Add psql expanded auto mode

This adds the "auto" option to the \x command, which switches to the
expanded mode when the normal output would be wider than the screen.

reviewed by Noah Misch

4 files changed, 54 insertions, 24 deletions

diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 5970ab32c15..9cc73beabff 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -1355,7 +1355,7 @@ exec_command(const char *cmd,
 		free(fname);
 	}
 
-	/* \x -- toggle expanded table representation */
+	/* \x -- set or toggle expanded table representation */
 	else if (strcmp(cmd, "x") == 0)
 	{
 		char	   *opt = psql_scan_slash_option(scan_state,
@@ -2189,14 +2189,21 @@ do_pset(const char *param, const char *value, printQueryOpt *popt, bool quiet)
 	/* set expanded/vertical mode */
 	else if (strcmp(param, "x") == 0 || strcmp(param, "expanded") == 0 || strcmp(param, "vertical") == 0)
 	{
-		if (value)
+		if (value && pg_strcasecmp(value, "auto") == 0)
+			popt->topt.expanded = 2;
+		else if (value)
 			popt->topt.expanded = ParseVariableBool(value);
 		else
 			popt->topt.expanded = !popt->topt.expanded;
 		if (!quiet)
-			printf(popt->topt.expanded
-				   ? _("Expanded display is on.\n")
-				   : _("Expanded display is off.\n"));
+		{
+			if (popt->topt.expanded == 1)
+				printf(_("Expanded display is on.\n"));
+			else if (popt->topt.expanded == 2)
+				printf(_("Expanded display is used automatically.\n"));
+			else
+				printf(_("Expanded display is off.\n"));
+		}
 	}
 
 	/* locale-aware numeric output */
@@ -2356,7 +2363,7 @@ do_pset(const char *param, const char *value, printQueryOpt *popt, bool quiet)
 			popt->topt.columns = atoi(value);
 
 		if (!quiet)
-			printf(_("Target width for \"wrapped\" format is %d.\n"), popt->topt.columns);
+			printf(_("Target width is %d.\n"), popt->topt.columns);
 	}
 
 	else
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index 53e4cd0c0e2..4649e944755 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -242,8 +242,8 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\t [on|off]            show only rows (currently %s)\n"),
 			ON(pset.popt.topt.tuples_only));
 	fprintf(output, _("  \\T [STRING]            set HTML <table> tag attributes, or unset if none\n"));
-	fprintf(output, _("  \\x [on|off]            toggle expanded output (currently %s)\n"),
-			ON(pset.popt.topt.expanded));
+	fprintf(output, _("  \\x [on|off|auto]       toggle expanded output (currently %s)\n"),
+			pset.popt.topt.expanded == 2 ? "auto" : ON(pset.popt.topt.expanded));
 	fprintf(output, "\n");
 
 	fprintf(output, _("Connection\n"));
diff --git a/src/bin/psql/print.c b/src/bin/psql/print.c
index 0d18665566f..b19159d543b 100644
--- a/src/bin/psql/print.c
+++ b/src/bin/psql/print.c
@@ -122,9 +122,11 @@ const printTextFormat pg_utf8format =
 
 /* Local functions */
 static int	strlen_max_width(unsigned char *str, int *target_width, int encoding);
-static void IsPagerNeeded(const printTableContent *cont, const int extra_lines,
+static void IsPagerNeeded(const printTableContent *cont, const int extra_lines, bool expanded,
 			  FILE **fout, bool *is_pager);
 
+static void print_aligned_vertical(const printTableContent *cont, FILE *fout);
+
 
 static void *
 pg_local_malloc(size_t size)
@@ -713,6 +715,17 @@ print_aligned_text(const printTableContent *cont, FILE *fout)
 		}
 	}
 
+	/*
+	 * If in expanded auto mode, we have now calculated the expected width, so
+	 * we can now escape to vertical mode if necessary.
+	 */
+	if (cont->opt->expanded == 2 && output_columns > 0 &&
+		(output_columns < total_header_width || output_columns < width_total))
+	{
+		print_aligned_vertical(cont, fout);
+		return;
+	}
+
 	/* If we wrapped beyond the display width, use the pager */
 	if (!is_pager && fout == stdout && output_columns > 0 &&
 		(output_columns < total_header_width || output_columns < width_total))
@@ -756,7 +769,7 @@ print_aligned_text(const printTableContent *cont, FILE *fout)
 				extra_row_output_lines = 0;
 			}
 		}
-		IsPagerNeeded(cont, extra_output_lines, &fout, &is_pager);
+		IsPagerNeeded(cont, extra_output_lines, false, &fout, &is_pager);
 	}
 
 	/* time to output */
@@ -1125,6 +1138,7 @@ print_aligned_vertical(const printTableContent *cont, FILE *fout)
 				dformatsize = 0;
 	struct lineptr *hlineptr,
 			   *dlineptr;
+	bool		is_pager = false;
 
 	if (cancel_pressed)
 		return;
@@ -1139,6 +1153,13 @@ print_aligned_vertical(const printTableContent *cont, FILE *fout)
 		return;
 	}
 
+	/*
+	 * Deal with the pager here instead of in printTable(), because we could
+	 * get here via print_aligned_text() in expanded auto mode, and so we have
+	 * to recalcuate the pager requirement based on vertical output.
+	 */
+	IsPagerNeeded(cont, 0, true, &fout, &is_pager);
+
 	/* Find the maximum dimensions for the headers */
 	for (i = 0; i < cont->ncolumns; i++)
 	{
@@ -1295,6 +1316,9 @@ print_aligned_vertical(const printTableContent *cont, FILE *fout)
 	free(dlineptr->ptr);
 	free(hlineptr);
 	free(dlineptr);
+
+	if (is_pager)
+		ClosePager(fout);
 }
 
 
@@ -2265,14 +2289,14 @@ printTableCleanup(printTableContent *const content)
  * Setup pager if required
  */
 static void
-IsPagerNeeded(const printTableContent *cont, const int extra_lines, FILE **fout,
+IsPagerNeeded(const printTableContent *cont, const int extra_lines, bool expanded, FILE **fout,
 			  bool *is_pager)
 {
 	if (*fout == stdout)
 	{
 		int			lines;
 
-		if (cont->opt->expanded)
+		if (expanded)
 			lines = (cont->ncolumns + 1) * cont->nrows;
 		else
 			lines = cont->nrows + 1;
@@ -2310,11 +2334,10 @@ printTable(const printTableContent *cont, FILE *fout, FILE *flog)
 	if (cont->opt->format == PRINT_NOTHING)
 		return;
 
-	/* print_aligned_text() handles the pager itself */
-	if ((cont->opt->format != PRINT_ALIGNED &&
-		 cont->opt->format != PRINT_WRAPPED) ||
-		cont->opt->expanded)
-		IsPagerNeeded(cont, 0, &fout, &is_pager);
+	/* print_aligned_*() handles the pager themselves */
+	if (cont->opt->format != PRINT_ALIGNED &&
+		cont->opt->format != PRINT_WRAPPED)
+		IsPagerNeeded(cont, 0, (cont->opt->expanded == 1), &fout, &is_pager);
 
 	/* print the stuff */
 
@@ -2324,32 +2347,32 @@ printTable(const printTableContent *cont, FILE *fout, FILE *flog)
 	switch (cont->opt->format)
 	{
 		case PRINT_UNALIGNED:
-			if (cont->opt->expanded)
+			if (cont->opt->expanded == 1)
 				print_unaligned_vertical(cont, fout);
 			else
 				print_unaligned_text(cont, fout);
 			break;
 		case PRINT_ALIGNED:
 		case PRINT_WRAPPED:
-			if (cont->opt->expanded)
+			if (cont->opt->expanded == 1)
 				print_aligned_vertical(cont, fout);
 			else
 				print_aligned_text(cont, fout);
 			break;
 		case PRINT_HTML:
-			if (cont->opt->expanded)
+			if (cont->opt->expanded == 1)
 				print_html_vertical(cont, fout);
 			else
 				print_html_text(cont, fout);
 			break;
 		case PRINT_LATEX:
-			if (cont->opt->expanded)
+			if (cont->opt->expanded == 1)
 				print_latex_vertical(cont, fout);
 			else
 				print_latex_text(cont, fout);
 			break;
 		case PRINT_TROFF_MS:
-			if (cont->opt->expanded)
+			if (cont->opt->expanded == 1)
 				print_troff_ms_vertical(cont, fout);
 			else
 				print_troff_ms_text(cont, fout);
diff --git a/src/bin/psql/print.h b/src/bin/psql/print.h
index 35bb4cde1d9..bb206136294 100644
--- a/src/bin/psql/print.h
+++ b/src/bin/psql/print.h
@@ -70,8 +70,8 @@ typedef struct printTextFormat
 typedef struct printTableOpt
 {
 	enum printFormat format;	/* see enum above */
-	bool		expanded;		/* expanded/vertical output (if supported by
-								 * output format) */
+	unsigned short int expanded;/* expanded/vertical output (if supported by
+								 * output format); 0=no, 1=yes, 2=auto */
 	unsigned short int border;	/* Print a border around the table. 0=none,
 								 * 1=dividing lines, 2=full */
 	unsigned short int pager;	/* use pager for output (if to stdout and