feat: Add target.rs module for sending data blocks related functions

Author: IshanGrover2004

src/rust/lib_ccxr/src/net/target.rs

@@ -0,0 +1,293 @@
+use super::{
+    block::{Block, BlockStream, Command, DEFAULT_TCP_PORT, NO_RESPONSE_INTERVAL, PING_INTERVAL},
+    NetError,
+};
+use crate::time::units::Timestamp;
+use crate::util::log::{fatal, info, ExitCause};
+
+use std::io;
+use std::io::{Read, Write};
+use std::net::TcpStream;
+
+/// A struct of configuration parameters to construct [`SendTarget`].
+#[derive(Copy, Clone, Debug)]
+pub struct SendTargetConfig<'a> {
+    /// Target's IP address or hostname.
+    pub target_addr: &'a str,
+
+    /// Target's port number.
+    ///
+    /// If no port number is provided then [`DEFAULT_TCP_PORT`] will be used instead.
+    pub port: Option<u16>,
+
+    /// Password to be sent after establishing connection.
+    pub password: Option<&'a str>,
+
+    /// Description to sent after establishing connection.
+    pub description: Option<&'a str>,
+}
+
+/// A struct used for sending subtitle data across the network.
+///
+/// Even though it exposes methods from [`BlockStream`], it is recommended to not use them.
+/// Instead use the methods provided directly by [`SendTarget`] like [`SendTarget::send_header`],
+/// [`SendTarget::send_cc`], etc.
+///
+/// To create a [`SendTarget`], one must first construct a [`SendTargetConfig`].
+///
+/// ```no_run
+/// # use lib_ccxr::net::{SendTarget, SendTargetConfig};
+/// let config = SendTargetConfig {
+///     target_addr: "192.168.60.133",
+///     port: None,
+///     password: Some("12345678"),
+///     description: None,
+/// };
+/// let mut send_target = SendTarget::new(config);
+///
+/// // Once send_target is constructed, we can use it to send different kinds of data.
+/// # let header = &[0u8; 1];
+/// send_target.send_header(header);
+/// # let cc = &[0u8; 1];
+/// send_target.send_cc(cc);
+/// ```
+pub struct SendTarget<'a> {
+    stream: Option<TcpStream>,
+    config: SendTargetConfig<'a>,
+    header_data: Option<Vec<u8>>,
+    last_ping: Timestamp,
+    last_send_ping: Timestamp,
+}
+
+impl BlockStream for SendTarget<'_> {
+    fn send(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.stream.as_mut().unwrap().write(buf)
+    }
+
+    fn recv(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        self.stream.as_mut().unwrap().read(buf)
+    }
+}
+
+impl<'a> SendTarget<'a> {
+    /// Create a new [`SendTarget`] from the configuration parameters of [`SendTargetConfig`].
+    ///
+    /// Note: This method attempts to connect to a server. It does not return a [`Result`]. When
+    /// it is unable to connect to a server, it crashes instantly by calling [`fatal!`].
+    pub fn new(config: SendTargetConfig<'a>) -> SendTarget<'a> {
+        if config.target_addr.is_empty() {
+            info!("Server address is not set\n");
+            fatal!(
+                cause = ExitCause::Failure;
+                "Unable to connect, address passed is null\n"
+            );
+        }
+
+        let tcp_stream = TcpStream::connect((
+            config.target_addr,
+            config.port.unwrap_or(DEFAULT_TCP_PORT),
+        ))
+        .unwrap_or_else(
+            |_| fatal!(cause = ExitCause::Failure; "Unable to connect (tcp connection error).\n"),
+        );
+
+        tcp_stream.set_nonblocking(true).unwrap_or_else(
+            |_| fatal!(cause = ExitCause::Failure; "Unable to connect (set nonblocking).\n"),
+        );
+
+        let mut send_target = SendTarget {
+            stream: Some(tcp_stream),
+            config,
+            header_data: None,
+            last_ping: Timestamp::from_millis(0),
+            last_send_ping: Timestamp::from_millis(0),
+        };
+
+        send_target.send_password().unwrap_or_else(
+            |_| fatal!(cause = ExitCause::Failure; "Unable to connect (sending password).\n"),
+        );
+
+        send_target.send_description().unwrap_or_else(
+            |_| fatal!(cause = ExitCause::Failure; "Unable to connect (sending cc_desc).\n"),
+        );
+
+        info!(
+            "Connected to {}:{}\n",
+            send_target.config.target_addr,
+            send_target.config.port.unwrap_or_else(|| DEFAULT_TCP_PORT)
+        );
+
+        send_target
+    }
+
+    /// Consumes the [`SendTarget`] only returning its internal stream.
+    ///
+    /// Note: Crashes if `self.stream` is not set.
+    fn into_stream(self) -> TcpStream {
+        self.stream.expect("TcpStream must be set")
+    }
+
+    /// Send a [`BinHeader`](Command::BinHeader) [`Block`] returning if the operation was successful.
+    pub fn send_header(&mut self, data: &[u8]) -> bool {
+        #[cfg(feature = "debug_out")]
+        {
+            eprintln!("Sending header (len = {}): ", data.len());
+            eprintln!(
+                "File created by {:02X} version {:02X}{:02X}",
+                data[3], data[4], data[5]
+            );
+            eprintln!("File format revision: {:02X}{:02X}", data[6], data[7]);
+        }
+
+        if let Ok(true) = self.send_block(&Block::bin_header(data)) {
+        } else {
+            println!("Can't send BIN header");
+            return false;
+        }
+
+        if self.header_data.is_none() {
+            self.header_data = Some(data.into())
+        }
+
+        true
+    }
+
+    /// Send a [`BinData`](Command::BinData) [`Block`] returning if the operation was successful.
+    pub fn send_cc(&mut self, data: &[u8]) -> bool {
+        #[cfg(feature = "debug_out")]
+        {
+            eprintln!("[C] Sending {} bytes", data.len());
+        }
+
+        if let Ok(true) = self.send_block(&Block::bin_data(data)) {
+        } else {
+            println!("Can't send BIN data");
+            return false;
+        }
+
+        true
+    }
+
+    /// Send a [`EpgData`](Command::EpgData) [`Block`] returning if the operation was successful.
+    pub fn send_epg_data(
+        &mut self,
+        start: &str,
+        stop: &str,
+        title: Option<&str>,
+        desc: Option<&str>,
+        lang: Option<&str>,
+        category: Option<&str>,
+    ) -> bool {
+        let block = Block::epg_data(start, stop, title, desc, lang, category);
+
+        #[cfg(feature = "debug_out")]
+        {
+            eprintln!("[C] Sending EPG: {} bytes", block.data().len())
+        }
+
+        if let Ok(true) = self.send_block(&block) {
+        } else {
+            eprintln!("Can't send EPG data");
+            return false;
+        }
+
+        true
+    }
+
+    /// Send a [`Ping`](Command::Ping) [`Block`].
+    ///
+    /// It returns a [`NetError`] if some transmission failure ocurred, or else it will return a bool
+    /// that indicates the status of this connection. It will be `false` if the connection shutdown
+    /// correctly.
+    fn send_ping(&mut self) -> Result<bool, NetError> {
+        self.send_block(&Block::ping())
+    }
+
+    /// Send a [`Password`](Command::Password) [`Block`].
+    ///
+    /// It returns a [`NetError`] if some transmission failure ocurred, or else it will return a bool
+    /// that indicates the status of this connection. It will be `false` if the connection shutdown
+    /// correctly.
+    fn send_password(&mut self) -> Result<bool, NetError> {
+        let password = self.config.password.unwrap_or("");
+        self.send_block(&Block::password(password))
+    }
+
+    /// Send a [`CcDesc`](Command::CcDesc) [`Block`].
+    ///
+    /// It returns a [`NetError`] if some transmission failure ocurred, or else it will return a bool
+    /// that indicates the status of this connection. It will be `false` if the connection shutdown
+    /// correctly.
+    fn send_description(&mut self) -> Result<bool, NetError> {
+        let description = self.config.description.unwrap_or("");
+        self.send_block(&Block::cc_desc(description))
+    }
+
+    /// Check the connection health and reset connection if necessary.
+    ///
+    /// This method determines the connection health by comparing the time since last [`Ping`]
+    /// [`Block`] was received with [`NO_RESPONSE_INTERVAL`]. If it exceeds the
+    /// [`NO_RESPONSE_INTERVAL`], the connection is reset.
+    ///
+    /// This method also sends timely [`Ping`] [`Block`]s back to the server based on the
+    /// [`PING_INTERVAL`]. This method will crash instantly with [`fatal!`] if it is unable to send
+    /// data.
+    ///
+    /// [`Ping`]: Command::Ping
+    pub fn check_connection(&mut self) {
+        let now = Timestamp::now();
+
+        if self.last_ping.millis() == 0 {
+            self.last_ping = now;
+        }
+
+        loop {
+            if self
+                .recv_block()
+                .ok()
+                .flatten()
+                .map(|x| x.command() == Command::Ping)
+                .unwrap_or(false)
+            {
+                #[cfg(feature = "debug_out")]
+                {
+                    eprintln!("[S] Received PING");
+                }
+                self.last_ping = now;
+            } else {
+                break;
+            }
+        }
+
+        if now - self.last_ping > NO_RESPONSE_INTERVAL {
+            eprintln!(
+                "[S] No PING received from the server in {} sec, reconnecting",
+                NO_RESPONSE_INTERVAL.seconds()
+            );
+
+            self.stream
+                .take()
+                .unwrap()
+                .shutdown(std::net::Shutdown::Both)
+                .expect("Unable to shutdown the TCP Server");
+
+            self.stream = Some(SendTarget::new(self.config).into_stream());
+
+            // `self.header_data` is only temporarily taken, since it will be refilled inside
+            // `send_header` function.
+            if let Some(header_data) = self.header_data.take() {
+                self.send_header(header_data.as_slice());
+            }
+
+            self.last_ping = now;
+        }
+
+        if now - self.last_send_ping >= PING_INTERVAL {
+            if self.send_ping().is_err() {
+                fatal!(cause = ExitCause::Failure; "Unable to send data\n");
+            }
+
+            self.last_send_ping = now;
+        }
+    }
+}