1 files changed, 131 insertions, 0 deletions
diff --git a/src/backend/utils/adt/quote.c b/src/backend/utils/adt/quote.c
new file mode 100644
index 0000000..8de4eac
--- /dev/null
+++ b/src/backend/utils/adt/quote.c
@@ -0,0 +1,131 @@
+/*-------------------------------------------------------------------------
+ *
+ * quote.c
+ *	  Functions for quoting identifiers and literals
+ *
+ * Portions Copyright (c) 2000-2021, PostgreSQL Global Development Group
+ *
+ *
+ * IDENTIFICATION
+ *	  src/backend/utils/adt/quote.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "utils/builtins.h"
+
+
+/*
+ * quote_ident -
+ *	  returns a properly quoted identifier
+ */
+Datum
+quote_ident(PG_FUNCTION_ARGS)
+{
+	text	   *t = PG_GETARG_TEXT_PP(0);
+	const char *qstr;
+	char	   *str;
+
+	str = text_to_cstring(t);
+	qstr = quote_identifier(str);
+	PG_RETURN_TEXT_P(cstring_to_text(qstr));
+}
+
+/*
+ * quote_literal_internal -
+ *	  helper function for quote_literal and quote_literal_cstr
+ *
+ * NOTE: think not to make this function's behavior change with
+ * standard_conforming_strings.  We don't know where the result
+ * literal will be used, and so we must generate a result that
+ * will work with either setting.  Take a look at what dblink
+ * uses this for before thinking you know better.
+ */
+static size_t
+quote_literal_internal(char *dst, const char *src, size_t len)
+{
+	const char *s;
+	char	   *savedst = dst;
+
+	for (s = src; s < src + len; s++)
+	{
+		if (*s == '\\')
+		{
+			*dst++ = ESCAPE_STRING_SYNTAX;
+			break;
+		}
+	}
+
+	*dst++ = '\'';
+	while (len-- > 0)
+	{
+		if (SQL_STR_DOUBLE(*src, true))
+			*dst++ = *src;
+		*dst++ = *src++;
+	}
+	*dst++ = '\'';
+
+	return dst - savedst;
+}
+
+/*
+ * quote_literal -
+ *	  returns a properly quoted literal
+ */
+Datum
+quote_literal(PG_FUNCTION_ARGS)
+{
+	text	   *t = PG_GETARG_TEXT_PP(0);
+	text	   *result;
+	char	   *cp1;
+	char	   *cp2;
+	int			len;
+
+	len = VARSIZE_ANY_EXHDR(t);
+	/* We make a worst-case result area; wasting a little space is OK */
+	result = (text *) palloc(len * 2 + 3 + VARHDRSZ);
+
+	cp1 = VARDATA_ANY(t);
+	cp2 = VARDATA(result);
+
+	SET_VARSIZE(result, VARHDRSZ + quote_literal_internal(cp2, cp1, len));
+
+	PG_RETURN_TEXT_P(result);
+}
+
+/*
+ * quote_literal_cstr -
+ *	  returns a properly quoted literal
+ */
+char *
+quote_literal_cstr(const char *rawstr)
+{
+	char	   *result;
+	int			len;
+	int			newlen;
+
+	len = strlen(rawstr);
+	/* We make a worst-case result area; wasting a little space is OK */
+	result = palloc(len * 2 + 3 + 1);
+
+	newlen = quote_literal_internal(result, rawstr, len);
+	result[newlen] = '\0';
+
+	return result;
+}
+
+/*
+ * quote_nullable -
+ *	  Returns a properly quoted literal, with null values returned
+ *	  as the text string 'NULL'.
+ */
+Datum
+quote_nullable(PG_FUNCTION_ARGS)
+{
+	if (PG_ARGISNULL(0))
+		PG_RETURN_TEXT_P(cstring_to_text("NULL"));
+	else
+		PG_RETURN_DATUM(DirectFunctionCall1(quote_literal,
+											PG_GETARG_DATUM(0)));
+}