1# vim: ft=python fileencoding=utf-8 sts=4 sw=4 et:
2
3# Copyright 2016-2021 Florian Bruhin (The Compiler) <mail@qutebrowser.org>
4#
5# This file is part of qutebrowser.
6#
7# qutebrowser is free software: you can redistribute it and/or modify
8# it under the terms of the GNU General Public License as published by
9# the Free Software Foundation, either version 3 of the License, or
10# (at your option) any later version.
11#
12# qutebrowser is distributed in the hope that it will be useful,
13# but WITHOUT ANY WARRANTY; without even the implied warranty of
14# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15# GNU General Public License for more details.
16#
17# You should have received a copy of the GNU General Public License
18# along with qutebrowser.  If not, see <https://www.gnu.org/licenses/>.
19
20"""Utilities related to javascript interaction."""
21
22from typing import Sequence, Union
23
24_InnerJsArgType = Union[None, str, bool, int, float]
25_JsArgType = Union[_InnerJsArgType, Sequence[_InnerJsArgType]]
26
27
28def string_escape(text: str) -> str:
29    """Escape values special to javascript in strings.
30
31    With this we should be able to use something like:
32      elem.evaluateJavaScript("this.value='{}'".format(string_escape(...)))
33    And all values should work.
34    """
35    # This is a list of tuples because order matters, and using OrderedDict
36    # makes no sense because we don't actually need dict-like properties.
37    replacements = (
38        ('\\', r'\\'),  # First escape all literal \ signs as \\.
39        ("'", r"\'"),   # Then escape ' and " as \' and \".
40        ('"', r'\"'),   # (note it won't hurt when we escape the wrong one).
41        ('\n', r'\n'),  # We also need to escape newlines for some reason.
42        ('\r', r'\r'),
43        ('\x00', r'\x00'),
44        ('\ufeff', r'\ufeff'),
45        # https://stackoverflow.com/questions/2965293/
46        ('\u2028', r'\u2028'),
47        ('\u2029', r'\u2029'),
48    )
49    for orig, repl in replacements:
50        text = text.replace(orig, repl)
51    return text
52
53
54def to_js(arg: _JsArgType) -> str:
55    """Convert the given argument so it's the equivalent in JS."""
56    if arg is None:
57        return 'undefined'
58    elif isinstance(arg, str):
59        return '"{}"'.format(string_escape(arg))
60    elif isinstance(arg, bool):
61        return str(arg).lower()
62    elif isinstance(arg, (int, float)):
63        return str(arg)
64    elif isinstance(arg, list):
65        return '[{}]'.format(', '.join(to_js(e) for e in arg))
66    else:
67        raise TypeError("Don't know how to handle {!r} of type {}!".format(
68            arg, type(arg).__name__))
69
70
71def assemble(module: str, function: str, *args: _JsArgType) -> str:
72    """Assemble a javascript file and a function call."""
73    js_args = ', '.join(to_js(arg) for arg in args)
74    if module == 'window':
75        parts = ['window', function]
76    else:
77        parts = ['window', '_qutebrowser', module, function]
78    code = '"use strict";\n{}({});'.format('.'.join(parts), js_args)
79    return code
80
81
82def wrap_global(name: str, *sources: str) -> str:
83    """Wrap a script using window._qutebrowser."""
84    from qutebrowser.utils import jinja  # circular import
85    template = jinja.js_environment.get_template('global_wrapper.js')
86    return template.render(code='\n'.join(sources), name=name)
87