text: // Copyright Joyent, Inc. and other Node contributors.
  //
  // Permission is hereby granted, free of charge, to any person obtaining a
  // copy of this software and associated documentation files (the
  // "Software"), to deal in the Software without restriction, including
  // without limitation the rights to use, copy, modify, merge, publish,
  // distribute, sublicense, and/or sell copies of the Software, and to permit
  // persons to whom the Software is furnished to do so, subject to the
  // following conditions:
  //
  // The above copyright notice and this permission notice shall be included
  // in all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
  // NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
  // DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  // USE OR OTHER DEALINGS IN THE SOFTWARE.
  
  #include "node.h"
  #include "node_file.h"
  #include "node_buffer.h"
  #include "node_internals.h"
  #include "node_stat_watcher.h"
  
  #include "env.h"
  #include "env-inl.h"
  #include "req_wrap.h"
  #include "string_bytes.h"
  #include "util.h"
  
  #include <fcntl.h>
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <assert.h>
  #include <string.h>
  #include <errno.h>
  #include <limits.h>
  
  #if defined(__MINGW32__) || defined(_MSC_VER)
  # include <io.h>
  #endif
  
  namespace node {
  
  using v8::Array;
  using v8::Context;
  using v8::EscapableHandleScope;
  using v8::Function;
  using v8::FunctionCallbackInfo;
  using v8::FunctionTemplate;
  using v8::Handle;
  using v8::HandleScope;
  using v8::Integer;
  using v8::Local;
  using v8::Number;
  using v8::Object;
  using v8::String;
  using v8::Value;
  
  #define MIN(a, b) ((a) < (b) ? (a) : (b))
  
  #define TYPE_ERROR(msg) env->ThrowTypeError(msg)
  
  #define THROW_BAD_ARGS TYPE_ERROR("Bad argument")
  
  class FSReqWrap: public ReqWrap<uv_fs_t> {
   public:
    void* operator new(size_t size) { return new char[size]; }
    void* operator new(size_t size, char* storage) { return storage; }
  
    FSReqWrap(Environment* env, const char* syscall, char* data = NULL)
      : ReqWrap<uv_fs_t>(env, Object::New(env->isolate())),
        syscall_(syscall),
        data_(data),
        dest_len_(0) {
    }
  
    void ReleaseEarly() {
      if (data_ == NULL)
        return;
      delete[] data_;
      data_ = NULL;
    }
  
    inline const char* syscall() const { return syscall_; }
    inline const char* dest() const { return dest_; }
    inline unsigned int dest_len() const { return dest_len_; }
    inline void dest_len(unsigned int dest_len) { dest_len_ = dest_len; }
  
   private:
    const char* syscall_;
    char* data_;
    unsigned int dest_len_;
    char dest_[1];
  };
  
  
  #define ASSERT_OFFSET(a) \
    if (!(a)->IsUndefined() && !(a)->IsNull() && !IsInt64((a)->NumberValue())) { \
      return env->ThrowTypeError("Not an integer"); \
    }
  #define ASSERT_TRUNCATE_LENGTH(a) \
    if (!(a)->IsUndefined() && !(a)->IsNull() && !IsInt64((a)->NumberValue())) { \
      return env->ThrowTypeError("Not an integer"); \
    }
  #define GET_OFFSET(a) ((a)->IsNumber() ? (a)->IntegerValue() : -1)
  #define GET_TRUNCATE_LENGTH(a) ((a)->IntegerValue())
  
  static inline bool IsInt64(double x) {
    return x == static_cast<double>(static_cast<int64_t>(x));
  }
  
  
  static void After(uv_fs_t *req) {
    FSReqWrap* req_wrap = static_cast<FSReqWrap*>(req->data);
    assert(&req_wrap->req_ == req);
    req_wrap->ReleaseEarly();  // Free memory that's no longer used now.
  
    Environment* env = req_wrap->env();
    HandleScope handle_scope(env->isolate());
    Context::Scope context_scope(env->context());
  
    // there is always at least one argument. "error"
    int argc = 1;
  
    // Allocate space for two args. We may only use one depending on the case.
    // (Feel free to increase this if you need more)
    Local<Value> argv[2];
  
    if (req->result < 0) {
      // If the request doesn't have a path parameter set.
      if (req->path == NULL) {
        argv[0] = UVException(req->result, NULL, req_wrap->syscall());
      } else if ((req->result == UV_EEXIST ||
                  req->result == UV_ENOTEMPTY ||
                  req->result == UV_EPERM) &&
                 req_wrap->dest_len() > 0) {
        argv[0] = UVException(req->result,
                              NULL,
                              req_wrap->syscall(),
                              req_wrap->dest());
      } else {
        argv[0] = UVException(req->result,
                              NULL,
                              req_wrap->syscall(),
                              static_cast<const char*>(req->path));
      }
    } else {
      // error value is empty or null for non-error.
      argv[0] = Null(env->isolate());
  
      // All have at least two args now.
      argc = 2;
  
      switch (req->fs_type) {
        // These all have no data to pass.
        case UV_FS_CLOSE:
        case UV_FS_RENAME:
        case UV_FS_UNLINK:
        case UV_FS_RMDIR:
        case UV_FS_MKDIR:
        case UV_FS_FTRUNCATE:
        case UV_FS_FSYNC:
        case UV_FS_FDATASYNC:
        case UV_FS_LINK:
        case UV_FS_SYMLINK:
        case UV_FS_CHMOD:
        case UV_FS_FCHMOD:
        case UV_FS_CHOWN:
        case UV_FS_FCHOWN:
          // These, however, don't.
          argc = 1;
          break;
  
        case UV_FS_UTIME:
        case UV_FS_FUTIME:
          argc = 0;
          break;
  
        case UV_FS_OPEN:
          argv[1] = Integer::New(env->isolate(), req->result);
          break;
  
        case UV_FS_WRITE:
          argv[1] = Integer::New(env->isolate(), req->result);
          break;
  
        case UV_FS_STAT:
        case UV_FS_LSTAT:
        case UV_FS_FSTAT:
          argv[1] = BuildStatsObject(env,
                                     static_cast<const uv_stat_t*>(req->ptr));
          break;
  
        case UV_FS_READLINK:
          argv[1] = String::NewFromUtf8(env->isolate(),
                                        static_cast<const char*>(req->ptr));
          break;
  
        case UV_FS_READ:
          // Buffer interface
          argv[1] = Integer::New(env->isolate(), req->result);
          break;
  
        case UV_FS_READDIR:
          {
            int r;
            Local<Array> names = Array::New(env->isolate(), 0);
  
            for (int i = 0; ; i++) {
              uv_dirent_t ent;
  
              r = uv_fs_readdir_next(req, &ent);
              if (r == UV_EOF)
                break;
              if (r != 0) {
                argv[0] = UVException(r,
                                      NULL,
                                      req_wrap->syscall(),
                                      static_cast<const char*>(req->path));
                break;
              }
  
              Local<String> name = String::NewFromUtf8(env->isolate(),
                                                       ent.name);
              names->Set(i, name);
            }
  
            argv[1] = names;
          }
          break;
  
        default:
          assert(0 && "Unhandled eio response");
      }
    }
  
    req_wrap->MakeCallback(env->oncomplete_string(), argc, argv);
  
    uv_fs_req_cleanup(&req_wrap->req_);
    delete req_wrap;
  }
  
  // This struct is only used on sync fs calls.
  // For async calls FSReqWrap is used.
  struct fs_req_wrap {
    fs_req_wrap() {}
    ~fs_req_wrap() { uv_fs_req_cleanup(&req); }
    // Ensure that copy ctor and assignment operator are not used.
    fs_req_wrap(const fs_req_wrap& req);
    fs_req_wrap& operator=(const fs_req_wrap& req);
    uv_fs_t req;
  };
  
  
  #define ASYNC_DEST_CALL(func, callback, dest_path, ...)                       \
    Environment* env = Environment::GetCurrent(args.GetIsolate());              \
    FSReqWrap* req_wrap;                                                        \
    char* dest_str = (dest_path);                                               \
    int dest_len = dest_str == NULL ? 0 : strlen(dest_str);                     \
    char* storage = new char[sizeof(*req_wrap) + dest_len];                     \
    req_wrap = new(storage) FSReqWrap(env, #func);                              \
    req_wrap->dest_len(dest_len);                                               \
    if (dest_str != NULL) {                                                     \
      memcpy(const_cast<char*>(req_wrap->dest()),                               \
             dest_str,                                                          \
             dest_len + 1);                                                     \
    }                                                                           \
    int err = uv_fs_ ## func(env->event_loop() ,                                \
                             &req_wrap->req_,                                   \
                             __VA_ARGS__,                                       \
                             After);                                            \
    req_wrap->object()->Set(env->oncomplete_string(), callback);                \
    req_wrap->Dispatched();                                                     \
    if (err < 0) {                                                              \
      uv_fs_t* req = &req_wrap->req_;                                           \
      req->result = err;                                                        \
      req->path = NULL;                                                         \
      After(req);                                                               \
    }                                                                           \
    args.GetReturnValue().Set(req_wrap->persistent());
  
  #define ASYNC_CALL(func, callback, ...)                                       \
    ASYNC_DEST_CALL(func, callback, NULL, __VA_ARGS__)                          \
  
  #define SYNC_DEST_CALL(func, path, dest, ...)                                 \
    fs_req_wrap req_wrap;                                                       \
    int err = uv_fs_ ## func(env->event_loop(),                                 \
                           &req_wrap.req,                                       \
                           __VA_ARGS__,                                         \
                           NULL);                                               \
    if (err < 0) {                                                              \
      if (dest != NULL &&                                                       \
          (err == UV_EEXIST ||                                                  \
           err == UV_ENOTEMPTY ||                                               \
           err == UV_EPERM)) {                                                  \
        return env->ThrowUVException(err, #func, "", dest);                     \
      } else {                                                                  \
        return env->ThrowUVException(err, #func, "", path);                     \
      }                                                                         \
    }                                                                           \
  
  #define SYNC_CALL(func, path, ...)                                            \
    SYNC_DEST_CALL(func, path, NULL, __VA_ARGS__)                               \
  
  #define SYNC_REQ req_wrap.req
  
  #define SYNC_RESULT err
  
  
  static void Close(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    if (args.Length() < 1 || !args[0]->IsInt32()) {
      return THROW_BAD_ARGS;
    }
  
    int fd = args[0]->Int32Value();
  
    if (args[1]->IsFunction()) {
      ASYNC_CALL(close, args[1], fd)
    } else {
      SYNC_CALL(close, 0, fd)
    }
  }
  
  
  Local<Value> BuildStatsObject(Environment* env, const uv_stat_t* s) {
    // If you hit this assertion, you forgot to enter the v8::Context first.
    assert(env->context() == env->isolate()->GetCurrentContext());
  
    EscapableHandleScope handle_scope(env->isolate());
  
    // The code below is very nasty-looking but it prevents a segmentation fault
    // when people run JS code like the snippet below. It's apparently more
    // common than you would expect, several people have reported this crash...
    //
    //   function crash() {
    //     fs.statSync('.');
    //     crash();
    //   }
    //
    // We need to check the return value of Integer::New() and Date::New()
    // and make sure that we bail out when V8 returns an empty handle.
  
    // Integers.
  #define X(name)                                                               \
    Local<Value> name = Integer::New(env->isolate(), s->st_##name);             \
    if (name.IsEmpty())                                                         \
      return handle_scope.Escape(Local<Object>());                              \
  
    X(dev)
    X(mode)
    X(nlink)
    X(uid)
    X(gid)
    X(rdev)
  # if defined(__POSIX__)
    X(blksize)
  # else
    Local<Value> blksize = Undefined(env->isolate());
  # endif
  #undef X
  
    // Numbers.
  #define X(name)                                                               \
    Local<Value> name = Number::New(env->isolate(),                             \
                                    static_cast<double>(s->st_##name));         \
    if (name.IsEmpty())                                                         \
      return handle_scope.Escape(Local<Object>());                              \
  
    X(ino)
    X(size)
  # if defined(__POSIX__)
    X(blocks)
  # else
    Local<Value> blocks = Undefined(env->isolate());
  # endif
  #undef X
  
    // Dates.
  #define X(name)                                                               \
    Local<Value> name##_msec =                                                  \
      Number::New(env->isolate(),                                               \
          (static_cast<double>(s->st_##name.tv_sec) * 1000) +                   \
          (static_cast<double>(s->st_##name.tv_nsec / 1000000)));               \
                                                                                \
    if (name##_msec.IsEmpty())                                                  \
      return handle_scope.Escape(Local<Object>());                              \
  
    X(atim)
    X(mtim)
    X(ctim)
    X(birthtim)
  #undef X
  
    // Pass stats as the first argument, this is the object we are modifying.
    Local<Value> argv[] = {
      dev,
      mode,
      nlink,
      uid,
      gid,
      rdev,
      blksize,
      ino,
      size,
      blocks,
      atim_msec,
      mtim_msec,
      ctim_msec,
      birthtim_msec
    };
  
    // Call out to JavaScript to create the stats object.
    Local<Value> stats =
      env->fs_stats_constructor_function()->NewInstance(ARRAY_SIZE(argv), argv);
  
    if (stats.IsEmpty())
      return handle_scope.Escape(Local<Object>());
  
    return handle_scope.Escape(stats);
  }
  
  static void Stat(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    if (args.Length() < 1)
      return TYPE_ERROR("path required");
    if (!args[0]->IsString())
      return TYPE_ERROR("path must be a string");
  
    node::Utf8Value path(args[0]);
  
    if (args[1]->IsFunction()) {
      ASYNC_CALL(stat, args[1], *path)
    } else {
      SYNC_CALL(stat, *path, *path)
      args.GetReturnValue().Set(
          BuildStatsObject(env, static_cast<const uv_stat_t*>(SYNC_REQ.ptr)));
    }
  }
  
  static void StatNoException(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    if (args.Length() < 1 || !args[0]->IsString()) {
      args.GetReturnValue().Set(v8::Boolean::New(env->isolate(), false));
      return;
    }
  
    String::Utf8Value path(args[0]);
  
    fs_req_wrap req_wrap;
    int result = uv_fs_stat(uv_default_loop(), &req_wrap.req, *path, NULL);
    if (result < 0)
      args.GetReturnValue().Set(v8::Boolean::New(env->isolate(), false));
    else
      args.GetReturnValue().Set(
          BuildStatsObject(env, static_cast<const uv_stat_t*>(SYNC_REQ.ptr)));
  }
  
  static void LStat(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    if (args.Length() < 1)
      return TYPE_ERROR("path required");
    if (!args[0]->IsString())
      return TYPE_ERROR("path must be a string");
  
    node::Utf8Value path(args[0]);
  
    if (args[1]->IsFunction()) {
      ASYNC_CALL(lstat, args[1], *path)
    } else {
      SYNC_CALL(lstat, *path, *path)
      args.GetReturnValue().Set(
          BuildStatsObject(env, static_cast<const uv_stat_t*>(SYNC_REQ.ptr)));
    }
  }
  
  static void LStatNoException(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    String::Utf8Value path(args[0]);
  
    if (args.Length() < 1 || !args[0]->IsString()) {
      args.GetReturnValue().Set(v8::Boolean::New(env->isolate(), false));
      return;
    }
  
    fs_req_wrap req_wrap;
    int result = uv_fs_lstat(uv_default_loop(), &req_wrap.req, *path, NULL);
    if (result < 0)
      args.GetReturnValue().Set(v8::Boolean::New(env->isolate(), false));
    else
      args.GetReturnValue().Set(
          BuildStatsObject(env, static_cast<const uv_stat_t*>(SYNC_REQ.ptr)));
  }
  
  static void FStat(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    if (args.Length() < 1 || !args[0]->IsInt32()) {
      return THROW_BAD_ARGS;
    }
  
    int fd = args[0]->Int32Value();
  
    if (args[1]->IsFunction()) {
      ASYNC_CALL(fstat, args[1], fd)
    } else {
      SYNC_CALL(fstat, 0, fd)
      args.GetReturnValue().Set(
          BuildStatsObject(env, static_cast<const uv_stat_t*>(SYNC_REQ.ptr)));
    }
  }
  
  static void Symlink(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    int len = args.Length();
    if (len < 1)
      return TYPE_ERROR("dest path required");
    if (len < 2)
      return TYPE_ERROR("src path required");
    if (!args[0]->IsString())
      return TYPE_ERROR("dest path must be a string");
    if (!args[1]->IsString())
      return TYPE_ERROR("src path must be a string");
  
    node::Utf8Value dest(args[0]);
    node::Utf8Value path(args[1]);
    int flags = 0;
  
    if (args[2]->IsString()) {
      node::Utf8Value mode(args[2]);
      if (strcmp(*mode, "dir") == 0) {
        flags |= UV_FS_SYMLINK_DIR;
      } else if (strcmp(*mode, "junction") == 0) {
        flags |= UV_FS_SYMLINK_JUNCTION;
      } else if (strcmp(*mode, "file") != 0) {
        return env->ThrowError("Unknown symlink type");
      }
    }
  
    if (args[3]->IsFunction()) {
      ASYNC_DEST_CALL(symlink, args[3], *dest, *dest, *path, flags)
    } else {
      SYNC_DEST_CALL(symlink, *path, *dest, *dest, *path, flags)
    }
  }
  
  static void Link(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    int len = args.Length();
    if (len < 1)
      return TYPE_ERROR("dest path required");
    if (len < 2)
      return TYPE_ERROR("src path required");
    if (!args[0]->IsString())
      return TYPE_ERROR("dest path must be a string");
    if (!args[1]->IsString())
      return TYPE_ERROR("src path must be a string");
  
    node::Utf8Value orig_path(args[0]);
    node::Utf8Value new_path(args[1]);
  
    if (args[2]->IsFunction()) {
      ASYNC_DEST_CALL(link, args[2], *new_path, *orig_path, *new_path)
    } else {
      SYNC_DEST_CALL(link, *orig_path, *new_path, *orig_path, *new_path)
    }
  }
  
  static void ReadLink(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    if (args.Length() < 1)
      return TYPE_ERROR("path required");
    if (!args[0]->IsString())
      return TYPE_ERROR("path must be a string");
  
    node::Utf8Value path(args[0]);
  
    if (args[1]->IsFunction()) {
      ASYNC_CALL(readlink, args[1], *path)
    } else {
      SYNC_CALL(readlink, *path, *path)
      const char* link_path = static_cast<const char*>(SYNC_REQ.ptr);
      Local<String> rc = String::NewFromUtf8(env->isolate(), link_path);
      args.GetReturnValue().Set(rc);
    }
  }
  
  static void Rename(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    int len = args.Length();
    if (len < 1)
      return TYPE_ERROR("old path required");
    if (len < 2)
      return TYPE_ERROR("new path required");
    if (!args[0]->IsString())
      return TYPE_ERROR("old path must be a string");
    if (!args[1]->IsString())
      return TYPE_ERROR("new path must be a string");
  
    node::Utf8Value old_path(args[0]);
    node::Utf8Value new_path(args[1]);
  
    if (args[2]->IsFunction()) {
      ASYNC_DEST_CALL(rename, args[2], *new_path, *old_path, *new_path)
    } else {
      SYNC_DEST_CALL(rename, *old_path, *new_path, *old_path, *new_path)
    }
  }
  
  static void FTruncate(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    if (args.Length() < 2 || !args[0]->IsInt32()) {
      return THROW_BAD_ARGS;
    }
  
    int fd = args[0]->Int32Value();
  
    ASSERT_TRUNCATE_LENGTH(args[1]);
    int64_t len = GET_TRUNCATE_LENGTH(args[1]);
  
    if (args[2]->IsFunction()) {
      ASYNC_CALL(ftruncate, args[2], fd, len)
    } else {
      SYNC_CALL(ftruncate, 0, fd, len)
    }
  }
  
  static void Fdatasync(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    if (args.Length() < 1 || !args[0]->IsInt32()) {
      return THROW_BAD_ARGS;
    }
  
    int fd = args[0]->Int32Value();
  
    if (args[1]->IsFunction()) {
      ASYNC_CALL(fdatasync, args[1], fd)
    } else {
      SYNC_CALL(fdatasync, 0, fd)
    }
  }
  
  static void Fsync(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    if (args.Length() < 1 || !args[0]->IsInt32()) {
      return THROW_BAD_ARGS;
    }
  
    int fd = args[0]->Int32Value();
  
    if (args[1]->IsFunction()) {
      ASYNC_CALL(fsync, args[1], fd)
    } else {
      SYNC_CALL(fsync, 0, fd)
    }
  }
  
  static void Unlink(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    if (args.Length() < 1)
      return TYPE_ERROR("path required");
    if (!args[0]->IsString())
      return TYPE_ERROR("path must be a string");
  
    node::Utf8Value path(args[0]);
  
    if (args[1]->IsFunction()) {
      ASYNC_CALL(unlink, args[1], *path)
    } else {
      SYNC_CALL(unlink, *path, *path)
    }
  }
  
  static void RMDir(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    if (args.Length() < 1)
      return TYPE_ERROR("path required");
    if (!args[0]->IsString())
      return TYPE_ERROR("path must be a string");
  
    node::Utf8Value path(args[0]);
  
    if (args[1]->IsFunction()) {
      ASYNC_CALL(rmdir, args[1], *path)
    } else {
      SYNC_CALL(rmdir, *path, *path)
    }
  }
  
  static void MKDir(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    if (args.Length() < 2 || !args[0]->IsString() || !args[1]->IsInt32()) {
      return THROW_BAD_ARGS;
    }
  
    node::Utf8Value path(args[0]);
    int mode = static_cast<int>(args[1]->Int32Value());
  
    if (args[2]->IsFunction()) {
      ASYNC_CALL(mkdir, args[2], *path, mode)
    } else {
      SYNC_CALL(mkdir, *path, *path, mode)
    }
  }
  
  static void ReadDir(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    if (args.Length() < 1)
      return TYPE_ERROR("path required");
    if (!args[0]->IsString())
      return TYPE_ERROR("path must be a string");
  
    node::Utf8Value path(args[0]);
  
    if (args[1]->IsFunction()) {
      ASYNC_CALL(readdir, args[1], *path, 0 /*flags*/)
    } else {
      SYNC_CALL(readdir, *path, *path, 0 /*flags*/)
  
      assert(SYNC_REQ.result >= 0);
      int r;
      Local<Array> names = Array::New(env->isolate(), 0);
  
      for (int i = 0; ; i++) {
        uv_dirent_t ent;
  
        r = uv_fs_readdir_next(&SYNC_REQ, &ent);
        if (r == UV_EOF)
          break;
        if (r != 0)
          return env->ThrowUVException(r, "readdir", "", *path);
  
        Local<String> name = String::NewFromUtf8(env->isolate(),
                                                 ent.name);
        names->Set(i, name);
      }
  
      args.GetReturnValue().Set(names);
    }
  }
  
  static void Open(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    int len = args.Length();
    if (len < 1)
      return TYPE_ERROR("path required");
    if (len < 2)
      return TYPE_ERROR("flags required");
    if (len < 3)
      return TYPE_ERROR("mode required");
    if (!args[0]->IsString())
      return TYPE_ERROR("path must be a string");
    if (!args[1]->IsInt32())
      return TYPE_ERROR("flags must be an int");
    if (!args[2]->IsInt32())
      return TYPE_ERROR("mode must be an int");
  
    node::Utf8Value path(args[0]);
    int flags = args[1]->Int32Value();
    int mode = static_cast<int>(args[2]->Int32Value());
  
    if (args[3]->IsFunction()) {
      ASYNC_CALL(open, args[3], *path, flags, mode)
    } else {
      SYNC_CALL(open, *path, *path, flags, mode)
      args.GetReturnValue().Set(SYNC_RESULT);
    }
  }
  
  
  // Wrapper for write(2).
  //
  // bytesWritten = write(fd, buffer, offset, length, position, callback)
  // 0 fd        integer. file descriptor
  // 1 buffer    the data to write
  // 2 offset    where in the buffer to start from
  // 3 length    how much to write
  // 4 position  if integer, position to write at in the file.
  //             if null, write from the current position
  static void WriteBuffer(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    assert(args[0]->IsInt32());
    assert(Buffer::HasInstance(args[1]));
  
    int fd = args[0]->Int32Value();
    Local<Object> obj = args[1].As<Object>();
    const char* buf = Buffer::Data(obj);
    size_t buffer_length = Buffer::Length(obj);
    size_t off = args[2]->Uint32Value();
    size_t len = args[3]->Uint32Value();
    int64_t pos = GET_OFFSET(args[4]);
    Local<Value> cb = args[5];
  
    if (off > buffer_length)
      return env->ThrowRangeError("offset out of bounds");
    if (len > buffer_length)
      return env->ThrowRangeError("length out of bounds");
    if (off + len < off)
      return env->ThrowRangeError("off + len overflow");
    if (!Buffer::IsWithinBounds(off, len, buffer_length))
      return env->ThrowRangeError("off + len > buffer.length");
  
    buf += off;
  
    uv_buf_t uvbuf = uv_buf_init(const_cast<char*>(buf), len);
  
    if (cb->IsFunction()) {
      ASYNC_CALL(write, cb, fd, &uvbuf, 1, pos)
      return;
    }
  
    SYNC_CALL(write, NULL, fd, &uvbuf, 1, pos)
    args.GetReturnValue().Set(SYNC_RESULT);
  }
  
  
  // Wrapper for write(2).
  //
  // bytesWritten = write(fd, string, position, enc, callback)
  // 0 fd        integer. file descriptor
  // 1 string    non-buffer values are converted to strings
  // 2 position  if integer, position to write at in the file.
  //             if null, write from the current position
  // 3 enc       encoding of string
  static void WriteString(const FunctionCallbackInfo<Value>& args) {
    HandleScope handle_scope(args.GetIsolate());
    Environment* env = Environment::GetCurrent(args.GetIsolate());
  
    if (!args[0]->IsInt32())
      return env->ThrowTypeError("First argument must be file descriptor");
  
    Local<Value> cb;
    Local<Value> string = args[1];
    int fd = args[0]->Int32Value();
    char* buf = NULL;
    int64_t pos;
    size_t len;
    bool must_free = false;
  
    // will assign buf and len if string was external
    if (!StringBytes::GetExternalParts(env->isolate(),
                                       string,
                                       const_cast<const char**>(&buf),
                                       &len)) {
      enum encoding enc = ParseEncoding(env->isolate(), args[3], UTF8);
      len = StringBytes::StorageSize(env->isolate(), string, enc);
      buf = new char[len];
      // StorageSize may return too large a char, so correct the actual length
      // by the write size
      len = StringBytes::Write(env->isolate(), buf, len, args[1], enc);
      must_free = true;
    }
    pos = GET_OFFSET(args[2]);
    cb = args[4];
  
    uv_buf_t uvbuf = uv_buf_init(const_cast<char*>(buf), len);
  
    if (!cb->IsFunction()) {
      SYNC_CALL(write, NULL, fd, &uvbuf, 1, pos)
      if (must_free)
        delete[] buf;
      return args.GetReturnValue().Set(SYNC_RESULT);
    }
  
    FSReqWrap* req_wrap = new FSReqWrap(env, "write", must_free ? buf : NULL);
    int err = uv_fs_write(env->event_loop(),
                          &req_wrap->req_,
                          fd,
                          &uvbuf,
                          1,
                          pos,
                          After);
    req_wrap->object()->Set(env->oncomplete_string(), cb);
    req_wrap->Dispatched();
    if (err < 0) {
      uv_fs_t* req = &req_wrap->req_;
      req->result = err;
      req->path = NULL;
      After(req);
    }
  
    return args.GetReturnValue().Set(req_wrap->persistent());
  }
  
  
  /*
   * Wrapper for read(2).
   *
   * bytesRead = fs.read(fd, buffer, offset, length, position)
   *
   * 0 fd        integer. file descriptor
   * 1 buffer    instance of Buffer
   * 2 offset    integer. offset to start reading into inside buffer
   * 3 length    integer. length to read
   * 4 position  file position - null for current position
   *
   */
  static void Read(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    if (args.Length() < 2 || !args[0]->IsInt32()) {
      return THROW_BAD_ARGS;
    }
  
    int fd = args[0]->Int32Value();
  
    Local<Value> cb;
  
    size_t len;
    int64_t pos;
  
    char * buf = NULL;
  
    if (!Buffer::HasInstance(args[1])) {
      return env->ThrowError("Second argument needs to be a buffer");
    }
  
    Local<Object> buffer_obj = args[1]->ToObject();
    char *buffer_data = Buffer::Data(buffer_obj);
    size_t buffer_length = Buffer::Length(buffer_obj);
  
    size_t off = args[2]->Int32Value();
    if (off >= buffer_length) {
      return env->ThrowError("Offset is out of bounds");
    }
  
    len = args[3]->Int32Value();
    if (!Buffer::IsWithinBounds(off, len, buffer_length))
      return env->ThrowRangeError("Length extends beyond buffer");
  
    pos = GET_OFFSET(args[4]);
  
    buf = buffer_data + off;
  
    uv_buf_t uvbuf = uv_buf_init(const_cast<char*>(buf), len);
  
    cb = args[5];
  
    if (cb->IsFunction()) {
      ASYNC_CALL(read, cb, fd, &uvbuf, 1, pos);
    } else {
      SYNC_CALL(read, 0, fd, &uvbuf, 1, pos)
      args.GetReturnValue().Set(SYNC_RESULT);
    }
  }
  
  
  /* fs.chmod(path, mode);
   * Wrapper for chmod(1) / EIO_CHMOD
   */
  static void Chmod(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    if (args.Length() < 2 || !args[0]->IsString() || !args[1]->IsInt32()) {
      return THROW_BAD_ARGS;
    }
    node::Utf8Value path(args[0]);
    int mode = static_cast<int>(args[1]->Int32Value());
  
    if (args[2]->IsFunction()) {
      ASYNC_CALL(chmod, args[2], *path, mode);
    } else {
      SYNC_CALL(chmod, *path, *path, mode);
    }
  }
  
  
  /* fs.fchmod(fd, mode);
   * Wrapper for fchmod(1) / EIO_FCHMOD
   */
  static void FChmod(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    if (args.Length() < 2 || !args[0]->IsInt32() || !args[1]->IsInt32()) {
      return THROW_BAD_ARGS;
    }
    int fd = args[0]->Int32Value();
    int mode = static_cast<int>(args[1]->Int32Value());
  
    if (args[2]->IsFunction()) {
      ASYNC_CALL(fchmod, args[2], fd, mode);
    } else {
      SYNC_CALL(fchmod, 0, fd, mode);
    }
  }
  
  
  /* fs.chown(path, uid, gid);
   * Wrapper for chown(1) / EIO_CHOWN
   */
  static void Chown(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    int len = args.Length();
    if (len < 1)
      return TYPE_ERROR("path required");
    if (len < 2)
      return TYPE_ERROR("uid required");
    if (len < 3)
      return TYPE_ERROR("gid required");
    if (!args[0]->IsString())
      return TYPE_ERROR("path must be a string");
    if (!args[1]->IsUint32())
      return TYPE_ERROR("uid must be an unsigned int");
    if (!args[2]->IsUint32())
      return TYPE_ERROR("gid must be an unsigned int");
  
    node::Utf8Value path(args[0]);
    uv_uid_t uid = static_cast<uv_uid_t>(args[1]->Uint32Value());
    uv_gid_t gid = static_cast<uv_gid_t>(args[2]->Uint32Value());
  
    if (args[3]->IsFunction()) {
      ASYNC_CALL(chown, args[3], *path, uid, gid);
    } else {
      SYNC_CALL(chown, *path, *path, uid, gid);
    }
  }
  
  
  /* fs.fchown(fd, uid, gid);
   * Wrapper for fchown(1) / EIO_FCHOWN
   */
  static void FChown(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    int len = args.Length();
    if (len < 1)
      return TYPE_ERROR("fd required");
    if (len < 2)
      return TYPE_ERROR("uid required");
    if (len < 3)
      return TYPE_ERROR("gid required");
    if (!args[0]->IsInt32())
      return TYPE_ERROR("fd must be an int");
    if (!args[1]->IsUint32())
      return TYPE_ERROR("uid must be an unsigned int");
    if (!args[2]->IsUint32())
      return TYPE_ERROR("gid must be an unsigned int");
  
    int fd = args[0]->Int32Value();
    uv_uid_t uid = static_cast<uv_uid_t>(args[1]->Uint32Value());
    uv_gid_t gid = static_cast<uv_gid_t>(args[2]->Uint32Value());
  
    if (args[3]->IsFunction()) {
      ASYNC_CALL(fchown, args[3], fd, uid, gid);
    } else {
      SYNC_CALL(fchown, 0, fd, uid, gid);
    }
  }
  
  
  static void UTimes(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    int len = args.Length();
    if (len < 1)
      return TYPE_ERROR("path required");
    if (len < 2)
      return TYPE_ERROR("atime required");
    if (len < 3)
      return TYPE_ERROR("mtime required");
    if (!args[0]->IsString())
      return TYPE_ERROR("path must be a string");
    if (!args[1]->IsNumber())
      return TYPE_ERROR("atime must be a number");
    if (!args[2]->IsNumber())
      return TYPE_ERROR("mtime must be a number");
  
    const node::Utf8Value path(args[0]);
    const double atime = static_cast<double>(args[1]->NumberValue());
    const double mtime = static_cast<double>(args[2]->NumberValue());
  
    if (args[3]->IsFunction()) {
      ASYNC_CALL(utime, args[3], *path, atime, mtime);
    } else {
      SYNC_CALL(utime, *path, *path, atime, mtime);
    }
  }
  
  static void FUTimes(const FunctionCallbackInfo<Value>& args) {
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    HandleScope scope(env->isolate());
  
    int len = args.Length();
    if (len < 1)
      return TYPE_ERROR("fd required");
    if (len < 2)
      return TYPE_ERROR("atime required");
    if (len < 3)
      return TYPE_ERROR("mtime required");
    if (!args[0]->IsInt32())
      return TYPE_ERROR("fd must be an int");
    if (!args[1]->IsNumber())
      return TYPE_ERROR("atime must be a number");
    if (!args[2]->IsNumber())
      return TYPE_ERROR("mtime must be a number");
  
    const int fd = args[0]->Int32Value();
    const double atime = static_cast<double>(args[1]->NumberValue());
    const double mtime = static_cast<double>(args[2]->NumberValue());
  
    if (args[3]->IsFunction()) {
      ASYNC_CALL(futime, args[3], fd, atime, mtime);
    } else {
      SYNC_CALL(futime, 0, fd, atime, mtime);
    }
  }
  
  void FSInitialize(const FunctionCallbackInfo<Value>& args) {
    Local<Function> stats_constructor = args[0].As<Function>();
    assert(stats_constructor->IsFunction());
  
    Environment* env = Environment::GetCurrent(args.GetIsolate());
    env->set_fs_stats_constructor_function(stats_constructor);
  }
  
  void InitFs(Handle<Object> target,
              Handle<Value> unused,
              Handle<Context> context,
              void* priv) {
    Environment* env = Environment::GetCurrent(context);
  
    // Function which creates a new Stats object.
    target->Set(
        FIXED_ONE_BYTE_STRING(env->isolate(), "FSInitialize"),
        FunctionTemplate::New(env->isolate(), FSInitialize)->GetFunction());
  
    NODE_SET_METHOD(target, "close", Close);
    NODE_SET_METHOD(target, "open", Open);
    NODE_SET_METHOD(target, "read", Read);
    NODE_SET_METHOD(target, "fdatasync", Fdatasync);
    NODE_SET_METHOD(target, "fsync", Fsync);
    NODE_SET_METHOD(target, "rename", Rename);
    NODE_SET_METHOD(target, "ftruncate", FTruncate);
    NODE_SET_METHOD(target, "rmdir", RMDir);
    NODE_SET_METHOD(target, "mkdir", MKDir);
    NODE_SET_METHOD(target, "readdir", ReadDir);
    NODE_SET_METHOD(target, "stat", Stat);
    NODE_SET_METHOD(target, "statNoException", StatNoException);
    NODE_SET_METHOD(target, "lstatNoException", LStatNoException);
    NODE_SET_METHOD(target, "lstat", LStat);
    NODE_SET_METHOD(target, "fstat", FStat);
    NODE_SET_METHOD(target, "link", Link);
    NODE_SET_METHOD(target, "symlink", Symlink);
    NODE_SET_METHOD(target, "readlink", ReadLink);
    NODE_SET_METHOD(target, "unlink", Unlink);
    NODE_SET_METHOD(target, "writeBuffer", WriteBuffer);
    NODE_SET_METHOD(target, "writeString", WriteString);
  
    NODE_SET_METHOD(target, "chmod", Chmod);
    NODE_SET_METHOD(target, "fchmod", FChmod);
    // NODE_SET_METHOD(target, "lchmod", LChmod);
  
    NODE_SET_METHOD(target, "chown", Chown);
    NODE_SET_METHOD(target, "fchown", FChown);
    // NODE_SET_METHOD(target, "lchown", LChown);
  
    NODE_SET_METHOD(target, "utimes", UTimes);
    NODE_SET_METHOD(target, "futimes", FUTimes);
  
    StatWatcher::Initialize(env, target);
  }
  
  }  // end namespace node
  
  NODE_MODULE_CONTEXT_AWARE_BUILTIN(fs, node::InitFs)
  