# (Be in -*- python -*- mode.)
#
# ====================================================================
# Copyright (c) 2000-2008 CollabNet.  All rights reserved.
#
# This software is licensed as described in the file COPYING, which
# you should have received as part of this distribution.  The terms
# are also available at http://subversion.tigris.org/license-1.html.
# If newer versions of this license are posted there, you may use a
# newer version instead, at your option.
#
# This software consists of voluntary contributions made by many
# individuals.  For exact contribution history, see the revision
# history and logs, available at http://cvs2svn.tigris.org/.
# ====================================================================

"""This module contains the SymbolDatabase class."""


from cvs2hg_lib.compat import cPickle

from cvs2hg_lib import config
from cvs2hg_lib.artifact_manager import artifact_manager


class SymbolDatabase:
    """Read-only access to symbol database.

    This class allows iteration and lookups id -> symbol, where symbol
    is a TypedSymbol instance.  The whole database is read into memory
    upon construction."""

    def __init__(self):
        # A map { id : TypedSymbol }
        self._symbols = {}

        f = open(artifact_manager.get_temp_file(config.SYMBOL_DB), 'rb')
        symbols = cPickle.load(f)
        f.close()
        for symbol in symbols:
            self._symbols[symbol.id] = symbol

    def get_symbol(self, id):
        """Return the symbol instance with id ID.

        Raise KeyError if the symbol is not known."""

        return self._symbols[id]

    def __iter__(self):
        """Iterate over the Symbol instances within this database."""

        return self._symbols.itervalues()

    def close(self):
        self._symbols = None


def create_symbol_database(symbols):
    """Create and fill a symbol database.

    Record each symbol that is listed in SYMBOLS, which is an iterable
    containing Trunk and TypedSymbol objects."""

    f = open(artifact_manager.get_temp_file(config.SYMBOL_DB), 'wb')
    cPickle.dump(symbols, f, -1)
    f.close()

