2 * Copyright 2015 Facebook, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
22 #include <sys/types.h>
27 #include <folly/Portability.h>
28 #include <folly/Range.h>
33 * A File represents an open file.
38 * Creates an empty File object, for late initialization.
43 * Create a File object from an existing file descriptor.
44 * Takes ownership of the file descriptor if ownsFd is true.
46 explicit File(int fd, bool ownsFd = false);
49 * Open and create a file object. Throws on error.
51 explicit File(const char* name, int flags = O_RDONLY, mode_t mode = 0666);
53 const std::string& name, int flags = O_RDONLY, mode_t mode = 0666);
54 explicit File(StringPiece name, int flags = O_RDONLY, mode_t mode = 0666);
59 * Create and return a temporary, owned file (uses tmpfile()).
61 static File temporary();
64 * Return the file descriptor, or -1 if the file was closed.
66 int fd() const { return fd_; }
69 * Returns 'true' iff the file was successfully opened.
71 explicit operator bool() const {
76 * Duplicate file descriptor and return File that owns it.
81 * If we own the file descriptor, close the file and throw on error.
82 * Otherwise, do nothing.
87 * Closes the file (if owned). Returns true on success, false (and sets
93 * Returns and releases the file descriptor; no longer owned by this File.
94 * Returns -1 if the File object didn't wrap a file.
96 int release() noexcept;
99 * Swap this File with another.
101 void swap(File& other);
104 File(File&&) noexcept;
105 File& operator=(File&&);
107 // FLOCK (INTERPROCESS) LOCKS
109 // NOTE THAT THESE LOCKS ARE flock() LOCKS. That is, they may only be used
110 // for inter-process synchronization -- an attempt to acquire a second lock
111 // on the same file descriptor from the same process may succeed. Attempting
112 // to acquire a second lock on a different file descriptor for the same file
113 // should fail, but some systems might implement flock() using fcntl() locks,
114 // in which case it will succeed.
120 bool try_lock_shared();
121 void unlock_shared();
125 bool doTryLock(int op);
128 File(const File&) = delete;
129 File& operator=(const File&) = delete;
135 void swap(File& a, File& b);
140 #endif /* FOLLY_FILE_H_ */