Function mozjs::jsapi::NewExternalArrayBuffer

pub unsafe extern "C" fn NewExternalArrayBuffer(
    cx: *mut JSContext,
    nbytes: usize,
    contents: *mut c_void,
    freeFunc: Option<unsafe extern "C" fn(_: *mut c_void, _: *mut c_void)>,
    freeUserData: *mut c_void,
) -> *mut JSObject

Create a new ArrayBuffer with the given contents. The contents must not be modified by any other code, internal or external.

!!! IMPORTANT !!! If and only if an ArrayBuffer is successfully created and returned, ownership of |contents| is transferred to the new ArrayBuffer.

When the ArrayBuffer is ready to be disposed of, freeFunc(contents, freeUserData) will be called to release the ArrayBuffer’s reference on the contents.

freeFunc() must not call any JSAPI functions that could cause a garbage collection.

The caller must keep the buffer alive until freeFunc() is called, or, if freeFunc is null, until the JSRuntime is destroyed.

The caller must not access the buffer on other threads. The JS engine will not allow the buffer to be transferred to other threads. If you try to transfer an external ArrayBuffer to another thread, the data is copied to a new malloc buffer. freeFunc() must be threadsafe, and may be called from any thread.

This allows ArrayBuffers to be used with embedder objects that use reference counting, for example. In that case the caller is responsible for incrementing the reference count before passing the contents to this function. This also allows using non-reference-counted contents that must be freed with some function other than free().