Revise backend libpq interfaces so that messages to the frontend

can be generated in a buffer and then sent to the frontend in a single
libpq call.  This solves problems with NOTICE and ERROR messages generated
in the middle of a data message or COPY OUT operation.

4 files changed, 119 insertions, 92 deletions

diff --git a/src/include/lib/stringinfo.h b/src/include/lib/stringinfo.h
index cf766521ecb..6b86fd6552e 100644
--- a/src/include/lib/stringinfo.h
+++ b/src/include/lib/stringinfo.h
@@ -1,52 +1,108 @@
 /*-------------------------------------------------------------------------
  *
  * stringinfo.h
- *	  Declarations/definitons for "string" functions.
+ *	  Declarations/definitions for "StringInfo" functions.
  *
+ * StringInfo provides an indefinitely-extensible string data type.
+ * It can be used to buffer either ordinary C strings (null-terminated text)
+ * or arbitrary binary data.  All storage is allocated with palloc().
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: stringinfo.h,v 1.10 1999/02/13 23:21:32 momjian Exp $
+ * $Id: stringinfo.h,v 1.11 1999/04/25 03:19:27 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
 #ifndef STRINGINFO_H
 #define STRINGINFO_H
 
-
 /*-------------------------
- * StringInfoData holds information about a string.
- *		'data' is the string.
- *		'len' is the current string length (as returned by 'strlen')
- *		'maxlen' is the size in bytes of 'data', i.e. the maximum string
- *				size (including the terminating '\0' char) that we can
+ * StringInfoData holds information about an extensible string.
+ *		data	is the current buffer for the string (allocated with palloc).
+ *		len		is the current string length.  There is guaranteed to be
+ *				a terminating '\0' at data[len], although this is not very
+ *				useful when the string holds binary data rather than text.
+ *		maxlen	is the allocated size in bytes of 'data', i.e. the maximum
+ *				string size (including the terminating '\0' char) that we can
  *				currently store in 'data' without having to reallocate
- *				more space.
+ *				more space.  We must always have maxlen > len.
+ *-------------------------
  */
 typedef struct StringInfoData
 {
 	char	   *data;
-	int			maxlen;
 	int			len;
+	int			maxlen;
 } StringInfoData;
 
 typedef StringInfoData *StringInfo;
 
+
+/*------------------------
+ * There are two ways to create a StringInfo object initially:
+ *
+ * StringInfo stringptr = makeStringInfo();
+ *		Both the StringInfoData and the data buffer are palloc'd.
+ *
+ * StringInfoData string;
+ * initStringInfo(&string);
+ *		The data buffer is palloc'd but the StringInfoData is just local.
+ *		This is the easiest approach for a StringInfo object that will
+ *		only live as long as the current routine.
+ *
+ * To destroy a StringInfo, pfree() the data buffer, and then pfree() the
+ * StringInfoData if it was palloc'd.  There's no special support for this.
+ *
+ * NOTE: some routines build up a string using StringInfo, and then
+ * release the StringInfoData but return the data string itself to their
+ * caller.  At that point the data string looks like a plain palloc'd
+ * string.
+ *-------------------------
+ */
+
 /*------------------------
  * makeStringInfo
- * create a 'StringInfoData' & return a pointer to it.
+ * Create an empty 'StringInfoData' & return a pointer to it.
  */
 extern StringInfo makeStringInfo(void);
 
 /*------------------------
+ * initStringInfo
+ * Initialize a StringInfoData struct (with previously undefined contents)
+ * to describe an empty string.
+ */
+extern void initStringInfo(StringInfo str);
+
+/*------------------------
  * appendStringInfo
- * similar to 'strcat' but reallocates more space if necessary...
+ * Format text data under the control of fmt (an sprintf-like format string)
+ * and append it to whatever is already in str.  More space is allocated
+ * to str if necessary.  This is sort of like a combination of sprintf and
+ * strcat.
+ * CAUTION: the current implementation has a 1K limit on the amount of text
+ * generated in a single call (not on the total string length).
+ */
+extern void appendStringInfo(StringInfo str, const char *fmt, ...);
+
+/*------------------------
+ * appendStringInfoChar
+ * Append a single byte to str.
+ * Like appendStringInfo(str, "%c", ch) but much faster.
+ */
+extern void appendStringInfoChar(StringInfo str, char ch);
+
+/*------------------------
+ * appendBinaryStringInfo
+ * Append arbitrary binary data to a StringInfo, allocating more space
+ * if necessary.
  */
-extern void appendStringInfo(StringInfo str, const char *fmt,...);
+extern void appendBinaryStringInfo(StringInfo str,
+								   const char *data, int datalen);
 
 /*------------------------
- * nullStringInfo
- * return the string itself or "<>" if it is NULL
+ * stringStringInfo
+ * Return the string itself or "<>" if it is NULL.
+ * This is just a convenience macro used by many callers of appendStringInfo.
  */
 #define stringStringInfo(s) (((s) == NULL) ? "<>" : (s))
 
diff --git a/src/include/libpq/libpq.h b/src/include/libpq/libpq.h
index 99d408d9c15..873992739ee 100644
--- a/src/include/libpq/libpq.h
+++ b/src/include/libpq/libpq.h
@@ -6,7 +6,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: libpq.h,v 1.27 1999/02/13 23:21:35 momjian Exp $
+ * $Id: libpq.h,v 1.28 1999/04/25 03:19:13 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -121,17 +121,6 @@ extern PortalEntry **portals;
 extern size_t portals_array_size;
 
 /*
- *	Asynchronous notification
- */
-typedef struct PQNotifyList
-{
-	char		relname[NAMEDATALEN];	/* listen/notify name */
-	int			be_pid;			/* process id of backend */
-	int			valid;			/* has this already been handled by user. */
-/*	  SLNode Node; */
-} PQNotifyList;
-
-/*
  * Exceptions.
  */
 
@@ -194,11 +183,6 @@ extern char *PQgetvalue(PortalBuffer *portal, int tuple_index, int field_number)
 extern char *PQgetAttr(PortalBuffer *portal, int tuple_index, int field_number);
 extern int	PQgetlength(PortalBuffer *portal, int tuple_index, int field_number);
 extern void PQclear(char *pname);
-extern void PQcleanNotify(void);
-extern void PQnotifies_init(void);
-extern PQNotifyList *PQnotifies(void);
-extern void PQremoveNotify(PQNotifyList *nPtr);
-extern void PQappendNotify(char *relname, int pid);
 
 /*
  * prototypes for functions in portalbuf.c
@@ -250,51 +234,19 @@ extern int32 pqtest(struct varlena * vlena);
 /*
  * prototypes for functions in pqcomm.c
  */
-extern void pq_init(int fd);
-extern void pq_gettty(char *tp);
-extern int	pq_getport(void);
-extern void pq_close(void);
-extern int	pq_flush(void);
-extern int	pq_recvbuf(void);
-extern int	pq_getstr(char *s, int maxlen);
-extern int	PQgetline(char *s, int maxlen);
-extern int	PQputline(char *s);
-extern int	pq_getchar(void);
-extern int	pq_peekchar(void);
-extern int	pq_getnchar(char *s, int off, int maxlen);
-extern int	pq_getint(int b);
-extern int  pq_putchar(unsigned char c);
-extern void pq_putstr(char *s);
-extern void pq_putnchar(char *s, int n);
-extern void pq_putint(int i, int b);
-extern int	pq_getinaddr(struct sockaddr_in * sin, char *host, int port);
-extern int	pq_getinserv(struct sockaddr_in * sin, char *host, char *serv);
-
-#ifdef MULTIBYTE
-extern void pq_putncharlen(char *s, int n);
-
-#endif
-
-extern int pq_connect(char *dbname, char *user, char *args, char *hostName,
-		   char *debugTty, char *execFile, short portName);
-extern int	StreamOpen(char *hostName, short portName, Port *port);
-extern void StreamDoUnlink(void);
 extern int	StreamServerPort(char *hostName, short portName, int *fdP);
 extern int	StreamConnection(int server_fd, Port *port);
 extern void StreamClose(int sock);
-
-/*
- * Internal send/receive buffers in libpq.
- * These probably shouldn't be global at all, but unless we merge
- * pqcomm.c and pqcomprim.c they have to be...
- */
-
-#define PQ_BUFFER_SIZE 8192
-
-extern unsigned char PqSendBuffer[PQ_BUFFER_SIZE];
-extern int PqSendPointer;	/* Next index to store a byte in PqSendBuffer */
-extern unsigned char PqRecvBuffer[PQ_BUFFER_SIZE];
-extern int PqRecvPointer;	/* Next index to read a byte from PqRecvBuffer */
-extern int PqRecvLength;	/* End of data available in PqRecvBuffer */
+extern void pq_init(void);
+extern int	pq_getport(void);
+extern void pq_close(void);
+extern int	pq_getbytes(char *s, size_t len);
+extern int	pq_getstring(char *s, size_t len);
+extern int	pq_peekbyte(void);
+extern int	pq_putbytes(const char *s, size_t len);
+extern int	pq_flush(void);
+extern int	pq_putmessage(char msgtype, const char *s, size_t len);
+extern void	pq_startcopyout(void);
+extern void	pq_endcopyout(bool errorAbort);
 
 #endif	 /* LIBPQ_H */
diff --git a/src/include/libpq/pqcomm.h b/src/include/libpq/pqcomm.h
index 2245b83d625..53542993d87 100644
--- a/src/include/libpq/pqcomm.h
+++ b/src/include/libpq/pqcomm.h
@@ -3,16 +3,20 @@
  * pqcomm.h
  *		Definitions common to frontends and backends.
  *
+ * NOTE: for historical reasons, this does not correspond to pqcomm.c.
+ * pqcomm.c's routines are declared in libpq.h.
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: pqcomm.h,v 1.33 1999/02/13 23:21:36 momjian Exp $
+ * $Id: pqcomm.h,v 1.34 1999/04/25 03:19:13 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
 #ifndef PQCOMM_H
 #define PQCOMM_H
 
+#include "postgres.h"
+
 #include <stdio.h>
 #include <sys/types.h>
 #ifdef WIN32
@@ -23,8 +27,6 @@
 #include <netinet/in.h>
 #endif
 
-#include "postgres.h"
-
 /* Define a generic socket address type. */
 
 typedef union SockAddr
@@ -151,18 +153,4 @@ typedef struct CancelRequestPacket
 	uint32		cancelAuthCode; /* secret key to authorize cancel */
 }			CancelRequestPacket;
 
-
-/* in pqcomprim.c */
-int			pqGetShort(int *);
-int			pqGetLong(int *);
-int			pqGetNBytes(char *, size_t);
-int			pqGetString(char *, size_t);
-int			pqGetByte(void);
-
-int			pqPutShort(int);
-int			pqPutLong(int);
-int			pqPutNBytes(const char *, size_t);
-int			pqPutString(const char *);
-int			pqPutByte(int);
-
 #endif	 /* PQCOMM_H */
diff --git a/src/include/libpq/pqformat.h b/src/include/libpq/pqformat.h
new file mode 100644
index 00000000000..2fe48539a2d
--- /dev/null
+++ b/src/include/libpq/pqformat.h
@@ -0,0 +1,31 @@
+/*-------------------------------------------------------------------------
+ *
+ * pqformat.h
+ *		Definitions for formatting and parsing frontend/backend messages
+ *
+ * Copyright (c) 1994, Regents of the University of California
+ *
+ * $Id: pqformat.h,v 1.1 1999/04/25 03:19:14 tgl Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef PQFORMAT_H
+#define PQFORMAT_H
+
+#include "postgres.h"
+#include "lib/stringinfo.h"
+
+#define pq_beginmessage(buf)  initStringInfo(buf)
+
+extern void	pq_sendbyte(StringInfo buf, int byt);
+extern void	pq_sendbytes(StringInfo buf, const char *data, int datalen);
+extern void	pq_sendtext(StringInfo buf, const char *str, int slen);
+extern void	pq_sendstring(StringInfo buf, const char *str, int slen);
+extern void	pq_sendint(StringInfo buf, int i, int b);
+extern void	pq_endmessage(StringInfo buf);
+
+extern int	pq_getint(int *result, int b);
+extern int	pq_getstr(char *s, int maxlen);
+extern int	pq_getnchar(char *s, int len);
+
+#endif	 /* PQFORMAT_H */