/*
*
*
* Portions Copyright 2000-2007 Sun Microsystems, Inc. All Rights
* Reserved. Use is subject to license terms.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 only, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License version 2 for more details (a copy is
* included at /legal/license.txt).
*
* You should have received a copy of the GNU General Public License
* version 2 along with this work; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 or visit www.sun.com if you need additional
* information or have any questions.
*
* Copyright 2000 Motorola, Inc. All Rights Reserved.
* This notice does not imply publication.
*/
package com.sun.midp.rms;
import java.io.IOException;
import javax.microedition.rms.*;
import com.sun.midp.security.Permissions;
import com.sun.midp.security.SecurityToken;
import com.sun.midp.log.Logging;
import com.sun.midp.log.LogChannels;
/**
* A class implementing a MIDP a record store.
*/
public class RecordStoreImpl implements AbstractRecordStoreImpl {
/** used to compact the records of the record store */
private byte[] compactBuffer = new byte[COMPACT_BUFFER_SIZE];
/**
* Internal indicator for AUTHMODE_ANY with read only access
* AUTHMODE_ANY_RO has a value of 2.
*/
final static int AUTHMODE_ANY_RO = 2;
/** unique id for suite that owns this record store */
int suiteId;
/** lock used to synchronize this record store */
Object rsLock;
/** data block header stored here */
byte[] dbHeader;
/** record store index */
private RecordStoreIndex dbIndex;
/** record store data */
private RecordStoreFile dbFile;
/**
* Deletes the named record store. MIDlet suites are only allowed
* to delete their own record stores. If the named record store is
* open (by a MIDlet in this suite or a MIDlet in a different
* MIDlet suite) when this method is called, a
* RecordStoreException will be thrown. If the named record store
* does not exist a RecordStoreNotFoundException will be
* thrown. Calling this method does NOT result in recordDeleted
* calls to any registered listeners of this RecordStore.
*
* @param token security token for authorization
* @param suiteId ID of the MIDlet suite that owns the record store
* @param recordStoreName the MIDlet suite unique record store to
* delete
*
* @exception RecordStoreException if a record store-related
* exception occurred
* @exception RecordStoreNotFoundException if the record store
* could not be found
*/
public static void deleteRecordStore(SecurityToken token,
int suiteId,
String recordStoreName)
throws RecordStoreException, RecordStoreNotFoundException {
token.checkIfPermissionAllowed(Permissions.MIDP);
// check if file exists and delete it
if (RecordStoreUtil.exists(suiteId, recordStoreName,
RecordStoreFile.DB_EXTENSION)) {
boolean success = RecordStoreIndex.deleteIndex(
suiteId, recordStoreName);
RecordStoreUtil.deleteFile(suiteId,
recordStoreName, RecordStoreFile.DB_EXTENSION);
if (!success) {
throw new RecordStoreException("deleteRecordStore " +
"failed");
}
} else {
throw new RecordStoreNotFoundException("deleteRecordStore " +
"error: file " +
"not found");
}
}
/**
* Open (and possibly create) a record store associated with the
* given MIDlet suite. If this method is called by a MIDlet when
* the record store is already open by a MIDlet in the MIDlet suite,
* this method returns a reference to the same RecordStoreImpl object.
*
* @param token security token for authorization
* @param suiteId ID of the MIDlet suite that owns the record store
* @param recordStoreName the MIDlet suite unique name for the
* record store, consisting of between one and 32 Unicode
* characters inclusive.
* @param createIfNecessary if true, the record store will be
* created if necessary
*
* @return <code>RecordStore</code> object for the record store
*
* @exception RecordStoreException if a record store-related
* exception occurred
* @exception RecordStoreNotFoundException if the record store
* could not be found
* @exception RecordStoreFullException if the operation cannot be
* completed because the record store is full
* @exception IllegalArgumentException if
* recordStoreName is invalid
*/
public static RecordStoreImpl openRecordStore(SecurityToken token,
int suiteId,
String recordStoreName,
boolean createIfNecessary)
throws RecordStoreException, RecordStoreFullException,
RecordStoreNotFoundException {
token.checkIfPermissionAllowed(Permissions.MIDP);
return new RecordStoreImpl(suiteId, recordStoreName,
createIfNecessary);
}
/**
* Changes the access mode for this RecordStore. The authorization
* mode choices are:
*
* <ul>
* <li><code>AUTHMODE_PRIVATE</code> - Only allows the MIDlet
* suite that created the RecordStore to access it. This
* case behaves identically to
* <code>openRecordStore(recordStoreName,
* createIfNecessary)</code>.</li>
* <li><code>AUTHMODE_ANY</code> - Allows any MIDlet to access the
* RecordStore. Note that this makes your recordStore
* accessible by any other MIDlet on the device. This
* could have privacy and security issues depending on
* the data being shared. Please use carefully.</li>
* </ul>
*
* <p>The owning MIDlet suite may always access the RecordStore and
* always has access to write and update the store. Only the
* owning MIDlet suite can change the mode of a RecordStore.</p>
*
* @param authmode the mode under which to check or create access.
* Must be one of AUTHMODE_PRIVATE or AUTHMODE_ANY.
* @param writable true if the RecordStore is to be writable by
* other MIDlet suites that are granted access
*
* @exception RecordStoreException if a record store-related
* exception occurred
* @exception SecurityException if this MIDlet Suite is not
* allowed to change the mode of the RecordStore
* @exception IllegalArgumentException if authmode is invalid
*/
public void setMode(int authmode, boolean writable)
throws RecordStoreException {
synchronized (rsLock) {
int newAuthMode = authmode;
if ((authmode == RecordStore.AUTHMODE_ANY) &&
(writable == false)) {
newAuthMode = AUTHMODE_ANY_RO;
}
RecordStoreUtil.putInt(newAuthMode, dbHeader, RS1_AUTHMODE);
try {
// write out the changes to the db header
dbFile.seek(RS1_AUTHMODE);
dbFile.write(dbHeader, RS1_AUTHMODE, 4);
// dbFile.commitWrite();
} catch (java.io.IOException ioe) {
throw new RecordStoreException("error writing record " +
"store attributes");
}
}
}
/**
* This method is called when the MIDlet requests to have the
* record store closed. Note that the record store will not
* actually be closed until closeRecordStore() is called as many
* times as openRecordStore() was called. In other words, the
* MIDlet needs to make a balanced number of close calls as open
* calls before the record store is closed.
*
* <p>When the record store is closed, all listeners are removed
* and all RecordEnumerations associated with it become invalid.
* If the MIDlet attempts to perform
* operations on the RecordStore object after it has been closed,
* the methods will throw a RecordStoreNotOpenException.
*
* @exception RecordStoreNotOpenException if the record store is
* not open
* @exception RecordStoreException if a different record
* store-related exception occurred
*/
public void closeRecordStore()
throws RecordStoreNotOpenException, RecordStoreException {
synchronized (rsLock) {
try {
// close native fd
compactRecords(); // compact before close
dbFile.close();
dbIndex.close();
} catch (java.io.IOException ioe) {
throw new RecordStoreException("error closing .db file. "
+ ioe);
} finally {
dbFile = null;
}
}
}
/**
* Returns an array of the names of record stores owned by the
* MIDlet suite. Note that if the MIDlet suite does not
* have any record stores, this function will return null.
*
* The order of RecordStore names returned is implementation
* dependent.
*
* @param token security token for authorization
* @param suiteId ID of the MIDlet suite that owns the record store
*
* @return array of the names of record stores owned by the
* MIDlet suite. Note that if the MIDlet suite does not
* have any record stores, this function will return null.
*/
public static String[] listRecordStores(SecurityToken token,
int suiteId) {
token.checkIfPermissionAllowed(Permissions.MIDP);
return RecordStoreFile.listRecordStores(suiteId);
}
/**
* Get the authorization mode for this record store.
*
* @return authorization mode
*/
public int getAuthMode() {
return RecordStoreUtil.getInt(dbHeader, RS1_AUTHMODE);
}
/**
* Each time a record store is modified (by
* <code>addRecord</code>, <code>setRecord</code>, or
* <code>deleteRecord</code> methods) its <em>version</em> is
* incremented. This can be used by MIDlets to quickly tell if
* anything has been modified.
*
* The initial version number is implementation dependent.
* The increment is a positive integer greater than 0.
* The version number increases only when the RecordStore is updated.
*
* The increment value need not be constant and may vary with each
* update.
*
* @return the current record store version
*/
public int getVersion() throws RecordStoreNotOpenException {
return RecordStoreUtil.getInt(dbHeader, RS4_VERSION);
}
/**
* Returns the number of records currently in the record store.
*
* @return the number of records currently in the record store
*/
public int getNumRecords() {
return RecordStoreUtil.getInt(dbHeader, RS3_NUM_LIVE);
}
/**
* Returns the amount of space, in bytes, that the record store
* occupies. The size returned includes any overhead associated
* with the implementation, such as the data structures
* used to hold the state of the record store, etc.
*
* @return the size of the record store in bytes
*/
public int getSize() {
return DB_HEADER_SIZE + RecordStoreUtil.getInt(dbHeader, RS6_DATA_SIZE);
}
/**
* Returns the amount of additional room (in bytes) available for
* this record store to grow. Note that this is not necessarily
* the amount of extra MIDlet-level data which can be stored,
* as implementations may store additional data structures with
* each record to support integration with native applications,
* synchronization, etc.
*
* @return the amount of additional room (in bytes) available for
* this record store to grow
*/
public int getSizeAvailable() {
int fileSpace = dbFile.spaceAvailable(suiteId) -
BLOCK_HEADER_SIZE - DB_HEADER_SIZE;
int limitSpace = RMSConfig.STORAGE_SUITE_LIMIT -
RecordStoreUtil.getInt(dbHeader, RS6_DATA_SIZE) -
BLOCK_HEADER_SIZE - DB_HEADER_SIZE;
int rv = (fileSpace < limitSpace) ? fileSpace : limitSpace;
return (rv < 0) ? 0 : rv;
}
/**
* Returns the last time the record store was modified, in the
* format used by System.currentTimeMillis().
*
* @return the last time the record store was modified, in the
* format used by System.currentTimeMillis()
*/
public long getLastModified() {
return RecordStoreUtil.getLong(dbHeader, RS5_LAST_MODIFIED);
}
/**
* Returns the recordId of the next record to be added to the
* record store. This can be useful for setting up pseudo-relational
* relationships. That is, if you have two or more
* record stores whose records need to refer to one another, you can
* predetermine the recordIds of the records that will be created
* in one record store, before populating the fields and allocating
* the record in another record store. Note that the recordId returned
* is only valid while the record store remains open and until a call
* to <code>addRecord()</code>.
*
* @return the recordId of the next record to be added to the
* record store
*/
public int getNextRecordID() {
return RecordStoreUtil.getInt(dbHeader, RS2_NEXT_ID);
}
/**
* Adds a new record to the record store. The recordId for this
* new record is returned. This is a blocking atomic operation.
* The record is written to persistent storage before the
* method returns.
*
* @param data the data to be stored in this record. If the record
* is to have zero-length data (no data), this parameter may be
* null.
* @param offset the index into the data buffer of the first
* relevant byte for this record
* @param numBytes the number of bytes of the data buffer to use
* for this record (may be zero)
*
* @return the recordId for the new record
*
* @exception RecordStoreNotOpenException if the record store is
* not open
* @exception RecordStoreException if a different record
* store-related exception occurred
* @exception RecordStoreFullException if the operation cannot be
* completed because the record store has no more room
* @exception SecurityException if the MIDlet has read-only access
* to the RecordStore
*/
public int addRecord(byte[] data, int offset, int numBytes)
throws RecordStoreNotOpenException, RecordStoreException,
RecordStoreFullException {
synchronized (rsLock) {
int recordId = getNextRecordID();
try {
// add a block for this record
addBlock(recordId, data, offset, numBytes);
// update the db header
RecordStoreUtil.putInt(recordId+1, dbHeader, RS2_NEXT_ID);
RecordStoreUtil.putInt(getNumRecords()+1, dbHeader, RS3_NUM_LIVE);
RecordStoreUtil.putInt(getVersion()+1, dbHeader, RS4_VERSION);
RecordStoreUtil.putLong(System.currentTimeMillis(), dbHeader,
RS5_LAST_MODIFIED);
// write out the changes to the db header
dbFile.seek(RS2_NEXT_ID);
dbFile.write(dbHeader, RS2_NEXT_ID, 3*4+8);
// dbFile.commitWrite();
} catch (java.io.IOException ioe) {
throw new RecordStoreException("error writing new record "
+ "data");
}
// Return the new record id
return recordId;
}
}
/**
* The record is deleted from the record store. The recordId for
* this record is NOT reused.
*
* @param recordId the ID of the record to delete
*
* @exception RecordStoreNotOpenException if the record store is
* not open
* @exception InvalidRecordIDException if the recordId is invalid
* @exception RecordStoreException if a general record store
* exception occurs
* @exception SecurityException if the MIDlet has read-only access
* to the RecordStore
*/
public void deleteRecord(int recordId)
throws RecordStoreNotOpenException, InvalidRecordIDException,
RecordStoreException {
synchronized (rsLock) {
try {
byte[] header = new byte[BLOCK_HEADER_SIZE];
int blockOffset = dbIndex.getRecordHeader(recordId, header);
// free the block
freeBlock(blockOffset, header);
// update the db index
dbIndex.deleteRecordIndex(recordId);
// update the db header
RecordStoreUtil.putInt(getNumRecords()-1, dbHeader, RS3_NUM_LIVE);
RecordStoreUtil.putInt(getVersion()+1, dbHeader, RS4_VERSION);
RecordStoreUtil.putLong(System.currentTimeMillis(), dbHeader,
RS5_LAST_MODIFIED);
// save the updated db header
dbFile.seek(RS3_NUM_LIVE);
dbFile.write(dbHeader, RS3_NUM_LIVE, 2*4+8);
// dbFile.commitWrite();
} catch (java.io.IOException ioe) {
throw new RecordStoreException("error updating file after" +
" record deletion");
}
}
}
/**
* Returns the size (in bytes) of the MIDlet data available
* in the given record.
*
* @param recordId the ID of the record to use in this operation
*
* @return the size (in bytes) of the MIDlet data available
* in the given record
*
* @exception RecordStoreNotOpenException if the record store is
* not open
* @exception InvalidRecordIDException if the recordId is invalid
* @exception RecordStoreException if a general record store
* exception occurs
*/
public int getRecordSize(int recordId)
throws RecordStoreNotOpenException, InvalidRecordIDException,
RecordStoreException {
synchronized (rsLock) {
byte[] header = new byte[BLOCK_HEADER_SIZE];
try {
dbIndex.getRecordHeader(recordId, header);
} catch (java.io.IOException ioe) {
throw new RecordStoreException("error reading record data");
}
return RecordStoreUtil.getInt(header, 4);
}
}
/**
* Returns the data stored in the given record.
*
* @param recordId the ID of the record to use in this operation
* @param buffer the byte array in which to copy the data
* @param offset the index into the buffer in which to start copying
*
* @exception RecordStoreNotOpenException if the record store is
* not open
* @exception InvalidRecordIDException if the recordId is invalid
* @exception RecordStoreException if a general record store
* exception occurs
* @exception ArrayIndexOutOfBoundsException if the record is
* larger than the buffer supplied
*
* @return the number of bytes copied into the buffer, starting at
* index <code>offset</code>
* @see #setRecord
*/
public int getRecord(int recordId, byte[] buffer, int offset)
throws RecordStoreNotOpenException, InvalidRecordIDException,
RecordStoreException {
synchronized (rsLock) {
try {
byte[] header = new byte[BLOCK_HEADER_SIZE];
int blockOffset = dbIndex.getRecordHeader(recordId, header);
int dataSize = RecordStoreUtil.getInt(header, 4);
dbFile.seek(blockOffset+BLOCK_HEADER_SIZE);
return dbFile.read(buffer, offset, dataSize);
} catch (java.io.IOException ioe) {
throw new RecordStoreException("error reading record data");
}
}
}
/**
* Returns a copy of the data stored in the given record.
*
* @param recordId the ID of the record to use in this operation
*
* @exception RecordStoreNotOpenException if the record store is
* not open
* @exception InvalidRecordIDException if the recordId is invalid
* @exception RecordStoreException if a general record store
* exception occurs
*
* @return the data stored in the given record. Note that if the
* record has no data, this method will return null.
* @see #setRecord
*/
public byte[] getRecord(int recordId)
throws RecordStoreNotOpenException, InvalidRecordIDException,
RecordStoreException {
synchronized (rsLock) {
try {
byte[] header = new byte[BLOCK_HEADER_SIZE];
int blockOffset = dbIndex.getRecordHeader(recordId, header);
int dataSize = RecordStoreUtil.getInt(header, 4);
if (dataSize == 0) {
return null;
}
byte[] buffer = new byte[dataSize];
dbFile.seek(blockOffset+BLOCK_HEADER_SIZE);
dbFile.read(buffer);
return buffer;
} catch (java.io.IOException ioe) {
throw new RecordStoreException("error reading record data");
}
}
}
/**
* Sets the data in the given record to that passed in. After
* this method returns, a call to <code>getRecord(int recordId)</code>
* will return an array of numBytes size containing the data
* supplied here.
*
* @param recordId the ID of the record to use in this operation
* @param newData the new data to store in the record
* @param offset the index into the data buffer of the first
* relevant byte for this record
* @param numBytes the number of bytes of the data buffer to use
* for this record
*
* @exception RecordStoreNotOpenException if the record store is
* not open
* @exception InvalidRecordIDException if the recordId is invalid
* @exception RecordStoreException if a general record store
* exception occurs
* @exception RecordStoreFullException if the operation cannot be
* completed because the record store has no more room
* @exception SecurityException if the MIDlet has read-only access
* to the RecordStore
* @see #getRecord
*/
public void setRecord(int recordId, byte[] newData,
int offset, int numBytes)
throws RecordStoreNotOpenException, InvalidRecordIDException,
RecordStoreException, RecordStoreFullException {
synchronized (rsLock) {
try {
byte[] header = new byte[BLOCK_HEADER_SIZE];
int blockOffset = dbIndex.getRecordHeader(recordId, header);
int oldBlockSize =
RecordStoreUtil.calculateBlockSize(RecordStoreUtil.getInt(
header, 4));
int newBlockSize = RecordStoreUtil.calculateBlockSize(numBytes);
if (newBlockSize <= oldBlockSize) {
// reuse the old block
splitBlock(blockOffset, header, newData, offset, numBytes);
} else {
// free the old record data
freeBlock(blockOffset, header);
// add a block that contains the new record data
addBlock(recordId, newData, offset, numBytes);
}
// update the db header
RecordStoreUtil.putInt(getVersion()+1, dbHeader, RS4_VERSION);
RecordStoreUtil.putLong(System.currentTimeMillis(), dbHeader,
RS5_LAST_MODIFIED);
// write out the changes to the db header
dbFile.seek(RS4_VERSION);
dbFile.write(dbHeader, RS4_VERSION, 4+8);
// dbFile.commitWrite();
} catch (java.io.IOException ioe) {
throw new RecordStoreException("error setting record data");
}
}
}
/**
* Returns all of the recordId's currently in the record store.
*
* @return an array of the recordId's currently in the record store
* or null if the record store is closed.
*/
public int[] getRecordIDs() {
synchronized (rsLock) {
return dbIndex.getRecordIDs();
}
}
/**
* Returns data base file associated with this record store
*
* @return data base file
*/
public AbstractRecordStoreFile getDbFile() {
return dbFile;
}
/**
* Creates data base index file associated with this record store
*
* @param suiteId unique ID of the suite that owns the store
* @param name a string to name the index file
* @return data base index file
* @exception IOException if failed to create a file
*/
public AbstractRecordStoreFile createIndexFile(int suiteId, String name)
throws IOException {
return new RecordStoreFile(suiteId, name,
AbstractRecordStoreFile.IDX_EXTENSION);
}
/**
* Remove free blocks from the record store and compact records
* with data into as small a space in <code>dbFile</code> as
* possible. Operates from smallest to greatest offset in
* <code>dbFile</code>, copying data in chunks towards the
* beginning of the file, and updating record store meta-data
* as it progresses.
*
* Warning: This is a slow operation that scales linearly
* with dbFile size.
*
* @exception RecordStoreNotOpenException if this record store
* is closed
* @exception RecordStoreException if an error occurs during record
* store compaction
*/
private void compactRecords()
throws IOException {
// check if the db can be compacted
if (RecordStoreUtil.getInt(dbHeader, RS7_FREE_SIZE) == 0) {
// no free space to compact
return;
}
byte[] header = new byte[BLOCK_HEADER_SIZE];
int currentId = 0;
int currentOffset = RecordStoreImpl.DB_HEADER_SIZE;
int currentSize = 0;
int moveUpNumBytes = 0;
// search through the data blocks for a free block that is large enough
while (currentOffset < getSize()) {
// seek to the next offset
dbFile.seek(currentOffset);
// read the block header
if (dbFile.read(header) != RecordStoreImpl.BLOCK_HEADER_SIZE) {
// could not read the block
throw new IOException();
}
currentId = RecordStoreUtil.getInt(header, 0);
currentSize =
RecordStoreUtil.calculateBlockSize(RecordStoreUtil.getInt(
header, 4));
if (Logging.REPORT_LEVEL <= Logging.INFORMATION) {
Logging.report(Logging.INFORMATION, LogChannels.LC_RMS,
"currentId = " + currentId +
" currentSize = " + currentSize);
}
// check if this is a free block or a record
if (currentId < 0) {
if (Logging.REPORT_LEVEL <= Logging.INFORMATION) {
Logging.report(Logging.INFORMATION, LogChannels.LC_RMS,
"found free block at offset " +
currentOffset);
}
// a free block, add to the moveUpNumBytes
moveUpNumBytes += currentSize;
// remove from the index
dbIndex.removeBlock(currentOffset, header);
} else {
if (Logging.REPORT_LEVEL <= Logging.INFORMATION) {
Logging.report(Logging.INFORMATION, LogChannels.LC_RMS,
"found record block at offset " +
currentOffset);
}
// a record data block, check if it needs to be moved up
if (moveUpNumBytes > 0) {
if (Logging.REPORT_LEVEL <= Logging.INFORMATION) {
Logging.report(Logging.INFORMATION, LogChannels.LC_RMS,
"moveUpNumBytes = " + currentOffset);
}
int numMoved = 0;
while (numMoved < currentSize) {
int curRead = currentSize - numMoved;
if (curRead > COMPACT_BUFFER_SIZE) {
curRead = COMPACT_BUFFER_SIZE;
}
dbFile.seek(currentOffset + numMoved);
curRead = dbFile.read(compactBuffer, 0, curRead);
if (curRead == -1) {
throw new IOException();
}
dbFile.seek(currentOffset + numMoved - moveUpNumBytes);
dbFile.write(compactBuffer, 0, curRead);
// dbFile.commitWrite();
numMoved += curRead;
}
dbIndex.updateBlock(currentOffset - moveUpNumBytes, header);
}
}
// added the block size to the currentOffset
currentOffset += currentSize;
}
// check if the db file can be truncated
if (moveUpNumBytes > 0) {
RecordStoreUtil.putInt(
RecordStoreUtil.getInt(dbHeader, RS6_DATA_SIZE) -
moveUpNumBytes, dbHeader, RS6_DATA_SIZE);
RecordStoreUtil.putInt(0, dbHeader, RS7_FREE_SIZE);
dbFile.seek(RS6_DATA_SIZE);
dbFile.write(dbHeader, RS6_DATA_SIZE, 4+4);
// dbFile.commitWrite();
dbFile.truncate(getSize());
if (Logging.REPORT_LEVEL <= Logging.INFORMATION) {
Logging.report(Logging.INFORMATION, LogChannels.LC_RMS,
"compactRecords, truncate to size " +
getSize());
}
}
}
/**
* Set the record in the block to the data passed in and adds any remaining
* space to the free list.
*
* @param blockOffset the offset in db file to the block to split
* @param header the header of the block to split
* @param newData the new data to store in the record
* @param offset the index into the data buffer of the first
* relevant byte for this record
* @param numBytes the number of bytes of the data buffer to use
* for this record
*
* @exception IOException if there is an error accessing the db file
*/
private void splitBlock(int blockOffset, byte[] header,
byte[] newData, int offset,
int numBytes) throws IOException {
if (Logging.REPORT_LEVEL <= Logging.INFORMATION) {
Logging.report(Logging.INFORMATION, LogChannels.LC_RMS,
"splitBlock("+RecordStoreUtil.getInt(header, 0) +
") old numBytes = " + RecordStoreUtil.getInt(header, 4) +
" new numBytes=" + numBytes);
}
// calculate the size of the block
int oldBlockSize =
RecordStoreUtil.calculateBlockSize(RecordStoreUtil.getInt(
header, 4));
// calculate the size of the block
int newBlockSize = RecordStoreUtil.calculateBlockSize(numBytes);
// update the block header
RecordStoreUtil.putInt(numBytes, header, 4);
// seek to the location and write the block and header
writeBlock(blockOffset, header, newData, offset, numBytes);
// check if there is any left over free space
int freeSize = oldBlockSize - newBlockSize - BLOCK_HEADER_SIZE;
if (freeSize >= 0) {
// update the block header and free block of extra space
RecordStoreUtil.putInt(freeSize, header, 4);
freeBlock(blockOffset+newBlockSize, header);
}
}
/**
* Adds a block for the record and data or sets an existing block to
* the data. Splits an exiting block if needed.
*
* @param recordId the ID of the record to use in this operation
* @param data the new data to store in the record
* @param offset the index into the data buffer of the first
* relevant byte for this record
* @param numBytes the number of bytes of the data buffer to use
* for this record
*
* @exception RecordStoreFullException if the operation cannot be
* completed because the record store has no more room
* @exception IOException if there is an error accessing the db file
* @exception RecordStoreException if the new consumption is gong to
* exceed the resource limit
*
* @return the offset in the db file of the block added
*/
private int addBlock(int recordId, byte[] data, int offset, int numBytes)
throws IOException, RecordStoreFullException, RecordStoreException {
if (Logging.REPORT_LEVEL <= Logging.INFORMATION) {
Logging.report(Logging.INFORMATION, LogChannels.LC_RMS,
"addBlock("+recordId+") numBytes="+numBytes);
}
// calculate the size of the block needed
int blockSize = RecordStoreUtil.calculateBlockSize(numBytes);
int blockOffset = 0;
int freeBlocksSize = RecordStoreUtil.getInt(dbHeader, RS7_FREE_SIZE);
// initialize the block header
byte[] header = new byte[BLOCK_HEADER_SIZE];
// check if there is the potential for a large enough free block
if (freeBlocksSize >= blockSize) {
if (Logging.REPORT_LEVEL <= Logging.INFORMATION) {
Logging.report(Logging.INFORMATION, LogChannels.LC_RMS,
"blockSize = " + blockSize +
"free size = " + freeBlocksSize);
}
// initialize the number of bytes and search for an
// available free block
RecordStoreUtil.putInt(numBytes, header, 4);
blockOffset = dbIndex.getFreeBlock(header);
}
// set the recordId in to the block header
RecordStoreUtil.putInt(recordId, header, 0);
if (blockOffset > 0) {
// search found a block, use it
splitBlock(blockOffset, header, data, offset, numBytes);
} else {
// search failed, add a new block to the end of the db file
int spaceAvailable = getSizeAvailable();
/**
* spaceAvailable returns the smaller number of total space
* available and the storage limit per suite. If it is less than
* the block size to be added, RecordStoreFullException is thrown
*/
if (Logging.REPORT_LEVEL <= Logging.INFORMATION) {
Logging.report(Logging.INFORMATION, LogChannels.LC_RMS,
"spaceAvailable = "+spaceAvailable);
}
// Is there room to grow the file?
if (spaceAvailable < blockSize) {
// Is there enough room totally: in storage and free blocks?
if (spaceAvailable + freeBlocksSize < blockSize) {
throw new RecordStoreFullException();
}
compactRecords();
}
blockOffset = getSize();
// seek to the location and write the block and header
RecordStoreUtil.putInt(numBytes, header, 4);
writeBlock(blockOffset, header, data, offset, numBytes);
// update the db data size
RecordStoreUtil.putInt(RecordStoreUtil.getInt(dbHeader, RS6_DATA_SIZE) + blockSize,
dbHeader, RS6_DATA_SIZE);
dbFile.seek(RS6_DATA_SIZE);
dbFile.write(dbHeader, RS6_DATA_SIZE, 4);
// dbFile.commitWrite();
if (Logging.REPORT_LEVEL <= Logging.INFORMATION) {
Logging.report(Logging.INFORMATION, LogChannels.LC_RMS,
"blockOffset = "+blockOffset);
}
}
return blockOffset;
}
/**
* Mark the block at the given offset in db file as free.
*
* @param blockOffset the offset in db file to the block to free
* @param header the header of the block to free
*
* @exception IOException if there is an error accessing the db file
*/
private void freeBlock(int blockOffset, byte[] header) throws IOException {
int dataSize = RecordStoreUtil.getInt(header, 4);
// calculate the size of the block
int blockSize = RecordStoreUtil.calculateBlockSize(dataSize);
if (Logging.REPORT_LEVEL <= Logging.INFORMATION) {
Logging.report(Logging.INFORMATION, LogChannels.LC_RMS,
"freeBlock(" + blockOffset + ") size = " +
blockSize);
}
// mark the block as free
RecordStoreUtil.putInt(-1, header, 0);
RecordStoreUtil.putInt(blockSize - BLOCK_HEADER_SIZE, header, 4);
// save the updated block header
writeBlock(blockOffset, header, null, 0, 0);
// add to the db free size
RecordStoreUtil.putInt(RecordStoreUtil.getInt(dbHeader, RS7_FREE_SIZE) + blockSize,
dbHeader, RS7_FREE_SIZE);
dbFile.seek(RS7_FREE_SIZE);
dbFile.write(dbHeader, RS7_FREE_SIZE, 4);
// dbFile.commitWrite();
}
/**
* Writes a block to the db file at the given offset.
*
* @param blockOffset the offset in db file to write the block
* @param header the header of the block to write
* @param data the new data to store in the record
* @param offset the index into the data buffer of the first
* relevant byte for this record
* @param numBytes the number of bytes of the data buffer to use
* for this record
*
* @exception IOException if there is an error accessing the db file
*/
private void writeBlock(int blockOffset, byte[] header,
byte[] data, int offset, int numBytes)
throws IOException {
int remainder;
dbFile.seek(blockOffset);
dbFile.write(header);
if (data != null && numBytes > 0) {
dbFile.write(data, offset, numBytes);
remainder = numBytes % BLOCK_HEADER_SIZE;
if (remainder != 0) {
// DB_SIGNATURE used here as meaningless pad bytes
dbFile.write(DB_SIGNATURE, 0, BLOCK_HEADER_SIZE - remainder);
}
}
// flush the writes
// dbFile.commitWrite();
// update the index
dbIndex.updateBlock(blockOffset, header);
}
/**
* Creates a RecordStoreImpl instance; for internal use only.
* Callers from outside must use <code>openRecordStore()</code>.
*
* @param suiteId unique ID of the suite that owns the store
* @param recordStoreName a string to name the record store
* @param create if true, create the record store if it doesn't exist
*
* @exception RecordStoreException if something goes wrong setting up
* the new RecordStore.
* @exception RecordStoreNotFoundException if can't find the record store
* and create is set to false.
* @exception RecordStoreFullException if there is no room in storage
* to create a new record store
*/
private RecordStoreImpl(int suiteId, String recordStoreName,
boolean create)
throws RecordStoreException, RecordStoreNotFoundException {
this.suiteId = suiteId;
rsLock = new Object();
boolean exists = RecordStoreUtil.exists(suiteId, recordStoreName,
RecordStoreFile.DB_EXTENSION);
// Check for errors between app and record store existance.
if (!create && !exists) {
throw new RecordStoreNotFoundException("cannot find record "
+ "store file");
}
/*
* If a new RecordStoreImpl will be created in storage,
* check to see if the space required is available.
*/
if (create && !exists) {
int space = RecordStoreFile.spaceAvailableNewRecordStore(suiteId);
if (space - DB_HEADER_SIZE < 0) {
throw new RecordStoreFullException();
}
}
// Create a RecordStoreFile for storing the record store.
try {
dbFile = new RecordStoreFile(suiteId, recordStoreName,
RecordStoreFile.DB_EXTENSION);
// allocate a new header
dbHeader = new byte[DB_HEADER_SIZE];
if (exists) {
// load header
dbFile.read(dbHeader);
/*
* Verify that the file is actually a record store
* by verifying the record store "signature."
*/
for (int i = 0; i < DB_SIGNATURE.length; i++) {
if (dbHeader[i] != DB_SIGNATURE[i]) {
throw new RecordStoreException("invalid record "+
"store contents");
}
}
} else {
// initialize the header
for (int i = 0; i < DB_SIGNATURE.length; i++) {
dbHeader[i] = DB_SIGNATURE[i];
}
RecordStoreUtil.putInt(1, dbHeader, RS2_NEXT_ID);
RecordStoreUtil.putLong(System.currentTimeMillis(), dbHeader,
RS5_LAST_MODIFIED);
// write the header to the file
dbFile.write(dbHeader);
dbFile.commitWrite();
}
// create the index object
dbIndex = new RecordStoreIndex(this, suiteId, recordStoreName);
} catch (java.io.IOException ioe) {
try {
if (dbFile != null) {
dbFile.close();
}
} catch (java.io.IOException ioe2) {
// ignore exception within exception block
}
if (!exists) {
// avoid preserving just created damaged files
RecordStoreUtil.quietDeleteFile(suiteId,
recordStoreName, RecordStoreFile.DB_EXTENSION);
RecordStoreIndex.deleteIndex(suiteId, recordStoreName);
}
dbFile = null;
throw new RecordStoreException("error opening record store " +
"file");
}
}
}
|
