gecko/js/tests/js1_5/extensions/regress-348986.js

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is JavaScript Engine testing utilities.
 *
 * The Initial Developer of the Original Code is
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 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s): Igor Bukanov
 *
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//-----------------------------------------------------------------------------
var bug = 348986;
var summary = 'Recursion check of nested functions';
var actual = 'No Crash';
var expect = 'No Crash';


//-----------------------------------------------------------------------------
test();
//-----------------------------------------------------------------------------

function test()
{
  enterFunc ('test');
  printBugNumber (bug);
  printStatus (summary);
  
// Construct f(){function f(){function f(){...}}} with maximum
// nested function declaration still does not hit recursion limit.

  var deepestFunction;

  var n = findActionMax(function(n) {
    var prefix="function f(){";
    var suffix="}";
    var source = Array(n+1).join(prefix) + Array(n+1).join(suffix);
    try {
      deepestFunction = Function(source);
      return true; 
    } catch (e) {
      if (!(e instanceof InternalError))
			throw e;
      return false; 
    }

  });

  if (n == 0)
    throw "unexpected";

  print("Max nested function leveles:"+n);

  n = findActionMax(function(n) {
    try {
      callAfterConsumingCStack(n, function() {});
      return true;
    } catch (e) {
      if (!(e instanceof InternalError))
			throw e;
      return false;	
    }
  });

  print("Max callAfterConsumingCStack levels:"+n);

// Here n is max possible value when callAfterConsumingCStack(n, emptyFunction)
// does not trigger stackOverflow. Decrease it slightly to give some C stack 
// space for deepestFunction.toSource()
  
  n = Math.max(0, n - 10);
  try {
    var src = callAfterConsumingCStack(n, function() {
      return deepestFunction.toSource();
    });
    throw "Test failed to hit the recursion limit.";
  } catch (e) {
    if (!(e instanceof InternalError))
      throw e;
  }

  print('Done');
  expect = true;
  actual = true;
  reportCompare(expect, true, summary);

  exitFunc ('test');
}

function callAfterConsumingCStack(n, action)
{
  var testObj = { 	
    get propertyWithGetter() {
      if (n == 0)
      return action();
      n--;
      return this.propertyWithGetter;
    }
  };
  return testObj.propertyWithGetter;
}


// Return the maximum positive value of N where action(N) still returns true 
// or 0 if no such value exists.
function findActionMax(action)
{
  var N, next, increase;

  n = 0;
  for (;;) {
    var next = (n == 0 ? 1 : n * 2);
    if (!isFinite(next) || !action(next))
      break;
    n = next;
  }
  if (n == 0)
    return 0;
		
  var increase = n / 2;
  for (;;) {
    var next = n + increase;
    if (next == n)
      break;
    if (isFinite(next) && action(next)) {
      n = next;	
    } else if (increase == 1) {
      break;
    } else {
      increase = increase / 2;
    }		
  }
  return n;
}