IO: Move Abstract Hierarchy Iterator into `io/common`

The goal of the `AbstractHierarchyIterator` class (and supporting
classes) was to use it in different exporters. It shouldn't be part of
the USD module + namespace any more, now that it will also be used in
the upcoming Alembic exporter rewrite.

The source files are moved into `io/common`, which is compiled & linked
into a new library `bf_io_common`. The unittests are still inside the
`tests/gtests/usd` directory. They should be moved to a separate test
module too, but that will be delayed until after T73268 has been
resolved.

Reviewed By: mont29

Differential Revision: https://developer.blender.org/D7669

11 files changed, 75 insertions, 13 deletions

diff --git a/source/blender/io/CMakeLists.txt b/source/blender/io/CMakeLists.txt
index bc2f8d628e2..360cacc4360 100644
--- a/source/blender/io/CMakeLists.txt
+++ b/source/blender/io/CMakeLists.txt
@@ -18,6 +18,8 @@
 # All rights reserved.
 # ***** END GPL LICENSE BLOCK *****
 
+add_subdirectory(common)
+
 if(WITH_ALEMBIC)
   add_subdirectory(alembic)
 endif()
diff --git a/source/blender/io/alembic/CMakeLists.txt b/source/blender/io/alembic/CMakeLists.txt
index 16f2d944876..d864aa51e64 100644
--- a/source/blender/io/alembic/CMakeLists.txt
+++ b/source/blender/io/alembic/CMakeLists.txt
@@ -20,6 +20,7 @@
 
 set(INC
   .
+  ../common
   ../../blenkernel
   ../../blenlib
   ../../blenloader
@@ -92,6 +93,7 @@ set(SRC
 set(LIB
   bf_blenkernel
   bf_blenlib
+  bf_io_common
 
   ${ALEMBIC_LIBRARIES}
   ${OPENEXR_LIBRARIES}
diff --git a/source/blender/io/common/CMakeLists.txt b/source/blender/io/common/CMakeLists.txt
new file mode 100644
index 00000000000..4ed6f12762e
--- /dev/null
+++ b/source/blender/io/common/CMakeLists.txt
@@ -0,0 +1,45 @@
+# ***** BEGIN GPL LICENSE BLOCK *****
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software Foundation,
+# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+#
+# The Original Code is Copyright (C) 2020, Blender Foundation
+# All rights reserved.
+# ***** END GPL LICENSE BLOCK *****
+
+set(INC
+  .
+  ../../blenkernel
+  ../../blenlib
+  ../../depsgraph
+  ../../makesdna
+)
+
+set(INC_SYS
+)
+
+set(SRC
+  intern/abstract_hierarchy_iterator.cc
+
+  IO_abstract_hierarchy_iterator.h
+)
+
+set(LIB
+  bf_blenkernel
+  bf_blenlib
+)
+
+blender_add_lib(bf_io_common "${SRC}" "${INC}" "${INC_SYS}" "${LIB}")
+
+target_link_libraries(bf_io_common INTERFACE)
diff --git a/source/blender/io/usd/intern/abstract_hierarchy_iterator.h b/source/blender/io/common/IO_abstract_hierarchy_iterator.h
index e31d5c91252..480b72ea0cf 100644
--- a/source/blender/io/usd/intern/abstract_hierarchy_iterator.h
+++ b/source/blender/io/common/IO_abstract_hierarchy_iterator.h
@@ -48,7 +48,8 @@ struct Object;
 struct ParticleSystem;
 struct ViewLayer;
 
-namespace USD {
+namespace blender {
+namespace io {
 
 class AbstractHierarchyWriter;
 
@@ -258,6 +259,7 @@ class AbstractHierarchyIterator {
   virtual void delete_object_writer(AbstractHierarchyWriter *writer) = 0;
 };
 
-}  // namespace USD
+}  // namespace io
+}  // namespace blender
 
 #endif /* __ABSTRACT_HIERARCHY_ITERATOR_H__ */
diff --git a/source/blender/io/usd/intern/abstract_hierarchy_iterator.cc b/source/blender/io/common/intern/abstract_hierarchy_iterator.cc
index ab83ea2c3c4..5a318485203 100644
--- a/source/blender/io/usd/intern/abstract_hierarchy_iterator.cc
+++ b/source/blender/io/common/intern/abstract_hierarchy_iterator.cc
@@ -16,7 +16,7 @@
  * The Original Code is Copyright (C) 2019 Blender Foundation.
  * All rights reserved.
  */
-#include "abstract_hierarchy_iterator.h"
+#include "IO_abstract_hierarchy_iterator.h"
 
 #include <iostream>
 #include <limits.h>
@@ -41,7 +41,8 @@
 
 #include "DEG_depsgraph_query.h"
 
-namespace USD {
+namespace blender {
+namespace io {
 
 const HierarchyContext *HierarchyContext::root()
 {
@@ -649,4 +650,5 @@ bool AbstractHierarchyIterator::should_visit_dupli_object(const DupliObject *dup
   return !dupli_object->no_draw;
 }
 
-}  // namespace USD
+}  // namespace io
+}  // namespace blender
diff --git a/source/blender/io/usd/CMakeLists.txt b/source/blender/io/usd/CMakeLists.txt
index 732a638a255..fc4f45cdef8 100644
--- a/source/blender/io/usd/CMakeLists.txt
+++ b/source/blender/io/usd/CMakeLists.txt
@@ -32,6 +32,7 @@ add_definitions(-DPXR_STATIC)
 
 set(INC
   .
+  ../common
   ../../blenkernel
   ../../blenlib
   ../../blenloader
@@ -52,7 +53,6 @@ set(INC_SYS
 )
 
 set(SRC
-  intern/abstract_hierarchy_iterator.cc
   intern/usd_capi.cc
   intern/usd_hierarchy_iterator.cc
   intern/usd_writer_abstract.cc
@@ -64,7 +64,6 @@ set(SRC
   intern/usd_writer_transform.cc
 
   usd.h
-  intern/abstract_hierarchy_iterator.h
   intern/usd_exporter_context.h
   intern/usd_hierarchy_iterator.h
   intern/usd_writer_abstract.h
@@ -79,6 +78,7 @@ set(SRC
 set(LIB
   bf_blenkernel
   bf_blenlib
+  bf_io_common
 )
 
 list(APPEND LIB
diff --git a/source/blender/io/usd/intern/usd_hierarchy_iterator.h b/source/blender/io/usd/intern/usd_hierarchy_iterator.h
index a608012a390..c61a0d2bf07 100644
--- a/source/blender/io/usd/intern/usd_hierarchy_iterator.h
+++ b/source/blender/io/usd/intern/usd_hierarchy_iterator.h
@@ -19,7 +19,7 @@
 #ifndef __USD_HIERARCHY_ITERATOR_H__
 #define __USD_HIERARCHY_ITERATOR_H__
 
-#include "abstract_hierarchy_iterator.h"
+#include "IO_abstract_hierarchy_iterator.h"
 #include "usd.h"
 #include "usd_exporter_context.h"
 
@@ -34,6 +34,10 @@ struct Object;
 
 namespace USD {
 
+using blender::io::AbstractHierarchyIterator;
+using blender::io::AbstractHierarchyWriter;
+using blender::io::HierarchyContext;
+
 class USDHierarchyIterator : public AbstractHierarchyIterator {
  private:
   const pxr::UsdStageRefPtr stage_;
diff --git a/source/blender/io/usd/intern/usd_writer_abstract.h b/source/blender/io/usd/intern/usd_writer_abstract.h
index 01b53f4c916..03c4c263e32 100644
--- a/source/blender/io/usd/intern/usd_writer_abstract.h
+++ b/source/blender/io/usd/intern/usd_writer_abstract.h
@@ -19,7 +19,7 @@
 #ifndef __USD_WRITER_ABSTRACT_H__
 #define __USD_WRITER_ABSTRACT_H__
 
-#include "abstract_hierarchy_iterator.h"
+#include "IO_abstract_hierarchy_iterator.h"
 #include "usd_exporter_context.h"
 
 #include <pxr/usd/sdf/path.h>
@@ -38,6 +38,9 @@ struct Object;
 
 namespace USD {
 
+using blender::io::AbstractHierarchyWriter;
+using blender::io::HierarchyContext;
+
 class USDAbstractWriter : public AbstractHierarchyWriter {
  protected:
   const USDExporterContext usd_export_context_;
diff --git a/tests/gtests/usd/CMakeLists.txt b/tests/gtests/usd/CMakeLists.txt
index 56759f4ccea..d2bfe5e1306 100644
--- a/tests/gtests/usd/CMakeLists.txt
+++ b/tests/gtests/usd/CMakeLists.txt
@@ -35,6 +35,7 @@ set(INC
   ..
   ../../../source/blender/blenlib
   ../../../source/blender/blenkernel
+  ../../../source/blender/io/common
   ../../../source/blender/io/usd
   ../../../source/blender/makesdna
   ../../../source/blender/depsgraph
@@ -52,6 +53,7 @@ set(LIB
   bf_gpu
 
   bf_usd
+  bf_io_common
 
   ${BOOST_LIBRARIES}
   ${TBB_LIBRARIES}
diff --git a/tests/gtests/usd/abstract_hierarchy_iterator_test.cc b/tests/gtests/usd/abstract_hierarchy_iterator_test.cc
index 160dd52f39a..f2e8b09b8d3 100644
--- a/tests/gtests/usd/abstract_hierarchy_iterator_test.cc
+++ b/tests/gtests/usd/abstract_hierarchy_iterator_test.cc
@@ -16,8 +16,8 @@
  * The Original Code is Copyright (C) 2019 Blender Foundation.
  * All rights reserved.
  */
+#include "IO_abstract_hierarchy_iterator.h"
 #include "blenloader/blendfile_loading_base_test.h"
-#include "intern/abstract_hierarchy_iterator.h"
 
 extern "C" {
 #include "BLI_math.h"
@@ -32,7 +32,7 @@ extern "C" {
  * multiple times with different export paths, hence the set. */
 typedef std::map<std::string, std::set<std::string>> created_writers;
 
-using namespace USD;
+using namespace blender::io;
 
 class TestHierarchyWriter : public AbstractHierarchyWriter {
  public:
diff --git a/tests/gtests/usd/hierarchy_context_order_test.cc b/tests/gtests/usd/hierarchy_context_order_test.cc
index 4111fc7511e..25cda6d8670 100644
--- a/tests/gtests/usd/hierarchy_context_order_test.cc
+++ b/tests/gtests/usd/hierarchy_context_order_test.cc
@@ -16,7 +16,7 @@
  * The Original Code is Copyright (C) 2019 Blender Foundation.
  * All rights reserved.
  */
-#include "intern/abstract_hierarchy_iterator.h"
+#include "IO_abstract_hierarchy_iterator.h"
 
 #include "testing/testing.h"
 
@@ -24,7 +24,7 @@ extern "C" {
 #include "BLI_utildefines.h"
 }
 
-using namespace USD;
+using namespace blender::io;
 
 class HierarchyContextOrderTest : public testing::Test {
 };