4763.2.4
by John Arbash Meinel
merge bzr.2.1 in preparation for NEWS entry. |
1 |
# Copyright (C) 2006-2010 Canonical Ltd
|
1887.1.1
by Adeodato Simó
Do not separate paragraphs in the copyright statement with blank lines, |
2 |
#
|
1185.70.3
by Martin Pool
Various updates to make storage branch mergeable: |
3 |
# This program is free software; you can redistribute it and/or modify
|
4 |
# it under the terms of the GNU General Public License as published by
|
|
5 |
# the Free Software Foundation; either version 2 of the License, or
|
|
6 |
# (at your option) any later version.
|
|
7 |
#
|
|
8 |
# This program is distributed in the hope that it will be useful,
|
|
9 |
# but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
10 |
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
11 |
# GNU General Public License for more details.
|
|
1887.1.1
by Adeodato Simó
Do not separate paragraphs in the copyright statement with blank lines, |
12 |
#
|
1185.70.3
by Martin Pool
Various updates to make storage branch mergeable: |
13 |
# You should have received a copy of the GNU General Public License
|
14 |
# along with this program; if not, write to the Free Software
|
|
4183.7.1
by Sabin Iacob
update FSF mailing address |
15 |
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
1185.70.3
by Martin Pool
Various updates to make storage branch mergeable: |
16 |
|
17 |
||
1185.65.27
by Robert Collins
Tweak storage towards mergability. |
18 |
__all__ = ['needs_read_lock', |
19 |
'needs_write_lock', |
|
2230.2.4
by John Arbash Meinel
Add tests that decorators generate useful wrappers. |
20 |
'use_fast_decorators', |
21 |
'use_pretty_decorators', |
|
1185.65.27
by Robert Collins
Tweak storage towards mergability. |
22 |
]
|
23 |
||
2230.2.2
by John Arbash Meinel
Change decorators to define the same parameters as the wrapped func. |
24 |
|
3316.3.1
by Andrew Bennetts
Try not to lose the original exception in needs_write_lock decorator if the unlock raises a secondary exception. |
25 |
import sys |
26 |
||
4634.85.9
by Andrew Bennetts
Add some experimental decorators: @only_raises(..) and @cleanup_method. |
27 |
from bzrlib import trace |
28 |
||
3316.3.1
by Andrew Bennetts
Try not to lose the original exception in needs_write_lock decorator if the unlock raises a secondary exception. |
29 |
|
2230.2.2
by John Arbash Meinel
Change decorators to define the same parameters as the wrapped func. |
30 |
def _get_parameters(func): |
31 |
"""Recreate the parameters for a function using introspection.
|
|
32 |
||
2230.2.6
by John Arbash Meinel
Clean up the documentation and imports for decorators (per Martin's suggestions) |
33 |
:return: (function_params, calling_params)
|
34 |
function_params: is a string representing the parameters of the
|
|
35 |
function. (such as "a, b, c=None, d=1")
|
|
36 |
This is used in the function declaration.
|
|
37 |
calling_params: is another string representing how you would call the
|
|
38 |
function with the correct parameters. (such as "a, b, c=c, d=d")
|
|
39 |
Assuming you sued function_params in the function declaration, this
|
|
40 |
is the parameters to put in the function call.
|
|
41 |
||
42 |
For example:
|
|
43 |
||
44 |
def wrapper(%(function_params)s):
|
|
45 |
return original(%(calling_params)s)
|
|
2230.2.2
by John Arbash Meinel
Change decorators to define the same parameters as the wrapped func. |
46 |
"""
|
2230.2.6
by John Arbash Meinel
Clean up the documentation and imports for decorators (per Martin's suggestions) |
47 |
# "import inspect" should stay in local scope. 'inspect' takes a long time
|
48 |
# to import the first time. And since we don't always need it, don't import
|
|
49 |
# it globally.
|
|
50 |
import inspect |
|
51 |
args, varargs, varkw, defaults = inspect.getargspec(func) |
|
52 |
formatted = inspect.formatargspec(args, varargs=varargs, |
|
53 |
varkw=varkw, |
|
54 |
defaults=defaults) |
|
2230.2.2
by John Arbash Meinel
Change decorators to define the same parameters as the wrapped func. |
55 |
if defaults is None: |
56 |
args_passed = args |
|
57 |
else: |
|
58 |
first_default = len(args) - len(defaults) |
|
59 |
args_passed = args[:first_default] |
|
60 |
for arg in args[first_default:]: |
|
61 |
args_passed.append("%s=%s" % (arg, arg)) |
|
62 |
if varargs is not None: |
|
63 |
args_passed.append('*' + varargs) |
|
64 |
if varkw is not None: |
|
65 |
args_passed.append('**' + varkw) |
|
66 |
args_passed = ', '.join(args_passed) |
|
67 |
||
68 |
return formatted[1:-1], args_passed |
|
69 |
||
70 |
||
2230.2.3
by John Arbash Meinel
Add the ability to have fast decorators as well as pretty ones, and have 'bzr' select the right one at startup. |
71 |
def _pretty_needs_read_lock(unbound): |
1185.70.3
by Martin Pool
Various updates to make storage branch mergeable: |
72 |
"""Decorate unbound to take out and release a read lock.
|
73 |
||
74 |
This decorator can be applied to methods of any class with lock_read() and
|
|
75 |
unlock() methods.
|
|
3943.8.1
by Marius Kruger
remove all trailing whitespace from bzr source |
76 |
|
1185.70.3
by Martin Pool
Various updates to make storage branch mergeable: |
77 |
Typical usage:
|
3943.8.1
by Marius Kruger
remove all trailing whitespace from bzr source |
78 |
|
1185.70.3
by Martin Pool
Various updates to make storage branch mergeable: |
79 |
class Branch(...):
|
80 |
@needs_read_lock
|
|
81 |
def branch_method(self, ...):
|
|
82 |
stuff
|
|
83 |
"""
|
|
2230.2.2
by John Arbash Meinel
Change decorators to define the same parameters as the wrapped func. |
84 |
# This compiles a function with a similar name, but wrapped with
|
85 |
# lock_read/unlock calls. We use dynamic creation, because we need the
|
|
86 |
# internal name of the function to be modified so that --lsprof will see
|
|
87 |
# the correct name.
|
|
88 |
# TODO: jam 20070111 Modify this template so that the generated function
|
|
89 |
# has the same argument signature as the original function, which
|
|
90 |
# will help commands like epydoc.
|
|
91 |
# This seems possible by introspecting foo.func_defaults, and
|
|
92 |
# foo.func_code.co_argcount and foo.func_code.co_varnames
|
|
2230.2.1
by John Arbash Meinel
Change the read_lock and write_lock decorators to use custom names |
93 |
template = """\ |
2230.2.2
by John Arbash Meinel
Change decorators to define the same parameters as the wrapped func. |
94 |
def %(name)s_read_locked(%(params)s): |
2230.2.1
by John Arbash Meinel
Change the read_lock and write_lock decorators to use custom names |
95 |
self.lock_read()
|
96 |
try:
|
|
3316.3.2
by John Arbash Meinel
Finish fix for bug #125784. need_read/write_lock decorators should attempt to raise an original exception. |
97 |
result = unbound(%(passed_params)s) |
98 |
except:
|
|
99 |
import sys
|
|
100 |
exc_info = sys.exc_info()
|
|
101 |
try:
|
|
102 |
self.unlock()
|
|
103 |
finally:
|
|
104 |
raise exc_info[0], exc_info[1], exc_info[2]
|
|
105 |
else:
|
|
2230.2.1
by John Arbash Meinel
Change the read_lock and write_lock decorators to use custom names |
106 |
self.unlock()
|
3316.3.2
by John Arbash Meinel
Finish fix for bug #125784. need_read/write_lock decorators should attempt to raise an original exception. |
107 |
return result
|
2230.2.1
by John Arbash Meinel
Change the read_lock and write_lock decorators to use custom names |
108 |
read_locked = %(name)s_read_locked |
109 |
"""
|
|
2230.2.2
by John Arbash Meinel
Change decorators to define the same parameters as the wrapped func. |
110 |
params, passed_params = _get_parameters(unbound) |
111 |
variables = {'name':unbound.__name__, |
|
112 |
'params':params, |
|
113 |
'passed_params':passed_params, |
|
114 |
}
|
|
115 |
func_def = template % variables |
|
116 |
||
2230.2.1
by John Arbash Meinel
Change the read_lock and write_lock decorators to use custom names |
117 |
exec func_def in locals() |
118 |
||
1534.4.48
by Robert Collins
Make needs_read_lock and needs_write_lock more visible in tracebacks |
119 |
read_locked.__doc__ = unbound.__doc__ |
120 |
read_locked.__name__ = unbound.__name__ |
|
121 |
return read_locked |
|
1185.70.3
by Martin Pool
Various updates to make storage branch mergeable: |
122 |
|
123 |
||
2230.2.3
by John Arbash Meinel
Add the ability to have fast decorators as well as pretty ones, and have 'bzr' select the right one at startup. |
124 |
def _fast_needs_read_lock(unbound): |
125 |
"""Decorate unbound to take out and release a read lock.
|
|
126 |
||
127 |
This decorator can be applied to methods of any class with lock_read() and
|
|
128 |
unlock() methods.
|
|
3943.8.1
by Marius Kruger
remove all trailing whitespace from bzr source |
129 |
|
2230.2.3
by John Arbash Meinel
Add the ability to have fast decorators as well as pretty ones, and have 'bzr' select the right one at startup. |
130 |
Typical usage:
|
3943.8.1
by Marius Kruger
remove all trailing whitespace from bzr source |
131 |
|
2230.2.3
by John Arbash Meinel
Add the ability to have fast decorators as well as pretty ones, and have 'bzr' select the right one at startup. |
132 |
class Branch(...):
|
133 |
@needs_read_lock
|
|
134 |
def branch_method(self, ...):
|
|
135 |
stuff
|
|
136 |
"""
|
|
137 |
def read_locked(self, *args, **kwargs): |
|
138 |
self.lock_read() |
|
139 |
try: |
|
3316.3.2
by John Arbash Meinel
Finish fix for bug #125784. need_read/write_lock decorators should attempt to raise an original exception. |
140 |
result = unbound(self, *args, **kwargs) |
141 |
except: |
|
142 |
import sys |
|
143 |
exc_info = sys.exc_info() |
|
144 |
try: |
|
145 |
self.unlock() |
|
146 |
finally: |
|
147 |
raise exc_info[0], exc_info[1], exc_info[2] |
|
148 |
else: |
|
2230.2.3
by John Arbash Meinel
Add the ability to have fast decorators as well as pretty ones, and have 'bzr' select the right one at startup. |
149 |
self.unlock() |
3316.3.2
by John Arbash Meinel
Finish fix for bug #125784. need_read/write_lock decorators should attempt to raise an original exception. |
150 |
return result |
2230.2.3
by John Arbash Meinel
Add the ability to have fast decorators as well as pretty ones, and have 'bzr' select the right one at startup. |
151 |
read_locked.__doc__ = unbound.__doc__ |
152 |
read_locked.__name__ = unbound.__name__ |
|
153 |
return read_locked |
|
154 |
||
155 |
||
156 |
def _pretty_needs_write_lock(unbound): |
|
1185.70.3
by Martin Pool
Various updates to make storage branch mergeable: |
157 |
"""Decorate unbound to take out and release a write lock."""
|
2230.2.1
by John Arbash Meinel
Change the read_lock and write_lock decorators to use custom names |
158 |
template = """\ |
2230.2.2
by John Arbash Meinel
Change decorators to define the same parameters as the wrapped func. |
159 |
def %(name)s_write_locked(%(params)s): |
2230.2.1
by John Arbash Meinel
Change the read_lock and write_lock decorators to use custom names |
160 |
self.lock_write()
|
161 |
try:
|
|
3316.3.2
by John Arbash Meinel
Finish fix for bug #125784. need_read/write_lock decorators should attempt to raise an original exception. |
162 |
result = unbound(%(passed_params)s) |
3316.3.1
by Andrew Bennetts
Try not to lose the original exception in needs_write_lock decorator if the unlock raises a secondary exception. |
163 |
except:
|
3316.3.2
by John Arbash Meinel
Finish fix for bug #125784. need_read/write_lock decorators should attempt to raise an original exception. |
164 |
import sys
|
3316.3.1
by Andrew Bennetts
Try not to lose the original exception in needs_write_lock decorator if the unlock raises a secondary exception. |
165 |
exc_info = sys.exc_info()
|
166 |
try:
|
|
167 |
self.unlock()
|
|
168 |
finally:
|
|
169 |
raise exc_info[0], exc_info[1], exc_info[2]
|
|
170 |
else:
|
|
2230.2.1
by John Arbash Meinel
Change the read_lock and write_lock decorators to use custom names |
171 |
self.unlock()
|
3316.3.1
by Andrew Bennetts
Try not to lose the original exception in needs_write_lock decorator if the unlock raises a secondary exception. |
172 |
return result
|
2230.2.1
by John Arbash Meinel
Change the read_lock and write_lock decorators to use custom names |
173 |
write_locked = %(name)s_write_locked |
174 |
"""
|
|
2230.2.2
by John Arbash Meinel
Change decorators to define the same parameters as the wrapped func. |
175 |
params, passed_params = _get_parameters(unbound) |
176 |
variables = {'name':unbound.__name__, |
|
177 |
'params':params, |
|
178 |
'passed_params':passed_params, |
|
179 |
}
|
|
180 |
func_def = template % variables |
|
181 |
||
2230.2.1
by John Arbash Meinel
Change the read_lock and write_lock decorators to use custom names |
182 |
exec func_def in locals() |
183 |
||
1534.4.48
by Robert Collins
Make needs_read_lock and needs_write_lock more visible in tracebacks |
184 |
write_locked.__doc__ = unbound.__doc__ |
185 |
write_locked.__name__ = unbound.__name__ |
|
186 |
return write_locked |
|
1185.70.3
by Martin Pool
Various updates to make storage branch mergeable: |
187 |
|
2230.2.3
by John Arbash Meinel
Add the ability to have fast decorators as well as pretty ones, and have 'bzr' select the right one at startup. |
188 |
|
189 |
def _fast_needs_write_lock(unbound): |
|
190 |
"""Decorate unbound to take out and release a write lock."""
|
|
191 |
def write_locked(self, *args, **kwargs): |
|
192 |
self.lock_write() |
|
193 |
try: |
|
3316.3.1
by Andrew Bennetts
Try not to lose the original exception in needs_write_lock decorator if the unlock raises a secondary exception. |
194 |
result = unbound(self, *args, **kwargs) |
195 |
except: |
|
196 |
exc_info = sys.exc_info() |
|
197 |
try: |
|
198 |
self.unlock() |
|
199 |
finally: |
|
200 |
raise exc_info[0], exc_info[1], exc_info[2] |
|
201 |
else: |
|
2230.2.3
by John Arbash Meinel
Add the ability to have fast decorators as well as pretty ones, and have 'bzr' select the right one at startup. |
202 |
self.unlock() |
3316.3.1
by Andrew Bennetts
Try not to lose the original exception in needs_write_lock decorator if the unlock raises a secondary exception. |
203 |
return result |
2230.2.3
by John Arbash Meinel
Add the ability to have fast decorators as well as pretty ones, and have 'bzr' select the right one at startup. |
204 |
write_locked.__doc__ = unbound.__doc__ |
205 |
write_locked.__name__ = unbound.__name__ |
|
206 |
return write_locked |
|
207 |
||
208 |
||
4634.85.9
by Andrew Bennetts
Add some experimental decorators: @only_raises(..) and @cleanup_method. |
209 |
def only_raises(*errors): |
4634.62.2
by Andrew Bennetts
Update test_decorators, add docstring. |
210 |
"""Make a decorator that will only allow the given error classes to be
|
211 |
raised. All other errors will be logged and then discarded.
|
|
212 |
||
213 |
Typical use is something like::
|
|
214 |
||
215 |
@only_raises(LockNotHeld, LockBroken)
|
|
216 |
def unlock(self):
|
|
217 |
# etc
|
|
218 |
"""
|
|
4634.85.9
by Andrew Bennetts
Add some experimental decorators: @only_raises(..) and @cleanup_method. |
219 |
def decorator(unbound): |
220 |
def wrapped(*args, **kwargs): |
|
221 |
try: |
|
222 |
return unbound(*args, **kwargs) |
|
223 |
except errors: |
|
224 |
raise
|
|
225 |
except: |
|
226 |
trace.mutter('Error suppressed by only_raises:') |
|
227 |
trace.log_exception_quietly() |
|
228 |
wrapped.__doc__ = unbound.__doc__ |
|
229 |
wrapped.__name__ = unbound.__name__ |
|
230 |
return wrapped |
|
231 |
return decorator |
|
232 |
||
233 |
||
2230.2.3
by John Arbash Meinel
Add the ability to have fast decorators as well as pretty ones, and have 'bzr' select the right one at startup. |
234 |
# Default is more functionality, 'bzr' the commandline will request fast
|
235 |
# versions.
|
|
236 |
needs_read_lock = _pretty_needs_read_lock |
|
237 |
needs_write_lock = _pretty_needs_write_lock |
|
238 |
||
239 |
||
240 |
def use_fast_decorators(): |
|
241 |
"""Change the default decorators to be fast loading ones.
|
|
242 |
||
243 |
The alternative is to have decorators that do more work to produce
|
|
244 |
nice-looking decorated functions, but this slows startup time.
|
|
245 |
"""
|
|
246 |
global needs_read_lock, needs_write_lock |
|
247 |
needs_read_lock = _fast_needs_read_lock |
|
248 |
needs_write_lock = _fast_needs_write_lock |
|
249 |
||
250 |
||
251 |
def use_pretty_decorators(): |
|
252 |
"""Change the default decorators to be pretty ones."""
|
|
253 |
global needs_read_lock, needs_write_lock |
|
254 |
needs_read_lock = _pretty_needs_read_lock |
|
255 |
needs_write_lock = _pretty_needs_write_lock |
|
4869.3.13
by Andrew Bennetts
Add simple cachedproperty decorator, and add {this,other,base}_lines cachedproperties to MergeHookParams. |
256 |
|
257 |
||
4869.3.32
by Andrew Bennetts
Use Launchpad's cachedproperty decorator instead of my stupidly broken one. |
258 |
# This implementation of cachedproperty is copied from Launchpad's
|
4869.3.34
by Vincent Ladeuil
Finish the patch based on reviews. |
259 |
# canonical.launchpad.cachedproperty module (with permission from flacoste)
|
260 |
# -- spiv & vila 100120
|
|
4869.3.32
by Andrew Bennetts
Use Launchpad's cachedproperty decorator instead of my stupidly broken one. |
261 |
def cachedproperty(attrname_or_fn): |
262 |
"""A decorator for methods that makes them properties with their return
|
|
263 |
value cached.
|
|
264 |
||
265 |
The value is cached on the instance, using the attribute name provided.
|
|
266 |
||
267 |
If you don't provide a name, the mangled name of the property is used.
|
|
268 |
||
269 |
>>> class CachedPropertyTest(object):
|
|
270 |
...
|
|
271 |
... @cachedproperty('_foo_cache')
|
|
272 |
... def foo(self):
|
|
273 |
... print 'foo computed'
|
|
274 |
... return 23
|
|
275 |
...
|
|
276 |
... @cachedproperty
|
|
277 |
... def bar(self):
|
|
278 |
... print 'bar computed'
|
|
279 |
... return 69
|
|
280 |
||
281 |
>>> cpt = CachedPropertyTest()
|
|
282 |
>>> getattr(cpt, '_foo_cache', None) is None
|
|
283 |
True
|
|
284 |
>>> cpt.foo
|
|
285 |
foo computed
|
|
286 |
23
|
|
287 |
>>> cpt.foo
|
|
288 |
23
|
|
289 |
>>> cpt._foo_cache
|
|
290 |
23
|
|
291 |
>>> cpt.bar
|
|
292 |
bar computed
|
|
293 |
69
|
|
294 |
>>> cpt._bar_cached_value
|
|
295 |
69
|
|
296 |
||
4869.3.13
by Andrew Bennetts
Add simple cachedproperty decorator, and add {this,other,base}_lines cachedproperties to MergeHookParams. |
297 |
"""
|
4869.3.32
by Andrew Bennetts
Use Launchpad's cachedproperty decorator instead of my stupidly broken one. |
298 |
if isinstance(attrname_or_fn, basestring): |
299 |
attrname = attrname_or_fn |
|
300 |
return _CachedPropertyForAttr(attrname) |
|
301 |
else: |
|
302 |
fn = attrname_or_fn |
|
303 |
attrname = '_%s_cached_value' % fn.__name__ |
|
304 |
return _CachedProperty(attrname, fn) |
|
305 |
||
306 |
||
307 |
class _CachedPropertyForAttr(object): |
|
308 |
||
309 |
def __init__(self, attrname): |
|
310 |
self.attrname = attrname |
|
311 |
||
312 |
def __call__(self, fn): |
|
313 |
return _CachedProperty(self.attrname, fn) |
|
314 |
||
315 |
||
316 |
class _CachedProperty(object): |
|
317 |
||
318 |
def __init__(self, attrname, fn): |
|
319 |
self.fn = fn |
|
320 |
self.attrname = attrname |
|
321 |
self.marker = object() |
|
322 |
||
323 |
def __get__(self, inst, cls=None): |
|
324 |
if inst is None: |
|
325 |
return self |
|
326 |
cachedresult = getattr(inst, self.attrname, self.marker) |
|
327 |
if cachedresult is self.marker: |
|
328 |
result = self.fn(inst) |
|
329 |
setattr(inst, self.attrname, result) |
|
330 |
return result |
|
331 |
else: |
|
332 |
return cachedresult |