[Bf-blender-cvs] [6212b73] master: Cycles: Rebuild BVH from scratch if loading cache failed

[Sergey Sharybin]

Commit: 6212b7302cce8f6e2b5f9a0297b9595cf2ad69a8
Author: Sergey Sharybin
Date:   Mon Sep 1 18:03:03 2014 +0600
Branches: master
https://developer.blender.org/rB6212b7302cce8f6e2b5f9a0297b9595cf2ad69a8

Cycles: Rebuild BVH from scratch if loading cache failed

Before this Cycles used to try using the cache even so it knew for the
fact that reading it from the disk failed. This change doesn't make it
more stable if someone will try to trick Cycles and give malformed data
but it solves general cases when Blender crashed during the cache write
and will preserve rendering from crashing when trying to use that partial
cache.

===================================================================

M	intern/cycles/bvh/bvh.cpp
M	intern/cycles/util/util_cache.h

===================================================================

diff --git a/intern/cycles/bvh/bvh.cpp b/intern/cycles/bvh/bvh.cpp
index 3c0c5c0..15bd814 100644
--- a/intern/cycles/bvh/bvh.cpp
+++ b/intern/cycles/bvh/bvh.cpp
@@ -103,18 +103,30 @@ bool BVH::cache_read(CacheData& key)
 	if(Cache::global.lookup(key, value)) {
 		cache_filename = key.get_filename();
 
-		value.read(pack.root_index);
-		value.read(pack.SAH);
-
-		value.read(pack.nodes);
-		value.read(pack.object_node);
-		value.read(pack.tri_woop);
-		value.read(pack.prim_type);
-		value.read(pack.prim_visibility);
-		value.read(pack.prim_index);
-		value.read(pack.prim_object);
-		value.read(pack.is_leaf);
-
+		if(!(value.read(pack.root_index) &&
+		     value.read(pack.SAH) &&
+		     value.read(pack.nodes) &&
+		     value.read(pack.object_node) &&
+		     value.read(pack.tri_woop) &&
+		     value.read(pack.prim_type) &&
+		     value.read(pack.prim_visibility) &&
+		     value.read(pack.prim_index) &&
+		     value.read(pack.prim_object) &&
+		     value.read(pack.is_leaf)))
+		{
+			/* Clear the pack if load failed. */
+			pack.root_index = 0;
+			pack.SAH = 0.0f;
+			pack.nodes.clear();
+			pack.object_node.clear();
+			pack.tri_woop.clear();
+			pack.prim_type.clear();
+			pack.prim_visibility.clear();
+			pack.prim_index.clear();
+			pack.prim_object.clear();
+			pack.is_leaf.clear();
+			return false;
+		}
 		return true;
 	}
 
diff --git a/intern/cycles/util/util_cache.h b/intern/cycles/util/util_cache.h
index c6752d9..bfb2877 100644
--- a/intern/cycles/util/util_cache.h
+++ b/intern/cycles/util/util_cache.h
@@ -96,54 +96,70 @@ public:
 		buffers.push_back(buffer);
 	}
 
-	template<typename T> void read(array<T>& data)
+	template<typename T> bool read(array<T>& data)
 	{
 		size_t size;
 
 		if(!fread(&size, sizeof(size), 1, f)) {
 			fprintf(stderr, "Failed to read vector size from cache.\n");
-			return;
+			return false;
 		}
 
 		if(!size)
-			return;
+			return false;
 
 		data.resize(size/sizeof(T));
 
 		if(!fread(&data[0], size, 1, f)) {
 			fprintf(stderr, "Failed to read vector data from cache (%lu).\n", (unsigned long)size);
-			return;
+			return false;
 		}
+		return true;
 	}
 
-	void read(int& data)
+	bool read(int& data)
 	{
 		size_t size;
 
-		if(!fread(&size, sizeof(size), 1, f))
+		if(!fread(&size, sizeof(size), 1, f)) {
 			fprintf(stderr, "Failed to read int size from cache.\n");
-		if(!fread(&data, sizeof(data), 1, f))
+			return false;
+		}
+		if(!fread(&data, sizeof(data), 1, f)) {
 			fprintf(stderr, "Failed to read int from cache.\n");
+			return false;
+		}
+		return true;
 	}
 
-	void read(float& data)
+	bool read(float& data)
 	{
 		size_t size;
 
-		if(!fread(&size, sizeof(size), 1, f))
+		if(!fread(&size, sizeof(size), 1, f)) {
 			fprintf(stderr, "Failed to read float size from cache.\n");
-		if(!fread(&data, sizeof(data), 1, f))
+			return false;
+		}
+		if(!fread(&data, sizeof(data), 1, f)) {
 			fprintf(stderr, "Failed to read float from cache.\n");
+			return false;
+		}
+		return true;
 	}
 
-	void read(size_t& data)
+	bool read(size_t& data)
 	{
 		size_t size;
 
-		if(!fread(&size, sizeof(size), 1, f))
+		if(!fread(&size, sizeof(size), 1, f)) {
 			fprintf(stderr, "Failed to read size_t size from cache.\n");
-		if(!fread(&data, sizeof(data), 1, f))
+			return false;
+		}
+		if(!fread(&data, sizeof(data), 1, f)) {
 			fprintf(stderr, "Failed to read size_t from cache.\n");
+			return false;
+		}
+		return true;
 	}
 };