Initial jsonpath support

Main TODO
	- indexed arrays [1,4, 6 to 18]
	- variables execution ( $varname )
	- function support
	- ariphmetic support
	- correct error support

It provides two debugging functions: _jsonpath_object and _jsonpath_exist
Some examples are avaliable in src/test/regress/sql/sql_json.sql

Author: feodor

src/backend/Makefile

@@ -139,6 +139,9 @@ storage/lmgr/lwlocknames.h: storage/lmgr/generate-lwlocknames.pl storage/lmgr/lw
 utils/errcodes.h: utils/generate-errcodes.pl utils/errcodes.txt
 	$(MAKE) -C utils errcodes.h
 
+utils/adt/jsonpath_gram.h: utils/adt/jsonpath_gram.y
+	$(MAKE) -C utils/adt jsonpath_gram.h
+
 # see explanation in parser/Makefile
 utils/fmgrprotos.h: utils/fmgroids.h ;
 
@@ -169,7 +172,7 @@ submake-schemapg:
 
 .PHONY: generated-headers
 
-generated-headers: $(top_builddir)/src/include/parser/gram.h $(top_builddir)/src/include/catalog/schemapg.h $(top_builddir)/src/include/storage/lwlocknames.h $(top_builddir)/src/include/utils/errcodes.h $(top_builddir)/src/include/utils/fmgroids.h $(top_builddir)/src/include/utils/fmgrprotos.h $(top_builddir)/src/include/utils/probes.h
+generated-headers: $(top_builddir)/src/include/parser/gram.h $(top_builddir)/src/include/catalog/schemapg.h $(top_builddir)/src/include/storage/lwlocknames.h $(top_builddir)/src/include/utils/errcodes.h $(top_builddir)/src/include/utils/fmgroids.h $(top_builddir)/src/include/utils/fmgrprotos.h $(top_builddir)/src/include/utils/probes.h $(top_builddir)/src/include/utils/jsonpath_gram.h
 
 $(top_builddir)/src/include/parser/gram.h: parser/gram.h
 	prereqdir=`cd '$(dir $<)' >/dev/null && pwd` && \
@@ -186,6 +189,11 @@ $(top_builddir)/src/include/storage/lwlocknames.h: storage/lmgr/lwlocknames.h
 	  cd '$(dir $@)' && rm -f $(notdir $@) && \
 	  $(LN_S) "$$prereqdir/$(notdir $<)" .
 
+$(top_builddir)/src/include/utils/jsonpath_gram.h: utils/adt/jsonpath_gram.h
+	prereqdir=`cd '$(dir $<)' >/dev/null && pwd` && \
+	  cd '$(dir $@)' && rm -f $(notdir $@) && \
+	  $(LN_S) "$$prereqdir/$(notdir $<)" .
+
 $(top_builddir)/src/include/utils/errcodes.h: utils/errcodes.h
 	prereqdir=`cd '$(dir $<)' >/dev/null && pwd` && \
 	  cd '$(dir $@)' && rm -f $(notdir $@) && \
@@ -220,6 +228,7 @@ distprep:
 	$(MAKE) -C replication	repl_gram.c repl_scanner.c syncrep_gram.c syncrep_scanner.c
 	$(MAKE) -C storage/lmgr	lwlocknames.h
 	$(MAKE) -C utils	fmgrtab.c fmgroids.h fmgrprotos.h errcodes.h
+	$(MAKE) -C utils/adt	jsonpath_gram.c jsonpath_gram.h jsonpath_scan.c
 	$(MAKE) -C utils/misc	guc-file.c
 	$(MAKE) -C utils/sort	qsort_tuple.c
 
@@ -308,6 +317,7 @@ endif
 clean:
 	rm -f $(LOCALOBJS) postgres$(X) $(POSTGRES_IMP) \
 		$(top_builddir)/src/include/parser/gram.h \
+		$(top_builddir)/src/include/utils/jsonpath_gram.h \
 		$(top_builddir)/src/include/catalog/schemapg.h \
 		$(top_builddir)/src/include/storage/lwlocknames.h \
 		$(top_builddir)/src/include/utils/fmgroids.h \
@@ -344,6 +354,7 @@ maintainer-clean: distclean
 	      utils/fmgrtab.c \
 	      utils/errcodes.h \
 	      utils/misc/guc-file.c \
+	      utils/adt/jsonpath_gram.h \
 	      utils/sort/qsort_tuple.c
 
 

src/backend/lib/stringinfo.c

@@ -306,3 +306,24 @@ enlargeStringInfo(StringInfo str, int needed)
 
 	str->maxlen = newlen;
 }
+
+/*
+ * alignStringInfoInt - aling StringInfo to int by adding
+ * zero padding bytes
+ */
+void
+alignStringInfoInt(StringInfo buf)
+{
+	switch(INTALIGN(buf->len) - buf->len)
+	{
+		case 3:
+			appendStringInfoCharMacro(buf, 0);
+		case 2:
+			appendStringInfoCharMacro(buf, 0);
+		case 1:
+			appendStringInfoCharMacro(buf, 0);
+		default:
+			break;
+	}
+}
+

src/backend/utils/adt/Makefile

@@ -16,7 +16,8 @@ OBJS = acl.o amutils.o arrayfuncs.o array_expanded.o array_selfuncs.o \
 	float.o format_type.o formatting.o genfile.o \
 	geo_ops.o geo_selfuncs.o geo_spgist.o inet_cidr_ntop.o inet_net_pton.o \
 	int.o int8.o json.o jsonb.o jsonb_gin.o jsonb_op.o jsonb_util.o \
-	jsonfuncs.o like.o lockfuncs.o mac.o mac8.o misc.o nabstime.o name.o \
+	jsonfuncs.o jsonpath_gram.o jsonpath_scan.o jsonpath.o jsonpath_exec.o \
+	like.o lockfuncs.o mac.o mac8.o misc.o nabstime.o name.o \
 	network.o network_gist.o network_selfuncs.o network_spgist.o \
 	numeric.o numutils.o oid.o oracle_compat.o \
 	orderedsetaggs.o pg_locale.o pg_lsn.o pg_upgrade_support.o \
@@ -31,6 +32,26 @@ OBJS = acl.o amutils.o arrayfuncs.o array_expanded.o array_selfuncs.o \
 	txid.o uuid.o varbit.o varchar.o varlena.o version.o \
 	windowfuncs.o xid.o xml.o
 
+# Latest flex causes warnings in this file.
+ifeq ($(GCC),yes)
+scan.o: CFLAGS += -Wno-error
+endif
+
+jsonpath_gram.c: BISONFLAGS += -d
+
+jsonpath_scan.c: FLEXFLAGS = -CF -p -p
+
+jsonpath_gram.h: jsonpath_gram.c ;
+
+# Force these dependencies to be known even without dependency info built:
+jsonpath_gram.o jsonpath_scan.o jsonpath_parser.o: jsonpath_gram.h
+
+# jsonpath_gram.c, jsonpath_gram.h, and jsonpath_scan.c are in the distribution
+# tarball, so they are not cleaned here.
+clean distclean maintainer-clean:
+	rm -f lex.backup
+
+
 like.o: like.c like_match.c
 
 varlena.o: varlena.c levenshtein.c

src/backend/utils/adt/jsonb.c

@@ -1897,3 +1897,24 @@ jsonb_object_agg_finalfn(PG_FUNCTION_ARGS)
 
 	PG_RETURN_POINTER(out);
 }
+
+JsonbValue *
+JsonbExtractScalar(JsonbContainer *jbc, JsonbValue *res)
+{
+	JsonbIterator *it = JsonbIteratorInit(jbc);
+	JsonbIteratorToken tok PG_USED_FOR_ASSERTS_ONLY;
+	JsonbValue	tmp;
+
+	tok = JsonbIteratorNext(&it, &tmp, true);
+	Assert(tok == WJB_BEGIN_ARRAY);
+	Assert(tmp.val.array.nElems == 1 && tmp.val.array.rawScalar);
+
+	tok = JsonbIteratorNext(&it, res, true);
+	Assert (tok == WJB_ELEM);
+	Assert(IsAJsonbScalar(res));
+
+	tok = JsonbIteratorNext(&it, &tmp, true);
+	Assert (tok == WJB_END_ARRAY);
+
+	return res;
+}