Port l2cap_bridge sample to Rust

- Added Rust wrappers where relevant
- Edited a couple logs in python l2cap_bridge to be more symmetrical
- Created cli subcommand for running the rustified l2cap bridge

rust/src/wrapper/device.rs

@@ -19,16 +19,17 @@ use crate::{
     wrapper::{
         core::AdvertisingData,
         gatt_client::{ProfileServiceProxy, ServiceProxy},
-        hci::Address,
+        hci::{Address, HciErrorCode},
         host::Host,
+        l2cap::LeConnectionOrientedChannel,
         transport::{Sink, Source},
-        ClosureCallback, PyObjectExt,
+        ClosureCallback, PyDictExt, PyObjectExt,
     },
 };
 use pyo3::{
     intern,
     types::{PyDict, PyModule},
-    PyObject, PyResult, Python, ToPyObject,
+    IntoPy, PyObject, PyResult, Python, ToPyObject,
 };
 use pyo3_asyncio::tokio::into_future;
 use std::path;
@@ -87,6 +88,22 @@ impl Device {
         .map(Connection)
     }
 
+    /// Register a callback to be called for each incoming connection.
+    pub fn on_connection(
+        &mut self,
+        callback: impl Fn(Python, Connection) -> PyResult<()> + Send + 'static,
+    ) -> PyResult<()> {
+        let boxed = ClosureCallback::new(move |py, args, _kwargs| {
+            callback(py, Connection(args.get_item(0)?.into()))
+        });
+
+        Python::with_gil(|py| {
+            self.0
+                .call_method1(py, intern!(py, "add_listener"), ("connection", boxed))
+        })
+        .map(|_| ())
+    }
+
     /// Start scanning
     pub async fn start_scanning(&self, filter_duplicates: bool) -> PyResult<()> {
         Python::with_gil(|py| {
@@ -161,11 +178,109 @@ impl Device {
         .await
         .map(|_| ())
     }
+
+    /// Registers an L2CAP connection oriented channel server. When a client connects to the server,
+    /// the `server` callback returns a handle to the established channel. When optional arguments
+    /// are not specified, the Python module specifies the defaults.
+    pub fn register_l2cap_channel_server(
+        &self,
+        psm: u16,
+        server: impl Fn(Python, LeConnectionOrientedChannel) -> PyResult<()> + Send + 'static,
+        max_credits: Option<u16>,
+        mtu: Option<u16>,
+        mps: Option<u16>,
+    ) -> PyResult<()> {
+        Python::with_gil(|py| {
+            let boxed = ClosureCallback::new(move |py, args, _kwargs| {
+                server(
+                    py,
+                    LeConnectionOrientedChannel::from(args.get_item(0)?.into()),
+                )
+            });
+
+            let kwargs = PyDict::new(py);
+            kwargs.set_item("psm", psm)?;
+            kwargs.set_item("server", boxed.into_py(py))?;
+            kwargs.set_opt_item("max_credits", max_credits)?;
+            kwargs.set_opt_item("mtu", mtu)?;
+            kwargs.set_opt_item("mps", mps)?;
+            self.0.call_method(
+                py,
+                intern!(py, "register_l2cap_channel_server"),
+                (),
+                Some(kwargs),
+            )
+        })?;
+        Ok(())
+    }
 }
 
 /// A connection to a remote device.
 pub struct Connection(PyObject);
 
+impl Connection {
+    /// Open an L2CAP channel using this connection. When optional arguments are not specified, the
+    /// Python module specifies the defaults.
+    pub async fn open_l2cap_channel(
+        &self,
+        psm: u16,
+        max_credits: Option<u16>,
+        mtu: Option<u16>,
+        mps: Option<u16>,
+    ) -> PyResult<LeConnectionOrientedChannel> {
+        Python::with_gil(|py| {
+            let kwargs = PyDict::new(py);
+            kwargs.set_item("psm", psm)?;
+            kwargs.set_opt_item("max_credits", max_credits)?;
+            kwargs.set_opt_item("mtu", mtu)?;
+            kwargs.set_opt_item("mps", mps)?;
+            self.0
+                .call_method(py, intern!(py, "open_l2cap_channel"), (), Some(kwargs))
+                .and_then(|coroutine| pyo3_asyncio::tokio::into_future(coroutine.as_ref(py)))
+        })?
+        .await
+        .map(LeConnectionOrientedChannel::from)
+    }
+
+    /// Disconnect from device with provided reason. When optional arguments are not specified, the
+    /// Python module specifies the defaults.
+    pub async fn disconnect(self, reason: Option<HciErrorCode>) -> PyResult<()> {
+        Python::with_gil(|py| {
+            let kwargs = PyDict::new(py);
+            kwargs.set_opt_item("reason", reason)?;
+            self.0
+                .call_method(py, intern!(py, "disconnect"), (), Some(kwargs))
+                .and_then(|coroutine| pyo3_asyncio::tokio::into_future(coroutine.as_ref(py)))
+        })?
+        .await
+        .map(|_| ())
+    }
+
+    /// Register a callback to be called on disconnection.
+    pub fn on_disconnection(
+        &mut self,
+        callback: impl Fn(Python, HciErrorCode) -> PyResult<()> + Send + 'static,
+    ) -> PyResult<()> {
+        let boxed = ClosureCallback::new(move |py, args, _kwargs| {
+            callback(py, args.get_item(0)?.extract()?)
+        });
+
+        Python::with_gil(|py| {
+            self.0
+                .call_method1(py, intern!(py, "add_listener"), ("disconnection", boxed))
+        })
+        .map(|_| ())
+    }
+
+    /// Returns some information about the connection as a [String].
+    pub fn debug_string(&self) -> PyResult<String> {
+        Python::with_gil(|py| {
+            let str_obj = self.0.call_method0(py, intern!(py, "__str__"))?;
+            str_obj.gil_ref(py).extract()
+        })
+    }
+}
+
 /// The other end of a connection
 pub struct Peer(PyObject);
 

rust/src/wrapper/hci.rs

@@ -15,7 +15,40 @@
 //! HCI
 
 use itertools::Itertools as _;
-use pyo3::{exceptions::PyException, intern, types::PyModule, PyErr, PyObject, PyResult, Python};
+use pyo3::{
+    exceptions::PyException, intern, types::PyModule, FromPyObject, PyAny, PyErr, PyObject,
+    PyResult, Python, ToPyObject,
+};
+
+/// HCI error code.
+pub struct HciErrorCode(u8);
+
+impl<'source> FromPyObject<'source> for HciErrorCode {
+    fn extract(ob: &'source PyAny) -> PyResult<Self> {
+        Ok(HciErrorCode(ob.extract()?))
+    }
+}
+
+impl ToPyObject for HciErrorCode {
+    fn to_object(&self, py: Python<'_>) -> PyObject {
+        self.0.to_object(py)
+    }
+}
+
+/// Provides helpers for interacting with HCI
+pub struct HciConstant;
+
+impl HciConstant {
+    /// Human-readable error name
+    pub fn error_name(status: HciErrorCode) -> PyResult<String> {
+        Python::with_gil(|py| {
+            PyModule::import(py, intern!(py, "bumble.hci"))?
+                .getattr(intern!(py, "HCI_Constant"))?
+                .call_method1(intern!(py, "error_name"), (status.0,))?
+                .extract()
+        })
+    }
+}
 
 /// A Bluetooth address
 pub struct Address(pub(crate) PyObject);

rust/src/wrapper/l2cap.rs

@@ -0,0 +1,92 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! L2CAP
+
+use crate::wrapper::{ClosureCallback, PyObjectExt};
+use pyo3::{intern, PyObject, PyResult, Python};
+
+/// L2CAP connection-oriented channel
+pub struct LeConnectionOrientedChannel(PyObject);
+
+impl LeConnectionOrientedChannel {
+    /// Create a LeConnectionOrientedChannel that wraps the provided obj.
+    pub(crate) fn from(obj: PyObject) -> Self {
+        Self(obj)
+    }
+
+    /// Queues data to be automatically sent across this channel.
+    pub fn write(&mut self, data: &[u8]) -> PyResult<()> {
+        Python::with_gil(|py| self.0.call_method1(py, intern!(py, "write"), (data,))).map(|_| ())
+    }
+
+    /// Wait for queued data to be sent on this channel.
+    pub async fn drain(&self) -> PyResult<()> {
+        Python::with_gil(|py| {
+            self.0
+                .call_method0(py, intern!(py, "drain"))
+                .and_then(|coroutine| pyo3_asyncio::tokio::into_future(coroutine.as_ref(py)))
+        })?
+        .await
+        .map(|_| ())
+    }
+
+    /// Register a callback to be called when the channel is closed.
+    pub fn on_close(
+        &mut self,
+        callback: impl Fn(Python) -> PyResult<()> + Send + 'static,
+    ) -> PyResult<()> {
+        let boxed = ClosureCallback::new(move |py, _args, _kwargs| callback(py));
+
+        Python::with_gil(|py| {
+            self.0
+                .call_method1(py, intern!(py, "add_listener"), ("close", boxed))
+        })
+        .map(|_| ())
+    }
+
+    /// Register a callback to be called when the channel receives data.
+    pub fn set_sink(
+        &mut self,
+        callback: impl Fn(Python, &[u8]) -> PyResult<()> + Send + 'static,
+    ) -> PyResult<()> {
+        let boxed = ClosureCallback::new(move |py, args, _kwargs| {
+            callback(py, args.get_item(0)?.extract()?)
+        });
+        Python::with_gil(|py| self.0.setattr(py, intern!(py, "sink"), boxed)).map(|_| ())
+    }
+
+    /// Disconnect the l2cap channel.
+    /// Must be called from a thread with a Python event loop, which should be true on
+    /// `tokio::main` and `async_std::main`.
+    ///
+    /// For more info, see https://awestlake87.github.io/pyo3-asyncio/master/doc/pyo3_asyncio/#event-loop-references-and-contextvars.
+    pub async fn disconnect(self) -> PyResult<()> {
+        Python::with_gil(|py| {
+            self.0
+                .call_method0(py, intern!(py, "disconnect"))
+                .and_then(|coroutine| pyo3_asyncio::tokio::into_future(coroutine.as_ref(py)))
+        })?
+        .await
+        .map(|_| ())
+    }
+
+    /// Returns some information about the channel as a [String].
+    pub fn debug_string(&self) -> PyResult<String> {
+        Python::with_gil(|py| {
+            let str_obj = self.0.call_method0(py, intern!(py, "__str__"))?;
+            str_obj.gil_ref(py).extract()
+        })
+    }
+}

rust/src/wrapper/mod.rs

@@ -31,11 +31,11 @@ pub use pyo3_asyncio;
 pub mod assigned_numbers;
 pub mod core;
 pub mod device;
-
 pub mod drivers;
 pub mod gatt_client;
 pub mod hci;
 pub mod host;
+pub mod l2cap;
 pub mod logging;
 pub mod profile;
 pub mod transport;
@@ -71,6 +71,21 @@ impl PyObjectExt for PyObject {
     }
 }
 
+/// Convenience extensions to [PyDict]
+pub trait PyDictExt {
+    /// Set item in dict only if value is Some, otherwise do nothing.
+    fn set_opt_item<K: ToPyObject, V: ToPyObject>(&self, key: K, value: Option<V>) -> PyResult<()>;
+}
+
+impl PyDictExt for PyDict {
+    fn set_opt_item<K: ToPyObject, V: ToPyObject>(&self, key: K, value: Option<V>) -> PyResult<()> {
+        if let Some(value) = value {
+            self.set_item(key, value)?
+        }
+        Ok(())
+    }
+}
+
 /// Wrapper to make Rust closures ([Fn] implementations) callable from Python.
 ///
 /// The Python callable form returns a Python `None`.