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7b51bc51 | 1 | # Pretty-printer utilities. |
0b302171 | 2 | # Copyright (C) 2010-2012 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 | |
22 | ||
23 | ||
24 | class PrettyPrinter(object): | |
25 | """A basic pretty-printer. | |
26 | ||
27 | Attributes: | |
28 | name: A unique string among all printers for the context in which | |
690a4937 DE |
29 | it is defined (objfile, progspace, or global(gdb)), and should |
30 | meaningfully describe what can be pretty-printed. | |
31 | E.g., "StringPiece" or "protobufs". | |
7b51bc51 | 32 | subprinters: An iterable object with each element having a `name' |
690a4937 DE |
33 | attribute, and, potentially, "enabled" attribute. |
34 | Or this is None if there are no subprinters. | |
7b51bc51 DE |
35 | enabled: A boolean indicating if the printer is enabled. |
36 | ||
37 | Subprinters are for situations where "one" pretty-printer is actually a | |
38 | collection of several printers. E.g., The libstdc++ pretty-printer has | |
39 | a pretty-printer for each of several different types, based on regexps. | |
40 | """ | |
41 | ||
42 | # While one might want to push subprinters into the subclass, it's | |
43 | # present here to formalize such support to simplify | |
44 | # commands/pretty_printers.py. | |
45 | ||
46 | def __init__(self, name, subprinters=None): | |
47 | self.name = name | |
48 | self.subprinters = subprinters | |
49 | self.enabled = True | |
50 | ||
51 | def __call__(self, val): | |
52 | # The subclass must define this. | |
53 | raise NotImplementedError("PrettyPrinter __call__") | |
54 | ||
55 | ||
56 | class SubPrettyPrinter(object): | |
57 | """Baseclass for sub-pretty-printers. | |
58 | ||
59 | Sub-pretty-printers needn't use this, but it formalizes what's needed. | |
60 | ||
61 | Attributes: | |
62 | name: The name of the subprinter. | |
63 | enabled: A boolean indicating if the subprinter is enabled. | |
64 | """ | |
65 | ||
66 | def __init__(self, name): | |
67 | self.name = name | |
68 | self.enabled = True | |
69 | ||
70 | ||
1fa57852 | 71 | def register_pretty_printer(obj, printer, replace=False): |
7b51bc51 DE |
72 | """Register pretty-printer PRINTER with OBJ. |
73 | ||
74 | The printer is added to the front of the search list, thus one can override | |
690a4937 DE |
75 | an existing printer if one needs to. Use a different name when overriding |
76 | an existing printer, otherwise an exception will be raised; multiple | |
77 | printers with the same name are disallowed. | |
7b51bc51 DE |
78 | |
79 | Arguments: | |
80 | obj: Either an objfile, progspace, or None (in which case the printer | |
690a4937 | 81 | is registered globally). |
7b51bc51 | 82 | printer: Either a function of one argument (old way) or any object |
690a4937 | 83 | which has attributes: name, enabled, __call__. |
1fa57852 DE |
84 | replace: If True replace any existing copy of the printer. |
85 | Otherwise if the printer already exists raise an exception. | |
7b51bc51 DE |
86 | |
87 | Returns: | |
88 | Nothing. | |
89 | ||
90 | Raises: | |
91 | TypeError: A problem with the type of the printer. | |
4e04c971 | 92 | ValueError: The printer's name contains a semicolon ";". |
6d64e6d4 | 93 | RuntimeError: A printer with the same name is already registered. |
7b51bc51 DE |
94 | |
95 | If the caller wants the printer to be listable and disableable, it must | |
96 | follow the PrettyPrinter API. This applies to the old way (functions) too. | |
97 | If printer is an object, __call__ is a method of two arguments: | |
98 | self, and the value to be pretty-printed. See PrettyPrinter. | |
99 | """ | |
100 | ||
101 | # Watch for both __name__ and name. | |
102 | # Functions get the former for free, but we don't want to use an | |
103 | # attribute named __foo__ for pretty-printers-as-objects. | |
104 | # If printer has both, we use `name'. | |
105 | if not hasattr(printer, "__name__") and not hasattr(printer, "name"): | |
106 | raise TypeError("printer missing attribute: name") | |
107 | if hasattr(printer, "name") and not hasattr(printer, "enabled"): | |
108 | raise TypeError("printer missing attribute: enabled") | |
109 | if not hasattr(printer, "__call__"): | |
110 | raise TypeError("printer missing attribute: __call__") | |
111 | ||
112 | if obj is None: | |
113 | if gdb.parameter("verbose"): | |
114 | gdb.write("Registering global %s pretty-printer ...\n" % name) | |
115 | obj = gdb | |
116 | else: | |
117 | if gdb.parameter("verbose"): | |
118 | gdb.write("Registering %s pretty-printer for %s ...\n" % | |
119 | (printer.name, obj.filename)) | |
120 | ||
121 | if hasattr(printer, "name"): | |
122 | if not isinstance(printer.name, basestring): | |
123 | raise TypeError("printer name is not a string") | |
4e04c971 DE |
124 | # If printer provides a name, make sure it doesn't contain ";". |
125 | # Semicolon is used by the info/enable/disable pretty-printer commands | |
7b51bc51 | 126 | # to delimit subprinters. |
4e04c971 DE |
127 | if printer.name.find(";") >= 0: |
128 | raise ValueError("semicolon ';' in printer name") | |
7b51bc51 DE |
129 | # Also make sure the name is unique. |
130 | # Alas, we can't do the same for functions and __name__, they could | |
131 | # all have a canonical name like "lookup_function". | |
132 | # PERF: gdb records printers in a list, making this inefficient. | |
1fa57852 DE |
133 | i = 0 |
134 | for p in obj.pretty_printers: | |
135 | if hasattr(p, "name") and p.name == printer.name: | |
136 | if replace: | |
137 | del obj.pretty_printers[i] | |
138 | break | |
139 | else: | |
140 | raise RuntimeError("pretty-printer already registered: %s" % | |
141 | printer.name) | |
142 | i = i + 1 | |
7b51bc51 DE |
143 | |
144 | obj.pretty_printers.insert(0, printer) | |
145 | ||
146 | ||
147 | class RegexpCollectionPrettyPrinter(PrettyPrinter): | |
148 | """Class for implementing a collection of regular-expression based pretty-printers. | |
149 | ||
150 | Intended usage: | |
151 | ||
152 | pretty_printer = RegexpCollectionPrettyPrinter("my_library") | |
153 | pretty_printer.add_printer("myclass1", "^myclass1$", MyClass1Printer) | |
154 | ... | |
155 | pretty_printer.add_printer("myclassN", "^myclassN$", MyClassNPrinter) | |
156 | register_pretty_printer(obj, pretty_printer) | |
157 | """ | |
158 | ||
159 | class RegexpSubprinter(SubPrettyPrinter): | |
160 | def __init__(self, name, regexp, gen_printer): | |
161 | super(RegexpCollectionPrettyPrinter.RegexpSubprinter, self).__init__(name) | |
162 | self.regexp = regexp | |
163 | self.gen_printer = gen_printer | |
164 | self.compiled_re = re.compile(regexp) | |
165 | ||
166 | def __init__(self, name): | |
167 | super(RegexpCollectionPrettyPrinter, self).__init__(name, []) | |
168 | ||
169 | def add_printer(self, name, regexp, gen_printer): | |
170 | """Add a printer to the list. | |
171 | ||
172 | The printer is added to the end of the list. | |
173 | ||
174 | Arguments: | |
175 | name: The name of the subprinter. | |
176 | regexp: The regular expression, as a string. | |
177 | gen_printer: A function/method that given a value returns an | |
690a4937 | 178 | object to pretty-print it. |
7b51bc51 DE |
179 | |
180 | Returns: | |
181 | Nothing. | |
182 | """ | |
183 | ||
184 | # NOTE: A previous version made the name of each printer the regexp. | |
185 | # That makes it awkward to pass to the enable/disable commands (it's | |
186 | # cumbersome to make a regexp of a regexp). So now the name is a | |
187 | # separate parameter. | |
188 | ||
189 | self.subprinters.append(self.RegexpSubprinter(name, regexp, | |
190 | gen_printer)) | |
191 | ||
192 | def __call__(self, val): | |
193 | """Lookup the pretty-printer for the provided value.""" | |
194 | ||
195 | # Get the type name. | |
196 | typename = gdb.types.get_basic_type(val.type).tag | |
197 | if not typename: | |
198 | return None | |
199 | ||
200 | # Iterate over table of type regexps to determine | |
201 | # if a printer is registered for that type. | |
202 | # Return an instantiation of the printer if found. | |
203 | for printer in self.subprinters: | |
204 | if printer.enabled and printer.compiled_re.search(typename): | |
205 | return printer.gen_printer(val) | |
206 | ||
207 | # Cannot find a pretty printer. Return None. | |
208 | return None |