/*******************************************************************************
* Copyright (c) 2005, 2016 QNX Software Systems and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* QNX - Initial API and implementation
* Symbian - Add some non-javadoc implementation notes
* Markus Schorn (Wind River Systems)
* IBM Corporation
* Sergey Prigogin (Google)
* Stefan Xenos (Google)
*******************************************************************************/
package org.eclipse.jdt.internal.core.nd.db;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.channels.ClosedByInterruptException;
import java.nio.channels.ClosedChannelException;
import java.nio.channels.FileChannel;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.Set;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.OperationCanceledException;
import org.eclipse.core.runtime.Status;
import org.eclipse.jdt.internal.core.nd.IndexExceptionBuilder;
import org.eclipse.jdt.internal.core.nd.db.ModificationLog.Tag;
import org.eclipse.osgi.util.NLS;
/**
* Database encapsulates access to a flat binary format file with a memory-manager-like API for
* obtaining and releasing areas of storage (memory).
* <p>
* Some terminology is used throughout this class: A block is a variable-size piece of
* contiguous memory returned by malloc. A chunk is a fixed-size piece of contiguous memory
* that is the atomic unit for paging, caching, reads, and writes. A free block is contiguous
* variable-length piece of memory that is created by free and is potentially usable by malloc.
* Most chunks contain multiple blocks and free blocks, but it is possible for a single block
* to use multiple chunks. Such blocks are referred to as "large blocks". A free block is always
* smaller than a chunk.
*/
/*
* The file encapsulated is divided into Chunks of size CHUNK_SIZE, and a table of contents
* mapping chunk index to chunk address is maintained. Chunk structure exists only conceptually -
* it is not a structure that appears in the file.
*
* ===== The first chunk is used by Database itself for house-keeping purposes and has structure
*
* offset content
* _____________________________
* 0 | version number
* INT_SIZE | pointer to head of linked list of blocks of size MIN_BLOCK_DELTAS*BLOCK_SIZE_DELTA
* .. | ...
* INT_SIZE * (M + 1) | pointer to head of linked list of blocks of size (M + MIN_BLOCK_DELTAS) * BLOCK_SIZE_DELTA
* FREE_BLOCK_OFFSET | chunk number for the root of the large block free space trie
* WRITE_NUMBER_OFFSET | long integer which is incremented on every write
* MALLOC_STATS_OFFSET | memory usage statistics
* DATA_AREA | The database singletons are stored here and use the remainder of chunk 0
*
* M = CHUNK_SIZE / BLOCK_SIZE_DELTA - MIN_BLOCK_DELTAS
*
* ===== block structure (for free/unused blocks)
*
* offset content
* _____________________________
* 0 | size of block (positive indicates an unused block) (2 bytes)
* PREV_OFFSET | pointer to previous block (of same size) (only in free blocks)
* NEXT_OFFSET | pointer to next block (of same size) (only in free blocks)
* ... | unused space
*
*====== block structure (for allocated blocks)
*
* offset content
* _____________________________
* 0 | size of block (negative indicates the block is in use) (2 bytes)
* 2 | content of the struct
*
*/
public class Database {
public static final int CHAR_SIZE = 2;
public static final int BYTE_SIZE = 1;
public static final int SHORT_SIZE = 2;
public static final int INT_SIZE = 4;
public static final int LONG_SIZE = 8;
public static final int CHUNK_SIZE = 1024 * 4;
public static final int OFFSET_IN_CHUNK_MASK= CHUNK_SIZE - 1;
public static final int BLOCK_HEADER_SIZE = SHORT_SIZE;
public static final int BLOCK_SIZE_DELTA_BITS = 3;
public static final int BLOCK_SIZE_DELTA= 1 << BLOCK_SIZE_DELTA_BITS;
// Fields that are only used by free blocks
private static final int BLOCK_PREV_OFFSET = BLOCK_HEADER_SIZE;
private static final int BLOCK_NEXT_OFFSET = BLOCK_HEADER_SIZE + INT_SIZE;
private static final int FREE_BLOCK_HEADER_SIZE = BLOCK_NEXT_OFFSET + INT_SIZE;
// Must be enough multiples of BLOCK_SIZE_DELTA in order to fit the free block header
public static final int MIN_BLOCK_DELTAS = (FREE_BLOCK_HEADER_SIZE + BLOCK_SIZE_DELTA - 1) / BLOCK_SIZE_DELTA;
public static final int MAX_BLOCK_DELTAS = (CHUNK_SIZE - LargeBlock.HEADER_SIZE - LargeBlock.FOOTER_SIZE)
/ BLOCK_SIZE_DELTA;
public static final int MAX_SINGLE_BLOCK_MALLOC_SIZE = MAX_BLOCK_DELTAS * BLOCK_SIZE_DELTA - BLOCK_HEADER_SIZE;
public static final int PTR_SIZE = 4; // size of a pointer in the database in bytes
public static final int STRING_SIZE = PTR_SIZE;
public static final int FLOAT_SIZE = INT_SIZE;
public static final int DOUBLE_SIZE = LONG_SIZE;
public static final long MAX_DB_SIZE= ((long) 1 << (Integer.SIZE + BLOCK_SIZE_DELTA_BITS));
public static final long MAX_MALLOC_SIZE = MAX_DB_SIZE - LargeBlock.HEADER_SIZE - LargeBlock.FOOTER_SIZE
- CHUNK_SIZE - BLOCK_HEADER_SIZE;
public static final int VERSION_OFFSET = 0;
public static final int MALLOC_TABLE_OFFSET = VERSION_OFFSET + INT_SIZE;
public static final int FREE_BLOCK_OFFSET = MALLOC_TABLE_OFFSET
+ (CHUNK_SIZE / BLOCK_SIZE_DELTA - MIN_BLOCK_DELTAS + 1) * INT_SIZE;
public static final int WRITE_NUMBER_OFFSET = FREE_BLOCK_OFFSET + PTR_SIZE;
public static final int MALLOC_STATS_OFFSET = WRITE_NUMBER_OFFSET + LONG_SIZE;
public static final int DATA_AREA_OFFSET = MALLOC_STATS_OFFSET + MemoryStats.SIZE;
public static final int NUM_HEADER_CHUNKS = 1;
// Malloc pool IDs (used for classifying memory allocations and recording statistics about them)
/** Misc pool -- may be used for any purpose that doesn't fit the IDs below. */
public static final short POOL_MISC = 0x0000;
public static final short POOL_BTREE = 0x0001;
public static final short POOL_DB_PROPERTIES = 0x0002;
public static final short POOL_STRING_LONG = 0x0003;
public static final short POOL_STRING_SHORT = 0x0004;
public static final short POOL_LINKED_LIST = 0x0005;
public static final short POOL_STRING_SET = 0x0006;
public static final short POOL_GROWABLE_ARRAY = 0x0007;
/** Id for the first node type. All node types will record their stats in a pool whose ID is POOL_FIRST_NODE_TYPE + node_id*/
public static final short POOL_FIRST_NODE_TYPE = 0x0100;
public static class ChunkStats {
public final int totalChunks;
public final int chunksInMemory;
public final int dirtyChunks;
public final int nonDirtyChunksNotInCache;
public ChunkStats(int totalChunks, int chunksInMemory, int dirtyChunks, int nonDirtyChunksNotInCache) {
this.totalChunks = totalChunks;
this.chunksInMemory = chunksInMemory;
this.dirtyChunks = dirtyChunks;
this.nonDirtyChunksNotInCache = nonDirtyChunksNotInCache;
}
public String toString() {
return "Chunks: total = " + this.totalChunks + ", in memory = " + this.chunksInMemory //$NON-NLS-1$//$NON-NLS-2$
+ ", dirty = " + this.dirtyChunks + ", not in cache = " + this.nonDirtyChunksNotInCache; //$NON-NLS-1$//$NON-NLS-2$
}
}
/**
* For loops that scan through the chunks list, this imposes a maximum number of iterations before the loop must
* release the chunk cache mutex.
*/
private static final int MAX_ITERATIONS_PER_LOCK = 256;
private static final int WRITE_BUFFER_SIZE = CHUNK_SIZE * 32;
/**
* True iff large chunk self-diagnostics should be enabled.
*/
public static boolean DEBUG_FREE_SPACE;
public static boolean DEBUG_PAGE_CACHE;
private final File fLocation;
private final boolean fReadOnly;
private RandomAccessFile fFile;
private boolean fExclusiveLock; // Necessary for any write operation.
private boolean fLocked; // Necessary for any operation.
private boolean fIsMarkedIncomplete;
private int fVersion;
private final Chunk fHeaderChunk;
/**
* Stores the {@link Chunk} associated with each page number or null if the chunk isn't loaded. Synchronize on
* {@link #fCache} before accessing.
*/
Chunk[] fChunks;
private int fChunksUsed;
private ChunkCache fCache;
private long malloced;
private long freed;
private long cacheHits;
private long cacheMisses;
private long bytesWritten;
private long totalReadTimeMs;
private MemoryStats memoryUsage;
public Chunk fMostRecentlyFetchedChunk;
/**
* Contains the set of Chunks in this Database for which the Chunk.dirty flag is set to true.
* Protected by the database write lock. This set does not contain the header chunk, which is
* always handled as a special case by the code that flushes chunks.
*/
private HashSet<Chunk> dirtyChunkSet = new HashSet<>();
private long totalFlushTime;
private long totalWriteTimeMs;
private long pageWritesBytes;
private long nextValidation;
private long validateCounter;
public static final double MIN_BYTES_PER_MILLISECOND = 20480.0;
private final ModificationLog log = new ModificationLog(0);
private final Tag mallocTag;
private final Tag freeTag;
/**
* Construct a new Database object, creating a backing file if necessary.
* @param location the local file path for the database
* @param cache the cache to be used optimization
* @param version the version number to store in the database (only applicable for new databases)
* @param openReadOnly whether this Database object will ever need writing to
* @throws IndexException
*/
public Database(File location, ChunkCache cache, int version, boolean openReadOnly) throws IndexException {
this.mallocTag = ModificationLog.createTag("Calling Database.malloc"); //$NON-NLS-1$
this.freeTag = ModificationLog.createTag("Calling Database.free"); //$NON-NLS-1$
try {
this.fLocation = location;
this.fReadOnly= openReadOnly;
this.fCache= cache;
openFile();
int nChunksOnDisk = (int) (this.fFile.length() / CHUNK_SIZE);
this.fHeaderChunk= new Chunk(this, 0);
if (nChunksOnDisk <= 0) {
this.fVersion= version;
this.fChunks= new Chunk[1];
this.fChunksUsed = this.fChunks.length;
} else {
this.fHeaderChunk.read();
this.fVersion= this.fHeaderChunk.getInt(VERSION_OFFSET);
this.fChunks = new Chunk[nChunksOnDisk]; // chunk[0] is unused.
this.fChunksUsed = nChunksOnDisk;
}
} catch (IOException e) {
throw new IndexException(new DBStatus(e));
}
this.memoryUsage = new MemoryStats(this.fHeaderChunk, MALLOC_STATS_OFFSET);
}
private static int divideRoundingUp(long num, long den) {
return (int) ((num + den - 1) / den);
}
private void openFile() throws FileNotFoundException {
this.fFile = new RandomAccessFile(this.fLocation, this.fReadOnly ? "r" : "rw"); //$NON-NLS-1$ //$NON-NLS-2$
}
void read(ByteBuffer buf, long position) throws IOException {
int retries= 0;
do {
try {
this.fFile.getChannel().read(buf, position);
return;
} catch (ClosedChannelException e) {
// Always reopen the file if possible or subsequent reads will fail.
openFile();
// This is the most common type of interruption. If another thread called Thread.interrupt,
// throw an OperationCanceledException.
if (e instanceof ClosedByInterruptException) {
throw new OperationCanceledException();
}
// If we've retried too many times, just rethrow the exception.
if (++retries >= 20) {
throw e;
}
// Otherwise, retry
}
} while (true);
}
public ModificationLog getLog() {
return this.log;
}
/**
* Attempts to write to the given position in the file. Will retry if interrupted by Thread.interrupt() until,
* the write succeeds. It will return true if any call to Thread.interrupt() was detected.
*
* @return true iff a call to Thread.interrupt() was detected at any point during the operation.
* @throws IOException
*/
boolean write(ByteBuffer buf, long position) throws IOException {
this.bytesWritten += buf.limit();
return performUninterruptableWrite(() -> {this.fFile.getChannel().write(buf, position);});
}
private static interface IORunnable {
void run() throws IOException;
}
/**
* Attempts to perform an uninterruptable write operation on the database. Returns true if an attempt was made
* to interrupt it.
*
* @throws IOException
*/
private boolean performUninterruptableWrite(IORunnable runnable) throws IOException {
boolean interrupted = false;
int retries= 0;
while (true) {
try {
runnable.run();
return interrupted;
} catch (ClosedChannelException e) {
openFile();
if (e instanceof ClosedByInterruptException) {
// Retry forever if necessary as long as another thread is calling Thread.interrupt
interrupted = true;
} else {
if (++retries > 20) {
throw e;
}
}
}
}
}
public void transferTo(FileChannel target) throws IOException {
assert this.fLocked;
final FileChannel from= this.fFile.getChannel();
long nRead = 0;
long position = 0;
long size = from.size();
while (position < size) {
nRead = from.transferTo(position, 4096 * 16, target);
if (nRead == 0) {
break; // Should not happen.
} else {
position+= nRead;
}
}
}
public int getVersion() {
return this.fVersion;
}
public void setVersion(int version) throws IndexException {
assert this.fExclusiveLock;
this.fHeaderChunk.putInt(VERSION_OFFSET, version);
this.fVersion= version;
}
/**
* Empty the contents of the Database, make it ready to start again. Interrupting the thread with
* {@link Thread#interrupt()} won't interrupt the write. Returns true iff the thread was interrupted
* with {@link Thread#interrupt()}.
*
* @throws IndexException
*/
public boolean clear(int version) throws IndexException {
assert this.fExclusiveLock;
boolean wasCanceled = false;
removeChunksFromCache();
this.log.clear();
this.fVersion= version;
// Clear the first chunk.
this.fHeaderChunk.clear(0, CHUNK_SIZE);
// Chunks have been removed from the cache, so we may just reset the array of chunks.
this.fChunks = new Chunk[] {null};
this.dirtyChunkSet.clear();
this.fChunksUsed = this.fChunks.length;
try {
wasCanceled = this.fHeaderChunk.flush() || wasCanceled; // Zero out header chunk.
wasCanceled = performUninterruptableWrite(() -> {
this.fFile.getChannel().truncate(CHUNK_SIZE);
}) || wasCanceled;
this.bytesWritten += CHUNK_SIZE;
} catch (IOException e) {
Package.log(e);
}
this.malloced = this.freed = 0;
/*
* This is for debugging purposes in order to simulate having a very large Nd database.
* This will set aside the specified number of chunks.
* Nothing uses these chunks so subsequent allocations come after these fillers.
* The special function createNewChunks allocates all of these chunks at once.
* 524288 for a file starting at 2G
* 8388608 for a file starting at 32G
*
*/
long setasideChunks = Long.getLong("org.eclipse.jdt.core.parser.nd.chunks", 0); //$NON-NLS-1$
if (setasideChunks != 0) {
setVersion(getVersion());
createNewChunks((int) setasideChunks);
wasCanceled = flush() || wasCanceled;
}
this.memoryUsage.refresh();
return wasCanceled;
}
private void removeChunksFromCache() {
int scanIndex = NUM_HEADER_CHUNKS;
while (scanIndex < this.fChunksUsed) {
synchronized (this.fCache) {
int countMax = Math.min(MAX_ITERATIONS_PER_LOCK, this.fChunksUsed - scanIndex);
for (int count = 0; count < countMax; count++) {
Chunk chunk = this.fChunks[scanIndex++];
if (chunk != null) {
this.fCache.remove(chunk);
if (DEBUG_PAGE_CACHE) {
System.out.println("CHUNK " + chunk.fSequenceNumber //$NON-NLS-1$
+ ": removing from vector in removeChunksFromCache - instance " //$NON-NLS-1$
+ System.identityHashCode(chunk));
}
this.fChunks[chunk.fSequenceNumber] = null;
}
}
}
}
}
/**
* Return the Chunk that contains the given offset.
*
* @throws IndexException
*/
public Chunk getChunk(long offset) throws IndexException {
assertLocked();
if (offset < CHUNK_SIZE) {
this.fMostRecentlyFetchedChunk = this.fHeaderChunk;
return this.fHeaderChunk;
}
long long_index = offset / CHUNK_SIZE;
assert long_index < Integer.MAX_VALUE;
final int index = (int) long_index;
Chunk chunk;
synchronized (this.fCache) {
assert this.fLocked;
if (index < 0 || index >= this.fChunks.length) {
databaseCorruptionDetected();
}
chunk = this.fChunks[index];
}
long readStartMs = 0;
long readEndMs = 0;
// Read the new chunk outside of any synchronized block (this allows parallel reads and prevents background
// threads from retaining a lock that blocks the UI while the background thread performs I/O).
boolean cacheMiss = (chunk == null);
if (cacheMiss) {
readStartMs = System.currentTimeMillis();
chunk = new Chunk(this, index);
chunk.read();
readEndMs = System.currentTimeMillis();
}
synchronized (this.fCache) {
if (cacheMiss) {
this.cacheMisses++;
this.totalReadTimeMs += (readEndMs - readStartMs);
} else {
this.cacheHits++;
}
Chunk newChunk = this.fChunks[index];
if (newChunk != chunk && newChunk != null) {
// Another thread fetched this chunk in the meantime. In this case, we should use the chunk fetched
// by the other thread.
if (DEBUG_PAGE_CACHE) {
System.out.println("CHUNK " + chunk.fSequenceNumber //$NON-NLS-1$
+ ": already fetched by another thread - instance " //$NON-NLS-1$
+ System.identityHashCode(chunk));
}
chunk = newChunk;
} else if (cacheMiss) {
if (DEBUG_PAGE_CACHE) {
System.out.println("CHUNK " + chunk.fSequenceNumber + ": inserted into vector - instance " //$NON-NLS-1$//$NON-NLS-2$
+ System.identityHashCode(chunk));
}
this.fChunks[index] = chunk;
}
this.fCache.add(chunk);
this.fMostRecentlyFetchedChunk = chunk;
}
return chunk;
}
public void assertLocked() {
if (!this.fLocked) {
throw new IllegalStateException("Database not locked!"); //$NON-NLS-1$
}
}
private void databaseCorruptionDetected() throws IndexException {
String msg = "Corrupted database: " + this.fLocation.getName(); //$NON-NLS-1$
throw new IndexException(new DBStatus(msg));
}
/**
* Copies numBytes from source to destination
*/
public void memcpy(long dest, long source, int numBytes) {
assert numBytes >= 0;
long endAddress = source + numBytes;
assert endAddress <= this.fChunksUsed * CHUNK_SIZE;
// TODO: make use of lower-level System.arrayCopy
for (int count = 0; count < numBytes; count++) {
putByte(dest + count, getByte(source + count));
}
}
/**
* Allocate a block out of the database.
*/
public long malloc(final long datasize, final short poolId) throws IndexException {
assert this.fExclusiveLock;
assert datasize >= 0;
assert datasize <= MAX_MALLOC_SIZE;
long result;
int usedSize;
this.log.start(this.mallocTag);
try {
if (datasize >= MAX_SINGLE_BLOCK_MALLOC_SIZE) {
int newChunkNum = createLargeBlock(datasize);
usedSize = Math.abs(getBlockHeaderForChunkNum(newChunkNum)) * CHUNK_SIZE;
result = (long) newChunkNum * CHUNK_SIZE + LargeBlock.HEADER_SIZE;
// Note that we identify large blocks by setting their block size to 0.
clearRange(result, usedSize - LargeBlock.HEADER_SIZE - LargeBlock.FOOTER_SIZE);
result = result + BLOCK_HEADER_SIZE;
} else {
long freeBlock = 0;
int needDeltas = divideRoundingUp(datasize + BLOCK_HEADER_SIZE, BLOCK_SIZE_DELTA);
if (needDeltas < MIN_BLOCK_DELTAS) {
needDeltas = MIN_BLOCK_DELTAS;
}
// Which block size.
int useDeltas;
for (useDeltas = needDeltas; useDeltas <= MAX_BLOCK_DELTAS; useDeltas++) {
freeBlock = getFirstBlock(useDeltas * BLOCK_SIZE_DELTA);
if (freeBlock != 0)
break;
}
// Get the block.
Chunk chunk;
if (freeBlock == 0) {
// Allocate a new chunk.
freeBlock = (long) (createLargeBlock(datasize)) * (long) CHUNK_SIZE + LargeBlock.HEADER_SIZE;
useDeltas = MAX_BLOCK_DELTAS;
chunk = getChunk(freeBlock);
} else {
chunk = getChunk(freeBlock);
chunk.makeDirty();
int blockReportedSize = chunk.getShort(freeBlock);
if (blockReportedSize != useDeltas * BLOCK_SIZE_DELTA) {
throw describeProblem()
.addProblemAddress("block size", freeBlock, SHORT_SIZE) //$NON-NLS-1$
.build(
"Heap corruption detected in free space list. Block " + freeBlock //$NON-NLS-1$
+ " reports a size of " + blockReportedSize + " but was in the list for blocks of size " //$NON-NLS-1$//$NON-NLS-2$
+ useDeltas * BLOCK_SIZE_DELTA);
}
removeBlock(chunk, useDeltas * BLOCK_SIZE_DELTA, freeBlock);
}
final int unusedDeltas = useDeltas - needDeltas;
if (unusedDeltas >= MIN_BLOCK_DELTAS) {
// Add in the unused part of our block.
addBlock(chunk, unusedDeltas * BLOCK_SIZE_DELTA, freeBlock + needDeltas * BLOCK_SIZE_DELTA);
useDeltas = needDeltas;
}
// Make our size negative to show in use.
usedSize = useDeltas * BLOCK_SIZE_DELTA;
chunk.putShort(freeBlock, (short) -usedSize);
// Clear out the block, lots of people are expecting this.
chunk.clear(freeBlock + BLOCK_HEADER_SIZE, usedSize - BLOCK_HEADER_SIZE);
result = freeBlock + BLOCK_HEADER_SIZE;
}
} finally {
this.log.end(this.mallocTag);
}
this.log.recordMalloc(result, usedSize - BLOCK_HEADER_SIZE);
this.malloced += usedSize;
this.memoryUsage.recordMalloc(poolId, usedSize);
if (DEBUG_FREE_SPACE) {
boolean performedValidation = periodicValidateFreeSpace();
if (performedValidation) {
verifyNotInFreeSpaceList(result);
}
}
return result;
}
/**
* Clears all the bytes in the given range by setting them to zero.
*
* @param startAddress first address to clear
* @param bytesToClear number of addresses to clear
*/
public void clearRange(long startAddress, long bytesToClear) {
if (bytesToClear == 0) {
return;
}
long endAddress = startAddress + bytesToClear;
assert endAddress <= (long) this.fChunksUsed * CHUNK_SIZE;
int blockNumber = (int) (startAddress / CHUNK_SIZE);
int firstBlockBytesToClear = (int) Math.min((((long) (blockNumber + 1) * CHUNK_SIZE) - startAddress), bytesToClear);
Chunk firstBlock = getChunk(startAddress);
firstBlock.clear(startAddress, firstBlockBytesToClear);
startAddress += firstBlockBytesToClear;
bytesToClear -= firstBlockBytesToClear;
while (bytesToClear > CHUNK_SIZE) {
Chunk nextBlock = getChunk(startAddress);
nextBlock.clear(startAddress, CHUNK_SIZE);
startAddress += CHUNK_SIZE;
bytesToClear -= CHUNK_SIZE;
}
if (bytesToClear > 0) {
Chunk nextBlock = getChunk(startAddress);
nextBlock.clear(startAddress, (int) bytesToClear);
}
}
/**
* Obtains a new block that can fit the given number of bytes (at minimum). Returns the
* chunk number.
*
* @param datasize minimum number of bytes needed
* @return the chunk number
*/
private int createLargeBlock(long datasize) {
final int neededChunks = getChunksNeededForBytes(datasize);
int freeBlockChunkNum = getFreeBlockFromTrie(neededChunks);
final int numChunks;
if (freeBlockChunkNum == 0) {
final int lastChunkNum = this.fChunksUsed;
numChunks = neededChunks;
// Check if the last block in the database is free. If so, unlink and expand it.
int lastBlockSize = getBlockFooterForChunkBefore(lastChunkNum);
if (lastBlockSize > 0) {
int startChunkNum = getFirstChunkOfBlockBefore(lastChunkNum);
unlinkFreeBlock(startChunkNum);
// Allocate additional new chunks such that the new chunk is large enough to
// handle this allocation.
createNewChunks(neededChunks - lastBlockSize);
freeBlockChunkNum = startChunkNum;
} else {
freeBlockChunkNum = createNewChunks(numChunks);
}
} else {
numChunks = getBlockHeaderForChunkNum(freeBlockChunkNum);
if (numChunks < neededChunks) {
throw describeProblem()
.addProblemAddress("chunk header", freeBlockChunkNum * CHUNK_SIZE, INT_SIZE) //$NON-NLS-1$
.build("A block in the free space trie was too small or wasn't actually free. Reported size = " //$NON-NLS-1$
+ numChunks + " chunks, requested size = " + neededChunks + " chunks"); //$NON-NLS-1$//$NON-NLS-2$
}
int footer = getBlockFooterForChunkBefore(freeBlockChunkNum + numChunks);
if (footer != numChunks) {
throw describeProblem()
.addProblemAddress("chunk header", freeBlockChunkNum * CHUNK_SIZE, INT_SIZE) //$NON-NLS-1$
.addProblemAddress("chunk footer", (freeBlockChunkNum + numChunks) * CHUNK_SIZE - INT_SIZE, INT_SIZE) //$NON-NLS-1$
.build("The header and footer didn't match for a block in the free space trie. Expected " //$NON-NLS-1$
+ numChunks + " but found " + footer); //$NON-NLS-1$
}
unlinkFreeBlock(freeBlockChunkNum);
}
final int resultChunkNum;
if (numChunks > neededChunks) {
// If the chunk we've selected is larger than necessary, split it. We have the
// choice of using either half of the block. In the interest of leaving more
// opportunities of merging large blocks, we leave the unused half of the block
// next to the larger adjacent block.
final int nextBlockChunkNum = freeBlockChunkNum + numChunks;
final int nextBlockSize = Math.abs(getBlockHeaderForChunkNum(nextBlockChunkNum));
final int prevBlockSize = Math.abs(getBlockFooterForChunkBefore(freeBlockChunkNum));
final int unusedChunks = numChunks - neededChunks;
if (nextBlockSize >= prevBlockSize) {
// Use the start of the block
resultChunkNum = freeBlockChunkNum;
// Return the last half of the block to the free block pool
linkFreeBlockToTrie(freeBlockChunkNum + neededChunks, unusedChunks);
} else {
// Use the end of the block
resultChunkNum = freeBlockChunkNum + unusedChunks;
// Return the first half of the block to the free block pool
linkFreeBlockToTrie(freeBlockChunkNum, unusedChunks);
}
} else {
resultChunkNum = freeBlockChunkNum;
}
// Fill in the header and footer
setBlockHeader(resultChunkNum, -neededChunks);
return resultChunkNum;
}
/**
* Unlinks a free block (which currently belongs to the free block trie) so that it may
* be reused.
*
* @param freeBlockChunkNum chunk number of the block to be unlinked
*/
private void unlinkFreeBlock(int freeBlockChunkNum) {
long freeBlockAddress = freeBlockChunkNum * CHUNK_SIZE;
int anotherBlockOfSameSize = 0;
int nextBlockChunkNum = getInt(freeBlockAddress + LargeBlock.NEXT_BLOCK_OFFSET);
int prevBlockChunkNum = getInt(freeBlockAddress + LargeBlock.PREV_BLOCK_OFFSET);
// Relink the linked list
if (nextBlockChunkNum != 0) {
anotherBlockOfSameSize = nextBlockChunkNum;
putInt(nextBlockChunkNum * CHUNK_SIZE + LargeBlock.PREV_BLOCK_OFFSET, prevBlockChunkNum);
}
if (prevBlockChunkNum != 0) {
anotherBlockOfSameSize = prevBlockChunkNum;
putInt(prevBlockChunkNum * CHUNK_SIZE + LargeBlock.NEXT_BLOCK_OFFSET, nextBlockChunkNum);
}
/**
* True iff this block was a block in the trie. False if it was attached to to the list of siblings but some
* other node in the list is the one in the trie.
*/
boolean wasInTrie = false;
long root = getInt(FREE_BLOCK_OFFSET);
if (root == freeBlockChunkNum) {
putInt(FREE_BLOCK_OFFSET, 0);
wasInTrie = true;
}
int freeBlockSize = getBlockHeaderForChunkNum(freeBlockChunkNum);
int parentChunkNum = getInt(freeBlockAddress + LargeBlock.PARENT_OFFSET);
if (parentChunkNum != 0) {
int currentSize = getBlockHeaderForChunkNum(parentChunkNum);
int difference = currentSize ^ freeBlockSize;
if (difference != 0) {
int firstDifference = LargeBlock.SIZE_OF_SIZE_FIELD * 8 - Integer.numberOfLeadingZeros(difference) - 1;
long locationOfChildPointer = parentChunkNum * CHUNK_SIZE + LargeBlock.CHILD_TABLE_OFFSET
+ (firstDifference * INT_SIZE);
int childChunkNum = getInt(locationOfChildPointer);
if (childChunkNum == freeBlockChunkNum) {
wasInTrie = true;
putInt(locationOfChildPointer, 0);
}
}
}
// If the removed block was the head of the linked list, we need to reinsert the following entry as the
// new head.
if (wasInTrie && anotherBlockOfSameSize != 0) {
insertChild(parentChunkNum, anotherBlockOfSameSize);
}
int currentParent = parentChunkNum;
for (int childIdx = 0; childIdx < LargeBlock.ENTRIES_IN_CHILD_TABLE; childIdx++) {
long childAddress = freeBlockAddress + LargeBlock.CHILD_TABLE_OFFSET + (childIdx * INT_SIZE);
int nextChildChunkNum = getInt(childAddress);
if (nextChildChunkNum != 0) {
if (!wasInTrie) {
throw describeProblem()
.addProblemAddress("non-null child pointer", childAddress, INT_SIZE) //$NON-NLS-1$
.build("All child pointers should be null for a free chunk that is in the sibling list but" //$NON-NLS-1$
+ " not part of the trie. Problematic chunk number: " + freeBlockChunkNum); //$NON-NLS-1$
}
insertChild(currentParent, nextChildChunkNum);
// Parent all subsequent children under the child that was most similar to the old parent
if (currentParent == parentChunkNum) {
currentParent = nextChildChunkNum;
}
}
}
}
/**
* Returns the chunk number of a free block that contains at least the given number of chunks, or
* 0 if there is no existing contiguous free block containing at least the given number of chunks.
*
* @param numChunks minumum number of chunks desired
* @return the chunk number of a free block containing at least the given number of chunks or 0
* if there is no existing free block containing that many chunks.
*/
private int getFreeBlockFromTrie(int numChunks) {
int currentChunkNum = getInt(FREE_BLOCK_OFFSET);
int resultChunkNum = getSmallestChildNoSmallerThan(currentChunkNum, numChunks);
if (resultChunkNum == 0) {
return 0;
}
// Try not to return the trie node itself if there is a linked list entry available, since unlinking
// something from the linked list is faster than unlinking a trie node.
int nextResultChunkNum = getInt((long) resultChunkNum * CHUNK_SIZE + LargeBlock.NEXT_BLOCK_OFFSET);
if (nextResultChunkNum != 0) {
return nextResultChunkNum;
}
return resultChunkNum;
}
/**
* Given the chunk number of a block somewhere in the free space trie, this returns the smallest
* child in the subtree that is no smaller than the given number of chunks.
*
* @param trieNodeChunkNum chunk number of a block in the free space trie
* @param numChunks desired number of chunks
* @return the chunk number of the first chunk in a contiguous free block containing at least the
* given number of chunks
*/
private int getSmallestChildNoSmallerThan(int trieNodeChunkNum, int numChunks) {
if (trieNodeChunkNum == 0) {
return 0;
}
int currentSize = getBlockHeaderForChunkNum(trieNodeChunkNum);
assert (currentSize >= 0);
int difference = currentSize ^ numChunks;
if (difference == 0) {
return trieNodeChunkNum;
}
int bitMask = Integer.highestOneBit(difference);
int firstDifference = LargeBlock.SIZE_OF_SIZE_FIELD * 8 - Integer.numberOfLeadingZeros(bitMask) - 1;
boolean lookingForSmallerChild = (currentSize > numChunks);
for (int testPosition = firstDifference; testPosition < LargeBlock.ENTRIES_IN_CHILD_TABLE; testPosition++) {
if (((currentSize & bitMask) != 0) == lookingForSmallerChild) {
int nextChildChunkNum = getInt(
(long) trieNodeChunkNum * CHUNK_SIZE + LargeBlock.CHILD_TABLE_OFFSET + (testPosition * INT_SIZE));
int childResultChunkNum = getSmallestChildNoSmallerThan(nextChildChunkNum, numChunks);
if (childResultChunkNum != 0) {
return childResultChunkNum;
}
}
bitMask <<= 1;
}
if (lookingForSmallerChild) {
return trieNodeChunkNum;
} else {
return 0;
}
}
/**
* Link the given unused block into the free block tries. The block does not need to have
* its header filled in already.
*
* @param freeBlockChunkNum chunk number of the start of the block
* @param numChunks number of chunks in the block
*/
private void linkFreeBlockToTrie(int freeBlockChunkNum, int numChunks) {
setBlockHeader(freeBlockChunkNum, numChunks);
long freeBlockAddress = (long) freeBlockChunkNum * CHUNK_SIZE;
Chunk chunk = getChunk(freeBlockAddress);
chunk.clear(freeBlockAddress + LargeBlock.HEADER_SIZE,
LargeBlock.UNALLOCATED_HEADER_SIZE - LargeBlock.HEADER_SIZE);
insertChild(getInt(FREE_BLOCK_OFFSET), freeBlockChunkNum);
}
public void validateFreeSpace() {
validateFreeSpaceLists();
validateFreeSpaceTries();
}
/**
* Performs a self-test on the free space lists used by malloc to check for corruption
*/
private void validateFreeSpaceLists() {
int useDeltas;
for (useDeltas = MIN_BLOCK_DELTAS; useDeltas <= MAX_BLOCK_DELTAS; useDeltas++) {
validateFreeBlocksFor(useDeltas);
}
}
private void verifyNotInFreeSpaceList(long result) {
int useDeltas;
for (useDeltas = MIN_BLOCK_DELTAS; useDeltas <= MAX_BLOCK_DELTAS; useDeltas++) {
int correctSize = useDeltas * BLOCK_SIZE_DELTA;
long block = getFirstBlock(correctSize);
long addressOfPrevBlockPointer = getAddressOfFirstBlockPointer(correctSize);
while (block != 0) {
if (block == result) {
throw describeProblem()
.addProblemAddress("incoming pointer", addressOfPrevBlockPointer, PTR_SIZE) //$NON-NLS-1$
.build("Block " + result //$NON-NLS-1$
+ " was found in the free space list, even though it wasn't free"); //$NON-NLS-1$
}
addressOfPrevBlockPointer = block + BLOCK_NEXT_OFFSET;
long followingBlock = getFreeRecPtr(addressOfPrevBlockPointer);
block = followingBlock;
}
}
int currentChunkNum = getInt(FREE_BLOCK_OFFSET);
if (currentChunkNum == 0) {
return;
}
int targetChunkNum = (int) (result / CHUNK_SIZE);
if (currentChunkNum == targetChunkNum) {
throw describeProblem().build("Block " + result //$NON-NLS-1$
+ " was not supposed to be in the free space list, but was linked as the root of the list"); //$NON-NLS-1$
}
verifyNotInLargeBlockFreeSpaceTrie(targetChunkNum, currentChunkNum, 0);
}
private void verifyNotInLargeBlockFreeSpaceTrie(int targetChunkNum, int chunkNum, int parent) {
long chunkStart = chunkNum * CHUNK_SIZE;
for (int testPosition = 0; testPosition < LargeBlock.ENTRIES_IN_CHILD_TABLE; testPosition++) {
long chunkAddress = chunkStart + LargeBlock.CHILD_TABLE_OFFSET + (testPosition * INT_SIZE);
int nextChildChunkNum = getInt(chunkAddress);
if (nextChildChunkNum == 0) {
continue;
}
if (nextChildChunkNum == targetChunkNum) {
throw describeProblem()
.addProblemAddress("trie child address", chunkAddress, INT_SIZE) //$NON-NLS-1$
.build("Chunk number " + nextChildChunkNum //$NON-NLS-1$
+ " was found in the free space trie even though it was in use"); //$NON-NLS-1$
}
verifyNotInLargeBlockFreeSpaceTrie(targetChunkNum, nextChildChunkNum, chunkNum);
}
}
private void validateFreeBlocksFor(int numberOfDeltas) {
int correctSize = numberOfDeltas * BLOCK_SIZE_DELTA;
long lastBlock = 0;
long block = getFirstBlock(correctSize);
long addressOfPrevBlockPointer = getAddressOfFirstBlockPointer(correctSize);
while (block != 0) {
long measuredLastBlock = getFreeRecPtr(block + BLOCK_PREV_OFFSET);
int blockReportedSize = getShort(block);
long followingBlock = getFreeRecPtr(block + BLOCK_NEXT_OFFSET);
if (measuredLastBlock != lastBlock) {
throw describeProblem()
.addProblemAddress("last block", block + BLOCK_PREV_OFFSET, PTR_SIZE) //$NON-NLS-1$
.addProblemAddress("incoming pointer", addressOfPrevBlockPointer, PTR_SIZE) //$NON-NLS-1$
.build("The free space block (" + block //$NON-NLS-1$
+ ") of size " + correctSize + " had an incorrect prev pointer to " //$NON-NLS-1$//$NON-NLS-2$
+ measuredLastBlock + ", but it should have been pointing to " //$NON-NLS-1$
+ lastBlock);
}
if (blockReportedSize != correctSize) {
throw describeProblem()
.addProblemAddress("block size", block, SHORT_SIZE) //$NON-NLS-1$
.addProblemAddress("incoming pointer", addressOfPrevBlockPointer, PTR_SIZE) //$NON-NLS-1$
.build("A block (" + block + ") of size " + measuredLastBlock //$NON-NLS-1$ //$NON-NLS-2$
+ " was in the free space list for blocks of size " + correctSize); //$NON-NLS-1$
}
addressOfPrevBlockPointer = block + BLOCK_NEXT_OFFSET;
lastBlock = block;
block = followingBlock;
}
}
/**
* Performs a self-test on the free space trie list (used by the large block allocator) to check for corruption
*/
private void validateFreeSpaceTries() {
int currentChunkNum = getInt(FREE_BLOCK_OFFSET);
if (currentChunkNum == 0) {
return;
}
Set<Integer> visited = new HashSet<>();
validateFreeSpaceNode(visited, currentChunkNum, 0);
}
private void validateFreeSpaceNode(Set<Integer> visited, int chunkNum, int parent) {
if (visited.contains(chunkNum)) {
throw describeProblem().build("Chunk " + chunkNum + "(parent = " + parent //$NON-NLS-1$//$NON-NLS-2$
+ " appeared twice in the free space tree"); //$NON-NLS-1$
}
long chunkStart = chunkNum * CHUNK_SIZE;
int parentChunk = getInt(chunkStart + LargeBlock.PARENT_OFFSET);
if (parentChunk != parent) {
throw describeProblem()
.addProblemAddress("parent pointer", chunkStart + LargeBlock.PARENT_OFFSET, Database.INT_SIZE) //$NON-NLS-1$
.build("Chunk " + chunkNum + " has the wrong parent. Expected " + parent //$NON-NLS-1$//$NON-NLS-2$
+ " but found " + parentChunk); //$NON-NLS-1$
}
visited.add(chunkNum);
int numChunks = getBlockHeaderForChunkNum(chunkNum);
for (int testPosition = 0; testPosition < LargeBlock.ENTRIES_IN_CHILD_TABLE; testPosition++) {
long nextChildChunkNumAddress = chunkStart + LargeBlock.CHILD_TABLE_OFFSET + (testPosition * INT_SIZE);
int nextChildChunkNum = getInt(nextChildChunkNumAddress);
if (nextChildChunkNum == 0) {
continue;
}
int nextSize = getBlockHeaderForChunkNum(nextChildChunkNum);
int sizeDifference = nextSize ^ numChunks;
int firstDifference = LargeBlock.SIZE_OF_SIZE_FIELD * 8 - Integer.numberOfLeadingZeros(
Integer.highestOneBit(sizeDifference)) - 1;
if (firstDifference != testPosition) {
IndexExceptionBuilder descriptor = describeProblem();
attachBlockHeaderForChunkNum(descriptor, chunkNum);
attachBlockHeaderForChunkNum(descriptor, nextChildChunkNum);
throw descriptor.build("Chunk " + nextChildChunkNum + " contained an incorrect size of " //$NON-NLS-1$//$NON-NLS-2$
+ nextSize + ". It was at position " + testPosition + " in parent " + chunkNum //$NON-NLS-1$ //$NON-NLS-2$
+ " which had size " + numChunks); //$NON-NLS-1$
}
try {
validateFreeSpaceNode(visited, nextChildChunkNum, chunkNum);
} catch (IndexException e) {
describeProblem()
.addProblemAddress("child pointer from parent " + chunkNum, nextChildChunkNumAddress, //$NON-NLS-1$
Database.INT_SIZE)
.attachTo(e);
throw e;
}
}
}
/**
* Adds the given child block to the given parent subtree of the free space trie. Any existing
* subtree under the given child block will be retained.
*
* @param parentChunkNum root of the existing tree, or 0 if the child is going to be the new root
* @param newChildChunkNum the new child to insert
*/
private void insertChild(int parentChunkNum, int newChildChunkNum) {
if (parentChunkNum == 0) {
putInt((long) newChildChunkNum * CHUNK_SIZE + LargeBlock.PARENT_OFFSET, parentChunkNum);
putInt(FREE_BLOCK_OFFSET, newChildChunkNum);
return;
}
int numChunks = getBlockHeaderForChunkNum(newChildChunkNum);
for (;;) {
int currentSize = getBlockHeaderForChunkNum(parentChunkNum);
int difference = currentSize ^ numChunks;
if (difference == 0) {
// The newly added item is exactly the same size as this trie node
insertFreeBlockAfter(parentChunkNum, newChildChunkNum);
return;
}
int firstDifference = LargeBlock.SIZE_OF_SIZE_FIELD * 8 - Integer.numberOfLeadingZeros(difference) - 1;
long locationOfChildPointer = (long) parentChunkNum * CHUNK_SIZE + LargeBlock.CHILD_TABLE_OFFSET
+ (firstDifference * INT_SIZE);
int childChunkNum = getInt(locationOfChildPointer);
if (childChunkNum == 0) {
putInt(locationOfChildPointer, newChildChunkNum);
putInt((long) newChildChunkNum * CHUNK_SIZE + LargeBlock.PARENT_OFFSET, parentChunkNum);
return;
}
parentChunkNum = childChunkNum;
}
}
/**
* Adds the given block to the linked list of equally-sized free chunks in the free space trie.
* Both chunks must be unused, must be the same size, and the previous chunk must already
* be linked into the free space trie. The newly-added chunk must not have any children.
*
* @param prevChunkNum chunk number of previous block in the existing list
* @param newChunkNum new chunk to be added to the list
*/
private void insertFreeBlockAfter(int prevChunkNum, int newChunkNum) {
long prevChunkAddress = (long) prevChunkNum * CHUNK_SIZE;
int nextChunkNum = getInt(prevChunkAddress + LargeBlock.NEXT_BLOCK_OFFSET);
long nextChunkAddress = (long) nextChunkNum * CHUNK_SIZE;
long newLockAddress = (long) newChunkNum * CHUNK_SIZE;
putInt(prevChunkAddress + LargeBlock.NEXT_BLOCK_OFFSET, newChunkNum);
if (nextChunkNum != 0) {
putInt(nextChunkAddress + LargeBlock.PREV_BLOCK_OFFSET, newChunkNum);
}
putInt(newLockAddress + LargeBlock.PREV_BLOCK_OFFSET, prevChunkNum);
putInt(newLockAddress + LargeBlock.NEXT_BLOCK_OFFSET, nextChunkNum);
}
/**
* Returns the chunk number of the chunk at the start of a block, given the
* chunk number of the chunk at the start of the following block.
*
* @param chunkNum the chunk number of the chunk immediately following the
* chunk being queried
* @return the chunk number of the chunk at the start of the previous block
*/
private int getFirstChunkOfBlockBefore(int chunkNum) {
int blockChunks = Math.abs(getBlockFooterForChunkBefore(chunkNum));
return chunkNum - blockChunks;
}
/**
* Sets the block header and footer for the given range of chunks which make
* up a contiguous block.
*
* @param firstChunkNum chunk number of the first chunk in the block
* @param headerContent the content of the header. Its magnitude is the number of
* chunks in the block. It is positive if the chunk is free and negative if
* the chunk is in use.
*/
private void setBlockHeader(int firstChunkNum, int headerContent) {
assert headerContent != 0;
assert firstChunkNum < this.fChunksUsed;
int numBlocks = Math.abs(headerContent);
long firstChunkAddress = firstChunkNum * CHUNK_SIZE;
putInt(firstChunkAddress, headerContent);
putInt(firstChunkAddress + (numBlocks * CHUNK_SIZE) - LargeBlock.FOOTER_SIZE, headerContent);
}
/**
* Returns the size of the block (in number of chunks) starting at the given address. The return value is positive
* if the block is free and negative if the block is allocated.
*/
private int getBlockHeaderForChunkNum(int firstChunkNum) {
if (firstChunkNum >= this.fChunksUsed) {
return 0;
}
return getInt((long) firstChunkNum * CHUNK_SIZE);
}
private void attachBlockHeaderForChunkNum(IndexExceptionBuilder builder, int firstChunkNum) {
if (firstChunkNum >= this.fChunksUsed) {
return;
}
builder.addProblemAddress("block header for chunk " + firstChunkNum, ((long) firstChunkNum * CHUNK_SIZE), //$NON-NLS-1$
Database.INT_SIZE);
}
/**
* Returns the size of the block (in number of chunks), given the (non-inclusive) address that the block ends at.
* The return value is positive if the block is free and negative if the block is allocated.
*/
private int getBlockFooterForChunkBefore(int chunkNum) {
if (chunkNum < 2) {
// Don't report the database header as a normal chunk.
return 0;
}
return getInt((long) chunkNum * CHUNK_SIZE - LargeBlock.FOOTER_SIZE);
}
private int createNewChunks(int numChunks) throws IndexException {
assert this.fExclusiveLock;
synchronized (this.fCache) {
final int firstChunkIndex = this.fChunksUsed;
final int lastChunkIndex = firstChunkIndex + numChunks - 1;
final Chunk lastChunk = new Chunk(this, lastChunkIndex);
if (lastChunkIndex >= this.fChunks.length) {
int increment = Math.max(1024, this.fChunks.length / 20);
int newNumChunks = Math.max(lastChunkIndex + 1, this.fChunks.length + increment);
Chunk[] newChunks = new Chunk[newNumChunks];
System.arraycopy(this.fChunks, 0, newChunks, 0, this.fChunks.length);
this.fChunks = newChunks;
}
this.fChunksUsed = lastChunkIndex + 1;
if (DEBUG_PAGE_CACHE) {
System.out.println("CHUNK " + lastChunk.fSequenceNumber + ": inserted into vector - instance " //$NON-NLS-1$//$NON-NLS-2$
+ System.identityHashCode(lastChunk));
}
this.fChunks[lastChunkIndex] = lastChunk;
this.fMostRecentlyFetchedChunk = lastChunk;
lastChunk.makeDirty();
this.fCache.add(lastChunk);
long result = (long) firstChunkIndex * CHUNK_SIZE;
/*
* Non-dense pointers are at most 31 bits dense pointers are at most 35 bits Check the sizes here and throw
* an exception if the address is too large. By throwing the IndexException with the special status, the
* indexing operation should be stopped. This is desired since generally, once the max size is exceeded,
* there are lots of errors.
*/
long endAddress = result + ((long) numChunks * CHUNK_SIZE);
if (endAddress > MAX_DB_SIZE) {
Object bindings[] = { this.getLocation().getAbsolutePath(), MAX_DB_SIZE };
throw new IndexException(new Status(IStatus.ERROR, Package.PLUGIN_ID, Package.STATUS_DATABASE_TOO_LARGE,
NLS.bind("Database too large! Address = " + endAddress + ", max size = " + MAX_DB_SIZE, //$NON-NLS-1$ //$NON-NLS-2$
bindings), null));
}
return firstChunkIndex;
}
}
private long getAddressOfFirstBlockPointer(int blockSize) {
return MALLOC_TABLE_OFFSET + (blockSize / BLOCK_SIZE_DELTA - MIN_BLOCK_DELTAS) * INT_SIZE;
}
/**
* @param blockSize (must be a multiple of BLOCK_SIZE_DELTA)
*/
private long getFirstBlock(int blockSize) throws IndexException {
assert this.fLocked;
return this.fHeaderChunk.getFreeRecPtr(getAddressOfFirstBlockPointer(blockSize));
}
private void setFirstBlock(int blockSize, long block) throws IndexException {
assert this.fExclusiveLock;
this.fHeaderChunk.putFreeRecPtr(getAddressOfFirstBlockPointer(blockSize), block);
}
private void removeBlock(Chunk chunk, int blocksize, long block) throws IndexException {
assert this.fExclusiveLock;
long prevblock = chunk.getFreeRecPtr(block + BLOCK_PREV_OFFSET);
long nextblock = chunk.getFreeRecPtr(block + BLOCK_NEXT_OFFSET);
if (prevblock != 0) {
putFreeRecPtr(prevblock + BLOCK_NEXT_OFFSET, nextblock);
} else { // We were the head.
setFirstBlock(blocksize, nextblock);
}
if (nextblock != 0)
putFreeRecPtr(nextblock + BLOCK_PREV_OFFSET, prevblock);
}
private void addBlock(Chunk chunk, int blocksize, long block) throws IndexException {
assert this.fExclusiveLock;
// Mark our size
chunk.putShort(block, (short) blocksize);
// Add us to the head of the list.
long prevfirst = getFirstBlock(blocksize);
chunk.putFreeRecPtr(block + BLOCK_PREV_OFFSET, 0);
chunk.putFreeRecPtr(block + BLOCK_NEXT_OFFSET, prevfirst);
if (prevfirst != 0)
putFreeRecPtr(prevfirst + BLOCK_PREV_OFFSET, block);
setFirstBlock(blocksize, block);
}
/**
* Free an allocated block.
*
* @param address
* memory address to be freed
* @param poolId
* the same ID that was previously passed into malloc when allocating this memory address
*/
public void free(long address, short poolId) throws IndexException {
getLog().start(this.freeTag);
try {
assert this.fExclusiveLock;
if (address == 0) {
return;
}
long blockSize;
long block = address - BLOCK_HEADER_SIZE;
Chunk chunk = getChunk(block);
blockSize = -chunk.getShort(block);
// We use a block size of 0 to indicate a large block that fills a range of chunks
if (blockSize == 0) {
int offsetIntoChunk = (int) (address % CHUNK_SIZE);
assert offsetIntoChunk == LargeBlock.HEADER_SIZE + BLOCK_HEADER_SIZE;
// Deallocating a large block
// This was a large block. It uses a sequence of full chunks.
int chunkNum = (int) (address / CHUNK_SIZE);
int numChunks = -getBlockHeaderForChunkNum(chunkNum);
if (numChunks < 0) {
IndexExceptionBuilder builder = describeProblem();
if (chunkNum < this.fChunksUsed) {
builder.addProblemAddress("block header", (long) chunkNum * CHUNK_SIZE, INT_SIZE); //$NON-NLS-1$
}
throw builder.build("Already freed large block " + address); //$NON-NLS-1$
}
blockSize = (long) numChunks * CHUNK_SIZE;
this.log.recordFree(address, (int)(blockSize - BLOCK_HEADER_SIZE));
freeLargeChunk(chunkNum, numChunks);
} else {
// Deallocating a normal block
// TODO Look for opportunities to merge small blocks
if (blockSize < 0) {
throw describeProblem()
.addProblemAddress("block size", block, SHORT_SIZE) //$NON-NLS-1$
.build("Already freed record " + address); //$NON-NLS-1$
}
this.log.recordFree(address, (int)(blockSize - BLOCK_HEADER_SIZE));
int offset = Chunk.recPtrToIndex(address);
if (offset + blockSize > CHUNK_SIZE) {
throw describeProblem()
.addProblemAddress("block size", block, SHORT_SIZE) //$NON-NLS-1$
.build("Attempting to free chunk of impossible size. The block at address " //$NON-NLS-1$
+ address + " in chunk " + chunk.fSequenceNumber + " offset " + offset //$NON-NLS-1$//$NON-NLS-2$
+ " can't be as large as " //$NON-NLS-1$
+ blockSize + " bytes since that would make it extend beyond the end of the chunk"); //$NON-NLS-1$
}
addBlock(chunk, (int) blockSize, block);
}
if (DEBUG_FREE_SPACE) {
periodicValidateFreeSpace();
}
this.freed += blockSize;
this.memoryUsage.recordFree(poolId, blockSize);
} finally {
getLog().end(this.freeTag);
}
}
/**
* Periodically performs validation of the free space in the database. Validation is very expensive, so the
* validation period uses exponential falloff so validations happen less and less frequently over
* time. Returns true iff validation happened on this iteration.
*/
private boolean periodicValidateFreeSpace() {
this.validateCounter++;
if (this.validateCounter > this.nextValidation) {
validateFreeSpace();
this.nextValidation = this.validateCounter * 2;
return true;
}
return false;
}
private void freeLargeChunk(int chunkNum, int numChunks) {
assert chunkNum > 0;
assert numChunks > 0;
int prevBlockHeader = getBlockFooterForChunkBefore(chunkNum);
int nextBlockChunkNum = chunkNum + numChunks;
int nextBlockHeader = getBlockHeaderForChunkNum(nextBlockChunkNum);
// If the previous block is unused, merge with it
if (prevBlockHeader > 0) {
int prevBlockChunkNum = getFirstChunkOfBlockBefore(chunkNum);
unlinkFreeBlock(prevBlockChunkNum);
chunkNum = prevBlockChunkNum;
numChunks += prevBlockHeader;
}
// If the next block is unused, merge with it
if (nextBlockHeader > 0) {
unlinkFreeBlock(nextBlockChunkNum);
numChunks += nextBlockHeader;
}
// Block merging is done. Now reinsert the merged block into the free space trie
linkFreeBlockToTrie(chunkNum, numChunks);
}
public void putByte(long offset, byte value) throws IndexException {
getChunk(offset).putByte(offset, value);
}
public byte getByte(long offset) throws IndexException {
return getChunk(offset).getByte(offset);
}
public void putInt(long offset, int value) throws IndexException {
getChunk(offset).putInt(offset, value);
}
public int getInt(long offset) throws IndexException {
return getChunk(offset).getInt(offset);
}
public void putRecPtr(long offset, long value) throws IndexException {
getChunk(offset).putRecPtr(offset, value);
}
public long getRecPtr(long offset) throws IndexException {
return getChunk(offset).getRecPtr(offset);
}
private void putFreeRecPtr(long offset, long value) throws IndexException {
getChunk(offset).putFreeRecPtr(offset, value);
}
private long getFreeRecPtr(long offset) throws IndexException {
return getChunk(offset).getFreeRecPtr(offset);
}
public void put3ByteUnsignedInt(long offset, int value) throws IndexException {
getChunk(offset).put3ByteUnsignedInt(offset, value);
}
public int get3ByteUnsignedInt(long offset) throws IndexException {
return getChunk(offset).get3ByteUnsignedInt(offset);
}
public void putShort(long offset, short value) throws IndexException {
getChunk(offset).putShort(offset, value);
}
public short getShort(long offset) throws IndexException {
return getChunk(offset).getShort(offset);
}
public void putLong(long offset, long value) throws IndexException {
getChunk(offset).putLong(offset, value);
}
public void putDouble(long offset, double value) throws IndexException {
getChunk(offset).putDouble(offset, value);
}
public void putFloat(long offset, float value) throws IndexException {
getChunk(offset).putFloat(offset, value);
}
public long getLong(long offset) throws IndexException {
return getChunk(offset).getLong(offset);
}
public double getDouble(long offset) throws IndexException {
return getChunk(offset).getDouble(offset);
}
public float getFloat(long offset) throws IndexException {
return getChunk(offset).getFloat(offset);
}
public void putChar(long offset, char value) throws IndexException {
getChunk(offset).putChar(offset, value);
}
public char getChar(long offset) throws IndexException {
return getChunk(offset).getChar(offset);
}
public void clearBytes(long offset, int byteCount) throws IndexException {
getChunk(offset).clear(offset, byteCount);
}
public void putBytes(long offset, byte[] data, int len) throws IndexException {
getChunk(offset).put(offset, data, len);
}
public void putBytes(long offset, byte[] data, int dataPos, int len) throws IndexException {
getChunk(offset).put(offset, data, dataPos, len);
}
public void getBytes(long offset, byte[] data) throws IndexException {
getChunk(offset).get(offset, data);
}
public void getBytes(long offset, byte[] data, int dataPos, int len) throws IndexException {
getChunk(offset).get(offset, data, dataPos, len);
}
public IString newString(String string) throws IndexException {
return newString(string.toCharArray());
}
public IString newString(char[] chars) throws IndexException {
int len= chars.length;
int bytelen;
final boolean useBytes = useBytes(chars);
if (useBytes) {
bytelen= len;
} else {
bytelen= 2 * len;
}
if (bytelen > ShortString.MAX_BYTE_LENGTH) {
return new LongString(this, chars, useBytes);
} else {
return new ShortString(this, chars, useBytes);
}
}
private boolean useBytes(char[] chars) {
for (char c : chars) {
if ((c & 0xff00) != 0)
return false;
}
return true;
}
public IString getString(long offset) throws IndexException {
final int l = getInt(offset);
int bytelen= l < 0 ? -l : 2 * l;
if (bytelen > ShortString.MAX_BYTE_LENGTH) {
return new LongString(this, offset);
}
return new ShortString(this, offset);
}
public long getDatabaseSize() {
return (long) this.fChunksUsed * CHUNK_SIZE;
}
/**
* Returns the number of bytes freed by {@link #free(long, short)} since this {@link Database} instance was
* instantiated. Intended for use in unit tests.
*/
public long getBytesFreed() {
return this.freed;
}
/**
* Returns the number of bytes allocated by {@link #malloc(long, short)} since this {@link Database} instance was
* instantiated. Intended for use in unit tests.
*/
public long getBytesAllocated() {
return this.malloced;
}
/**
* For debugging purposes, only.
*/
public void reportFreeBlocks() throws IndexException {
System.out.println("Allocated size: " + formatByteString(getDatabaseSize())); //$NON-NLS-1$
System.out.println("malloc'ed: " + formatByteString(this.malloced)); //$NON-NLS-1$
System.out.println("free'd: " + formatByteString(this.freed)); //$NON-NLS-1$
System.out.println("wasted: " + formatByteString((getDatabaseSize() - (this.malloced - this.freed)))); //$NON-NLS-1$
System.out.println("Free blocks"); //$NON-NLS-1$
for (int bs = MIN_BLOCK_DELTAS*BLOCK_SIZE_DELTA; bs <= CHUNK_SIZE; bs += BLOCK_SIZE_DELTA) {
int count = 0;
long block = getFirstBlock(bs);
while (block != 0) {
++count;
block = getFreeRecPtr(block + BLOCK_NEXT_OFFSET);
}
if (count != 0)
System.out.println("Block size: " + bs + "=" + count); //$NON-NLS-1$ //$NON-NLS-2$
}
}
/**
* Closes the database.
* <p>
* The behavior of any further calls to the Database is undefined
* @throws IndexException
*/
public void close() throws IndexException {
assert this.fExclusiveLock;
flush();
removeChunksFromCache();
this.log.clear();
// Chunks have been removed from the cache, so we are fine.
this.fHeaderChunk.clear(0, CHUNK_SIZE);
this.memoryUsage.refresh();
this.fHeaderChunk.fDirty= false;
this.dirtyChunkSet.clear();
this.fChunks= new Chunk[] { null };
this.fChunksUsed = this.fChunks.length;
try {
this.fFile.close();
} catch (IOException e) {
throw new IndexException(new DBStatus(e));
}
}
/**
* This method is public for testing purposes only.
*/
public File getLocation() {
return this.fLocation;
}
/**
* Called from any thread via the cache, protected by {@link #fCache}.
*/
void checkIfChunkReleased(final Chunk chunk) {
if (!chunk.fDirty && chunk.fCacheIndex < 0) {
if (DEBUG_PAGE_CACHE) {
System.out.println("CHUNK " + chunk.fSequenceNumber //$NON-NLS-1$
+ ": removing from vector in releaseChunk - instance " + System.identityHashCode(chunk)); //$NON-NLS-1$
}
this.fChunks[chunk.fSequenceNumber]= null;
}
}
void chunkDirtied(final Chunk chunk) {
if (chunk.fSequenceNumber < NUM_HEADER_CHUNKS) {
return;
}
this.dirtyChunkSet.add(chunk);
}
void chunkCleaned(final Chunk chunk) {
if (chunk.fSequenceNumber < NUM_HEADER_CHUNKS) {
return;
}
this.dirtyChunkSet.remove(chunk);
checkIfChunkReleased(chunk);
}
/**
* Returns the cache used for this database.
* @since 4.0
*/
public ChunkCache getChunkCache() {
return this.fCache;
}
/**
* Asserts that database is used by one thread exclusively. This is necessary when doing
* write operations.
*/
public void setExclusiveLock() {
this.fExclusiveLock= true;
this.fLocked= true;
}
public void setLocked(boolean val) {
this.fLocked= val;
}
public void giveUpExclusiveLock() {
this.fExclusiveLock = false;
}
public boolean flush() throws IndexException {
boolean wasInterrupted = false;
assert this.fLocked;
ArrayList<Chunk> dirtyChunks= new ArrayList<>();
synchronized (this.fCache) {
dirtyChunks.addAll(this.dirtyChunkSet);
}
sortBySequenceNumber(dirtyChunks);
long startTime = System.currentTimeMillis();
// Also handles header chunk.
wasInterrupted = flushAndUnlockChunks(dirtyChunks, true) || wasInterrupted;
long elapsedTime = System.currentTimeMillis() - startTime;
this.totalFlushTime += elapsedTime;
return wasInterrupted;
}
private void sortBySequenceNumber(ArrayList<Chunk> dirtyChunks) {
dirtyChunks.sort((a, b) -> {return a.fSequenceNumber - b.fSequenceNumber;});
}
/**
* Interrupting the thread with {@link Thread#interrupt()} won't interrupt the write. Returns true iff an attempt
* was made to interrupt the thread with {@link Thread#interrupt()}.
*
* @throws IndexException
*/
private boolean flushAndUnlockChunks(final ArrayList<Chunk> dirtyChunks, boolean isComplete) throws IndexException {
boolean wasInterrupted = false;
assert !Thread.holdsLock(this.fCache);
final boolean haveDirtyChunks = !dirtyChunks.isEmpty();
if (haveDirtyChunks || this.fHeaderChunk.fDirty) {
wasInterrupted = markFileIncomplete() || wasInterrupted;
}
if (haveDirtyChunks) {
double desiredWriteBytesPerMs = Database.MIN_BYTES_PER_MILLISECOND;
synchronized (this.fCache) {
if (this.cacheMisses > 100) {
double measuredReadBytesPerMs = getAverageReadBytesPerMs();
if (measuredReadBytesPerMs > 0) {
desiredWriteBytesPerMs = measuredReadBytesPerMs / 2;
}
}
}
desiredWriteBytesPerMs = Math.max(desiredWriteBytesPerMs, Database.MIN_BYTES_PER_MILLISECOND);
ChunkWriter writer = new ChunkWriter(WRITE_BUFFER_SIZE, desiredWriteBytesPerMs, this::write);
try {
for (Chunk chunk : dirtyChunks) {
if (chunk.fDirty) {
boolean wasCanceled = false;
if (DEBUG_PAGE_CACHE) {
System.out.println("CHUNK " + chunk.fSequenceNumber + ": flushing - instance " //$NON-NLS-1$//$NON-NLS-2$
+ System.identityHashCode(chunk));
}
byte[] nextBytes;
synchronized (this.fCache) {
nextBytes = chunk.getBytes();
chunk.fDirty = false;
chunkCleaned(chunk);
}
wasCanceled = writer.write((long) chunk.fSequenceNumber * Database.CHUNK_SIZE, nextBytes);
wasInterrupted = wasCanceled || wasInterrupted;
}
}
writer.flush();
synchronized (this.fCache) {
this.pageWritesBytes += writer.getBytesWritten();
this.totalWriteTimeMs += writer.getTotalWriteTimeMs();
}
} catch (IOException e) {
throw new IndexException(new DBStatus(e));
}
}
if (isComplete) {
if (this.fHeaderChunk.fDirty || this.fIsMarkedIncomplete) {
this.fHeaderChunk.putInt(VERSION_OFFSET, this.fVersion);
wasInterrupted = this.fHeaderChunk.flush() || wasInterrupted;
this.fIsMarkedIncomplete= false;
}
}
return wasInterrupted;
}
private boolean markFileIncomplete() throws IndexException {
boolean wasInterrupted = false;
if (!this.fIsMarkedIncomplete) {
this.fIsMarkedIncomplete= true;
try {
final ByteBuffer buf= ByteBuffer.wrap(new byte[4]);
wasInterrupted = performUninterruptableWrite(() -> this.fFile.getChannel().write(buf, 0));
this.bytesWritten += 4;
} catch (IOException e) {
throw new IndexException(new DBStatus(e));
}
}
return wasInterrupted;
}
public void resetCacheCounters() {
this.cacheHits = 0;
this.cacheMisses = 0;
this.bytesWritten = 0;
this.totalFlushTime = 0;
this.pageWritesBytes = 0;
this.totalWriteTimeMs = 0;
this.totalReadTimeMs = 0;
}
public long getBytesWritten() {
return this.bytesWritten;
}
public double getAverageReadBytesPerMs() {
long reads = this.cacheMisses;
long time = this.totalReadTimeMs;
if (time == 0) {
return 0;
}
return (double)(reads * CHUNK_SIZE) / (double) time;
}
public double getAverageWriteBytesPerMs() {
long time = this.totalWriteTimeMs;
long writes = this.pageWritesBytes;
return ((double) writes / (double) time);
}
public long getBytesRead() {
return this.cacheMisses * CHUNK_SIZE;
}
public long getCacheHits() {
return this.cacheHits;
}
public long getCacheMisses() {
return this.cacheMisses;
}
public long getCumulativeFlushTimeMs() {
return this.totalFlushTime;
}
public long getSizeBytes() throws IOException {
return this.fFile.length();
}
public int getChunkCount() {
return this.fChunksUsed;
}
/**
* A Record Pointer is a pointer as returned by Database.malloc().
* This is a pointer to a block + BLOCK_HEADER_SIZE.
*/
public static void putRecPtr(final long value, byte[] buffer, int idx) {
final int denseValue = value == 0 ? 0 : Chunk.compressFreeRecPtr(value - BLOCK_HEADER_SIZE);
Chunk.putInt(denseValue, buffer, idx);
}
/**
* A Record Pointer is a pointer as returned by Database.malloc().
* This is a pointer to a block + BLOCK_HEADER_SIZE.
*/
public static long getRecPtr(byte[] buffer, final int idx) {
int value = Chunk.getInt(buffer, idx);
long address = Chunk.expandToFreeRecPtr(value);
return address != 0 ? (address + BLOCK_HEADER_SIZE) : address;
}
public MemoryStats getMemoryStats() {
return this.memoryUsage;
}
/**
* Returns the number of bytes that can fit in the payload of the given number of chunks.
*/
public static long getBytesThatFitInChunks(int numChunks) {
return CHUNK_SIZE * (long) numChunks - LargeBlock.HEADER_SIZE - LargeBlock.FOOTER_SIZE - BLOCK_HEADER_SIZE;
}
/**
* Returns the number of chunks needed to fit the given number of bytes of payload.
*/
public static int getChunksNeededForBytes(long datasize) {
return divideRoundingUp(datasize + BLOCK_HEADER_SIZE + LargeBlock.HEADER_SIZE + LargeBlock.FOOTER_SIZE,
CHUNK_SIZE);
}
public ChunkCache getCache() {
return this.fCache;
}
public int getDirtyChunkCount() {
return this.dirtyChunkSet.size();
}
public static String formatByteString(long valueInBytes) {
final double MB = 1024 * 1024;
double value = valueInBytes;
String suffix = "B"; //$NON-NLS-1$
if (value > 1024) {
suffix = "MiB"; //$NON-NLS-1$
value /= MB;
}
DecimalFormat mbFormat = new DecimalFormat("#0.###"); //$NON-NLS-1$
return mbFormat.format(value) + suffix;
}
public ChunkStats getChunkStats() {
synchronized (this.fCache) {
int count = 0;
int dirtyChunks = 0;
int nonDirtyChunksNotInCache = 0;
for (Chunk next : this.fChunks) {
if (next != null) {
count++;
if (next.fDirty) {
dirtyChunks++;
} else if (next.fCacheIndex < 0) {
nonDirtyChunksNotInCache++;
}
}
}
return new ChunkStats(this.fChunks.length, count, dirtyChunks, nonDirtyChunksNotInCache);
}
}
public IndexExceptionBuilder describeProblem() {
return new IndexExceptionBuilder(this);
}
}