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# Copyright 2004 Daniel Burrows
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# This maps filenames to active file objects. It is responsible for
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# managing file objects that exist during the program's execution (as
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# opposed to the cache).
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# This could be merged with the cache, but then I'd have to write
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# custom picklers to only pickle the cache data, which doesn't work
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# with cPickle, and the only real advantage is that you don't have to
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# maintain the cache data separately from the store. Given that
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# invalid cache info is explicitly allowed (it just has to be
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# recalculated on startup), this is not a huge deal.
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# Circular symlinks will be broken. If a file has multiple names,
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# some of the names will be arbitrarily discarded.
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class FileStoreFileOperationError(Exception):
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"""An error that indicates that an operation failed on some files.
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The recommended (multi-line) error message is stored in the
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strerror attribute."""
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def __init__(self, failed, strerror):
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self.__strerror=strerror
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def __getattr__(self, name):
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if name == 'strerror':
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return '%s (%s)'%(fn,strerror)
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self.strerror='%s%s'%(self.__strerror,'\n'.join(map(make_error, self.failed)))
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raise AttributeError, name
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class SaveError(FileStoreFileOperationError):
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"""An error that indicates that some files failed to be saved."""
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def __init__(self, failed):
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FileStoreFileOperationError.__init__(self, failed, 'Changes to the following files could not be saved:\n')
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# Return a list of the failed files
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return 'Failed to save files: %s'%','.join(map(lambda x:x[0], self.failed))
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class LoadError(FileStoreFileOperationError):
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"""An error that indicates that some files failed to be saved."""
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def __init__(self, failed):
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FileStoreFileOperationError.__init__(self, failed, 'The following files could not be read:\n')
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# Return a list of the failed files
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return 'Failed to load files: %s'%','.join(map(lambda x:x[0], self.failed))
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class NotDirectoryError(Exception):
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"""This error is raised when a non-directory is passed to the add_dir method."""
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def __init__(self, dir):
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Exception.__init__(self, dir)
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self.strerror='%s is not a directory'%dir
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"Returns the extension of the given filename, or None if it has no extension."
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if not '.' in fn or fn.rfind('.')==len(fn)-1:
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return fn[fn.rfind('.')+1:]
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"""A collection of music files, indexed by name. Files are added
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to the store using the add_dir and add_file functions. Each file
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has exactly one corresponding 'file object' in the store, whose
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lifetime is equal to that of the store itself."""
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def __init__(self, cache):
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"""Initializes an empty store attached to the given cache."""
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self.modified_files=sets.Set()
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self.inodes=sets.Set()
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def add_dir(self, dir, callback=lambda cur,max:None, set=None):
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"""Adds the given directory and any files recursively
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contained inside it to this file store. 'set' may be a
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mutable set; file objects added as a result of this operation
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will be placed in 'set'."""
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if not os.path.isdir(dir):
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raise NotDirectoryError(dir)
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self.__find_files(dir, sets.Set(), candidates, callback)
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for fn in candidates:
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self.add_file(fn, set)
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raise LoadError(failed)
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# Finds all files in the given directory and subdirectories,
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# following symlinks and avoiding cycles.
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def __find_files(self, dir, seen_dirs, output, callback=lambda cur,max:None):
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"""Returns a list of all files contained in the given directory and
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subdirectories which have an extension that we recognize. The
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result is built in the list 'output'."""
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assert(os.path.isdir(dir))
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dir_ino=os.stat(dir).st_ino
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if dir_ino not in seen_dirs and os.access(dir, os.R_OK|os.X_OK):
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seen_dirs.add(dir_ino)
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for name in os.listdir(dir):
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fullname=os.path.join(dir, name)
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if os.path.isfile(fullname) and musicfile.file_types.has_key(fname_ext(fullname)):
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output.append(fullname)
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elif os.path.isdir(fullname):
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self.__find_files(fullname, seen_dirs, output, callback)
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def add_file(self, fn, set=None):
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"""Adds the given file to the store. If an exception is
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raised when we try to open the file, print it and
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continue. 'set' may be a mutable set, in which case any file
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object which is successfully created will be added to it."""
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fn=os.path.normpath(fn)
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if self.files.has_key(fn):
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# We've already got one! (it's very nice, too)
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set.add(self.files[fn])
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if file_ino not in self.inodes and os.access(fn, os.R_OK):
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self.inodes.add(file_ino)
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# Find the file extension and associated handler
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if musicfile.file_types.has_key(ext):
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cacheinf=self.cache.get(fn, st)
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new_file=musicfile.file_types[ext](self, fn, cacheinf)
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self.files[fn]=new_file
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self.cache.put(new_file, st)
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except EnvironmentError,e:
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raise LoadError([(fn, e.strerror)])
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except musicfile.MusicFileError,e:
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raise LoadError([(fn, e.strerror)])
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raise LoadError([(fn, None)])
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def commit(self, callback=lambda cur,max:None, S=None):
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"""Commit all changes to files in the set S to the store. If
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S is not specified or None, it defaults to the entire store."""
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modified=self.modified_files
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modified=S & self.modified_files
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except EnvironmentError,e:
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failed.append((f.fn,e.strerror))
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except musicfile.MusicFileError,e:
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failed.append((f.fn,e.strerror))
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failed.append((f.fn,None))
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raise SaveError(failed)
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def revert(self, callback=lambda cur,max:None, S=None):
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"""Revert all modifications to files in the set S. If S is
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not specified or None, it defaults to the entire store."""
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modified=self.modified_files
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modified=S & self.modified_files
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def set_modified(self, file, modified):
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"""Updates whether the given file is known to be modified."""
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self.modified_files.add(file)
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self.modified_files.remove(file)
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def modified_count(self, S=None):
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"""Returns the number of files in the set S that are modified.
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If S is not specified or None, it defaults to the entire
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modified=self.modified_files
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modified=S & self.modified_files
added
removed
build/lib/musiclibrarian/filestore.py
