qapi script: add event support
[qemu.git] / scripts / tracetool / __init__.py
1 #!/usr/bin/env python
2 # -*- coding: utf-8 -*-
3
4 """
5 Machinery for generating tracing-related intermediate files.
6 """
7
8 __author__ = "Lluís Vilanova <vilanova@ac.upc.edu>"
9 __copyright__ = "Copyright 2012-2014, Lluís Vilanova <vilanova@ac.upc.edu>"
10 __license__ = "GPL version 2 or (at your option) any later version"
11
12 __maintainer__ = "Stefan Hajnoczi"
13 __email__ = "stefanha@linux.vnet.ibm.com"
14
15
16 import re
17 import sys
18
19 import tracetool.format
20 import tracetool.backend
21
22
23 def error_write(*lines):
24 """Write a set of error lines."""
25 sys.stderr.writelines("\n".join(lines) + "\n")
26
27 def error(*lines):
28 """Write a set of error lines and exit."""
29 error_write(*lines)
30 sys.exit(1)
31
32
33 def out(*lines, **kwargs):
34 """Write a set of output lines.
35
36 You can use kwargs as a shorthand for mapping variables when formating all
37 the strings in lines.
38 """
39 lines = [ l % kwargs for l in lines ]
40 sys.stdout.writelines("\n".join(lines) + "\n")
41
42
43 class Arguments:
44 """Event arguments description."""
45
46 def __init__(self, args):
47 """
48 Parameters
49 ----------
50 args :
51 List of (type, name) tuples.
52 """
53 self._args = args
54
55 def copy(self):
56 """Create a new copy."""
57 return Arguments(list(self._args))
58
59 @staticmethod
60 def build(arg_str):
61 """Build and Arguments instance from an argument string.
62
63 Parameters
64 ----------
65 arg_str : str
66 String describing the event arguments.
67 """
68 res = []
69 for arg in arg_str.split(","):
70 arg = arg.strip()
71 if arg == 'void':
72 continue
73
74 if '*' in arg:
75 arg_type, identifier = arg.rsplit('*', 1)
76 arg_type += '*'
77 identifier = identifier.strip()
78 else:
79 arg_type, identifier = arg.rsplit(None, 1)
80
81 res.append((arg_type, identifier))
82 return Arguments(res)
83
84 def __iter__(self):
85 """Iterate over the (type, name) pairs."""
86 return iter(self._args)
87
88 def __len__(self):
89 """Number of arguments."""
90 return len(self._args)
91
92 def __str__(self):
93 """String suitable for declaring function arguments."""
94 if len(self._args) == 0:
95 return "void"
96 else:
97 return ", ".join([ " ".join([t, n]) for t,n in self._args ])
98
99 def __repr__(self):
100 """Evaluable string representation for this object."""
101 return "Arguments(\"%s\")" % str(self)
102
103 def names(self):
104 """List of argument names."""
105 return [ name for _, name in self._args ]
106
107 def types(self):
108 """List of argument types."""
109 return [ type_ for type_, _ in self._args ]
110
111
112 class Event(object):
113 """Event description.
114
115 Attributes
116 ----------
117 name : str
118 The event name.
119 fmt : str
120 The event format string.
121 properties : set(str)
122 Properties of the event.
123 args : Arguments
124 The event arguments.
125 """
126
127 _CRE = re.compile("((?P<props>.*)\s+)?(?P<name>[^(\s]+)\((?P<args>[^)]*)\)\s*(?P<fmt>\".*)?")
128
129 _VALID_PROPS = set(["disable"])
130
131 def __init__(self, name, props, fmt, args):
132 """
133 Parameters
134 ----------
135 name : string
136 Event name.
137 props : list of str
138 Property names.
139 fmt : str
140 Event printing format.
141 args : Arguments
142 Event arguments.
143 """
144 self.name = name
145 self.properties = props
146 self.fmt = fmt
147 self.args = args
148
149 unknown_props = set(self.properties) - self._VALID_PROPS
150 if len(unknown_props) > 0:
151 raise ValueError("Unknown properties: %s"
152 % ", ".join(unknown_props))
153
154 def copy(self):
155 """Create a new copy."""
156 return Event(self.name, list(self.properties), self.fmt,
157 self.args.copy(), self)
158
159 @staticmethod
160 def build(line_str):
161 """Build an Event instance from a string.
162
163 Parameters
164 ----------
165 line_str : str
166 Line describing the event.
167 """
168 m = Event._CRE.match(line_str)
169 assert m is not None
170 groups = m.groupdict('')
171
172 name = groups["name"]
173 props = groups["props"].split()
174 fmt = groups["fmt"]
175 args = Arguments.build(groups["args"])
176
177 return Event(name, props, fmt, args)
178
179 def __repr__(self):
180 """Evaluable string representation for this object."""
181 return "Event('%s %s(%s) %s')" % (" ".join(self.properties),
182 self.name,
183 self.args,
184 self.fmt)
185
186 QEMU_TRACE = "trace_%(name)s"
187
188 def api(self, fmt=None):
189 if fmt is None:
190 fmt = Event.QEMU_TRACE
191 return fmt % {"name": self.name}
192
193
194 def _read_events(fobj):
195 res = []
196 for line in fobj:
197 if not line.strip():
198 continue
199 if line.lstrip().startswith('#'):
200 continue
201 res.append(Event.build(line))
202 return res
203
204
205 class TracetoolError (Exception):
206 """Exception for calls to generate."""
207 pass
208
209
210 def try_import(mod_name, attr_name=None, attr_default=None):
211 """Try to import a module and get an attribute from it.
212
213 Parameters
214 ----------
215 mod_name : str
216 Module name.
217 attr_name : str, optional
218 Name of an attribute in the module.
219 attr_default : optional
220 Default value if the attribute does not exist in the module.
221
222 Returns
223 -------
224 A pair indicating whether the module could be imported and the module or
225 object or attribute value.
226 """
227 try:
228 module = __import__(mod_name, globals(), locals(), ["__package__"])
229 if attr_name is None:
230 return True, module
231 return True, getattr(module, str(attr_name), attr_default)
232 except ImportError:
233 return False, None
234
235
236 def generate(fevents, format, backends,
237 binary=None, probe_prefix=None):
238 """Generate the output for the given (format, backends) pair.
239
240 Parameters
241 ----------
242 fevents : file
243 Event description file.
244 format : str
245 Output format name.
246 backends : list
247 Output backend names.
248 binary : str or None
249 See tracetool.backend.dtrace.BINARY.
250 probe_prefix : str or None
251 See tracetool.backend.dtrace.PROBEPREFIX.
252 """
253 # fix strange python error (UnboundLocalError tracetool)
254 import tracetool
255
256 format = str(format)
257 if len(format) is 0:
258 raise TracetoolError("format not set")
259 if not tracetool.format.exists(format):
260 raise TracetoolError("unknown format: %s" % format)
261
262 if len(backends) is 0:
263 raise TracetoolError("no backends specified")
264 for backend in backends:
265 if not tracetool.backend.exists(backend):
266 raise TracetoolError("unknown backend: %s" % backend)
267 backend = tracetool.backend.Wrapper(backends, format)
268
269 import tracetool.backend.dtrace
270 tracetool.backend.dtrace.BINARY = binary
271 tracetool.backend.dtrace.PROBEPREFIX = probe_prefix
272
273 events = _read_events(fevents)
274
275 tracetool.format.generate(events, format, backend)