Implement ability to timeout execution of a regexp

src/org/joni/ByteCodeMachine.java

@@ -176,6 +176,7 @@ private final int execute(final boolean checkThreadInterrupt) throws Interrupted
         int interruptCheckCounter = 0;
         while (true) {
             if (interruptCheckCounter++ >= interruptCheckEvery) {
+                if (timeout != -1) handleTimeout();
                 handleInterrupted(checkThreadInterrupt);
                 interruptCheckCounter = 0;
             }
@@ -306,11 +307,16 @@ private final int execute(final boolean checkThreadInterrupt) throws Interrupted
         } // main while
     }
 
+    private void handleTimeout() throws InterruptedException {
+        if (System.nanoTime() - startTime > timeout) throw TIMEOUT_EXCEPTION;
+    }
+
     private final int executeSb(final boolean checkThreadInterrupt) throws InterruptedException {
         final int[] code = this.code;
         int interruptCheckCounter = 0;
         while (true) {
             if (interruptCheckCounter++ >= interruptCheckEvery) {
+                if (timeout != -1) handleTimeout();
                 handleInterrupted(checkThreadInterrupt);
                 interruptCheckCounter = 0;
             }
@@ -447,7 +453,7 @@ private final int executeSb(final boolean checkThreadInterrupt) throws Interrupt
     private void handleInterrupted(final boolean checkThreadInterrupt) throws InterruptedException {
         if (interrupted || (checkThreadInterrupt && Thread.currentThread().isInterrupted())) {
             Thread.interrupted();
-            throw new InterruptedException();
+            throw INTERRUPTED_EXCEPTION;
         }
         interruptCheckEvery = Math.min(interruptCheckEvery << 1, MAX_INTERRUPT_CHECK_EVERY);
     }

src/org/joni/Matcher.java

@@ -27,8 +27,11 @@
 import org.jcodings.constants.CharacterType;
 import org.jcodings.specific.ASCIIEncoding;
 import org.joni.constants.internal.AnchorType;
+import org.joni.exception.TimeoutException;
 
 public abstract class Matcher extends IntHolder {
+    static final InterruptedException INTERRUPTED_EXCEPTION = new InterruptedException();
+    static final InterruptedException TIMEOUT_EXCEPTION = new TimeoutException();
     public static final int FAILED = -1;
     public static final int INTERRUPTED = -2;
 
@@ -49,13 +52,26 @@ public abstract class Matcher extends IntHolder {
     protected int msaBegin;
     protected int msaEnd;
 
+    protected long timeout;  // nanoseconds
+
+    // nanoseconds since entering searchCommon (underlying machines will check during interrupt checks
+    // which will cheapen how often we look but also it should be granular enough to not matter).
+    protected long startTime;
+
     Matcher(Regex regex, Region region, byte[]bytes, int p, int end) {
+        this(regex, region, bytes, p, end, -1);
+    }
+
+    // FIXME: For next major version this should be the main constructor and MatcherFactory should
+    // have the abstract method be for this.
+    Matcher(Regex regex, Region region, byte[]bytes, int p, int end, long timeout) {
         this.regex = regex;
         this.enc = regex.enc;
         this.bytes = bytes;
         this.str = p;
         this.end = end;
         this.msaRegion = region;
+        this.timeout = timeout;
     }
 
     // main matching method
@@ -323,6 +339,7 @@ public final int searchInterruptible(int gpos, int start, int range, int option)
     }
 
     private final int searchCommon(int gpos, int start, int range, int option, boolean interrupt) throws InterruptedException {
+        if (timeout != -1) startTime = System.nanoTime();
         int s, prev;
         int origStart = start;
         int origRange = range;
@@ -640,4 +657,7 @@ static void debugSearch(String name, int textP, int textEnd, int textRange) {
         Config.log.println(name + ": text: " + textP + ", text_end: " + textEnd + ", text_range: " + textRange);
     }
 
+    public void setTimeout(long timeout) {
+        this.timeout = timeout;
+    }
 }

src/org/joni/MatcherFactory.java

@@ -22,6 +22,12 @@
 abstract class MatcherFactory {
     abstract Matcher create(Regex regex, Region region, byte[]bytes, int p, int end);
 
+    public Matcher create(Regex regex, Region region, byte[]bytes, int p, int end, long timeout) {
+        Matcher matcher = create(regex, region, bytes, p, end);
+        matcher.setTimeout(timeout);
+        return matcher;
+    }
+
     static final MatcherFactory DEFAULT = new MatcherFactory() {
         @Override
         Matcher create(Regex regex, Region region, byte[]bytes, int p, int end) {

src/org/joni/Regex.java

@@ -185,10 +185,18 @@ public Matcher matcher(byte[]bytes, int p, int end) {
         return factory.create(this, numMem == 0 ? null : Region.newRegion(numMem + 1), bytes, p, end);
     }
 
+    public Matcher matcher(byte[]bytes, int p, int end, long timeout) {
+        return factory.create(this, numMem == 0 ? null : Region.newRegion(numMem + 1), bytes, p, end, timeout);
+    }
+
     public Matcher matcherNoRegion(byte[]bytes, int p, int end) {
         return factory.create(this, null, bytes, p, end);
     }
 
+    public Matcher matcherNoRegion(byte[]bytes, int p, int end, long timeout) {
+        return factory.create(this, null, bytes, p, end, timeout);
+    }
+
     public int numberOfCaptures() {
         return numMem;
     }

src/org/joni/exception/TimeoutException.java

@@ -0,0 +1,7 @@
+package org.joni.exception;
+
+public class TimeoutException extends InterruptedException {
+    public TimeoutException() {
+        super();
+    }
+}