Synchronet now requires the libarchive development package (e.g. libarchive-dev on Debian-based Linux distros, libarchive.org for more info) to build successfully.

Commit 5e76b051 authored by deuce's avatar deuce

More concurrency changes...

1) Don't mswait(1) on a successful lock, or when timeout is zero.
2) Flush read buffer on Get and ReLoad()
   - If there's a single record in the file, close and re-open it.
   - If a lock is held on a different record already, read that record.
   - Otherwise, read the first record a lock with timeout zero succeeds.
3) Flush write buffer on Put().

This should now actually be safe as long as locks work.
Using file_mutex() on records is the only potential change still needed.
(Because POSIX fcntl() locks are insane)
parent c30e8bb6
......@@ -37,8 +37,7 @@ function RecordFile(filename, definition)
this.file=new File(filename);
this.fields=definition;
this.RecordLength=GetRecordLength(this.fields);
// Hopefully a vbuf of record length prevents stale data?
// It likely doesn't though.
// A vbuf of a record length prevents more than one record from being in the buffer.
if(!this.file.open(file_exists(this.file.name)?"rb+":"wb+",true,this.RecordLength))
return(null);
this.__defineGetter__("length", function() {return parseInt(this.file.length/this.RecordLength);});
......@@ -51,6 +50,71 @@ function RecordFileRecord(parent, num)
this.Record=num;
}
RecordFileRecord.prototype.FlushRead = function(keeplocked)
{
var i;
var locked;
var flushed = false;
locked = (this.parent.locks.indexOf(this.Record) != -1);
if (keeplocked === undefined) {
if (locked)
keeplocked = true;
else
keeplocked = false;
}
// If there's only one record, the only way to flush the buffer is
// to close and re-open...
if (this.parent.length == 1) {
// Which means we need to give up the lock...
if (locked)
this.UnLock();
this.parent.file.close();
if (!this.parent.file.open('rb+', true, this.parent.RecordLength))
throw('Unable to re-open '+this.parent.file.name);
if (locked)
this.Lock();
flushed = true;
}
// Try to force a read cache flush by reading a different record...
// First, try a record we already have locked...
if (!flushed) {
for (i = 0; i < this.parent.locks.length; i++) {
if (i == this.Record)
continue;
this.parent.Get(i, true);
flushed = true;
break;
}
}
// If that failed, try the first one we can get an immediate lock on. :(
if (!flushed) {
for (i = 0; i < this.parent.length; i++) {
if (i == this.Record)
continue;
if (this.parent.locks.indexOf(i) > -1)
continue;
if (this.parent.Lock(i, 0)) {
this.parent.Get(i, false);
break;
}
}
}
if (keeplocked) {
if (locked)
return;
this.Lock();
}
else {
if (locked)
this.UnLock();
}
};
RecordFileRecord.prototype.ReLoad = function(keeplocked)
{
var i;
......@@ -64,7 +128,9 @@ RecordFileRecord.prototype.ReLoad = function(keeplocked)
keeplocked = true;
}
// Locks don't work because threads hate them. :(
this.FlushRead(lock);
// Locks don't work because threads hate them. :(
this.parent.file.position=(this.Record)*this.parent.RecordLength;
if (lock)
while(!this.Lock()); // Forever
......@@ -93,8 +159,8 @@ RecordFile.prototype.Lock = function(rec, timeout)
end.setTime(end.getTime() + timeout*1000);
do {
ret = this.file.lock(rec*this.RecordLength, this.RecordLength);
mswait(1);
if ((ret = this.file.lock(rec*this.RecordLength, this.RecordLength) != true && timeout > 0))
mswait(1);
} while (ret === false && new Date() < end);
if (ret)
......@@ -151,6 +217,7 @@ RecordFileRecord.prototype.Put = function(keeplocked)
for(i=0; i<this.parent.fields.length; i++)
this.parent.WriteField(this[this.parent.fields[i].prop], this.parent.fields[i].type, eval(this.parent.fields[i].def.toSource()).valueOf());
this.parent.file.flush();
if (!keeplocked)
this.UnLock();
......@@ -186,6 +253,8 @@ RecordFile.prototype.Get = function(num, keeplocked)
keeplocked = true;
}
this.FlushRead(lock);
var ret = new RecordFileRecord(this, num);
this.file.position=ret.Record * this.RecordLength;
......
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