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Diffstat (limited to 'src/leveldb/include/leveldb/status.h')
-rw-r--r-- | src/leveldb/include/leveldb/status.h | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/src/leveldb/include/leveldb/status.h b/src/leveldb/include/leveldb/status.h new file mode 100644 index 0000000000..11dbd4b47e --- /dev/null +++ b/src/leveldb/include/leveldb/status.h @@ -0,0 +1,106 @@ +// 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_ |