ECPG: Start tracking subtransactions and cursors in the runtime

library to reduce network turnaround.

For this purpose, the arguments to ECPGtrans() have changed and
4 new public functions were introduced: ECPGopen(), ECPGfetch(),
ECPGcursor_dml() and ECPGclose(). The previously exposed ecpg_do()
is used to drive all these functions. The library version was
changed to 7.0 from 6.6 because of the ECPGtrans change.

New error handling is added to mimic the server behaviour if a
previous function checking the savepoint or cursor name failed.

A new regression test was added to exercise certain aspects of
the client-side tracking of cursors and subtransactions.

doc/src/sgml/ecpg.sgml

@@ -5273,6 +5273,16 @@ while (1)
      </listitem>
     </varlistentry>
 
+    <varlistentry>
+     <term>-231 (<symbol>ECPG_INVALID_CURSOR</symbol>)</term>
+     <listitem>
+      <para>
+       The cursor name you are trying to use is invalid.
+       (SQLSTATE 34000)
+      </para>
+     </listitem>
+    </varlistentry>
+
     <varlistentry>
      <term>-239 (<symbol>ECPG_INFORMIX_DUPLICATE_KEY</symbol>)</term>
      <listitem>
@@ -5359,11 +5369,24 @@ while (1)
     <varlistentry>
      <term>-401 (<symbol>ECPG_TRANS</symbol>)</term>
      <listitem>
+      <para>
+       This error code may occur in the following conditions.
+      </para>
       <para>
        The <productname>PostgreSQL</productname> server signaled that
        we cannot start, commit, or rollback the transaction.
        (SQLSTATE 08007)
       </para>
+      <para>
+       While processing a previous command, a client side error happened:
+       invalid savepoint name or invalid cursor name. The actual command
+       was not sent to the server because of this error. To mimic the
+       server behaviour, all subsequent commands return the error for
+       an aborted transaction. (SQLSTATE 25P02)
+      </para>
+      <para>
+       The savepoint name you are trying to use is invalid. (SQLSTATE 3B001)
+      </para>
      </listitem>
     </varlistentry>
 

src/interfaces/ecpg/ecpglib/Makefile

@@ -14,8 +14,8 @@ top_builddir = ../../../..
 include $(top_builddir)/src/Makefile.global
 
 NAME= ecpg
-SO_MAJOR_VERSION= 6
-SO_MINOR_VERSION= 6
+SO_MAJOR_VERSION= 7
+SO_MINOR_VERSION= 0
 
 override CPPFLAGS := -I../include -I$(top_srcdir)/src/interfaces/ecpg/include \
 	-I$(libpq_srcdir) -I$(top_builddir)/src/port $(CPPFLAGS)
@@ -25,7 +25,7 @@ override CFLAGS += $(PTHREAD_CFLAGS)
 LIBS := $(filter-out -lpgport, $(LIBS))
 
 OBJS= execute.o typename.o descriptor.o sqlda.o data.o error.o prepare.o memory.o \
-	connect.o misc.o path.o pgstrcasecmp.o \
+	connect.o misc.o path.o cursor.o pgstrcasecmp.o \
 	$(filter snprintf.o strlcpy.o win32setlocale.o isinf.o, $(LIBOBJS))
 
 # thread.c is needed only for non-WIN32 implementation of path.c

src/interfaces/ecpg/ecpglib/connect.c

@@ -475,6 +475,9 @@ ECPGconnect(int lineno, int c, const char *name, const char *user, const char *p
 
 	this->cache_head = NULL;
 	this->prep_stmts = NULL;
+	this->subxact_desc = NULL;
+	this->cursor_desc = NULL;
+	this->client_side_error = false;
 
 	if (all_connections == NULL)
 		this->next = NULL;