World: r3wp
[!REBOL3 Schemes] Implementors guide
older newer | first last |
Graham 10-Jan-2010 [874] | so with a write port ... the buffer is filled with my write data, it gets sent, and then cleared by the tcp device |
Steeve 10-Jan-2010 [875x4] | no |
write port data, can use any buffer | |
if you use the same buffer (ie port/data) for read and write, you may encounter some problems | |
i will not use the same buffer for read and write | |
Graham 10-Jan-2010 [879] | I'm sure I read that write port uses the port/data as its buffer |
Steeve 10-Jan-2010 [880x3] | no, the write function uses any buffer you want as parameter |
because it's a parameted | |
*parameter | |
Graham 10-Jan-2010 [883x3] | hm... I think we are not talking the same thing http://www.rebol.net/wiki/TCP_Port_Details says that the port/data is used by write |
The details of the port actor for WRITE are: 1. Set port/data to WRITE content (binary string) value. (Mainly to keep it GC safe.) 2. Obtain binary string as specified. The buffer is not copied. This is a low level mechanism. 3. Determine start position from index. 4. Determine length from tail-index or from /part if specified. 5. Set IO-request length and data. Zero the actual field (the length actually transferred). 6. Call the TCP device with the IO-request 7. Check for errors 8. Check for immediate completion. If done, set port/data to NONE. | |
So, this means that the port/data buffer is recreated on each read after a write | |
Steeve 10-Jan-2010 [886] | strange, you may be right |
Graham 10-Jan-2010 [887x2] | sometimes I am known to be right .... |
not often ... | |
Steeve 10-Jan-2010 [889x3] | but it's sayed futher that the buffer is not recreated each time a read occurs |
Check IO-Request connection flag. This is not a socket check, it is a request state flag check. Check the port/data for an existing buffer. If no buffer found, allocate one that is of the default size (32,000). Note: not 32K. Compute buffer space available. If available space is less than half the default size, extend the buffer. Recompute buffer space available. Setup the IO-request data and length fields. Data is the buffer tail position. Length is the buffer space available from above. Clear the actual field. Call the TCP device with READ command. Check result for error. If error, throw it. | |
so i think i got it. | |
Graham 10-Jan-2010 [892x4] | it is saying it is recreated itf it does not exist |
eg. after a tcp write | |
if there is sequential tcp read .. it does not recreate | |
seems a lot of gc must be happening at the tcp port | |
Steeve 10-Jan-2010 [896] | i wonder if the doc is up to date |
Graham 10-Jan-2010 [897x2] | I guess Carl has his reasons on doing it this way instead of having separate buffers for read and write |
Have you fixed my ftp scheme so that it works properly yet? | |
Steeve 10-Jan-2010 [899] | who me ? I never say that |
Graham 10-Jan-2010 [900x2] | LOL ... |
needs a lot of work ... :( | |
Pekr 10-Jan-2010 [902] | read/write buffers are shared? |
Graham 10-Jan-2010 [903x2] | yes |
seems to be according to the docs you linked to | |
Steeve 10-Jan-2010 [905] | i should make a try, i have some doubts |
Pekr 10-Jan-2010 [906] | what is it good for? That way you have to read-out all data from buffer first, before you do "reverse" (read/write) operation, or you mess the data, no? |
Graham 10-Jan-2010 [907x2] | yes, copy all your data first before doing a write |
store it in port/locals somewhere | |
Pekr 10-Jan-2010 [909] | it sounds to me as an unnecessary complication. I don't like it. But maybe Carl tried to create push on programmers, pushing them to do sequency of read/write correctly? |
Graham 10-Jan-2010 [910] | seems like a lot of overhead too ... |
Steeve 10-Jan-2010 [911] | i tested. Alternating read/write causes the buffer cleared each times |
Graham 10-Jan-2010 [912] | so the docs are correct |
Steeve 10-Jan-2010 [913] | But the buffer is cleared only after a write action occured . If you receive several read events the data are added to the buffer (buffer not cleared) |
Graham 10-Jan-2010 [914] | Yep, I think that's what I said above |
Steeve 10-Jan-2010 [915x2] | ok, i just confirmed it with tests |
i encountered the famous stack overflow bug. Never never use a [wait] when you treat an event in the awake handler | |
Graham 10-Jan-2010 [917] | I see in Gabriele's prot-http he has an http-awake handler that creates events which he passes on to another awake handler |
Steeve 10-Jan-2010 [918x2] | yes but it"s fake events passed from tcp port thru the fake http port. Actually, it's just calling the event handler function of the fake port |
it's not asynchronous | |
Andreas 10-Jan-2010 [920x4] | it's a pity that we have to "fake" these events, currently |
I'd love to be able to pass "real" events on, WAKE-UP would already be there, but other stuff seems to be missing | |
i tried sending with WAKE-UP from the tcp port to the scheme port, and the scheme port's AWAKE handler even got called | |
but a WAIT on the scheme port never returns, even though the scheme's AWAKE returns true | |
older newer | first last |