Add a sprinkle of speculative anti-crash dust

Bugs: way too many
Bug: 113367810
Test: well it builds...
Change-Id: If00bcaad1c535c4996b59c1b5a7d3a4bba849191

1 files changed, 54 insertions, 0 deletions

diff --git a/libs/hwui/utils/Result.h b/libs/hwui/utils/Result.h
new file mode 100644
index 000000000000..7f33f2e3424d
--- /dev/null
+++ b/libs/hwui/utils/Result.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <variant>
+#include <log/log.h>
+
+namespace android::uirenderer {
+
+template <typename E>
+struct Error {
+    E error;
+};
+
+template <typename R, typename E>
+class Result {
+public:
+    Result(const R& r) : result(std::forward<R>(r)) {}
+    Result(R&& r) : result(std::forward<R>(r)) {}
+    Result(Error<E>&& error) : result(std::forward<Error<E>>(error)) {}
+
+    operator bool() const {
+        return result.index() == 0;
+    }
+
+    R unwrap() const {
+        LOG_ALWAYS_FATAL_IF(result.index() == 1, "unwrap called on error value!");
+        return std::get<R>(result);
+    }
+
+    E error() const {
+        LOG_ALWAYS_FATAL_IF(result.index() == 0, "No error to get from Result");
+        return std::get<Error<E>>(result).error;
+    }
+
+private:
+    std::variant<R, Error<E>> result;
+};
+
+}; // namespace android::uirenderer