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| 1 | +use std::borrow::Cow; |
| 2 | +use std::env::args; |
| 3 | +use std::fmt::Write; |
| 4 | +use std::io::ErrorKind; |
| 5 | +use std::net::SocketAddr; |
| 6 | +use std::process::exit; |
| 7 | +use std::string::String; |
| 8 | +use std::sync::Arc; |
| 9 | +use std::time::Duration; |
| 10 | +use std::vec::Vec; |
| 11 | +use std::{eprintln, format}; |
| 12 | + |
| 13 | +use linkme::distributed_slice; |
| 14 | +use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader}; |
| 15 | +use tokio::net::TcpStream; |
| 16 | +use tokio::net::tcp::{OwnedReadHalf, OwnedWriteHalf}; |
| 17 | +use tokio::spawn; |
| 18 | +use tokio::sync::{Mutex, oneshot}; |
| 19 | + |
| 20 | +use super::{DYNAMIC_ENVIRON_KEY, MainRequest, MainResponse, Outcome}; |
| 21 | + |
| 22 | +const PROCESSORS: usize = 4; |
| 23 | + |
| 24 | +#[inline(never)] |
| 25 | +pub(crate) fn run_dynamic_main() { |
| 26 | + std::env::set_var(DYNAMIC_ENVIRON_KEY, "-"); |
| 27 | + |
| 28 | + let mut entries: Vec<_> = DYNAMIC_TEMPLATES.iter().map(|entry| entry.name()).collect(); |
| 29 | + entries.sort_unstable(); |
| 30 | + eprintln!("templates implemented by subprocess: {entries:?}"); |
| 31 | + for window in entries.windows(2) { |
| 32 | + if let &[a, b] = window { |
| 33 | + if a == b { |
| 34 | + eprintln!("duplicated dynamic template {a:?}"); |
| 35 | + } |
| 36 | + } |
| 37 | + } |
| 38 | + |
| 39 | + let sock_addr: SocketAddr = { |
| 40 | + let mut args = args().fuse(); |
| 41 | + let (_, Some("--__rinja_dynamic"), Some(sock_addr), None) = ( |
| 42 | + args.next(), |
| 43 | + args.next().as_deref(), |
| 44 | + args.next(), |
| 45 | + args.next(), |
| 46 | + ) else { |
| 47 | + eprintln!("child process got unexpected arguments"); |
| 48 | + exit(1); |
| 49 | + }; |
| 50 | + match serde_json::from_str(&sock_addr) { |
| 51 | + Ok(sock_addr) => sock_addr, |
| 52 | + Err(err) => { |
| 53 | + eprintln!("subprocess could not interpret socket addr: {err}"); |
| 54 | + exit(1); |
| 55 | + } |
| 56 | + } |
| 57 | + }; |
| 58 | + |
| 59 | + let rt = match tokio::runtime::Builder::new_current_thread() |
| 60 | + .enable_all() |
| 61 | + .build() |
| 62 | + { |
| 63 | + Ok(rt) => rt, |
| 64 | + Err(err) => { |
| 65 | + eprintln!("could not start tokio runtime: {err}"); |
| 66 | + exit(1); |
| 67 | + } |
| 68 | + }; |
| 69 | + let _ = rt.block_on(async move { |
| 70 | + let sock = match TcpStream::connect(sock_addr).await { |
| 71 | + Ok(sock) => sock, |
| 72 | + Err(err) => { |
| 73 | + eprintln!("subprocess could not connect to parent process: {err}"); |
| 74 | + exit(1); |
| 75 | + } |
| 76 | + }; |
| 77 | + let _: Result<(), std::io::Error> = sock.set_linger(None); |
| 78 | + let _: Result<(), std::io::Error> = sock.set_nodelay(true); |
| 79 | + let (read, write) = sock.into_split(); |
| 80 | + |
| 81 | + let stdout = Arc::new(Mutex::new(write)); |
| 82 | + let stdin = Arc::new(Mutex::new(BufReader::new(read))); |
| 83 | + let (done_tx, done_rx) = oneshot::channel(); |
| 84 | + let done = Arc::new(Mutex::new(Some(done_tx))); |
| 85 | + |
| 86 | + let mut threads = Vec::with_capacity(PROCESSORS); |
| 87 | + for _ in 0..PROCESSORS { |
| 88 | + threads.push(spawn(dynamic_processor( |
| 89 | + Arc::clone(&stdout), |
| 90 | + Arc::clone(&stdin), |
| 91 | + Arc::clone(&done), |
| 92 | + ))); |
| 93 | + } |
| 94 | + |
| 95 | + done_rx.await.map_err(|err| { |
| 96 | + std::io::Error::new(ErrorKind::BrokenPipe, format!("lost result channel: {err}")); |
| 97 | + }) |
| 98 | + }); |
| 99 | + rt.shutdown_timeout(Duration::from_secs(5)); |
| 100 | + exit(0) |
| 101 | +} |
| 102 | + |
| 103 | +async fn dynamic_processor( |
| 104 | + stdout: Arc<Mutex<OwnedWriteHalf>>, |
| 105 | + stdin: Arc<Mutex<BufReader<OwnedReadHalf>>>, |
| 106 | + done: Arc<Mutex<Option<oneshot::Sender<std::io::Result<()>>>>>, |
| 107 | +) { |
| 108 | + let done = move |result: Result<(), std::io::Error>| { |
| 109 | + let done = Arc::clone(&done); |
| 110 | + async move { |
| 111 | + let mut lock = done.lock().await; |
| 112 | + if let Some(done) = lock.take() { |
| 113 | + let _: Result<_, _> = done.send(result); |
| 114 | + } |
| 115 | + } |
| 116 | + }; |
| 117 | + |
| 118 | + let mut line_buf = String::new(); |
| 119 | + let mut response_buf = String::new(); |
| 120 | + loop { |
| 121 | + line_buf.clear(); |
| 122 | + match stdin.lock().await.read_line(&mut line_buf).await { |
| 123 | + Ok(n) if n > 0 => {} |
| 124 | + result => return done(result.map(|_| ())).await, |
| 125 | + } |
| 126 | + let line = line_buf.trim_ascii(); |
| 127 | + if line.is_empty() { |
| 128 | + continue; |
| 129 | + } |
| 130 | + |
| 131 | + let MainRequest { callid, name, data } = match serde_json::from_str(line) { |
| 132 | + Ok(req) => req, |
| 133 | + Err(err) => { |
| 134 | + let err = format!("could not deserialize request: {err}"); |
| 135 | + return done(Err(std::io::Error::new(ErrorKind::InvalidData, err))).await; |
| 136 | + } |
| 137 | + }; |
| 138 | + response_buf.clear(); |
| 139 | + |
| 140 | + let mut outcome = Outcome::NotFound; |
| 141 | + for entry in DYNAMIC_TEMPLATES { |
| 142 | + if entry.name() == name { |
| 143 | + outcome = entry.dynamic_render(&mut response_buf, &data); |
| 144 | + break; |
| 145 | + } |
| 146 | + } |
| 147 | + |
| 148 | + // SAFETY: `serde_json` writes valid UTF-8 data |
| 149 | + let mut line = unsafe { line_buf.as_mut_vec() }; |
| 150 | + |
| 151 | + line.clear(); |
| 152 | + if let Err(err) = serde_json::to_writer(&mut line, &MainResponse { callid, outcome }) { |
| 153 | + let err = format!("could not serialize response: {err}"); |
| 154 | + return done(Err(std::io::Error::new(ErrorKind::InvalidData, err))).await; |
| 155 | + } |
| 156 | + line.push(b'\n'); |
| 157 | + |
| 158 | + let is_done = { |
| 159 | + let mut stdout = stdout.lock().await; |
| 160 | + stdout.write_all(line).await.is_err() || stdout.flush().await.is_err() |
| 161 | + }; |
| 162 | + if is_done { |
| 163 | + return done(Ok(())).await; |
| 164 | + } |
| 165 | + } |
| 166 | +} |
| 167 | + |
| 168 | +/// Used by [`Template`][rinja_derive::Template] to register a template for dynamic processing. |
| 169 | +#[macro_export] |
| 170 | +macro_rules! register_dynamic_template { |
| 171 | + ( |
| 172 | + name: $Name:ty, |
| 173 | + type: $Type:ty, |
| 174 | + ) => { |
| 175 | + const _: () = { |
| 176 | + #[$crate::helpers::linkme::distributed_slice($crate::helpers::DYNAMIC_TEMPLATES)] |
| 177 | + #[linkme(crate = $crate::helpers::linkme)] |
| 178 | + static DYNAMIC_TEMPLATES: &'static dyn $crate::helpers::DynamicTemplate = &Dynamic; |
| 179 | + |
| 180 | + struct Dynamic; |
| 181 | + |
| 182 | + impl $crate::helpers::DynamicTemplate for Dynamic { |
| 183 | + #[inline] |
| 184 | + fn name(&self) -> &$crate::helpers::core::primitive::str { |
| 185 | + $crate::helpers::core::any::type_name::<$Name>() |
| 186 | + } |
| 187 | + |
| 188 | + fn dynamic_render<'a>( |
| 189 | + &self, |
| 190 | + buf: &'a mut rinja::helpers::alloc::string::String, |
| 191 | + value: &rinja::helpers::core::primitive::str, |
| 192 | + ) -> rinja::helpers::Outcome<'a> { |
| 193 | + let result = rinja::helpers::from_json::<$Type>(value).map(|tmpl| { |
| 194 | + buf.clear(); |
| 195 | + let _ = buf.try_reserve(<Tmpl as $crate::Template>::SIZE_HINT); |
| 196 | + tmpl.render_into(buf) |
| 197 | + }); |
| 198 | + $crate::helpers::use_dynamic_render_result(buf, result) |
| 199 | + } |
| 200 | + } |
| 201 | + }; |
| 202 | + }; |
| 203 | +} |
| 204 | + |
| 205 | +/// Convert the result of [`serde::from_json()`] → [`Template::render()`] to an [`Outcome`]. |
| 206 | +pub fn use_dynamic_render_result( |
| 207 | + buf: &mut String, |
| 208 | + result: Result<Result<(), crate::Error>, serde_json::Error>, |
| 209 | +) -> Outcome<'_> { |
| 210 | + let result = match &result { |
| 211 | + Ok(Ok(())) => return Outcome::Success(Cow::Borrowed(buf)), |
| 212 | + Ok(Err(err)) => Ok(err), |
| 213 | + Err(err) => Err(err), |
| 214 | + }; |
| 215 | + |
| 216 | + buf.clear(); |
| 217 | + let result = match result { |
| 218 | + Ok(e) => write!(buf, "{e}").map(|_| Outcome::Render(Cow::Borrowed(buf))), |
| 219 | + Err(e) => write!(buf, "{e}").map(|_| Outcome::Deserialize(Cow::Borrowed(buf))), |
| 220 | + }; |
| 221 | + result.unwrap_or(Outcome::Fmt) |
| 222 | +} |
| 223 | + |
| 224 | +/// List of implemented dynamic templates. Filled through |
| 225 | +/// [`register_dynamic_template!`][crate::register_dynamic_template]. |
| 226 | +#[distributed_slice] |
| 227 | +pub static DYNAMIC_TEMPLATES: [&'static dyn DynamicTemplate]; |
| 228 | + |
| 229 | +/// A dynamic template implementation |
| 230 | +pub trait DynamicTemplate: Send + Sync { |
| 231 | + /// The type name of the template. |
| 232 | + fn name(&self) -> &str; |
| 233 | + |
| 234 | + /// Take a JSON `value` to to render the template into `buf`. |
| 235 | + fn dynamic_render<'a>(&self, buf: &'a mut String, value: &str) -> Outcome<'a>; |
| 236 | +} |
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