first draft of error checking / reporting API

tests/ErrorTest.cpp

+
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#include "Test.h"
+#include "SkError.h"
+#include "SkPath.h"
+#include "SkRect.h"
+
+#define CHECK(errcode)                                                        \
+  REPORTER_ASSERT( reporter, (err = SkGetLastError()) == errcode);            \
+  if (err != kNoError_SkError)                                                \
+  {                                                                           \
+     SkDebugf("Last error string: %s\n", SkGetLastErrorString());             \
+     SkClearLastError();                                                      \
+  }
+                       
+void cb(SkError err, void *context) {
+    int *context_ptr = static_cast<int *>(context);
+    SkDebugf("CB (0x%x): %s\n", *context_ptr, SkGetLastErrorString());
+}
+
+static void ErrorTest(skiatest::Reporter* reporter) {
+    SkError err;
+    
+    CHECK(kNoError_SkError);
+    
+    SkRect r = SkRect::MakeWH(50, 100);
+    CHECK(kNoError_SkError);
+
+    SkPath path;
+    path.addRect(r);
+    CHECK(kNoError_SkError);
+    
+    path.addRoundRect(r, 10, 10);
+    CHECK(kNoError_SkError);
+
+    // should trigger the default error callback, which just prints to the screen.
+    path.addRoundRect(r, -10, -10);
+    CHECK(kInvalidArgument_SkError);
+    CHECK(kNoError_SkError);
+
+    int test_value = 0xdeadbeef;
+    SkSetErrorCallback(cb, &test_value);
+
+    // should trigger *our* callback.
+    path.addRoundRect(r, -10, -10);
+    CHECK(kInvalidArgument_SkError);
+    CHECK(kNoError_SkError);
+
+    // Should trigger the default one again.
+    SkSetErrorCallback(NULL, NULL);
+    path.addRoundRect(r, -10, -10);
+    CHECK(kInvalidArgument_SkError);
+    CHECK(kNoError_SkError);
+}
+
+#include "TestClassDef.h"
+DEFINE_TESTCLASS("Error", ErrorTestClass, ErrorTest)