/usr/lib/python2.7/dist-packages/webassets/merge.py is in python-webassets 3:0.10.1-2.
This file is owned by root:root, with mode 0o644.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 | """Contains the core functionality that manages merging of assets.
"""
from __future__ import with_statement
import contextlib
try:
from urllib.request import Request as URLRequest, urlopen
from urllib.error import HTTPError
except ImportError:
from urllib2 import Request as URLRequest, urlopen
from urllib2 import HTTPError
import logging
from io import open
from webassets.six.moves import filter
from .utils import cmp_debug_levels, StringIO, hash_func
__all__ = ('FileHunk', 'MemoryHunk', 'merge', 'FilterTool',
'MoreThanOneFilterError', 'NoFilters')
# Log which is used to output low-level information about what the build does.
# This is setup such that it does not output just because the root level
# "webassets" logger is set to level DEBUG (for example via the commandline
# --verbose option). Instead, the messages are only shown when an environment
# variable is set.
# However, we might want to change this in the future. The CLI --verbose option
# could instead just set the level to NOTICE, for example.
log = logging.getLogger('webassets.debug')
log.addHandler(logging.StreamHandler())
import os
if os.environ.get('WEBASSETS_DEBUG'):
log.setLevel(logging.DEBUG)
else:
log.setLevel(logging.ERROR)
class BaseHunk(object):
"""Abstract base class.
"""
def mtime(self):
raise NotImplementedError()
def id(self):
return hash_func(self.data())
def __eq__(self, other):
if isinstance(other, BaseHunk):
# Allow class to be used as a unique dict key.
return hash_func(self) == hash_func(other)
return False
def data(self):
raise NotImplementedError()
def save(self, filename):
with open(filename, 'w') as f:
f.write(self.data())
class FileHunk(BaseHunk):
"""Exposes a single file through as a hunk.
"""
def __init__(self, filename):
self.filename = filename
def __repr__(self):
return '<%s %s>' % (self.__class__.__name__, self.filename)
def mtime(self):
pass
def data(self):
f = open(self.filename, 'r', encoding='utf-8')
try:
return f.read()
finally:
f.close()
class UrlHunk(BaseHunk):
"""Represents a file that is referenced by an Url.
If an environment is given, it's cache will be used to cache the url
contents, and to access it, as allowed by the etag/last modified headers.
"""
def __init__(self, url, env=None):
self.url = url
self.env = env
def __repr__(self):
return '<%s %s>' % (self.__class__.__name__, self.url)
def data(self):
if not hasattr(self, '_data'):
request = URLRequest(self.url)
# Look in the cache for etag / last modified headers to use
# TODO: "expires" header could be supported
if self.env and self.env.cache:
headers = self.env.cache.get(
('url', 'headers', self.url))
if headers:
etag, lmod = headers
if etag: request.add_header('If-None-Match', etag)
if lmod: request.add_header('If-Modified-Since', lmod)
# Make a request
try:
response = urlopen(request)
except HTTPError as e:
if e.code != 304:
raise
# Use the cached version of the url
self._data = self.env.cache.get(('url', 'contents', self.url))
else:
with contextlib.closing(response):
self._data = response.read()
# Cache the info from this request
if self.env and self.env.cache:
self.env.cache.set(
('url', 'headers', self.url),
(response.headers.getheader("ETag"),
response.headers.getheader("Last-Modified")))
self.env.cache.set(('url', 'contents', self.url), self._data)
return self._data
class MemoryHunk(BaseHunk):
"""Content that is no longer a direct representation of a source file. It
might have filters applied, and is probably the result of merging multiple
individual source files together.
"""
def __init__(self, data, files=None):
self._data = data
self.files = files or []
def __repr__(self):
# Include a has of the data. We want this during logging, so we
# can see which hunks contain identical content. Because this is
# a question of performance, make sure to log in such a way that
# when logging is disabled, this won't be called, i.e.: don't
# %s-format yourself, let logging do it as needed.
# TODO: Add a test to ensure this isn't called.
return '<%s %s>' % (self.__class__.__name__, hash_func(self.data))
def mtime(self):
pass
def data(self):
if hasattr(self._data, 'read'):
return self._data.read()
return self._data
def save(self, filename):
f = open(filename, 'w', encoding='utf-8')
try:
f.write(self.data())
finally:
f.close()
def merge(hunks, separator=None):
"""Merge the given list of hunks, returning a new ``MemoryHunk`` object.
"""
# TODO: combine the list of source files, we'd like to collect them
# The linebreak is important in certain cases for Javascript
# files, like when a last line is a //-comment.
if not separator:
separator = '\n'
return MemoryHunk(separator.join([h.data() for h in hunks]))
class MoreThanOneFilterError(Exception):
def __init__(self, message, filters):
Exception.__init__(self, message)
self.filters = filters
class NoFilters(Exception):
pass
class FilterTool(object):
"""Can apply filters to hunk objects, while using the cache.
If ``no_cache_read`` is given, then the cache will not be considered for
this operation (though the result will still be written to the cache).
``kwargs`` are options that should be passed along to the filters.
"""
VALID_TRANSFORMS = ('input', 'output',)
VALID_FUNCS = ('open', 'concat',)
def __init__(self, cache=None, no_cache_read=False, kwargs=None):
self.cache = cache
self.no_cache_read = no_cache_read
self.kwargs = kwargs or {}
def _wrap_cache(self, key, func):
"""Return cache value ``key``, or run ``func``.
"""
if self.cache:
if not self.no_cache_read:
log.debug('Checking cache for key %s', key)
content = self.cache.get(key)
if not content in (False, None):
log.debug('Using cached result for %s', key)
return MemoryHunk(content)
content = func().getvalue()
if self.cache:
log.debug('Storing result in cache with key %s', key,)
self.cache.set(key, content)
return MemoryHunk(content)
def apply(self, hunk, filters, type, kwargs=None):
"""Apply the given list of filters to the hunk, returning a new
``MemoryHunk`` object.
``kwargs`` are options that should be passed along to the filters.
If ``hunk`` is a file hunk, a ``source_path`` key will automatically
be added to ``kwargs``.
"""
assert type in self.VALID_TRANSFORMS
log.debug('Need to run method "%s" of filters (%s) on hunk %s with '
'kwargs=%s', type, filters, hunk, kwargs)
filters = [f for f in filters if getattr(f, type, None)]
if not filters: # Short-circuit
log.debug('No filters have "%s" methods, returning hunk '
'unchanged' % (type,))
return hunk
kwargs_final = self.kwargs.copy()
kwargs_final.update(kwargs or {})
def func():
data = StringIO(hunk.data())
for filter in filters:
log.debug('Running method "%s" of %s with kwargs=%s',
type, filter, kwargs_final)
out = StringIO(u'') # For 2.x, StringIO().getvalue() returns str
getattr(filter, type)(data, out, **kwargs_final)
data = out
data.seek(0)
return data
additional_cache_keys = []
if kwargs_final:
for filter in filters:
additional_cache_keys += filter.get_additional_cache_keys(**kwargs_final)
# Note that the key used to cache this hunk is different from the key
# the hunk will expose to subsequent merges, i.e. hunk.key() is always
# based on the actual content, and does not match the cache key. The
# latter also includes information about for example the filters used.
#
# It wouldn't have to be this way. Hunk could subsequently expose their
# cache key through hunk.key(). This would work as well, but would be
# an inferior solution: Imagine a source file which receives
# non-substantial changes, in the sense that they do not affect the
# filter output, for example whitespace. If a hunk's key is the cache
# key, such a change would invalidate the caches for all subsequent
# operations on this hunk as well, even though it didn't actually
# change after all.
key = ("hunk", hunk, tuple(filters), type, additional_cache_keys)
return self._wrap_cache(key, func)
def apply_func(self, filters, type, args, kwargs=None, cache_key=None):
"""Apply a filter that is not a "stream in, stream out" transform (i.e.
like the input() and output() filter methods). Instead, the filter
method is given the arguments in ``args`` and should then produce an
output stream. This is used, e.g., for the concat() and open() filter
methods.
Only one such filter can run per operation.
``cache_key`` may be a list of additional values to use as the cache
key, in addition to the default key (the filter and arguments).
"""
assert type in self.VALID_FUNCS
log.debug('Need to run method "%s" of one of the filters (%s) '
'with args=%s, kwargs=%s', type, filters, args, kwargs)
filters = [f for f in filters if getattr(f, type, None)]
if not filters: # Short-circuit
log.debug('No filters have a "%s" method' % type)
raise NoFilters()
if len(filters) > 1:
raise MoreThanOneFilterError(
'These filters cannot be combined: %s' % (
', '.join([f.name for f in filters])), filters)
kwargs_final = self.kwargs.copy()
kwargs_final.update(kwargs or {})
def func():
filter = filters[0]
out = StringIO(u'') # For 2.x, StringIO().getvalue() returns str
log.debug('Running method "%s" of %s with args=%s, kwargs=%s',
type, filter, args, kwargs)
getattr(filter, type)(out, *args, **kwargs_final)
return out
additional_cache_keys = []
if kwargs_final:
for filter in filters:
additional_cache_keys += filter.get_additional_cache_keys(**kwargs_final)
key = ("hunk", args, tuple(filters), type, cache_key or [], additional_cache_keys)
return self._wrap_cache(key, func)
def merge_filters(filters1, filters2):
"""Merge two filter lists into one.
Duplicate filters are removed. Since filter order is important, the order
of the arguments to this function also matter. Duplicates are always
removed from the second filter set if they exist in the first.
The result will always be ``filters1``, with additional unique filters
from ``filters2`` appended. Within the context of a hierarchy, you want
``filters2`` to be the parent.
This function presumes that all the given filters inherit from ``Filter``,
which properly implements operators to determine duplicate filters.
"""
result = list(filters1[:])
if filters2:
for f in filters2:
if not f in result:
result.append(f)
return result
def select_filters(filters, level):
"""Return from the list in ``filters`` those filters which indicate that
they should run for the given debug level.
"""
return [f for f in filters
if f.max_debug_level is None or
cmp_debug_levels(level, f.max_debug_level) <= 0]
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