Fixed crash if initialization of EGL failed but was tried again later.

The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly
uninitialized data structure if loading the library first failed. A later try to
use EGL then skipped initialization and assumed it was previously successful
because the data structure now already existed. This led to at least one crash
in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was
dereferenced to make a call to eglBindAPI().

src/filesystem/windows/SDL_sysfilesystem.c

@@ -0,0 +1,182 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2015 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "../../SDL_internal.h"
+
+#ifdef SDL_FILESYSTEM_WINDOWS
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+/* System dependent filesystem routines                                */
+
+#include "../../core/windows/SDL_windows.h"
+#include <shlobj.h>
+
+#include "SDL_assert.h"
+#include "SDL_error.h"
+#include "SDL_stdinc.h"
+#include "SDL_filesystem.h"
+
+char *
+SDL_GetBasePath(void)
+{
+    typedef DWORD (WINAPI *GetModuleFileNameExW_t)(HANDLE, HMODULE, LPWSTR, DWORD);
+    GetModuleFileNameExW_t pGetModuleFileNameExW;
+    DWORD buflen = 128;
+    WCHAR *path = NULL;
+    HANDLE psapi = LoadLibrary(L"psapi.dll");
+    char *retval = NULL;
+    DWORD len = 0;
+    int i;
+
+    if (!psapi) {
+        WIN_SetError("Couldn't load psapi.dll");
+        return NULL;
+    }
+
+    pGetModuleFileNameExW = (GetModuleFileNameExW_t)GetProcAddress(psapi, "GetModuleFileNameExW");
+    if (!pGetModuleFileNameExW) {
+        WIN_SetError("Couldn't find GetModuleFileNameExW");
+        FreeLibrary(psapi);
+        return NULL;
+    }
+
+    while (SDL_TRUE) {
+        void *ptr = SDL_realloc(path, buflen * sizeof (WCHAR));
+        if (!ptr) {
+            SDL_free(path);
+            FreeLibrary(psapi);
+            SDL_OutOfMemory();
+            return NULL;
+        }
+
+        path = (WCHAR *) ptr;
+
+        len = pGetModuleFileNameExW(GetCurrentProcess(), NULL, path, buflen);
+        if (len != buflen) {
+            break;
+        }
+
+        /* buffer too small? Try again. */
+        buflen *= 2;
+    }
+
+    FreeLibrary(psapi);
+
+    if (len == 0) {
+        SDL_free(path);
+        WIN_SetError("Couldn't locate our .exe");
+        return NULL;
+    }
+
+    for (i = len-1; i > 0; i--) {
+        if (path[i] == '\\') {
+            break;
+        }
+    }
+
+    SDL_assert(i > 0); /* Should have been an absolute path. */
+    path[i+1] = '\0';  /* chop off filename. */
+
+    retval = WIN_StringToUTF8(path);
+    SDL_free(path);
+
+    return retval;
+}
+
+char *
+SDL_GetPrefPath(const char *org, const char *app)
+{
+    /*
+     * Vista and later has a new API for this, but SHGetFolderPath works there,
+     *  and apparently just wraps the new API. This is the new way to do it:
+     *
+     *     SHGetKnownFolderPath(FOLDERID_RoamingAppData, KF_FLAG_CREATE,
+     *                          NULL, &wszPath);
+     */
+
+    WCHAR path[MAX_PATH];
+    char *retval = NULL;
+    WCHAR* worg = NULL;
+    WCHAR* wapp = NULL;
+    size_t new_wpath_len = 0;
+    BOOL api_result = FALSE;
+
+    if (!SUCCEEDED(SHGetFolderPathW(NULL, CSIDL_APPDATA | CSIDL_FLAG_CREATE, NULL, 0, path))) {
+        WIN_SetError("Couldn't locate our prefpath");
+        return NULL;
+    }
+
+    worg = WIN_UTF8ToString(org);
+    if (worg == NULL) {
+        SDL_OutOfMemory();
+        return NULL;
+    }
+
+    wapp = WIN_UTF8ToString(app);
+    if (wapp == NULL) {
+        SDL_free(worg);
+        SDL_OutOfMemory();
+        return NULL;
+    }
+
+    new_wpath_len = lstrlenW(worg) + lstrlenW(wapp) + lstrlenW(path) + 3;
+
+    if ((new_wpath_len + 1) > MAX_PATH) {
+        SDL_free(worg);
+        SDL_free(wapp);
+        WIN_SetError("Path too long.");
+        return NULL;
+    }
+
+    lstrcatW(path, L"\\");
+    lstrcatW(path, worg);
+    SDL_free(worg);
+
+    api_result = CreateDirectoryW(path, NULL);
+    if (api_result == FALSE) {
+        if (GetLastError() != ERROR_ALREADY_EXISTS) {
+            SDL_free(wapp);
+            WIN_SetError("Couldn't create a prefpath.");
+            return NULL;
+        }
+    }
+
+    lstrcatW(path, L"\\");
+    lstrcatW(path, wapp);
+    SDL_free(wapp);
+
+    api_result = CreateDirectoryW(path, NULL);
+    if (api_result == FALSE) {
+        if (GetLastError() != ERROR_ALREADY_EXISTS) {
+            WIN_SetError("Couldn't create a prefpath.");
+            return NULL;
+        }
+    }
+
+    lstrcatW(path, L"\\");
+
+    retval = WIN_StringToUTF8(path);
+
+    return retval;
+}
+
+#endif /* SDL_FILESYSTEM_WINDOWS */
+
+/* vi: set ts=4 sw=4 expandtab: */