libosdp: Update to latest version and rework channel API

Signed-off-by: Siddharth Chandrasekaran <sidcha.dev@gmail.com>

libosdp/Cargo.toml

@@ -14,20 +14,17 @@ categories = ["development-tools", "embedded"]
 
 [dependencies]
 bitflags = "2.4.0"
-embedded-io = "0.6.1"
-libosdp-sys = "0.1.5"
+libosdp-sys = "3.0.2"
 log = "0.4.20"
-multiqueue = "0.3.2"
 once_cell = "1.18.0"
-parking_lot = { version = "0.12.1", optional = true }
-ringbuf = "0.3.3"
 serde = { version = "1.0.192", features = ["derive"] }
-spin = "0.9.8"
 thiserror = { version = "1.0.50", optional = true }
 
 [dev-dependencies]
 env_logger = "0.10.0"
+multiqueue = "0.3.2"
+ringbuf = "0.3.3"
 
 [features]
 default = ["std"]
-std = ["thiserror", "parking_lot"]
+std = ["thiserror"]

libosdp/examples/cp.rs

@@ -4,31 +4,62 @@
 // SPDX-License-Identifier: Apache-2.0
 
 use libosdp::{
-    channel::{OsdpChannel, UnixChannel},
-    ControlPanel, OsdpError, OsdpFlag, PdInfo,
+    OsdpError, OsdpFlag, PdInfo, Channel, ChannelError,
 };
-use std::{result::Result, thread, time::Duration, path::PathBuf, str::FromStr};
+use std::{env, thread, time::Duration};
+
+struct OsdpChannel;
+
+impl OsdpChannel {
+    fn new(_path: &str) -> Self {
+        // setup device
+        Self {
+        }
+    }
+}
+
+/// Read documentation for each member in [libosdp::Channel].
+impl Channel for OsdpChannel {
+    fn get_id(&self) -> i32 {
+        0
+    }
+
+    fn read(&mut self, _buf: &mut [u8]) -> Result<usize, ChannelError> {
+        // TODO: Read from device
+        Ok(0)
+    }
+
+    fn write(&mut self, buf: &[u8]) -> Result<usize, ChannelError> {
+        // TODO: Write from device
+        Ok(buf.len())
+    }
+
+    fn flush(&mut self) -> Result<(), ChannelError> {
+        // TODO: flush device
+        Ok(())
+    }
+}
 
 fn main() -> Result<(), OsdpError> {
     env_logger::builder()
         .filter_level(log::LevelFilter::Info)
         .format_target(false)
         .format_timestamp(None)
         .init();
-    let path = PathBuf::from_str("/tmp/conn-1")?;
-    let stream = UnixChannel::connect(&path)?;
+    let args: Vec<String> = env::args().collect();
+    let channel = OsdpChannel::new(&args[1]);
     let pd_info = vec![PdInfo::for_cp(
         "PD 101",
         101,
         115200,
         OsdpFlag::EnforceSecure,
-        OsdpChannel::new::<UnixChannel>(Box::new(stream)),
+        Box::new(channel),
         [
             0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d,
             0x0e, 0x0f,
         ],
     )];
-    let mut cp = ControlPanel::new(pd_info)?;
+    let mut cp = libosdp::ControlPanel::new(pd_info)?;
     loop {
         cp.refresh();
         thread::sleep(Duration::from_millis(50));

libosdp/examples/pd.rs

@@ -4,33 +4,64 @@
 // SPDX-License-Identifier: Apache-2.0
 
 use libosdp::{
-    channel::{OsdpChannel, UnixChannel},
-    OsdpError, OsdpFlag, PdCapEntity, PdCapability, PdId, PdInfo, PeripheralDevice,
+    Channel, ChannelError, OsdpError, OsdpFlag, PdCapEntity, PdCapability, PdId, PdInfo,
 };
-use std::{result::Result, thread, time::Duration, path::PathBuf, str::FromStr};
+use std::{thread, time::Duration};
+
+struct OsdpChannel;
+
+impl OsdpChannel {
+    pub fn new(_path: &str) -> Self {
+        // setup device
+        Self {
+        }
+    }
+}
+
+/// Read documentation for each member in [libosdp::Channel].
+impl Channel for OsdpChannel {
+    fn get_id(&self) -> i32 {
+        0
+    }
+
+    fn read(&mut self, _buf: &mut [u8]) -> Result<usize, ChannelError> {
+        // TODO: Read from device
+        Ok(0)
+    }
+
+    fn write(&mut self, buf: &[u8]) -> Result<usize, ChannelError> {
+        // TODO: Write from device
+        Ok(buf.len())
+    }
+
+    fn flush(&mut self) -> Result<(), ChannelError> {
+        // TODO: flush device
+        Ok(())
+    }
+}
 
 fn main() -> Result<(), OsdpError> {
     env_logger::builder()
         .filter_level(log::LevelFilter::Info)
         .format_target(false)
         .format_timestamp(None)
         .init();
-    let path = PathBuf::from_str("/tmp/conn-1")?;
-    let stream = UnixChannel::new(&path)?;
+    let args: Vec<String> = std::env::args().collect();
+    let channel = OsdpChannel::new(&args[1]);
     let pd_info = PdInfo::for_pd(
         "PD 101",
         101,
         115200,
         OsdpFlag::EnforceSecure,
         PdId::from_number(101),
         vec![PdCapability::CommunicationSecurity(PdCapEntity::new(1, 1))],
-        OsdpChannel::new::<UnixChannel>(Box::new(stream)),
+        Box::new(channel),
         [
             0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d,
             0x0e, 0x0f,
         ],
     );
-    let mut pd = PeripheralDevice::new(pd_info)?;
+    let mut pd = libosdp::PeripheralDevice::new(pd_info)?;
     pd.set_command_callback(|_| {
         println!("Received command!");
         0

libosdp/src/channel.rs

@@ -0,0 +1,67 @@
+//
+// Copyright (c) 2023-2024 Siddharth Chandrasekaran <sidcha.dev@gmail.com>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+//! The OSDP specification defines that communication between OSDP devices
+//! happen over an RS-485 connection. For testing and development purpose this
+//! can be limiting so LibOSDP defines a notion called "Channel" which is a
+//! software representation (abstraction) of the physical transport medium.
+//!
+//! Since RS-485 is stream based protocol, we can think of it to be  something
+//! that we can read from and write to (which in turn is Read and Write traits
+//! in rust). This allows us to run OSDP devices over many IPC schemes such as
+//! Unix socket and message queues.
+//!
+//! This module provides a way to define an OSDP channel and export it to
+//! LibOSDP.
+
+/// OSDP channel errors
+#[derive(Clone, Debug)]
+pub enum ChannelError {
+    /// Channel is temporarily unavailable (could have blocked until it was
+    /// ready but LibOSDP required channel to be non-blocking so return "I would
+    /// have blocked" instead)
+    WouldBlock,
+    /// Channel failed irrecoverably. 
+    TransportError,
+}
+
+impl From<std::io::Error> for ChannelError {
+    fn from(value: std::io::Error) -> Self {
+        match value.kind() {
+            std::io::ErrorKind::WouldBlock => ChannelError::WouldBlock,
+            _ => ChannelError::TransportError,
+        }
+    }
+}
+
+/// The Channel trait acts as an interface for all channel implementors. See
+/// module description for the definition of a "channel" in LibOSDP.
+pub trait Channel: Send + Sync {
+    /// Since OSDP channels can be multi-drop (more than one PD can talk to a
+    /// CP on the same channel) and LibOSDP supports mixing multi-drop
+    /// connections among PDs it needs a way to identify each unique channel by
+    /// a channel ID. Implementors of this trait must also provide a method
+    /// which returns a unique i32 per channel.
+    fn get_id(&self) -> i32;
+
+    /// Pull as many bytes into buffer as possible; returns the number of bytes
+    /// were read.
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize, ChannelError>;
+
+    /// Write a buffer into this writer, returning how many bytes were written.
+    fn write(&mut self, buf: &[u8]) -> Result<usize, ChannelError>;
+
+    /// Flush this output stream, ensuring that all intermediately buffered
+    /// contents reach their destination.
+    fn flush(&mut self) -> Result<(), ChannelError>;
+}
+
+impl core::fmt::Debug for dyn Channel {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        f.debug_struct("Channel")
+            .field("id", &self.get_id())
+            .finish()
+    }
+}