Infrastructure for upgraded error reporting mechanism. elog.c is

rewritten and the protocol is changed, but most elog calls are still
elog calls.  Also, we need to contemplate mechanisms for controlling
all this functionality --- eg, how much stuff should appear in the
postmaster log?  And what API should libpq expose for it?

1 files changed, 84 insertions, 43 deletions

diff --git a/src/backend/lib/stringinfo.c b/src/backend/lib/stringinfo.c
index 0f758b1bd2d..03251beed90 100644
--- a/src/backend/lib/stringinfo.c
+++ b/src/backend/lib/stringinfo.c
@@ -9,7 +9,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	  $Id: stringinfo.c,v 1.33 2003/04/19 00:02:29 tgl Exp $
+ *	  $Id: stringinfo.c,v 1.34 2003/04/24 21:16:43 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -56,61 +56,102 @@ initStringInfo(StringInfo str)
 /*
  * appendStringInfo
  *
- * Format text data under the control of fmt (an sprintf-like format string)
+ * Format text data under the control of fmt (an sprintf-style 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.
  */
 void
-appendStringInfo(StringInfo str, const char *fmt,...)
+appendStringInfo(StringInfo str, const char *fmt, ...)
+{
+	for (;;)
+	{
+		va_list		args;
+		bool		success;
+
+		/* Try to format the data. */
+		va_start(args, fmt);
+		success = appendStringInfoVA(str, fmt, args);
+		va_end(args);
+
+		if (success)
+			break;
+
+		/* Double the buffer size and try again. */
+		enlargeStringInfo(str, str->maxlen);
+	}
+}
+
+/*
+ * appendStringInfoVA
+ *
+ * Attempt to format text data under the control of fmt (an sprintf-style
+ * format string) and append it to whatever is already in str.  If successful
+ * return true; if not (because there's not enough space), return false
+ * without modifying str.  Typically the caller would enlarge str and retry
+ * on false return --- see appendStringInfo for standard usage pattern.
+ *
+ * XXX This API is ugly, but there seems no alternative given the C spec's
+ * restrictions on what can portably be done with va_list arguments: you have
+ * to redo va_start before you can rescan the argument list, and we can't do
+ * that from here.
+ */
+bool
+appendStringInfoVA(StringInfo str, const char *fmt, va_list args)
 {
-	va_list		args;
 	int			avail,
 				nprinted;
 
 	Assert(str != NULL);
 
-	for (;;)
-	{
-		/*
-		 * Try to format the given string into the available space; but if
-		 * there's hardly any space, don't bother trying, just fall
-		 * through to enlarge the buffer first.
-		 */
-		avail = str->maxlen - str->len - 1;
-		if (avail > 16)
-		{
-			/*
-			 * Assert check here is to catch buggy vsnprintf that overruns
-			 * the specified buffer length.  Solaris 7 in 64-bit mode is
-			 * an example of a platform with such a bug.
-			 */
+	/*
+	 * If there's hardly any space, don't bother trying, just fail to make
+	 * the caller enlarge the buffer first.
+	 */
+	avail = str->maxlen - str->len - 1;
+	if (avail < 16)
+		return false;
+
+	/*
+	 * Assert check here is to catch buggy vsnprintf that overruns
+	 * the specified buffer length.  Solaris 7 in 64-bit mode is
+	 * an example of a platform with such a bug.
+	 */
 #ifdef USE_ASSERT_CHECKING
-			str->data[str->maxlen - 1] = '\0';
+	str->data[str->maxlen - 1] = '\0';
 #endif
 
-			va_start(args, fmt);
-			nprinted = vsnprintf(str->data + str->len, avail,
-								 fmt, args);
-			va_end(args);
-
-			Assert(str->data[str->maxlen - 1] == '\0');
-
-			/*
-			 * Note: some versions of vsnprintf return the number of chars
-			 * actually stored, but at least one returns -1 on failure. Be
-			 * conservative about believing whether the print worked.
-			 */
-			if (nprinted >= 0 && nprinted < avail - 1)
-			{
-				/* Success.  Note nprinted does not include trailing null. */
-				str->len += nprinted;
-				break;
-			}
-		}
-		/* Double the buffer size and try again. */
-		enlargeStringInfo(str, str->maxlen);
+	nprinted = vsnprintf(str->data + str->len, avail, fmt, args);
+
+	Assert(str->data[str->maxlen - 1] == '\0');
+
+	/*
+	 * Note: some versions of vsnprintf return the number of chars
+	 * actually stored, but at least one returns -1 on failure. Be
+	 * conservative about believing whether the print worked.
+	 */
+	if (nprinted >= 0 && nprinted < avail - 1)
+	{
+		/* Success.  Note nprinted does not include trailing null. */
+		str->len += nprinted;
+		return true;
 	}
+
+	/* Restore the trailing null so that str is unmodified. */
+	str->data[str->len] = '\0';
+	return false;
+}
+
+/*
+ * appendStringInfoString
+ *
+ * Append a null-terminated string to str.
+ * Like appendStringInfo(str, "%s", s) but faster.
+ */
+void
+appendStringInfoString(StringInfo str, const char *s)
+{
+	appendBinaryStringInfo(str, s, strlen(s));
 }
 
 /*
@@ -163,8 +204,8 @@ appendBinaryStringInfo(StringInfo str, const char *data, int datalen)
  * Make sure there is enough space for 'needed' more bytes
  * ('needed' does not include the terminating null).
  *
- * External callers need not concern themselves with this, since all
- * stringinfo.c routines do it automatically.  However, if a caller
+ * External callers usually need not concern themselves with this, since
+ * all stringinfo.c routines do it automatically.  However, if a caller
  * knows that a StringInfo will eventually become X bytes large, it
  * can save some palloc overhead by enlarging the buffer before starting
  * to store data in it.