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createEvent broken by mutating strings

See original GitHub issue

adding an event with createEvent

{
Duration: 4880,
Effect: "",
Layer: 0,
MarginL: 0,
MarginR: 0,
MarginV: 0,
Name: "",
ReadOrder: 0,
Start: 7870,
Style: 1,
Text: "Text."
}

for some reason creates an event that looks like:

{
Duration: 4880,
Effect: "Text.",
Layer: 0,
MarginL: 0,
MarginR: 0,
MarginV: 0,
Name: "Text.",
ReadOrder: 0,
Start: 7870,
Style: 1,
Text: "Text."
}

breaking the entire renderer, adding more subtitles with the createEvent function overwrites the text, effect and name values of the previous events

Issue Analytics

State:
Created 3 years ago
Comments:5 (2 by maintainers)

Top GitHub Comments

1reaction

TFSThiagoBR98commented, Aug 8, 2021

WebIDL uses this 2 generated functions:

void EMSCRIPTEN_KEEPALIVE emscripten_bind_ASS_Event_set_Text_1(ASS_Event* self, char* arg0) {
  self->Text = arg0;
}

and its JS counterpart:

ASS_Event.prototype['set_Text'] = ASS_Event.prototype.set_Text = /** @suppress {undefinedVars, duplicate} */function(arg0) {
  var self = this.ptr;
  ensureCache.prepare();
  if (arg0 && typeof arg0 === 'object') arg0 = arg0.ptr;
  else arg0 = ensureString(arg0);
  _emscripten_bind_ASS_Event_set_Text_1(self, arg0);
};

Also the ensureString function:

function ensureString(value) {
  if (typeof value === 'string') {
    var intArray = intArrayFromString(value);
    var offset = ensureCache.alloc(intArray, HEAP8);
    ensureCache.copy(intArray, HEAP8, offset);
    return offset;
  }
  return value;
}

This uses the intArrayFromString function but Emscripten also have the stringToUTF8, see here

0reactions

ThaUnknowncommented, Oct 15, 2021

WebIDL uses this 2 generated functions:

void EMSCRIPTEN_KEEPALIVE emscripten_bind_ASS_Event_set_Text_1(ASS_Event* self, char* arg0) {
  self->Text = arg0;
}

and its JS counterpart:

ASS_Event.prototype['set_Text'] = ASS_Event.prototype.set_Text = /** @suppress {undefinedVars, duplicate} */function(arg0) {
  var self = this.ptr;
  ensureCache.prepare();
  if (arg0 && typeof arg0 === 'object') arg0 = arg0.ptr;
  else arg0 = ensureString(arg0);
  _emscripten_bind_ASS_Event_set_Text_1(self, arg0);
};

Also the ensureString function:

function ensureString(value) {
  if (typeof value === 'string') {
    var intArray = intArrayFromString(value);
    var offset = ensureCache.alloc(intArray, HEAP8);
    ensureCache.copy(intArray, HEAP8, offset);
    return offset;
  }
  return value;
}

This uses the intArrayFromString function but Emscripten also have the stringToUTF8, see here

so any chance this will get fixed?