All libraries should implement this."""
raise NotImplementedError()
+ def byid(self, id):
+ """Returns a previously known manga by its string ID, or
+ raises KeyError if no such manga could be found.
+
+ All libraries should implement this."""
+ raise KeyError(id)
+
def __iter__(self):
"""Return an iterator of all known mangas in this library.
class pagetree(object):
"""Base class for objects in the tree of pages and pagelists.
- All pagetree objects should contain an attribute `stack', contains
- a list of pairs. The last pair in the list should be the pagetree
- object which yielded this pagetree object, along with the index
- which yielded it. Every non-last pair should be the same
+ All pagetree objects should contain an attribute `stack',
+ containing a list of pairs. The last pair in the list should be
+ the pagetree object which yielded this pagetree object, along with
+ the index which yielded it. Every non-last pair should be the same
information for the pair following it. The only objects with empty
- `stack' lists should be `manga' objects."""
- pass
+ `stack' lists should be `manga' objects.
+
+ All non-root pagetree objects should also contain an attribute
+ `id', which should be a string that can be passed to the `byid'
+ function of its parent node to recover the node. Such string ID
+ should be more persistent than the node's numeric index in the
+ parent."""
+
+ def idlist(self):
+ """Returns a list of the IDs necessary to resolve this node
+ from the root node."""
+ if len(self.stack) == 0:
+ raise Exception("Cannot get ID list on root node.")
+ return [n.id for n, i in self.stack[1:]] + [self.id]
+
+ def byidlist(self, idlist):
+ if len(idlist) == 0:
+ return self
+ return self.byid(idlist[0]).byidlist(idlist[1:])
class pagelist(pagetree):
"""Class representing a list of either pages, or nested
All pagelists need to implement this."""
raise NotImplementedError()
+ def byid(self, id):
+ """Return the direct sub-node of this pagelist which has the
+ given string ID. If none is found, a KeyError is raised.
+
+ This default method iterates the children of this node, but
+ may be overridden by some more efficient implementation.
+ """
+ for ch in self:
+ if ch.id == id:
+ return ch
+ raise KeyError(id)
+
class manga(pagelist):
"""Class reprenting a single manga. Includes the pagelist class,
- and all constraints valid for it."""
+ and all constraints valid for it.
+
+ A manga is a root pagetree node, but should also contain an `id'
+ attribute, which can be used to recover the manga from its
+ library's `byid' function."""
pass
class page(pagetree):
when exiting the with-scope.
All imgstreams should contain an attribute `ctype', being the
- Content-Type of the image being read by the stream."""
+ Content-Type of the image being read by the stream, and `clen`,
+ being either an int describing the total number of bytes in the
+ stream, or None if the value is not known in advance."""
def __enter__(self):
return self
def __exit__(self, *exc_info):
self.close()
+ def fileno(self):
+ """If reading the imgstream may block, fileno() should return
+ a file descriptor that can be polled. If fileno() returns
+ None, that should mean that reading will not block."""
+ return None
+
def close(self):
"""Close this stream."""
raise NotImplementedError()
class cursor(object):
def __init__(self, ob):
- self.cur = self.descend(ob)
+ if isinstance(ob, cursor):
+ self.cur = ob.cur
+ else:
+ self.cur = self.descend(ob)
def descend(self, ob):
while isinstance(ob, pagelist):