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/* Copyright (C) 2000-2004 Thomas Bopp, Thorsten Hampel, Ludger Merkens
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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* $Id: db_file.pike,v 1.1.1.1 2006/03/27 12:40:10 exodusd Exp $
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constant cvs_version="$Id: db_file.pike,v 1.1.1.1 2006/03/27 12:40:10 exodusd Exp $";
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* this is the database file emulation, which stores a binary file
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* in a sequence of 64k blobs in a SQL database.
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private static int iNextRecNbr; /* last current read */
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private static int iCurrPos; /* current position */
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private static int iMaxRecNbr; /* last rec_order block */
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private static int iMinRecNbr; /* first rec_order block */
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private static string sMode; /* read/write */
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private static string sReadBuf="";
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private static string sWriteBuf="";
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private static int iFileSize=-1; /* not set otherwise >=0 */
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private static object readRecord;
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private static int iStopReader=0;
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private static Thread.MutexKey mReader;
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private static int iPrefetch=1;
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private static int iLastAccess;
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array get_database_handle(int id)
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return _Database->connect_db_file(id);
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void create(int ID, string mode) {
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* open a database content with given ID, if ID 0 is given a new ID
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* @param int ID - (an Content ID | 0)
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* @param string mode -
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* 'r' open file for reading
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* 'w' open file for writing
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* 'a' open file for append (use with 'w')
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* 't' truncate file at open (use with 'w')
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* 'c' create file if it doesn't exist (use with 'w')
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* 'x' fail if file already exist (use with 'c')
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* How must _always_ contain exactly one 'r' or 'w'.
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* if no ID is given, mode 'wc' is assumed
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* 'w' assumes 'a' unless 't'
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* @return On success the ID (>1) -- 0 otherwise
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* @author Ludger Merkens
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int open(int ID, string mode) {
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Sql.sql_result odbResult; // db = iID >> OID_BITS;
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[fdb, iID] = get_database_handle(iID);
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// LOG("opened db_file for mode "+sMode+" with id "+iID);
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if (search(sMode, "r")!=-1)
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fdb()->big_query("select min(rec_order), max(rec_order) "+
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"from doc_data where "+
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array res= odbResult->fetch_row();
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iMinRecNbr= (int) res[0];
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iMaxRecNbr= (int) res[1]; // both 0 if FileNotFound
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iNextRecNbr = iMinRecNbr;
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fdb()->big_query("select rec_data from doc_data where doc_id="+iID+
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" and rec_order="+iMinRecNbr);
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if (odbResult->num_rows()==1)
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[sReadBuf] = odbResult->fetch_row();
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if (strlen(sReadBuf)<MAX_BUFLEN) // we got the complete file
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iFileSize = strlen(sReadBuf);
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iPrefetch = 1; // otherwise assume prefetching
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if (search(sMode, "w")==-1) // neither read nor write mode given
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// Append to database, calculate next RecNbr
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odbResult = fdb()->big_query("select max(rec_order) from "+
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"doc_data where doc_id = "+iID);
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if (!objectp(odbResult))
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iNextRecNbr = ((int) odbResult->fetch_row()[0])+1;
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if (search(sMode, "c")!=-1)
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if ((search(sMode,"x")!=-1) && (iNextRecNbr != -1))
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if (iNextRecNbr == -1)
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if (search(sMode, "t")!=-1)
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fdb()->big_query("delete from doc_data where doc_id = "+
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if (iNextRecNbr == -1) // 'w' without 'c' but file doesn't exist
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private static void write_buf(string data) {
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// LOG_DB("write_buf: "+strlen(data)+" RecNbr:"+iNextRecNbr);
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string line = "insert into doc_data values('"+
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fdb()->quote(data)+"', "+ iID +", "+iNextRecNbr+")";
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mixed c = catch{fdb()->big_query(line);};
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LOG_DB("write_buf: "+c[0]+"\n"+master()->describe_backtrace(c[1]));
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iMaxRecNbr=iNextRecNbr;
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// werror("closing db_file"+iID+" from mode "+sMode);
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if (search(sMode,"w")!=-1)
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if (strlen(sWriteBuf) > 0)
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write_buf(sWriteBuf);
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iFileSize = (((iMaxRecNbr - iMinRecNbr)-1) * MAX_BUFLEN) +
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static int sendByte = 0;
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int get_last_access() { return iLastAccess; }
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static void check_status(object record)
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mlock = record->fullMutex->lock();
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if ( functionp(record->restore) ) {
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record->restore(record);
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string read(int|void nbytes, int|void notall)
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array(string) lbuf = ({});
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Sql.sql_result odbData;
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if ( search(sMode,"r") == -1 )
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iLastAccess = time();
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if (!nbytes) // all the stuff -> no queuing
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odbData = fdb()->big_query("select rec_data from doc_data "+
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" order by rec_order");
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while (line = odbData->fetch_row())
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lbuf += ({ line[0] });
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else if ( !objectp(readRecord) &&
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(iFileSize == -1 || iFileSize> MAX_BUFLEN ) && iPrefetch )
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readRecord = _Database->read_from_database(iID,
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iSumLen = strlen(sReadBuf);
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lbuf = ({ sReadBuf });
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while ( iSumLen < nbytes && stringp(line) )
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if ( readRecord ) // check for Prefetched Content
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check_status(readRecord);
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line = readRecord->contFifo->read();
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else if (iNextRecNbr < iMaxRecNbr) // large files + seek
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readRecord = _Database->read_from_database(iID,
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check_status(readRecord);
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line = readRecord->contFifo->read();
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line = 0; // small files
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iSumLen += strlen(line);
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sReadBuf = lbuf * "";
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if (!strlen(sReadBuf))
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if (strlen(sReadBuf) <= nbytes) // eof or notall
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iCurrPos += strlen(line);
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sendByte += strlen(line);
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line = sReadBuf[..nbytes-1];
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sReadBuf = sReadBuf[nbytes..];
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iCurrPos += strlen(line);
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sendByte += strlen(line);
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int write(string data) {
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if (search(sMode, "w")==-1)
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while (strlen(sWriteBuf) >= MAX_BUFLEN)
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write_buf(sWriteBuf[..MAX_BUFLEN-1]);
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sWriteBuf = sWriteBuf[MAX_BUFLEN..];
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iWritten += MAX_BUFLEN;
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iCurrPos += iWritten;
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object s = Stdio.Stat();
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if (iFileSize!=-1) // already calculated
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if (search(sMode, "w")!=-1)
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iLastChunkLen = strlen(sWriteBuf);
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erg = ((iMaxRecNbr-iMinRecNbr) * MAX_BUFLEN) + iLastChunkLen;
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res = fdb()->big_query(
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"select length(rec_data) from doc_data "+
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"where doc_id ="+iID+" and rec_order="+iMaxRecNbr);
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mixed row = res->fetch_row();
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iLastChunkLen = ((int)row[0]);
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iFileSize = ((iMaxRecNbr-iMinRecNbr) * MAX_BUFLEN) + iLastChunkLen;
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private static void stop_reader()
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if ( objectp(readRecord) ) {
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//werror("Trying to stop read operation on "+ readRecord->iID+"\n");
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readRecord->stopRead = 1;
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* seek in an already open database content to a specific offset
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* If pos is negative it will be relative to the start of the file,
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* otherwise it will be an absolute offset from the start of the file.
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* @param int pos - the position as described above
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* @return The absolute new offset or -1 on failure
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* @caveats The old syntax from Stdio.File->seek with blocks is not
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Sql.sql_result odbResult;
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//werror("Seek(%d)\n", pos);
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SeekPos = iCurrPos-SeekPos;
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SeekBlock = SeekPos / MAX_BUFLEN;
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SeekBlock += iMinRecNbr;
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stop_reader(); // discard prefetch and stop read_thread
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odbResult = fdb()->big_query("select rec_data from doc_data where doc_id="+
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iID+" and rec_order="+SeekBlock);
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if (odbResult->num_rows()==1)
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[sReadBuf] = odbResult->fetch_row();
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sReadBuf = sReadBuf[(SeekPos % iMinRecNbr)..];
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iNextRecNbr = SeekBlock+1;
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* tell the current offset in an already open database content
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* @return The absolute offset
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return "kernel/db_file(id="+iID+", stopped="+iStopReader+")";
added
removed
server/kernel/db_file.pike
