upload android base code part3

android/art/cmdline/cmdline_result.h

@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#ifndef ART_CMDLINE_CMDLINE_RESULT_H_
+#define ART_CMDLINE_CMDLINE_RESULT_H_
+
+#include <assert.h>
+#include <utils.h>
+
+namespace art {
+  // Result of an attempt to process the command line arguments. If fails, specifies
+  // the specific error code and an error message.
+  // Use the value-carrying CmdlineParseResult<T> to get an additional value out in a success case.
+  struct CmdlineResult {
+    enum Status {
+      kSuccess,
+      // Error codes:
+      kUsage,
+      kFailure,
+      kOutOfRange,
+      kUnknown,
+    };
+
+    // Short-hand for checking if the result was successful.
+    operator bool() const {
+      return IsSuccess();
+    }
+
+    // Check if the operation has succeeded.
+    bool IsSuccess() const { return status_ == kSuccess; }
+    // Check if the operation was not a success.
+    bool IsError() const { return status_ != kSuccess; }
+    // Get the specific status, regardless of whether it's failure or success.
+    Status GetStatus() const { return status_; }
+
+    // Get the error message, *must* only be called for error status results.
+    const std::string& GetMessage() const { assert(IsError()); return message_; }
+
+    // Constructor any status. No message.
+    explicit CmdlineResult(Status status) : status_(status) {}
+
+    // Constructor with an error status, copying the message.
+    CmdlineResult(Status status, const std::string& message)
+      : status_(status), message_(message) {
+      assert(status != kSuccess);
+    }
+
+    // Constructor with an error status, taking over the message.
+    CmdlineResult(Status status, std::string&& message)
+      : status_(status), message_(message) {
+      assert(status != kSuccess);
+    }
+
+    // Make sure copying exists
+    CmdlineResult(const CmdlineResult&) = default;
+    // Make sure moving is cheap
+    CmdlineResult(CmdlineResult&&) = default;
+
+  private:
+    const Status status_;
+    const std::string message_;
+  };
+
+  // TODO: code-generate this
+  static inline std::ostream& operator<<(std::ostream& stream, CmdlineResult::Status status) {
+    switch (status) {
+      case CmdlineResult::kSuccess:
+        stream << "kSuccess";
+        break;
+      case CmdlineResult::kUsage:
+        stream << "kUsage";
+        break;
+      case CmdlineResult::kFailure:
+        stream << "kFailure";
+        break;
+      case CmdlineResult::kOutOfRange:
+        stream << "kOutOfRange";
+        break;
+      case CmdlineResult::kUnknown:
+        stream << "kUnknown";
+        break;
+      default:
+        UNREACHABLE();
+    }
+    return stream;
+  }
+
+}  // namespace art
+
+#endif  // ART_CMDLINE_CMDLINE_RESULT_H_