feat: phase 3 — framebuffer, raw decoder, session pump, snapshot
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framebuffer.rs:
- Framebuffer struct (8bpp RGB332, row-major)
- apply_raw() blit, copy_rect() with overlap-safe logic
- to_rgba() via compile-time RGB332 LUT

session.rs:
- ActiveSession: connect + SetEncodings + initial FBUpdateRequest
- Full server message dispatch loop (all 15 message types)
- Raw (encoding 0) and CopyRect (encoding 1) decoders
- Ping response, bandwidth probe bookends, mode change resize

examples/snapshot.rs:
- Connects, waits for first FramebufferUpdate, saves PNG
- Tested against real OmniView at 10.3.0.130:443
- Successfully captured 640x480 frame

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This commit is contained in:
2026-05-06 14:23:43 +03:00
parent 1bd43fc1f9
commit e9823aff03
7 changed files with 485 additions and 5 deletions

View File

@@ -0,0 +1,203 @@
use std::io::{BufReader, BufWriter};
use std::net::TcpStream;
use crate::framebuffer::Framebuffer;
use crate::handshake::{self, Config, ServerInit};
use crate::msg::{self, ServerMsg};
use crate::proto::{self, RectHeader, read_exact, read_u8};
#[derive(Debug, thiserror::Error)]
pub enum SessionError {
#[error("handshake: {0}")]
Handshake(#[from] handshake::HandshakeError),
#[error("protocol: {0}")]
Proto(#[from] proto::ProtoError),
#[error("io: {0}")]
Io(#[from] std::io::Error),
#[error("unsupported encoding: {0}")]
UnsupportedEncoding(i32),
#[error("unsupported message type: {0}")]
UnsupportedMessage(u8),
}
/// Events emitted by the session pump to consumers.
#[derive(Debug)]
pub enum Event {
/// A region of the framebuffer was updated.
FramebufferDirty,
/// The framebuffer was resized.
Resize { width: u16, height: u16 },
/// Bell from server.
Bell,
/// Server sent a debug string.
Debug(String),
/// Server sent an RFB command (key, value).
RfbCommand(String, String),
/// Server name updated.
NameUpdate(String),
}
/// Active protocol session with framebuffer.
pub struct ActiveSession {
pub framebuffer: Framebuffer,
pub server_name: String,
pub reader: BufReader<TcpStream>,
pub writer: BufWriter<TcpStream>,
pub server_init: ServerInit,
}
impl ActiveSession {
/// Connect, handshake, send SetEncodings + initial FBUpdateRequest.
pub fn connect(cfg: &Config, encodings: &[i32]) -> Result<Self, SessionError> {
let raw = handshake::connect(cfg)?;
let mut session = Self {
framebuffer: Framebuffer::new(raw.server_init.width, raw.server_init.height),
server_name: raw.server_name,
reader: raw.reader,
writer: raw.writer,
server_init: raw.server_init,
};
// Send SetEncodings
msg::write_set_encodings(&mut session.writer, encodings)?;
// Request full non-incremental framebuffer update
msg::write_fb_update_request(
&mut session.writer,
0,
0,
session.framebuffer.width,
session.framebuffer.height,
false,
)?;
Ok(session)
}
/// Request an incremental framebuffer update.
pub fn request_update(&mut self) -> Result<(), SessionError> {
msg::write_fb_update_request(
&mut self.writer,
0,
0,
self.framebuffer.width,
self.framebuffer.height,
true,
)?;
Ok(())
}
/// Process one server message. Returns an event if meaningful to the consumer.
pub fn process_one(&mut self) -> Result<Option<Event>, SessionError> {
let msg_type = read_u8(&mut self.reader)?;
let msg = ServerMsg::from(msg_type);
match msg {
ServerMsg::FramebufferUpdate => {
self.handle_fb_update()?;
Ok(Some(Event::FramebufferDirty))
}
ServerMsg::Bell => Ok(Some(Event::Bell)),
ServerMsg::Ping => {
let payload = msg::read_ping(&mut self.reader)?;
msg::write_ping_response(&mut self.writer, payload)?;
Ok(None)
}
ServerMsg::BandwidthProbe => {
msg::write_bandwidth_marker(&mut self.writer, 1)?;
msg::read_bandwidth_probe(&mut self.reader)?;
msg::write_bandwidth_marker(&mut self.writer, 2)?;
Ok(None)
}
ServerMsg::Ack => {
msg::read_ack(&mut self.reader)?;
Ok(None)
}
ServerMsg::DebugString => {
let s = msg::read_debug_string(&mut self.reader)?;
Ok(Some(Event::Debug(s)))
}
ServerMsg::RfbCommand => {
let (k, v) = msg::read_rfb_command(&mut self.reader)?;
Ok(Some(Event::RfbCommand(k, v)))
}
ServerMsg::ServerCutText => {
let _text = msg::read_server_cut_text(&mut self.reader)?;
Ok(None)
}
ServerMsg::ServerNameUpdate => {
let name = msg::read_server_name_update(&mut self.reader)?;
self.server_name = name.clone();
Ok(Some(Event::NameUpdate(name)))
}
ServerMsg::LayoutLocale => {
let _locale = msg::read_layout_locale(&mut self.reader)?;
Ok(None)
}
ServerMsg::DesktopResize => {
// Reads same struct as handshake pixel-format (aw.i, line 519)
let _flag = read_u8(&mut self.reader)?;
let _depth = proto::read_u16_be(&mut self.reader)?;
let label_len = proto::read_u16_be(&mut self.reader)? as usize;
let _label = read_exact(&mut self.reader, label_len)?;
Ok(None)
}
ServerMsg::ModeChange => {
// Re-read ServerInit (aw.k, line 435) — framebuffer dimensions may change
let si = handshake::read_server_init_from(&mut self.reader)?;
let old_w = self.framebuffer.width;
let old_h = self.framebuffer.height;
self.server_init = si;
if self.server_init.width != old_w || self.server_init.height != old_h {
self.framebuffer
.resize(self.server_init.width, self.server_init.height);
return Ok(Some(Event::Resize {
width: self.server_init.width,
height: self.server_init.height,
}));
}
Ok(None)
}
ServerMsg::RdpEvent => {
let _event_type = msg::read_rdp_event(&mut self.reader)?;
Ok(None)
}
ServerMsg::PixelFormatChange => {
// aw.e(), line 537: 1 pad + 4×u8 + 8×u16 = 21 bytes
let _data = read_exact(&mut self.reader, 21)?;
Ok(None)
}
ServerMsg::SetColourMapEntries => Err(SessionError::UnsupportedMessage(msg_type)),
ServerMsg::Unknown(t) => Err(SessionError::UnsupportedMessage(t)),
}
}
fn handle_fb_update(&mut self) -> Result<(), SessionError> {
let num_rects = msg::read_fb_update_header(&mut self.reader)?;
for _ in 0..num_rects {
let hdr = RectHeader::read_from(&mut self.reader)?;
match hdr.encoding {
0 => {
// Raw: read w*h bytes
let size = hdr.w as usize * hdr.h as usize;
let data = read_exact(&mut self.reader, size)?;
self.framebuffer
.apply_raw(hdr.x, hdr.y, hdr.w, hdr.h, &data);
}
1 => {
// CopyRect: read src_x, src_y (u16 each)
let src_x = proto::read_u16_be(&mut self.reader)?;
let src_y = proto::read_u16_be(&mut self.reader)?;
self.framebuffer
.copy_rect(src_x, src_y, hdr.x, hdr.y, hdr.w, hdr.h);
}
other => {
return Err(SessionError::UnsupportedEncoding(other));
}
}
}
Ok(())
}
}