add file handling code from --preload-file etc. in a pre-js, so that it will be able to start network access as early as possible

2 files changed, 5 insertions, 6 deletions

diff --git a/emcc b/emcc
index 2aa223db..4222caa3 100755
--- a/emcc
+++ b/emcc
@@ -1654,7 +1654,7 @@ try:
   # Embed and preload files
   if len(preload_files) + len(embed_files) > 0:
     logging.debug('setting up files')
-    file_args = []
+    file_args = ['--pre-run']
     if len(preload_files) > 0:
       file_args.append('--preload')
       file_args += preload_files
@@ -1665,11 +1665,8 @@ try:
       file_args += ['--compress', Compression.encoder, Compression.decoder, Compression.js_name]
     if use_preload_cache:
       file_args.append('--use-preload-cache')
-    code = execute([shared.PYTHON, shared.FILE_PACKAGER, unsuffixed(target) + '.data'] + file_args, stdout=PIPE)[0]
-    src = open(final).read().replace('// {{PRE_RUN_ADDITIONS}}', '// {{PRE_RUN_ADDITIONS}}\n' + code)
-    final += '.files.js'
-    open(final, 'w').write(src)
-    if DEBUG: save_intermediate('files')
+    file_code = execute([shared.PYTHON, shared.FILE_PACKAGER, unsuffixed(target) + '.data'] + file_args, stdout=PIPE)[0]
+    pre_js = file_code + pre_js
 
   # Apply pre and postjs files
   if pre_js or post_js:
diff --git a/tools/file_packager.py b/tools/file_packager.py
index ea314be7..1180870b 100644
--- a/tools/file_packager.py
+++ b/tools/file_packager.py
@@ -15,6 +15,8 @@ Usage:
 
   --pre-run Will generate wrapper code that does preloading in Module.preRun. This is necessary if you add this
             code before the main file has been loading, which includes necessary components like addRunDependency.
+            (This is how emcc --preload-file etc. work, i.e., it is the normal mode of operation. However, for
+            data loaded later, say using emscripten_async_load_script, you do not need --pre-run.)
 
   --crunch=X Will compress dxt files to crn with quality level X. The crunch commandline tool must be present
              and CRUNCH should be defined in ~/.emscripten that points to it. JS crunch decompressing code will