/*
* Funambol is a mobile platform developed by Funambol, Inc.
* Copyright (C) 2011 Funambol, Inc.
*
* This program is free software; you can redistribute it and/or modify it under
* the terms of the GNU Affero General Public License version 3 as published by
* the Free Software Foundation with the addition of the following permission
* added to Section 15 as permitted in Section 7(a): FOR ANY PART OF THE COVERED
* WORK IN WHICH THE COPYRIGHT IS OWNED BY FUNAMBOL, FUNAMBOL DISCLAIMS THE
* WARRANTY OF NON INFRINGEMENT OF THIRD PARTY RIGHTS.
*
* 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 for more
* details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program; if not, see http://www.gnu.org/licenses or write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301 USA.
*
* You can contact Funambol, Inc. headquarters at 643 Bair Island Road, Suite
* 305, Redwood City, CA 94063, USA, or at email address info@funambol.com.
*
* The interactive user interfaces in modified source and object code versions
* of this program must display Appropriate Legal Notices, as required under
* Section 5 of the GNU Affero General Public License version 3.
*
* In accordance with Section 7(b) of the GNU Affero General Public License
* version 3, these Appropriate Legal Notices must retain the display of the
* "Powered by Funambol" logo. If the display of the logo is not reasonably
* feasible for technical reasons, the Appropriate Legal Notices must display
* the words "Powered by Funambol".
*/
package com.funambol.storage;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Vector;
import java.io.IOException;
import java.io.OutputStream;
import java.io.InputStream;
import com.funambol.platform.FileAdapter;
import com.funambol.platform.PlatformEnvironment;
import com.funambol.util.StringUtil;
import com.funambol.util.QuickSort;
import com.funambol.util.Log;
/**
* This is an implementation of the key value store that stores items in a file.
* There is no real journaling mechanism, but as long as new items are just
* added we do not rewrite everything on save, but rather append the new items.
* One limitation of this implementation is that both keys and values cannot
* contain these sequences:
*
* 1) line feeds
* 2) SEPARATOR (currently defined as =$^&_~=)
*/
public class FileTable extends Table {
private static final String TAG_LOG = "FileTable";
protected Hashtable store;
protected Hashtable pendingAdditions;
// These are special characters that must be escaped because they are used
// to provide a structure to the table
private static final char LF = (char)10;
private static final char SEPARATOR = ',';
private static final char SPECIAL_CHARS[] = {LF, SEPARATOR};
private boolean updated = false;
private boolean appended = false;
private boolean hiddenFile = false;
private FileAdapter file;
private String directory;
private long nextKey = 0;
private int numRefs = 0;
private Object lock = new Object();
public FileTable(String directory, String tableName, int colsType[], int keyIdx) {
this(directory, tableName, null, colsType, keyIdx, false, false);
}
public FileTable(String directory, String tableName, String colsName[], int colsType[], int keyIdx) {
this(directory, tableName, colsName, colsType, keyIdx, false, false);
}
public FileTable(String directory, String tableName, int colsType[], int keyIdx, boolean autoincrement) {
this(directory, tableName, null, colsType, keyIdx, autoincrement, false);
}
public FileTable(String directory, String tableName, String colsName[], int colsType[], int keyIdx,
boolean autoincrement)
{
this(directory, tableName, colsName, colsType, keyIdx, autoincrement, false);
}
public FileTable(String directory, String tableName, String colsName[], int colsType[], int keyIdx,
boolean autoincrement, boolean hiddenFile)
{
super(tableName, colsName, colsType, keyIdx, autoincrement);
if (autoincrement && colsType[keyIdx] != TYPE_LONG) {
throw new IllegalArgumentException("Autoincrement key must have type long");
}
store = new Hashtable();
pendingAdditions = new Hashtable();
this.directory = directory;
this.hiddenFile = hiddenFile;
}
public void open() throws IOException {
synchronized(lock) {
numRefs++;
if (file != null) {
return;
}
file = new FileAdapter(getName());
if (!file.exists()) {
file.create();
} else {
load();
}
}
}
public void close() throws IOException {
if (file == null) {
return;
}
synchronized(lock) {
--numRefs;
if (numRefs == 0) {
file.close();
file = null;
}
}
}
protected void insertTuple(Tuple tuple) throws IOException {
Object key = tuple.getKey();
synchronized(lock) {
putInternal(key, tuple);
pendingAdditions.put(key, tuple);
appended = true;
if (autoincrement) {
tuple.setField(getKeyIdx(), new Long(nextKey++));
}
}
}
protected void updateTuple(Tuple tuple) throws IOException {
Object key = tuple.getKey();
synchronized(lock) {
putInternal(key, tuple);
pendingAdditions.put(key, tuple);
updated = true;
}
}
public boolean contains(String key) {
return store.get(key) != null;
}
protected void deleteTuple(Object key) throws IOException {
synchronized(lock) {
if (store.remove(key) == null) {
throw new IOException("Cannot delete item, not found " + key);
} else {
updated = true;
}
}
}
public void save() throws IOException {
if (!appended && !updated) {
return;
}
if (file == null) {
throw new IOException("Table must be opened before saving it");
}
synchronized(lock) {
boolean fileExists = false;
OutputStream os = null;
// If there have been only additions, then we can append at the end of
// the file. Otherwise we rewrite completely
try {
fileExists = file.exists();
if (!updated) {
// Open in append mode
os = file.openOutputStream(true);
Enumeration keys = pendingAdditions.keys();
while(keys.hasMoreElements()) {
Object key = keys.nextElement();
Tuple tuple = (Tuple)pendingAdditions.get(key);
String newRow = encodeTuple(tuple);
os.write(newRow.getBytes("UTF-8"));
os.write((int)LF);
}
} else {
// Rewrite all the values
os = file.openOutputStream();
Enumeration keys = store.keys();
while(keys.hasMoreElements()) {
Object key = keys.nextElement();
Tuple tuple = (Tuple)store.get(key);
String newRow = encodeTuple(tuple);
os.write(newRow.getBytes("UTF-8"));
os.write((int)LF);
}
}
} finally {
if (os != null) {
try {
os.close();
} catch (IOException ioe) {
}
}
// Reset all the meta information
pendingAdditions.clear();
appended = false;
updated = false;
}
// Hide the file only the first time it is created
if(hiddenFile && !fileExists) {
hideFile(getName());
}
}
}
private void load() throws IOException {
if (file == null) {
throw new IOException("Table must be opened before saving it");
}
synchronized(lock) {
InputStream is = null;
try {
is = file.openInputStream();
StringBuffer currentLine = new StringBuffer();
for(long i=0, l=file.getSize(); i<l; ++i) {
char b = (char)is.read();
if (b == (char)LF) {
// This is the end of a line
String line = currentLine.toString().trim();
Tuple tuple = decodeTuple(line);
if (autoincrement) {
Long key = (Long)tuple.getKey();
if (key.longValue() >= nextKey) {
nextKey = key.longValue() + 1;
}
}
currentLine = new StringBuffer();
} else {
currentLine.append((char)b);
}
}
} finally {
if (is != null) {
try {
is.close();
} catch (IOException ioe) {}
}
}
}
}
public QueryResult query(QueryFilter filter, int orderBy, boolean ascending) throws IOException {
Vector res = new Vector();
synchronized(lock) {
Enumeration keys = store.keys();
while(keys.hasMoreElements()) {
Object key = keys.nextElement();
Tuple tuple = (Tuple)store.get(key);
if (filter != null) {
if (filter.filterRow(tuple)) {
res.addElement(tuple);
}
} else {
res.addElement(tuple);
}
tuple.setOrderingField(orderBy);
}
}
if (orderBy != -1) {
// Perform a quicksort
QuickSort qs = new QuickSort();
qs.quicksort(res, null, ascending);
}
return new VectorQueryResult(res);
}
protected void resetTable() throws IOException {
if (file == null) {
throw new IOException("Table must be opened before saving it");
}
synchronized(lock) {
boolean fileExists = false;
OutputStream os = null;
try {
fileExists = file.exists();
// This truncate the file
os = file.openOutputStream();
} catch (Exception e) {
throw new IOException(e.toString());
} finally {
if (os != null) {
try {
os.close();
} catch (IOException ioe) {
}
}
}
// Hide the file only the first time it is created
if(hiddenFile && !fileExists) {
hideFile(getName());
}
store = new Hashtable();
}
}
protected void dropTable() throws IOException {
if (file != null) {
throw new IOException("Table must be closed before dropping it");
}
synchronized(lock) {
file = new FileAdapter(getName());
file.delete();
}
}
private String encodeTuple(Tuple tuple) {
StringBuffer res = new StringBuffer();
for(int i=0;i<tuple.getArity();++i) {
String v;
if (getColType(i) == TYPE_STRING) {
v = encodeValue(tuple.getStringField(i));
} else if (getColType(i) == TYPE_LONG) {
v = "" + tuple.getLongField(i);
} else {
throw new IllegalStateException("Unknown field type " + getColType(i));
}
if (i > 0) {
res.append(SEPARATOR);
}
res.append(v);
}
return res.toString();
}
private Tuple decodeTuple(String row) {
Tuple tuple = new Tuple(getColsType(), getKeyIdx());
String fields[] = StringUtil.split(row, "" + SEPARATOR);
if (fields.length != getArity()) {
throw new IllegalStateException("FileTable is not properly formatted");
}
for(int i=0;i<getArity();++i) {
if (getColType(i) == TYPE_STRING) {
String v = decodeValue(fields[i]);
tuple.setField(i, v);
} else if (getColType(i) == TYPE_LONG) {
String v = decodeValue(fields[i]);
tuple.setField(i, Long.parseLong(v));
} else {
throw new IllegalStateException("Unknown field type " + getColType(i));
}
}
return tuple;
}
private String encodeValue(String value) {
// We escape this way: any special char is preceeded by a \
// and the slash is doubled
// This is not very efficient, but this implementation is mostly unused
value = StringUtil.replaceAll(value, "\\","\\\\");
for(int i=0;i<SPECIAL_CHARS.length;++i) {
char c = SPECIAL_CHARS[i];
value = StringUtil.replaceAll(value, ""+c,"\\"+c);
}
return value;
}
private String decodeValue(String value) {
// We escape this way: any special char is preceeded by a \
// and the slash is doubled
// This is not very efficient, but this implementation is mostly unused
for(int i=0;i<SPECIAL_CHARS.length;++i) {
char c = SPECIAL_CHARS[i];
value = StringUtil.replaceAll(value, "\\"+c, ""+c);
}
value = StringUtil.replaceAll(value, "\\\\","\\");
return value;
}
/**
* Set the hidden attribute to true for the given filename. The hidden
* attrobute is set only if the file already exists, since otherwise the
* system would throw a IOException.
*
* @param fileName
*/
private void hideFile(String fileName) {
try {
if(file.exists()) {
boolean hidden = file.setHidden(true);
if(!hidden) {
throw new RuntimeException("Cannot hide file");
}
}
} catch (IOException ex) {
Log.error(TAG_LOG, "Filed to hide file: " + fileName, ex);
}
}
private Object putInternal(Object key, Tuple value) {
return store.put(key, value);
}
public class VectorQueryResult implements QueryResult {
private Vector items;
private int idx = 0;
public VectorQueryResult(Vector items) {
this.items = items;
}
public boolean hasMoreElements() {
return idx < items.size();
}
public Tuple nextElement() {
return (idx < items.size()) ? (Tuple)items.elementAt(idx++) : null;
}
public int getCount() {
return items.size();
}
public void close() {
items = null;
}
}
}