/*
Prepare a data packet for sending downstream. This involves reading file data into a suitably sized packet. Return
the 1 if the packet was sent entirely, return zero if the packet could not be completely sent. Return a negative
error code for write errors. This may split the packet if it exceeds the downstreams maximum packet size.
*/
static int prepPacket(HttpQueue *q, HttpPacket *packet)
{
HttpQueue *nextQ;
ssize size, nbytes;
nextQ = q->nextQ;
if (packet->esize > nextQ->packetSize) {
httpPutBackPacket(q, httpSplitPacket(packet, nextQ->packetSize));
size = nextQ->packetSize;
} else {
size = (ssize) packet->esize;
}
if ((size + nextQ->count) > nextQ->max) {
/*
The downstream queue is full, so disable the queue and service downstream queue.
Will re-enable via a writable event on the connection.
*/
httpSuspendQueue(q);
if (!(nextQ->flags & HTTP_QUEUE_SUSPENDED)) {
httpScheduleQueue(nextQ);
}
return 0;
}
if ((nbytes = readFileData(q, packet, q->ioPos, size)) != size) {
return MPR_ERR_CANT_READ;
}
q->ioPos += nbytes;
return 1;
}
static HttpPacket *selectBytes(HttpQueue *q, HttpPacket *packet)
{
HttpRange *range;
HttpStream *stream;
HttpTx *tx;
MprOff endPacket, length, gap, span;
ssize count;
stream = q->stream;
tx = stream->tx;
if ((range = tx->currentRange) == 0) {
return 0;
}
/*
Process the data packet over multiple ranges ranges until all the data is processed or discarded.
*/
while (range && packet) {
length = httpGetPacketLength(packet);
if (length <= 0) {
return 0;
}
endPacket = tx->rangePos + length;
if (endPacket < range->start) {
/* Packet is before the next range, so discard the entire packet and seek forwards */
tx->rangePos += length;
return 0;
} else if (tx->rangePos < range->start) {
/* Packet starts before range so skip some data, but some packet data is in range */
gap = (range->start - tx->rangePos);
tx->rangePos += gap;
if (gap < length) {
httpAdjustPacketStart(packet, (ssize) gap);
}
if (tx->rangePos >= range->end) {
range = tx->currentRange = range->next;
}
/* Keep going and examine next range */
} else {
/* In range */
assert(range->start <= tx->rangePos && tx->rangePos < range->end);
span = min(length, (range->end - tx->rangePos));
span = max(span, 0);
count = (ssize) min(span, q->nextQ->packetSize);
assert(count > 0);
if (length > count) {
/* Split packet if packet extends past range */
httpPutBackPacket(q, httpSplitPacket(packet, count));
}
if (tx->rangeBoundary) {
httpPutPacketToNext(q, createRangePacket(stream, range));
}
tx->rangePos += count;
if (tx->rangePos >= range->end) {
tx->currentRange = range->next;
}
break;
}
}
return packet;
}
