Add DECLARE STATEMENT support to ECPG.

DECLARE STATEMENT is a statement that lets users declare an identifier
pointing at a connection.  This identifier will be used in other embedded
dynamic SQL statement such as PREPARE, EXECUTE, DECLARE CURSOR and so on.
When connecting to a non-default connection, the AT clause can be used in
a DECLARE STATEMENT once and is no longer needed in every dynamic SQL
statement.  This makes ECPG applications easier and more efficient.  Moreover,
writing code without designating connection explicitly improves portability.

Authors: Ideriha-san ("Ideriha, Takeshi" <ideriha.takeshi@jp.fujitsu.com>)
         Kuroda-san ("Kuroda, Hayato" <kuroda.hayato@jp.fujitsu.com>)

Discussion: https://postgr.es/m4E72940DA2BF16479384A86D54D0988A565669DF@G01JPEXMBKW04

1 files changed, 65 insertions, 21 deletions

diff --git a/src/interfaces/ecpg/preproc/ecpg.c b/src/interfaces/ecpg/preproc/ecpg.c
index 4e4528b0aa3..a6a43f5a3f7 100644
--- a/src/interfaces/ecpg/preproc/ecpg.c
+++ b/src/interfaces/ecpg/preproc/ecpg.c
@@ -28,6 +28,7 @@ struct _include_path *include_paths = NULL;
 struct cursor *cur = NULL;
 struct typedefs *types = NULL;
 struct _defines *defines = NULL;
+struct declared_name_st *g_declared_list = NULL;
 
 static void
 help(const char *progname)
@@ -111,6 +112,48 @@ add_preprocessor_define(char *define)
 	defines->next = pd;
 }
 
+static void
+free_argument(struct arguments *arg)
+{
+	if (arg == NULL)
+		return;
+
+	free_argument(arg->next);
+
+	/*
+	 *  Don't free variables in it because the original codes don't free it either
+	 *  variables are static structures instead of allocating
+	 */
+	free(arg);
+}
+
+static void
+free_cursor(struct cursor *c)
+{
+	if (c == NULL)
+		return;
+
+	free_cursor(c->next);
+	free_argument(c->argsinsert);
+	free_argument(c->argsresult);
+
+	free(c->name);
+	free(c->function);
+	free(c->command);
+	free(c->prepared_name);
+	free(c);
+}
+
+static void
+free_declared_stmt(struct declared_name_st *st)
+{
+	if (st == NULL)
+		return;
+
+	free_declared_stmt(st->next);
+	free(st);
+}
+
 #define ECPG_GETOPT_LONG_REGRESSION		1
 int
 main(int argc, char *const argv[])
@@ -348,29 +391,18 @@ main(int argc, char *const argv[])
 				struct typedefs *typeptr;
 
 				/* remove old cursor definitions if any are still there */
-				for (ptr = cur; ptr != NULL;)
+				if (cur)
 				{
-					struct cursor *this = ptr;
-					struct arguments *l1,
-							   *l2;
-
-					free(ptr->command);
-					free(ptr->connection);
-					free(ptr->name);
-					for (l1 = ptr->argsinsert; l1; l1 = l2)
-					{
-						l2 = l1->next;
-						free(l1);
-					}
-					for (l1 = ptr->argsresult; l1; l1 = l2)
-					{
-						l2 = l1->next;
-						free(l1);
-					}
-					ptr = ptr->next;
-					free(this);
+					free_cursor(cur);
+					cur = NULL;
+				}
+
+				/* remove old declared statements if any are still there */
+				if (g_declared_list)
+				{
+					free_declared_stmt(g_declared_list);
+					g_declared_list = NULL;
 				}
-				cur = NULL;
 
 				/* remove non-pertinent old defines as well */
 				while (defines && !defines->pertinent)
@@ -487,6 +519,18 @@ main(int argc, char *const argv[])
 
 			free(input_filename);
 		}
+
+		if(g_declared_list)
+		{
+			free_declared_stmt(g_declared_list);
+			g_declared_list = NULL;
+		}
+
+		if(cur)
+		{
+			free_cursor(cur);
+			cur = NULL;
+		}
 	}
 	return ret_value;
 }