From 3968c3a4cda41c7f2f07479389e5405f0162679e Mon Sep 17 00:00:00 2001
From: Mark Poliakov <mark@alnyan.me>
Date: Mon, 9 Dec 2024 10:21:15 +0200
Subject: [PATCH] ipc: flexbuffers -> postcard

---
 userspace/Cargo.lock               | 212 ++++++++++++-----------------
 userspace/Cargo.toml               |   2 +-
 userspace/colors/Cargo.toml        |   1 -
 userspace/lib/serde-ipc/Cargo.toml |   2 +-
 userspace/lib/serde-ipc/src/lib.rs |  18 ++-
 5 files changed, 100 insertions(+), 135 deletions(-)

diff --git a/userspace/Cargo.lock b/userspace/Cargo.lock
index a6713fca..6f260fae 100644
--- a/userspace/Cargo.lock
+++ b/userspace/Cargo.lock
@@ -8,7 +8,7 @@ version = "0.1.0"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.86",
+ "syn",
  "thiserror",
 ]
 
@@ -91,6 +91,15 @@ version = "0.7.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7c02d123df017efcdfbd739ef81735b36c5ba83ec3c59c80a9d7ecc718f92e50"
 
+[[package]]
+name = "atomic-polyfill"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8cf2bce30dfe09ef0bfaef228b9d414faaf7e563035494d7fe092dba54b300f4"
+dependencies = [
+ "critical-section",
+]
+
 [[package]]
 name = "autocfg"
 version = "1.4.0"
@@ -103,12 +112,6 @@ version = "1.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8c3c1a368f70d6cf7302d78f8f7093da241fb8e8807c05cc9e51a125895a6d5b"
 
-[[package]]
-name = "bitflags"
-version = "1.3.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
-
 [[package]]
 name = "bitflags"
 version = "2.6.0"
@@ -141,7 +144,7 @@ checksum = "bcfcc3cd946cb52f0bbfdbbcfa2f4e24f75ebb6c0e1002f7c25904fada18b9ec"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.86",
+ "syn",
 ]
 
 [[package]]
@@ -228,7 +231,7 @@ dependencies = [
  "heck",
  "proc-macro2",
  "quote",
- "syn 2.0.86",
+ "syn",
 ]
 
 [[package]]
@@ -237,6 +240,12 @@ version = "0.7.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1462739cb27611015575c0c11df5df7601141071f07518d56fcc1be504cbec97"
 
+[[package]]
+name = "cobs"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "67ba02a97a2bd10f4b59b25c7973101c79642302776489e030cd13cdab09ed15"
+
 [[package]]
 name = "colorchoice"
 version = "1.0.3"
@@ -247,7 +256,6 @@ checksum = "5b63caa9aa9397e2d9480a9b13673856c78d8ac123288526c37d7839f2a86990"
 name = "colors"
 version = "0.1.0"
 dependencies = [
- "flexbuffers",
  "lazy_static",
  "libcolors",
  "serde",
@@ -271,6 +279,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "critical-section"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "790eea4361631c5e7d22598ecd5723ff611904e3344ce8720784c93e3d83d40b"
+
 [[package]]
 name = "cross"
 version = "0.1.0"
@@ -284,7 +298,7 @@ version = "0.27.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f476fe445d41c9e991fd07515a6f463074b782242ccf4a5b7b1d1012e70824df"
 dependencies = [
- "bitflags 2.6.0",
+ "bitflags",
  "crossterm_winapi",
  "libc",
  "mio",
@@ -346,7 +360,7 @@ source = "git+https://git.alnyan.me/yggdrasil/curve25519-dalek.git?branch=alnyan
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.86",
+ "syn",
 ]
 
 [[package]]
@@ -422,6 +436,18 @@ version = "0.7.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4445909572dbd556c457c849c4ca58623d84b27c8fff1e74b0b4227d8b90d17b"
 
+[[package]]
+name = "embedded-io"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ef1a6892d9eef45c8fa6b9e0086428a2cca8491aca8f787c534a3d6d0bcb3ced"
+
+[[package]]
+name = "embedded-io"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "edd0f118536f44f5ccd48bcb8b111bdc3de888b58c74639dfb034a357d0f206d"
+
 [[package]]
 name = "env_filter"
 version = "0.1.2"
@@ -445,12 +471,6 @@ dependencies = [
  "log",
 ]
 
-[[package]]
-name = "equivalent"
-version = "1.0.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5443807d6dff69373d433ab9ef5378ad8df50ca6298caf15de6e52e24aaf54d5"
-
 [[package]]
 name = "errno"
 version = "0.3.9"
@@ -491,19 +511,6 @@ version = "0.2.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "28dea519a9695b9977216879a3ebfddf92f1c08c05d984f8996aecd6ecdc811d"
 
-[[package]]
-name = "flexbuffers"
-version = "2.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "15d14128f06405808ce75bfebe11e9b0f9da18719ede6d7bdb1702d6bfe0f7e8"
-dependencies = [
- "bitflags 1.3.2",
- "byteorder",
- "num_enum",
- "serde",
- "serde_derive",
-]
-
 [[package]]
 name = "fnv"
 version = "1.0.7"
@@ -533,7 +540,7 @@ checksum = "162ee34ebcb7c64a8abebc059ce0fee27c2262618d7b60ed8faf72fef13c3650"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.86",
+ "syn",
 ]
 
 [[package]]
@@ -588,10 +595,27 @@ dependencies = [
 ]
 
 [[package]]
-name = "hashbrown"
-version = "0.15.0"
+name = "hash32"
+version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1e087f84d4f86bf4b218b927129862374b72199ae7d8657835f1e89000eea4fb"
+checksum = "b0c35f58762feb77d74ebe43bdbc3210f09be9fe6742234d573bacc26ed92b67"
+dependencies = [
+ "byteorder",
+]
+
+[[package]]
+name = "heapless"
+version = "0.7.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cdc6457c0eb62c71aac4bc17216026d8410337c4126773b9c5daba343f17964f"
+dependencies = [
+ "atomic-polyfill",
+ "hash32",
+ "rustc_version",
+ "serde",
+ "spin",
+ "stable_deref_trait",
+]
 
 [[package]]
 name = "heck"
@@ -655,16 +679,6 @@ dependencies = [
  "unicode-normalization",
 ]
 
-[[package]]
-name = "indexmap"
-version = "2.6.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "707907fe3c25f5424cce2cb7e1cbcafee6bdbe735ca90ef77c29e84591e5b9da"
-dependencies = [
- "equivalent",
- "hashbrown",
-]
-
 [[package]]
 name = "init"
 version = "0.1.0"
@@ -877,27 +891,6 @@ dependencies = [
  "libm",
 ]
 
-[[package]]
-name = "num_enum"
-version = "0.5.11"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1f646caf906c20226733ed5b1374287eb97e3c2a5c227ce668c1f2ce20ae57c9"
-dependencies = [
- "num_enum_derive",
-]
-
-[[package]]
-name = "num_enum_derive"
-version = "0.5.11"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dcbff9bc912032c62bf65ef1d5aea88983b420f4f839db1e9b0c281a25c9c799"
-dependencies = [
- "proc-macro-crate",
- "proc-macro2",
- "quote",
- "syn 1.0.109",
-]
-
 [[package]]
 name = "num_threads"
 version = "0.1.7"
@@ -984,6 +977,19 @@ dependencies = [
  "spki",
 ]
 
+[[package]]
+name = "postcard"
+version = "1.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "170a2601f67cc9dba8edd8c4870b15f71a6a2dc196daec8c83f72b59dff628a8"
+dependencies = [
+ "cobs",
+ "embedded-io 0.4.0",
+ "embedded-io 0.6.1",
+ "heapless",
+ "serde",
+]
+
 [[package]]
 name = "powerfmt"
 version = "0.2.0"
@@ -1006,17 +1012,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "64d1ec885c64d0457d564db4ec299b2dae3f9c02808b8ad9c3a089c591b18033"
 dependencies = [
  "proc-macro2",
- "syn 2.0.86",
-]
-
-[[package]]
-name = "proc-macro-crate"
-version = "1.3.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7f4c021e1093a56626774e81216a4ce732a735e5bad4868a03f3ed65ca0c3919"
-dependencies = [
- "once_cell",
- "toml_edit",
+ "syn",
 ]
 
 [[package]]
@@ -1154,7 +1150,7 @@ version = "0.5.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9b6dfecf2c74bce2466cabf93f6664d6998a69eb21e39f4207930065b27b771f"
 dependencies = [
- "bitflags 2.6.0",
+ "bitflags",
 ]
 
 [[package]]
@@ -1244,7 +1240,7 @@ version = "0.38.38"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "aa260229e6538e52293eeb577aabd09945a09d6d9cc0fc550ed7529056c2e32a"
 dependencies = [
- "bitflags 2.6.0",
+ "bitflags",
  "errno",
  "libc",
  "linux-raw-sys",
@@ -1282,7 +1278,7 @@ dependencies = [
 name = "serde-ipc"
 version = "0.1.0"
 dependencies = [
- "flexbuffers",
+ "postcard",
  "serde",
  "tempfile",
  "thiserror",
@@ -1296,7 +1292,7 @@ checksum = "de523f781f095e28fa605cdce0f8307e451cc0fd14e2eb4cd2e98a355b147766"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.86",
+ "syn",
 ]
 
 [[package]]
@@ -1408,6 +1404,9 @@ name = "spin"
 version = "0.9.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6980e8d7511241f8acf4aebddbb1ff938df5eebe98691418c4468d0b72a96a67"
+dependencies = [
+ "lock_api",
+]
 
 [[package]]
 name = "spki"
@@ -1425,6 +1424,12 @@ version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "02a8428da277a8e3a15271d79943e80ccc2ef254e78813a166a08d65e4c3ece5"
 
+[[package]]
+name = "stable_deref_trait"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a8f112729512f8e442d81f95a8a7ddf2b7c6b8a1a6f509a95864142b30cab2d3"
+
 [[package]]
 name = "subtle"
 version = "2.6.1"
@@ -1437,17 +1442,6 @@ version = "0.7.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9ac8fb7895b4afa060ad731a32860db8755da3449a47e796d5ecf758db2671d4"
 
-[[package]]
-name = "syn"
-version = "1.0.109"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "72b64191b275b66ffe2469e8af2c1cfe3bafa67b529ead792a6d0160888b4237"
-dependencies = [
- "proc-macro2",
- "quote",
- "unicode-ident",
-]
-
 [[package]]
 name = "syn"
 version = "2.0.86"
@@ -1530,7 +1524,7 @@ checksum = "b08be0f17bd307950653ce45db00cd31200d82b624b36e181337d9c7d92765b5"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.86",
+ "syn",
 ]
 
 [[package]]
@@ -1581,23 +1575,6 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1f3ccbac311fea05f86f61904b462b55fb3df8837a366dfc601a0161d0532f20"
 
-[[package]]
-name = "toml_datetime"
-version = "0.6.8"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0dd7358ecb8fc2f8d014bf86f6f638ce72ba252a2c3a2572f2a795f1d23efb41"
-
-[[package]]
-name = "toml_edit"
-version = "0.19.15"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1b5bb770da30e5cbfde35a2d7b9b8a2c4b8ef89548a7a6aeab5c9a576e3e7421"
-dependencies = [
- "indexmap",
- "toml_datetime",
- "winnow",
-]
-
 [[package]]
 name = "typed-arena"
 version = "2.0.2"
@@ -1836,15 +1813,6 @@ version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"
 
-[[package]]
-name = "winnow"
-version = "0.5.40"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f593a95398737aeed53e489c785df13f3618e41dbcd6718c6addbf1395aa6876"
-dependencies = [
- "memchr",
-]
-
 [[package]]
 name = "x25519-dalek"
 version = "2.0.1"
@@ -1914,7 +1882,7 @@ checksum = "fa4f8080344d4671fb4e831a13ad1e68092748387dfc4f55e356242fae12ce3e"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.86",
+ "syn",
 ]
 
 [[package]]
@@ -1925,7 +1893,7 @@ checksum = "3cd137b4cc21bde6ecce3bbbb3350130872cda0be2c6888874279ea76e17d4c1"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.86",
+ "syn",
 ]
 
 [[package]]
@@ -1945,5 +1913,5 @@ checksum = "ce36e65b0d2999d2aafac989fb249189a141aee1f53c612c1f37d72631959f69"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.86",
+ "syn",
 ]
diff --git a/userspace/Cargo.toml b/userspace/Cargo.toml
index a5df70e1..c05f18db 100644
--- a/userspace/Cargo.toml
+++ b/userspace/Cargo.toml
@@ -28,9 +28,9 @@ serde_json = "1.0.132"
 serde = { version = "1.0.214", features = ["derive"] }
 bytemuck = "1.19.0"
 thiserror = "1.0.64"
-flexbuffers = "2.0.0"
 sha2 = { version = "0.10.8" }
 chrono = { version = "0.4.31", default-features = false }
+postcard = { version = "1.1.1", features = ["alloc"] }
 
 # Vendored/patched dependencies
 rand = { git = "https://git.alnyan.me/yggdrasil/rand.git", branch = "alnyan/yggdrasil" }
diff --git a/userspace/colors/Cargo.toml b/userspace/colors/Cargo.toml
index 066478ac..b2ec65ba 100644
--- a/userspace/colors/Cargo.toml
+++ b/userspace/colors/Cargo.toml
@@ -8,7 +8,6 @@ authors = ["Mark Poliakov <mark@alnyan.me>"]
 yggdrasil-abi.workspace = true
 serde-ipc.workspace = true
 serde.workspace = true
-flexbuffers.workspace = true
 thiserror.workspace = true
 libcolors = { workspace = true, default-features = false }
 
diff --git a/userspace/lib/serde-ipc/Cargo.toml b/userspace/lib/serde-ipc/Cargo.toml
index 5c9ba247..416970ae 100644
--- a/userspace/lib/serde-ipc/Cargo.toml
+++ b/userspace/lib/serde-ipc/Cargo.toml
@@ -5,7 +5,7 @@ edition = "2021"
 authors = ["Mark Poliakov <mark@alnyan.me>"]
 
 [dependencies]
-flexbuffers.workspace = true
+postcard.workspace = true
 serde.workspace = true
 thiserror.workspace = true
 
diff --git a/userspace/lib/serde-ipc/src/lib.rs b/userspace/lib/serde-ipc/src/lib.rs
index bd5c38cc..71164522 100644
--- a/userspace/lib/serde-ipc/src/lib.rs
+++ b/userspace/lib/serde-ipc/src/lib.rs
@@ -18,12 +18,10 @@ use crate::sys::IpcSender;
 
 #[derive(thiserror::Error, Debug)]
 pub enum Error {
-    #[error("Serialization error: {0}")]
-    SerializeError(flexbuffers::SerializationError),
-    #[error("Deserialization error: {0}")]
-    DeserializeError(flexbuffers::DeserializationError),
+    #[error("Ser/des error: {0}")]
+    Serialize(postcard::Error),
     #[error("I/O error: {0}")]
-    IoError(#[from] io::Error),
+    Io(#[from] io::Error),
 }
 
 pub struct Sender<M: Serialize> {
@@ -90,10 +88,10 @@ pub fn connect<T: Serialize, U: DeserializeOwned, P: AsRef<std::path::Path>>(
 
 impl<T: Serialize> Sender<T> {
     pub fn send_to(&self, message: &T, peer: &PeerAddr) -> Result<(), Error> {
-        let message = flexbuffers::to_vec(message).map_err(Error::SerializeError)?;
+        let message = postcard::to_allocvec(message).map_err(Error::Serialize)?;
         self.inner
             .send_message_to(&message, peer)
-            .map_err(Error::IoError)
+            .map_err(Error::Io)
     }
 
     #[inline]
@@ -102,7 +100,7 @@ impl<T: Serialize> Sender<T> {
     }
 
     pub fn send_file_to<F: AsRawFd>(&self, file: &F, peer: &PeerAddr) -> Result<(), Error> {
-        self.inner.send_file_to(file, peer).map_err(Error::IoError)
+        self.inner.send_file_to(file, peer).map_err(Error::Io)
     }
 }
 
@@ -116,8 +114,8 @@ impl<U: DeserializeOwned> Receiver<U> {
     pub fn receive(&mut self) -> Result<(PeerAddr, Either<U, OwnedFd>), Error> {
         let (peer, message) = self.inner.receive(&mut self.buffer)?;
         let message = message
-            .try_map_left(|len| flexbuffers::from_slice(&self.buffer[..len]))
-            .map_err(Error::DeserializeError)?;
+            .try_map_left(|len| postcard::from_bytes(&self.buffer[..len]))
+            .map_err(Error::Serialize)?;
         Ok((peer, message))
     }