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Fix and simplify freeing a direct buffer / Fix Android support

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Motivation:

6e8ba291cf introduced a regression in Android because Android does not have sun.nio.ch.DirectBuffer (see #2330.)  I also found PlatformDependent0.freeDirectBuffer() and freeDirectBufferUnsafe() are pretty much same after the commit and the unsafe version should be removed.

Modifications:

- Merge PlatformDependent0.freeDirectBuffer() and freeDirectBufferUnsafe() into one method.
- Make the Unsafe unavailable when sun.nio.ch.DirectBuffer is unavailable.  We could keep the Unsafe available and handle the sun.nio.ch.DirectBuffer case separately, but I don't want to complicate our code just because of that.  All supported JDK versions have sun.nio.ch.DirectBuffer if the Unsafe is available.

Result:

Simpler code. Fixes Android support (#2330)
This commit is contained in:
Trustin Lee 2014-03-20 11:11:07 +09:00
parent cf2c8b40ae
commit 2afe58f5f1
2 changed files with 17 additions and 31 deletions
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8
common/src/main/java/io/netty/util/internal/PlatformDependent.java
View File

@ -251,12 +251,8 @@ public final class PlatformDependent {
* the current platform does not support this operation or the specified buffer is not a direct buffer.
*/
public static void freeDirectBuffer(ByteBuffer buffer) {
if (buffer.isDirect()) {
if (hasUnsafe()) {
PlatformDependent0.freeDirectBufferUnsafe(buffer);
} else {
PlatformDependent0.freeDirectBuffer(buffer);
}
if (hasUnsafe()) {
PlatformDependent0.freeDirectBuffer(buffer);
}
}

40
common/src/main/java/io/netty/util/internal/PlatformDependent0.java
View File

@ -48,39 +48,40 @@ final class PlatformDependent0 {
private static final boolean UNALIGNED;
static {
ByteBuffer direct = ByteBuffer.allocateDirect(1);
Field cleanerField;
boolean directBufferFreeable = false;
try {
cleanerField = direct.getClass().getDeclaredField("cleaner");
cleanerField.setAccessible(true);
Cleaner cleaner = (Cleaner) cleanerField.get(direct);
cleaner.clean();
Class<?> cls = Class.forName("sun.nio.ch.DirectBuffer", false, PlatformDependent0.class.getClassLoader());
Method method = cls.getMethod("cleaner");
if ("sun.misc.Cleaner".equals(method.getReturnType().getName())) {
directBufferFreeable = true;
}
} catch (Throwable t) {
cleanerField = null;
// We don't have sun.nio.ch.DirectBuffer.cleaner().
}
logger.debug("java.nio.ByteBuffer.cleaner: {}", cleanerField != null? "available" : "unavailable");
logger.debug("sun.nio.ch.DirectBuffer.cleaner(): {}", directBufferFreeable? "available" : "unavailable");
Field addressField;
try {
addressField = Buffer.class.getDeclaredField("address");
addressField.setAccessible(true);
if (addressField.getLong(ByteBuffer.allocate(1)) != 0) {
// A heap buffer must have 0 address.
addressField = null;
} else {
direct = ByteBuffer.allocateDirect(1);
ByteBuffer direct = ByteBuffer.allocateDirect(1);
if (addressField.getLong(direct) == 0) {
// A direct buffer must have non-zero address.
addressField = null;
}
Cleaner cleaner = (Cleaner) cleanerField.get(direct);
cleaner.clean();
}
} catch (Throwable t) {
// Failed to access the address field.
addressField = null;
}
logger.debug("java.nio.Buffer.address: {}", addressField != null? "available" : "unavailable");
Unsafe unsafe;
if (addressField != null && cleanerField != null) {
if (addressField != null && directBufferFreeable) {
try {
Field unsafeField = Unsafe.class.getDeclaredField("theUnsafe");
unsafeField.setAccessible(true);
@ -104,6 +105,7 @@ final class PlatformDependent0 {
throw e;
}
} catch (Throwable cause) {
// Unsafe.copyMemory(Object, long, Object, long, long) unavailable.
unsafe = null;
}
} else {
@ -111,6 +113,7 @@ final class PlatformDependent0 {
// Let's just pretend unsafe is unavailable for overall simplicity.
unsafe = null;
}
UNSAFE = unsafe;
if (unsafe == null) {
@ -144,19 +147,6 @@ final class PlatformDependent0 {
UNSAFE.throwException(t);
}
static void freeDirectBufferUnsafe(ByteBuffer buffer) {
try {
Cleaner cleaner = ((DirectBuffer) buffer).cleaner();
if (cleaner == null) {
throw new IllegalArgumentException(
"attempted to deallocate the buffer which was allocated via JNIEnv->NewDirectByteBuffer()");
}
cleaner.clean();
} catch (Throwable t) {
// Nothing we can do here.
}
}
static void freeDirectBuffer(ByteBuffer buffer) {
if (!(buffer instanceof DirectBuffer)) {
return;