In the spirit of TODO item

* Add use of 'const' for varibles in source tree
(which is misspelled, btw.)
I went through the front-end libpq code and did so. This affects in
particular the various accessor functions (such as PQdb() and
PQgetvalue()) as well as, by necessity, the internal helpers they use.

I have been really thorough in that regard, perhaps some people will find
it annoying that things like
char * foo = PQgetvalue(res, 0, 0)
will generate a warning. On the other hand it _should_ generate one. This
is no real compatibility break, although a few clients will have to be
fixed to suppress warnings. (Which again would be in the spirit of the
above TODO.)

In addition I replaced some int's by size_t's and removed some warnings
(and generated some new ones -- grmpf!). Also I rewrote PQoidStatus (so it
actually honors the const!) and supplied a new function PQoidValue that
returns a proper Oid type. This is only front-end stuff, none of the
communicaton stuff was touched.


The psql patch also adds some new consts to honor the new libpq situation,
as well as fixes a fatal condition that resulted when using the -V
(--version) option and there is no database listening.


So, to summarize, the psql you should definitely put in (with or without
the libpq). If you think I went too far with the const-mania in libpq, let
me know and I'll make adjustments. If you approve it, I will also update
the docs.

        -Peter

--
Peter Eisentraut                  Sernanders vaeg 10:115

5 files changed, 70 insertions, 66 deletions

diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 29df279262..986ee365a5 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -828,7 +828,7 @@ do_connect(const char *new_dbname, const char *new_user, PsqlSettings *pset)
 	PGconn	   *oldconn = pset->db;
 	const char *dbparam = NULL;
 	const char *userparam = NULL;
-	char	   *pwparam = NULL;
+	const char *pwparam = NULL;
 	char	   *prompted_password = NULL;
 	char	   *prompted_user = NULL;
 	bool		need_pass;
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 58534e2575..5e40779cd1 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -519,8 +519,8 @@ describeTableDetails(const char *name, PsqlSettings *pset)
 	printTableOpt myopt = pset->popt.topt;
 	bool		description = GetVariableBool(pset->vars, "description");
 	int			i;
-	char	   *view_def = NULL;
-	char	   *headers[5];
+	const char	   *view_def = NULL;
+	const char *headers[5];
 	char	  **cells = NULL;
 	char	   *title = NULL;
 	char	  **footers = NULL;
@@ -587,11 +587,10 @@ describeTableDetails(const char *name, PsqlSettings *pset)
 	for (i = 0; i < PQntuples(res); i++)
 	{
 		int4		attypmod = atoi(PQgetvalue(res, i, 3));
-		char	   *attype = PQgetvalue(res, i, 1);
+		const char	   *attype = PQgetvalue(res, i, 1);
 
 		/* Name */
-		cells[i * cols + 0] = PQgetvalue(res, i, 0);	/* don't free this
-														 * afterwards */
+		cells[i * cols + 0] = (char*)PQgetvalue(res, i, 0);	/* don't free this afterwards */
 
 		/* Type */
 		cells[i * cols + 1] = xmalloc(NAMEDATALEN + 16);
@@ -609,7 +608,7 @@ describeTableDetails(const char *name, PsqlSettings *pset)
 
 		/* Info */
 		cells[i * cols + 2] = xmalloc(128 + 128);		/* I'm cutting off the
-														 * default string at 128 */
+									 * 'default' string at 128 */
 		cells[i * cols + 2][0] = '\0';
 		if (strcmp(PQgetvalue(res, i, 4), "t") == 0)
 			strcat(cells[i * cols + 2], "not null");
@@ -633,7 +632,7 @@ describeTableDetails(const char *name, PsqlSettings *pset)
 
 		/* Description */
 		if (description)
-			cells[i * cols + 3] = PQgetvalue(res, i, 7);
+			cells[i * cols + 3] = (char*)PQgetvalue(res, i, 7);
 	}
 
 	/* Make title */
@@ -685,7 +684,7 @@ describeTableDetails(const char *name, PsqlSettings *pset)
 
 
 	myopt.tuples_only = false;
-	printTable(title, headers, cells, footers, "llll", &myopt, pset->queryFout);
+	printTable(title, headers, (const char**)cells, (const char**)footers, "llll", &myopt, pset->queryFout);
 
 	/* clean up */
 	free(title);
diff --git a/src/bin/psql/print.c b/src/bin/psql/print.c
index 5c6525b6f3..90b4f59d61 100644
--- a/src/bin/psql/print.c
+++ b/src/bin/psql/print.c
@@ -28,13 +28,14 @@
 
 
 static void
-print_unaligned_text(const char *title, char **headers, char **cells, char **footers,
+print_unaligned_text(const char *title, const char * const * headers,
+		     const char * const * cells, const char * const * footers,
 					 const char *opt_fieldsep, bool opt_barebones,
 					 FILE *fout)
 {
 	unsigned int col_count = 0;
 	unsigned int i;
-	char	  **ptr;
+	const char * const * ptr;
 
 	if (!opt_fieldsep)
 		opt_fieldsep = "";
@@ -80,14 +81,15 @@ print_unaligned_text(const char *title, char **headers, char **cells, char **foo
 
 
 static void
-print_unaligned_vertical(const char *title, char **headers, char **cells, char **footers,
+print_unaligned_vertical(const char *title, const char * const * headers,
+			 const char * const * cells, const char * const * footers,
 						 const char *opt_fieldsep, bool opt_barebones,
 						 FILE *fout)
 {
 	unsigned int col_count = 0;
 	unsigned int i;
 	unsigned int record = 1;
-	char	  **ptr;
+	const char * const * ptr;
 
 	if (!opt_fieldsep)
 		opt_fieldsep = "";
@@ -167,8 +169,9 @@ _print_horizontal_line(const unsigned int col_count, const unsigned int *widths,
 
 
 static void
-print_aligned_text(const char *title, char **headers, char **cells, char **footers,
-const char *opt_align, bool opt_barebones, unsigned short int opt_border,
+print_aligned_text(const char *title, const char * const * headers,
+		   const char * const * cells, const char * const * footers,
+		   const char *opt_align, bool opt_barebones, unsigned short int opt_border,
 				   FILE *fout)
 {
 	unsigned int col_count = 0;
@@ -176,7 +179,7 @@ const char *opt_align, bool opt_barebones, unsigned short int opt_border,
 				tmp;
 	unsigned int *widths,
 				total_w;
-	char	  **ptr;
+	const char * const * ptr;
 
 	/* count columns */
 	for (ptr = headers; *ptr; ptr++)
@@ -308,13 +311,14 @@ const char *opt_align, bool opt_barebones, unsigned short int opt_border,
 
 
 static void
-print_aligned_vertical(const char *title, char **headers, char **cells, char **footers,
+print_aligned_vertical(const char *title, const char * const * headers,
+		       const char * const * cells, const char * const * footers,
 					   bool opt_barebones, unsigned short int opt_border,
 					   FILE *fout)
 {
 	unsigned int col_count = 0;
 	unsigned int record = 1;
-	char	  **ptr;
+	const char * const *ptr;
 	unsigned int i,
 				tmp,
 				hwidth = 0,
@@ -471,14 +475,15 @@ html_escaped_print(const char *in, FILE *fout)
 
 
 static void
-print_html_text(const char *title, char **headers, char **cells, char **footers,
-const char *opt_align, bool opt_barebones, unsigned short int opt_border,
-				char *opt_table_attr,
+print_html_text(const char *title, const char * const * headers,
+		const char * const * cells, const char * const * footers,
+		const char *opt_align, bool opt_barebones, unsigned short int opt_border,
+		const char *opt_table_attr,
 				FILE *fout)
 {
 	unsigned int col_count = 0;
 	unsigned int i;
-	char	  **ptr;
+	const char * const *ptr;
 
 	fprintf(fout, "<table border=%d", opt_border);
 	if (opt_table_attr)
@@ -544,15 +549,16 @@ const char *opt_align, bool opt_barebones, unsigned short int opt_border,
 
 
 static void
-print_html_vertical(const char *title, char **headers, char **cells, char **footers,
-const char *opt_align, bool opt_barebones, unsigned short int opt_border,
-					char *opt_table_attr,
+print_html_vertical(const char *title, const char * const * headers,
+		    const char * const * cells, const char * const * footers,
+		    const char *opt_align, bool opt_barebones, unsigned short int opt_border,
+		    const char *opt_table_attr,
 					FILE *fout)
 {
 	unsigned int col_count = 0;
 	unsigned int i;
 	unsigned int record = 1;
-	char	  **ptr;
+	const char * const *ptr;
 
 	fprintf(fout, "<table border=%d", opt_border);
 	if (opt_table_attr)
@@ -652,14 +658,15 @@ latex_escaped_print(const char *in, FILE *fout)
 
 
 static void
-print_latex_text(const char *title, char **headers, char **cells, char **footers,
-const char *opt_align, bool opt_barebones, unsigned short int opt_border,
+print_latex_text(const char *title, const char * const * headers,
+		 const char * const * cells, const char * const * footers,
+		 const char *opt_align, bool opt_barebones, unsigned short int opt_border,
 				 FILE *fout)
 {
 	unsigned int col_count = 0;
 	unsigned int i;
 	const char *cp;
-	char	  **ptr;
+	const char * const *ptr;
 
 
 	/* print title */
@@ -747,13 +754,14 @@ const char *opt_align, bool opt_barebones, unsigned short int opt_border,
 
 
 static void
-print_latex_vertical(const char *title, char **headers, char **cells, char **footers,
-const char *opt_align, bool opt_barebones, unsigned short int opt_border,
+print_latex_vertical(const char *title, const char * const * headers,
+		     const char * const * cells, const char * const * footers,
+		     const char *opt_align, bool opt_barebones, unsigned short int opt_border,
 					 FILE *fout)
 {
 	unsigned int col_count = 0;
 	unsigned int i;
-	char	  **ptr;
+	const char * const *ptr;
 	unsigned int record = 1;
 
 	(void) opt_align;			/* currently unused parameter */
@@ -833,11 +841,14 @@ const char *opt_align, bool opt_barebones, unsigned short int opt_border,
 
 
 void
-printTable(const char *title, char **headers, char **cells, char **footers,
+printTable(const char *title,
+	   const char * const * headers,
+	   const char * const * cells,
+	   const char * const * footers,
 		   const char *align,
 		   const printTableOpt * opt, FILE *fout)
 {
-	char	   *default_footer[] = {NULL};
+	const char *default_footer[] = {NULL};
 	unsigned short int border = opt->border;
 	FILE	   *pager = NULL,
 			   *output;
@@ -868,7 +879,7 @@ printTable(const char *title, char **headers, char **cells, char **footers,
 		unsigned int col_count = 0,
 					row_count = 0,
 					lines;
-		char	  **ptr;
+		const char * const *ptr;
 		int			result;
 		struct winsize screen_size;
 
@@ -952,11 +963,11 @@ printTable(const char *title, char **headers, char **cells, char **footers,
 
 
 void
-printQuery(PGresult *result, const printQueryOpt * opt, FILE *fout)
+printQuery(const PGresult *result, const printQueryOpt * opt, FILE *fout)
 {
 	int			nfields;
-	char	  **headers;
-	char	  **cells;
+	const char **headers;
+	const char **cells;
 	char	  **footers;
 	char	   *align;
 	int			i;
@@ -1043,8 +1054,9 @@ printQuery(PGresult *result, const printQueryOpt * opt, FILE *fout)
 
 	/* call table printer */
 
-	printTable(opt->title, headers, cells, footers ? footers : opt->footers, align,
-			   &opt->topt, fout);
+	printTable(opt->title, headers, cells,
+		   footers ? (const char * const *)footers : (const char * const *)(opt->footers),
+		   align, &opt->topt, fout);
 
 	free(headers);
 	free(cells);
diff --git a/src/bin/psql/print.h b/src/bin/psql/print.h
index 64d0271f50..5b1c7671b1 100644
--- a/src/bin/psql/print.h
+++ b/src/bin/psql/print.h
@@ -44,7 +44,8 @@ typedef struct _printTableOpt
  * - align is an 'l' or an 'r' for every column, if the output format needs it.
  *	 (You must specify this long enough. Otherwise anything could happen.)
 */
-void printTable(const char *title, char **headers, char **cells, char **footers,
+void printTable(const char *title, const char * const * headers,
+		const char * const * cells, const char * const * footers,
 		   const char *align,
 		   const printTableOpt * opt, FILE *fout);
 
@@ -66,7 +67,7 @@ typedef struct _printQueryOpt
  * It calls the printTable above with all the things set straight.
  */
 void
-			printQuery(PGresult *result, const printQueryOpt * opt, FILE *fout);
+printQuery(const PGresult *result, const printQueryOpt * opt, FILE *fout);
 
 
 #endif	 /* PRINT_H */
diff --git a/src/bin/psql/startup.c b/src/bin/psql/startup.c
index c94f2526b3..1a1688f081 100644
--- a/src/bin/psql/startup.c
+++ b/src/bin/psql/startup.c
@@ -37,10 +37,10 @@
 
 
 static void
-			process_psqlrc(PsqlSettings *pset);
+process_psqlrc(PsqlSettings *pset);
 
 static void
-			showVersion(PsqlSettings *pset, bool verbose);
+showVersion(PsqlSettings *pset);
 
 
 /* Structures to pass information between the option parsing routine
@@ -68,7 +68,7 @@ struct adhoc_opts
 };
 
 static void
-			parse_options(int argc, char *argv[], PsqlSettings *pset, struct adhoc_opts * options);
+parse_options(int argc, char *argv[], PsqlSettings *pset, struct adhoc_opts * options);
 
 
 
@@ -152,7 +152,7 @@ main(int argc, char **argv)
 	free(username);
 	free(password);
 
-	if (PQstatus(settings.db) == CONNECTION_BAD)
+	if (PQstatus(settings.db) == CONNECTION_BAD && options.action != ACT_SHOW_VER)
 	{
 		fprintf(stderr, "Connection to database '%s' failed.\n%s\n", PQdb(settings.db), PQerrorMessage(settings.db));
 		PQfinish(settings.db);
@@ -169,7 +169,7 @@ main(int argc, char **argv)
 
 	if (options.action == ACT_SHOW_VER)
 	{
-		showVersion(&settings, true);
+		showVersion(&settings);
 		PQfinish(settings.db);
 		exit(EXIT_SUCCESS);
 	}
@@ -177,11 +177,8 @@ main(int argc, char **argv)
 
 	if (!GetVariable(settings.vars, "quiet") && !settings.notty && !options.action)
 	{
-		puts("Welcome to psql, the PostgreSQL interactive terminal.\n");
-
-		//showVersion(&settings, false);
-
-		puts("Type:  \\copyright for distribution terms\n"
+		puts("Welcome to psql, the PostgreSQL interactive terminal.\n\n"
+		     "Type:  \\copyright for distribution terms\n"
 			 "       \\h for help with SQL commands\n"
 			 "       \\? for help on internal slash commands\n"
 			 "       \\g or terminate with semicolon to execute query\n"
@@ -509,28 +506,22 @@ process_psqlrc(PsqlSettings *pset)
  * or a mismatch was detected.
  */
 static void
-showVersion(PsqlSettings *pset, bool verbose)
+showVersion(PsqlSettings *pset)
 {
-	PGresult   *res;
-	char	   *versionstr = NULL;
+	PGresult   *res = NULL;
+	const char *versionstr = NULL;
 	long int	release = 0,
 				version = 0,
 				subversion = 0;
 
 	/* get backend version */
+	if (pset->db && PQstatus(pset->db) == CONNECTION_OK) {
 	res = PSQLexec(pset, "SELECT version()");
 	if (PQresultStatus(res) == PGRES_TUPLES_OK)
 		versionstr = PQgetvalue(res, 0, 0);
-
-	if (!verbose)
-	{
-		if (versionstr)
-			puts(versionstr);
-		PQclear(res);
-		return;
 	}
 
-	if (strncmp(versionstr, "PostgreSQL ", 11) == 0)
+	if (versionstr && strncmp(versionstr, "PostgreSQL ", 11) == 0)
 	{
 		char	   *tmp;
 
@@ -539,9 +530,9 @@ showVersion(PsqlSettings *pset, bool verbose)
 		subversion = strtol(tmp + 1, &tmp, 10);
 	}
 
-	printf("Server: %s\npsql", versionstr ? versionstr : "(could not connected)");
+	printf("Server: %s\npsql", versionstr ? versionstr : "(could not connect)");
 
-	if (strcmp(versionstr, PG_VERSION_STR) != 0)
+	if (!versionstr || strcmp(versionstr, PG_VERSION_STR) != 0)
 		printf(&PG_VERSION_STR[strcspn(PG_VERSION_STR, " ")]);
 	printf(" (" __DATE__ " " __TIME__ ")");
 
@@ -569,10 +560,11 @@ showVersion(PsqlSettings *pset, bool verbose)
 
 	puts("");
 
-	if (release < 6 || (release == 6 && version < 5))
+	if (versionstr && (release < 6 || (release == 6 && version < 5)))
 		puts("\nWarning: The server you are connected to is potentially too old for this client\n"
 			 "version. You should ideally be using clients and servers from the same\n"
 			 "distribution.");
 
+	if (res)
 	PQclear(res);
 }