psql_column_filter.diff

diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 438a4ec..5dad70b 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -1148,7 +1148,8 @@ exec_command(const char *cmd,
 
 			int			i;
 			static const char *const my_list[] = {
-				"border", "columns", "expanded", "fieldsep", "fieldsep_zero",
+				"border", "columns", "column_filter",
+				"expanded", "fieldsep", "fieldsep_zero",
 				"footer", "format", "linestyle", "null",
 				"numericlocale", "pager", "pager_min_lines",
 				"recordsep", "recordsep_zero",
@@ -2695,6 +2696,17 @@ do_pset(const char *param, const char *value, printQueryOpt *popt, bool quiet)
 		if (value)
 			popt->topt.columns = atoi(value);
 	}
+	/* set column filter */
+	else if (strcmp(param, "columnfilter") == 0)
+	{
+		if (vallen > 0)
+			popt->topt.columnfilter = pg_strdup(value);
+		else
+		{
+			if (popt->topt.columnfilter) pg_free(popt->topt.columnfilter);
+			popt->topt.columnfilter = NULL;
+		}
+	}
 	else
 	{
 		psql_error("\\pset: unknown option: %s\n", param);
@@ -2726,6 +2738,15 @@ printPsetInfo(const char *param, struct printQueryOpt *popt)
 			printf(_("Target width is %d.\n"), popt->topt.columns);
 	}
 
+	/* show the target width for the wrapped format */
+	else if (strcmp(param, "columnfilter") == 0)
+	{
+		if (!popt->topt.columnfilter)
+			printf(_("Column filter is unset.\n"));
+		else
+			printf(_("Column filter is \"%s\".\n"), popt->topt.columnfilter);
+	}
+
 	/* show expanded/vertical mode */
 	else if (strcmp(param, "x") == 0 || strcmp(param, "expanded") == 0 || strcmp(param, "vertical") == 0)
 	{
@@ -2938,6 +2959,8 @@ pset_value_string(const char *param, struct printQueryOpt *popt)
 		return psprintf("%d", popt->topt.border);
 	else if (strcmp(param, "columns") == 0)
 		return psprintf("%d", popt->topt.columns);
+	else if (strcmp(param, "columnfilter") == 0)
+		return pstrdup(popt->topt.columnfilter);
 	else if (strcmp(param, "expanded") == 0)
 		return pstrdup(popt->topt.expanded == 2
 					   ? "auto"
diff --git a/src/bin/psql/print.c b/src/bin/psql/print.c
index ad4350e..9731e54 100644
--- a/src/bin/psql/print.c
+++ b/src/bin/psql/print.c
@@ -195,7 +195,7 @@ static void IsPagerNeeded(const printTableContent *cont, const int extra_lines,
 			  FILE **fout, bool *is_pager);
 
 static void print_aligned_vertical(const printTableContent *cont, FILE *fout);
-
+static char *valfilter(char *filtname, char *origcell, int colnum, int type, bool *mustfree);
 
 /* Count number of digits in integral part of number */
 static int
@@ -3145,6 +3145,86 @@ printTable(const printTableContent *cont, FILE *fout, FILE *flog)
 		ClosePager(fout);
 }
 
+static char *
+valfilter(char *filtname, char *origcell, int colnum, int type, bool *mustfree)
+{
+	char *cmdline;
+	int buflen = strlen(filtname) + 1 +
+		log10(colnum > 0 ? colnum : 1) + 2 + log10(type) + 2 +
+		+ strlen(origcell) + 1 ;
+	FILE *fp;
+	size_t celllen;
+	char *newcell = NULL;
+	char *p;
+	int additional_bytes;
+	bool escape_needed = false;
+
+	/* Check necessity of escaping */
+	for (additional_bytes = 0, p = origcell ; *p ; p++)
+	{
+		if (*p == '\'')
+		{
+			additional_bytes += 4; /* strlen('"'"') - 1 */
+			escape_needed = true;
+		}
+		else if (*p == ' ')
+			escape_needed = true;
+	}
+
+	/* Escaping needed */
+	if (escape_needed)
+	{
+		char *q;
+		char *str;
+		int  newlen;
+
+		additional_bytes += 2;
+		newlen = strlen(origcell) + 1 + additional_bytes;
+		str = (char *)pg_malloc(newlen);
+
+		q = str;
+		*q++ = '\'';
+		for (p = origcell ; *p ; p++)
+		{
+			if (*p == '\'')
+			{
+				strcpy(q, "'\"'\"'");
+				q += 5;
+			}
+			else
+				*q++ = *p;
+		}
+		*q++ = '\'';
+		*q++ = '\0';
+		Assert(q - str == newlen);
+
+		if(*mustfree) free(origcell);
+		origcell = str;
+		*mustfree = true;
+		buflen += additional_bytes;
+	}
+
+	cmdline = pg_malloc(buflen);
+	snprintf(cmdline, buflen, "%s %d %d %s", filtname, type, colnum, origcell);
+	fp = popen(cmdline, "r");
+
+	/* fail silently */
+	if (!fp) return origcell;
+
+	
+	/* receive the result from the filter */
+	if (*mustfree) free(origcell);
+	getline(&newcell, &celllen, fp);  /* POSIX 2008 */
+	fclose(fp);
+	pg_free(cmdline);
+
+	/* chop newlines  */
+	for (p = newcell ; *p && *p != '\n' && *p != '\r' ; p++);
+	*p = 0;
+	*mustfree = true;
+	return newcell;
+}
+
 /*
  * Use this to print query results
  *
@@ -3209,7 +3289,14 @@ printQuery(const PGresult *result, const printQueryOpt *opt, FILE *fout, FILE *f
 				cell = opt->nullPrint ? opt->nullPrint : "";
 			else
 			{
-				cell = PQgetvalue(result, r, c);
+				/* This filter is quite slow */
+				if (opt->topt.columnfilter)
+					cell = valfilter(opt->topt.columnfilter,
+									 PQgetvalue(result, r, c),
+									 c,
+									 PQftype(result, c),
+									 &mustfree);
+				
 				if (cont.aligns[c] == 'r' && opt->topt.numericLocale)
 				{
 					cell = format_numeric_locale(cell);
diff --git a/src/bin/psql/print.h b/src/bin/psql/print.h
index b0b6bf5..5f2e2b3 100644
--- a/src/bin/psql/print.h
+++ b/src/bin/psql/print.h
@@ -109,6 +109,7 @@ typedef struct printTableOpt
 	unicode_linestyle unicode_border_linestyle;
 	unicode_linestyle unicode_column_linestyle;
 	unicode_linestyle unicode_header_linestyle;
+	char *columnfilter;	/* the name of column filter program*/
 } printTableOpt;
 
 /*