From 139fe97db6e0cdbfb5f2f09477351a13d1e52964 Mon Sep 17 00:00:00 2001
From: scottsanderson <ssanderson@quantopian.com>
Date: Wed, 25 Jul 2012 14:45:04 -0400
Subject: [PATCH] new files for generator components

---
 zipline/gens/mongods.py | 69 +++++++++++++++++++++++++++++++++++++++++
 zipline/gens/scratch.py | 14 +++++++++
 zipline/gens/utils.py   |  5 +++
 3 files changed, 88 insertions(+)
 create mode 100644 zipline/gens/mongods.py
 create mode 100644 zipline/gens/scratch.py
 create mode 100644 zipline/gens/utils.py

diff --git a/zipline/gens/mongods.py b/zipline/gens/mongods.py
new file mode 100644
index 00000000..417a1f70
--- /dev/null
+++ b/zipline/gens/mongods.py
@@ -0,0 +1,69 @@
+"""
+Generator-style DataSource that loads from MongoDB.
+"""
+
+import pytz
+import logbook
+
+from pymongo import ASCENDING
+
+from zipline import ndict
+from zipline.gens.utils import stringify_args
+
+import zipline.protocol as zp
+
+def create_pymongo_iterator(self, collection, filter, start_date, end_date):
+    """
+    See the comments on :py:class:`zipline.messaging.DataSource` for
+    expected content of self.filter. Spec must adhere to that definition.
+    Returns an iterator that spits out raw objects loaded from MongoDB.
+    """
+    log = logbook.Logger("MongoDBQuery")
+
+    # Object that will hold our database query.
+    spec = {}
+
+    # add the filters from the algorithm.
+    for name, value in filter.iteritems():
+
+        # Add the list of sids that we care about.
+        if name == 'sid':
+            assert isinstance(value, sid)
+            sid_range = {'sid':{'$in':value}}
+            spec.update(sid_range)
+            
+    # limit the data to the date range [start, end], inclusive
+    date_range = {'dt':{'$gte':self.start, '$lte':self.end}}
+    spec.update(date_range)
+
+    fields = ['sid','price','volume','dt']
+
+    # In our collection, load all objects matching spec.  Of those
+    # objects, get only the fields matching fields, and return the
+    # loaded objects sorted by dt from least to greatest.
+
+    cursor = self.collection.find(
+        fields   = fields,
+        spec     = spec,
+        sort     = [("dt",ASCENDING)],
+        slave_ok = True
+    )
+
+    # Optimize the cursor sort to query in 'dt' and 'sid' order.
+    cursor = cursor.hint([('dt', ASCENDING),('sid', ASCENDING)])
+
+    # Set up the iterator
+    iterator = iter(self.cursor)
+    log.info("MongoDataSource iterator ready")
+    return iterator
+
+
+def MongoTradeHistoryGen(collection, filter, start_date, end_date):
+    
+    iterator = create_pymongo_iterator(collection, filter, start_date, end_date)
+    source_id = "MongoTradeHistoryGen" + stringify_args(collection, filter, start_date, end_date)
+
+    for event in iterator:
+        
+    
+            
diff --git a/zipline/gens/scratch.py b/zipline/gens/scratch.py
new file mode 100644
index 00000000..931ddec9
--- /dev/null
+++ b/zipline/gens/scratch.py
@@ -0,0 +1,14 @@
+
+class gen_wrapper(object):
+    
+    def __init__(self, val):
+        self.val = val
+        self.iterator = iter(xrange(self.val))
+    def reset_iter(self):
+        self.val
+
+    def __iter__(self):
+        return self.iterator
+
+    def next():
+        return self.iterator.next()
diff --git a/zipline/gens/utils.py b/zipline/gens/utils.py
new file mode 100644
index 00000000..0c2f468d
--- /dev/null
+++ b/zipline/gens/utils.py
@@ -0,0 +1,5 @@
+def stringify_args(*args, **kwargs):
+    """Define a unique string for any set of args."""
+    arg_string = '_'.join([str(arg) for arg in args])
+    kwarg_string = '_'.join([str(key) + '=' + str(value) for key, value in kwargs])
+    combined = ':'.join([arg_string, kwarg_string])