thermostat/src/session.rs

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2020-03-14 06:39:22 +08:00
use super::command_parser::{Command, Error as ParserError};
const MAX_LINE_LEN: usize = 64;
struct LineReader {
buf: [u8; MAX_LINE_LEN],
pos: usize,
}
impl LineReader {
pub fn new() -> Self {
LineReader {
buf: [0; MAX_LINE_LEN],
pos: 0,
}
}
pub fn feed(&mut self, c: u8) -> Option<&[u8]> {
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if c == 13 || c == 10 {
// Enter
if self.pos > 0 {
let len = self.pos;
self.pos = 0;
Some(&self.buf[..len])
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} else {
None
}
} else if self.pos < self.buf.len() {
// Add input
self.buf[self.pos] = c;
self.pos += 1;
None
} else {
// Buffer is full, ignore
None
}
}
}
pub enum SessionOutput {
Nothing,
Command(Command),
Error(ParserError),
}
impl From<Result<Command, ParserError>> for SessionOutput {
fn from(input: Result<Command, ParserError>) -> Self {
input.map(SessionOutput::Command)
.unwrap_or_else(SessionOutput::Error)
}
}
pub const CHANNELS: usize = 2;
pub struct Session {
reader: LineReader,
reporting: bool,
report_pending: [bool; CHANNELS],
}
impl Default for Session {
fn default() -> Self {
Session::new()
}
}
impl Session {
pub fn new() -> Self {
Session {
reader: LineReader::new(),
reporting: false,
report_pending: [false; CHANNELS],
}
}
pub fn reset(&mut self) {
self.reader = LineReader::new();
self.reporting = false;
self.report_pending = [false; CHANNELS];
}
pub fn is_dirty(&self) -> bool {
self.reader.pos > 0
}
pub fn reporting(&self) -> bool {
self.reporting
}
pub fn set_report_pending(&mut self, channel: usize) {
if self.reporting {
self.report_pending[channel] = true;
}
}
pub fn is_report_pending(&self) -> Option<usize> {
if ! self.reporting {
None
} else {
self.report_pending.iter()
.enumerate()
.fold(None, |result, (channel, report_pending)| {
result.or_else(|| {
if *report_pending { Some(channel) } else { None }
})
})
}
}
pub fn mark_report_sent(&mut self, channel: usize) {
self.report_pending[channel] = false;
}
pub fn feed(&mut self, buf: &[u8]) -> (usize, SessionOutput) {
let mut buf_bytes = 0;
for (i, b) in buf.iter().enumerate() {
buf_bytes = i + 1;
let line = self.reader.feed(*b);
match line {
Some(line) => {
let command = Command::parse(&line);
match command {
Ok(Command::Reporting(reporting)) => {
self.reporting = reporting;
}
_ => {}
}
return (buf_bytes, command.into());
}
None => {}
}
}
(buf_bytes, SessionOutput::Nothing)
}
}