在C++中嵌入JavaScript——Google V8 JavaScript Engine使用体验
在C++中嵌入JavaScript——Google V8 JavaScript Engine使用体验
Google V8 Script Engine 使用体验
Google V8 JavaScript Engine是google为 Chrome's浏览器开发的脚本引擎，现在可以使用V8 JavaScript Engine在C++程序中建立自己的脚本环境。
1.准备工作
1). 安装一个SVN客户端 http://tortoisesvn.net/downloads，google v8 在官方网站仅以此方式发布；
2).下载一个python:地址http://sourceforge.net/projects/pywin32/files/，官方网站2009年10月15日被墙了
2.checkout并准备环境
0)设置目录：
+third_party
+python_24 Python位置（拷贝或安装到均可）
+V8 V8 check out 位置
1)安装python
---------------------------------------begin-------------------------------------------------
说明:
由于v8.project在配置时，使用如下命令进行处理:
.\d8js2c.cmd ..\..\src "$(IntDir)\DerivedSources"
其中: d8js2c.cmd(line4)： set PYTHON="..\..\..\third_party\python_24\python.exe"
显然python和相关库应该位于：..\..\..\third_party\python_24\
---------------------------------------end---------------------------------------------------
2)下载 Google V8 Script Engine下载，
SVN地址： http://code.google.com/p/v8/source/checkout
3)编译
V8\tools\visual_studio\v8.sln
这样就可以编译了，如果编译失败，那可能就是python没有配置好。
3. JS 嵌入C++示例代码
一个Hello world!
#include
"
http://www.cnblogs.com/include/v8.h
"
#pragma
comment(lib,"../visual_studio/Release/lib/v8.lib")
#pragma
comment(lib,"../visual_studio/Release/lib/v8_base.lib")
using
namespace
v8;
int
main(
int
argc,
char
*
argv[]) {
//
Create a stack-allocated handle scope.
HandleScope handle_scope;
//
Create a new context.
Persistent
<
Context
>
context
=
Context::New();
//
Enter the created context for compiling and
//
running the hello world script.
Context::Scope context_scope(context);
//
Create a string containing the JavaScript source code.
Handle
<
String
>
source
=
String::New(
"
'Hello' + ', World!'
"
);
//
Compile the source code.
Handle
<
Script
>
script
=
Script::Compile(source);
//
Run the script to get the result.
Handle
<
Value
>
result
=
script
->
Run();
//
Dispose the persistent context.
context.Dispose();
//
Convert the result to an ASCII string and print it.
String::AsciiValue ascii(result); printf(
"
%s\n
"
,
*
ascii);
return
0
; }
更多示例代码参考：V8\test\cctest\*.cc
4.支持C++类
CProxyV8提供便利的方式将C++类的属性和方法导出到JavaScript环境中。支持generic Functors，不需要为每个属性和方法设置回调函数。
class
Point {
public
:
/*
* Constructor without params is required
*/
Point(
int
px
=
0
,
int
py
=
0
) : x_(px), y_(py) {} Point(Point
*
p) : x_(p
->
x_), y_(p
->
y_) {}
int
x_;
int
y_;
/*
* Example call to function without params
*/
int
GetManhattanLength() {
return
std::abs(x_)
-
std::abs(y_); }
/*
* this will create a JS object, with JS destructor
*/
Point
*
Copy() {
return
new
Point(); }
/*
* Example call to function with params
*/
v8::Handle
<
v8::Value
>
Translate(
const
v8::Arguments
&
args) {
//
throw if we didn't get 2 args
if
(args.Length()
!=
2
)
return
ThrowException(v8::String::New(
"
Expected 2 arguments
"
)); x_
+=
args[
0
]
->
Int32Value(); y_
+=
args[
1
]
->
Int32Value();
return
v8::True(); }; };
class
Line {
public
:
/*
* Constructor without params is required
*/
/*
* Example of object property, it can be manipulate directly
*/
Point start;
/*
* this will create a JS object, without destructor and a reference to this * end instance *
*/
Point
&
GetEnd() {
return
end; }
private
: Point end; };
int
main(
int
argc,
char
*
argv[]) { v8::V8::SetFlagsFromCommandLine(
&
argc, argv,
true
); v8::HandleScope handle_scope;
//
Create a template for the global object.
v8::Handle
<
v8::ObjectTemplate
>
global
=
v8::ObjectTemplate::New(); ProxyClass
<
Foo
>*
pPoint
=
ProxyClass
<
Foo
>
::instance();
//
Get the proxy class for Point
pPoint
->
Expose(
&
Point::x_,
"
x
"
,
true
,
true
);
//
expose x_ for read/write
pPoint
->
Expose(
&
Point::y_,
"
y
"
,
true
,
true
);
//
expose y_ for read/write
pPoint
->
Expose(
&
Point::Copy,
"
copy
"
); pPoint
->
Expose(
&
Point::GetManhattanLength,
"
getManhattanLength
"
); pPoint
->
Expose(
&
Point::Translate,
"
translate
"
); ProxyClass
<
Line
>*
pLine
=
ProxyClass
<
Line
>
::instance();
//
Get the proxy class for Line
pPoint
->
Expose(
&
Line::start,
"
start
"
,
true
,
true
);
//
expose object start for read/write
pPoint
->
Expose(
&
Line::GetEnd,
"
getEnd
"
);
global
->
Set(v8::String::New(
"
Point
"
), pPoint
->
GetFunctionTemplate());
//
add Point to JS
global
->
Set(v8::String::New(
"
Line
"
), pLine
->
GetFunctionTemplate());
//
add Line to JS
...
如果借助宏，就较简单：
int
main(
int
argc,
char
*
argv[]) { v8::V8::SetFlagsFromCommandLine(
&
argc, argv,
true
); v8::HandleScope handle_scope;
//
Create a template for the global object.
v8::Handle
<
v8::ObjectTemplate
>
global
=
v8::ObjectTemplate::New(); CPROXYV8_PROPERTY_ID(Point,x_,x,
true
,
true
); CPROXYV8_PROPERTY_ID(Point,y_,y,
true
,
true
); CPROXYV8_METHOD_ID(Point,Copy, copy); CPROXYV8_METHOD_ID(Point,GetManhattanLength, getManhattanLength); CPROXYV8_METHOD(Point,Translate); CPROXYV8_PROPERTY(Line,start,
true
,
true
); CPROXYV8_METHOD_ID(Line,GetEnd,getEnd);
global
->
Set(v8::String::New(
"
Point
"
), CPROXYV8_CLASS(Point)
->
GetFunctionTemplate());
//
add Point to JS
global
->
Set(v8::String::New(
"
Line
"
), CPROXYV8_CLASS(Line)
->
GetFunctionTemplate());
//
add Line to JS
在Shell中使用这些类：
V8 version
0.4
.
3.1
>
x
=
new
Point() [object Point]
>
line
=
new
Line() [object Line]
>
x.x
0
>
x.x
=
10
10
>
line.getEnd().x
0
>
line.getEnd().x
=
10
10
>
line.getEnd().x
10
>
end
=
line.getEnd(); [object Point]
>
end.x
10
>
end.Translate(
10
,
10
)
true
>
end.x
20
>
line.getEnd().x
20
>
x.x
10
>
_
官方网站:
http://code.google.com/p/v8/
http://code.google.com/p/cproxyv8/