| // Copyright (c) 2011 The LevelDB Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. See the AUTHORS file for names of contributors. |
| // |
| // A Status encapsulates the result of an operation. It may indicate success, |
| // or it may indicate an error with an associated error message. |
| // |
| // Multiple threads can invoke const methods on a Status without |
| // external synchronization, but if any of the threads may call a |
| // non-const method, all threads accessing the same Status must use |
| // external synchronization. |
| |
| #ifndef STORAGE_LEVELDB_INCLUDE_STATUS_H_ |
| #define STORAGE_LEVELDB_INCLUDE_STATUS_H_ |
| |
| #include <string> |
| #include "leveldb/slice.h" |
| |
| namespace leveldb { |
| |
| class Status { |
| public: |
| // Create a success status. |
| Status() : state_(NULL) { } |
| ~Status() { delete[] state_; } |
| |
| // Copy the specified status. |
| Status(const Status& s); |
| void operator=(const Status& s); |
| |
| // Return a success status. |
| static Status OK() { return Status(); } |
| |
| // Return error status of an appropriate type. |
| static Status NotFound(const Slice& msg, const Slice& msg2 = Slice()) { |
| return Status(kNotFound, msg, msg2); |
| } |
| static Status Corruption(const Slice& msg, const Slice& msg2 = Slice()) { |
| return Status(kCorruption, msg, msg2); |
| } |
| static Status NotSupported(const Slice& msg, const Slice& msg2 = Slice()) { |
| return Status(kNotSupported, msg, msg2); |
| } |
| static Status InvalidArgument(const Slice& msg, const Slice& msg2 = Slice()) { |
| return Status(kInvalidArgument, msg, msg2); |
| } |
| static Status IOError(const Slice& msg, const Slice& msg2 = Slice()) { |
| return Status(kIOError, msg, msg2); |
| } |
| |
| // Returns true iff the status indicates success. |
| bool ok() const { return (state_ == NULL); } |
| |
| // Returns true iff the status indicates a NotFound error. |
| bool IsNotFound() const { return code() == kNotFound; } |
| |
| // Returns true iff the status indicates a Corruption error. |
| bool IsCorruption() const { return code() == kCorruption; } |
| |
| // Returns true iff the status indicates an IOError. |
| bool IsIOError() const { return code() == kIOError; } |
| |
| // Return a string representation of this status suitable for printing. |
| // Returns the string "OK" for success. |
| std::string ToString() const; |
| |
| private: |
| // OK status has a NULL state_. Otherwise, state_ is a new[] array |
| // of the following form: |
| // state_[0..3] == length of message |
| // state_[4] == code |
| // state_[5..] == message |
| const char* state_; |
| |
| enum Code { |
| kOk = 0, |
| kNotFound = 1, |
| kCorruption = 2, |
| kNotSupported = 3, |
| kInvalidArgument = 4, |
| kIOError = 5 |
| }; |
| |
| Code code() const { |
| return (state_ == NULL) ? kOk : static_cast<Code>(state_[4]); |
| } |
| |
| Status(Code code, const Slice& msg, const Slice& msg2); |
| static const char* CopyState(const char* s); |
| }; |
| |
| inline Status::Status(const Status& s) { |
| state_ = (s.state_ == NULL) ? NULL : CopyState(s.state_); |
| } |
| inline void Status::operator=(const Status& s) { |
| // The following condition catches both aliasing (when this == &s), |
| // and the common case where both s and *this are ok. |
| if (state_ != s.state_) { |
| delete[] state_; |
| state_ = (s.state_ == NULL) ? NULL : CopyState(s.state_); |
| } |
| } |
| |
| } // namespace leveldb |
| |
| #endif // STORAGE_LEVELDB_INCLUDE_STATUS_H_ |