| 1 | package jagi.event; |
| 2 | |
| 3 | import java.util.*; |
| 4 | import java.util.logging.*; |
| 5 | import java.util.concurrent.*; |
| 6 | import java.io.*; |
| 7 | import java.nio.*; |
| 8 | import java.nio.channels.*; |
| 9 | import java.nio.channels.spi.*; |
| 10 | |
| 11 | public class Driver { |
| 12 | private static final Logger log = Logger.getLogger("jagi.event"); |
| 13 | private static final Logger hlog = Logger.getLogger("jagi.event.handler"); |
| 14 | private static final ThreadLocal<Driver> current = new ThreadLocal<>(); |
| 15 | private final Map<SelectorProvider, SelectPool> selectors = new HashMap<>(); |
| 16 | private final ExecutorService worker = new ThreadPoolExecutor(0, Runtime.getRuntime().availableProcessors(), |
| 17 | 5, TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>(128), |
| 18 | this::thread); |
| 19 | |
| 20 | protected Thread thread(Runnable tgt) { |
| 21 | return(new Thread(tgt)); |
| 22 | } |
| 23 | |
| 24 | protected void handle(Watcher w, int evs) { |
| 25 | try { |
| 26 | current.set(this); |
| 27 | w.handle(evs); |
| 28 | } catch(Throwable t) { |
| 29 | error(w, t, "handling event"); |
| 30 | } finally { |
| 31 | current.remove(); |
| 32 | } |
| 33 | } |
| 34 | |
| 35 | protected void close(Watcher w) { |
| 36 | try { |
| 37 | current.set(this); |
| 38 | w.close(); |
| 39 | } catch(Throwable t) { |
| 40 | error(w, t, "closing"); |
| 41 | } finally { |
| 42 | current.remove(); |
| 43 | } |
| 44 | } |
| 45 | |
| 46 | protected void submit(Runnable task) { |
| 47 | worker.submit(task); |
| 48 | } |
| 49 | |
| 50 | protected void error(Watcher w, Throwable t, String thing) { |
| 51 | hlog.log(Level.WARNING, w + ": uncaught error when " + thing, t); |
| 52 | remove(w); |
| 53 | } |
| 54 | |
| 55 | class SelectPool implements Runnable { |
| 56 | final SelectorProvider provider; |
| 57 | final Selector poll; |
| 58 | final Map<Watcher, SelectionKey> watching = new IdentityHashMap<>(); |
| 59 | final Heap<Watcher, Double> timeheap = new Heap<>(Comparator.naturalOrder()); |
| 60 | final Map<Watcher, Object> paused = new IdentityHashMap<>(); |
| 61 | final Collection<SelectionKey> cancelled = new HashSet<>(); |
| 62 | |
| 63 | SelectPool(SelectorProvider provider) { |
| 64 | this.provider = provider; |
| 65 | try { |
| 66 | this.poll = provider.openSelector(); |
| 67 | } catch(IOException e) { |
| 68 | /* I think this counts more as an assertion error. */ |
| 69 | throw(new RuntimeException(e)); |
| 70 | } |
| 71 | } |
| 72 | |
| 73 | void handle(Watcher w, int evs) { |
| 74 | if(!watching.containsKey(w)) |
| 75 | return; |
| 76 | try { |
| 77 | pause(w); |
| 78 | submit(() -> { |
| 79 | try { |
| 80 | Driver.this.handle(w, evs); |
| 81 | } finally { |
| 82 | resume(w); |
| 83 | } |
| 84 | }); |
| 85 | } catch(Throwable t) { |
| 86 | try { |
| 87 | synchronized(selectors) { |
| 88 | remove(w); |
| 89 | } |
| 90 | } catch(Exception e) { |
| 91 | t.addSuppressed(e); |
| 92 | } |
| 93 | log.log(Level.SEVERE, "unexpected error when submitting event", t); |
| 94 | } |
| 95 | } |
| 96 | |
| 97 | void start() { |
| 98 | thread(this).start(); |
| 99 | } |
| 100 | |
| 101 | public void run() { |
| 102 | boolean quit = false; |
| 103 | Throwable error = null; |
| 104 | try { |
| 105 | double now = time(); |
| 106 | while(true) { |
| 107 | long timeout = 0; |
| 108 | synchronized(selectors) { |
| 109 | Double first = timeheap.keypeek(); |
| 110 | if((first == null) && watching.isEmpty()) { |
| 111 | quit = true; |
| 112 | selectors.remove(provider); |
| 113 | return; |
| 114 | } |
| 115 | if(first != null) |
| 116 | timeout = Math.max((long)Math.ceil((first - now) * 1000), 1); |
| 117 | } |
| 118 | Collection<SelectionKey> precancelled; |
| 119 | synchronized(cancelled) { |
| 120 | precancelled = new ArrayList<>(cancelled); |
| 121 | } |
| 122 | if(!precancelled.isEmpty()) |
| 123 | timeout = 1; |
| 124 | poll.selectedKeys().clear(); |
| 125 | try { |
| 126 | poll.select(timeout); |
| 127 | } catch(IOException e) { |
| 128 | throw(new RuntimeException(e)); |
| 129 | } |
| 130 | if(!precancelled.isEmpty()) { |
| 131 | synchronized(cancelled) { |
| 132 | cancelled.removeAll(precancelled); |
| 133 | cancelled.notifyAll(); |
| 134 | } |
| 135 | } |
| 136 | for(SelectionKey key : poll.selectedKeys()) |
| 137 | handle((Watcher)key.attachment(), key.readyOps()); |
| 138 | now = time(); |
| 139 | while(true) { |
| 140 | Double first = timeheap.keypeek(); |
| 141 | if((first == null) || (first > now)) |
| 142 | break; |
| 143 | handle(timeheap.remove(), 0); |
| 144 | } |
| 145 | } |
| 146 | } catch(Throwable t) { |
| 147 | error = t; |
| 148 | throw(t); |
| 149 | } finally { |
| 150 | if(!quit) |
| 151 | log.log(Level.SEVERE, "selector exited abnormally", error); |
| 152 | } |
| 153 | } |
| 154 | |
| 155 | void pause(Watcher w) { |
| 156 | if(paused.containsKey(w)) |
| 157 | throw(new IllegalStateException(w + ": already paused")); |
| 158 | SelectionKey wc = watching.get(w); |
| 159 | Object tc = timeheap.remove(w); |
| 160 | if((wc == null) && (tc == null)) |
| 161 | throw(new IllegalStateException(w + ": not registered")); |
| 162 | if(wc != null) |
| 163 | wc.interestOps(0); |
| 164 | paused.put(w, this); |
| 165 | } |
| 166 | |
| 167 | void resume(Watcher w) { |
| 168 | if(paused.remove(w) == null) |
| 169 | return; |
| 170 | SelectionKey wc = watching.get(w); |
| 171 | int evs = w.events(); |
| 172 | double timeout = w.timeout(); |
| 173 | boolean hastime = timeout < Double.POSITIVE_INFINITY; |
| 174 | if(evs < 0) { |
| 175 | remove(w); |
| 176 | return; |
| 177 | } |
| 178 | wc.interestOps(evs); |
| 179 | if(hastime) |
| 180 | timeheap.add(w, timeout); |
| 181 | poll.wakeup(); |
| 182 | } |
| 183 | |
| 184 | void add(Watcher w, SelectableChannel ch) { |
| 185 | if(watching.containsKey(w) || paused.containsKey(w) || timeheap.contains(w)) |
| 186 | throw(new IllegalStateException(w + ": already registered")); |
| 187 | try { |
| 188 | ch.configureBlocking(false); |
| 189 | } catch(IOException e) { |
| 190 | throw(new RuntimeException(ch + ": could not make non-blocking", e)); |
| 191 | } |
| 192 | int evs = w.events(); |
| 193 | double timeout = w.timeout(); |
| 194 | boolean hastime = timeout < Double.POSITIVE_INFINITY; |
| 195 | if(evs < 0) { |
| 196 | submit(() -> close(w)); |
| 197 | return; |
| 198 | } |
| 199 | w.added(Driver.this); |
| 200 | try { |
| 201 | watching.put(w, ch.register(poll, evs, w)); |
| 202 | } catch(ClosedChannelException e) { |
| 203 | throw(new RuntimeException("attempted to watch closed channel", e)); |
| 204 | } |
| 205 | if(hastime) |
| 206 | timeheap.add(w, timeout); |
| 207 | poll.wakeup(); |
| 208 | } |
| 209 | |
| 210 | void remove(Watcher w) { |
| 211 | SelectionKey wc = watching.remove(w); |
| 212 | Object tc = timeheap.remove(w); |
| 213 | Object pc = paused.remove(w); |
| 214 | if(wc != null) { |
| 215 | synchronized(cancelled) { |
| 216 | cancelled.add(wc); |
| 217 | wc.cancel(); |
| 218 | poll.wakeup(); |
| 219 | boolean irq = false; |
| 220 | while(cancelled.contains(wc)) { |
| 221 | try { |
| 222 | cancelled.wait(); |
| 223 | } catch(InterruptedException e) { |
| 224 | irq = true; |
| 225 | } |
| 226 | } |
| 227 | if(irq) |
| 228 | Thread.currentThread().interrupt(); |
| 229 | } |
| 230 | } |
| 231 | if(((wc != null) || (tc != null)) && (pc != null)) |
| 232 | throw(new RuntimeException(w + ": inconsistent internal state")); |
| 233 | if(wc == null) |
| 234 | throw(new IllegalStateException(w + ": not registered")); |
| 235 | submit(() -> close(w)); |
| 236 | } |
| 237 | |
| 238 | void update(Watcher w) { |
| 239 | SelectionKey wc = watching.get(w); |
| 240 | if(wc == null) |
| 241 | throw(new IllegalStateException(w + ": not registered")); |
| 242 | int evs = w.events(); |
| 243 | double timeout = w.timeout(); |
| 244 | boolean hastime = timeout < Double.POSITIVE_INFINITY; |
| 245 | if(evs < 0) { |
| 246 | remove(w); |
| 247 | return; |
| 248 | } |
| 249 | wc.interestOps(evs); |
| 250 | if(hastime) |
| 251 | timeheap.set(w, timeout); |
| 252 | else |
| 253 | timeheap.remove(w); |
| 254 | poll.wakeup(); |
| 255 | } |
| 256 | } |
| 257 | |
| 258 | private SelectPool pool(SelectorProvider provider) { |
| 259 | SelectPool pool = selectors.get(provider); |
| 260 | if(pool == null) { |
| 261 | pool = new SelectPool(provider); |
| 262 | selectors.put(provider, pool); |
| 263 | pool.start(); |
| 264 | } |
| 265 | return(pool); |
| 266 | } |
| 267 | |
| 268 | public void add(Watcher w) { |
| 269 | SelectableChannel ch = w.channel(); |
| 270 | synchronized(selectors) { |
| 271 | pool(ch.provider()).add(w, ch); |
| 272 | } |
| 273 | } |
| 274 | |
| 275 | public void remove(Watcher w) { |
| 276 | SelectableChannel ch = w.channel(); |
| 277 | synchronized(selectors) { |
| 278 | pool(ch.provider()).remove(w); |
| 279 | } |
| 280 | } |
| 281 | |
| 282 | public void update(Watcher w) { |
| 283 | SelectableChannel ch = w.channel(); |
| 284 | synchronized(selectors) { |
| 285 | pool(ch.provider()).update(w); |
| 286 | } |
| 287 | } |
| 288 | |
| 289 | public double time() { |
| 290 | return(rtime()); |
| 291 | } |
| 292 | |
| 293 | private static final long rtimeoff = System.nanoTime(); |
| 294 | public static double rtime() { |
| 295 | return((System.nanoTime() - rtimeoff) / 1e9); |
| 296 | } |
| 297 | |
| 298 | private static Driver global = null; |
| 299 | public static Driver get() { |
| 300 | if(global == null) { |
| 301 | synchronized(Driver.class) { |
| 302 | if(global == null) |
| 303 | global = new Driver(); |
| 304 | } |
| 305 | } |
| 306 | return(global); |
| 307 | } |
| 308 | |
| 309 | public static Driver current() { |
| 310 | Driver ret = current.get(); |
| 311 | if(ret == null) |
| 312 | throw(new IllegalStateException("no current driver")); |
| 313 | return(ret); |
| 314 | } |
| 315 | } |