Move jsonapi.c and jsonapi.h to src/common.

To make this work, (1) makeJsonLexContextCstringLen now takes the
encoding to be used as an argument; (2) check_stack_depth() is made to
do nothing in frontend code, and (3) elog(ERROR, ...) is changed to
pg_log_fatal + exit in frontend code.

Mark Dilger, reviewed and slightly revised by me.

Discussion: http://postgr.es/m/CA+TgmoYfOXhd27MUDGioVh6QtpD0C1K-f6ObSA10AWiHBAL5bA@mail.gmail.com

1 files changed, 0 insertions, 1096 deletions

diff --git a/src/backend/utils/adt/jsonapi.c b/src/backend/utils/adt/jsonapi.c
deleted file mode 100644
index 230a55b1013..00000000000
--- a/src/backend/utils/adt/jsonapi.c
+++ /dev/null
@@ -1,1096 +0,0 @@
-/*-------------------------------------------------------------------------
- *
- * jsonapi.c
- *		JSON parser and lexer interfaces
- *
- * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
- * Portions Copyright (c) 1994, Regents of the University of California
- *
- * IDENTIFICATION
- *	  src/backend/utils/adt/jsonapi.c
- *
- *-------------------------------------------------------------------------
- */
-#include "postgres.h"
-
-#include "mb/pg_wchar.h"
-#include "miscadmin.h"
-#include "utils/jsonapi.h"
-
-/*
- * The context of the parser is maintained by the recursive descent
- * mechanism, but is passed explicitly to the error reporting routine
- * for better diagnostics.
- */
-typedef enum					/* contexts of JSON parser */
-{
-	JSON_PARSE_VALUE,			/* expecting a value */
-	JSON_PARSE_STRING,			/* expecting a string (for a field name) */
-	JSON_PARSE_ARRAY_START,		/* saw '[', expecting value or ']' */
-	JSON_PARSE_ARRAY_NEXT,		/* saw array element, expecting ',' or ']' */
-	JSON_PARSE_OBJECT_START,	/* saw '{', expecting label or '}' */
-	JSON_PARSE_OBJECT_LABEL,	/* saw object label, expecting ':' */
-	JSON_PARSE_OBJECT_NEXT,		/* saw object value, expecting ',' or '}' */
-	JSON_PARSE_OBJECT_COMMA,	/* saw object ',', expecting next label */
-	JSON_PARSE_END				/* saw the end of a document, expect nothing */
-} JsonParseContext;
-
-static inline JsonParseErrorType json_lex_string(JsonLexContext *lex);
-static inline JsonParseErrorType json_lex_number(JsonLexContext *lex, char *s,
-								   bool *num_err, int *total_len);
-static inline JsonParseErrorType parse_scalar(JsonLexContext *lex, JsonSemAction *sem);
-static JsonParseErrorType parse_object_field(JsonLexContext *lex, JsonSemAction *sem);
-static JsonParseErrorType parse_object(JsonLexContext *lex, JsonSemAction *sem);
-static JsonParseErrorType parse_array_element(JsonLexContext *lex, JsonSemAction *sem);
-static JsonParseErrorType parse_array(JsonLexContext *lex, JsonSemAction *sem);
-static JsonParseErrorType report_parse_error(JsonParseContext ctx, JsonLexContext *lex);
-static char *extract_token(JsonLexContext *lex);
-
-/* the null action object used for pure validation */
-JsonSemAction nullSemAction =
-{
-	NULL, NULL, NULL, NULL, NULL,
-	NULL, NULL, NULL, NULL, NULL
-};
-
-/* Recursive Descent parser support routines */
-
-/*
- * lex_peek
- *
- * what is the current look_ahead token?
-*/
-static inline JsonTokenType
-lex_peek(JsonLexContext *lex)
-{
-	return lex->token_type;
-}
-
-/*
- * lex_expect
- *
- * move the lexer to the next token if the current look_ahead token matches
- * the parameter token. Otherwise, report an error.
- */
-static inline JsonParseErrorType
-lex_expect(JsonParseContext ctx, JsonLexContext *lex, JsonTokenType token)
-{
-	if (lex_peek(lex) == token)
-		return json_lex(lex);
-	else
-		return report_parse_error(ctx, lex);
-}
-
-/* chars to consider as part of an alphanumeric token */
-#define JSON_ALPHANUMERIC_CHAR(c)  \
-	(((c) >= 'a' && (c) <= 'z') || \
-	 ((c) >= 'A' && (c) <= 'Z') || \
-	 ((c) >= '0' && (c) <= '9') || \
-	 (c) == '_' || \
-	 IS_HIGHBIT_SET(c))
-
-/*
- * Utility function to check if a string is a valid JSON number.
- *
- * str is of length len, and need not be null-terminated.
- */
-bool
-IsValidJsonNumber(const char *str, int len)
-{
-	bool		numeric_error;
-	int			total_len;
-	JsonLexContext dummy_lex;
-
-	if (len <= 0)
-		return false;
-
-	/*
-	 * json_lex_number expects a leading  '-' to have been eaten already.
-	 *
-	 * having to cast away the constness of str is ugly, but there's not much
-	 * easy alternative.
-	 */
-	if (*str == '-')
-	{
-		dummy_lex.input = unconstify(char *, str) +1;
-		dummy_lex.input_length = len - 1;
-	}
-	else
-	{
-		dummy_lex.input = unconstify(char *, str);
-		dummy_lex.input_length = len;
-	}
-
-	json_lex_number(&dummy_lex, dummy_lex.input, &numeric_error, &total_len);
-
-	return (!numeric_error) && (total_len == dummy_lex.input_length);
-}
-
-/*
- * makeJsonLexContextCstringLen
- *
- * lex constructor, with or without StringInfo object for de-escaped lexemes.
- *
- * Without is better as it makes the processing faster, so only make one
- * if really required.
- */
-JsonLexContext *
-makeJsonLexContextCstringLen(char *json, int len, bool need_escapes)
-{
-	JsonLexContext *lex = palloc0(sizeof(JsonLexContext));
-
-	lex->input = lex->token_terminator = lex->line_start = json;
-	lex->line_number = 1;
-	lex->input_length = len;
-	if (need_escapes)
-		lex->strval = makeStringInfo();
-	return lex;
-}
-
-/*
- * pg_parse_json
- *
- * Publicly visible entry point for the JSON parser.
- *
- * lex is a lexing context, set up for the json to be processed by calling
- * makeJsonLexContext(). sem is a structure of function pointers to semantic
- * action routines to be called at appropriate spots during parsing, and a
- * pointer to a state object to be passed to those routines.
- */
-JsonParseErrorType
-pg_parse_json(JsonLexContext *lex, JsonSemAction *sem)
-{
-	JsonTokenType tok;
-	JsonParseErrorType	result;
-
-	/* get the initial token */
-	result = json_lex(lex);
-	if (result != JSON_SUCCESS)
-		return result;
-
-	tok = lex_peek(lex);
-
-	/* parse by recursive descent */
-	switch (tok)
-	{
-		case JSON_TOKEN_OBJECT_START:
-			result = parse_object(lex, sem);
-			break;
-		case JSON_TOKEN_ARRAY_START:
-			result = parse_array(lex, sem);
-			break;
-		default:
-			result = parse_scalar(lex, sem); /* json can be a bare scalar */
-	}
-
-	if (result == JSON_SUCCESS)
-		result = lex_expect(JSON_PARSE_END, lex, JSON_TOKEN_END);
-
-	return result;
-}
-
-/*
- * json_count_array_elements
- *
- * Returns number of array elements in lex context at start of array token
- * until end of array token at same nesting level.
- *
- * Designed to be called from array_start routines.
- */
-JsonParseErrorType
-json_count_array_elements(JsonLexContext *lex, int *elements)
-{
-	JsonLexContext copylex;
-	int			count;
-	JsonParseErrorType	result;
-
-	/*
-	 * It's safe to do this with a shallow copy because the lexical routines
-	 * don't scribble on the input. They do scribble on the other pointers
-	 * etc, so doing this with a copy makes that safe.
-	 */
-	memcpy(&copylex, lex, sizeof(JsonLexContext));
-	copylex.strval = NULL;		/* not interested in values here */
-	copylex.lex_level++;
-
-	count = 0;
-	result = lex_expect(JSON_PARSE_ARRAY_START, &copylex,
-						JSON_TOKEN_ARRAY_START);
-	if (result != JSON_SUCCESS)
-		return result;
-	if (lex_peek(&copylex) != JSON_TOKEN_ARRAY_END)
-	{
-		while (1)
-		{
-			count++;
-			result = parse_array_element(&copylex, &nullSemAction);
-			if (result != JSON_SUCCESS)
-				return result;
-			if (copylex.token_type != JSON_TOKEN_COMMA)
-				break;
-			result = json_lex(&copylex);
-			if (result != JSON_SUCCESS)
-				return result;
-		}
-	}
-	result = lex_expect(JSON_PARSE_ARRAY_NEXT, &copylex,
-							JSON_TOKEN_ARRAY_END);
-	if (result != JSON_SUCCESS)
-		return result;
-
-	*elements = count;
-	return JSON_SUCCESS;
-}
-
-/*
- *	Recursive Descent parse routines. There is one for each structural
- *	element in a json document:
- *	  - scalar (string, number, true, false, null)
- *	  - array  ( [ ] )
- *	  - array element
- *	  - object ( { } )
- *	  - object field
- */
-static inline JsonParseErrorType
-parse_scalar(JsonLexContext *lex, JsonSemAction *sem)
-{
-	char	   *val = NULL;
-	json_scalar_action sfunc = sem->scalar;
-	JsonTokenType tok = lex_peek(lex);
-	JsonParseErrorType result;
-
-	/* a scalar must be a string, a number, true, false, or null */
-	if (tok != JSON_TOKEN_STRING && tok != JSON_TOKEN_NUMBER &&
-		tok != JSON_TOKEN_TRUE && tok != JSON_TOKEN_FALSE &&
-		tok != JSON_TOKEN_NULL)
-		return report_parse_error(JSON_PARSE_VALUE, lex);
-
-	/* if no semantic function, just consume the token */
-	if (sfunc == NULL)
-		return json_lex(lex);
-
-	/* extract the de-escaped string value, or the raw lexeme */
-	if (lex_peek(lex) == JSON_TOKEN_STRING)
-	{
-		if (lex->strval != NULL)
-			val = pstrdup(lex->strval->data);
-	}
-	else
-	{
-		int			len = (lex->token_terminator - lex->token_start);
-
-		val = palloc(len + 1);
-		memcpy(val, lex->token_start, len);
-		val[len] = '\0';
-	}
-
-	/* consume the token */
-	result = json_lex(lex);
-	if (result != JSON_SUCCESS)
-		return result;
-
-	/* invoke the callback */
-	(*sfunc) (sem->semstate, val, tok);
-
-	return JSON_SUCCESS;
-}
-
-static JsonParseErrorType
-parse_object_field(JsonLexContext *lex, JsonSemAction *sem)
-{
-	/*
-	 * An object field is "fieldname" : value where value can be a scalar,
-	 * object or array.  Note: in user-facing docs and error messages, we
-	 * generally call a field name a "key".
-	 */
-
-	char	   *fname = NULL;	/* keep compiler quiet */
-	json_ofield_action ostart = sem->object_field_start;
-	json_ofield_action oend = sem->object_field_end;
-	bool		isnull;
-	JsonTokenType tok;
-	JsonParseErrorType result;
-
-	if (lex_peek(lex) != JSON_TOKEN_STRING)
-		return report_parse_error(JSON_PARSE_STRING, lex);
-	if ((ostart != NULL || oend != NULL) && lex->strval != NULL)
-		fname = pstrdup(lex->strval->data);
-	result = json_lex(lex);
-	if (result != JSON_SUCCESS)
-		return result;
-
-	result = lex_expect(JSON_PARSE_OBJECT_LABEL, lex, JSON_TOKEN_COLON);
-	if (result != JSON_SUCCESS)
-		return result;
-
-	tok = lex_peek(lex);
-	isnull = tok == JSON_TOKEN_NULL;
-
-	if (ostart != NULL)
-		(*ostart) (sem->semstate, fname, isnull);
-
-	switch (tok)
-	{
-		case JSON_TOKEN_OBJECT_START:
-			result = parse_object(lex, sem);
-			break;
-		case JSON_TOKEN_ARRAY_START:
-			result = parse_array(lex, sem);
-			break;
-		default:
-			result = parse_scalar(lex, sem);
-	}
-	if (result != JSON_SUCCESS)
-		return result;
-
-	if (oend != NULL)
-		(*oend) (sem->semstate, fname, isnull);
-	return JSON_SUCCESS;
-}
-
-static JsonParseErrorType
-parse_object(JsonLexContext *lex, JsonSemAction *sem)
-{
-	/*
-	 * an object is a possibly empty sequence of object fields, separated by
-	 * commas and surrounded by curly braces.
-	 */
-	json_struct_action ostart = sem->object_start;
-	json_struct_action oend = sem->object_end;
-	JsonTokenType tok;
-	JsonParseErrorType result;
-
-	check_stack_depth();
-
-	if (ostart != NULL)
-		(*ostart) (sem->semstate);
-
-	/*
-	 * Data inside an object is at a higher nesting level than the object
-	 * itself. Note that we increment this after we call the semantic routine
-	 * for the object start and restore it before we call the routine for the
-	 * object end.
-	 */
-	lex->lex_level++;
-
-	Assert(lex_peek(lex) == JSON_TOKEN_OBJECT_START);
-	result = json_lex(lex);
-	if (result != JSON_SUCCESS)
-		return result;
-
-	tok = lex_peek(lex);
-	switch (tok)
-	{
-		case JSON_TOKEN_STRING:
-			result = parse_object_field(lex, sem);
-			while (result == JSON_SUCCESS && lex_peek(lex) == JSON_TOKEN_COMMA)
-			{
-				result = json_lex(lex);
-				if (result != JSON_SUCCESS)
-					break;
-				result = parse_object_field(lex, sem);
-			}
-			break;
-		case JSON_TOKEN_OBJECT_END:
-			break;
-		default:
-			/* case of an invalid initial token inside the object */
-			result = report_parse_error(JSON_PARSE_OBJECT_START, lex);
-	}
-	if (result != JSON_SUCCESS)
-		return result;
-
-	result = lex_expect(JSON_PARSE_OBJECT_NEXT, lex, JSON_TOKEN_OBJECT_END);
-	if (result != JSON_SUCCESS)
-		return result;
-
-	lex->lex_level--;
-
-	if (oend != NULL)
-		(*oend) (sem->semstate);
-
-	return JSON_SUCCESS;
-}
-
-static JsonParseErrorType
-parse_array_element(JsonLexContext *lex, JsonSemAction *sem)
-{
-	json_aelem_action astart = sem->array_element_start;
-	json_aelem_action aend = sem->array_element_end;
-	JsonTokenType tok = lex_peek(lex);
-	JsonParseErrorType result;
-
-	bool		isnull;
-
-	isnull = tok == JSON_TOKEN_NULL;
-
-	if (astart != NULL)
-		(*astart) (sem->semstate, isnull);
-
-	/* an array element is any object, array or scalar */
-	switch (tok)
-	{
-		case JSON_TOKEN_OBJECT_START:
-			result = parse_object(lex, sem);
-			break;
-		case JSON_TOKEN_ARRAY_START:
-			result = parse_array(lex, sem);
-			break;
-		default:
-			result = parse_scalar(lex, sem);
-	}
-
-	if (result != JSON_SUCCESS)
-		return result;
-
-	if (aend != NULL)
-		(*aend) (sem->semstate, isnull);
-
-	return JSON_SUCCESS;
-}
-
-static JsonParseErrorType
-parse_array(JsonLexContext *lex, JsonSemAction *sem)
-{
-	/*
-	 * an array is a possibly empty sequence of array elements, separated by
-	 * commas and surrounded by square brackets.
-	 */
-	json_struct_action astart = sem->array_start;
-	json_struct_action aend = sem->array_end;
-	JsonParseErrorType result;
-
-	check_stack_depth();
-
-	if (astart != NULL)
-		(*astart) (sem->semstate);
-
-	/*
-	 * Data inside an array is at a higher nesting level than the array
-	 * itself. Note that we increment this after we call the semantic routine
-	 * for the array start and restore it before we call the routine for the
-	 * array end.
-	 */
-	lex->lex_level++;
-
-	result = lex_expect(JSON_PARSE_ARRAY_START, lex, JSON_TOKEN_ARRAY_START);
-	if (result == JSON_SUCCESS && lex_peek(lex) != JSON_TOKEN_ARRAY_END)
-	{
-		result = parse_array_element(lex, sem);
-
-		while (result == JSON_SUCCESS && lex_peek(lex) == JSON_TOKEN_COMMA)
-		{
-			result = json_lex(lex);
-			if (result != JSON_SUCCESS)
-				break;
-			result = parse_array_element(lex, sem);
-		}
-	}
-	if (result != JSON_SUCCESS)
-		return result;
-
-	result = lex_expect(JSON_PARSE_ARRAY_NEXT, lex, JSON_TOKEN_ARRAY_END);
-	if (result != JSON_SUCCESS)
-		return result;
-
-	lex->lex_level--;
-
-	if (aend != NULL)
-		(*aend) (sem->semstate);
-
-	return JSON_SUCCESS;
-}
-
-/*
- * Lex one token from the input stream.
- */
-JsonParseErrorType
-json_lex(JsonLexContext *lex)
-{
-	char	   *s;
-	int			len;
-	JsonParseErrorType	result;
-
-	/* Skip leading whitespace. */
-	s = lex->token_terminator;
-	len = s - lex->input;
-	while (len < lex->input_length &&
-		   (*s == ' ' || *s == '\t' || *s == '\n' || *s == '\r'))
-	{
-		if (*s == '\n')
-			++lex->line_number;
-		++s;
-		++len;
-	}
-	lex->token_start = s;
-
-	/* Determine token type. */
-	if (len >= lex->input_length)
-	{
-		lex->token_start = NULL;
-		lex->prev_token_terminator = lex->token_terminator;
-		lex->token_terminator = s;
-		lex->token_type = JSON_TOKEN_END;
-	}
-	else
-	{
-		switch (*s)
-		{
-				/* Single-character token, some kind of punctuation mark. */
-			case '{':
-				lex->prev_token_terminator = lex->token_terminator;
-				lex->token_terminator = s + 1;
-				lex->token_type = JSON_TOKEN_OBJECT_START;
-				break;
-			case '}':
-				lex->prev_token_terminator = lex->token_terminator;
-				lex->token_terminator = s + 1;
-				lex->token_type = JSON_TOKEN_OBJECT_END;
-				break;
-			case '[':
-				lex->prev_token_terminator = lex->token_terminator;
-				lex->token_terminator = s + 1;
-				lex->token_type = JSON_TOKEN_ARRAY_START;
-				break;
-			case ']':
-				lex->prev_token_terminator = lex->token_terminator;
-				lex->token_terminator = s + 1;
-				lex->token_type = JSON_TOKEN_ARRAY_END;
-				break;
-			case ',':
-				lex->prev_token_terminator = lex->token_terminator;
-				lex->token_terminator = s + 1;
-				lex->token_type = JSON_TOKEN_COMMA;
-				break;
-			case ':':
-				lex->prev_token_terminator = lex->token_terminator;
-				lex->token_terminator = s + 1;
-				lex->token_type = JSON_TOKEN_COLON;
-				break;
-			case '"':
-				/* string */
-				result = json_lex_string(lex);
-				if (result != JSON_SUCCESS)
-					return result;
-				lex->token_type = JSON_TOKEN_STRING;
-				break;
-			case '-':
-				/* Negative number. */
-				result = json_lex_number(lex, s + 1, NULL, NULL);
-				if (result != JSON_SUCCESS)
-					return result;
-				lex->token_type = JSON_TOKEN_NUMBER;
-				break;
-			case '0':
-			case '1':
-			case '2':
-			case '3':
-			case '4':
-			case '5':
-			case '6':
-			case '7':
-			case '8':
-			case '9':
-				/* Positive number. */
-				result = json_lex_number(lex, s, NULL, NULL);
-				if (result != JSON_SUCCESS)
-					return result;
-				lex->token_type = JSON_TOKEN_NUMBER;
-				break;
-			default:
-				{
-					char	   *p;
-
-					/*
-					 * We're not dealing with a string, number, legal
-					 * punctuation mark, or end of string.  The only legal
-					 * tokens we might find here are true, false, and null,
-					 * but for error reporting purposes we scan until we see a
-					 * non-alphanumeric character.  That way, we can report
-					 * the whole word as an unexpected token, rather than just
-					 * some unintuitive prefix thereof.
-					 */
-					for (p = s; p - s < lex->input_length - len && JSON_ALPHANUMERIC_CHAR(*p); p++)
-						 /* skip */ ;
-
-					/*
-					 * We got some sort of unexpected punctuation or an
-					 * otherwise unexpected character, so just complain about
-					 * that one character.
-					 */
-					if (p == s)
-					{
-						lex->prev_token_terminator = lex->token_terminator;
-						lex->token_terminator = s + 1;
-						return JSON_INVALID_TOKEN;
-					}
-
-					/*
-					 * We've got a real alphanumeric token here.  If it
-					 * happens to be true, false, or null, all is well.  If
-					 * not, error out.
-					 */
-					lex->prev_token_terminator = lex->token_terminator;
-					lex->token_terminator = p;
-					if (p - s == 4)
-					{
-						if (memcmp(s, "true", 4) == 0)
-							lex->token_type = JSON_TOKEN_TRUE;
-						else if (memcmp(s, "null", 4) == 0)
-							lex->token_type = JSON_TOKEN_NULL;
-						else
-							return JSON_INVALID_TOKEN;
-					}
-					else if (p - s == 5 && memcmp(s, "false", 5) == 0)
-						lex->token_type = JSON_TOKEN_FALSE;
-					else
-						return JSON_INVALID_TOKEN;
-
-				}
-		}						/* end of switch */
-	}
-
-	return JSON_SUCCESS;
-}
-
-/*
- * The next token in the input stream is known to be a string; lex it.
- */
-static inline JsonParseErrorType
-json_lex_string(JsonLexContext *lex)
-{
-	char	   *s;
-	int			len;
-	int			hi_surrogate = -1;
-
-	if (lex->strval != NULL)
-		resetStringInfo(lex->strval);
-
-	Assert(lex->input_length > 0);
-	s = lex->token_start;
-	len = lex->token_start - lex->input;
-	for (;;)
-	{
-		s++;
-		len++;
-		/* Premature end of the string. */
-		if (len >= lex->input_length)
-		{
-			lex->token_terminator = s;
-			return JSON_INVALID_TOKEN;
-		}
-		else if (*s == '"')
-			break;
-		else if ((unsigned char) *s < 32)
-		{
-			/* Per RFC4627, these characters MUST be escaped. */
-			/* Since *s isn't printable, exclude it from the context string */
-			lex->token_terminator = s;
-			return JSON_ESCAPING_REQUIRED;
-		}
-		else if (*s == '\\')
-		{
-			/* OK, we have an escape character. */
-			s++;
-			len++;
-			if (len >= lex->input_length)
-			{
-				lex->token_terminator = s;
-				return JSON_INVALID_TOKEN;
-			}
-			else if (*s == 'u')
-			{
-				int			i;
-				int			ch = 0;
-
-				for (i = 1; i <= 4; i++)
-				{
-					s++;
-					len++;
-					if (len >= lex->input_length)
-					{
-						lex->token_terminator = s;
-						return JSON_INVALID_TOKEN;
-					}
-					else if (*s >= '0' && *s <= '9')
-						ch = (ch * 16) + (*s - '0');
-					else if (*s >= 'a' && *s <= 'f')
-						ch = (ch * 16) + (*s - 'a') + 10;
-					else if (*s >= 'A' && *s <= 'F')
-						ch = (ch * 16) + (*s - 'A') + 10;
-					else
-					{
-						lex->token_terminator = s + pg_mblen(s);
-						return JSON_UNICODE_ESCAPE_FORMAT;
-					}
-				}
-				if (lex->strval != NULL)
-				{
-					char		utf8str[5];
-					int			utf8len;
-
-					if (ch >= 0xd800 && ch <= 0xdbff)
-					{
-						if (hi_surrogate != -1)
-							return JSON_UNICODE_HIGH_SURROGATE;
-						hi_surrogate = (ch & 0x3ff) << 10;
-						continue;
-					}
-					else if (ch >= 0xdc00 && ch <= 0xdfff)
-					{
-						if (hi_surrogate == -1)
-							return JSON_UNICODE_LOW_SURROGATE;
-						ch = 0x10000 + hi_surrogate + (ch & 0x3ff);
-						hi_surrogate = -1;
-					}
-
-					if (hi_surrogate != -1)
-						return JSON_UNICODE_LOW_SURROGATE;
-
-					/*
-					 * For UTF8, replace the escape sequence by the actual
-					 * utf8 character in lex->strval. Do this also for other
-					 * encodings if the escape designates an ASCII character,
-					 * otherwise raise an error.
-					 */
-
-					if (ch == 0)
-					{
-						/* We can't allow this, since our TEXT type doesn't */
-						return JSON_UNICODE_CODE_POINT_ZERO;
-					}
-					else if (GetDatabaseEncoding() == PG_UTF8)
-					{
-						unicode_to_utf8(ch, (unsigned char *) utf8str);
-						utf8len = pg_utf_mblen((unsigned char *) utf8str);
-						appendBinaryStringInfo(lex->strval, utf8str, utf8len);
-					}
-					else if (ch <= 0x007f)
-					{
-						/*
-						 * This is the only way to designate things like a
-						 * form feed character in JSON, so it's useful in all
-						 * encodings.
-						 */
-						appendStringInfoChar(lex->strval, (char) ch);
-					}
-					else
-						return JSON_UNICODE_HIGH_ESCAPE;
-
-				}
-			}
-			else if (lex->strval != NULL)
-			{
-				if (hi_surrogate != -1)
-					return JSON_UNICODE_LOW_SURROGATE;
-
-				switch (*s)
-				{
-					case '"':
-					case '\\':
-					case '/':
-						appendStringInfoChar(lex->strval, *s);
-						break;
-					case 'b':
-						appendStringInfoChar(lex->strval, '\b');
-						break;
-					case 'f':
-						appendStringInfoChar(lex->strval, '\f');
-						break;
-					case 'n':
-						appendStringInfoChar(lex->strval, '\n');
-						break;
-					case 'r':
-						appendStringInfoChar(lex->strval, '\r');
-						break;
-					case 't':
-						appendStringInfoChar(lex->strval, '\t');
-						break;
-					default:
-						/* Not a valid string escape, so signal error. */
-						lex->token_start = s;
-						lex->token_terminator = s + pg_mblen(s);
-						return JSON_ESCAPING_INVALID;
-				}
-			}
-			else if (strchr("\"\\/bfnrt", *s) == NULL)
-			{
-				/*
-				 * Simpler processing if we're not bothered about de-escaping
-				 *
-				 * It's very tempting to remove the strchr() call here and
-				 * replace it with a switch statement, but testing so far has
-				 * shown it's not a performance win.
-				 */
-				lex->token_start = s;
-				lex->token_terminator = s + pg_mblen(s);
-				return JSON_ESCAPING_INVALID;
-			}
-
-		}
-		else if (lex->strval != NULL)
-		{
-			if (hi_surrogate != -1)
-				return JSON_UNICODE_LOW_SURROGATE;
-
-			appendStringInfoChar(lex->strval, *s);
-		}
-
-	}
-
-	if (hi_surrogate != -1)
-		return JSON_UNICODE_LOW_SURROGATE;
-
-	/* Hooray, we found the end of the string! */
-	lex->prev_token_terminator = lex->token_terminator;
-	lex->token_terminator = s + 1;
-	return JSON_SUCCESS;
-}
-
-/*
- * The next token in the input stream is known to be a number; lex it.
- *
- * In JSON, a number consists of four parts:
- *
- * (1) An optional minus sign ('-').
- *
- * (2) Either a single '0', or a string of one or more digits that does not
- *	   begin with a '0'.
- *
- * (3) An optional decimal part, consisting of a period ('.') followed by
- *	   one or more digits.  (Note: While this part can be omitted
- *	   completely, it's not OK to have only the decimal point without
- *	   any digits afterwards.)
- *
- * (4) An optional exponent part, consisting of 'e' or 'E', optionally
- *	   followed by '+' or '-', followed by one or more digits.  (Note:
- *	   As with the decimal part, if 'e' or 'E' is present, it must be
- *	   followed by at least one digit.)
- *
- * The 's' argument to this function points to the ostensible beginning
- * of part 2 - i.e. the character after any optional minus sign, or the
- * first character of the string if there is none.
- *
- * If num_err is not NULL, we return an error flag to *num_err rather than
- * raising an error for a badly-formed number.  Also, if total_len is not NULL
- * the distance from lex->input to the token end+1 is returned to *total_len.
- */
-static inline JsonParseErrorType
-json_lex_number(JsonLexContext *lex, char *s,
-				bool *num_err, int *total_len)
-{
-	bool		error = false;
-	int			len = s - lex->input;
-
-	/* Part (1): leading sign indicator. */
-	/* Caller already did this for us; so do nothing. */
-
-	/* Part (2): parse main digit string. */
-	if (len < lex->input_length && *s == '0')
-	{
-		s++;
-		len++;
-	}
-	else if (len < lex->input_length && *s >= '1' && *s <= '9')
-	{
-		do
-		{
-			s++;
-			len++;
-		} while (len < lex->input_length && *s >= '0' && *s <= '9');
-	}
-	else
-		error = true;
-
-	/* Part (3): parse optional decimal portion. */
-	if (len < lex->input_length && *s == '.')
-	{
-		s++;
-		len++;
-		if (len == lex->input_length || *s < '0' || *s > '9')
-			error = true;
-		else
-		{
-			do
-			{
-				s++;
-				len++;
-			} while (len < lex->input_length && *s >= '0' && *s <= '9');
-		}
-	}
-
-	/* Part (4): parse optional exponent. */
-	if (len < lex->input_length && (*s == 'e' || *s == 'E'))
-	{
-		s++;
-		len++;
-		if (len < lex->input_length && (*s == '+' || *s == '-'))
-		{
-			s++;
-			len++;
-		}
-		if (len == lex->input_length || *s < '0' || *s > '9')
-			error = true;
-		else
-		{
-			do
-			{
-				s++;
-				len++;
-			} while (len < lex->input_length && *s >= '0' && *s <= '9');
-		}
-	}
-
-	/*
-	 * Check for trailing garbage.  As in json_lex(), any alphanumeric stuff
-	 * here should be considered part of the token for error-reporting
-	 * purposes.
-	 */
-	for (; len < lex->input_length && JSON_ALPHANUMERIC_CHAR(*s); s++, len++)
-		error = true;
-
-	if (total_len != NULL)
-		*total_len = len;
-
-	if (num_err != NULL)
-	{
-		/* let the caller handle any error */
-		*num_err = error;
-	}
-	else
-	{
-		/* return token endpoint */
-		lex->prev_token_terminator = lex->token_terminator;
-		lex->token_terminator = s;
-		/* handle error if any */
-		if (error)
-			return JSON_INVALID_TOKEN;
-	}
-
-	return JSON_SUCCESS;
-}
-
-/*
- * Report a parse error.
- *
- * lex->token_start and lex->token_terminator must identify the current token.
- */
-static JsonParseErrorType
-report_parse_error(JsonParseContext ctx, JsonLexContext *lex)
-{
-	/* Handle case where the input ended prematurely. */
-	if (lex->token_start == NULL || lex->token_type == JSON_TOKEN_END)
-		return JSON_EXPECTED_MORE;
-
-	/* Otherwise choose the error type based on the parsing context. */
-	switch (ctx)
-	{
-		case JSON_PARSE_END:
-			return JSON_EXPECTED_END;
-		case JSON_PARSE_VALUE:
-			return JSON_EXPECTED_JSON;
-		case JSON_PARSE_STRING:
-			return JSON_EXPECTED_STRING;
-		case JSON_PARSE_ARRAY_START:
-			return JSON_EXPECTED_ARRAY_FIRST;
-		case JSON_PARSE_ARRAY_NEXT:
-			return JSON_EXPECTED_ARRAY_NEXT;
-		case JSON_PARSE_OBJECT_START:
-			return JSON_EXPECTED_OBJECT_FIRST;
-		case JSON_PARSE_OBJECT_LABEL:
-			return JSON_EXPECTED_COLON;
-		case JSON_PARSE_OBJECT_NEXT:
-			return JSON_EXPECTED_OBJECT_NEXT;
-		case JSON_PARSE_OBJECT_COMMA:
-			return JSON_EXPECTED_STRING;
-	}
-
-	/*
-	 * We don't use a default: case, so that the compiler will warn about
-	 * unhandled enum values.  But this needs to be here anyway to cover the
-	 * possibility of an incorrect input.
-	 */
-	elog(ERROR, "unexpected json parse state: %d", (int) ctx);
-	return JSON_SUCCESS;		/* silence stupider compilers */
-}
-
-/*
- * Construct a detail message for a JSON error.
- */
-char *
-json_errdetail(JsonParseErrorType error, JsonLexContext *lex)
-{
-	switch (error)
-	{
-		case JSON_SUCCESS:
-			/* fall through to the error code after switch */
-			break;
-		case JSON_ESCAPING_INVALID:
-			return psprintf(_("Escape sequence \"\\%s\" is invalid."),
-							extract_token(lex));
-		case JSON_ESCAPING_REQUIRED:
-			return psprintf(_("Character with value 0x%02x must be escaped."),
-							(unsigned char) *(lex->token_terminator));
-		case JSON_EXPECTED_END:
-			return psprintf(_("Expected end of input, but found \"%s\"."),
-							extract_token(lex));
-		case JSON_EXPECTED_ARRAY_FIRST:
-			return psprintf(_("Expected array element or \"]\", but found \"%s\"."),
-							extract_token(lex));
-		case JSON_EXPECTED_ARRAY_NEXT:
-			return psprintf(_("Expected \",\" or \"]\", but found \"%s\"."),
-							extract_token(lex));
-		case JSON_EXPECTED_COLON:
-			return psprintf(_("Expected \":\", but found \"%s\"."),
-							extract_token(lex));
-		case JSON_EXPECTED_JSON:
-			return psprintf(_("Expected JSON value, but found \"%s\"."),
-							extract_token(lex));
-		case JSON_EXPECTED_MORE:
-			return _("The input string ended unexpectedly.");
-		case JSON_EXPECTED_OBJECT_FIRST:
-			return psprintf(_("Expected string or \"}\", but found \"%s\"."),
-							extract_token(lex));
-		case JSON_EXPECTED_OBJECT_NEXT:
-			return psprintf(_("Expected \",\" or \"}\", but found \"%s\"."),
-							extract_token(lex));
-		case JSON_EXPECTED_STRING:
-			return psprintf(_("Expected string, but found \"%s\"."),
-							extract_token(lex));
-		case JSON_INVALID_TOKEN:
-			return psprintf(_("Token \"%s\" is invalid."),
-							extract_token(lex));
-		case JSON_UNICODE_CODE_POINT_ZERO:
-			return _("\\u0000 cannot be converted to text.");
-		case JSON_UNICODE_ESCAPE_FORMAT:
-			return _("\"\\u\" must be followed by four hexadecimal digits.");
-		case JSON_UNICODE_HIGH_ESCAPE:
-			return _("Unicode escape values cannot be used for code point values above 007F when the server encoding is not UTF8.");
-		case JSON_UNICODE_HIGH_SURROGATE:
-			return _("Unicode high surrogate must not follow a high surrogate.");
-		case JSON_UNICODE_LOW_SURROGATE:
-			return _("Unicode low surrogate must follow a high surrogate.");
-	}
-
-	/*
-	 * We don't use a default: case, so that the compiler will warn about
-	 * unhandled enum values.  But this needs to be here anyway to cover the
-	 * possibility of an incorrect input.
-	 */
-	elog(ERROR, "unexpected json parse error type: %d", (int) error);
-	return NULL;				/* silence stupider compilers */
-}
-
-/*
- * Extract the current token from a lexing context, for error reporting.
- */
-static char *
-extract_token(JsonLexContext *lex)
-{
-	int toklen = lex->token_terminator - lex->token_start;
-	char *token = palloc(toklen + 1);
-
-	memcpy(token, lex->token_start, toklen);
-	token[toklen] = '\0';
-	return token;
-}