Simplify Vulkan extension checks

Related to #478.

src/cocoa_window.m

@@ -1618,10 +1618,8 @@ const char* _glfwPlatformGetClipboardString(_GLFWwindow* window)
     return _glfw.ns.clipboardString;
 }
 
-char** _glfwPlatformGetRequiredInstanceExtensions(uint32_t* count)
+void _glfwPlatformGetRequiredInstanceExtensions(char** extensions)
 {
-    *count = 0;
-    return NULL;
 }
 
 int _glfwPlatformGetPhysicalDevicePresentationSupport(VkInstance instance,

src/internal.h

@@ -449,8 +449,7 @@ struct _GLFWlibrary
     struct {
         GLFWbool        available;
         void*           handle;
-        char**          extensions;
-        uint32_t        extensionCount;
+        char*           extensions[2];
 #if !defined(_GLFW_VULKAN_STATIC)
         PFN_vkEnumerateInstanceExtensionProperties EnumerateInstanceExtensionProperties;
         PFN_vkGetInstanceProcAddr GetInstanceProcAddr;
@@ -792,7 +791,7 @@ void _glfwPlatformSetCursor(_GLFWwindow* window, _GLFWcursor* cursor);
 
 /*! @ingroup platform
  */
-char** _glfwPlatformGetRequiredInstanceExtensions(uint32_t* count);
+void _glfwPlatformGetRequiredInstanceExtensions(char** extensions);
 
 /*! @ingroup platform
  */

src/mir_window.c

@@ -758,21 +758,13 @@ const char* _glfwPlatformGetClipboardString(_GLFWwindow* window)
     return NULL;
 }
 
-char** _glfwPlatformGetRequiredInstanceExtensions(uint32_t* count)
+void _glfwPlatformGetRequiredInstanceExtensions(char** extensions)
 {
-    char** extensions;
+    if (!_glfw.vk.KHR_surface || !_glfw.vk.KHR_mir_surface)
+        return;
 
-    *count = 0;
-
-    if (!_glfw.vk.KHR_mir_surface)
-        return NULL;
-
-    extensions = calloc(2, sizeof(char*));
-    extensions[0] = strdup("VK_KHR_surface");
-    extensions[1] = strdup("VK_KHR_mir_surface");
-
-    *count = 2;
-    return extensions;
+    extensions[0] = "VK_KHR_surface";
+    extensions[1] = "VK_KHR_mir_surface";
 }
 
 int _glfwPlatformGetPhysicalDevicePresentationSupport(VkInstance instance,

src/vulkan.c

@@ -124,23 +124,13 @@ GLFWbool _glfwInitVulkan(void)
 
     _glfw.vk.available = GLFW_TRUE;
 
-    if (_glfw.vk.KHR_surface)
-    {
-        _glfw.vk.extensions =
-            _glfwPlatformGetRequiredInstanceExtensions(&_glfw.vk.extensionCount);
-    }
+    _glfwPlatformGetRequiredInstanceExtensions(_glfw.vk.extensions);
 
     return GLFW_TRUE;
 }
 
 void _glfwTerminateVulkan(void)
 {
-    uint32_t i;
-
-    for (i = 0;  i < _glfw.vk.extensionCount;  i++)
-        free(_glfw.vk.extensions[i]);
-    free(_glfw.vk.extensions);
-
     if (_glfw.vk.handle)
         _glfw_dlclose(_glfw.vk.handle);
 }
@@ -223,7 +213,7 @@ GLFWAPI const char** glfwGetRequiredInstanceExtensions(uint32_t* count)
         return NULL;
     }
 
-    *count = _glfw.vk.extensionCount;
+    *count = 2;
     return (const char**) _glfw.vk.extensions;
 }
 

src/win32_window.c

@@ -1642,21 +1642,13 @@ const char* _glfwPlatformGetClipboardString(_GLFWwindow* window)
     return _glfw.win32.clipboardString;
 }
 
-char** _glfwPlatformGetRequiredInstanceExtensions(uint32_t* count)
+void _glfwPlatformGetRequiredInstanceExtensions(char** extensions)
 {
-    char** extensions;
-
-    *count = 0;
-
-    if (!_glfw.vk.KHR_win32_surface)
-        return NULL;
-
-    extensions = calloc(2, sizeof(char*));
-    extensions[0] = strdup("VK_KHR_surface");
-    extensions[1] = strdup("VK_KHR_win32_surface");
+    if (!_glfw.vk.KHR_surface || !_glfw.vk.KHR_win32_surface)
+        return;
 
-    *count = 2;
-    return extensions;
+    extensions[0] = "VK_KHR_surface";
+    extensions[1] = "VK_KHR_win32_surface";
 }
 
 int _glfwPlatformGetPhysicalDevicePresentationSupport(VkInstance instance,

src/wl_window.c

@@ -960,21 +960,13 @@ const char* _glfwPlatformGetClipboardString(_GLFWwindow* window)
     return NULL;
 }
 
-char** _glfwPlatformGetRequiredInstanceExtensions(uint32_t* count)
+void _glfwPlatformGetRequiredInstanceExtensions(char** extensions)
 {
-    char** extensions;
-
-    *count = 0;
-
-    if (!_glfw.vk.KHR_wayland_surface)
-        return NULL;
-
-    extensions = calloc(2, sizeof(char*));
-    extensions[0] = strdup("VK_KHR_surface");
-    extensions[1] = strdup("VK_KHR_wayland_surface");
+    if (!_glfw.vk.KHR_surface || !_glfw.vk.KHR_wayland_surface)
+        return;
 
-    *count = 2;
-    return extensions;
+    extensions[0] = "VK_KHR_surface";
+    extensions[1] = "VK_KHR_wayland_surface";
 }
 
 int _glfwPlatformGetPhysicalDevicePresentationSupport(VkInstance instance,

src/x11_window.c

@@ -2303,28 +2303,23 @@ const char* _glfwPlatformGetClipboardString(_GLFWwindow* window)
     return _glfw.x11.clipboardString;
 }
 
-char** _glfwPlatformGetRequiredInstanceExtensions(uint32_t* count)
+void _glfwPlatformGetRequiredInstanceExtensions(char** extensions)
 {
-    char** extensions;
-
-    *count = 0;
+    if (!_glfw.vk.KHR_surface)
+        return;
 
     if (!_glfw.vk.KHR_xcb_surface || !_glfw.x11.x11xcb.handle)
     {
         if (!_glfw.vk.KHR_xlib_surface)
-            return NULL;
+            return;
     }
 
-    extensions = calloc(2, sizeof(char*));
-    extensions[0] = strdup("VK_KHR_surface");
+    extensions[0] = "VK_KHR_surface";
 
     if (_glfw.vk.KHR_xcb_surface && _glfw.x11.x11xcb.handle)
-        extensions[1] = strdup("VK_KHR_xcb_surface");
+        extensions[1] = "VK_KHR_xcb_surface";
     else
-        extensions[1] = strdup("VK_KHR_xlib_surface");
-
-    *count = 2;
-    return extensions;
+        extensions[1] = "VK_KHR_xlib_surface";
 }
 
 int _glfwPlatformGetPhysicalDevicePresentationSupport(VkInstance instance,