feat(c): proof of concept of C api

will be long and unpleasant but feasible

Cargo.lock

@@ -86,6 +86,17 @@ version = "1.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1505bd5d3d116872e7271a6d4e16d81d0c8570876c8de68093a09ac269d8aac0"
 
+[[package]]
+name = "atty"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
+dependencies = [
+ "hermit-abi 0.1.19",
+ "libc",
+ "winapi",
+]
+
 [[package]]
 name = "autocfg"
 version = "1.3.0"
@@ -160,6 +171,12 @@ version = "0.22.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "72b3254f16251a8381aa12e40e3c4d2f0199f8c6508fbecb9d91f575e0fbb8c6"
 
+[[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"
@@ -194,6 +211,25 @@ version = "1.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8318a53db07bb3f8dca91a600466bdb3f2eaadeedfdbcf02e1accbad9271ba50"
 
+[[package]]
+name = "cbindgen"
+version = "0.24.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4b922faaf31122819ec80c4047cc684c6979a087366c069611e33649bf98e18d"
+dependencies = [
+ "clap",
+ "heck 0.4.1",
+ "indexmap 1.9.3",
+ "log",
+ "proc-macro2",
+ "quote",
+ "serde",
+ "serde_json",
+ "syn 1.0.109",
+ "tempfile",
+ "toml",
+]
+
 [[package]]
 name = "cc"
 version = "1.1.20"
@@ -229,11 +265,36 @@ dependencies = [
  "windows-targets 0.52.6",
 ]
 
+[[package]]
+name = "clap"
+version = "3.2.25"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4ea181bf566f71cb9a5d17a59e1871af638180a18fb0035c92ae62b705207123"
+dependencies = [
+ "atty",
+ "bitflags 1.3.2",
+ "clap_lex",
+ "indexmap 1.9.3",
+ "strsim",
+ "termcolor",
+ "textwrap",
+]
+
+[[package]]
+name = "clap_lex"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2850f2f5a82cbf437dd5af4d49848fbdfc27c157c3d010345776f952765261c5"
+dependencies = [
+ "os_str_bytes",
+]
+
 [[package]]
 name = "codemp"
 version = "0.7.2"
 dependencies = [
  "async-trait",
+ "cbindgen",
  "codemp-proto",
  "dashmap",
  "diamond-types",
@@ -531,12 +592,27 @@ version = "0.14.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e5274423e17b7c9fc20b6e7e208532f9b19825d82dfd615708b70edd83df41f1"
 
+[[package]]
+name = "heck"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "95505c38b4572b2d910cecb0281560f54b440a19336cbbcb27bf6ce6adc6f5a8"
+
 [[package]]
 name = "heck"
 version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2304e00983f87ffb38b55b444b5e3b60a884b5d30c0fca7d82fe33449bbe55ea"
 
+[[package]]
+name = "hermit-abi"
+version = "0.1.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "62b467343b94ba476dcb2500d242dadbb39557df889310ac77c5d99100aaac33"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "hermit-abi"
 version = "0.3.9"
@@ -893,7 +969,7 @@ version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "80e04d1dcff3aae0704555fe5fee3bcfaf3d1fdf8a7e521d5b9d2b42acb52cec"
 dependencies = [
- "hermit-abi",
+ "hermit-abi 0.3.9",
  "libc",
  "wasi",
  "windows-sys 0.52.0",
@@ -950,7 +1026,7 @@ version = "2.16.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "04409e8c2d61995696e44d2181b79b68c1dd41f7e24a17cde60bbd9f54ddddef"
 dependencies = [
- "bitflags",
+ "bitflags 2.6.0",
  "chrono",
  "ctor",
  "encoding_rs",
@@ -1076,6 +1152,12 @@ dependencies = [
  "num-traits",
 ]
 
+[[package]]
+name = "os_str_bytes"
+version = "6.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2355d85b9a3786f481747ced0e0ff2ba35213a1f9bd406ed906554d7af805a1"
+
 [[package]]
 name = "overload"
 version = "0.1.1"
@@ -1220,7 +1302,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f8650aabb6c35b860610e9cff5dc1af886c9e25073b7b1712a68972af4281302"
 dependencies = [
  "bytes",
- "heck",
+ "heck 0.5.0",
  "itertools",
  "log",
  "multimap",
@@ -1312,7 +1394,7 @@ version = "0.22.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1be962f0e06da8f8465729ea2cb71a416d2257dff56cbe40a70d3e62a93ae5d1"
 dependencies = [
- "heck",
+ "heck 0.5.0",
  "proc-macro2",
  "pyo3-build-config",
  "quote",
@@ -1364,7 +1446,7 @@ version = "0.5.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0884ad60e090bf1345b93da0a5de8923c93884cd03f40dfcfddd3b4bee661853"
 dependencies = [
- "bitflags",
+ "bitflags 2.6.0",
 ]
 
 [[package]]
@@ -1438,7 +1520,7 @@ version = "0.38.37"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8acb788b847c24f28525660c4d7758620a7210875711f79e7f663cc152726811"
 dependencies = [
- "bitflags",
+ "bitflags 2.6.0",
  "errno",
  "libc",
  "linux-raw-sys",
@@ -1542,7 +1624,7 @@ version = "2.11.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "897b2245f0b511c87893af39b033e5ca9cce68824c4d7e7630b5a1d339658d02"
 dependencies = [
- "bitflags",
+ "bitflags 2.6.0",
  "core-foundation",
  "core-foundation-sys",
  "libc",
@@ -1682,6 +1764,12 @@ version = "0.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e9557cb6521e8d009c51a8666f09356f4b817ba9ba0981a305bd86aee47bd35c"
 
+[[package]]
+name = "strsim"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "73473c0e59e6d5812c5dfe2a064a6444949f089e20eec9a2e5506596494e4623"
+
 [[package]]
 name = "subtle"
 version = "2.6.1"
@@ -1741,6 +1829,21 @@ dependencies = [
  "windows-sys 0.59.0",
 ]
 
+[[package]]
+name = "termcolor"
+version = "1.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "06794f8f6c5c898b3275aebefa6b8a1cb24cd2c6c79397ab15774837a0bc5755"
+dependencies = [
+ "winapi-util",
+]
+
+[[package]]
+name = "textwrap"
+version = "0.16.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "23d434d3f8967a09480fb04132ebe0a3e088c173e6d0ee7897abbdf4eab0f8b9"
+
 [[package]]
 name = "thiserror"
 version = "1.0.63"
@@ -1833,6 +1936,15 @@ dependencies = [
  "tokio",
 ]
 
+[[package]]
+name = "toml"
+version = "0.5.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f4f7f0dd8d50a853a531c426359045b1998f04219d88799810762cd4ad314234"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "toml_datetime"
 version = "0.6.8"

Cargo.toml

@@ -62,6 +62,8 @@ serde = { version = "1.0", features = ["derive"], optional = true }
 napi-build = { version = "2.1", optional = true }
 # glue (python)
 pyo3-build-config = { version = "0.22", optional = true }
+# glue (C)
+cbindgen = { version = "0.24", optional = true }
 
 [features]
 default = []
@@ -73,6 +75,7 @@ java = ["lazy_static", "jni", "tracing-subscriber", "jni-toolbox"]
 js = ["napi-build", "tracing-subscriber", "napi", "napi-derive"]
 py-noabi = ["pyo3", "tracing-subscriber", "pyo3-build-config"]
 py = ["py-noabi", "pyo3/abi3-py38"]
+c = ["cbindgen"]
 lua = ["mlua-codemp-patch", "tracing-subscriber", "lazy_static", "serialize"]
 lua54 =["lua", "mlua-codemp-patch/lua54"] 
 luajit = ["lua", "mlua-codemp-patch/luajit"]

build.rs

@@ -4,6 +4,9 @@ extern crate napi_build;
 #[cfg(any(feature = "py", feature = "py-noabi"))]
 extern crate pyo3_build_config;
 
+#[cfg(feature = "c")]
+extern crate cbindgen;
+
 /// The main method of the buildscript, required by some glue modules.
 fn main() {
 	#[cfg(feature = "js")]
@@ -20,7 +23,16 @@ fn main() {
 	{
 		if let Ok("macos") = std::env::var("CARGO_CFG_TARGET_OS").as_deref() {
 			println!("cargo:rustc-cdylib-link-arg=-undefined");
-  		println!("cargo:rustc-cdylib-link-arg=dynamic_lookup");
+			println!("cargo:rustc-cdylib-link-arg=dynamic_lookup");
-  	}
+		}
+	}
+
+	#[cfg(feature = "c")]
+	{
+		cbindgen::Builder::new()
+			.with_crate(std::env::var("CARGO_MANIFEST_DIR").unwrap())
+			.generate()
+			.expect("Unable to generate bindings")
+			.write_to_file("dist/c/codemp.h");
 	}
 }

dist/c/codemp.h

@@ -0,0 +1,28 @@
+#include <cstdarg>
+#include <cstdint>
+#include <cstdlib>
+#include <ostream>
+#include <new>
+
+/// A `codemp` client handle.
+///
+/// It generates a new UUID and stores user credentials upon connecting.
+///
+/// A new [`Client`] can be obtained with [`Client::connect`].
+struct Client;
+
+/// A currently active shared development environment
+///
+/// Workspaces encapsulate a working environment: cursor positions, filetree, user list
+/// and more. Each holds a [cursor::Controller] and a map of [buffer::Controller]s.
+/// Using a workspace handle, it's possible to receive events (user join/leave, filetree updates)
+/// and create/delete/attach to new buffers.
+struct Workspace;
+
+extern "C" {
+
+Client *Codemp_Client_connect();
+
+Workspace *Codemp_Client_join_workspace(Client *client, char *workspace);
+
+} // extern "C"

src/ffi/c/mod.rs

@@ -0,0 +1,45 @@
+use std::ffi::{c_char, CString};
+
+use crate::{api::Config, Client, Workspace};
+
+pub(crate) fn tokio() -> &'static tokio::runtime::Runtime {
+	use std::sync::OnceLock;
+	static RT: OnceLock<tokio::runtime::Runtime> = OnceLock::new();
+	RT.get_or_init(||
+		tokio::runtime::Builder::new_current_thread()
+			.enable_all()
+			.build()
+			.expect("could not create tokio runtime")
+	)
+}
+
+
+#[no_mangle] // TODO config
+pub extern "C" fn Codemp_Client_connect() -> *mut Client {
+	match tokio()
+		.block_on(Client::connect(Config::new("", "")))
+	{
+		Ok(c) => Box::into_raw(Box::new(c)),
+		Err(e) => {
+			tracing::error!("failed connecting to remote: {e}");
+			std::ptr::null_mut()
+		},
+	}
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn Codemp_Client_join_workspace(client: *mut Client, workspace: *mut c_char) -> *mut Workspace {
+	let client = unsafe { Box::leak(Box::from_raw(client)) };
+	let workspace = unsafe { CString::from_raw(workspace) }.to_string_lossy().to_string();
+
+	match tokio()
+		.block_on(client.join_workspace(workspace))
+	{
+		Ok(ws) => Box::into_raw(Box::new(ws)),
+		Err(e) => {
+			tracing::error!("failed joining workspace: {e}");
+			std::ptr::null_mut()
+		},
+	}
+
+}

src/ffi/mod.rs

@@ -58,3 +58,7 @@ pub mod js;
 /// python bindings, built with [pyo3]
 #[cfg(any(feature = "py", feature = "py-noabi"))]
 pub mod python;
+
+/// c bindings, generated with [cbindgen]
+#[cfg(feature = "c")]
+pub mod c;