From 4b4d1cada9dfae692304eacad24f0df1c9198c30 Mon Sep 17 00:00:00 2001
From: Jonathan Baudanza <jon@jonb.org>
Date: Sun, 1 Nov 2020 08:52:18 -0800
Subject: [PATCH] Add demuxer.interrupt()

---
 src/demux.cc       | 38 ++++++++++++++++++++++++++++++++++++++
 src/demux.h        |  2 ++
 types/Demuxer.d.ts |  5 +++++
 3 files changed, 45 insertions(+)

diff --git a/src/demux.cc b/src/demux.cc
index ef8c593..62fa3a0 100644
--- a/src/demux.cc
+++ b/src/demux.cc
@@ -42,6 +42,12 @@ void demuxerExecute(napi_env env, void* data) {
     return;
   }
 
+  // Use the user-defined opaque field as a boolean flag to signal if blocking I/O should
+  // be stopped. ffmpeg will periodically poll this value through the interrupt_callback.
+  c->format->opaque = 0;
+  c->format->interrupt_callback.callback = interrupt_callback;
+  c->format->interrupt_callback.opaque = &c->format->opaque;
+
   if (c->adaptor) {
     AVIOContext* avio_ctx = avio_alloc_context(nullptr, 0, 0, c->adaptor, &read_packet, nullptr, nullptr);
     if (!avio_ctx) {
@@ -108,6 +114,12 @@ void demuxerComplete(napi_env env,  napi_status asyncStatus, void* data) {
   c->status = napi_set_named_property(env, result, "forceClose", prop);
   REJECT_STATUS;
 
+  c->status = napi_create_function(env, "interrupt", NAPI_AUTO_LENGTH, interrupt,
+    c, &prop);
+  REJECT_STATUS;
+  c->status = napi_set_named_property(env, result, "interrupt", prop);
+  REJECT_STATUS;
+
   napi_status status;
   status = napi_resolve_deferred(env, c->_deferred, result);
   FLOATING_STATUS;
@@ -582,3 +594,29 @@ napi_value forceCloseInput(napi_env env, napi_callback_info info) {
   CHECK_STATUS;
   return result;
 }
+
+napi_value interrupt(napi_env env, napi_callback_info info) {
+  napi_status status;
+  napi_value result, formatJS, formatRefExt;
+  fmtCtxRef* fmtRef;
+  size_t argc = 0;
+
+  status = napi_get_cb_info(env, info, &argc, nullptr, &formatJS, nullptr);
+  CHECK_STATUS;
+  status = napi_get_named_property(env, formatJS, "_formatContextRef", &formatRefExt);
+  CHECK_STATUS;
+  status = napi_get_value_external(env, formatRefExt, (void**) &fmtRef);
+  CHECK_STATUS;
+
+  fmtRef->fmtCtx->opaque = (void *)1;
+
+  status = napi_get_undefined(env, &result);
+  CHECK_STATUS;
+
+  return result;
+}
+
+int interrupt_callback(void *opaque) {
+  int* i = (int*) opaque;
+  return *i;
+}
diff --git a/src/demux.h b/src/demux.h
index 7da0b5d..7052a42 100644
--- a/src/demux.h
+++ b/src/demux.h
@@ -53,6 +53,8 @@ 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);
+napi_value interrupt(napi_env env, napi_callback_info info);
+int interrupt_callback(void *opaque);
 
 struct demuxerCarrier : carrier {
   const char* filename = nullptr;
diff --git a/types/Demuxer.d.ts b/types/Demuxer.d.ts
index 6bcb223..008b6fd 100644
--- a/types/Demuxer.d.ts
+++ b/types/Demuxer.d.ts
@@ -76,6 +76,11 @@ export interface Demuxer extends Omit<FormatContext,
 	 * Abandon the demuxing process and forcibly close the file or stream without waiting for it to finish
 	 */
 	forceClose(): undefined
+
+	/**
+	  * This causes any currently blocking IO to be interrupted and raise an "Immediate exit requested" error.
+	  */
+	interrupt(): undefined;
 }
 
 /**