Generalize varobj iterator

This patch generalizes varobj iterator, in a python-independent way.
Note varobj_item is still a typedef of PyObject, we can only focus on
API changes, and leave the data type changes to the next patch.  As a
result, we include "varobj-iter.h" after the typedef of PyObject in
varobj.c, but it is an intermediate state.  Finally, varobj-iter.h is
independent of PyObject.

This change is helpful to move some python-related code out of
varobj.c.

 V2:
  - Fix a missing cleanup.
  - Fix typos.
  - Use XNEW.
  - Check against NULL explicitly.
  - Update copyright year for new added files.

 V3:
  - Call PyGILState_Ensure before Py_XDECREF.
  - Use CPYCHECKER_STEALS_REFERENCE_TO_ARG.
  - Code indentation.

 V4:
  - use varobj_ensure_python_env instead of PyGILState_Ensure.

gdb:

2014-06-12  Pedro Alves  <pedro@codesourcery.com>
	    Yao Qi  <yao@codesourcery.com>

	* Makefile.in (SUBDIR_PYTHON_OBS): Add "py-varobj.o".
	(SUBDIR_PYTHON_SRCS): Add "python/py-varobj.c".
	(HFILES_NO_SRCDIR): Add "varobj-iter.h".
	(py-varobj.o): New rule.
	* python/py-varobj.c: New file.
	* python/python-internal.h (py_varobj_get_iterator): Declare.
	* varobj-iter.h: New file.
	* varobj.c: Include "varobj-iter.h"
	(struct varobj) <child_iter>: Change its type from "PyObject *"
	to "struct varobj_iter *".
	<saved_item>: Likewise.
	[HAVE_PYTHON] (varobj_ensure_python_env): Make it extern.
	[HAVE_PYTHON] (varobj_get_iterator): New function.
	(update_dynamic_varobj_children) [HAVE_PYTHON]: Move
	python-specific code to python/py-varobj.c.
	(install_visualizer): Call varobj_iter_delete instead of
	Py_XDECREF.
	* varobj.h (varobj_ensure_python_env): Declare.

1 files changed, 10 insertions, 3 deletions

diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index ea27cf5..deb64a1 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -376,7 +376,8 @@ SUBDIR_PYTHON_OBS = \
 	py-threadevent.o \
 	py-type.o \
 	py-utils.o \
-	py-value.o
+	py-value.o \
+	py-varobj.o
 
 SUBDIR_PYTHON_SRCS = \
 	python/python.c \
@@ -413,7 +414,8 @@ SUBDIR_PYTHON_SRCS = \
 	python/py-threadevent.c \
 	python/py-type.c \
 	python/py-utils.c \
-	python/py-value.c
+	python/py-value.c \
+	python/py-varobj.c
 SUBDIR_PYTHON_DEPS =
 SUBDIR_PYTHON_LDFLAGS=
 SUBDIR_PYTHON_CFLAGS=
@@ -865,7 +867,8 @@ proc-utils.h aarch64-tdep.h arm-tdep.h ax-gdb.h ppcfbsd-tdep.h \
 ppcnbsd-tdep.h cli-out.h gdb_expat.h breakpoint.h infcall.h obsd-tdep.h \
 exec.h m32r-tdep.h osabi.h gdbcore.h solib-som.h amd64bsd-nat.h \
 i386bsd-nat.h xml-support.h xml-tdesc.h alphabsd-tdep.h gdb_obstack.h \
-ia64-tdep.h ada-lang.h varobj.h frv-tdep.h nto-tdep.h serial.h \
+ia64-tdep.h ada-lang.h ada-varobj.h varobj.h varobj-iter.h frv-tdep.h \
+nto-tdep.h serial.h \
 c-lang.h d-lang.h go-lang.h frame.h event-loop.h block.h cli/cli-setshow.h \
 cli/cli-decode.h cli/cli-cmds.h cli/cli-utils.h \
 cli/cli-script.h macrotab.h symtab.h common/version.h \
@@ -2506,6 +2509,10 @@ py-value.o: $(srcdir)/python/py-value.c
 	$(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/py-value.c
 	$(POSTCOMPILE)
 
+py-varobj.o: $(srcdir)/python/py-varobj.c
+	$(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/py-varobj.c
+	$(POSTCOMPILE)
+
 #
 # Dependency tracking.  Most of this is conditional on GNU Make being
 # found by configure; if GNU Make is not found, we fall back to a