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Another round of protocol changes. Backend-to-frontend messages now all

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have length words.  COPY OUT reimplemented per new protocol: it doesn't
need \. anymore, thank goodness.  COPY BINARY to/from frontend works,
at least as far as the backend is concerned --- libpq's PQgetline API
is not up to snuff, and will have to be replaced with something that is
null-safe.  libpq uses message length words for performance improvement
(no cycles wasted rescanning long messages), but not yet for error
recovery.
This commit is contained in:
Tom Lane
2003-04-22 00:08:07 +00:00
parent ca944bd2d4
commit 5ed27e35f3
22 changed files with 782 additions and 357 deletions
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84
src/interfaces/libpq/fe-misc.c
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@ -23,7 +23,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-misc.c,v 1.89 2003/04/19 00:02:30 tgl Exp $
* $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-misc.c,v 1.90 2003/04/22 00:08:07 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -277,12 +277,12 @@ pqPutInt(int value, size_t bytes, PGconn *conn)
/*
* Make sure conn's output buffer can hold bytes_needed bytes (caller must
* include existing outCount into the value!)
* include already-stored data into the value!)
*
* Returns 0 on success, EOF on error
* Returns 0 on success, EOF if failed to enlarge buffer
*/
static int
checkOutBufferSpace(int bytes_needed, PGconn *conn)
pqCheckOutBufferSpace(int bytes_needed, PGconn *conn)
{
int newsize = conn->outBufSize;
char *newbuf;
@ -335,6 +335,66 @@ checkOutBufferSpace(int bytes_needed, PGconn *conn)
return EOF;
}
/*
* Make sure conn's input buffer can hold bytes_needed bytes (caller must
* include already-stored data into the value!)
*
* Returns 0 on success, EOF if failed to enlarge buffer
*/
int
pqCheckInBufferSpace(int bytes_needed, PGconn *conn)
{
int newsize = conn->inBufSize;
char *newbuf;
if (bytes_needed <= newsize)
return 0;
/*
* If we need to enlarge the buffer, we first try to double it in size;
* if that doesn't work, enlarge in multiples of 8K. This avoids
* thrashing the malloc pool by repeated small enlargements.
*
* Note: tests for newsize > 0 are to catch integer overflow.
*/
do {
newsize *= 2;
} while (bytes_needed > newsize && newsize > 0);
if (bytes_needed <= newsize)
{
newbuf = realloc(conn->inBuffer, newsize);
if (newbuf)
{
/* realloc succeeded */
conn->inBuffer = newbuf;
conn->inBufSize = newsize;
return 0;
}
}
newsize = conn->inBufSize;
do {
newsize += 8192;
} while (bytes_needed > newsize && newsize > 0);
if (bytes_needed <= newsize)
{
newbuf = realloc(conn->inBuffer, newsize);
if (newbuf)
{
/* realloc succeeded */
conn->inBuffer = newbuf;
conn->inBufSize = newsize;
return 0;
}
}
/* realloc failed. Probably out of memory */
printfPQExpBuffer(&conn->errorMessage,
"cannot allocate memory for input buffer\n");
return EOF;
}
/*
* pqPutMsgStart: begin construction of a message to the server
*
@ -364,7 +424,7 @@ pqPutMsgStart(char msg_type, PGconn *conn)
else
lenPos = conn->outCount;
/* make sure there is room for it */
if (checkOutBufferSpace(lenPos + 4, conn))
if (pqCheckOutBufferSpace(lenPos + 4, conn))
return EOF;
/* okay, save the message type byte if any */
if (msg_type)
@ -390,7 +450,7 @@ static int
pqPutMsgBytes(const void *buf, size_t len, PGconn *conn)
{
/* make sure there is room for it */
if (checkOutBufferSpace(conn->outMsgEnd + len, conn))
if (pqCheckOutBufferSpace(conn->outMsgEnd + len, conn))
return EOF;
/* okay, save the data */
memcpy(conn->outBuffer + conn->outMsgEnd, buf, len);
@ -486,13 +546,13 @@ pqReadData(PGconn *conn)
*/
if (conn->inBufSize - conn->inEnd < 8192)
{
int newSize = conn->inBufSize * 2;
char *newBuf = (char *) realloc(conn->inBuffer, newSize);
if (newBuf)
if (pqCheckInBufferSpace(conn->inEnd + 8192, conn))
{
conn->inBuffer = newBuf;
conn->inBufSize = newSize;
/*
* We don't insist that the enlarge worked, but we need some room
*/
if (conn->inBufSize - conn->inEnd < 100)
return -1; /* errorMessage already set */
}
}