A sad workaround for a sad misery with Python bindings on Windows.

mosra · Oct 23, 2019 · 01d8cdd · 01d8cdd
1 parent d47bc8f
commit 01d8cdd
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Showing 6 changed files with 15 additions and 8 deletions.
diff --git a/doc/corrade-changelog.dox b/doc/corrade-changelog.dox
@@ -186,6 +186,8 @@ namespace Corrade {
 -   Global state used by @ref PluginManager::Manager, @ref Utility::Debug and
     @ref Utility::Resource internals is no longer duplicated when Corrade is
     built statically and linked to more than one dynamic library or executable.
+    This works on all platforms except for Python bindings on Windows at the
+    moment, where the workaround is to build Corrade dynamically.
 -   @ref PluginManager::Manager and @ref Utility::Debug now have the global
     state thread-local when the @ref CORRADE_BUILD_MULTITHREADED option is
     enabled (see also [mosra/corrade#65](https://github.com/mosra/corrade/issues/65))

diff --git a/src/Corrade/PluginManager/AbstractManager.cpp b/src/Corrade/PluginManager/AbstractManager.cpp
@@ -219,14 +219,14 @@ namespace {
 Implementation::StaticPlugin*& windowsGlobalStaticPlugins() {
     /* A function-local static to ensure it's only initialized once without any
        race conditions among threads */
-    static Implementation::StaticPlugin** const uniqueGlobals = reinterpret_cast<Implementation::StaticPlugin**>(Utility::Implementation::windowsWeakSymbol("corradePluginManagerUniqueGlobalStaticPlugins"));
+    static Implementation::StaticPlugin** const uniqueGlobals = reinterpret_cast<Implementation::StaticPlugin**>(Utility::Implementation::windowsWeakSymbol("corradePluginManagerUniqueGlobalStaticPlugins", &corradePluginManagerUniqueGlobalStaticPlugins));
     return *uniqueGlobals;
 }
 
 std::map<std::string, AbstractManager::Plugin*>*& windowsGlobalPlugins() {
     /* A function-local static to ensure it's only initialized once without any
        race conditions among threads */
-    static std::map<std::string, AbstractManager::Plugin*>*&(*const uniqueGlobals)() = reinterpret_cast<std::map<std::string, AbstractManager::Plugin*>*&(*)()>(Utility::Implementation::windowsWeakSymbol("corradePluginManagerUniqueGlobalPlugins"));
+    static std::map<std::string, AbstractManager::Plugin*>*&(*const uniqueGlobals)() = reinterpret_cast<std::map<std::string, AbstractManager::Plugin*>*&(*)()>(Utility::Implementation::windowsWeakSymbol("corradePluginManagerUniqueGlobalPlugins", reinterpret_cast<void*>(&corradePluginManagerUniqueGlobalPlugins)));
     return uniqueGlobals();
 }
 

diff --git a/src/Corrade/Utility/Debug.cpp b/src/Corrade/Utility/Debug.cpp
@@ -141,7 +141,7 @@ namespace {
 DebugGlobals& windowsDebugGlobals() {
     /* A function-local static to ensure it's only initialized once without any
        race conditions among threads */
-    static DebugGlobals&(*const uniqueGlobals)() = reinterpret_cast<DebugGlobals&(*)()>(Implementation::windowsWeakSymbol("corradeUtilityUniqueDebugGlobals"));
+    static DebugGlobals&(*const uniqueGlobals)() = reinterpret_cast<DebugGlobals&(*)()>(Implementation::windowsWeakSymbol("corradeUtilityUniqueDebugGlobals", reinterpret_cast<void*>(&corradeUtilityUniqueDebugGlobals)));
     return uniqueGlobals();
 }
 

diff --git a/src/Corrade/Utility/Implementation/WindowsWeakSymbol.cpp b/src/Corrade/Utility/Implementation/WindowsWeakSymbol.cpp
@@ -25,18 +25,23 @@
 
 #include "WindowsWeakSymbol.h"
 
-#include "Corrade/Utility/Assert.h"
+#include <cstdio>
 
 #define WIN32_LEAN_AND_MEAN 1
 #define VC_EXTRALEAN
 #include <windows.h>
 
 namespace Corrade { namespace Utility { namespace Implementation {
 
-void* windowsWeakSymbol(const char* name) {
+void* windowsWeakSymbol(const char* name, void* backup) {
     /* FARPROC?! I want either a function pointer or a variable pointer */
     void* address = reinterpret_cast<void*>(GetProcAddress(GetModuleHandleA(nullptr), name));
-    CORRADE_INTERNAL_ASSERT(address);
+    /* This shouldn't fail, except in Python, where it's a sad, sad misery. */
+    if(!address) {
+        std::fprintf(stderr, "Cannot query global symbol %s and make it unique\n"
+            "across DLLs. App may misbehave, sorry. Build Corrade as dynamic as a workaround.\n", name);
+        address = backup;
+    }
     return address;
 }
 

diff --git a/src/Corrade/Utility/Implementation/WindowsWeakSymbol.h b/src/Corrade/Utility/Implementation/WindowsWeakSymbol.h
@@ -33,7 +33,7 @@
 
 namespace Corrade { namespace Utility { namespace Implementation {
 
-void* windowsWeakSymbol(const char* name);
+void* windowsWeakSymbol(const char* name, void* backup);
 
 }}}
 

diff --git a/src/Corrade/Utility/Resource.cpp b/src/Corrade/Utility/Resource.cpp
@@ -104,7 +104,7 @@ namespace {
 ResourceGlobals& windowsResourceGlobals() {
     /* A function-local static to ensure it's only initialized once without any
        race conditions among threads */
-    static ResourceGlobals* const uniqueGlobals = reinterpret_cast<ResourceGlobals*>(Implementation::windowsWeakSymbol("corradeUtilityUniqueWindowsResourceGlobals"));
+    static ResourceGlobals* uniqueGlobals = reinterpret_cast<ResourceGlobals*>(Implementation::windowsWeakSymbol("corradeUtilityUniqueWindowsResourceGlobals", &corradeUtilityUniqueWindowsResourceGlobals));
     return *uniqueGlobals;
 }