| 10 |
|
/** |
| 11 |
|
* A package-local class holding common representation and mechanics |
| 12 |
|
* for classes supporting dynamic striping on 64bit values. The class |
| 13 |
< |
* extends Number so that concrete subclasses can publicly do so. |
| 13 |
> |
* extends Number so that concrete subclasses must publicly do so. |
| 14 |
|
*/ |
| 15 |
|
abstract class Striped64 extends Number { |
| 16 |
|
/* |
| 40 |
|
* |
| 41 |
|
* A single spinlock ("busy") is used for initializing and |
| 42 |
|
* resizing the table, as well as populating slots with new Cells. |
| 43 |
< |
* There is no need for a blocking lock: When the lock is not |
| 43 |
> |
* There is no need for a blocking lock; when the lock is not |
| 44 |
|
* available, threads try other slots (or the base). During these |
| 45 |
|
* retries, there is increased contention and reduced locality, |
| 46 |
|
* which is still better than alternatives. |
| 77 |
|
*/ |
| 78 |
|
|
| 79 |
|
/** |
| 80 |
< |
* Padded variant of AtomicLong supporting only raw accesses plus |
| 81 |
< |
* CAS The value field is placed between pads, hoping that the JVM |
| 82 |
< |
* doesn't reorder them. |
| 80 |
> |
* Padded variant of AtomicLong supporting only raw accesses plus CAS. |
| 81 |
> |
* The value field is placed between pads, hoping that the JVM doesn't |
| 82 |
> |
* reorder them. |
| 83 |
|
* |
| 84 |
|
* JVM intrinsics note: It would be possible to use a release-only |
| 85 |
|
* form of CAS here, if it were provided. |
| 164 |
|
} |
| 165 |
|
|
| 166 |
|
/** |
| 167 |
< |
* CAS the base field |
| 167 |
> |
* CASes the base field. |
| 168 |
|
*/ |
| 169 |
|
final boolean casBase(long cmp, long val) { |
| 170 |
|
return UNSAFE.compareAndSwapLong(this, baseOffset, cmp, val); |
| 171 |
|
} |
| 172 |
|
|
| 173 |
|
/** |
| 174 |
< |
* CAS the busy field from 0 to 1 to acquire lock. |
| 174 |
> |
* CASes the busy field from 0 to 1 to acquire lock. |
| 175 |
|
*/ |
| 176 |
|
final boolean casBusy() { |
| 177 |
|
return UNSAFE.compareAndSwapInt(this, busyOffset, 0, 1); |
| 277 |
|
|
| 278 |
|
|
| 279 |
|
/** |
| 280 |
< |
* Set base and all cells to the given value |
| 280 |
> |
* Sets base and all cells to the given value. |
| 281 |
|
*/ |
| 282 |
|
final void internalReset(long initialValue) { |
| 283 |
|
Cell[] as = cells; |
| 319 |
|
private static sun.misc.Unsafe getUnsafe() { |
| 320 |
|
try { |
| 321 |
|
return sun.misc.Unsafe.getUnsafe(); |
| 322 |
< |
} catch (SecurityException se) { |
| 323 |
< |
try { |
| 324 |
< |
return java.security.AccessController.doPrivileged |
| 325 |
< |
(new java.security |
| 326 |
< |
.PrivilegedExceptionAction<sun.misc.Unsafe>() { |
| 327 |
< |
public sun.misc.Unsafe run() throws Exception { |
| 328 |
< |
java.lang.reflect.Field f = sun.misc |
| 329 |
< |
.Unsafe.class.getDeclaredField("theUnsafe"); |
| 330 |
< |
f.setAccessible(true); |
| 331 |
< |
return (sun.misc.Unsafe) f.get(null); |
| 332 |
< |
}}); |
| 333 |
< |
} catch (java.security.PrivilegedActionException e) { |
| 334 |
< |
throw new RuntimeException("Could not initialize intrinsics", |
| 335 |
< |
e.getCause()); |
| 336 |
< |
} |
| 322 |
> |
} catch (SecurityException tryReflectionInstead) {} |
| 323 |
> |
try { |
| 324 |
> |
return java.security.AccessController.doPrivileged |
| 325 |
> |
(new java.security.PrivilegedExceptionAction<sun.misc.Unsafe>() { |
| 326 |
> |
public sun.misc.Unsafe run() throws Exception { |
| 327 |
> |
Class<sun.misc.Unsafe> k = sun.misc.Unsafe.class; |
| 328 |
> |
for (java.lang.reflect.Field f : k.getDeclaredFields()) { |
| 329 |
> |
f.setAccessible(true); |
| 330 |
> |
Object x = f.get(null); |
| 331 |
> |
if (k.isInstance(x)) |
| 332 |
> |
return k.cast(x); |
| 333 |
> |
} |
| 334 |
> |
throw new NoSuchFieldError("the Unsafe"); |
| 335 |
> |
}}); |
| 336 |
> |
} catch (java.security.PrivilegedActionException e) { |
| 337 |
> |
throw new RuntimeException("Could not initialize intrinsics", |
| 338 |
> |
e.getCause()); |
| 339 |
|
} |
| 340 |
|
} |
| 339 |
– |
|
| 341 |
|
} |
