Add portability header for sys/file.h

Summary: We don't have it on Windows :(

Reviewed By: yfeldblum

Differential Revision: D2978397

fb-gh-sync-id: 388bc450ce269559825ebfb78e3646533c2e1153
shipit-source-id: 388bc450ce269559825ebfb78e3646533c2e1153

folly/Makefile.am

@@ -274,6 +274,7 @@ nobase_follyinclude_HEADERS = \
 	portability/Memory.h \
 	portability/Strings.h \
 	portability/Syscall.h \
+	portability/SysFile.h \
 	portability/SysStat.h \
 	portability/SysTime.h \
 	portability/SysTypes.h \
@@ -407,6 +408,7 @@ libfolly_la_SOURCES = \
 	MemoryMapping.cpp \
 	portability/Environment.cpp \
 	portability/Strings.cpp \
+	portability/SysFile.cpp \
 	portability/SysStat.cpp \
 	portability/SysTime.cpp \
 	portability/Time.cpp \

folly/portability/SysFile.cpp

+/*
+ * Copyright 2016 Facebook, Inc.
+ *
+ * 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.
+ */
+
+#include <folly/portability/SysFile.h>
+
+#ifdef _WIN32
+#include <limits>
+
+#include <folly/portability/Windows.h>
+
+extern "C" int flock(int fd, int operation) {
+  HANDLE h = (HANDLE)_get_osfhandle(fd);
+  if (h == INVALID_HANDLE_VALUE) {
+    return -1;
+  }
+
+  constexpr DWORD kMaxDWORD = std::numeric_limits<DWORD>::max();
+  if (operation & LOCK_UN) {
+    if (!UnlockFile(h, 0, 0, kMaxDWORD, kMaxDWORD)) {
+      return -1;
+    }
+  } else {
+    int flags = 0
+        | (operation & LOCK_NB ? LOCKFILE_FAIL_IMMEDIATELY : 0)
+        | (operation & LOCK_EX ? LOCKFILE_EXCLUSIVE_LOCK : 0)
+        ;
+    OVERLAPPED ov = {};
+    if (!LockFileEx(h, flags, 0, kMaxDWORD, kMaxDWORD, &ov)) {
+      return -1;
+    }
+  }
+  return 0;
+}
+#endif

folly/portability/SysFile.h

+/*
+ * Copyright 2016 Facebook, Inc.
+ *
+ * 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.
+ */
+
+#pragma once
+
+#ifndef _WIN32
+#include <sys/file.h>
+#else
+#define LOCK_SH 1
+#define LOCK_EX 2
+#define LOCK_NB 4
+#define LOCK_UN 8
+extern "C" int flock(int fd, int operation);
+#endif