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This patch (against the current CVS sources) adds to libpq the functions

Browse Source 
PQconnectStart
PQconnectPoll
PQresetStart
PQresetPoll
PQsetenvStart
PQsetenvPoll
PQsetenvAbort

and brings into the published interface

PQsetenv.

The first four are asynchronous analogues of PQconnectdb and PQreset -
they allow an application to connect to the DB without blocking on
remote I/O.

The PQsetenv functions perform an environment negotiation with the
server.

Internal to libpq, pqReadReady and pqWriteReady have been made available
across the library (they were previously static functions inside
fe-misc.c).  A lot of internal rearrangement has been necessary to
support these changes.

The API documentation has been updated also.

Caveats:

  o  The Windows code does not default to using non-blocking sockets,
since I have no documentation: Define WIN32_NON_BLOCKING_CONNECTIONS to
do that.

  o  The SSL code still blocks.


Ewan Mellor.
This commit is contained in:
Bruce Momjian
1999-11-30 03:08:19 +00:00
parent d264b53d2f
commit 3ab5b1f1e6
5 changed files with 1528 additions and 313 deletions
Download Patch File Download Diff File Expand all files Collapse all files

77
src/interfaces/libpq/fe-misc.c
View File

@ -24,7 +24,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-misc.c,v 1.32 1999/11/11 00:10:14 momjian Exp $
* $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-misc.c,v 1.33 1999/11/30 03:08:19 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -269,29 +269,69 @@ pqPutInt(int value, size_t bytes, PGconn *conn)
/* --------------------------------------------------------------------- */
/* pqReadReady: is select() saying the file is ready to read?
* Returns -1 on failure, 0 if not ready, 1 if ready.
*/
static int
int
pqReadReady(PGconn *conn)
{
fd_set input_mask;
struct timeval timeout;
if (conn->sock < 0)
return 0;
if (!conn || conn->sock < 0)
return -1;
FD_ZERO(&input_mask);
FD_SET(conn->sock, &input_mask);
timeout.tv_sec = 0;
timeout.tv_usec = 0;
retry:
if (select(conn->sock + 1, &input_mask, (fd_set *) NULL, (fd_set *) NULL,
&timeout) < 0)
{
if (errno == EINTR)
/* Interrupted system call - we'll just try again */
goto retry;
printfPQExpBuffer(&conn->errorMessage,
"pqReadReady() -- select() failed: errno=%d\n%s\n",
errno, strerror(errno));
return 0;
return -1;
}
return FD_ISSET(conn->sock, &input_mask);
return FD_ISSET(conn->sock, &input_mask) ? 1 : 0;
}
/* --------------------------------------------------------------------- */
/* pqWriteReady: is select() saying the file is ready to write?
* Returns -1 on failure, 0 if not ready, 1 if ready.
*/
int
pqWriteReady(PGconn *conn)
{
fd_set input_mask;
struct timeval timeout;
if (!conn || conn->sock < 0)
return -1;
FD_ZERO(&input_mask);
FD_SET(conn->sock, &input_mask);
timeout.tv_sec = 0;
timeout.tv_usec = 0;
retry:
if (select(conn->sock + 1, (fd_set *) NULL, &input_mask, (fd_set *) NULL,
&timeout) < 0)
{
if (errno == EINTR)
/* Interrupted system call - we'll just try again */
goto retry;
printfPQExpBuffer(&conn->errorMessage,
"pqWriteReady() -- select() failed: errno=%d\n%s\n",
errno, strerror(errno));
return -1;
}
return FD_ISSET(conn->sock, &input_mask) ? 1 : 0;
}
/* --------------------------------------------------------------------- */
@ -418,8 +458,17 @@ tryAgain:
* be taken much, since in normal practice we should not be trying to
* read data unless the file selected for reading already.
*/
if (!pqReadReady(conn))
return 0; /* definitely no data available */
switch (pqReadReady(conn))
{
case 0:
/* definitely no data available */
return 0;
case 1:
/* ready for read */
break;
default:
goto definitelyFailed;
}
/*
* Still not sure that it's EOF, because some data could have just
@ -570,6 +619,10 @@ pqFlush(PGconn *conn)
if (len > 0)
{
/* We didn't send it all, wait till we can send more */
/* At first glance this looks as though it should block. I think
* that it will be OK though, as long as the socket is
* non-blocking. */
if (pqWait(FALSE, TRUE, conn))
return EOF;
}
@ -599,9 +652,9 @@ pqWait(int forRead, int forWrite, PGconn *conn)
return EOF;
}
/* loop in case select returns EINTR */
for (;;)
if (forRead || forWrite)
{
retry:
FD_ZERO(&input_mask);
FD_ZERO(&output_mask);
if (forRead)
@ -612,14 +665,12 @@ pqWait(int forRead, int forWrite, PGconn *conn)
(struct timeval *) NULL) < 0)
{
if (errno == EINTR)
continue;
goto retry;
printfPQExpBuffer(&conn->errorMessage,
"pqWait() -- select() failed: errno=%d\n%s\n",
errno, strerror(errno));
return EOF;
}
/* On nonerror return, assume we're done */
break;
}
return 0;