Bug 1014581 - Vibration API: clamp vibration lengths and array length to match platform restrictions. r=smaug

dom/base/Navigator.cpp

@@ -792,19 +792,21 @@ Navigator::Vibrate(const nsTArray<uint32_t>& aPattern)
     return false;
   }
 
-  if (aPattern.Length() > sMaxVibrateListLen) {
-    return false;
+  nsTArray<uint32_t> pattern(aPattern);
+
+  if (pattern.Length() > sMaxVibrateListLen) {
+    pattern.SetLength(sMaxVibrateMS);
   }
 
-  for (size_t i = 0; i < aPattern.Length(); ++i) {
-    if (aPattern[i] > sMaxVibrateMS) {
-      return false;
+  for (size_t i = 0; i < pattern.Length(); ++i) {
+    if (pattern[i] > sMaxVibrateMS) {
+      pattern[i] = sMaxVibrateMS;
     }
   }
 
   // The spec says we check sVibratorEnabled after we've done the sanity
   // checking on the pattern.
-  if (aPattern.IsEmpty() || !sVibratorEnabled) {
+  if (pattern.IsEmpty() || !sVibratorEnabled) {
     return true;
   }
 
@@ -822,7 +824,7 @@ Navigator::Vibrate(const nsTArray<uint32_t>& aPattern)
   }
   gVibrateWindowListener = new VibrateWindowListener(mWindow, doc);
 
-  hal::Vibrate(aPattern, mWindow);
+  hal::Vibrate(pattern, mWindow);
   return true;
 }
 

dom/tests/mochitest/general/test_vibrator.html

@@ -23,29 +23,36 @@ function expectSuccess(param) {
   is(result, true, 'vibrate(' + param + ') must succeed.');
 }
 
-function testFailures() {
+function tests() {
+  // Some edge cases that the bindings should handle for us.
   expectSuccess(null);
   expectSuccess(undefined);
-  expectFailure(-1);
+  // -1 will be converted to the highest unsigned long then clamped.
+  expectSuccess(-1);
   expectSuccess('a');
-  expectFailure([100, -1]);
+  // -1 will be converted to the highest unsigned long then clamped.
+  expectSuccess([100, -1]);
   expectSuccess([100, 'a']);
 
   var maxVibrateMs = SpecialPowers.getIntPref('dom.vibrator.max_vibrate_ms');
   var maxVibrateListLen = SpecialPowers.getIntPref('dom.vibrator.max_vibrate_list_len');
 
-  // Make sure that these preferences are respected.
-  expectFailure(maxVibrateMs + 1);
-  expectFailure([maxVibrateMs + 1]);
+  // If we pass a vibration pattern with a value higher than max_vibrate_ms or a
+  // pattern longer than max_vibrate_list_len, the call should succeed but the
+  // pattern should be modified to match the restrictions.
+
+  // Values will be clamped to dom.vibrator.max_vibrate_ms.
+  expectSuccess(maxVibrateMs + 1);
+  expectSuccess([maxVibrateMs + 1]);
 
   var arr = [];
   for (var i = 0; i < maxVibrateListLen + 1; i++) {
     arr[i] = 0;
   }
-  expectFailure(arr);
-}
+  // The array will be truncated to have a length equal to dom.vibrator.max_vibrate_list_len.
+  expectSuccess(arr);
+
 
-function testSuccesses() {
   expectSuccess(0);
   expectSuccess([]);
   expectSuccess('1000');
@@ -68,15 +75,13 @@ var origVibratorEnabled = SpecialPowers.getBoolPref('dom.vibrator.enabled');
 // Test with the vibrator pref enabled.
 try {
   SpecialPowers.setBoolPref('dom.vibrator.enabled', true);
-  testFailures();
-  testSuccesses();
+  tests();
 
   // Everything should be the same when the vibrator is disabled -- in
   // particular, a disabled vibrator shouldn't eat failures we'd otherwise
   // observe.
   SpecialPowers.setBoolPref('dom.vibrator.enabled', false);
-  testFailures();
-  testSuccesses();
+  tests();
 }
 finally {
   SpecialPowers.setBoolPref('dom.vibrator.enabled', origVibratorEnabled);