Fixed crash caused by NaN values in RCTTouchEvent

Summary:
React Native uses JSON to marshal the data across the bridge.
And because of this we have to avoid using NaN and INF values in events and other pieces of data that suppose to be transfered to/from JS side.
(We also don't want to introduce additional wrapping/escaping semantics for perfomance reasons.)
So, we have to gate all particular cases where there is a possibility of NaN or INF values, and replace these value with something meaningful for each particular case.
We are using `0` as NaN substitution here because:
 * NaN in touch event is super rare case;
 * Conversion to `0` is fast;
 * `0` is okay value for product code in most cases;
 * In all cases `0` is decent analog to "undefined position on screen" for touch event;
 * Nobody will explicitly handle NaN case in product code, just because it is super rare case and actually indicates that something else went wrong.

Reviewed By: javache

Differential Revision: D4918669

fbshipit-source-id: e95fa29e59dcdc40b57519e307b74c1f293da188
This commit is contained in:
Valentin Shergin 2017-04-21 11:25:31 -07:00 committed by Facebook Github Bot
parent 13f89f4e38
commit e7c6a4c038
3 changed files with 18 additions and 5 deletions

View File

@ -156,17 +156,17 @@ RCT_NOT_IMPLEMENTED(- (instancetype)initWithTarget:(id)target action:(SEL)action
CGPoint touchViewLocation = [nativeTouch.window convertPoint:windowLocation toView:touchView];
NSMutableDictionary *reactTouch = _reactTouches[touchIndex];
reactTouch[@"pageX"] = @(rootViewLocation.x);
reactTouch[@"pageY"] = @(rootViewLocation.y);
reactTouch[@"locationX"] = @(touchViewLocation.x);
reactTouch[@"locationY"] = @(touchViewLocation.y);
reactTouch[@"pageX"] = @(RCTSanitizeNaNValue(rootViewLocation.x, @"touchEvent.pageX"));
reactTouch[@"pageY"] = @(RCTSanitizeNaNValue(rootViewLocation.y, @"touchEvent.pageY"));
reactTouch[@"locationX"] = @(RCTSanitizeNaNValue(touchViewLocation.x, @"touchEvent.locationX"));
reactTouch[@"locationY"] = @(RCTSanitizeNaNValue(touchViewLocation.y, @"touchEvent.locationY"));
reactTouch[@"timestamp"] = @(nativeTouch.timestamp * 1000); // in ms, for JS
// TODO: force for a 'normal' touch is usually 1.0;
// should we expose a `normalTouchForce` constant somewhere (which would
// have a value of `1.0 / nativeTouch.maximumPossibleForce`)?
if (RCTForceTouchAvailable()) {
reactTouch[@"force"] = @(RCTZeroIfNaN(nativeTouch.force / nativeTouch.maximumPossibleForce));
reactTouch[@"force"] = @(RCTSanitizeNaNValue(nativeTouch.force / nativeTouch.maximumPossibleForce, @"touchEvent.force"));
}
}

View File

@ -101,6 +101,9 @@ RCT_EXTERN NSError *RCTErrorWithMessage(NSString *message);
// Convert NaN or infinite values to zero, as these aren't JSON-safe
RCT_EXTERN double RCTZeroIfNaN(double value);
// Returns `0` and log special warning if value is NaN or INF.
RCT_EXTERN double RCTSanitizeNaNValue(double value, NSString *property);
// Convert data to a Base64-encoded data URL
RCT_EXTERN NSURL *RCTDataURL(NSString *mimeType, NSData *data);

View File

@ -513,6 +513,16 @@ double RCTZeroIfNaN(double value)
return isnan(value) || isinf(value) ? 0 : value;
}
double RCTSanitizeNaNValue(double value, NSString *property)
{
if (!isnan(value) && !isinf(value)) {
return value;
}
RCTLogWarn(@"The value `%@` equals NaN or INF and will be replaced by `0`.", property);
return 0;
}
NSURL *RCTDataURL(NSString *mimeType, NSData *data)
{
return [NSURL URLWithString: