Github user traflm commented on a diff in the pull request:
https://github.com/apache/incubator-trafodion/pull/833#discussion_r88481672
--- Diff: core/sql/common/ComJSONFuncs.cpp ---
@@ -0,0 +1,793 @@
+/*-------------------------------------------------------------------------
+ *
+ * jsonfuncs.c
+ * Functions to process JSON data types.
+ *
+ * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ * src/backend/utils/adt/jsonfuncs.c
+ *
+ *-------------------------------------------------------------------------
+ */
+/**********************************************************************
+// @@@ START COPYRIGHT @@@
+//
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+//
+// @@@ END COPYRIGHT @@@
+**********************************************************************/
+
+#include "ComJSONStringInfo.h"
+#include "ComJSON.h"
+#include <stdarg.h>
+#include <limits.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include "str.h"
+
+/* semantic action functions for json_get* functions */
+static JsonReturnType get_object_start(void *state);
+static JsonReturnType get_object_end(void *state);
+static JsonReturnType get_object_field_start(void *state, char *fname,
bool isnull);
+static JsonReturnType get_object_field_end(void *state, char *fname, bool
isnull);
+static JsonReturnType get_array_start(void *state);
+static JsonReturnType get_array_end(void *state);
+static JsonReturnType get_array_element_start(void *state, bool isnull);
+static JsonReturnType get_array_element_end(void *state, bool isnull);
+static JsonReturnType get_scalar(void *state, char *token, JsonTokenType
tokentype);
+
+/* common worker function for json getter functions */
+static JsonReturnType get_path_all(bool as_text, char *json, short nargs,
va_list args, char **result);
+static JsonReturnType get_worker(char *json, char **tpath, int *ipath, int
npath,
+ bool normalize_results, char **result);
+
+
+/* semantic action functions for json_array_length */
+static void alen_object_start(void *state);
+static void alen_scalar(void *state, char *token, JsonTokenType tokentype);
+static void alen_array_element_start(void *state, bool isnull);
+
+/* common workers for json{b}_each* functions */
+
+/* semantic action functions for json_each */
+static void each_object_field_start(void *state, char *fname, bool isnull);
+static void each_object_field_end(void *state, char *fname, bool isnull);
+static void each_array_start(void *state);
+static void each_scalar(void *state, char *token, JsonTokenType tokentype);
+
+/* semantic action functions for json_array_elements */
+static void elements_object_start(void *state);
+static void elements_array_element_start(void *state, bool isnull);
+static void elements_array_element_end(void *state, bool isnull);
+static void elements_scalar(void *state, char *token, JsonTokenType
tokentype);
+
+/* semantic action functions for json_strip_nulls */
+static void sn_object_start(void *state);
+static void sn_object_end(void *state);
+static void sn_array_start(void *state);
+static void sn_array_end(void *state);
+static void sn_object_field_start(void *state, char *fname, bool isnull);
+static void sn_array_element_start(void *state, bool isnull);
+static void sn_scalar(void *state, char *token, JsonTokenType tokentype);
+
+/* state for json_object_keys */
+typedef struct OkeysState
+{
+ JsonLexContext *lex;
+ char **result;
+ int result_size;
+ int result_count;
+ int sent_count;
+} OkeysState;
+
+/* state for json_get* functions */
+typedef struct GetState
+{
+ JsonLexContext *lex;
+ char *tresult;
+ char *result_start;
+ bool normalize_results;
+ bool next_scalar;
+ int npath; /* length of each
path-related array */
+ char **path_names; /* field name(s) being sought */
+ int *path_indexes; /* array index(es) being sought
*/
+ bool *pathok; /* is path matched to current
depth? */
+ int *array_cur_index; /* current element index at
each path level */
+} GetState;
+
+/* state for json_array_length */
+typedef struct AlenState
+{
+ JsonLexContext *lex;
+ int count;
+} AlenState;
+
+
+/* state for json_array_elements */
+typedef struct ElementsState
+{
+ JsonLexContext *lex;
+ const char *function_name;
+ char *result_start;
+ bool normalize_results;
+ bool next_scalar;
+ char *normalized_scalar;
+} ElementsState;
+
+/* state for json_strip_nulls */
+typedef struct StripnullState
+{
+ JsonLexContext *lex;
+ StringInfo strval;
+ bool skip_next_null;
+} StripnullState;
+
+JsonReturnType
+json_extract_path(char **result, char *json, short nargs, ...)
+{
+ JsonReturnType ret = JSON_OK;
+ va_list args;
+ va_start(args, nargs);
+ ret = get_path_all(true, json, nargs, args, result);
+ va_end(args);
+ return ret;
+}
+
+JsonReturnType
+json_extract_path_text(char **result, char *json, short nargs, ...)
+{
+ JsonReturnType ret = JSON_OK;
+ va_list args;
+ va_start(args, nargs);
+ ret = get_path_all(true, json, nargs, args, result);
+ va_end(args);
+ return ret;
+}
+
+/*
+ * common routine for extract_path functions
+ */
+static JsonReturnType
+get_path_all(bool as_text, char *json, short nargs, va_list args, char
**result)
+{
+ bool *pathnulls;
+ char **tpath;
+ int *ipath;
+ int i;
+ JsonReturnType ret = JSON_OK;
+
+ tpath = (char **)malloc(nargs * sizeof(char *));
+ ipath = (int *)malloc(nargs * sizeof(int));
+
+ for (i = 0; i < nargs; i++)
+ {
+ tpath[i] = va_arg(args, char *);
+
+ /*
+ * we have no idea at this stage what structure the document is so
+ * just convert anything in the path that we can to an integer and
set
+ * all the other integers to INT_MIN which will never match.
+ */
+ if (*tpath[i] != '\0')
+ {
+ long ind;
+ char *endptr;
+
+ errno = 0;
+ ind = strtol(tpath[i], &endptr, 10);
+ if (*endptr == '\0' && errno == 0 && ind <= INT_MAX && ind >=
INT_MIN)
+ ipath[i] = (int) ind;
+ else
+ ipath[i] = INT_MIN;
+ }
+ else
+ ipath[i] = INT_MIN;
+ }
+
+ ret = get_worker(json, tpath, ipath, nargs, as_text, result);
+
+ if (tpath != NULL)
+ free(tpath);
+ if (ipath != NULL)
+ free(ipath);
+ return ret;
+}
+
+JsonReturnType json_object_field_text(char *json, char *fieldName, char
**result)
+{
+ return get_worker(json, &fieldName, NULL, 1, true, result);
+}
+
+static JsonReturnType
+get_worker(char *json,
+ char **tpath,
+ int *ipath,
+ int npath,
+ bool normalize_results,
+ char **result)
+{
+ JsonLexContext *lex = makeJsonLexContext(json, true);
+ JsonSemAction *sem = (JsonSemAction *)malloc(sizeof(JsonSemAction));
+ GetState *state = (GetState *)malloc(sizeof(GetState));
+ JsonReturnType ret;
+
+ memset(sem, 0, sizeof(JsonSemAction));
+ memset(state, 0, sizeof(GetState));
+
+ if(npath < 0)
+ return JSON_UNEXPECTED_ERROR;
+
+ state->lex = lex;
+ /* is it "_as_text" variant? */
+ state->normalize_results = normalize_results;
+ state->npath = npath;
+ state->path_names = tpath;
+ state->path_indexes = ipath;
+ state->pathok = (bool *)malloc(sizeof(bool) * npath);
+ state->array_cur_index = (int *)malloc(sizeof(int) * npath);
+
+ if (npath > 0)
+ state->pathok[0] = true;
+
+ sem->semstate = (void *) state;
+
+ /*
+ * Not all variants need all the semantic routines. Only set the ones
that
+ * are actually needed for maximum efficiency.
+ */
+ sem->scalar = get_scalar;
+ if (npath == 0)
+ {
+ sem->object_start = get_object_start;
+ sem->object_end = get_object_end;
+ sem->array_start = get_array_start;
+ sem->array_end = get_array_end;
+ }
+ if (tpath != NULL)
+ {
+ sem->object_field_start = get_object_field_start;
+ sem->object_field_end = get_object_field_end;
+ }
+ if (ipath != NULL)
+ {
+ sem->array_start = get_array_start;
+ sem->array_element_start = get_array_element_start;
+ sem->array_element_end = get_array_element_end;
+ }
+
+ ret = pg_parse_json(lex, sem);
+ if (ret == JSON_OK)
+ *result = state->tresult;
+ else
+ *result = NULL;
+
+ if (lex != NULL)
+ {
+ if (lex->strval != NULL)
+ {
+ if (lex->strval->data != NULL)
+ free(lex->strval->data);
+ free(lex->strval);
+ }
+ free(lex);
+ }
+ if (sem != NULL)
+ free(sem);
+ if (state != NULL)
+ free(state);
+ return ret;
+}
+
+static JsonReturnType
+get_object_start(void *state)
+{
+ GetState *_state = (GetState *) state;
+ int lex_level = _state->lex->lex_level;
+
+ if (lex_level == 0 && _state->npath == 0)
+ {
+ /*
+ * Special case: we should match the entire object. We only need
this
+ * at outermost level because at nested levels the match will have
+ * been started by the outer field or array element callback.
+ */
+ _state->result_start = _state->lex->token_start;
+ }
+ return JSON_OK;
+}
+
+static JsonReturnType
+get_object_end(void *state)
+{
+ GetState *_state = (GetState *) state;
+ int lex_level = _state->lex->lex_level;
+
+ if (lex_level == 0 && _state->npath == 0)
+ {
+ /* Special case: return the entire object */
+ char *start = _state->result_start;
+ int len =
_state->lex->prev_token_terminator - start;
+
+ //_state->tresult = cstring_to_text_with_len(start, len);
+ _state->tresult = (char *)malloc(len + 1);
--- End diff --
not clear where this malloc memory will be free?
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