data_model: make endian types Serialize and Deserialize

By using these traits in crosvm, we also add serde as a dependency.

BUG=b:176847362
TEST=run_tests

Cq-Depend: chromium:2729637
Change-Id: Icd16a6e163d9e1dedbe3924cb94f29d777eb2216
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2613690
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Tested-by: Zach Reizner <zachr@chromium.org>
Commit-Queue: Zach Reizner <zachr@chromium.org>

Cargo.lock

@@ -230,6 +230,7 @@ version = "0.1.0"
 dependencies = [
  "assertions",
  "libc",
+ "serde",
 ]
 
 [[package]]
@@ -877,6 +878,26 @@ dependencies = [
  "sync",
 ]
 
+[[package]]
+name = "serde"
+version = "1.0.121"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6159e3c76cab06f6bc466244d43b35e77e9500cd685da87620addadc2a4c40b1"
+dependencies = [
+ "serde_derive",
+]
+
+[[package]]
+name = "serde_derive"
+version = "1.0.121"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f3fcab8778dc651bc65cfab2e4eb64996f3c912b74002fb379c94517e1f27c46"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "slab"
 version = "0.4.2"

data_model/Cargo.toml

@@ -8,5 +8,6 @@ include = ["src/**/*", "Cargo.toml"]
 [dependencies]
 assertions = { path = "../assertions" } # provided by ebuild
 libc = "*"
+serde = { version = "1", features = ["derive"] }
 
 [workspace]

data_model/src/endian.rs

@@ -30,9 +30,11 @@
 //!   assert_ne!(b_trans, l_trans);
 //! ```
 
-use assertions::const_assert;
 use std::mem::{align_of, size_of};
 
+use assertions::const_assert;
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
+
 use crate::DataInit;
 
 macro_rules! endian_type {
@@ -80,6 +82,24 @@ macro_rules! endian_type {
                 $new_type($old_type::$to_new(v))
             }
         }
+
+        impl Serialize for $new_type {
+            fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+            where
+                S: Serializer,
+            {
+                self.to_native().serialize(serializer)
+            }
+        }
+
+        impl<'de> Deserialize<'de> for $new_type {
+            fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+            where
+                D: Deserializer<'de>,
+            {
+                Ok($old_type::deserialize(deserializer)?.into())
+            }
+        }
     };
 }