testInt32ToId.js (1208B)
1 function testInt32ToId() 2 { 3 // Ensure that a property which is a negative integer that does not fit in a 4 // jsval is properly detected by the 'in' operator. 5 var obj = { "-1073741828": 17 }; 6 var index = -1073741819; 7 var a = []; 8 for (var i = 0; i < 10; i++) 9 { 10 a.push(index in obj); 11 index--; 12 } 13 14 // Ensure that a property which is a negative integer that does not fit in a 15 // jsval is properly *not* detected by the 'in' operator. In this case 16 // wrongly applying INT_TO_JSID to -2147483648 will shift off the sign bit 17 // (the only bit set in that number) and bitwise-or that value with 1, 18 // producing jsid(1) -- which actually represents "0", not "-2147483648". 19 // Thus 'in' will report a "-2147483648" property when none exists, because 20 // it thinks the request was really whether the object had property "0". 21 var obj2 = { 0: 17 }; 22 var b = []; 23 var index = -(1 << 28); 24 for (var i = 0; i < 10; i++) 25 { 26 b.push(index in obj2); 27 index = index - (1 << 28); 28 } 29 30 return a.join(",") + b.join(","); 31 } 32 33 assertEq(testInt32ToId(), 34 "false,false,false,false,false,false,false,false,false,true" + 35 "false,false,false,false,false,false,false,false,false,false");