Add demuxer force close, improve demuxer cleanup on GC

Author: scriptorian

README.md

@@ -472,6 +472,8 @@ let demuxer = demuxerStream.demuxer({
 });
 ```
 
+To abandon the demuxing process and forcibly close the input file or stream, call the synchronous `forceClose()` method of the demuxer.
+
 ### Decoding
 
 Decoding is the process of taking a stream of compressed data in the form of _packets_ and converting it into uncompressed _frames_. In general, to decode an interleaved (multiplexed) media file, you need a decoder for each of the video and the audio streams. For the purpose of keeping the examples simple in this section, only a single stream is decoded. However, it is possible to set up more than one decoder - say for related video and audio streams - and run them asynchronously and in parallel, i.e. to decode the video and audio required to present a frame.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "beamcoder",
-  "version": "0.6.4",
+  "version": "0.6.5",
   "description": "Node.js native bindings to FFmpeg.",
   "main": "index.js",
   "types": "index.d.ts",

src/demux.cc

@@ -102,6 +102,12 @@ void demuxerComplete(napi_env env,  napi_status asyncStatus, void* data) {
   c->status = napi_set_named_property(env, result, "seek", prop);
   REJECT_STATUS;
 
+  c->status = napi_create_function(env, "forceClose", NAPI_AUTO_LENGTH, forceCloseInput,
+    nullptr, &prop);
+  REJECT_STATUS;
+  c->status = napi_set_named_property(env, result, "forceClose", prop);
+  REJECT_STATUS;
+
   napi_status status;
   status = napi_resolve_deferred(env, c->_deferred, result);
   FLOATING_STATUS;
@@ -520,3 +526,32 @@ napi_value seekFrame(napi_env env, napi_callback_info info) {
 
   return promise;
 };
+
+napi_value forceCloseInput(napi_env env, napi_callback_info info) {
+  napi_status status;
+  napi_value result, formatJS, formatExt;
+  AVFormatContext* format;
+  int ret;
+
+  size_t argc = 0;
+  status = napi_get_cb_info(env, info, &argc, nullptr, &formatJS, nullptr);
+  CHECK_STATUS;
+  status = napi_get_named_property(env, formatJS, "_formatContext", &formatExt);
+  CHECK_STATUS;
+  status = napi_get_value_external(env, formatExt, (void**) &format);
+  CHECK_STATUS;
+
+  if (format->pb != nullptr) {
+    ret = avio_closep(&format->pb);
+    if (ret < 0) {
+      NAPI_THROW_ERROR(avErrorMsg("Failed to force close demuxer resource: ", ret));
+    }
+  } else {
+    printf("DEBUG: Demuxer IO resource '%s' already closed or not managed by AVIO.\n",
+      (format->url != nullptr) ? format->url : "unknown");
+  }
+
+  status = napi_get_undefined(env, &result);
+  CHECK_STATUS;
+  return result;
+}

src/demux.h

@@ -52,6 +52,8 @@ napi_value seekFrame(napi_env env, napi_callback_info info);
 void demuxerFinalizer(napi_env env, void* data, void* hint);
 void readBufferFinalizer(napi_env env, void* data, void* hint);
 
+napi_value forceCloseInput(napi_env env, napi_callback_info info);
+
 struct demuxerCarrier : carrier {
   const char* filename = nullptr;
   Adaptor *adaptor = nullptr;

src/format.cc

@@ -3850,7 +3850,9 @@ void formatContextFinalizer(napi_env env, void* data, void* hint) {
   if (fc->protocol_blacklist != nullptr) {
     av_freep(fc->protocol_blacklist);
   } */
-  if (!adaptor) // crashes otherwise...
+  if (fc->iformat != nullptr)
+    avformat_close_input(&fc);
+  else if (!adaptor) // crashes otherwise...
     avformat_free_context(fc);
 }