C++调用V8与JS交互

C++访问JS函数

C++部分：

/**
 * COMPILE foo.js AT THE FIRST COMMAND PROMPT TO RUN foo.js
 */


#include <v8.h>
#include <iostream>
#include <fstream>
#include <string>


using namespace v8;
using namespace std;

v8::Handle<v8::String> ReadFile(const char* name);

//*******************************
//        My helpers
//*******************************
/**
* Add[DataType]ToArguments(string/double/bool, Handle<Value>, UINT)
* / [datatype] value to assign to argument list
* / pass in arguments handle
* / position in argument list to
* This function will eaily convert and set the values for an argument list
* to easily pass into a JS function you are calling from C++
* JSEx: Func(arg[0], arg[1], ..)
**/
void AddStringToArguments(std::string str, Handle<Value> argList[], unsigned int argPos){
    argList[argPos] = v8::String::New(str.c_str());
}
void AddNumberToArguments(double num, Handle<Value> argList[], unsigned int argPos){
    argList[argPos] = v8::Number::New(num);
}
void AddBooleanToArguments(bool value, Handle<Value> argList[], unsigned int argPos){
    argList[argPos] = v8::Boolean::New(value);
}
// Examples of these pass in the Isolite instead of global and create global within shell.cc for example line 99
/**
* CallJSFunction(Handle<v8::Object>, string, Handle<Value>, UINT)
* / Handle of the global that is running the script with desired function
* / Title of the JS fuction
* / List of arguments for function
* / Number of agrguments
* Returns the return value of the JS function
**/
Handle<v8::Value> CallJSFunction(Handle<v8::Object> global, std::string funcName, Handle<Value> argList[], unsigned int argCount){
    // Create value for the return of the JS function
    Handle<Value> js_result;
    // Grab JS function out of file
    Handle<v8::Value> value = global->Get(String::New(funcName.c_str()));
    // Cast value to v8::Function
    Handle<v8::Function> func = v8::Handle<v8::Function>::Cast(value);
    // Call function with all set values
    js_result = func->Call(global, argCount, argList);
    // Return value from function
    return js_result;
}

int main()
{
    //Get the default Isolate
    Isolate* isolate = Isolate::GetCurrent();

    //Create a stack allocated handle scope
    HandleScope handle_scope(isolate);

    //Handle<Value> init = Integer::New(x);

    //Create the global template
    Handle<ObjectTemplate> global_template = ObjectTemplate::New();

    //Create a context
    Local<Context> context = Context::New(isolate, NULL, global_template);

    //Set the context scope
    Context::Scope context_scope(context);

    Handle<v8::Object> global = context->Global();

    string file = "foo.js";

    while(true){
        cout << "How many times do you want to run the script? 
" << endl;

        int n; 

        cin >> n;

        cout << "" << endl;

        std::cin.get();

        Handle<String> source = ReadFile(file.c_str());

        if(source.IsEmpty())
        {
            cout << "Error reading file" << endl;
            cout << "Press enter to quit" << endl;
            cin.get();
            return 0;
        }

        //Compile
        Handle<Script> script = Script::Compile(source);
    
        //Run the script and print 
        Handle<Value> result;

        result = script->Run();

        // Once script has ran lets call some Functions!!******************
        // Create handle for arguements
        Handle<Value> args[2];

        // Create arguments to be passed into JS function
        AddStringToArguments("BOSS", args, 0);
        AddNumberToArguments(5.0, args, 1);

        // Call the JS function
        Handle<Value> js_result = CallJSFunction(global, "JSrepeat", args, 2);
        String::AsciiValue ascii2(js_result);
        printf("JSrepeat() returned: %s
", ascii2);

        // Lets try another JS fucntion call!!*****************************
        // This function returns the name "Jimmy" with no parameters
        js_result = CallJSFunction(global, "WhatsMyName", NULL, 0);
        String::AsciiValue ascii3(js_result);
        printf("WhatsMyName() returned: %s
", ascii3);


        String::AsciiValue ascii(result);
        cout << "Script result : " ;
        printf("%s
", *ascii);
    } // End of while

    //Exit program
    cout << "
Test completed.  Press enter to exit program. 
" << endl;
    std::cin.get();
    
    return 0;
}

v8::Handle<String> ReadFile(const char* name)
{
    //Open the file
    FILE* file;
    fopen_s(&file, name, "rb");

    //If there is no file, return an empty string
    if (file == NULL) return v8::Handle<v8::String>();

    //Set the pointer to the end of the file
    fseek(file, 0, SEEK_END);

    //Get the size of file
    int size = ftell(file);

    //Rewind the pointer to the beginning of the stream
    rewind(file);

    //Set up and read into the buffer
    char* chars = new char[size + 1];
    chars[size] = '';
    for (int i = 0 ; i < size;)
    {
        int read = static_cast<int>(fread(&chars[i], 1, size - i, file));
        i += read;
    }

    //Close file
    fclose(file);

    v8::Handle<v8::String> result = v8::String::New(chars, size);
    delete[] chars;
    return result;
}

JS部分：

function test_function() { 
    var match = 0;
    if(arguments[0] == arguments[1]) { 
    match = 1; 
    } 
    return match; 
}

function JSrepeat(name, repeat) { 
    var printthis = "";
    for(var i=0; i < repeat; i++){
        printthis += name;
    }
    return printthis; 
}

function ReturnThis(anything) { 
    return anything; 
}

function WhatsMyName() { 
    return "Jimmy"; 
}