Depsgraph: New dependency graph integration commit

This commit integrates the work done so far on the new dependency graph system,
where goal was to replace legacy depsgraph with the new one, supporting loads of
neat features like:

- More granular dependency relation nature, which solves issues with fake cycles
  in the dependencies.

- Move towards all-animatable, by better integration of drivers into the system.

- Lay down some basis for upcoming copy-on-write, overrides and so on.

The new system is living side-by-side with the previous one and disabled by
default, so nothing will become suddenly broken. The way to enable new depsgraph
is to pass `--new-depsgraph` command line argument.

It's a bit early to consider the system production-ready, there are some TODOs
and issues were discovered during the merge period, they'll be addressed ASAP.
But it's important to merge, because it's the only way to attract artists to
really start testing this system.

There are number of assorted documents related on the design of the new system:

* http://wiki.blender.org/index.php/User:Aligorith/GSoC2013_Depsgraph#Design_Documents
* http://wiki.blender.org/index.php/User:Nazg-gul/DependencyGraph

There are also some user-related information online:

* http://code.blender.org/2015/02/blender-dependency-graph-branch-for-users/
* http://code.blender.org/2015/03/more-dependency-graph-tricks/

Kudos to everyone who was involved into the project:

- Joshua "Aligorith" Leung -- design specification, initial code
- Lukas "lukas_t" Toenne -- integrating code into blender, with further fixes
- Sergey "Sergey" "Sharybin" -- some mocking around, trying to wrap up the
  project and so
- Bassam "slikdigit" Kurdali -- stressing the new system, reporting all the
  issues and recording/writing documentation.
- Everyone else who i forgot to mention here :)

1 files changed, 86 insertions, 0 deletions

diff --git a/source/blender/depsgraph/intern/depsnode_operation.h b/source/blender/depsgraph/intern/depsnode_operation.h
new file mode 100644
index 00000000000..2b70ff0a8dc
--- /dev/null
+++ b/source/blender/depsgraph/intern/depsnode_operation.h
@@ -0,0 +1,86 @@
+/*
+ * ***** 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) 2013 Blender Foundation.
+ * All rights reserved.
+ *
+ * Original Author: Joshua Leung
+ * Contributor(s): None Yet
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+#ifndef __DEPSNODE_OPERATION_H__
+#define __DEPSNODE_OPERATION_H__
+
+#include "depsnode.h"
+
+struct ID;
+
+struct Depsgraph;
+struct DepsgraphCopyContext;
+
+/* Flags for Depsgraph Nodes */
+typedef enum eDepsOperation_Flag {
+	/* node needs to be updated */
+	DEPSOP_FLAG_NEEDS_UPDATE       = (1 << 0),
+
+	/* node was directly modified, causing need for update */
+	/* XXX: intention is to make it easier to tell when we just need to take subgraphs */
+	DEPSOP_FLAG_DIRECTLY_MODIFIED  = (1 << 1),
+
+	/* Operation is evaluated using CPython; has GIL and security implications... */
+	DEPSOP_FLAG_USES_PYTHON   = (1 << 2),
+} eDepsOperation_Flag;
+
+/* Atomic Operation - Base type for all operations */
+struct OperationDepsNode : public DepsNode {
+
+
+	OperationDepsNode();
+	~OperationDepsNode();
+
+	string identifier() const;
+	string full_identifier() const;
+
+	void tag_update(Depsgraph *graph);
+
+	bool is_noop() const { return (bool)evaluate == false; }
+
+	OperationDepsNode *get_entry_operation() { return this; }
+	OperationDepsNode *get_exit_operation() { return this; }
+
+	ComponentDepsNode *owner;     /* component that contains the operation */
+
+	DepsEvalOperationCb evaluate; /* callback for operation */
+
+
+	uint32_t num_links_pending; /* how many inlinks are we still waiting on before we can be evaluated... */
+	float eval_priority;
+	bool scheduled;
+
+	short optype;                 /* (eDepsOperation_Type) stage of evaluation */
+	int   opcode;                 /* (eDepsOperation_Code) identifier for the operation being performed */
+
+	int flag;                     /* (eDepsOperation_Flag) extra settings affecting evaluation */
+
+	DEG_DEPSNODE_DECLARE;
+};
+
+void DEG_register_operation_depsnodes();
+
+#endif  /* __DEPSNODE_OPERATION_H__ */