCResult<Self> {
+        let p1_length = reader.read_u32::<BigEndian>()?;
+        let mut load1_bytes = vec![0u8; p1_length as usize];
+        reader.read_exact(&mut load1_bytes)?;
+
+        let p2_length = reader.read_u32::<BigEndian>()?;
+        let mut load2_bytes = vec![0u8; p2_length as usize];
+        reader.read_exact(&mut load2_bytes)?;
+
+        Ok(Self {
+            load1: P1::from_payload_bytes(load1_bytes.as_slice())?,
+            load2: P2::from_payload_bytes(load2_bytes.as_slice())?,
+        })
+    }
+}