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().

visualtest/src/variator_random.c

@@ -0,0 +1,111 @@
+/* See COPYING.txt for the full license governing this code. */
+/**
+ * \file variator_random.c
+ *
+ * Source file for the variator that tests the SUT with random variations to the
+ * input parameters.
+ */
+
+#include <time.h>
+#include <SDL_test.h>
+#include "SDL_visualtest_random_variator.h"
+
+int
+SDLVisualTest_InitRandomVariator(SDLVisualTest_RandomVariator* variator,
+                                 SDLVisualTest_SUTConfig* config, Uint64 seed)
+{
+    if(!variator)
+    {
+        SDLTest_LogError("variator argument cannot be NULL");
+        return 0;
+    }
+    if(!config)
+    {
+        SDLTest_LogError("config argument cannot be NULL");
+        return 0;
+    }
+
+    if(seed)
+        SDLTest_FuzzerInit(seed);
+    else
+        SDLTest_FuzzerInit(time(NULL));
+
+    variator->config = *config;
+
+    if(!SDLVisualTest_InitVariation(&variator->variation, &variator->config))
+    {
+        SDLTest_LogError("SDLVisualTest_InitVariation() failed");
+        return 0;
+    }
+
+    return 1;
+}
+
+char*
+SDLVisualTest_GetNextRandomVariation(SDLVisualTest_RandomVariator* variator)
+{
+    SDLVisualTest_SUTOptionValue* vars;
+    SDLVisualTest_SUTOption* options;
+    int i;
+    if(!variator)
+    {
+        SDLTest_LogError("variator argument cannot be NULL");
+        return NULL;
+    }
+ 
+    /* to save typing */
+    vars = variator->variation.vars;
+    options = variator->config.options;
+
+    /* generate a random variation */
+    for(i = 0; i < variator->variation.num_vars; i++)
+    {
+        switch(options[i].type)
+        {
+            case SDL_SUT_OPTIONTYPE_BOOL:
+                vars[i].bool_value = SDLTest_RandomIntegerInRange(0, 1) ? SDL_FALSE :
+                                                                          SDL_TRUE;
+            break;
+
+            case SDL_SUT_OPTIONTYPE_ENUM:
+            {
+                int emx = 0;
+                while(options[i].data.enum_values[emx])
+                    emx++;
+                vars[i].enumerated.index = SDLTest_RandomIntegerInRange(0, emx - 1);
+            }
+            break;
+            
+            case SDL_SUT_OPTIONTYPE_INT:
+                vars[i].integer.value = SDLTest_RandomIntegerInRange(
+                                        options[i].data.range.min,
+                                        options[i].data.range.max);
+            break;
+
+            case SDL_SUT_OPTIONTYPE_STRING:
+                // String values are left unchanged
+            break;
+        }
+    }
+
+    /* convert variation to an arguments string */
+    if(!SDLVisualTest_MakeStrFromVariation(&variator->variation, &variator->config,
+                                           variator->buffer, MAX_SUT_ARGS_LEN))
+    {
+        SDLTest_LogError("SDLVisualTest_MakeStrFromVariation() failed");
+        return NULL;
+    }
+
+    return variator->buffer;
+}
+
+void SDLVisualTest_FreeRandomVariator(SDLVisualTest_RandomVariator* variator)
+{
+    if(!variator)
+    {
+        SDLTest_LogError("variator argument cannot be NULL");
+        return;
+    }
+    SDL_free(variator->variation.vars);
+    variator->variation.vars = NULL;
+}