| /* |
| * Copyright 2012, 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 BCC_EXECUTION_ENGINE_FILE_BASE_H |
| #define BCC_EXECUTION_ENGINE_FILE_BASE_H |
| |
| #include <fcntl.h> |
| |
| #include <string> |
| |
| #include <llvm/Support/system_error.h> |
| |
| namespace android { |
| class FileMap; |
| } |
| |
| namespace bcc { |
| |
| class FileBase { |
| public: |
| enum OpenModeEnum { |
| kReadMode = 1 << 0, |
| kWriteMode = 1 << 1, |
| kReadWriteMode = (kReadMode | kWriteMode), |
| }; |
| |
| enum FlagEnum { |
| // The openning file is a binary file. |
| kBinary = 1 << 0, |
| }; |
| |
| enum LockModeEnum { |
| // The shared resource behind the Stream locked in ReadLock mode can be |
| // locked by other processes at the same time. |
| kReadLock, |
| |
| // The shared resource behind the Stream locked in WriteLock mode can only |
| // be locked by one process. It's exclusive. That is, the shared resource |
| // cannot have both ReadLock and WriteLock simultaneously. |
| kWriteLock |
| }; |
| |
| // Default configuration to the lock(). |
| enum { |
| kDefaultMaxRetryLock = 4, |
| kDefaultRetryLockInterval = 200000UL, |
| }; |
| |
| protected: |
| // Grant direct access of the internal file descriptor to the sub-class and |
| // error message such that they can implement their own I/O functionality. |
| int mFD; |
| |
| llvm::error_code mError; |
| |
| private: |
| std::string mName; |
| |
| // The 2nd argument to the POSIX open(). |
| unsigned mOpenFlags; |
| |
| // True true if we should call unlock() in destructor. |
| bool mShouldUnlock; |
| |
| // Open mName with flag mOpenFlags (using POSIX open().) |
| bool open(); |
| |
| // Return true if mFD is the corresponded file descriptor to the file named |
| // mName on the filesystem. This check may returns failed, for example, |
| // someone re-create the file with the same name after we openning the file. |
| bool checkFileIntegrity(); |
| |
| inline bool reopen() { |
| // Don't need to check the object state since this is a private method. |
| close(); |
| return open(); |
| } |
| |
| private: |
| FileBase(FileBase &); // Do not implement. |
| void operator=(const FileBase &); // Do not implement. |
| |
| protected: |
| // pOpenFlags is the 2nd argument to the POSIX open(). pFlags are the flags to |
| // FileBase. It's a bit set composed by the value defined in |
| // FileBase::FlagEnum. |
| FileBase(const std::string &pFilename, unsigned pOpenFlags, unsigned pFlags); |
| |
| void detectError(); |
| |
| public: |
| // Lock the file descriptor in given pMode. If pNonblocking is true, the lock |
| // request issued will return immediately when the shared resource is locked. |
| // In this case, it retries pMaxRetry times, each wait pRetryInterval (in |
| // usecs) before the previous retry getting done. |
| // |
| // Only file is allowed to use this API. |
| bool lock(enum LockModeEnum pMode, bool pNonblocking = true, |
| unsigned pMaxRetry = kDefaultMaxRetryLock, |
| useconds_t pRetryInterval = kDefaultRetryLockInterval); |
| |
| void unlock(); |
| |
| // Map the file content to the memory. |
| // |
| // One who gets non-null android::FileMap returned from this API is resposible |
| // for destroying it after the use. |
| android::FileMap *createMap(off_t pOffset, size_t pLength, bool pIsReadOnly); |
| |
| size_t getSize(); |
| |
| off_t seek(off_t pOffset); |
| off_t tell(); |
| |
| inline bool hasError() const |
| { return (mError.value() != llvm::errc::success); } |
| |
| inline const llvm::error_code &getError() const |
| { return mError; } |
| |
| // The return value of llvm::error_code::message() is obtained upon the call |
| // and is passed by value (that is, it's not a member of llvm::error_code.) |
| inline std::string getErrorMessage() const |
| { return mError.message(); } |
| |
| inline const std::string &getName() const |
| { return mName; } |
| |
| void close(); |
| |
| virtual ~FileBase(); |
| }; |
| |
| } // end namespace bcc |
| |
| #endif // BCC_EXECUTION_ENGINE_FILE_BASE_H |