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标题: 功能强大的JavaScript引擎--SpiderMonkey程序样例 [打印本页]

作者: look_w 时间: 2018-4-15 18:41 标题: 功能强大的JavaScript引擎--SpiderMonkey程序样例

程序样例以下是一个简单的样例程序，它从文件test.js中读入一段脚本，然后解释执行并输出结果。脚本中可嵌入自定义对象People，People对象具有属性name(表示该人的姓名)、address（表示该人的地址）及方法print（在屏幕上显示该人的姓名、地址信息）。
例如：下面是一段简单的js脚本，它首先利用print方法输出该人的姓名和地址，然后将姓名和地址分别修改为John和Beijing，最后再次输出其姓名和地址，看是否修改正确。
people.print();
people.name="John";
people.address="Beijing";
people.print();
下面是C源程序代码。

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#include "js.h"
enum tagMY_PEOPLE {MY_NAME,MY_ADDRESS};
static JSBool GetPeopleProperty (JSContext *cx, JSObject *obj, jsval id, jsval *vp);
static JSBool SetPeopleProperty (JSContext *cx, JSObject *obj, jsval id, jsval *vp);
static JSBool PeoplePrint(JSContext *cx, JSObject *obj, uintN argc,
      jsval *argv, jsval *rval);
typedef struct{
char name[16];
char addr[64];}PeopleInfo;
static PeopleInfo m_ainfo={"myName","myAddress"};
/*定义属性的 GETTER*/
static JSBool GetPeopleProperty (JSContext *cx, JSObject *obj, jsval id, jsval *vp)
{
if (JSVAL_IS_INT(id)) {
      switch (JSVAL_TO_INT(id)) {
         case MY_NAME:
            *vp=STRING_TO_JSVAL (JS_NewStringCopyZ (cx,m_ainfo.name));
            break;
         case MY_ADDRESS:
            *vp=STRING_TO_JSVAL (JS_NewStringCopyZ (cx,m_ainfo.addr));
            break;
         }
}
return JS_TRUE;
}
/*定义属性的SETTER*/
static JSBool SetPeopleProperty (JSContext *cx, JSObject *obj, jsval id, jsval *vp)
{
if (JSVAL_IS_INT(id)) {
      switch (JSVAL_TO_INT(id)) {
         case MY_NAME:
            strncpy (m_ainfo.name, JS_GetStringBytes (jss), 15);
            break;
         case MY_ADDRESS:
            strncpy (m_ainfo.addr, JS_GetStringBytes (jss), 63);
            break;
         }
}
return JS_TRUE;
}
/*定义print方法*/
static JSBool PeoplePrint(JSContext *cx, JSObject *obj, uintN argc, jsval *argv,
jsval *rval)
{
fprintf(stdout,"My Name is %s.\nMy Addr is %s.\n",m_ainfo.name,m_ainfo.addr);
return JS_TRUE;
}
void main()
{
JSString* jss;
char buf[5120];
int len;
jsval rval;
JSRuntime *rt;
JSContext *cx;
JSObject *globalObj,*PeopleObj;
JSClass global_class = {
         "global",0,
         JS_PropertyStub, JS_PropertyStub,JS_PropertyStub, JS_PropertyStub,
         JS_EnumerateStub, JS_ResolveStub,JS_ConvertStub, JS_FinalizeStub };
/*定义People类的属性数组*/
static JSPropertySpec PeopleProperties[] =
  {
{"name", MY_NAME, JSPROP_ENUMERATE },
{"address",  MY_ADDRESS,    JSPROP_ENUMERATE },
{0}
  } ;
/*定义People类的方法数组*/
static JSFunctionSpec PeopleMethods[] =
{
{"print",       PeoplePrint,    0},
         {0}
      };
/*定义People类*/
static JSClass PeopleClass = {
      "people",0,
  JS_PropertyStub,JS_PropertyStub, GetPeopleProperty, SetPeopleProperty,
  JS_EnumerateStub, JS_ResolveStub, JS_ConvertStub, JS_FinalizeStub
};
typedef struct{}
   /* 初始化JS RunTime，返回结果给rt */
rt = JS_Init(1000000L);
if (!rt)return;
  /* 创建一个上下文，并将其与JS RunTime关联起来 */
cx = JS_NewContext(rt, 5120);
if (!cx)return;
  /* 创建全局对象 */
if (!(globalObj = JS_NewObject (cx, &global_class, NULL, NULL)))return;
   /* 实例化内置对象和全局对象*/
JS_InitStandardClasses (cx, globalObj);
/*实例化People对象*/
PeopleObj = JS_DefineObject (cx, globalObj, "People", &PeopleClass, 0,JSPROP_ENUMERATE);
/*创建对象的属性*/
JS_DefineProperties (cx,PeopleObj, PeopleProperties);
/*创建对象的方法*/
JS_DefineFunctions (cx,PeopleObj, PeopleMethods);
FILE* fp;
/*打开文件，读入脚本*/
if (!(fp = fopen ("test.js", "r")))return;
len = fread (buf, 1, 5120, fp);
fclose (fp);
if (len <= 0)return;
/*执行一段脚本*/
JS_EvaluateScript (cx, globalObj, buf, len, "", 1, &rval);
jss = JS_ValueToString (cx, rval);
fprintf(stdout，"The result is: %s"，JS_GetStringBytes (jss));
/*释放上下文*/
JS_DestroyContext(cx);
/*释放RunTime*/
JS_DestroyRuntime(rt);
return;
}

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