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背景：我正在尝试创建一个 node.js 克隆用于演示目的和作为学习练习。

尝试调用我已从 c++ 附加到 javascript 中的对象的回调时，我遇到了段错误。我正在使用obj->Set(xxx, callback). 每当发生 http 请求时，我都会返回该对象并使用该对象obj->Get(xxx)获取该回调并尝试调用它。但是，我在使用指针时遇到了段错误。

这是代码：

#include "HttpWrap.h"
#include <cstdlib>
#include "v8/include/v8.h"
#include "libuv/include/uv.h"

using namespace v8;

HttpWrap::HttpWrap(const Arguments& args)
{
   Local<ObjectTemplate> serverTemplate = ObjectTemplate::New();
   serverTemplate->SetInternalFieldCount(1);
   serverTemplate->Set(String::New("listen"), FunctionTemplate::New(Listen));

   Local<Object> localServer = serverTemplate->NewInstance();
   localServer->SetInternalField(0, External::New(this));

   String::AsciiValue ip_address(args[0]);
   int port = args[1]->Int32Value();

   handle = (uv_tcp_t*) malloc(sizeof(uv_tcp_t));
   uv_tcp_init(uv_default_loop(), handle);
   handle->data = this;
   uv_tcp_bind(handle, uv_ip4_addr(*ip_address, port));

   server = Persistent<Object>::New(localServer);
}

Handle<Value> HttpWrap::Listen(const Arguments& args)
{
   puts("HttpWrap::Listen");

   HandleScope scope;

   Local<External> wrap = Local<External>::Cast(args.Holder()->GetInternalField(0));
   HttpWrap* httpWrap = static_cast<HttpWrap*>(wrap->Value());
   httpWrap->server->Set(String::New("onrequest"), args[0]);
   uv_listen((uv_stream_t*) httpWrap->handle, 128, OnConnection);

   return scope.Close(Undefined());
}

void HttpWrap::OnConnection(uv_stream_t* handle, int status)
{
   puts("HttpWrap::OnConnection");
   uv_tcp_t* client = (uv_tcp_t*) malloc(sizeof(uv_tcp_t));
   uv_tcp_init(uv_default_loop(), client);
   client->data = handle->data;
   uv_accept(handle, (uv_stream_t*) client);
   uv_read_start((uv_stream_t*) client, AllocConnection, OnRead);
}

uv_buf_t HttpWrap::AllocConnection(uv_handle_t* handle, size_t suggested_size)
{
   puts("HttpWrap::AllocConnection");
   return uv_buf_init((char*) malloc(suggested_size), suggested_size);
}

void HttpWrap::OnRead(uv_stream_t* server, ssize_t nread, uv_buf_t buf)
{
   HandleScope scope;
   puts("HttpWrap::OnRead");

   HttpWrap* httpWrap = static_cast<HttpWrap*>(server->data);
   Local<String> callbackSym = String::New("onrequest");
   Local<Value> value = httpWrap->server->Get(callbackSym);

   if (!value->IsFunction())
   {
      puts("Value is not a function");
   }
   else 
   {
      puts("Value is a function");
      Local<Function> callback = Local<Function>::Cast(value);
      Local<Value>* argv = new Local<Value>[1];
      argv[0] = String::New("test");
      puts("Invoking callback");
      callback->Call(Context::GetCurrent()->Global(), 1, argv);
      puts("invoked callback");
   }

   free(buf.base);
   uv_close((uv_handle_t*) server, OnClose);
}

void HttpWrap::OnClose(uv_handle_t* handle)
{
   puts("HttpWrap::OnClose");
}

也可以在 Github 上找到。

感兴趣的行是 36 和 65。每当尝试调用callback->Call.

非常感谢您提出的任何想法或良好做法！

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1 回答 1

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不幸的是，在解决这个问题时，我有点狭隘。主要问题是我在尝试调用回调之前处理了主要上下文。由于上下文被处理，试图调用 js 空间中的代码失败。

于 2012-07-16T04:26:13.173 回答