Improve some ancient, crufty code in bootstrap + initdb.

At some point back in the last century, somebody felt that reading
all of pg_type twice was cheaper, or at least easier, than using
repalloc() to resize the Typ[] array dynamically.  That seems like an
entirely wacko proposition, so rewrite the code to do it the other
way.  (To add insult to injury, there were two not-quite-identical
copies of said code.)

initdb.c's readfile() function had the same disease of preferring
to do double the I/O to avoid resizing its output array.  Here,
we can make things easier by using the just-invented pg_get_line()
function to handle reading individual lines without a predetermined
notion of how long they are.

On my machine, it's difficult to detect any net change in the
overall runtime of initdb from these changes; but they should
help on slower buildfarm machines (especially since a buildfarm
cycle involves a lot of initdb's these days).

My attention was drawn to these places by scan-build complaints,
but on inspection they needed a lot more work than just suppressing
dead stores :-(

1 files changed, 14 insertions, 32 deletions

diff --git a/src/bin/initdb/initdb.c b/src/bin/initdb/initdb.c
index 73ddf408654..861b8817b93 100644
--- a/src/bin/initdb/initdb.c
+++ b/src/bin/initdb/initdb.c
@@ -468,14 +468,11 @@ filter_lines_with_token(char **lines, const char *token)
 static char **
 readfile(const char *path)
 {
+	char	  **result;
 	FILE	   *infile;
-	int			maxlength = 1,
-				linelen = 0;
-	int			nlines = 0;
+	int			maxlines;
 	int			n;
-	char	  **result;
-	char	   *buffer;
-	int			c;
+	char	   *ln;
 
 	if ((infile = fopen(path, "r")) == NULL)
 	{
@@ -483,39 +480,24 @@ readfile(const char *path)
 		exit(1);
 	}
 
-	/* pass over the file twice - the first time to size the result */
+	maxlines = 1024;
+	result = (char **) pg_malloc(maxlines * sizeof(char *));
 
-	while ((c = fgetc(infile)) != EOF)
+	n = 0;
+	while ((ln = pg_get_line(infile)) != NULL)
 	{
-		linelen++;
-		if (c == '\n')
+		/* make sure there will be room for a trailing NULL pointer */
+		if (n >= maxlines - 1)
 		{
-			nlines++;
-			if (linelen > maxlength)
-				maxlength = linelen;
-			linelen = 0;
+			maxlines *= 2;
+			result = (char **) pg_realloc(result, maxlines * sizeof(char *));
 		}
-	}
-
-	/* handle last line without a terminating newline (yuck) */
-	if (linelen)
-		nlines++;
-	if (linelen > maxlength)
-		maxlength = linelen;
 
-	/* set up the result and the line buffer */
-	result = (char **) pg_malloc((nlines + 1) * sizeof(char *));
-	buffer = (char *) pg_malloc(maxlength + 1);
-
-	/* now reprocess the file and store the lines */
-	rewind(infile);
-	n = 0;
-	while (fgets(buffer, maxlength + 1, infile) != NULL && n < nlines)
-		result[n++] = pg_strdup(buffer);
+		result[n++] = ln;
+	}
+	result[n] = NULL;
 
 	fclose(infile);
-	free(buffer);
-	result[n] = NULL;
 
 	return result;
 }