I'm very fond of using Node. JS development, But when it comes to compute-intensive scenarios, Node. JS is not very well Qualified. And in this case C + + is a good choice, very fortunate that Node. JS officially provides a mechanism for c/+ + Addons that allows us to use the V8 API to combine Node. JS with C + +.While there are a lot of documents on how to use these APIs on the Node. JS website, It's a hassle to pass data between JavaScript and C + +
The translator presses: I first translation foreign language, the speech unavoidably some obscure, but as far as possible expressed the author's original intention, does not have the excessive polishing, welcome criticizes the correction. Another text is long, the information is big, may be difficult to digest, welcome the message to discuss the detail question. This article focuses on the performance optimization of V8, some content does not apply to
extension
Var notification = new every Y. notification ();
Notification. title = "Notification title ";
Notification. icon = "emblem-default"; // see/usr/share/icons/gnome/16x16
Notification. send ("Notification message ");
Compile our Node. js Extension
Init Method
To create a Node. js extension, we need to write a C ++ class that inherits node: ObjectWrap. ObjectWrap makes it easier for us to interact with Javascript.
Let's first write the basic framework of the class:
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";notification.icon = "emblem-default"; // see /usr/share/icons/gnome/16x16notification.send("Notification message");
Compile our Node. js ExtensionInit Method
To create a Node. js extension, we need to write a C ++ class that inherits node: ObjectWrap. ObjectWrap makes it easier for us to interact with Javascript.
Let's first write the basic framework of the class:
# Include
// V8 is the Javascript engine used by QNode # include
// We
This is a creation in
Article, where the information may have evolved or changed.
File Test.h as follows
#ifndef _test_h#define _test_h#ifdef __cplusplusextern "C" {#endifextern void MyTest (); #ifdef __cplusplus} #endif #endif
File test.cc as follows
#include "_cgo_export.h" extern "C" {void MyTest () {test ();}}
File Test.go as follows
Package test/* #include "test.h" */import "C" import () func test () {c.mytest ()}//export testfunc Test () {println ("Hello")}
If you do go build-x you wi
At the last weekly meeting, the experts introduced some of the new features of android5.0. One of them is the main color extraction, according to the product manager, we'd better add this feature to the next phase of demand. So we started to look at this new feature. This is the new interface placed in the support package, which means that this interface is not related to the Android version. It seems that the source code is not too big. :-)Let's take a look at Google's official notes. Https://d
MailTo part to the system administrator mailbox address, more configuration details can refer to its official http://www.logwatch.org
LogDir = /var/logMailTo = admin@local.comPrint = NoRange = yesterdayDetail = HighService = All
2. Use Swatch for real-time log monitoring
Swatch download link for http://sourceforge.net/projects/swatch/ to install
Write high-performance JavaScript
Translator's note: I translated foreign languages for the first time, and the words are difficult to understand. However, I tried to express the author's original intention as much as possible. without too much polishing, I welcome criticism and correction. In addition, this article is long and informative, which may be difficult to digest. You are welcome to leave a message to discuss the details. This article focuses on V8
This article mainly introduces Node. three implementation methods of js writing components, including pure js implementation, v8API implementation (synchronous amp; asynchronous), and implementation using the swig framework, if you are interested, refer to the following: first, we will introduce the differences between using v8 APIs and using swig frameworks:
(1) v8 API is an official native method with p
://www.logwatch.org.
LogDir =/var/log
MallTo = admin@local.com
Pnnt = No
Range = yesterday
Detail = High
Service = All
2. Use Swatch for real-time log monitoring
The download link of Swatch is http://sourceforge.net/projects/swatch /. To install Swatch, you must first install two perl module packages: date0000calc00005
Here's a photo of the source I want to use to collect colors, and I want to create a set of color samples called "Autumn Leaves".
Step 1: Remove the extra swatches in the Photoshop swatches panel
To better capture the color, we need to first remove the extra swatches. Don't worry about the color swatch being permanently deleted because the default swatch for PS is ready to be restored.
. Listing 1 Listing 1 shows an example of a recommended HTML template for JQuery Mobile, which is used for each of the main elements data-role .Listing 1. An element that uses page Data-roleAnother very important and recommendable element is the tag. This tag specifies how a browser should display the mobile site. The following code shows how to add a tag to set up a mobile device viewport :Tags are important for rendering the page properly based on a device that accesses a mobile Web page. Wi
Due to memory leakage in Node. javascript is very common. It may not be particularly sensitive to its memory leakage when using javascript in a browser, but you have to consider these issues when running as a server language. The previous Chance was that when react was rendered on the server, it was NODE_ENV! = Production will cause memory leakage. Specific issues: https://github.com/facebook/react/issues/7406. With the widespread use of technologies such as node and react, node memory leaks and
anotherLargeObject = LargeObject.fromSize('100MB'); return function() { largeObject.work(); console.log('inner'); };}var inner = outer();
The first obvious concept is:largeObjectCannot be recycledBecauseinnerYou must use it. HoweveranotherLargeObjectCan it be recycled? It will followlargeObjectAlways exist together, orlargeObjectIsolated and independently recycled?Test Method
With this question, we have tested several existing modern javascript Engines, including:
JScript.
Zookeeper
The previous article introduced the encoding section in the Node. js C ++ module. Before that, I would like to list some information in this area for your reference.
V8 Data Structure Manual
Node C ++ module entry
Understanding node from the perspective of C ++
(Google Baidu, these materials can guide us to write a complete Node. js C ++ extension. However, the following content may make the writing process easier .)
First, let's understan
A previous chance found that react when the server renders, when node_env!= production, it can cause a memory leak. Concrete issues:https://github.com/facebook/react/issues/7406. With the node,react isomorphism and other technology widely used, node-side memory leakage and other problems should arouse our attention. Why node is prone to memory leaks and how to troubleshoot them after they appear, here is a simple introduction and examples to illustrate.
First, node is based on the
, what is the current mainstream browser about sorting? Next, we compare Chrome,Firefox , and Microsoft Edgeto each other.
The implementation in Chrome
The Chrome JavaScript engine is V8. Because it is open source, you can see the source code directly.
The entire array.js is implemented in JavaScript language. The Sorting Method section is obviously much more complex than the quick sort you've seen before, but it's clear that the core algorithm is
NativescriptNativescript is a running environment that allows you to use generic JavaScript code to create native Ios,android and Windows (upcoming) applications. Nativescript has a number of cool features, such as supporting JavaScript object bidirectional binding to native UI components, and using CSS to write styles for native applications. But my favorite feature is that Nativescript gives you direct access to native APIs on the local platform.Note * It can be understood that Nativescript is
;adjvex;// the vertex adjacent to the vertexpnode=pnode->next;//the next connected edge of the vertexif (visited[j]==1)// Whether the vertex has been accessedcontinue;// has visitedDFS (PG,J);// not accessed, recursive call accesses its adjacency vertex}}int main (int argc, char* argv[]){printf ("depth-first search algorithm for adjacency table storage structure \ n");Adjlist ag;//non-direction diagramag.vexnum=9;Ag.adjlist[0].data= "V0";Ag.adjlist[1].data= "V1"; Ag.adjlist[2].data= "V2";Ag.adjl
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