1# Extended prompt utilities.
2# Copyright (C) 2011-2013 Free Software Foundation, Inc.
3
4# This program is free software; you can redistribute it and/or modify
5# it under the terms of the GNU General Public License as published by
6# the Free Software Foundation; either version 3 of the License, or
7# (at your option) any later version.
8#
9# This program is distributed in the hope that it will be useful,
10# but WITHOUT ANY WARRANTY; without even the implied warranty of
11# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12# GNU General Public License for more details.
13#
14# You should have received a copy of the GNU General Public License
15# along with this program.  If not, see <http://www.gnu.org/licenses/>.
16
17""" Extended prompt library functions."""
18
19import gdb
20import os
21
22def _prompt_pwd(ignore):
23    "The current working directory."
24    return os.getcwdu()
25
26def _prompt_object_attr(func, what, attr, nattr):
27    """Internal worker for fetching GDB attributes."""
28    if attr is None:
29        attr = nattr
30    try:
31        obj = func()
32    except gdb.error:
33        return '<no %s>' % what
34    if hasattr(obj, attr):
35        result = getattr(obj, attr)
36        if callable(result):
37            result = result()
38        return result
39    else:
40        return '<no attribute %s on current %s>' % (attr, what)
41
42def _prompt_frame(attr):
43    "The selected frame; an argument names a frame parameter."
44    return _prompt_object_attr(gdb.selected_frame, 'frame', attr, 'name')
45
46def _prompt_thread(attr):
47    "The selected thread; an argument names a thread parameter."
48    return _prompt_object_attr(gdb.selected_thread, 'thread', attr, 'num')
49
50def _prompt_version(attr):
51    "The version of GDB."
52    return gdb.VERSION
53
54def _prompt_esc(attr):
55    "The ESC character."
56    return '\033'
57
58def _prompt_bs(attr):
59    "A backslash."
60    return '\\'
61
62def _prompt_n(attr):
63    "A newline."
64    return '\n'
65
66def _prompt_r(attr):
67    "A carriage return."
68    return '\r'
69
70def _prompt_param(attr):
71    "A parameter's value; the argument names the parameter."
72    return gdb.parameter(attr)
73
74def _prompt_noprint_begin(attr):
75    "Begins a sequence of non-printing characters."
76    return '\001'
77
78def _prompt_noprint_end(attr):
79     "Ends a sequence of non-printing characters."
80     return '\002'
81
82prompt_substitutions = {
83    'e': _prompt_esc,
84    '\\': _prompt_bs,
85    'n': _prompt_n,
86    'r': _prompt_r,
87    'v': _prompt_version,
88    'w': _prompt_pwd,
89    'f': _prompt_frame,
90    't': _prompt_thread,
91    'p': _prompt_param,
92    '[': _prompt_noprint_begin,
93    ']': _prompt_noprint_end
94}
95
96def prompt_help():
97    """Generate help dynamically from the __doc__ strings of attribute
98    functions."""
99
100    result = ''
101    keys = sorted (prompt_substitutions.keys())
102    for key in keys:
103        result += '  \\%s\t%s\n' % (key, prompt_substitutions[key].__doc__)
104    result += """
105A substitution can be used in a simple form, like "\\f".
106An argument can also be passed to it, like "\\f{name}".
107The meaning of the argument depends on the particular substitution."""
108    return result
109
110def substitute_prompt(prompt):
111    "Perform substitutions on PROMPT."
112
113    result = ''
114    plen = len(prompt)
115    i = 0
116    while i < plen:
117        if prompt[i] == '\\':
118            i = i + 1
119            if i >= plen:
120                break
121            cmdch = prompt[i]
122
123            if cmdch in prompt_substitutions:
124                cmd = prompt_substitutions[cmdch]
125
126                if i + 1 < plen and prompt[i + 1] == '{':
127                    j = i + 1
128                    while j < plen and prompt[j] != '}':
129                        j = j + 1
130                    # Just ignore formatting errors.
131                    if j >= plen or prompt[j] != '}':
132                        arg = None
133                    else:
134                        arg = prompt[i + 2 : j]
135                        i = j
136                else:
137                    arg = None
138                result += str(cmd(arg))
139            else:
140                # Unrecognized escapes are turned into the escaped
141                # character itself.
142                result += prompt[i]
143        else:
144            result += prompt[i]
145
146        i = i + 1
147
148    return result
149