tools/minimal_runtime_shell.py - external/github.com/emscripten-core/emscripten - Git at Google

 import re
 import sys
 import os
 import logging

 __scriptdir__ = os.path.dirname(os.path.abspath(__file__))
 __rootdir__ = os.path.dirname(__scriptdir__)
 sys.path.insert(0, __rootdir__)

 from . import building
 from . import shared
 from . import utils
 from . import feature_matrix
 from .settings import settings

 logger = logging.getLogger('minimal_runtime_shell')


 def generate_minimal_runtime_load_statement(target_basename):
   # Extra code to appear before the loader
   prefix_statements = []
   # Statements to appear inside a Promise .then() block after loading has finished
   then_statements = []
   # Import parameters to call the main JS runtime function with
   modularize_imports = []

   # Depending on whether streaming Wasm compilation is enabled or not, the minimal sized code to
   # download Wasm looks a bit different.
   # Expand {{{ DOWNLOAD_WASM }}} block from here (if we added #define support, this could be done in
   # the template directly)
   if settings.MINIMAL_RUNTIME_STREAMING_WASM_COMPILATION:
     if settings.MIN_SAFARI_VERSION != feature_matrix.UNSUPPORTED or settings.ENVIRONMENT_MAY_BE_NODE or settings.MIN_FIREFOX_VERSION < 58 or settings.MIN_CHROME_VERSION < 61:
       # Firefox 52 added Wasm support, but only Firefox 58 added compileStreaming.
       # Chrome 57 added Wasm support, but only Chrome 61 added compileStreaming.
       # https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WebAssembly/compileStreaming
       # In Safari and Node.js, WebAssembly.compileStreaming() is not supported, in which case fall back to regular download.
       download_wasm = f"WebAssembly.compileStreaming ? WebAssembly.compileStreaming(fetch('{target_basename}.wasm')) : binary('{target_basename}.wasm')"
     else:
       # WebAssembly.compileStreaming() is unconditionally supported:
       download_wasm = f"WebAssembly.compileStreaming(fetch('{target_basename}.wasm'))"
   elif settings.MINIMAL_RUNTIME_STREAMING_WASM_INSTANTIATION:
     # Same compatibility story as above for
     # https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WebAssembly/instantiateStreaming
     if settings.MIN_SAFARI_VERSION != feature_matrix.UNSUPPORTED or settings.ENVIRONMENT_MAY_BE_NODE or settings.MIN_FIREFOX_VERSION < 58 or settings.MIN_CHROME_VERSION < 61:
       download_wasm = f"!WebAssembly.instantiateStreaming && binary('{target_basename}.wasm')"
     else:
       # WebAssembly.instantiateStreaming() is unconditionally supported, so we do not download wasm
       # in the .html file, but leave it to the .js file to download
       download_wasm = None
   else:
     download_wasm = f"binary('{target_basename}.wasm')"

   # Main JS file always in first entry
   files_to_load = [f"script('{target_basename}.js')"]

   # Download .wasm file
   if (settings.WASM == 1 and settings.WASM2JS == 0) or not download_wasm:
     if settings.MODULARIZE:
       modularize_imports += [f'wasm: r[{len(files_to_load)}]']
     else:
       then_statements += [f"{settings.EXPORT_NAME}.wasm = r[{len(files_to_load)}];"]
     if download_wasm:
       files_to_load += [download_wasm]

   # Download wasm_worker file
   if settings.WASM_WORKERS:
     if settings.MODULARIZE:
       if settings.WASM_WORKERS == 1: # '$wb': Wasm Worker Blob
         modularize_imports += ["$wb: URL.createObjectURL(new Blob([r[%d]], { type: 'application/javascript' }))" % len(files_to_load)]
       modularize_imports += ['js: js']
     else:
       if settings.WASM_WORKERS == 1:
         then_statements += ["%s.$wb = URL.createObjectURL(new Blob([r[%d]], { type: 'application/javascript' }));" % (settings.EXPORT_NAME, len(files_to_load))]

     if download_wasm and settings.WASM_WORKERS == 1:
       files_to_load += [f"binary('{target_basename}.ww.js')"]

   # Download Wasm2JS code if target browser does not support WebAssembly
   if settings.WASM == 2:
     if settings.MODULARIZE:
       modularize_imports += [f'wasm: supportsWasm ? r[{len(files_to_load)}] : 0']
     else:
       then_statements += [f"if (supportsWasm) {settings.EXPORT_NAME}.wasm = r[{len(files_to_load)}];"]
     files_to_load += [f"supportsWasm ? {download_wasm} : script('{target_basename}.wasm.js')"]

   # Execute compiled output when building with MODULARIZE
   if settings.MODULARIZE:
     modularize_imports = ',\n  '.join(modularize_imports)
     if settings.WASM_WORKERS:
       then_statements += ['''\
   // Detour the JS code to a separate variable to avoid instantiating with 'r' array as "this"
   // directly to avoid strict ECMAScript/Firefox GC problems that cause a leak, see
   // https://bugzilla.mozilla.org/show_bug.cgi?id=1540101
   var js = URL.createObjectURL(new Blob([r[0]], { type: \'application/javascript\' }));
   script(js).then((c) => c({
   %s
   }));''' % modularize_imports]
     else:
       then_statements += ['''\
   // Detour the JS code to a separate variable to avoid instantiating with 'r' array as "this"
   // directly to avoid strict ECMAScript/Firefox GC problems that cause a leak, see
   // https://bugzilla.mozilla.org/show_bug.cgi?id=1540101
   var js = r[0];
   js({
   %s
   });''' % modularize_imports]

   binary_xhr = '  var binary = (url) => fetch(url).then((rsp) => rsp.arrayBuffer());'

   script_xhr = '''\
   function script(url) { // Downloads a script file and adds it to DOM
     return new Promise((ok, err) => {
       var s = document.createElement('script');
       s.src = url;
       s.onload = () => {
 #if MODULARIZE
 #if WASM == 2
         // In MODULARIZEd WASM==2 builds, we use this same function to download
         // both .js and .asm.js that are structured with {{{ EXPORT_NAME }}}
         // at the top level, but also use this function to download the Wasm2JS
         // file that does not have an {{{ EXPORT_NAME }}} function, hence the
         // variable typeof check:
         if (typeof {{{ EXPORT_NAME }}} !== 'undefined') {
           var c = {{{ EXPORT_NAME }}};
           delete {{{ EXPORT_NAME }}};
           ok(c);
         } else {
           ok();
         }
 #else
         var c = {{{ EXPORT_NAME }}};
         delete {{{ EXPORT_NAME }}};
         ok(c);
 #endif
 #else
         ok();
 #endif
       };
       document.body.appendChild(s);
     });
   }
   '''

   # Only one file to download - no need to use Promise.all()
   if len(files_to_load) == 1:
     if settings.MODULARIZE:
       return script_xhr + files_to_load[0] + ".then(js);"
     else:
       return script_xhr + files_to_load[0] + ";"

   if not settings.MODULARIZE or settings.WASM_WORKERS:
     # If downloading multiple files like .wasm or .mem, those need to be loaded in
     # before we can add the main runtime script to the DOM, so convert the main .js
     # script load from direct script() load to a binary() load so we can still
     # immediately start the download, but can control when we add the script to the
     # DOM.
     if settings.PTHREADS or settings.WASM_WORKERS:
       script_load = "script(url)"
     else:
       script_load = "script(url).then(() => URL.revokeObjectURL(url));"

     if settings.WASM_WORKERS:
       save_js = f'{settings.EXPORT_NAME}.js = '
     else:
       save_js = ''

     files_to_load[0] = f"binary('{target_basename}.js')"
     if not settings.MODULARIZE:
       then_statements += ["var url = %sURL.createObjectURL(new Blob([r[0]], { type: 'application/javascript' }));" % save_js,
                           script_load]

   # Add in binary() XHR loader if used:
   if any("binary(" in s for s in files_to_load + then_statements):
     prefix_statements += [binary_xhr]
   if any("script(" in s for s in files_to_load + then_statements):
     prefix_statements += [script_xhr]

   # Several files to download, go via Promise.all()
   load = '\n'.join(prefix_statements)
   load += "Promise.all([" + ', '.join(files_to_load) + "])"
   if len(then_statements) > 0:
     load += '.then((r) => {\n  %s\n});' % '\n  '.join(then_statements)
   return load


 def generate_minimal_runtime_html(target, options, js_target, target_basename):
   logger.debug('generating HTML for minimal runtime')
   shell = utils.read_file(options.shell_path)
   if settings.SINGLE_FILE:
     # No extra files needed to download in a SINGLE_FILE build.
     shell = shell.replace('{{{ DOWNLOAD_JS_AND_WASM_FILES }}}', '')
   else:
     shell = shell.replace('{{{ DOWNLOAD_JS_AND_WASM_FILES }}}', generate_minimal_runtime_load_statement(target_basename))

   temp_files = shared.get_temp_files()
   with temp_files.get_file(suffix='.js') as shell_temp:
     utils.write_file(shell_temp, shell)
     shell = building.read_and_preprocess(shell_temp)

   if re.search(r'{{{\s*SCRIPT\s*}}}', shell):
     shared.exit_with_error('--shell-file "' + options.shell_path + '": MINIMAL_RUNTIME uses a different kind of HTML page shell file than the traditional runtime! Please see $EMSCRIPTEN/src/shell_minimal_runtime.html for a template to use as a basis.')

   shell = shell.replace('{{{ TARGET_BASENAME }}}', target_basename)
   shell = shell.replace('{{{ EXPORT_NAME }}}', settings.EXPORT_NAME)
   shell = shell.replace('{{{ TARGET_JS_NAME }}}', settings.TARGET_JS_NAME)

   # In SINGLE_FILE build, embed the main .js file into the .html output
   if settings.SINGLE_FILE:
     js_contents = utils.read_file(js_target)
     utils.delete_file(js_target)
   else:
     js_contents = ''
   shell = shell.replace('{{{ JS_CONTENTS_IN_SINGLE_FILE_BUILD }}}', js_contents)
   utils.write_file(target, shell, options.output_eol)
	import re
	import sys
	import os
	import logging

	__scriptdir__ = os.path.dirname(os.path.abspath(__file__))
	__rootdir__ = os.path.dirname(__scriptdir__)
	sys.path.insert(0, __rootdir__)

	from . import building
	from . import shared
	from . import utils
	from . import feature_matrix
	from .settings import settings

	logger = logging.getLogger('minimal_runtime_shell')


	def generate_minimal_runtime_load_statement(target_basename):
	# Extra code to appear before the loader
	prefix_statements = []
	# Statements to appear inside a Promise .then() block after loading has finished
	then_statements = []
	# Import parameters to call the main JS runtime function with
	modularize_imports = []

	# Depending on whether streaming Wasm compilation is enabled or not, the minimal sized code to
	# download Wasm looks a bit different.
	# Expand {{{ DOWNLOAD_WASM }}} block from here (if we added #define support, this could be done in
	# the template directly)
	if settings.MINIMAL_RUNTIME_STREAMING_WASM_COMPILATION:
	if settings.MIN_SAFARI_VERSION != feature_matrix.UNSUPPORTED or settings.ENVIRONMENT_MAY_BE_NODE or settings.MIN_FIREFOX_VERSION < 58 or settings.MIN_CHROME_VERSION < 61:
	# Firefox 52 added Wasm support, but only Firefox 58 added compileStreaming.
	# Chrome 57 added Wasm support, but only Chrome 61 added compileStreaming.
	# https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WebAssembly/compileStreaming
	# In Safari and Node.js, WebAssembly.compileStreaming() is not supported, in which case fall back to regular download.
	download_wasm = f"WebAssembly.compileStreaming ? WebAssembly.compileStreaming(fetch('{target_basename}.wasm')) : binary('{target_basename}.wasm')"
	else:
	# WebAssembly.compileStreaming() is unconditionally supported:
	download_wasm = f"WebAssembly.compileStreaming(fetch('{target_basename}.wasm'))"
	elif settings.MINIMAL_RUNTIME_STREAMING_WASM_INSTANTIATION:
	# Same compatibility story as above for
	# https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WebAssembly/instantiateStreaming
	if settings.MIN_SAFARI_VERSION != feature_matrix.UNSUPPORTED or settings.ENVIRONMENT_MAY_BE_NODE or settings.MIN_FIREFOX_VERSION < 58 or settings.MIN_CHROME_VERSION < 61:
	download_wasm = f"!WebAssembly.instantiateStreaming && binary('{target_basename}.wasm')"
	else:
	# WebAssembly.instantiateStreaming() is unconditionally supported, so we do not download wasm
	# in the .html file, but leave it to the .js file to download
	download_wasm = None
	else:
	download_wasm = f"binary('{target_basename}.wasm')"

	# Main JS file always in first entry
	files_to_load = [f"script('{target_basename}.js')"]

	# Download .wasm file
	if (settings.WASM == 1 and settings.WASM2JS == 0) or not download_wasm:
	if settings.MODULARIZE:
	modularize_imports += [f'wasm: r[{len(files_to_load)}]']
	else:
	then_statements += [f"{settings.EXPORT_NAME}.wasm = r[{len(files_to_load)}];"]
	if download_wasm:
	files_to_load += [download_wasm]

	# Download wasm_worker file
	if settings.WASM_WORKERS:
	if settings.MODULARIZE:
	if settings.WASM_WORKERS == 1: # '$wb': Wasm Worker Blob
	modularize_imports += ["$wb: URL.createObjectURL(new Blob([r[%d]], { type: 'application/javascript' }))" % len(files_to_load)]
	modularize_imports += ['js: js']
	else:
	if settings.WASM_WORKERS == 1:
	then_statements += ["%s.$wb = URL.createObjectURL(new Blob([r[%d]], { type: 'application/javascript' }));" % (settings.EXPORT_NAME, len(files_to_load))]

	if download_wasm and settings.WASM_WORKERS == 1:
	files_to_load += [f"binary('{target_basename}.ww.js')"]

	# Download Wasm2JS code if target browser does not support WebAssembly
	if settings.WASM == 2:
	if settings.MODULARIZE:
	modularize_imports += [f'wasm: supportsWasm ? r[{len(files_to_load)}] : 0']
	else:
	then_statements += [f"if (supportsWasm) {settings.EXPORT_NAME}.wasm = r[{len(files_to_load)}];"]
	files_to_load += [f"supportsWasm ? {download_wasm} : script('{target_basename}.wasm.js')"]

	# Execute compiled output when building with MODULARIZE
	if settings.MODULARIZE:
	modularize_imports = ',\n '.join(modularize_imports)
	if settings.WASM_WORKERS:
	then_statements += ['''\
	// Detour the JS code to a separate variable to avoid instantiating with 'r' array as "this"
	// directly to avoid strict ECMAScript/Firefox GC problems that cause a leak, see
	// https://bugzilla.mozilla.org/show_bug.cgi?id=1540101
	var js = URL.createObjectURL(new Blob([r[0]], { type: \'application/javascript\' }));
	script(js).then((c) => c({
	%s
	}));''' % modularize_imports]
	else:
	then_statements += ['''\
	// Detour the JS code to a separate variable to avoid instantiating with 'r' array as "this"
	// directly to avoid strict ECMAScript/Firefox GC problems that cause a leak, see
	// https://bugzilla.mozilla.org/show_bug.cgi?id=1540101
	var js = r[0];
	js({
	%s
	});''' % modularize_imports]

	binary_xhr = ' var binary = (url) => fetch(url).then((rsp) => rsp.arrayBuffer());'

	script_xhr = '''\
	function script(url) { // Downloads a script file and adds it to DOM
	return new Promise((ok, err) => {
	var s = document.createElement('script');
	s.src = url;
	s.onload = () => {
	#if MODULARIZE
	#if WASM == 2
	// In MODULARIZEd WASM==2 builds, we use this same function to download
	// both .js and .asm.js that are structured with {{{ EXPORT_NAME }}}
	// at the top level, but also use this function to download the Wasm2JS
	// file that does not have an {{{ EXPORT_NAME }}} function, hence the
	// variable typeof check:
	if (typeof {{{ EXPORT_NAME }}} !== 'undefined') {
	var c = {{{ EXPORT_NAME }}};
	delete {{{ EXPORT_NAME }}};
	ok(c);
	} else {
	ok();
	}
	#else
	var c = {{{ EXPORT_NAME }}};
	delete {{{ EXPORT_NAME }}};
	ok(c);
	#endif
	#else
	ok();
	#endif
	};
	document.body.appendChild(s);
	});
	}
	'''

	# Only one file to download - no need to use Promise.all()
	if len(files_to_load) == 1:
	if settings.MODULARIZE:
	return script_xhr + files_to_load[0] + ".then(js);"
	else:
	return script_xhr + files_to_load[0] + ";"

	if not settings.MODULARIZE or settings.WASM_WORKERS:
	# If downloading multiple files like .wasm or .mem, those need to be loaded in
	# before we can add the main runtime script to the DOM, so convert the main .js
	# script load from direct script() load to a binary() load so we can still
	# immediately start the download, but can control when we add the script to the
	# DOM.
	if settings.PTHREADS or settings.WASM_WORKERS:
	script_load = "script(url)"
	else:
	script_load = "script(url).then(() => URL.revokeObjectURL(url));"

	if settings.WASM_WORKERS:
	save_js = f'{settings.EXPORT_NAME}.js = '
	else:
	save_js = ''

	files_to_load[0] = f"binary('{target_basename}.js')"
	if not settings.MODULARIZE:
	then_statements += ["var url = %sURL.createObjectURL(new Blob([r[0]], { type: 'application/javascript' }));" % save_js,
	script_load]

	# Add in binary() XHR loader if used:
	if any("binary(" in s for s in files_to_load + then_statements):
	prefix_statements += [binary_xhr]
	if any("script(" in s for s in files_to_load + then_statements):
	prefix_statements += [script_xhr]

	# Several files to download, go via Promise.all()
	load = '\n'.join(prefix_statements)
	load += "Promise.all([" + ', '.join(files_to_load) + "])"
	if len(then_statements) > 0:
	load += '.then((r) => {\n %s\n});' % '\n '.join(then_statements)
	return load


	def generate_minimal_runtime_html(target, options, js_target, target_basename):
	logger.debug('generating HTML for minimal runtime')
	shell = utils.read_file(options.shell_path)
	if settings.SINGLE_FILE:
	# No extra files needed to download in a SINGLE_FILE build.
	shell = shell.replace('{{{ DOWNLOAD_JS_AND_WASM_FILES }}}', '')
	else:
	shell = shell.replace('{{{ DOWNLOAD_JS_AND_WASM_FILES }}}', generate_minimal_runtime_load_statement(target_basename))

	temp_files = shared.get_temp_files()
	with temp_files.get_file(suffix='.js') as shell_temp:
	utils.write_file(shell_temp, shell)
	shell = building.read_and_preprocess(shell_temp)

	if re.search(r'{{{\sSCRIPT\s}}}', shell):
	shared.exit_with_error('--shell-file "' + options.shell_path + '": MINIMAL_RUNTIME uses a different kind of HTML page shell file than the traditional runtime! Please see $EMSCRIPTEN/src/shell_minimal_runtime.html for a template to use as a basis.')

	shell = shell.replace('{{{ TARGET_BASENAME }}}', target_basename)
	shell = shell.replace('{{{ EXPORT_NAME }}}', settings.EXPORT_NAME)
	shell = shell.replace('{{{ TARGET_JS_NAME }}}', settings.TARGET_JS_NAME)

	# In SINGLE_FILE build, embed the main .js file into the .html output
	if settings.SINGLE_FILE:
	js_contents = utils.read_file(js_target)
	utils.delete_file(js_target)
	else:
	js_contents = ''
	shell = shell.replace('{{{ JS_CONTENTS_IN_SINGLE_FILE_BUILD }}}', js_contents)
	utils.write_file(target, shell, options.output_eol)