Serde support (serialize feature flag)

Author: khvzak

.github/workflows/main.yml

@@ -27,7 +27,7 @@ jobs:
     - name: Build ${{ matrix.lua }} vendored
       run: |
         cargo build --release --features "${{ matrix.lua }} vendored"
-        cargo build --release --features "${{ matrix.lua }} vendored async send"
+        cargo build --release --features "${{ matrix.lua }} vendored async send serialize"
       shell: bash
     - name: Build ${{ matrix.lua }} pkg-config
       if: ${{ matrix.os == 'ubuntu-18.04' && matrix.lua != 'lua54' }}
@@ -63,13 +63,13 @@ jobs:
       if: ${{ matrix.os != 'macos-latest' || matrix.lua != 'luajit' }}
       run: |
         cargo test --release --features "${{ matrix.lua }} vendored"
-        cargo test --release --features "${{ matrix.lua }} vendored async send"
+        cargo test --release --features "${{ matrix.lua }} vendored async send serialize"
       shell: bash
     - name: Run compile tests (macos lua53)
       if: ${{ matrix.os == 'macos-latest' && matrix.lua == 'lua53' }}
       run: |
         TRYBUILD=overwrite cargo test --release --features "${{ matrix.lua }} vendored" -- --ignored
-        TRYBUILD=overwrite cargo test --release --features "${{ matrix.lua }} vendored async send" -- --ignored
+        TRYBUILD=overwrite cargo test --release --features "${{ matrix.lua }} vendored async send serialize" -- --ignored
       shell: bash
 
   test_luajit_macos:
@@ -85,12 +85,12 @@ jobs:
         override: true
     - name: Run LuaJIT 2.0.5 tests
       run: |
-        brew install luajit pkg-config
-        cargo test --tests --release --features "luajit async send" -- --test-threads=1
+        brew install luajit
+        cargo test --tests --release --features "luajit async send serialize" -- --test-threads=1
       shell: bash
     - name: Run LuaJIT vendored tests
       run: |
-        cargo test --release --features "luajit vendored async send"
+        cargo test --release --features "luajit vendored async send serialize"
       shell: bash
 
   test_modules:
@@ -126,21 +126,16 @@ jobs:
     needs: build
     strategy:
       matrix:
-        lua: [lua53, lua51, luajit]
+        lua: [lua53, luajit]
     defaults:
       run:
-        shell: bash.exe --login -eo pipefail "{0}"
-    env:
-      MSYSTEM: MINGW64
-      CHERE_INVOKING: 1
+        shell: msys2 {0}
     steps:
+    - uses: msys2/setup-msys2@v2
     - uses: actions/checkout@v2
-    - name: Set up shell
-      run: echo ::add-path::C:\msys64\usr\bin\
-      shell: pwsh
     - name: Install Rust & Lua
       run: |
-        pacman -S --noconfirm mingw-w64-x86_64-rust mingw-w64-x86_64-lua mingw-w64-x86_64-lua51 mingw-w64-x86_64-luajit
+        pacman -S --noconfirm mingw-w64-x86_64-rust mingw-w64-x86_64-lua mingw-w64-x86_64-luajit mingw-w64-x86_64-pkg-config
     - name: Run ${{ matrix.lua }} module tests
       run: |
         (cd examples/module && cargo build --release --features "${{ matrix.lua }}")
@@ -174,4 +169,4 @@ jobs:
       - uses: actions-rs/clippy-check@v1
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
-          args: --features "${{ matrix.lua }},async,send,vendored
+          args: --features "${{ matrix.lua }},vendored,async,send,serialize

Cargo.toml

@@ -40,6 +40,7 @@ vendored = ["lua-src", "luajit-src"]
 module = []
 async = ["futures-core", "futures-task", "futures-util"]
 send = []
+serialize = ["serde", "erased-serde"]
 
 [dependencies]
 bstr = { version = "0.2", features = ["std"], default_features = false }
@@ -48,6 +49,8 @@ num-traits = { version = "0.2.14" }
 futures-core = { version = "0.3.5", optional = true }
 futures-task = { version = "0.3.5", optional = true }
 futures-util = { version = "0.3.5", optional = true }
+serde = { version = "1.0", optional = true }
+erased-serde = { version = "0.3", optional = true }
 
 [build-dependencies]
 cc = { version = "1.0" }
@@ -63,6 +66,7 @@ futures = "0.3.5"
 hyper = "0.13"
 tokio = { version = "0.2", features = ["full"] }
 futures-timer = "3.0"
+serde_json = "1.0"
 
 [[bench]]
 name = "benchmark"

src/error.rs

@@ -105,6 +105,11 @@ pub enum Error {
     /// [`AnyUserData`]: struct.AnyUserData.html
     /// [`UserDataMethods`]: trait.UserDataMethods.html
     UserDataTypeMismatch,
+    /// An [`AnyUserData`] borrow failed because it has been destructed.
+    ///
+    /// This error can happen either due to to being destructed in a previous __gc, or due to being
+    /// destructed from exiting a `Lua::scope` call.
+    UserDataDestructed,
     /// An [`AnyUserData`] immutable borrow failed because it is already borrowed mutably.
     ///
     /// This error can occur when a method on a [`UserData`] type calls back into Lua, which then
@@ -132,6 +137,12 @@ pub enum Error {
         /// Original error returned by the Rust code.
         cause: Arc<Error>,
     },
+    /// Serialization error.
+    #[cfg(feature = "serialize")]
+    SerializeError(StdString),
+    /// Deserialization error.
+    #[cfg(feature = "serialize")]
+    DeserializeError(StdString),
     /// A custom error.
     ///
     /// This can be used for returning user-defined errors from callbacks.
@@ -206,6 +217,7 @@ impl fmt::Display for Error {
             }
             Error::CoroutineInactive => write!(fmt, "cannot resume inactive coroutine"),
             Error::UserDataTypeMismatch => write!(fmt, "userdata is not expected type"),
+            Error::UserDataDestructed => write!(fmt, "userdata has been destructed"),
             Error::UserDataBorrowError => write!(fmt, "userdata already mutably borrowed"),
             Error::UserDataBorrowMutError => write!(fmt, "userdata already borrowed"),
             Error::MismatchedRegistryKey => {
@@ -214,6 +226,14 @@ impl fmt::Display for Error {
             Error::CallbackError { ref traceback, .. } => {
                 write!(fmt, "callback error: {}", traceback)
             }
+            #[cfg(feature = "serialize")]
+            Error::SerializeError(ref err) => {
+                write!(fmt, "serialize error: {}", err)
+            },
+            #[cfg(feature = "serialize")]
+            Error::DeserializeError(ref err) => {
+                write!(fmt, "deserialize error: {}", err)
+            },
             Error::ExternalError(ref err) => write!(fmt, "{}", err),
         }
     }
@@ -289,3 +309,17 @@ impl std::convert::From<Utf8Error> for Error {
         Error::external(err)
     }
 }
+
+#[cfg(feature = "serialize")]
+impl serde::ser::Error for Error {
+    fn custom<T: fmt::Display>(msg: T) -> Self {
+        Self::SerializeError(msg.to_string())
+    }
+}
+
+#[cfg(feature = "serialize")]
+impl serde::de::Error for Error {
+    fn custom<T: fmt::Display>(msg: T) -> Self {
+        Self::DeserializeError(msg.to_string())
+    }
+}

src/hook.rs

@@ -37,7 +37,7 @@ impl<'a> Debug<'a> {
         }
     }
 
-    /// Corresponds to the `n` what mask.
+    /// Corresponds to the `S` what mask.
     pub fn source(&self) -> DebugSource<'a> {
         unsafe {
             mlua_assert!(

src/lib.rs

@@ -24,6 +24,18 @@
 //! The [`UserData`] trait can be implemented by user-defined types to make them available to Lua.
 //! Methods and operators to be used from Lua can be added using the [`UserDataMethods`] API.
 //!
+//! # Serde support
+//!
+//! The [`LuaSerdeExt`] trait implemented for [`Lua`] allow conversion from Rust types to Lua values
+//! and vice versa using serde. Any user defined data type that implements `serde::Serialize` or
+//! `serde::Deserialize` can be converted.
+//! For convenience, additional functionality to handle NULL values and arrays is provided.
+//!
+//! The [`Value`] struct implements `serde::Serialize` trait to support serializing Lua values
+//! (including [`UserData`]) into Rust values.
+//!
+//! Requires `feature = "serialize"`.
+//!
 //! # Async/await support
 //!
 //! The [`create_async_function`] allows creating non-blocking functions that returns [`Future`].
@@ -47,6 +59,8 @@
 //! [`FromLuaMulti`]: trait.FromLuaMulti.html
 //! [`UserData`]: trait.UserData.html
 //! [`UserDataMethods`]: trait.UserDataMethods.html
+//! [`LuaSerdeExt`]: trait.LuaSerdeExt.html
+//! [`Value`]: struct.Value.html
 //! [`create_async_function`]: struct.Lua.html#method.create_async_function
 //! [`call_async`]: struct.Function.html#method.call_async
 //! [`AsyncThread`]: struct.AsyncThread.html
@@ -95,4 +109,9 @@ pub use crate::value::{FromLua, FromLuaMulti, MultiValue, Nil, ToLua, ToLuaMulti
 #[cfg(feature = "async")]
 pub use crate::thread::AsyncThread;
 
+#[cfg(feature = "serialize")]
+pub use crate::serde::LuaSerdeExt;
+
 pub mod prelude;
+#[cfg(feature = "serialize")]
+pub mod serde;