namespace folly {
-File::File()
- : fd_(-1)
- , ownsFd_(false)
-{}
-
-File::File(int fd, bool ownsFd)
- : fd_(fd)
- , ownsFd_(ownsFd) {
+File::File() noexcept : fd_(-1), ownsFd_(false) {}
+
+File::File(int fd, bool ownsFd) noexcept : fd_(fd), ownsFd_(ownsFd) {
CHECK_GE(fd, -1) << "fd must be -1 or non-negative";
CHECK(fd != -1 || !ownsFd) << "cannot own -1";
}
#include <sys/types.h>
#include <string>
+#include <system_error>
+#include <folly/ExceptionWrapper.h>
+#include <folly/Expected.h>
#include <folly/Portability.h>
#include <folly/Range.h>
#include <folly/portability/Unistd.h>
/**
* Creates an empty File object, for late initialization.
*/
- File();
+ File() noexcept;
/**
* Create a File object from an existing file descriptor.
* Takes ownership of the file descriptor if ownsFd is true.
*/
- explicit File(int fd, bool ownsFd = false);
+ explicit File(int fd, bool ownsFd = false) noexcept;
/**
* Open and create a file object. Throws on error.
const std::string& name, int flags = O_RDONLY, mode_t mode = 0666);
explicit File(StringPiece name, int flags = O_RDONLY, mode_t mode = 0666);
+ /**
+ * All the constructors that are not noexcept can throw std::system_error.
+ * This is a helper method to use folly::Expected to chain a file open event
+ * to something else you want to do with the open fd.
+ */
+ template <typename... Args>
+ static Expected<File, exception_wrapper> makeFile(Args&&... args) noexcept {
+ try {
+ return File(std::forward<Args>(args)...);
+ } catch (const std::system_error& se) {
+ return makeUnexpected(exception_wrapper(std::current_exception(), se));
+ }
+ }
+
~File();
/**
EXPECT_TRUE(false);
}
}
+
+TEST(File, HelperCtor) {
+ File::makeFile(StringPiece("/etc/hosts")).then([](File&& f) {
+ char buf = 'x';
+ EXPECT_NE(-1, f.fd());
+ EXPECT_EQ(1, ::read(f.fd(), &buf, 1));
+ f.close();
+ EXPECT_EQ(-1, f.fd());
+ });
+}