js/src/GeneratePrefs.py

   1 # This Source Code Form is subject to the terms of the Mozilla Public
   2 # License, v. 2.0. If a copy of the MPL was not distributed with this
   3 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
   4
   5 # This script generates js/public/PrefsGenerated.h from StaticPrefList.yaml
   6
   7 import buildconfig
   8 import six
   9 import yaml
  10 from mozbuild.preprocessor import Preprocessor
  11
  12 HEADER_TEMPLATE = """\
  13 /* This Source Code Form is subject to the terms of the Mozilla Public
  14  * License, v. 2.0. If a copy of the MPL was not distributed with this
  15  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
  16
  17 #ifndef js_PrefsGenerated_h
  18 #define js_PrefsGenerated_h
  19
  20 /* This file is generated by js/src/GeneratePrefs.py. Do not edit! */
  21
  22 #include "mozilla/Atomics.h"
  23
  24 #include <stdint.h>
  25
  26 %(contents)s
  27
  28 #endif // js_PrefsGenerated_h
  29 """
  30
  31
  32 def load_yaml(yaml_path):
  33     # First invoke the preprocessor to handle #ifdefs in the YAML file.
  34     pp = Preprocessor()
  35     pp.context.update(buildconfig.defines["ALLDEFINES"])
  36
  37     # To make #ifdef DEBUG work, use a similar hack as in emit_code in
  38     # generate_static_pref_list.py.
  39     if buildconfig.substs.get("MOZ_DEBUG"):
  40         pp.context["DEBUG"] = "1"
  41
  42     pp.out = six.StringIO()
  43     pp.do_filter("substitution")
  44     pp.do_include(yaml_path)
  45     contents = pp.out.getvalue()
  46     return yaml.safe_load(contents)
  47
  48
  49 # Returns the C++ type to use for the pref type from the YAML file. Always use
  50 # the non-atomic type for return values and arguments. The field type is
  51 # determined elsewhere.
  52 def get_cpp_type(type):
  53     if type in ("bool", "RelaxedAtomicBool"):
  54         return "bool"
  55     if type in ("uint32_t", "RelaxedAtomicUint32"):
  56         return "uint32_t"
  57     if type in ("int32_t", "RelaxedAtomicInt32"):
  58         return "int32_t"
  59     raise Exception("Unexpected type: {}".format(type))
  60
  61
  62 # Returns a C++ expression for the default pref value. Booleans in the YAML file
  63 # are converted to Pythonic True or False, so those need special handling.
  64 def get_cpp_init_value(val):
  65     if val is True:
  66         return "true"
  67     if val is False:
  68         return "false"
  69     return str(val)
  70
  71
  72 def generate_prefs_header(c_out, yaml_path):
  73     prefs = load_yaml(yaml_path)
  74
  75     js_options_prefix = "javascript.options."
  76
  77     def is_js_pref(pref):
  78         set_spidermonkey_pref = pref.get("set_spidermonkey_pref", False)
  79         if set_spidermonkey_pref not in (False, "startup", "always"):
  80             raise Exception("Invalid value for set_spidermonkey_pref")
  81
  82         # Ignore prefs that don't have the |set_spidermonkey_pref| attribute.
  83         if set_spidermonkey_pref is False:
  84             return False
  85
  86         # Only support prefs with javascript.options prefix.
  87         if not pref["name"].startswith(js_options_prefix):
  88             raise Exception("set_spidermonkey_pref only works for JS prefs")
  89
  90         return True
  91
  92     # Remove all non-JS prefs and sort prefs by name.
  93     prefs = list(filter(is_js_pref, prefs))
  94     prefs.sort(key=lambda pref: pref["name"])
  95
  96     class_fields = []
  97     class_fields_inits = []
  98
  99     macro_entries = []
 100     browser_set_statements = []
 101     browser_set_non_startup_statements = []
 102
 103     for pref in prefs:
 104         name = pref["name"]
 105         name = name[len(js_options_prefix) :]
 106
 107         is_startup_pref = pref["set_spidermonkey_pref"] == "startup"
 108
 109         cpp_name = name.replace(".", "_").replace("-", "_")
 110         type = get_cpp_type(pref["type"])
 111         init_value = get_cpp_init_value(pref["value"])
 112
 113         setter_name = ("setAtStartup_" if is_startup_pref else "set_") + cpp_name
 114
 115         # Use a relaxed atomic for non-startup prefs because those might be changed
 116         # after startup.
 117         field_type = type
 118         if not is_startup_pref:
 119             field_type = "mozilla::Atomic<{}, mozilla::Relaxed>".format(field_type)
 120         class_fields.append("static {} {}_;".format(field_type, cpp_name))
 121         class_fields_inits.append(
 122             "{} JS::Prefs::{}_{{{}}};".format(field_type, cpp_name, init_value)
 123         )
 124
 125         is_startup_pref_bool = "true" if is_startup_pref else "false"
 126
 127         # Generate a MACRO invocation like this:
 128         #   MACRO("arraybuffer_transfer", arraybuffer_transfer, bool, setAtStartup_arraybuffer_transfer, true)
 129         macro_entries.append(
 130             'MACRO("{}", {}, {}, {}, {})'.format(
 131                 name, cpp_name, type, setter_name, is_startup_pref_bool
 132             )
 133         )
 134
 135         # Generate a C++ statement to set the JS pref based on Gecko's StaticPrefs:
 136         #   JS::Prefs::setAtStartup_foo(StaticPrefs::javascript_options_foo());
 137         browser_pref_cpp_name = pref["name"].replace(".", "_").replace("-", "_")
 138         if pref.get("do_not_use_directly", False):
 139             browser_pref_cpp_name += "_DoNotUseDirectly"
 140
 141         statement = "JS::Prefs::{}(mozilla::StaticPrefs::{}());".format(
 142             setter_name, browser_pref_cpp_name
 143         )
 144         browser_set_statements.append(statement)
 145
 146         # For non-startup prefs, also generate code to update the pref after startup.
 147         if not is_startup_pref:
 148             browser_set_non_startup_statements.append(statement)
 149
 150     contents = ""
 151
 152     contents += "#define JS_PREF_CLASS_FIELDS \\\n"
 153     contents += "".join(map(lambda s: "  {}\\\n".format(s), class_fields))
 154     contents += "\n\n"
 155
 156     contents += "#define JS_PREF_CLASS_FIELDS_INIT \\\n"
 157     contents += "".join(map(lambda s: "  {}\\\n".format(s), class_fields_inits))
 158     contents += "\n\n"
 159
 160     contents += "#define FOR_EACH_JS_PREF(MACRO) \\\n"
 161     contents += "".join(map(lambda s: "  {}\\\n".format(s), macro_entries))
 162     contents += "\n\n"
 163
 164     contents += "#define SET_JS_PREFS_FROM_BROWSER_PREFS \\\n"
 165     contents += "".join(map(lambda s: "  {}\\\n".format(s), browser_set_statements))
 166     contents += "\n\n"
 167
 168     contents += "#define SET_NON_STARTUP_JS_PREFS_FROM_BROWSER_PREFS \\\n"
 169     contents += "".join(
 170         map(lambda s: "  {}\\\n".format(s), browser_set_non_startup_statements)
 171     )
 172     contents += "\n\n"
 173
 174     c_out.write(
 175         HEADER_TEMPLATE
 176         % {
 177             "contents": contents,
 178         }
 179     )