* Move pure JS functions to pre.js

* Add read timeout & fetch timeout (30s)
* Improve aborting behavior
* Add support for retrying after read() failures
* Trigger AbortSignal before aborting ffmpeg process - to help ensure
  fetches are aborted

Author: camgaertner

Makefile

@@ -26,7 +26,7 @@ EFLAGS=\
 	-s MODULARIZE=1 \
 	-s STACK_SIZE=1048576 \
 	-s ASYNCIFY \
-	-s "ASYNCIFY_IMPORTS=['libavjs_wait_reader', 'jsfetch_open_js']" \
+	-s "ASYNCIFY_IMPORTS=['libavjs_wait_reader', 'jsfetch_open_js', 'jsfetch_read', 'jsfetch_read_js']" \
 	-s INITIAL_MEMORY=25165824 \
 	-s ALLOW_MEMORY_GROWTH=1
 

Makefile.m4

@@ -26,7 +26,7 @@ EFLAGS=\
 	-s MODULARIZE=1 \
 	-s STACK_SIZE=1048576 \
 	-s ASYNCIFY \
-	-s "ASYNCIFY_IMPORTS=['libavjs_wait_reader', 'jsfetch_open_js']" \
+	-s "ASYNCIFY_IMPORTS=['libavjs_wait_reader', 'jsfetch_open_js', 'jsfetch_read', 'jsfetch_read_js']" \
 	-s INITIAL_MEMORY=25165824 \
 	-s ALLOW_MEMORY_GROWTH=1
 

dist/libav-6.5.7.1-h264-aac-mp3.wasm.mjs

@@ -973,8 +973,8 @@ static int64_t getmaxrss(void)
 
 void ffmpeg_interrupt(void);
 void ffmpeg_interrupt() {
-    received_nb_signals++;
     jsfetch_abort_request();
+    received_nb_signals++;
 }
 
 int ffmpeg_main(int argc, char **argv);