"""CherryPy Library"""

# Deprecated in CherryPy 3.2 -- remove in CherryPy 3.3
from cherrypy.lib.reprconf import unrepr, modules, attributes

class file_generator(object):
    """Yield the given input (a file object) in chunks (default 64k). (Core)"""

    def __init__(self, input, chunkSize=65536):
        self.input = input
        self.chunkSize = chunkSize

    def __iter__(self):
        return self

    def __next__(self):
        chunk = self.input.read(self.chunkSize)
        if chunk:
            return chunk
        else:
            if hasattr(self.input, 'close'):
                self.input.close()
            raise StopIteration()
    next = __next__

def file_generator_limited(fileobj, count, chunk_size=65536):
    """Yield the given file object in chunks, stopping after `count`
    bytes has been emitted.  Default chunk size is 64kB. (Core)
    """
    remaining = count
    while remaining > 0:
        chunk = fileobj.read(min(chunk_size, remaining))
        chunklen = len(chunk)
        if chunklen == 0:
            return
        remaining -= chunklen
        yield chunk

def set_vary_header(response, header_name):
    "Add a Vary header to a response"
    varies = response.headers.get("Vary", "")
    varies = [x.strip() for x in varies.split(",") if x.strip()]
    if header_name not in varies:
        varies.append(header_name)
    response.headers['Vary'] = ", ".join(varies)
