Function mozjs::jsapi::JS::NewReadableExternalSourceStreamObject

pub unsafe extern "C" fn NewReadableExternalSourceStreamObject(
    cx: *mut JSContext,
    underlyingSource: *mut ReadableStreamUnderlyingSource,
    nsISupportsObject_alreadyAddreffed: *mut c_void,
    proto: Handle<*mut JSObject>,
) -> *mut JSObject

Returns a new instance of the ReadableStream builtin class in the current compartment.

The instance is a byte stream backed by an embedding-provided underlying source, using the virtual methods of underlyingSource as callbacks. The embedding must ensure that *underlyingSource lives as long as the new stream object. The JS engine will call the finalize() method when the stream object is destroyed.

nsISupportsObject_alreadyAddreffed is an optional pointer that can be used to make the new stream participate in Gecko’s cycle collection. Here are the rules for using this parameter properly:

• *underlyingSource must not be a cycle-collected object. (It would lead to memory leaks as the cycle collector would not be able to collect cycles containing that object.)

• *underlyingSource must not contain nsCOMPtrs that point to cycle- collected objects. (Same reason.)

• *underlyingSource may contain a pointer to a single cycle-collected object.

• The pointer may be stored in *underlyingSource as a raw pointer.

• The pointer to the nsISupports interface of the same object must be passed as the nsISupportsObject_alreadyAddreffed parameter to this function. (This is how the cycle collector knows about it, so omitting this would again cause leaks.)

If proto is non-null, it is used as the instance’s [[Prototype]] instead of the original value of ReadableStream.prototype.