1 files changed, 169 insertions, 0 deletions
diff --git a/src/include/common/jsonapi.h b/src/include/common/jsonapi.h
new file mode 100644
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--- /dev/null
+++ b/src/include/common/jsonapi.h
@@ -0,0 +1,169 @@
+/*-------------------------------------------------------------------------
+ *
+ * jsonapi.h
+ *	  Declarations for JSON API support.
+ *
+ * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/utils/jsonapi.h
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#ifndef JSONAPI_H
+#define JSONAPI_H
+
+#include "lib/stringinfo.h"
+
+typedef enum
+{
+	JSON_TOKEN_INVALID,
+	JSON_TOKEN_STRING,
+	JSON_TOKEN_NUMBER,
+	JSON_TOKEN_OBJECT_START,
+	JSON_TOKEN_OBJECT_END,
+	JSON_TOKEN_ARRAY_START,
+	JSON_TOKEN_ARRAY_END,
+	JSON_TOKEN_COMMA,
+	JSON_TOKEN_COLON,
+	JSON_TOKEN_TRUE,
+	JSON_TOKEN_FALSE,
+	JSON_TOKEN_NULL,
+	JSON_TOKEN_END
+} JsonTokenType;
+
+typedef enum
+{
+	JSON_SUCCESS,
+	JSON_ESCAPING_INVALID,
+	JSON_ESCAPING_REQUIRED,
+	JSON_EXPECTED_ARRAY_FIRST,
+	JSON_EXPECTED_ARRAY_NEXT,
+	JSON_EXPECTED_COLON,
+	JSON_EXPECTED_END,
+	JSON_EXPECTED_JSON,
+	JSON_EXPECTED_MORE,
+	JSON_EXPECTED_OBJECT_FIRST,
+	JSON_EXPECTED_OBJECT_NEXT,
+	JSON_EXPECTED_STRING,
+	JSON_INVALID_TOKEN,
+	JSON_UNICODE_CODE_POINT_ZERO,
+	JSON_UNICODE_ESCAPE_FORMAT,
+	JSON_UNICODE_HIGH_ESCAPE,
+	JSON_UNICODE_HIGH_SURROGATE,
+	JSON_UNICODE_LOW_SURROGATE
+} JsonParseErrorType;
+
+
+/*
+ * All the fields in this structure should be treated as read-only.
+ *
+ * If strval is not null, then it should contain the de-escaped value
+ * of the lexeme if it's a string. Otherwise most of these field names
+ * should be self-explanatory.
+ *
+ * line_number and line_start are principally for use by the parser's
+ * error reporting routines.
+ * token_terminator and prev_token_terminator point to the character
+ * AFTER the end of the token, i.e. where there would be a nul byte
+ * if we were using nul-terminated strings.
+ */
+typedef struct JsonLexContext
+{
+	char	   *input;
+	int			input_length;
+	int			input_encoding;
+	char	   *token_start;
+	char	   *token_terminator;
+	char	   *prev_token_terminator;
+	JsonTokenType token_type;
+	int			lex_level;
+	int			line_number;
+	char	   *line_start;
+	StringInfo	strval;
+} JsonLexContext;
+
+typedef void (*json_struct_action) (void *state);
+typedef void (*json_ofield_action) (void *state, char *fname, bool isnull);
+typedef void (*json_aelem_action) (void *state, bool isnull);
+typedef void (*json_scalar_action) (void *state, char *token, JsonTokenType tokentype);
+
+
+/*
+ * Semantic Action structure for use in parsing json.
+ * Any of these actions can be NULL, in which case nothing is done at that
+ * point, Likewise, semstate can be NULL. Using an all-NULL structure amounts
+ * to doing a pure parse with no side-effects, and is therefore exactly
+ * what the json input routines do.
+ *
+ * The 'fname' and 'token' strings passed to these actions are palloc'd.
+ * They are not free'd or used further by the parser, so the action function
+ * is free to do what it wishes with them.
+ */
+typedef struct JsonSemAction
+{
+	void	   *semstate;
+	json_struct_action object_start;
+	json_struct_action object_end;
+	json_struct_action array_start;
+	json_struct_action array_end;
+	json_ofield_action object_field_start;
+	json_ofield_action object_field_end;
+	json_aelem_action array_element_start;
+	json_aelem_action array_element_end;
+	json_scalar_action scalar;
+} JsonSemAction;
+
+/*
+ * pg_parse_json will parse the string in the lex calling the
+ * action functions in sem at the appropriate points. It is
+ * up to them to keep what state they need	in semstate. If they
+ * need access to the state of the lexer, then its pointer
+ * should be passed to them as a member of whatever semstate
+ * points to. If the action pointers are NULL the parser
+ * does nothing and just continues.
+ */
+extern JsonParseErrorType pg_parse_json(JsonLexContext *lex,
+										JsonSemAction *sem);
+
+/* the null action object used for pure validation */
+extern JsonSemAction nullSemAction;
+
+/*
+ * json_count_array_elements performs a fast secondary parse to determine the
+ * number of elements in passed array lex context. It should be called from an
+ * array_start action.
+ *
+ * The return value indicates whether any error occurred, while the number
+ * of elements is stored into *elements (but only if the return value is
+ * JSON_SUCCESS).
+ */
+extern JsonParseErrorType json_count_array_elements(JsonLexContext *lex,
+													int *elements);
+
+/*
+ * constructor for JsonLexContext, with or without strval element.
+ * If supplied, the strval element will contain a de-escaped version of
+ * the lexeme. However, doing this imposes a performance penalty, so
+ * it should be avoided if the de-escaped lexeme is not required.
+ */
+extern JsonLexContext *makeJsonLexContextCstringLen(char *json,
+													int len,
+													int encoding,
+													bool need_escapes);
+
+/* lex one token */
+extern JsonParseErrorType json_lex(JsonLexContext *lex);
+
+/* construct an error detail string for a json error */
+extern char *json_errdetail(JsonParseErrorType error, JsonLexContext *lex);
+
+/*
+ * Utility function to check if a string is a valid JSON number.
+ *
+ * str argument does not need to be nul-terminated.
+ */
+extern bool IsValidJsonNumber(const char *str, int len);
+
+#endif							/* JSONAPI_H */