Remove sqlite3 fallback imports and associated checks.

sqlite3 was add to the stdlib in python2.5

IPython/core/history.py

@@ -8,13 +8,7 b' import atexit'
 import datetime
 import os
 import re
-try:
-    import sqlite3
-except ImportError:
-    try:
-        from pysqlite2 import dbapi2 as sqlite3
-    except ImportError:
-        sqlite3 = None
+import sqlite3
 import threading
 
 from traitlets.config.configurable import LoggingConfigurable
@@ -49,26 +43,8 b' class DummyDB(object):'
         pass
 
 
-@decorator
-def needs_sqlite(f, self, *a, **kw):
-    """Decorator: return an empty list in the absence of sqlite."""
-    if sqlite3 is None or not self.enabled:
-        return []
-    else:
-        return f(self, *a, **kw)
-
-
-if sqlite3 is not None:
-    DatabaseError = sqlite3.DatabaseError
-    OperationalError = sqlite3.OperationalError
-else:
-    @undoc
-    class DatabaseError(Exception):
-        "Dummy exception when sqlite could not be imported. Should never occur."
-    
-    @undoc
-    class OperationalError(Exception):
-        "Dummy exception when sqlite could not be imported. Should never occur."
+DatabaseError = sqlite3.DatabaseError
+OperationalError = sqlite3.OperationalError
 
 # use 16kB as threshold for whether a corrupt history db should be saved
 # that should be at least 100 entries or so
@@ -302,7 +278,6 b' class HistoryAccessor(HistoryAccessorBase):'
             return ((ses, lin, (inp, out)) for ses, lin, inp, out in cur)
         return cur
 
-    @needs_sqlite
     @catch_corrupt_db
     def get_session_info(self, session):
         """Get info about a session.
@@ -558,7 +533,6 b' class HistoryManager(HistoryAccessor):'
         profile_dir = self.shell.profile_dir.location
         return os.path.join(profile_dir, 'history.sqlite')
     
-    @needs_sqlite
     def new_session(self, conn=None):
         """Get a new session number."""
         if conn is None:
@@ -769,7 +743,6 b' class HistoryManager(HistoryAccessor):'
                 conn.execute("INSERT INTO output_history VALUES (?, ?, ?)",
                                 (self.session_number,)+line)
 
-    @needs_sqlite
     def writeout_cache(self, conn=None):
         """Write any entries in the cache to the database."""
         if conn is None:
@@ -818,7 +791,6 b' class HistorySavingThread(threading.Thread):'
         self.enabled = history_manager.enabled
         atexit.register(self.stop)
 
-    @needs_sqlite
     def run(self):
         # We need a separate db connection per thread:
         try: