Add use of asprintf()

Add asprintf(), pg_asprintf(), and psprintf() to simplify string
allocation and composition.  Replacement implementations taken from
NetBSD.

Reviewed-by: Álvaro Herrera <alvherre@2ndquadrant.com>
Reviewed-by: Asif Naeem <anaeem.it@gmail.com>

2 files changed, 49 insertions, 28 deletions

diff --git a/src/common/fe_memutils.c b/src/common/fe_memutils.c
index bfe79f8e43..7b96a4b6ba 100644
--- a/src/common/fe_memutils.c
+++ b/src/common/fe_memutils.c
@@ -93,6 +93,25 @@ pg_free(void *ptr)
 		free(ptr);
 }
 
+int
+pg_asprintf(char **ret, const char *format, ...)
+{
+	va_list		ap;
+	int			rc;
+
+	va_start(ap, format);
+	rc = vasprintf(ret, format, ap);
+	va_end(ap);
+
+	if (rc < 0)
+	{
+		fprintf(stderr, _("out of memory\n"));
+		exit(EXIT_FAILURE);
+	}
+
+	return rc;
+}
+
 /*
  * Frontend emulation of backend memory management functions.  Useful for
  * programs that compile backend files.
@@ -126,3 +145,23 @@ repalloc(void *pointer, Size size)
 {
 	return pg_realloc(pointer, size);
 }
+
+char *
+psprintf(const char *format, ...)
+{
+	va_list     ap;
+	int         rc;
+	char	   *ret;
+
+	va_start(ap, format);
+	rc = vasprintf(&ret, format, ap);
+	va_end(ap);
+
+	if (rc < 0)
+	{
+		fprintf(stderr, _("out of memory\n"));
+		exit(EXIT_FAILURE);
+	}
+
+	return ret;
+}
diff --git a/src/common/relpath.c b/src/common/relpath.c
index 52f6b751e3..737003aefe 100644
--- a/src/common/relpath.c
+++ b/src/common/relpath.c
@@ -74,7 +74,6 @@ forkname_chars(const char *str, ForkNumber *fork)
 char *
 relpathbackend(RelFileNode rnode, BackendId backend, ForkNumber forknum)
 {
-	int			pathlen;
 	char	   *path;
 
 	if (rnode.spcNode == GLOBALTABLESPACE_OID)
@@ -82,41 +81,33 @@ relpathbackend(RelFileNode rnode, BackendId backend, ForkNumber forknum)
 		/* Shared system relations live in {datadir}/global */
 		Assert(rnode.dbNode == 0);
 		Assert(backend == InvalidBackendId);
-		pathlen = 7 + OIDCHARS + 1 + FORKNAMECHARS + 1;
-		path = (char *) palloc(pathlen);
 		if (forknum != MAIN_FORKNUM)
-			snprintf(path, pathlen, "global/%u_%s",
+			path = psprintf("global/%u_%s",
 					 rnode.relNode, forkNames[forknum]);
 		else
-			snprintf(path, pathlen, "global/%u", rnode.relNode);
+			path = psprintf("global/%u", rnode.relNode);
 	}
 	else if (rnode.spcNode == DEFAULTTABLESPACE_OID)
 	{
 		/* The default tablespace is {datadir}/base */
 		if (backend == InvalidBackendId)
 		{
-			pathlen = 5 + OIDCHARS + 1 + OIDCHARS + 1 + FORKNAMECHARS + 1;
-			path = (char *) palloc(pathlen);
 			if (forknum != MAIN_FORKNUM)
-				snprintf(path, pathlen, "base/%u/%u_%s",
+				path = psprintf("base/%u/%u_%s",
 						 rnode.dbNode, rnode.relNode,
 						 forkNames[forknum]);
 			else
-				snprintf(path, pathlen, "base/%u/%u",
+				path = psprintf("base/%u/%u",
 						 rnode.dbNode, rnode.relNode);
 		}
 		else
 		{
-			/* OIDCHARS will suffice for an integer, too */
-			pathlen = 5 + OIDCHARS + 2 + OIDCHARS + 1 + OIDCHARS + 1
-				+ FORKNAMECHARS + 1;
-			path = (char *) palloc(pathlen);
 			if (forknum != MAIN_FORKNUM)
-				snprintf(path, pathlen, "base/%u/t%d_%u_%s",
+				path = psprintf("base/%u/t%d_%u_%s",
 						 rnode.dbNode, backend, rnode.relNode,
 						 forkNames[forknum]);
 			else
-				snprintf(path, pathlen, "base/%u/t%d_%u",
+				path = psprintf("base/%u/t%d_%u",
 						 rnode.dbNode, backend, rnode.relNode);
 		}
 	}
@@ -125,34 +116,25 @@ relpathbackend(RelFileNode rnode, BackendId backend, ForkNumber forknum)
 		/* All other tablespaces are accessed via symlinks */
 		if (backend == InvalidBackendId)
 		{
-			pathlen = 9 + 1 + OIDCHARS + 1
-				+ strlen(TABLESPACE_VERSION_DIRECTORY) + 1 + OIDCHARS + 1
-				+ OIDCHARS + 1 + FORKNAMECHARS + 1;
-			path = (char *) palloc(pathlen);
 			if (forknum != MAIN_FORKNUM)
-				snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/%u_%s",
+				path = psprintf("pg_tblspc/%u/%s/%u/%u_%s",
 						 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
 						 rnode.dbNode, rnode.relNode,
 						 forkNames[forknum]);
 			else
-				snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/%u",
+				path = psprintf("pg_tblspc/%u/%s/%u/%u",
 						 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
 						 rnode.dbNode, rnode.relNode);
 		}
 		else
 		{
-			/* OIDCHARS will suffice for an integer, too */
-			pathlen = 9 + 1 + OIDCHARS + 1
-				+ strlen(TABLESPACE_VERSION_DIRECTORY) + 1 + OIDCHARS + 2
-				+ OIDCHARS + 1 + OIDCHARS + 1 + FORKNAMECHARS + 1;
-			path = (char *) palloc(pathlen);
 			if (forknum != MAIN_FORKNUM)
-				snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/t%d_%u_%s",
+				path = psprintf("pg_tblspc/%u/%s/%u/t%d_%u_%s",
 						 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
 						 rnode.dbNode, backend, rnode.relNode,
 						 forkNames[forknum]);
 			else
-				snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/t%d_%u",
+				path = psprintf("pg_tblspc/%u/%s/%u/t%d_%u",
 						 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
 						 rnode.dbNode, backend, rnode.relNode);
 		}