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/video/emscripten/SDL_emscriptenmouse.c

@@ -0,0 +1,232 @@
+/*
+  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"
+
+#if SDL_VIDEO_DRIVER_EMSCRIPTEN
+
+#include <emscripten/emscripten.h>
+#include <emscripten/html5.h>
+
+#include "SDL_emscriptenmouse.h"
+
+#include "../../events/SDL_mouse_c.h"
+#include "SDL_assert.h"
+
+
+static SDL_Cursor*
+Emscripten_CreateDefaultCursor()
+{
+    SDL_Cursor* cursor;
+    Emscripten_CursorData *curdata;
+
+    cursor = SDL_calloc(1, sizeof(SDL_Cursor));
+    if (cursor) {
+        curdata = (Emscripten_CursorData *) SDL_calloc(1, sizeof(*curdata));
+        if (!curdata) {
+            SDL_OutOfMemory();
+            SDL_free(cursor);
+            return NULL;
+        }
+
+        curdata->system_cursor = "default";
+        cursor->driverdata = curdata;
+    }
+    else {
+        SDL_OutOfMemory();
+    }
+
+    return cursor;
+}
+
+static SDL_Cursor*
+Emscripten_CreateCursor(SDL_Surface* sruface, int hot_x, int hot_y)
+{
+    return Emscripten_CreateDefaultCursor();
+}
+
+static SDL_Cursor*
+Emscripten_CreateSystemCursor(SDL_SystemCursor id)
+{
+    SDL_Cursor *cursor;
+    Emscripten_CursorData *curdata;
+    const char *cursor_name = NULL;
+
+    switch(id) {
+        case SDL_SYSTEM_CURSOR_ARROW:
+            cursor_name = "default";
+            break;
+        case SDL_SYSTEM_CURSOR_IBEAM:
+            cursor_name = "text";
+            break;
+        case SDL_SYSTEM_CURSOR_WAIT:
+            cursor_name = "wait";
+            break;
+        case SDL_SYSTEM_CURSOR_CROSSHAIR:
+            cursor_name = "crosshair";
+            break;
+        case SDL_SYSTEM_CURSOR_WAITARROW:
+            cursor_name = "progress";
+            break;
+        case SDL_SYSTEM_CURSOR_SIZENWSE:
+            cursor_name = "nwse-resize";
+            break;
+        case SDL_SYSTEM_CURSOR_SIZENESW:
+            cursor_name = "nesw-resize";
+            break;
+        case SDL_SYSTEM_CURSOR_SIZEWE:
+            cursor_name = "ew-resize";
+            break;
+        case SDL_SYSTEM_CURSOR_SIZENS:
+            cursor_name = "ns-resize";
+            break;
+        case SDL_SYSTEM_CURSOR_SIZEALL:
+            break;
+        case SDL_SYSTEM_CURSOR_NO:
+            cursor_name = "not-allowed";
+            break;
+        case SDL_SYSTEM_CURSOR_HAND:
+            cursor_name = "pointer";
+            break;
+        default:
+            SDL_assert(0);
+            return NULL;
+    }
+
+    cursor = (SDL_Cursor *) SDL_calloc(1, sizeof(*cursor));
+    if (!cursor) {
+        SDL_OutOfMemory();
+        return NULL;
+    }
+    curdata = (Emscripten_CursorData *) SDL_calloc(1, sizeof(*curdata));
+    if (!curdata) {
+        SDL_OutOfMemory();
+        SDL_free(cursor);
+        return NULL;
+    }
+
+    curdata->system_cursor = cursor_name;
+    cursor->driverdata = curdata;
+
+    return cursor;
+}
+
+static void
+Emscripten_FreeCursor(SDL_Cursor* cursor)
+{
+    Emscripten_CursorData *curdata;
+    if (cursor) {
+        curdata = (Emscripten_CursorData *) cursor->driverdata;
+
+        if (curdata != NULL) {
+            SDL_free(cursor->driverdata);
+        }
+
+        SDL_free(cursor);
+    }
+}
+
+static int
+Emscripten_ShowCursor(SDL_Cursor* cursor)
+{
+    Emscripten_CursorData *curdata;
+    if (SDL_GetMouseFocus() != NULL) {
+        if(cursor && cursor->driverdata) {
+            curdata = (Emscripten_CursorData *) cursor->driverdata;
+
+            if(curdata->system_cursor) {
+                EM_ASM_INT({
+                    if (Module['canvas']) {
+                        Module['canvas'].style['cursor'] = Module['Pointer_stringify']($0);
+                    }
+                    return 0;
+                }, curdata->system_cursor);
+            }
+        }
+        else {
+            EM_ASM(
+                if (Module['canvas']) {
+                    Module['canvas'].style['cursor'] = 'none';
+                }
+            );
+        }
+    }
+    return 0;
+}
+
+static void
+Emscripten_WarpMouse(SDL_Window* window, int x, int y)
+{
+    SDL_Unsupported();
+}
+
+static int
+Emscripten_SetRelativeMouseMode(SDL_bool enabled)
+{
+    /* TODO: pointer lock isn't actually enabled yet */
+    if(enabled) {
+        if(emscripten_request_pointerlock(NULL, 1) >= EMSCRIPTEN_RESULT_SUCCESS) {
+            return 0;
+        }
+    } else {
+        if(emscripten_exit_pointerlock() >= EMSCRIPTEN_RESULT_SUCCESS) {
+            return 0;
+        }
+    }
+    return -1;
+}
+
+void
+Emscripten_InitMouse()
+{
+    SDL_Mouse* mouse = SDL_GetMouse();
+
+    mouse->CreateCursor         = Emscripten_CreateCursor;
+    mouse->ShowCursor           = Emscripten_ShowCursor;
+    mouse->FreeCursor           = Emscripten_FreeCursor;
+    mouse->WarpMouse            = Emscripten_WarpMouse;
+    mouse->CreateSystemCursor   = Emscripten_CreateSystemCursor;
+    mouse->SetRelativeMouseMode = Emscripten_SetRelativeMouseMode;
+
+    SDL_SetDefaultCursor(Emscripten_CreateDefaultCursor());
+}
+
+void
+Emscripten_FiniMouse()
+{
+    SDL_Mouse* mouse = SDL_GetMouse();
+
+    Emscripten_FreeCursor(mouse->def_cursor);
+    mouse->def_cursor = NULL;
+
+    mouse->CreateCursor         = NULL;
+    mouse->ShowCursor           = NULL;
+    mouse->FreeCursor           = NULL;
+    mouse->WarpMouse            = NULL;
+    mouse->CreateSystemCursor   = NULL;
+    mouse->SetRelativeMouseMode = NULL;
+}
+
+#endif /* SDL_VIDEO_DRIVER_EMSCRIPTEN */
+
+/* vi: set ts=4 sw=4 expandtab: */
+