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Apache Geode provides a database-like consistency model, reliable transaction processing and a shared-nothing architecture to maintain very low latency performance with high concurrency processing
/*
* Licensed to the Apache Software Foundation (ASF) under one or more contributor license
* agreements. See the NOTICE file distributed with this work for additional information regarding
* copyright ownership. The ASF licenses this file to You under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the License. You may obtain a
* copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License
* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
* or implied. See the License for the specific language governing permissions and limitations under
* the License.
*/
package org.apache.geode.internal.offheap;
import org.apache.geode.annotations.Immutable;
import org.apache.geode.internal.cache.CachedDeserializableFactory;
import org.apache.geode.internal.cache.DiskId;
import org.apache.geode.internal.cache.EntryEventImpl;
import org.apache.geode.internal.cache.RegionEntryContext;
import org.apache.geode.internal.cache.Token;
import org.apache.geode.internal.cache.entries.DiskEntry;
import org.apache.geode.internal.cache.entries.OffHeapRegionEntry;
import org.apache.geode.internal.offheap.annotations.Released;
import org.apache.geode.internal.offheap.annotations.Retained;
import org.apache.geode.internal.offheap.annotations.Unretained;
import org.apache.geode.internal.serialization.DSCODE;
/**
* The class just has static methods that operate on instances of {@link OffHeapRegionEntry}. It
* allows common code to be shared for all the classes we have that implement
* {@link OffHeapRegionEntry}.
*
* @since Geode 1.0
*/
public class OffHeapRegionEntryHelper {
protected static final long NULL_ADDRESS = 0L << 1;
protected static final long INVALID_ADDRESS = 1L << 1;
protected static final long LOCAL_INVALID_ADDRESS = 2L << 1;
protected static final long DESTROYED_ADDRESS = 3L << 1;
protected static final long REMOVED_PHASE1_ADDRESS = 4L << 1;
protected static final long REMOVED_PHASE2_ADDRESS = 5L << 1;
protected static final long END_OF_STREAM_ADDRESS = 6L << 1;
protected static final long NOT_AVAILABLE_ADDRESS = 7L << 1;
protected static final long TOMBSTONE_ADDRESS = 8L << 1;
public static final int MAX_LENGTH_FOR_DATA_AS_ADDRESS = 8;
@Immutable
private static final Token[] addrToObj =
new Token[] {null, Token.INVALID, Token.LOCAL_INVALID, Token.DESTROYED, Token.REMOVED_PHASE1,
Token.REMOVED_PHASE2, Token.END_OF_STREAM, Token.NOT_AVAILABLE, Token.TOMBSTONE,};
private static long objectToAddress(@Unretained Object v) {
if (v instanceof StoredObject)
return ((StoredObject) v).getAddress();
if (v == null)
return NULL_ADDRESS;
if (v == Token.TOMBSTONE)
return TOMBSTONE_ADDRESS;
if (v == Token.INVALID)
return INVALID_ADDRESS;
if (v == Token.LOCAL_INVALID)
return LOCAL_INVALID_ADDRESS;
if (v == Token.DESTROYED)
return DESTROYED_ADDRESS;
if (v == Token.REMOVED_PHASE1)
return REMOVED_PHASE1_ADDRESS;
if (v == Token.REMOVED_PHASE2)
return REMOVED_PHASE2_ADDRESS;
if (v == Token.END_OF_STREAM)
return END_OF_STREAM_ADDRESS;
if (v == Token.NOT_AVAILABLE)
return NOT_AVAILABLE_ADDRESS;
throw new IllegalStateException("Can not convert " + v + " to an off heap address.");
}
/**
* This method may release the object stored at ohAddress if the result needs to be decompressed
* and the decompress parameter is true. This decompressed result will be on the heap.
*
* @param ohAddress OFF_HEAP_ADDRESS
* @param decompress true if off-heap value should be decompressed before returning
* @param context used for decompression
* @return OFF_HEAP_OBJECT (sometimes)
*/
@Unretained
@Retained
public static Object addressToObject(@Released @Retained long ohAddress, boolean decompress,
RegionEntryContext context) {
if (isOffHeap(ohAddress)) {
@Unretained
OffHeapStoredObject chunk = new OffHeapStoredObject(ohAddress);
@Unretained
Object result = chunk;
if (decompress && chunk.isCompressed()) {
try {
// to fix bug 47982 need to:
byte[] decompressedBytes = chunk.getDecompressedBytes(context);
if (chunk.isSerialized()) {
// return a VMCachedDeserializable with the decompressed serialized bytes since chunk is
// serialized
result = CachedDeserializableFactory.create(decompressedBytes, context.getCache());
} else {
// return a byte[] since chunk is not serialized
result = decompressedBytes;
}
} finally {
// decompress is only true when this method is called by _getValueRetain.
// In that case the caller has already retained ohAddress because it thought
// we would return it. But we have unwrapped it and are returning the decompressed
// results.
// So we need to release the chunk here.
chunk.release();
}
}
return result;
} else if ((ohAddress & ENCODED_BIT) != 0) {
TinyStoredObject daa = new TinyStoredObject(ohAddress);
Object result = daa;
if (decompress && daa.isCompressed()) {
byte[] decompressedBytes = daa.getDecompressedBytes(context);
if (daa.isSerialized()) {
// return a VMCachedDeserializable with the decompressed serialized bytes since daa is
// serialized
result = CachedDeserializableFactory.create(decompressedBytes, context.getCache());
} else {
// return a byte[] since daa is not serialized
result = decompressedBytes;
}
}
return result;
} else {
return addrToObj[(int) ohAddress >> 1];
}
}
public static int getSerializedLength(TinyStoredObject dataAsAddress) {
final long ohAddress = dataAsAddress.getAddress();
if ((ohAddress & ENCODED_BIT) != 0) {
boolean isLong = (ohAddress & LONG_BIT) != 0;
if (isLong) {
return 9;
} else {
return (int) ((ohAddress & SIZE_MASK) >> SIZE_SHIFT);
}
} else {
return 0;
}
}
/*
* This method is optimized for cases where if the caller wants to convert address to a Token
* compared to addressToObject which would deserialize the value.
*/
private static Token addressToToken(long ohAddress) {
if (isOffHeap(ohAddress) || (ohAddress & ENCODED_BIT) != 0) {
return Token.NOT_A_TOKEN;
} else {
return addrToObj[(int) ohAddress >> 1];
}
}
private static void releaseAddress(@Released long ohAddress) {
if (isOffHeap(ohAddress)) {
OffHeapStoredObject.release(ohAddress);
}
}
/**
* The address in 're' will be @Released.
*/
public static void releaseEntry(@Released OffHeapRegionEntry re) {
if (re instanceof DiskEntry) {
DiskId did = ((DiskEntry) re).getDiskId();
if (did != null && did.isPendingAsync()) {
synchronized (did) {
// This may not be needed so remove this call if it causes problems.
// We no longer need this entry to be written to disk so unschedule it
// before we change its value to REMOVED_PHASE2.
did.setPendingAsync(false);
setValue(re, Token.REMOVED_PHASE2);
return;
}
}
}
setValue(re, Token.REMOVED_PHASE2);
}
public static void releaseEntry(@Unretained OffHeapRegionEntry re,
@Released StoredObject expectedValue) {
long oldAddress = objectToAddress(expectedValue);
final long newAddress = objectToAddress(Token.REMOVED_PHASE2);
if (re.setAddress(oldAddress, newAddress)) {
releaseAddress(oldAddress);
} /*
* else { if (!calledSetValue || re.getAddress() != newAddress) { expectedValue.release(); } }
*/
}
/**
* This bit is set to indicate that this address has data encoded in it.
*/
private static final long ENCODED_BIT = 1L;
/**
* This bit is set to indicate that the encoded data is serialized.
*/
static final long SERIALIZED_BIT = 2L;
/**
* This bit is set to indicate that the encoded data is compressed.
*/
static final long COMPRESSED_BIT = 4L;
/**
* This bit is set to indicate that the encoded data is a long whose value fits in 7 bytes.
*/
private static final long LONG_BIT = 8L;
/**
* size is in the range 0..7 so we only need 3 bits.
*/
private static final long SIZE_MASK = 0x70L;
/**
* number of bits to shift the size by.
*/
private static final int SIZE_SHIFT = 4;
// the msb of this byte is currently unused
/**
* Returns 0 if the data could not be encoded as an address.
*/
public static long encodeDataAsAddress(byte[] v, boolean isSerialized, boolean isCompressed) {
if (v.length < MAX_LENGTH_FOR_DATA_AS_ADDRESS) {
long result = 0L;
for (int i = 0; i < v.length; i++) {
result |= v[i] & 0x00ff;
result <<= 8;
}
result |= (v.length << SIZE_SHIFT) | ENCODED_BIT;
if (isSerialized) {
result |= SERIALIZED_BIT;
}
if (isCompressed) {
result |= COMPRESSED_BIT;
}
return result;
} else if (isSerialized && !isCompressed) {
// Check for some special types that take more than 7 bytes to serialize
// but that might be able to be inlined with less than 8 bytes.
if (v[0] == DSCODE.LONG.toByte()) {
// A long is currently always serialized as 8 bytes (9 if you include the dscode).
// But many long values will actually be small enough for is to encode in 7 bytes.
if ((v[1] == 0 && (v[2] & 0x80) == 0) || (v[1] == -1 && (v[2] & 0x80) != 0)) {
// The long can be encoded as 7 bytes since the most signification byte
// is simply an extension of the sign byte on the second most signification byte.
long result = 0L;
for (int i = 2; i < v.length; i++) {
result |= v[i] & 0x00ff;
result <<= 8;
}
result |= (7 << SIZE_SHIFT) | LONG_BIT | SERIALIZED_BIT | ENCODED_BIT;
return result;
}
}
}
return 0L;
}
static Object decodeAddressToObject(long ohAddress) {
byte[] bytes = decodeUncompressedAddressToBytes(ohAddress);
boolean isSerialized = (ohAddress & SERIALIZED_BIT) != 0;
if (isSerialized) {
return EntryEventImpl.deserialize(bytes);
} else {
return bytes;
}
}
static int decodeAddressToDataSize(long addr) {
if ((addr & ENCODED_BIT) == 0) {
throw new AssertionError("Invalid address: " + addr);
}
boolean isLong = (addr & LONG_BIT) != 0;
if (isLong) {
return 9;
}
return (int) ((addr & SIZE_MASK) >> SIZE_SHIFT);
}
/**
* Returns the bytes encoded in the given address. Note that compressed addresses are not
* supported by this method.
*
* @throws UnsupportedOperationException if the address has compressed data
*/
static byte[] decodeUncompressedAddressToBytes(long addr) {
if ((addr & COMPRESSED_BIT) != 0) {
throw new AssertionError("Did not expect encoded address to be compressed");
}
return decodeAddressToRawBytes(addr);
}
/**
* Returns the "raw" bytes that have been encoded in the given address. Note that if address is
* compressed then the raw bytes are the compressed bytes.
*/
static byte[] decodeAddressToRawBytes(long addr) {
if ((addr & ENCODED_BIT) == 0) {
throw new AssertionError("Invalid address: " + addr);
}
int size = (int) ((addr & SIZE_MASK) >> SIZE_SHIFT);
boolean isLong = (addr & LONG_BIT) != 0;
byte[] bytes;
if (isLong) {
bytes = new byte[9];
bytes[0] = DSCODE.LONG.toByte();
for (int i = 8; i >= 2; i--) {
addr >>= 8;
bytes[i] = (byte) (addr & 0x00ff);
}
if ((bytes[2] & 0x80) != 0) {
bytes[1] = -1;
} else {
bytes[1] = 0;
}
} else {
bytes = new byte[size];
for (int i = size - 1; i >= 0; i--) {
addr >>= 8;
bytes[i] = (byte) (addr & 0x00ff);
}
}
return bytes;
}
/**
* The previous value at the address in 're' will be @Released and then the address in 're' will
* be set to the @Unretained address of 'v'.
*/
public static void setValue(@Released OffHeapRegionEntry re, @Unretained Object v) {
// setValue is called when synced so I don't need to worry
// about oldAddress being released by someone else.
final long newAddress = objectToAddress(v);
long oldAddress;
do {
oldAddress = re.getAddress();
} while (!re.setAddress(oldAddress, newAddress));
ReferenceCountHelper.setReferenceCountOwner(re);
releaseAddress(oldAddress);
ReferenceCountHelper.setReferenceCountOwner(null);
}
public static Token getValueAsToken(@Unretained OffHeapRegionEntry re) {
return addressToToken(re.getAddress());
}
@Unretained
public static Object _getValue(@Unretained OffHeapRegionEntry re) {
return addressToObject(re.getAddress(), false, null); // no context needed so decompress is
// false
}
public static boolean isOffHeap(long addr) {
if ((addr & ENCODED_BIT) != 0)
return false;
if (addr < 0)
return true;
addr >>= 1; // shift right 1 to convert to array index;
return addr >= addrToObj.length;
}
/**
* If the value stored at the location held in 're' is returned, then it will be Retained. If the
* value returned is 're' decompressed into another off-heap location, then 're' will be
* Unretained but the new, decompressed value will be Retained. Therefore, whichever is returned
* (the value at the address in 're' or the decompressed value) it will have been Retained.
*
* @return possible OFF_HEAP_OBJECT (caller must release)
*/
@Retained
public static Object _getValueRetain(@Retained @Unretained OffHeapRegionEntry re,
boolean decompress, RegionEntryContext context) {
int retryCount = 0;
@Retained
long addr = re.getAddress();
while (isOffHeap(addr)) {
if (OffHeapStoredObject.retain(addr)) {
@Unretained
long addr2 = re.getAddress();
if (addr != addr2) {
retryCount = 0;
OffHeapStoredObject.release(addr);
// spin around and try again.
addr = addr2;
} else {
return addressToObject(addr, decompress, context);
}
} else {
// spin around and try again
long addr2 = re.getAddress();
retryCount++;
if (retryCount > 100) {
throw new IllegalStateException("retain failed addr=" + addr + " addr2=" + addr
+ " 100 times" + " history=" + ReferenceCountHelper.getFreeRefCountInfo(addr));
}
addr = addr2;
// Since retain returned false our region entry should have a different
// value in it. However the actual address could be the exact same one
// because addr was released, then reallocated from the free list and set
// back into this region entry. See bug 47782
}
}
return addressToObject(addr, decompress, context);
}
public static boolean isSerialized(long address) {
return (address & SERIALIZED_BIT) != 0;
}
public static boolean isCompressed(long address) {
return (address & COMPRESSED_BIT) != 0;
}
private static final ThreadLocal