node/src/node_stat_watcher.cc

// 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_stat_watcher.h"

#include <assert.h>
#include <string.h>
#include <stdlib.h>

// Poll interval in milliseconds. 5007 is what libev used to use. It's a little
// on the slow side but let's stick with it for now, keep behavioral changes to
// a minimum.
#define DEFAULT_POLL_INTERVAL 5007

namespace node {

using namespace v8;

Persistent<FunctionTemplate> StatWatcher::constructor_template;
static Persistent<String> onchange_sym;
static Persistent<String> onstop_sym;


void StatWatcher::Initialize(Handle<Object> target) {
  HandleScope scope;

  Local<FunctionTemplate> t = FunctionTemplate::New(StatWatcher::New);
  constructor_template = Persistent<FunctionTemplate>::New(t);
  constructor_template->InstanceTemplate()->SetInternalFieldCount(1);
  constructor_template->SetClassName(String::NewSymbol("StatWatcher"));

  NODE_SET_PROTOTYPE_METHOD(constructor_template, "start", StatWatcher::Start);
  NODE_SET_PROTOTYPE_METHOD(constructor_template, "stop", StatWatcher::Stop);

  target->Set(String::NewSymbol("StatWatcher"), constructor_template->GetFunction());
}


void StatWatcher::Callback(uv_fs_poll_t* handle,
                           int status,
                           const uv_statbuf_t* prev,
                           const uv_statbuf_t* curr) {
  StatWatcher* wrap = container_of(handle, StatWatcher, watcher_);
  assert(handle == &wrap->watcher_);
  HandleScope scope;
  Local<Value> argv[3];
  argv[0] = BuildStatsObject(curr);
  argv[1] = BuildStatsObject(prev);
  argv[2] = Integer::New(status);
  if (status == -1) {
    SetErrno(uv_last_error(wrap->watcher_.loop));
  }
  if (onchange_sym.IsEmpty()) {
    onchange_sym = NODE_PSYMBOL("onchange");
  }
  MakeCallback(wrap->handle_, onchange_sym, ARRAY_SIZE(argv), argv);
}


Handle<Value> StatWatcher::New(const Arguments& args) {
  if (!args.IsConstructCall()) {
    return FromConstructorTemplate(constructor_template, args);
  }

  HandleScope scope;
  StatWatcher* s = new StatWatcher();
  s->Wrap(args.Holder());
  return args.This();
}


Handle<Value> StatWatcher::Start(const Arguments& args) {
  HandleScope scope;

  if (args.Length() < 1 || !args[0]->IsString()) {
    return ThrowException(Exception::TypeError(String::New("Bad arguments")));
  }

  StatWatcher* wrap = ObjectWrap::Unwrap<StatWatcher>(args.Holder());
  String::Utf8Value path(args[0]);

  uint32_t interval = DEFAULT_POLL_INTERVAL;
  if (args[2]->IsUint32()) {
    interval = args[2]->Uint32Value();
  }

  uv_fs_poll_start(&wrap->watcher_, Callback, *path, interval);

  wrap->persistent_ = args[1]->IsTrue();

  if (!wrap->persistent_) {
    uv_unref(reinterpret_cast<uv_handle_t*>(&wrap->watcher_));
  }

  wrap->Ref();

  return Undefined();
}


Handle<Value> StatWatcher::Stop(const Arguments& args) {
  HandleScope scope;
  StatWatcher* wrap = ObjectWrap::Unwrap<StatWatcher>(args.Holder());
  if (onstop_sym.IsEmpty()) {
    onstop_sym = NODE_PSYMBOL("onstop");
  }
  MakeCallback(wrap->handle_, onstop_sym, 0, NULL);
  wrap->Stop();
  return Undefined();
}


void StatWatcher::Stop () {
  if (!uv_is_active(reinterpret_cast<uv_handle_t*>(&watcher_))) return;
  uv_fs_poll_stop(&watcher_);
  Unref();
}


}  // namespace node