emscripten/tools/minimal_runtime_shell.py

189 строки
8.8 KiB
Python

import re
import sys
import os
import logging
sys.path.insert(1, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
from tools import shared
from tools import line_endings
logger = logging.getLogger('minimal_runtime_shell')
def generate_minimal_runtime_load_statement(target_basename):
prefix_statements = [] # Extra code to appear before the loader
then_statements = [] # Statements to appear inside a Promise .then() block after loading has finished
modularize_imports = [] # Import parameters to call the main JS runtime function with
# 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 shared.Settings.MINIMAL_RUNTIME_STREAMING_WASM_COMPILATION:
if shared.Settings.MIN_SAFARI_VERSION != shared.Settings.TARGET_NOT_SUPPORTED or shared.Settings.ENVIRONMENT_MAY_BE_NODE or shared.Settings.MIN_FIREFOX_VERSION < 58 or shared.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 = "WebAssembly.compileStreaming ? WebAssembly.compileStreaming(fetch('%s')) : binary('%s')" % (target_basename + '.wasm', target_basename + '.wasm')
else:
# WebAssembly.compileStreaming() is unconditionally supported:
download_wasm = "WebAssembly.compileStreaming(fetch('%s'))" % (target_basename + '.wasm')
elif shared.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 shared.Settings.MIN_SAFARI_VERSION != shared.Settings.TARGET_NOT_SUPPORTED or shared.Settings.ENVIRONMENT_MAY_BE_NODE or shared.Settings.MIN_FIREFOX_VERSION < 58 or shared.Settings.MIN_CHROME_VERSION < 61:
download_wasm = "!WebAssembly.instantiateStreaming && binary('%s')" % (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 = "binary('%s')" % (target_basename + '.wasm')
files_to_load = ["script('%s')" % (target_basename + '.js')] # Main JS file always in first entry
# Download separate memory initializer file .mem
if shared.Settings.MEM_INIT_METHOD == 1 and not shared.Settings.MEM_INIT_IN_WASM:
if shared.Settings.MODULARIZE:
modularize_imports += ['mem: r[%d]' % len(files_to_load)]
else:
then_statements += ["Module.mem = r[%d];" % len(files_to_load)]
files_to_load += ["binary('%s')" % (target_basename + '.mem')]
# Download .wasm file
if shared.Settings.WASM == 1 or not download_wasm:
if shared.Settings.MODULARIZE:
modularize_imports += ['wasm: r[%d]' % len(files_to_load)]
else:
then_statements += ["Module.wasm = r[%d];" % len(files_to_load)]
if download_wasm:
files_to_load += [download_wasm]
if shared.Settings.MODULARIZE and shared.Settings.USE_PTHREADS:
modularize_imports += ["worker: '{{{ PTHREAD_WORKER_FILE }}}'"]
# Download Wasm2JS code if target browser does not support WebAssembly
if shared.Settings.WASM == 2:
if shared.Settings.MODULARIZE:
modularize_imports += ['wasm: supportsWasm ? r[%d] : 0' % len(files_to_load)]
else:
then_statements += ["if (supportsWasm) Module.wasm = r[%d];" % len(files_to_load)]
files_to_load += ["supportsWasm ? %s : script('%s')" % (download_wasm, target_basename + '.wasm.js')]
# Execute compiled output when building with MODULARIZE
if shared.Settings.MODULARIZE:
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];\n js({ %s });''' % ',\n '.join(modularize_imports)]
binary_xhr = ''' function binary(url) { // Downloads a binary file and outputs it in the specified callback
return new Promise((ok, err) => {
var x = new XMLHttpRequest();
x.open('GET', url, true);
x.responseType = 'arraybuffer';
x.onload = () => { ok(x.response); }
x.send(null);
});
}
'''
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 shared.Settings.MODULARIZE:
return script_xhr + files_to_load[0] + ".then((js) => {\n js();\n});"
else:
return script_xhr + files_to_load[0] + ";"
if not shared.Settings.MODULARIZE:
# 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 shared.Settings.USE_PTHREADS:
script_load = "script(url)"
else:
script_load = "script(url).then(() => { URL.revokeObjectURL(url) });"
files_to_load[0] = "binary('%s')" % (target_basename + '.js')
then_statements += ["var url = URL.createObjectURL(new Blob([r[0]], { type: 'application/javascript' }));",
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 = open(options.shell_path, 'r').read()
if shared.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.configuration.get_temp_files()
with temp_files.get_file(suffix='.js') as shell_temp:
open(shell_temp, 'w').write(shell)
shell = shared.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 }}}', shared.Settings.EXPORT_NAME)
shell = shell.replace('{{{ PTHREAD_WORKER_FILE }}}', shared.Settings.PTHREAD_WORKER_FILE)
# In SINGLE_FILE build, embed the main .js file into the .html output
if shared.Settings.SINGLE_FILE:
js_contents = open(js_target).read()
shared.try_delete(js_target)
else:
js_contents = ''
shell = shell.replace('{{{ JS_CONTENTS_IN_SINGLE_FILE_BUILD }}}', js_contents)
shell = line_endings.convert_line_endings(shell, '\n', options.output_eol)
# Force UTF-8 output for consistency across platforms and with the web.
with open(target, 'wb') as f:
f.write(shell.encode('utf-8'))