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import errno
import os
import shutil
# The classes in this module implement on-disk storage for Lodju. A Lodju
# "document" consists of an index file, a bunch of untouched, original
# photos, and thumbnails. At some point in the future, there might be
# additional things stored in the document.
#
# The document is implemented on disk as a directory. If the document
# is called "foo.lodju", then the disk structure looks like this:
#
# foo.lodju/
# lodju.xml Index file
# orig/ Original photo files
# 1.jpg Photo with identifier 1
# 2.jpg Photo with identifier 2
# thumb/ Thumbnail files
# 1.jpg Thumbnail for photo with id 1
# 2.jpg Thumbnail for photo with id 2
#
# When the user has "foo.lodju" open, they will make some changes to it:
# import photos, delete photos, change meta data, and so on. These changes
# need to actually happen on disk in the above directory structure only
# after "foo.lodju" is saved; in the mean while, they need to be stored
# in some other way. This way:
#
# foo.lodju/
# orig.new/ New imported files
# thumb.new/ New thumbnails
#
# List of files to be deleted is kept in memory, as is the new set of meta
# data. When it comes time to save, Lodju will write a new lodju.xml,
# delete all files to be deleted from orig and thumb, and copy all new
# files from orig.new to orig, and from thumb.new to thumb.
#
# This scheme does not allow multiple instances of Lodju making simultaneous
# modifications to foo.lodju. I doubt this matters. If this is wanted, the
# whole design of Lodju needs to be re-thought so that changes made in one
# instance are instantly visible in every other instance. This probably
# indicates a server and database.
#
# When a new Storage object is created, it will create the corresponding
# directory on demand. This means that it may be created even before
# the user presses save. However, when the Storage.discard() method is
# called, if the directory didn't exist beforehand, it is deleted.
class Storage:
known_dirs = [u"orig", u"orig.new", u"thumb", u"thumb.new"]
known_files = [u"lodju.xml"]
def __init__(self, filename):
assert type(filename) == type(u"")
if filename == u"":
self.filename = self.make_unnamed_dir()
self.dirs_should_exist = 0
else:
self.filename = filename
self.dirs_should_exist = os.path.exists(self.filename)
self.filename = os.path.abspath(self.filename)
assert type(filename) == type(u"")
self.remove_ids = []
def make_unnamed_dir(self):
try:
os.mkdir(u"unnamed.lodju")
except OSError:
pass
else:
return u"unnamed.lodju"
for i in range(100):
name = u"unnamed-%d.lodju" % i
try:
os.mkdir(name)
except OSError:
pass
else:
return name
raise OSError((errno.EACCES, os.strerror(errno.EACCES)))
def mkdirs(self):
if not os.path.exists(self.filename):
os.makedirs(self.filename)
for subdir in self.known_dirs:
name = os.path.join(self.filename, subdir)
if not os.path.exists(name):
os.makedirs(name)
def rename_new_files(self):
for basename in self.known_files:
fullname = os.path.join(self.filename, basename)
if os.path.isfile(fullname + u".new"):
os.rename(fullname + u".new", fullname)
def move_files_in_dotnew_dirs(self):
for subdir in filter(lambda s: s[-4:] == u".new", self.known_dirs):
fromdir = os.path.join(self.filename, subdir)
todir = os.path.join(self.filename, subdir[:-4])
for basename in os.listdir(fromdir):
os.rename(os.path.join(fromdir, basename),
os.path.join(todir, basename))
def commit_removes(self):
for subdir in self.known_dirs:
subfull = os.path.join(self.filename, subdir)
idfulls = map(lambda s: os.path.join(subfull, s), self.remove_ids)
for name in idfulls:
if os.path.exists(name):
os.remove(name)
self.remove_ids = []
def save(self):
self.mkdirs()
self.commit_removes()
self.rename_new_files()
self.move_files_in_dotnew_dirs()
self.dirs_should_exist = 1
def new_file(self, basename, contents):
assert basename in self.known_files
self.mkdirs()
f = open(os.path.join(self.filename, basename + u".new"), "w")
f.write(contents.encode("utf-8"))
f.close()
def discard(self):
# Unconditionally remove all the unsaved stuff.
for known_file in self.known_files:
name = os.path.join(self.filename, known_file + u".new")
if os.path.isfile(name):
os.remove(name)
for subdir in filter(lambda s: s[-4:] == u".new", self.known_dirs):
dirname = os.path.join(self.filename, subdir)
if os.path.isdir(dirname):
for basename in os.listdir(dirname):
name = os.path.join(dirname, basename)
if os.path.isfile(name):
os.remove(name)
# Remove everything else, too, if there directory shouldn't exist.
if not self.dirs_should_exist and os.path.isdir(self.filename):
for subdir in self.known_dirs:
name = os.path.join(self.filename, subdir)
if os.path.exists(name):
shutil.rmtree(name)
for basename in self.known_files:
fullname = os.path.join(self.filename, basename)
if os.path.isfile(fullname):
os.remove(fullname)
if os.path.isfile(fullname + u".new"):
os.remove(fullname + u".new")
os.rmdir(self.filename)
def new_original(self, id):
self.mkdirs()
f = open(os.path.join(os.path.join(self.filename, u"orig.new"),
id + u".new"),
"w")
return f
def close_original(self, id, file):
file.close()
dirname = os.path.join(self.filename, u"orig.new")
os.rename(os.path.join(dirname, id + u".new"),
os.path.join(dirname, id))
def new_thumbnail(self, id):
self.mkdirs()
f = open(os.path.join(os.path.join(self.filename, u"thumb.new"),
id + u".new"),
"w")
return f
def close_thumbnail(self, id, file):
file.close()
dirname = os.path.join(self.filename, u"thumb.new")
os.rename(os.path.join(dirname, id + u".new"),
os.path.join(dirname, id))
def read_file(self, basename):
try:
f = open(os.path.join(self.filename, basename), "r")
except IOError:
return u""
data = f.read()
f.close()
return data
def get_original_size(self, id):
filename = self.get_filename([u"orig", u"orig.new"], id)
if filename:
try:
ret = os.stat(filename)
except IOError:
return 0
return ret.st_size
else:
return 0
def get_file(self, basename):
data = self.read_file(basename + ".new")
if data == u"":
return self.read_file(basename)
else:
return data
def open_file(self, dirname, basename):
name = os.path.join(os.path.join(self.filename, dirname), basename)
try:
return open(name, "r")
except IOError:
return None
def open_image(self, dirname, id):
f = self.open_file(dirname + u".new", id)
if f == None:
f = self.open_file(dirname, id)
return f
def get_filename(self, subdirs, id):
for subdir in subdirs:
name = os.path.join(os.path.join(self.filename, subdir), id)
if os.path.isfile(name):
return name
return None
def get_original_filename(self, id):
return self.get_filename([u"orig.new", u"orig"], id)
def get_thumbnail_filename(self, id):
return self.get_filename([u"thumb.new", u"thumb"], id)
def new_thumbnail_filename(self, id):
return os.path.join(os.path.join(self.filename, u"thumb.new"),
id + u".new")
def new_thumbnail_commit(self, id):
new_name = self.new_thumbnail_filename(id)
assert new_name[-4:] == u".new"
os.rename(new_name, new_name[:-4])
def get_original(self, id):
return self.open_image(u"orig", id)
def get_thumbnail(self, id):
return self.open_image(u"thumb", id)
def remove(self, id):
self.remove_ids.append(id)
# XXX this needs to be done in a background task
# Imagine the UI freezing while a hundred gigabytes of photos are
# copied
def save_as(self, new_filename):
assert type(new_filename) == type(u"")
st = Storage(new_filename)
for file in self.known_files:
data = self.get_file(file)
if data:
st.new_file(file, data)
for subdir in self.known_dirs:
fromdir = os.path.join(self.filename, subdir)
if subdir[-4:] == u".new":
todir = os.path.join(new_filename, subdir[:-4])
else:
todir = os.path.join(new_filename, subdir)
if os.path.isdir(fromdir):
for basename in os.listdir(fromdir):
fromfile = os.path.join(fromdir, basename)
tofile = os.path.join(todir, basename)
shutil.copyfile(fromfile, tofile)
st.save()
self.filename = st.filename
def rename(self, new_filename):
if os.path.isdir(self.filename):
os.rename(self.filename, new_filename)
self.filename = new_filename
self.dirs_should_exist = 1
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