[Bf-blender-cvs] [c074943dfd9] blender-v2.90-release: Fix undefined behavior with --debug-xr

[Julian Eisel]

Commit: c074943dfd914fafd25f59cd43e26b4e8ac499f0
Author: Julian Eisel
Date:   Fri Aug 14 16:38:45 2020 +0200
Branches: blender-v2.90-release
https://developer.blender.org/rBc074943dfd914fafd25f59cd43e26b4e8ac499f0

Fix undefined behavior with --debug-xr

Mistake in cb578ca1048d3. Before that, the extension vector was static,
to make sure the extension name strings wouldn't get destructed when
leaving the function. I didn't think that was an issue and couldn't
recreate one, because until the previous commit we wouldn't actually
add any extensions to the vector on Windows (the system I tested
with).

Use C++17's `std::string_view` now, which avoids the string copies
`std::string` creates for itself and thus its destruction when leaving
the local scope.

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

M	intern/ghost/intern/GHOST_XrContext.cpp

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

diff --git a/intern/ghost/intern/GHOST_XrContext.cpp b/intern/ghost/intern/GHOST_XrContext.cpp
index 0d8d42a72f7..3dbf539f0c7 100644
--- a/intern/ghost/intern/GHOST_XrContext.cpp
+++ b/intern/ghost/intern/GHOST_XrContext.cpp
@@ -23,6 +23,7 @@
 #include <cassert>
 #include <sstream>
 #include <string>
+#include <string_view>
 
 #include "GHOST_Types.h"
 #include "GHOST_XrException.h"
@@ -348,7 +349,7 @@ static bool openxr_layer_is_available(const std::vector<XrApiLayerProperties> la
 }
 
 static bool openxr_extension_is_available(const std::vector<XrExtensionProperties> extensions_info,
-                                          const std::string &extension_name)
+                                          const std::string_view &extension_name)
 {
   for (const XrExtensionProperties &ext_info : extensions_info) {
     if (ext_info.extensionName == extension_name) {
@@ -405,7 +406,7 @@ void GHOST_XrContext::getExtensionsToEnable(
     const std::vector<GHOST_TXrGraphicsBinding> &graphics_binding_types,
     std::vector<const char *> &r_ext_names)
 {
-  std::vector<std::string> try_ext;
+  std::vector<std::string_view> try_ext;
 
   /* Try enabling debug extension. */
   if (isDebugMode()) {
@@ -422,9 +423,9 @@ void GHOST_XrContext::getExtensionsToEnable(
     r_ext_names.push_back(gpu_binding);
   }
 
-  for (const std::string &ext : try_ext) {
+  for (const std::string_view &ext : try_ext) {
     if (openxr_extension_is_available(m_oxr->extensions, ext)) {
-      r_ext_names.push_back(ext.c_str());
+      r_ext_names.push_back(ext.data());
     }
   }
 }