《HTML 5网页开发实例详解》源码2

Native Abstractions for Node.js =============================== **A header file filled with macro and utility goodness for making addon development for Node.js easier across versions 0.8, 0.10 and 0.11, and eventually 0.12.** ***Current version: 0.3.2*** *(See [nan.h](https://github.com/rvagg/nan/blob/master/nan.h) for changelog)* [](https://nodei.co/npm/nan/) [](https://nodei.co/npm/nan/) Thanks to the crazy changes in V8 (and some in Node core), keeping native addons compiling happily across versions, particularly 0.10 to 0.11/0.12, is a minor nightmare. The goal of this project is to store all logic necessary to develop native Node.js addons without having to inspect `NODE_MODULE_VERSION` and get yourself into a macro-tangle. This project also contains some helper utilities that make addon development a bit more pleasant. * **[Usage](#usage)** * **[Example](#example)** * **[API](#api)** <a name="usage"></a> ## Usage Simply add **NAN** as a dependency in the *package.json* of your Node addon: ```js "dependencies": { ... "nan" : "~0.3.1" ... } ``` Pull in the path to **NAN** in your *binding.gyp* so that you can use `#include "nan.h"` in your *.cpp*: ```js "include_dirs" : [ ... "<!(node -p -e \"require('path').dirname(require.resolve('nan'))\")" ... ] ``` This works like a `-I<path-to-NAN>` when compiling your addon. <a name="example"></a> ## Example See **[LevelDOWN](https://github.com/rvagg/node-leveldown/pull/48)** for a full example of **NAN** in use. For a simpler example, see the **[async pi estimation example](https://github.com/rvagg/nan/tree/master/examples/async_pi_estimate)** in the examples directory for full code and an explanation of what this Monte Carlo Pi estimation example does. Below are just some parts of the full example that illustrate the use of **NAN**. Compare to the current 0.10 version of this example, found in the [node-addon-examples](https://github.com/rvagg/node-addon-examples/tree/master/9_async_work) repository and also a 0.11 version of the same found [here](https://github.com/kkoopa/node-addon-examples/tree/5c01f58fc993377a567812597e54a83af69686d7/9_async_work). Note that there is no embedded version sniffing going on here and also the async work is made much simpler, see below for details on the `NanAsyncWorker` class. ```c++ // addon.cc #include <node.h> #include "nan.h" // ... using namespace v8; void InitAll(Handle<Object> exports) { exports->Set(NanSymbol("calculateSync"), FunctionTemplate::New(CalculateSync)->GetFunction()); exports->Set(NanSymbol("calculateAsync"), FunctionTemplate::New(CalculateAsync)->GetFunction()); } NODE_MODULE(addon, InitAll) ``` ```c++ // sync.h #include <node.h> #include "nan.h" NAN_METHOD(CalculateSync); ``` ```c++ // sync.cc #include <node.h> #include "nan.h" #include "sync.h" // ... using namespace v8; // Simple synchronous access to the `Estimate()` function NAN_METHOD(CalculateSync) { NanScope(); // expect a number as the first argument int points = args[0]->Uint32Value(); double est = Estimate(points); NanReturnValue(Number::New(est)); } ``` ```c++ // async.cc #include <node.h> #include "nan.h" #include "async.h" // ... using namespace v8; class PiWorker : public NanAsyncWorker { public: PiWorker(NanCallback *callback, int points) : NanAsyncWorker(callback), points(points) {} ~PiWorker() {} // Executed inside the worker-thread. // It is not safe to access V8, or V8 data structures // here, so everything we need for input and output // should go on `this`. void Execute () { estimate = Estimate(points); } // Executed when the async work is complete // this function will be run inside the main event loop // so it is safe to use V8 again void HandleOKCallback () { NanScope(); Local<Value> argv[] = { Local<Value>::New(Null()) , Number::New(estimate) }; callback->Call(2, argv); }; private: int points; double estimate; }; // Asynchronous access to the `Estimate()` function NAN_METHOD(CalculateAsync) { NanScope(); int points = args[0]->Uint32Value(); NanCallback *callback = new NanCallback(args[1].As<Function>()); NanAsyncQueueWorker(new PiWorker(callback, points)); NanReturnUndefined(); } ``` <a name="api"></a> ## API * <a href="#api_nan_method"><b><code>NAN_METHOD</code></b></a> * <a href="#api_nan_getter"><b><code>NAN_GETTER</code></b></a> * <a href="#api_nan_setter"><b><code>NAN_SETTER</code></b></a> * <a href="#api_nan_property_getter"><b><code>NAN_PROPERTY_GETTER</code></b></a> * <a href="#api_nan_property_setter"><b><code>NAN_PROPERTY_SETTER</code></b></a> * <a href="#api_nan_property_enumerator"><b><code>NAN_PROPERTY_ENUMERATOR</code></b></a> * <a href="#api_nan_property_deleter"><b><code>NAN_PROPERTY_DELETER</code></b></a> * <a href="#api_nan_property_query"><b><code>NAN_PROPERTY_QUERY</code></b></a> * <a href="#api_nan_weak_callback"><b><code>NAN_WEAK_CALLBACK</code></b></a> * <a href="#api_nan_return_value"><b><code>NanReturnValue</code></b></a> * <a href="#api_nan_return_undefined"><b><code>NanReturnUndefined</code></b></a> * <a href="#api_nan_return_null"><b><code>NanReturnNull</code></b></a> * <a href="#api_nan_return_empty_string"><b><code>NanReturnEmptyString</code></b></a> * <a href="#api_nan_scope"><b><code>NanScope</code></b></a> * <a href="#api_nan_locker"><b><code>NanLocker</code></b></a> * <a href="#api_nan_unlocker"><b><code>NanUnlocker</code></b></a> * <a href="#api_nan_get_internal_field_pointer"><b><code>NanGetInternalFieldPointer</code></b></a> * <a href="#api_nan_set_internal_field_pointer"><b><code>NanSetInternalFieldPointer</code></b></a> * <a href="#api_nan_object_wrap_handle"><b><code>NanObjectWrapHandle</code></b></a> * <a href="#api_nan_make_weak"><b><code>NanMakeWeak</code></b></a> * <a href="#api_nan_symbol"><b><code>NanSymbol</code></b></a> * <a href="#api_nan_get_pointer_safe"><b><code>NanGetPointerSafe</code></b></a> * <a href="#api_nan_set_pointer_safe"><b><code>NanSetPointerSafe</code></b></a> * <a href="#api_nan_from_v8_string"><b><code>NanFromV8String</code></b></a> * <a href="#api_nan_boolean_option_value"><b><code>NanBooleanOptionValue</code></b></a> * <a href="#api_nan_uint32_option_value"><b><code>NanUInt32OptionValue</code></b></a> * <a href="#api_nan_throw_error"><b><code>NanThrowError</code></b>, <b><code>NanThrowTypeError</code></b>, <b><code>NanThrowRangeError</code></b>, <b><code>NanThrowError(Handle<Value>)</code></b>, <b><code>NanThrowError(Handle<Value>, int)</code></b></a> * <a href="#api_nan_new_buffer_handle"><b><code>NanNewBufferHandle(char *, size_t, FreeCallback, void *)</code></b>, <b><code>NanNewBufferHandle(char *, uint32_t)</code></b>, <b><code>NanNewBufferHandle(uint32_t)</code></b></a> * <a href="#api_nan_buffer_use"><b><code>NanBufferUse(char *, uint32_t)</code></b></a> * <a href="#api_nan_new_context_handle"><b><code>NanNewContextHandle</code></b></a> * <a href="#api_nan_has_instance"><b><code>NanHasInstance</code></b></a> * <a href="#api_nan_persistent_to_local"><b><code>NanPersistentToLocal</code></b></a> * <a href="#api_nan_dispose"><b><code>NanDispose</code></b></a> * <a href="#api_nan_assign_persistent"><b><code>NanAssignPersistent</code></b></a> * <a href="#api_nan_init_persistent"><b><code>NanInitPersistent</code></b></a> * <a href="#api_nan_callback"><b><code>NanCallback</code></b></a> * <a href="#api_nan_async_worker"><b><code>NanAsyncWorker</code></b></a> * <a href="#api_nan_async_queue_worker"><b><code>NanAsyncQueueWorker</code></b></a> <a name="api_nan_method"></a> ### NAN_METHOD(methodname) Use `NAN_METHOD` to define your V8 accessible methods: ```c++ // .h: class Foo : public node::ObjectWrap { ... static NAN_METHOD(Bar); static NAN_METHOD(Baz); } // .cc: NAN_METHOD(Foo::Bar)