Possible AVFormatContext leak in `MediaInfoWorker::Execute`

[OvOhao]

Possible AVFormatContext leak in MediaInfoWorker::Execute

I found a possible per-operation resource leak in MediaInfoWorker::Execute. The worker allocates and
opens an AVFormatContext (which owns an open file/IO handle and demuxer state). If
avformat_find_stream_info fails, the worker only calls SetError and returns — it never closes the
already-opened context. MediaInfoWorker has no destructor and OnError just rejects the promise, so
on this path the opened AVFormatContext (and its file/socket handle) is leaked for every failed call.
Ownership is only transferred to a self-freeing wrapper on the success path (OnOK), never on error.

File: src/media-info-worker.cc

Function: MediaInfoWorker::Execute (and MediaInfoWorker::OnError)

void MediaInfoWorker::Execute() {
    avFormatContext = avformat_alloc_context();
    if (!avFormatContext) { SetError("..."); return; }

    int openStatus = avformat_open_input(&avFormatContext, fileName.c_str(), NULL, options);
    if (openStatus < 0) { SetError("filePath could not be opened"); return; }  // ffmpeg frees ctx here

    if (avformat_find_stream_info(avFormatContext, NULL) < 0) {
        Napi::AsyncWorker::SetError("could not get stream info");
        // <-- returns with avFormatContext still OPEN and never closed
    }
}

void MediaInfoWorker::OnError(const Napi::Error& error) {
    deferred.Reject(error.Value());   // avFormatContext is never closed on the error path
}

1. avformat_alloc_context() + a successful avformat_open_input leave avFormatContext pointing at
   an opened input (file/IO handle + demuxer). (On avformat_open_input failure FFmpeg frees the
   context itself, so that branch is fine.)
2. When avformat_find_stream_info returns < 0 — reachable with a truncated/corrupt but openable
   media file — Execute sets the error and returns without calling avformat_close_input.
3. MediaInfoWorker has no destructor and OnError only rejects the promise. The success path
   (OnOK) is the only place that hands the pointer to an AvFormatContext ObjectWrap whose
   ~AvFormatContext calls avformat_close_input. On the error path that handoff never happens, so
   the context and its underlying handle leak once per failed getFileInfo call.

JS trigger:

const { getFileInfo } = require('@alex8088/node-ffprobe');
// a file that opens but whose stream info cannot be parsed (corrupt/truncated) rejects,
// leaking one AVFormatContext + file handle each time:
for (let i = 0; i < 10000; i++) {
  getFileInfo('./corrupt-but-openable.bin').catch(() => {});
}

Suggested fix: close the context on the failure path, e.g. call
avformat_close_input(&avFormatContext) when avformat_find_stream_info fails (or add a
MediaInfoWorker destructor / OnError cleanup that closes avFormatContext if it is still owned by
the worker).

[tugrul]

Thank you for your detailed explanation.

Fix in this commit 36253b6

Published to the NPM.