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7b51bc51 | 1 | # Pretty-printer utilities. |
ecd75fc8 | 2 | # Copyright (C) 2010-2014 Free Software Foundation, Inc. |
7b51bc51 DE |
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 | """Utilities for working with pretty-printers.""" | |
18 | ||
19 | import gdb | |
20 | import gdb.types | |
21 | import re | |
9a27f2c6 | 22 | import sys |
7b51bc51 | 23 | |
9a27f2c6 PK |
24 | if sys.version_info[0] > 2: |
25 | # Python 3 removed basestring and long | |
26 | basestring = str | |
27 | long = int | |
7b51bc51 DE |
28 | |
29 | class PrettyPrinter(object): | |
30 | """A basic pretty-printer. | |
31 | ||
32 | Attributes: | |
33 | name: A unique string among all printers for the context in which | |
690a4937 DE |
34 | it is defined (objfile, progspace, or global(gdb)), and should |
35 | meaningfully describe what can be pretty-printed. | |
36 | E.g., "StringPiece" or "protobufs". | |
7b51bc51 | 37 | subprinters: An iterable object with each element having a `name' |
690a4937 DE |
38 | attribute, and, potentially, "enabled" attribute. |
39 | Or this is None if there are no subprinters. | |
7b51bc51 DE |
40 | enabled: A boolean indicating if the printer is enabled. |
41 | ||
42 | Subprinters are for situations where "one" pretty-printer is actually a | |
43 | collection of several printers. E.g., The libstdc++ pretty-printer has | |
44 | a pretty-printer for each of several different types, based on regexps. | |
45 | """ | |
46 | ||
47 | # While one might want to push subprinters into the subclass, it's | |
48 | # present here to formalize such support to simplify | |
49 | # commands/pretty_printers.py. | |
50 | ||
51 | def __init__(self, name, subprinters=None): | |
52 | self.name = name | |
53 | self.subprinters = subprinters | |
54 | self.enabled = True | |
55 | ||
56 | def __call__(self, val): | |
57 | # The subclass must define this. | |
58 | raise NotImplementedError("PrettyPrinter __call__") | |
59 | ||
60 | ||
61 | class SubPrettyPrinter(object): | |
62 | """Baseclass for sub-pretty-printers. | |
63 | ||
64 | Sub-pretty-printers needn't use this, but it formalizes what's needed. | |
65 | ||
66 | Attributes: | |
67 | name: The name of the subprinter. | |
68 | enabled: A boolean indicating if the subprinter is enabled. | |
69 | """ | |
70 | ||
71 | def __init__(self, name): | |
72 | self.name = name | |
73 | self.enabled = True | |
74 | ||
75 | ||
1fa57852 | 76 | def register_pretty_printer(obj, printer, replace=False): |
7b51bc51 DE |
77 | """Register pretty-printer PRINTER with OBJ. |
78 | ||
79 | The printer is added to the front of the search list, thus one can override | |
690a4937 DE |
80 | an existing printer if one needs to. Use a different name when overriding |
81 | an existing printer, otherwise an exception will be raised; multiple | |
82 | printers with the same name are disallowed. | |
7b51bc51 DE |
83 | |
84 | Arguments: | |
85 | obj: Either an objfile, progspace, or None (in which case the printer | |
690a4937 | 86 | is registered globally). |
7b51bc51 | 87 | printer: Either a function of one argument (old way) or any object |
690a4937 | 88 | which has attributes: name, enabled, __call__. |
1fa57852 DE |
89 | replace: If True replace any existing copy of the printer. |
90 | Otherwise if the printer already exists raise an exception. | |
7b51bc51 DE |
91 | |
92 | Returns: | |
93 | Nothing. | |
94 | ||
95 | Raises: | |
96 | TypeError: A problem with the type of the printer. | |
4e04c971 | 97 | ValueError: The printer's name contains a semicolon ";". |
6d64e6d4 | 98 | RuntimeError: A printer with the same name is already registered. |
7b51bc51 DE |
99 | |
100 | If the caller wants the printer to be listable and disableable, it must | |
101 | follow the PrettyPrinter API. This applies to the old way (functions) too. | |
102 | If printer is an object, __call__ is a method of two arguments: | |
103 | self, and the value to be pretty-printed. See PrettyPrinter. | |
104 | """ | |
105 | ||
106 | # Watch for both __name__ and name. | |
107 | # Functions get the former for free, but we don't want to use an | |
108 | # attribute named __foo__ for pretty-printers-as-objects. | |
109 | # If printer has both, we use `name'. | |
110 | if not hasattr(printer, "__name__") and not hasattr(printer, "name"): | |
111 | raise TypeError("printer missing attribute: name") | |
112 | if hasattr(printer, "name") and not hasattr(printer, "enabled"): | |
113 | raise TypeError("printer missing attribute: enabled") | |
114 | if not hasattr(printer, "__call__"): | |
115 | raise TypeError("printer missing attribute: __call__") | |
116 | ||
117 | if obj is None: | |
118 | if gdb.parameter("verbose"): | |
119 | gdb.write("Registering global %s pretty-printer ...\n" % name) | |
120 | obj = gdb | |
121 | else: | |
122 | if gdb.parameter("verbose"): | |
123 | gdb.write("Registering %s pretty-printer for %s ...\n" % | |
124 | (printer.name, obj.filename)) | |
125 | ||
126 | if hasattr(printer, "name"): | |
127 | if not isinstance(printer.name, basestring): | |
128 | raise TypeError("printer name is not a string") | |
4e04c971 DE |
129 | # If printer provides a name, make sure it doesn't contain ";". |
130 | # Semicolon is used by the info/enable/disable pretty-printer commands | |
7b51bc51 | 131 | # to delimit subprinters. |
4e04c971 DE |
132 | if printer.name.find(";") >= 0: |
133 | raise ValueError("semicolon ';' in printer name") | |
7b51bc51 DE |
134 | # Also make sure the name is unique. |
135 | # Alas, we can't do the same for functions and __name__, they could | |
136 | # all have a canonical name like "lookup_function". | |
137 | # PERF: gdb records printers in a list, making this inefficient. | |
1fa57852 DE |
138 | i = 0 |
139 | for p in obj.pretty_printers: | |
140 | if hasattr(p, "name") and p.name == printer.name: | |
141 | if replace: | |
142 | del obj.pretty_printers[i] | |
143 | break | |
144 | else: | |
145 | raise RuntimeError("pretty-printer already registered: %s" % | |
146 | printer.name) | |
147 | i = i + 1 | |
7b51bc51 DE |
148 | |
149 | obj.pretty_printers.insert(0, printer) | |
150 | ||
151 | ||
152 | class RegexpCollectionPrettyPrinter(PrettyPrinter): | |
153 | """Class for implementing a collection of regular-expression based pretty-printers. | |
154 | ||
155 | Intended usage: | |
156 | ||
157 | pretty_printer = RegexpCollectionPrettyPrinter("my_library") | |
158 | pretty_printer.add_printer("myclass1", "^myclass1$", MyClass1Printer) | |
159 | ... | |
160 | pretty_printer.add_printer("myclassN", "^myclassN$", MyClassNPrinter) | |
161 | register_pretty_printer(obj, pretty_printer) | |
162 | """ | |
163 | ||
164 | class RegexpSubprinter(SubPrettyPrinter): | |
165 | def __init__(self, name, regexp, gen_printer): | |
166 | super(RegexpCollectionPrettyPrinter.RegexpSubprinter, self).__init__(name) | |
167 | self.regexp = regexp | |
168 | self.gen_printer = gen_printer | |
169 | self.compiled_re = re.compile(regexp) | |
170 | ||
171 | def __init__(self, name): | |
172 | super(RegexpCollectionPrettyPrinter, self).__init__(name, []) | |
173 | ||
174 | def add_printer(self, name, regexp, gen_printer): | |
175 | """Add a printer to the list. | |
176 | ||
177 | The printer is added to the end of the list. | |
178 | ||
179 | Arguments: | |
180 | name: The name of the subprinter. | |
181 | regexp: The regular expression, as a string. | |
182 | gen_printer: A function/method that given a value returns an | |
690a4937 | 183 | object to pretty-print it. |
7b51bc51 DE |
184 | |
185 | Returns: | |
186 | Nothing. | |
187 | """ | |
188 | ||
189 | # NOTE: A previous version made the name of each printer the regexp. | |
190 | # That makes it awkward to pass to the enable/disable commands (it's | |
191 | # cumbersome to make a regexp of a regexp). So now the name is a | |
192 | # separate parameter. | |
193 | ||
194 | self.subprinters.append(self.RegexpSubprinter(name, regexp, | |
195 | gen_printer)) | |
196 | ||
197 | def __call__(self, val): | |
198 | """Lookup the pretty-printer for the provided value.""" | |
199 | ||
200 | # Get the type name. | |
201 | typename = gdb.types.get_basic_type(val.type).tag | |
202 | if not typename: | |
203 | return None | |
204 | ||
205 | # Iterate over table of type regexps to determine | |
206 | # if a printer is registered for that type. | |
207 | # Return an instantiation of the printer if found. | |
208 | for printer in self.subprinters: | |
209 | if printer.enabled and printer.compiled_re.search(typename): | |
210 | return printer.gen_printer(val) | |
211 | ||
212 | # Cannot find a pretty printer. Return None. | |
213 | return None | |
cafec441 TT |
214 | |
215 | # A helper class for printing enum types. This class is instantiated | |
216 | # with a list of enumerators to print a particular Value. | |
217 | class _EnumInstance: | |
218 | def __init__(self, enumerators, val): | |
219 | self.enumerators = enumerators | |
220 | self.val = val | |
221 | ||
222 | def to_string(self): | |
223 | flag_list = [] | |
224 | v = long(self.val) | |
225 | any_found = False | |
226 | for (e_name, e_value) in self.enumerators: | |
227 | if v & e_value != 0: | |
228 | flag_list.append(e_name) | |
229 | v = v & ~e_value | |
230 | any_found = True | |
231 | if not any_found or v != 0: | |
232 | # Leftover value. | |
233 | flag_list.append('<unknown: 0x%x>' % v) | |
234 | return "0x%x [%s]" % (self.val, " | ".join(flag_list)) | |
235 | ||
236 | class FlagEnumerationPrinter(PrettyPrinter): | |
237 | """A pretty-printer which can be used to print a flag-style enumeration. | |
238 | A flag-style enumeration is one where the enumerators are or'd | |
239 | together to create values. The new printer will print these | |
240 | symbolically using '|' notation. The printer must be registered | |
241 | manually. This printer is most useful when an enum is flag-like, | |
242 | but has some overlap. GDB's built-in printing will not handle | |
243 | this case, but this printer will attempt to.""" | |
244 | ||
245 | def __init__(self, enum_type): | |
246 | super(FlagEnumerationPrinter, self).__init__(enum_type) | |
247 | self.initialized = False | |
248 | ||
249 | def __call__(self, val): | |
250 | if not self.initialized: | |
251 | self.initialized = True | |
252 | flags = gdb.lookup_type(self.name) | |
253 | self.enumerators = [] | |
254 | for field in flags.fields(): | |
14e75d8e | 255 | self.enumerators.append((field.name, field.enumval)) |
cafec441 TT |
256 | # Sorting the enumerators by value usually does the right |
257 | # thing. | |
14e75d8e | 258 | self.enumerators.sort(key = lambda x: x.enumval) |
cafec441 TT |
259 | |
260 | if self.enabled: | |
261 | return _EnumInstance(self.enumerators, val) | |
262 | else: | |
263 | return None |