The Tor Browser / file revision

 # This Source Code Form is subject to the terms of the Mozilla Public

 # License, v. 2.0. If a copy of the MPL was not distributed with this

 # file, You can obtain one at http://mozilla.org/MPL/2.0/.

 import errno

 import os

 import platform

 import shutil

 import stat

 import subprocess

 import uuid

 import mozbuild.makeutil as makeutil

 from mozbuild.preprocessor import Preprocessor

 from mozbuild.util import FileAvoidWrite

 from mozpack.executables import (

     is_executable,

     may_strip,

     strip,

     may_elfhack,

     elfhack,

 )

 from mozpack.chrome.manifest import ManifestEntry

 from io import BytesIO

 from mozpack.errors import (

     ErrorMessage,

     errors,

 )

 from mozpack.mozjar import JarReader

 import mozpack.path

 from collections import OrderedDict

 from jsmin import JavascriptMinify

 from tempfile import (

     mkstemp,

     NamedTemporaryFile,

 )

 class Dest(object):

     '''

     Helper interface for BaseFile.copy. The interface works as follows:

     - read() and write() can be used to sequentially read/write from the

       underlying file.

     - a call to read() after a write() will re-open the underlying file and

       read from it.

     - a call to write() after a read() will re-open the underlying file,

       emptying it, and write to it.

     '''

     def __init__(self, path):

         self.path = path

         self.mode = None

     @property

     def name(self):

         return self.path

     def read(self, length=-1):

         if self.mode != 'r':

             self.file = open(self.path, 'rb')

             self.mode = 'r'

         return self.file.read(length)

     def write(self, data):

         if self.mode != 'w':

             self.file = open(self.path, 'wb')

             self.mode = 'w'

         return self.file.write(data)

     def exists(self):

         return os.path.exists(self.path)

     def close(self):

         if self.mode:

             self.mode = None

             self.file.close()

 class BaseFile(object):

     '''

     Base interface and helper for file copying. Derived class may implement

     their own copy function, or rely on BaseFile.copy using the open() member

     function and/or the path property.

     '''

     @staticmethod

     def is_older(first, second):

         '''

         Compares the modification time of two files, and returns whether the

         ``first`` file is older than the ``second`` file.

         '''

         # os.path.getmtime returns a result in seconds with precision up to

         # the microsecond. But microsecond is too precise because

         # shutil.copystat only copies milliseconds, and seconds is not

         # enough precision.

         return int(os.path.getmtime(first) * 1000) \

                 <= int(os.path.getmtime(second) * 1000)

     @staticmethod

     def any_newer(dest, inputs):

         '''

         Compares the modification time of ``dest`` to multiple input files, and

         returns whether any of the ``inputs`` is newer (has a later mtime) than

         ``dest``.

         '''

         # os.path.getmtime returns a result in seconds with precision up to

         # the microsecond. But microsecond is too precise because

         # shutil.copystat only copies milliseconds, and seconds is not

         # enough precision.

         dest_mtime = int(os.path.getmtime(dest) * 1000)

         for input in inputs:

             if dest_mtime < int(os.path.getmtime(input) * 1000):

                 return True

         return False

     def copy(self, dest, skip_if_older=True):

         '''

         Copy the BaseFile content to the destination given as a string or a

         Dest instance. Avoids replacing existing files if the BaseFile content

         matches that of the destination, or in case of plain files, if the

         destination is newer than the original file. This latter behaviour is

         disabled when skip_if_older is False.

         Returns whether a copy was actually performed (True) or not (False).

         '''

         if isinstance(dest, basestring):

             dest = Dest(dest)

         else:

             assert isinstance(dest, Dest)

         can_skip_content_check = False

         if not dest.exists():

             can_skip_content_check = True

         elif getattr(self, 'path', None) and getattr(dest, 'path', None):

             if skip_if_older and BaseFile.is_older(self.path, dest.path):

                 return False

             elif os.path.getsize(self.path) != os.path.getsize(dest.path):

                 can_skip_content_check = True

         if can_skip_content_check:

             if getattr(self, 'path', None) and getattr(dest, 'path', None):

                 shutil.copy2(self.path, dest.path)

             else:

                 # Ensure the file is always created

                 if not dest.exists():

                     dest.write('')

                 shutil.copyfileobj(self.open(), dest)

             return True

         src = self.open()

         copy_content = ''

         while True:

             dest_content = dest.read(32768)

             src_content = src.read(32768)

             copy_content += src_content

             if len(dest_content) == len(src_content) == 0:

                 break

             # If the read content differs between origin and destination,

             # write what was read up to now, and copy the remainder.

             if dest_content != src_content:

                 dest.write(copy_content)

                 shutil.copyfileobj(src, dest)

                 break

         if hasattr(self, 'path') and hasattr(dest, 'path'):

             shutil.copystat(self.path, dest.path)

         return True

     def open(self):

         '''

         Return a file-like object allowing to read() the content of the

         associated file. This is meant to be overloaded in subclasses to return

         a custom file-like object.

         '''

         assert self.path is not None

         return open(self.path, 'rb')

     @property

     def mode(self):

         '''

         Return the file's unix mode, or None if it has no meaning.

         '''

         return None

 class File(BaseFile):

     '''

     File class for plain files.

     '''

     def __init__(self, path):

         self.path = path

     @property

     def mode(self):

         '''

         Return the file's unix mode, as returned by os.stat().st_mode.

         '''

         if platform.system() == 'Windows':

             return None

         assert self.path is not None

         return os.stat(self.path).st_mode

 class ExecutableFile(File):

     '''

     File class for executable and library files on OS/2, OS/X and ELF systems.

     (see mozpack.executables.is_executable documentation).

     '''

     def copy(self, dest, skip_if_older=True):

         real_dest = dest

         if not isinstance(dest, basestring):

             fd, dest = mkstemp()

             os.close(fd)

             os.remove(dest)

         assert isinstance(dest, basestring)

         # If File.copy didn't actually copy because dest is newer, check the

         # file sizes. If dest is smaller, it means it is already stripped and

         # elfhacked, so we can skip.

         if not File.copy(self, dest, skip_if_older) and \

                 os.path.getsize(self.path) > os.path.getsize(dest):

             return False

         try:

             if may_strip(dest):

                 strip(dest)

             if may_elfhack(dest):

                 elfhack(dest)

         except ErrorMessage:

             os.remove(dest)

             raise

         if real_dest != dest:

             f = File(dest)

             ret = f.copy(real_dest, skip_if_older)

             os.remove(dest)

             return ret

         return True

 class AbsoluteSymlinkFile(File):

     '''File class that is copied by symlinking (if available).

     This class only works if the target path is absolute.

     '''

     def __init__(self, path):

         if not os.path.isabs(path):

             raise ValueError('Symlink target not absolute: %s' % path)

         File.__init__(self, path)

     def copy(self, dest, skip_if_older=True):

         assert isinstance(dest, basestring)

         # The logic in this function is complicated by the fact that symlinks

         # aren't universally supported. So, where symlinks aren't supported, we

         # fall back to file copying. Keep in mind that symlink support is

         # per-filesystem, not per-OS.

         # Handle the simple case where symlinks are definitely not supported by

         # falling back to file copy.

         if not hasattr(os, 'symlink'):

             return File.copy(self, dest, skip_if_older=skip_if_older)

         # Always verify the symlink target path exists.

         if not os.path.exists(self.path):

             raise ErrorMessage('Symlink target path does not exist: %s' % self.path)

         st = None

         try:

             st = os.lstat(dest)

         except OSError as ose:

             if ose.errno != errno.ENOENT:

                 raise

         # If the dest is a symlink pointing to us, we have nothing to do.

         # If it's the wrong symlink, the filesystem must support symlinks,

         # so we replace with a proper symlink.

         if st and stat.S_ISLNK(st.st_mode):

             link = os.readlink(dest)

             if link == self.path:

                 return False

             os.remove(dest)

             os.symlink(self.path, dest)

             return True

         # If the destination doesn't exist, we try to create a symlink. If that

         # fails, we fall back to copy code.

         if not st:

             try:

                 os.symlink(self.path, dest)

                 return True

             except OSError:

                 return File.copy(self, dest, skip_if_older=skip_if_older)

         # Now the complicated part. If the destination exists, we could be

         # replacing a file with a symlink. Or, the filesystem may not support

         # symlinks. We want to minimize I/O overhead for performance reasons,

         # so we keep the existing destination file around as long as possible.

         # A lot of the system calls would be eliminated if we cached whether

         # symlinks are supported. However, even if we performed a single

         # up-front test of whether the root of the destination directory

         # supports symlinks, there's no guarantee that all operations for that

         # dest (or source) would be on the same filesystem and would support

         # symlinks.

         #

         # Our strategy is to attempt to create a new symlink with a random

         # name. If that fails, we fall back to copy mode. If that works, we

         # remove the old destination and move the newly-created symlink into

         # its place.

         temp_dest = os.path.join(os.path.dirname(dest), str(uuid.uuid4()))

         try:

             os.symlink(self.path, temp_dest)

         # TODO Figure out exactly how symlink creation fails and only trap

         # that.

         except EnvironmentError:

             return File.copy(self, dest, skip_if_older=skip_if_older)

         # If removing the original file fails, don't forget to clean up the

         # temporary symlink.

         try:

             os.remove(dest)

         except EnvironmentError:

             os.remove(temp_dest)

             raise

         os.rename(temp_dest, dest)

         return True

 class ExistingFile(BaseFile):

     '''

     File class that represents a file that may exist but whose content comes

     from elsewhere.

     This purpose of this class is to account for files that are installed via

     external means. It is typically only used in manifests or in registries to

     account for files.

     When asked to copy, this class does nothing because nothing is known about

     the source file/data.

     Instances of this class come in two flavors: required and optional. If an

     existing file is required, it must exist during copy() or an error is

     raised.

     '''

     def __init__(self, required):

         self.required = required

     def copy(self, dest, skip_if_older=True):

         if isinstance(dest, basestring):

             dest = Dest(dest)

         else:

             assert isinstance(dest, Dest)

         if not self.required:

             return

         if not dest.exists():

             errors.fatal("Required existing file doesn't exist: %s" %

                 dest.path)

 class PreprocessedFile(BaseFile):

     '''

     File class for a file that is preprocessed. PreprocessedFile.copy() runs

     the preprocessor on the file to create the output.

     '''

     def __init__(self, path, depfile_path, marker, defines, extra_depends=None):

         self.path = path

         self.depfile = depfile_path

         self.marker = marker

         self.defines = defines

         self.extra_depends = list(extra_depends or [])

     def copy(self, dest, skip_if_older=True):

         '''

         Invokes the preprocessor to create the destination file.

         '''

         if isinstance(dest, basestring):

             dest = Dest(dest)

         else:

             assert isinstance(dest, Dest)

         # We have to account for the case where the destination exists and is a

         # symlink to something. Since we know the preprocessor is certainly not

         # going to create a symlink, we can just remove the existing one. If the

         # destination is not a symlink, we leave it alone, since we're going to

         # overwrite its contents anyway.

         # If symlinks aren't supported at all, we can skip this step.

         if hasattr(os, 'symlink'):

             if os.path.islink(dest.path):

                 os.remove(dest.path)

         pp_deps = set(self.extra_depends)

         # If a dependency file was specified, and it exists, add any

         # dependencies from that file to our list.

         if self.depfile and os.path.exists(self.depfile):

             target = mozpack.path.normpath(dest.name)

             with open(self.depfile, 'rb') as fileobj:

                 for rule in makeutil.read_dep_makefile(fileobj):

                     if target in rule.targets():

                         pp_deps.update(rule.dependencies())

         skip = False

         if dest.exists() and skip_if_older:

             # If a dependency file was specified, and it doesn't exist,

             # assume that the preprocessor needs to be rerun. That will

             # regenerate the dependency file.

             if self.depfile and not os.path.exists(self.depfile):

                 skip = False

             else:

                 skip = not BaseFile.any_newer(dest.path, pp_deps)

         if skip:

             return False

         deps_out = None

         if self.depfile:

             deps_out = FileAvoidWrite(self.depfile)

         pp = Preprocessor(defines=self.defines, marker=self.marker)

         with open(self.path, 'rU') as input:

             pp.processFile(input=input, output=dest, depfile=deps_out)

         dest.close()

         if self.depfile:

             deps_out.close()

         return True

 class GeneratedFile(BaseFile):

     '''

     File class for content with no previous existence on the filesystem.

     '''

     def __init__(self, content):

         self.content = content

     def open(self):

         return BytesIO(self.content)

 class DeflatedFile(BaseFile):

     '''

     File class for members of a jar archive. DeflatedFile.copy() effectively

     extracts the file from the jar archive.

     '''

     def __init__(self, file):

         from mozpack.mozjar import JarFileReader

         assert isinstance(file, JarFileReader)

         self.file = file

     def open(self):

         self.file.seek(0)

         return self.file

 class XPTFile(GeneratedFile):

     '''

     File class for a linked XPT file. It takes several XPT files as input

     (using the add() and remove() member functions), and links them at copy()

     time.

     '''

     def __init__(self):

         self._files = set()

     def add(self, xpt):

         '''

         Add the given XPT file (as a BaseFile instance) to the list of XPTs

         to link.

         '''

         assert isinstance(xpt, BaseFile)

         self._files.add(xpt)

     def remove(self, xpt):

         '''

         Remove the given XPT file (as a BaseFile instance) from the list of

         XPTs to link.

         '''

         assert isinstance(xpt, BaseFile)

         self._files.remove(xpt)

     def copy(self, dest, skip_if_older=True):

         '''

         Link the registered XPTs and place the resulting linked XPT at the

         destination given as a string or a Dest instance. Avoids an expensive

         XPT linking if the interfaces in an existing destination match those of

         the individual XPTs to link.

         skip_if_older is ignored.

         '''

         if isinstance(dest, basestring):

             dest = Dest(dest)

         assert isinstance(dest, Dest)

         from xpt import xpt_link, Typelib, Interface

         all_typelibs = [Typelib.read(f.open()) for f in self._files]

         if dest.exists():

             # Typelib.read() needs to seek(), so use a BytesIO for dest

             # content.

             dest_interfaces = \

                 dict((i.name, i)

                      for i in Typelib.read(BytesIO(dest.read())).interfaces

                      if i.iid != Interface.UNRESOLVED_IID)

             identical = True

             for f in self._files:

                 typelib = Typelib.read(f.open())

                 for i in typelib.interfaces:

                     if i.iid != Interface.UNRESOLVED_IID and \

                             not (i.name in dest_interfaces and

                                  i == dest_interfaces[i.name]):

                         identical = False

                         break

             if identical:

                 return False

         s = BytesIO()

         xpt_link(all_typelibs).write(s)

         dest.write(s.getvalue())

         return True

     def open(self):

         raise RuntimeError("Unsupported")

     def isempty(self):

         '''

         Return whether there are XPT files to link.

         '''

         return len(self._files) == 0

 class ManifestFile(BaseFile):

     '''

     File class for a manifest file. It takes individual manifest entries (using

     the add() and remove() member functions), and adjusts them to be relative

     to the base path for the manifest, given at creation.

     Example:

         There is a manifest entry "content webapprt webapprt/content/" relative

         to "webapprt/chrome". When packaging, the entry will be stored in

         jar:webapprt/omni.ja!/chrome/chrome.manifest, which means the entry

         will have to be relative to "chrome" instead of "webapprt/chrome". This

         doesn't really matter when serializing the entry, since this base path

         is not written out, but it matters when moving the entry at the same

         time, e.g. to jar:webapprt/omni.ja!/chrome.manifest, which we don't do

         currently but could in the future.

     '''

     def __init__(self, base, entries=None):

         self._entries = entries if entries else []

         self._base = base

     def add(self, entry):

         '''

         Add the given entry to the manifest. Entries are rebased at open() time

         instead of add() time so that they can be more easily remove()d.

         '''

         assert isinstance(entry, ManifestEntry)

         self._entries.append(entry)

     def remove(self, entry):

         '''

         Remove the given entry from the manifest.

         '''

         assert isinstance(entry, ManifestEntry)

         self._entries.remove(entry)

     def open(self):

         '''

         Return a file-like object allowing to read() the serialized content of

         the manifest.

         '''

         return BytesIO(''.join('%s\n' % e.rebase(self._base)

                                for e in self._entries))

     def __iter__(self):

         '''

         Iterate over entries in the manifest file.

         '''

         return iter(self._entries)

     def isempty(self):

         '''

         Return whether there are manifest entries to write

         '''

         return len(self._entries) == 0

 class MinifiedProperties(BaseFile):

     '''

     File class for minified properties. This wraps around a BaseFile instance,

     and removes lines starting with a # from its content.

     '''

     def __init__(self, file):

         assert isinstance(file, BaseFile)

         self._file = file

     def open(self):

         '''

         Return a file-like object allowing to read() the minified content of

         the properties file.

         '''

         return BytesIO(''.join(l for l in self._file.open().readlines()

                                if not l.startswith('#')))

 class MinifiedJavaScript(BaseFile):

     '''

     File class for minifying JavaScript files.

     '''

     def __init__(self, file, verify_command=None):

         assert isinstance(file, BaseFile)

         self._file = file

         self._verify_command = verify_command

     def open(self):

         output = BytesIO()

         minify = JavascriptMinify(self._file.open(), output)

         minify.minify()

         output.seek(0)

         if not self._verify_command:

             return output

         input_source = self._file.open().read()

         output_source = output.getvalue()

         with NamedTemporaryFile() as fh1, NamedTemporaryFile() as fh2:

             fh1.write(input_source)

             fh2.write(output_source)

             fh1.flush()

             fh2.flush()

             try:

                 args = list(self._verify_command)

                 args.extend([fh1.name, fh2.name])

                 subprocess.check_output(args, stderr=subprocess.STDOUT)

             except subprocess.CalledProcessError as e:

                 errors.warn('JS minification verification failed for %s:' %

                     (getattr(self._file, 'path', '<unknown>')))

                 # Prefix each line with "Warning:" so mozharness doesn't

                 # think these error messages are real errors.

                 for line in e.output.splitlines():

                     errors.warn(line)

                 return self._file.open()

         return output

 class BaseFinder(object):

     def __init__(self, base, minify=False, minify_js=False,

         minify_js_verify_command=None):

         '''

         Initializes the instance with a reference base directory.

         The optional minify argument specifies whether minification of code

         should occur. minify_js is an additional option to control minification

         of JavaScript. It requires minify to be True.

         minify_js_verify_command can be used to optionally verify the results

         of JavaScript minification. If defined, it is expected to be an iterable

         that will constitute the first arguments to a called process which will

         receive the filenames of the original and minified JavaScript files.

         The invoked process can then verify the results. If minification is

         rejected, the process exits with a non-0 exit code and the original

         JavaScript source is used. An example value for this argument is

         ('/path/to/js', '/path/to/verify/script.js').

         '''

         if minify_js and not minify:

             raise ValueError('minify_js requires minify.')

         self.base = base

         self._minify = minify

         self._minify_js = minify_js

         self._minify_js_verify_command = minify_js_verify_command

     def find(self, pattern):

         '''

         Yield path, BaseFile_instance pairs for all files under the base

         directory and its subdirectories that match the given pattern. See the

         mozpack.path.match documentation for a description of the handled

         patterns.

         '''

         while pattern.startswith('/'):

             pattern = pattern[1:]

         for p, f in self._find(pattern):

             yield p, self._minify_file(p, f)

     def __iter__(self):

         '''

         Iterates over all files under the base directory (excluding files

         starting with a '.' and files at any level under a directory starting

         with a '.').

             for path, file in finder:

                 ...

         '''

         return self.find('')

     def __contains__(self, pattern):

         raise RuntimeError("'in' operator forbidden for %s. Use contains()." %

                            self.__class__.__name__)

     def contains(self, pattern):

         '''

         Return whether some files under the base directory match the given

         pattern. See the mozpack.path.match documentation for a description of

         the handled patterns.

         '''

         return any(self.find(pattern))

     def _minify_file(self, path, file):

         '''

         Return an appropriate MinifiedSomething wrapper for the given BaseFile

         instance (file), according to the file type (determined by the given

         path), if the FileFinder was created with minification enabled.

         Otherwise, just return the given BaseFile instance.

         '''

         if not self._minify or isinstance(file, ExecutableFile):

             return file

         if path.endswith('.properties'):

             return MinifiedProperties(file)

         if self._minify_js and path.endswith(('.js', '.jsm')):

             return MinifiedJavaScript(file, self._minify_js_verify_command)

         return file

 class FileFinder(BaseFinder):

     '''

     Helper to get appropriate BaseFile instances from the file system.

     '''

     def __init__(self, base, find_executables=True, ignore=(), **kargs):

         '''

         Create a FileFinder for files under the given base directory.

         The find_executables argument determines whether the finder needs to

         try to guess whether files are executables. Disabling this guessing

         when not necessary can speed up the finder significantly.

         ``ignore`` accepts an iterable of patterns to ignore. Entries are

         strings that match paths relative to ``base`` using

         ``mozpack.path.match()``. This means if an entry corresponds

         to a directory, all files under that directory will be ignored. If

         an entry corresponds to a file, that particular file will be ignored.

         '''

         BaseFinder.__init__(self, base, **kargs)

         self.find_executables = find_executables

         self.ignore = ignore

     def _find(self, pattern):

         '''

         Actual implementation of FileFinder.find(), dispatching to specialized

         member functions depending on what kind of pattern was given.

         Note all files with a name starting with a '.' are ignored when

         scanning directories, but are not ignored when explicitely requested.

         '''

         if '*' in pattern:

             return self._find_glob('', mozpack.path.split(pattern))

         elif os.path.isdir(os.path.join(self.base, pattern)):

             return self._find_dir(pattern)

         else:

             return self._find_file(pattern)

     def _find_dir(self, path):

         '''

         Actual implementation of FileFinder.find() when the given pattern

         corresponds to an existing directory under the base directory.

         Ignores file names starting with a '.' under the given path. If the

         path itself has leafs starting with a '.', they are not ignored.

         '''

         for p in self.ignore:

             if mozpack.path.match(path, p):

                 return

         # The sorted makes the output idempotent. Otherwise, we are

         # likely dependent on filesystem implementation details, such as

         # inode ordering.

         for p in sorted(os.listdir(os.path.join(self.base, path))):

             if p.startswith('.'):

                 continue

             for p_, f in self._find(mozpack.path.join(path, p)):

                 yield p_, f

     def _find_file(self, path):

         '''

         Actual implementation of FileFinder.find() when the given pattern

         corresponds to an existing file under the base directory.

         '''

         srcpath = os.path.join(self.base, path)

         if not os.path.exists(srcpath):

             return

         for p in self.ignore:

             if mozpack.path.match(path, p):

                 return

         if self.find_executables and is_executable(srcpath):

             yield path, ExecutableFile(srcpath)

         else:

             yield path, File(srcpath)

     def _find_glob(self, base, pattern):

         '''

         Actual implementation of FileFinder.find() when the given pattern

         contains globbing patterns ('*' or '**'). This is meant to be an

         equivalent of:

             for p, f in self:

                 if mozpack.path.match(p, pattern):

                     yield p, f

         but avoids scanning the entire tree.

         '''

         if not pattern:

             for p, f in self._find(base):

                 yield p, f

         elif pattern[0] == '**':

             for p, f in self._find(base):

                 if mozpack.path.match(p, mozpack.path.join(*pattern)):

                     yield p, f

         elif '*' in pattern[0]:

             if not os.path.exists(os.path.join(self.base, base)):

                 return

             for p in self.ignore:

                 if mozpack.path.match(base, p):

                     return

             # See above comment w.r.t. sorted() and idempotent behavior.

             for p in sorted(os.listdir(os.path.join(self.base, base))):

                 if p.startswith('.') and not pattern[0].startswith('.'):

                     continue

                 if mozpack.path.match(p, pattern[0]):

                     for p_, f in self._find_glob(mozpack.path.join(base, p),

                                                  pattern[1:]):

                         yield p_, f

         else:

             for p, f in self._find_glob(mozpack.path.join(base, pattern[0]),

                                         pattern[1:]):

                 yield p, f

 class JarFinder(BaseFinder):

     '''

     Helper to get appropriate DeflatedFile instances from a JarReader.

     '''

     def __init__(self, base, reader, **kargs):

         '''

         Create a JarFinder for files in the given JarReader. The base argument

         is used as an indication of the Jar file location.

         '''

         assert isinstance(reader, JarReader)

         BaseFinder.__init__(self, base, **kargs)

         self._files = OrderedDict((f.filename, f) for f in reader)

     def _find(self, pattern):

         '''

         Actual implementation of JarFinder.find(), dispatching to specialized

         member functions depending on what kind of pattern was given.

         '''

         if '*' in pattern:

             for p in self._files:

                 if mozpack.path.match(p, pattern):

                     yield p, DeflatedFile(self._files[p])

         elif pattern == '':

             for p in self._files:

                 yield p, DeflatedFile(self._files[p])

         elif pattern in self._files:

             yield pattern, DeflatedFile(self._files[pattern])

         else:

             for p in self._files:

                 if mozpack.path.basedir(p, [pattern]) == pattern:

                     yield p, DeflatedFile(self._files[p])