From 6c5c2bcbd4025cba36f48f6f326466351f4f2971 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Wed, 17 Nov 2021 14:49:56 +0200
Subject: [PATCH] Add validation for mapping buffers

On Vulkan static buffers will be stored on non-host-visible memory and
can't be mapped.  Already-mapped buffers also can't be mapped.
---
 source/backends/opengl/buffer_backend.cpp |  1 -
 source/backends/opengl/buffer_backend.h   |  1 +
 source/core/buffer.cpp                    | 18 ++++++++++++++++++
 source/core/buffer.h                      |  4 ++--
 4 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/source/backends/opengl/buffer_backend.cpp b/source/backends/opengl/buffer_backend.cpp
index ab78b1b5..e0f5525a 100644
--- a/source/backends/opengl/buffer_backend.cpp
+++ b/source/backends/opengl/buffer_backend.cpp
@@ -91,7 +91,6 @@ void *OpenGLBuffer::map()
 
 bool OpenGLBuffer::unmap()
 {
-	// TODO check if it's mapped
 	if(ARB_direct_state_access)
 		return glUnmapNamedBuffer(id);
 	else if(OES_mapbuffer)
diff --git a/source/backends/opengl/buffer_backend.h b/source/backends/opengl/buffer_backend.h
index 1e5106a5..6595ec2a 100644
--- a/source/backends/opengl/buffer_backend.h
+++ b/source/backends/opengl/buffer_backend.h
@@ -24,6 +24,7 @@ protected:
 	void allocate();
 	void sub_data(size_t, size_t, const void *);
 
+	bool can_map() const { return true; }
 	void *map();
 	bool unmap();
 
diff --git a/source/core/buffer.cpp b/source/core/buffer.cpp
index 15a37397..4a36937e 100644
--- a/source/core/buffer.cpp
+++ b/source/core/buffer.cpp
@@ -46,5 +46,23 @@ void Buffer::require_size(size_t req_sz) const
 		throw buffer_too_small(format("buffer has %d bytes; %d required", size, req_sz));
 }
 
+void *Buffer::map()
+{
+	if(!can_map() || mapped)
+		throw invalid_operation("Buffer::map");
+	void *result = BufferBackend::map();
+	mapped = true;
+	return result;
+}
+
+bool Buffer::unmap()
+{
+	if(!can_map() || !mapped)
+		throw invalid_operation("Buffer::map");
+	bool result = BufferBackend::unmap();
+	mapped = false;
+	return result;
+}
+
 } // namespace GL
 } // namespace Msp
diff --git a/source/core/buffer.h b/source/core/buffer.h
index a12b3373..17678fd4 100644
--- a/source/core/buffer.h
+++ b/source/core/buffer.h
@@ -62,8 +62,8 @@ public:
 
 	void require_size(std::size_t) const;
 
-	using BufferBackend::map;
-	using BufferBackend::unmap;
+	void *map();
+	bool unmap();
 
 	using BufferBackend::set_debug_name;
 };
-- 
2.43.0