Add support for file locking

runtime/bin/file.h

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef BIN_FILE_H_
 #define BIN_FILE_H_
 
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
@@ skipping 51 matching lines @@
     // These match the constants in FileStat in file_system_entity.dart.
     kType = 0,
     kCreatedTime = 1,
     kModifiedTime = 2,
     kAccessedTime = 3,
     kMode = 4,
     kSize = 5,
     kStatSize = 6
   };
 
+  enum LockType {
+    // These match the constants in FileStat in file_impl.dart.
+    kLockMin = 0,
+    kLockUnlock = 0,
+    kLockShared = 1,
+    kLockExclusive = 2,
+    kLockMax = 2
+  };
+
   ~File();
 
   intptr_t GetFD();
 
   // Read/Write attempt to transfer num_bytes to/from buffer. It returns
   // the number of bytes read/written.
   int64_t Read(void* buffer, int64_t num_bytes);
   int64_t Write(const void* buffer, int64_t num_bytes);
 
   // ReadFully and WriteFully do attempt to transfer num_bytes to/from
@@ skipping 16 matching lines @@
 
   // Set the byte position in the file.
   bool SetPosition(int64_t position);
 
   // Truncate (or extend) the file to the given length in bytes.
   bool Truncate(int64_t length);
 
   // Flush contents of file.
   bool Flush();
 
+  // Lock range of a file.
+  bool Lock(LockType lock, int64_t start, int64_t end);
+
   // Returns whether the file has been closed.
   bool IsClosed();
 
   // Open the file with the given path. The file is always opened for
   // reading. If mode contains kWrite the file is opened for both
   // reading and writing. If mode contains kWrite and the file does
   // not exist the file is created. The file is truncated to length 0 if
   // mode contains kTruncate.
   static File* Open(const char* path, FileOpenMode mode);
 
@@ skipping 43 matching lines @@
   static CObject* ReadRequest(const CObjectArray& request);
   static CObject* ReadIntoRequest(const CObjectArray& request);
   static CObject* WriteFromRequest(const CObjectArray& request);
   static CObject* CreateLinkRequest(const CObjectArray& request);
   static CObject* DeleteLinkRequest(const CObjectArray& request);
   static CObject* RenameLinkRequest(const CObjectArray& request);
   static CObject* LinkTargetRequest(const CObjectArray& request);
   static CObject* TypeRequest(const CObjectArray& request);
   static CObject* IdenticalRequest(const CObjectArray& request);
   static CObject* StatRequest(const CObjectArray& request);
+  static CObject* LockRequest(const CObjectArray& request);
 
  private:
   explicit File(FileHandle* handle) : handle_(handle) { }
   void Close();
 
   static const int kClosedFd = -1;
 
   // FileHandle is an OS specific class which stores data about the file.
   FileHandle* handle_;  // OS specific handle for the file.
 
   DISALLOW_COPY_AND_ASSIGN(File);
 };
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // BIN_FILE_H_