From 658735f5b4e07f2b0ceb585f9e38e6f5d2f525cc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C3=A9dric=20Krier?= <ced@b2ck.com>
Date: Tue, 7 Jun 2011 11:35:50 +0200
Subject: [PATCH 1/6] Keep user in context when browsing user

It is needed to allow override of user values per user like the change of
company by context.

review30003
---
 trytond/ir/rule.py | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/trytond/ir/rule.py b/trytond/ir/rule.py
index 10e4d662f0..12e61f0846 100644
--- a/trytond/ir/rule.py
+++ b/trytond/ir/rule.py
@@ -163,6 +163,7 @@ class Rule(ModelSQL, ModelView):
         rule_group_user_obj = self.pool.get('ir.rule.group-res.user')
         rule_group_group_obj = self.pool.get('ir.rule.group-res.group')
         user_group_obj = self.pool.get('res.user-res.group')
+        user_obj = self.pool.get('res.user')
 
         cursor = Transaction().cursor
         cursor.execute('SELECT r.id FROM "' + self._table + '" r ' \
@@ -191,15 +192,17 @@ class Rule(ModelSQL, ModelView):
         clause_global = {}
         operand2query = self._operand_get('res.user', level=1,
                 recur=['many2one'], root_tech='user', root='User')
+        user_id = Transaction().user
+        with Transaction().set_user(0, set_context=True):
+            user = user_obj.browse(user_id)
         # Use root user without context to prevent recursion
-        user = Transaction().user
         with contextlib.nested(Transaction().set_user(0),
                 Transaction().set_context(user=0)):
             for rule in self.browse(ids):
                 dom = safe_eval("[('%s', '%s', %s)]" % \
                         (rule.field.name, rule.operator,
                             operand2query[rule.operand]), {
-                                'user': self.pool.get('res.user').browse(user),
+                                'user': user,
                                 'time': time,
                                 })
 
@@ -226,7 +229,8 @@ class Rule(ModelSQL, ModelView):
                         'FROM "' + rule_group_group_obj._table + '" g_rel ' \
                             'JOIN "' + user_group_obj._table + '" u_rel ' \
                                 'ON g_rel.group_id = u_rel.gid ' \
-                        'WHERE u_rel.uid = %s))', (model_name, user, user))
+                        'WHERE u_rel.uid = %s))',
+            (model_name, user_id, user_id))
         fetchone = cursor.fetchone()
         if fetchone:
             group_id = fetchone[0]

From ff5bfb26ba6b21db30de6e181aae705b625ff81e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C3=A9dric=20Krier?= <ced@b2ck.com>
Date: Tue, 7 Jun 2011 11:58:55 +0200
Subject: [PATCH 2/6] Signal is a keyword for MySQL 5.5

issue2037
review30006
---
 trytond/backend/mysql/init.sql | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/trytond/backend/mysql/init.sql b/trytond/backend/mysql/init.sql
index cbb2a56bc4..bb500939fd 100644
--- a/trytond/backend/mysql/init.sql
+++ b/trytond/backend/mysql/init.sql
@@ -121,7 +121,7 @@ CREATE TABLE wkf_transition (
     act_to BIGINT,
     `condition` VARCHAR(255),
     trigger_expr_id VARCHAR(255),
-    signal VARCHAR(255),
+    `signal` VARCHAR(255),
     `group` BIGINT,
     PRIMARY KEY(id),
     CONSTRAINT wkf_transition_act_from_fkey FOREIGN KEY (act_from) REFERENCES wkf_activity (id) ON DELETE CASCADE,

From 0736573c2df00a4b3473b9b1bf9fae68827db82d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nicolas=20=C3=89vrard?= <nicoe@b2ck.com>
Date: Wed, 8 Jun 2011 14:41:36 +0200
Subject: [PATCH 3/6] Add missing colspan attribute for action

---
 trytond/ir/ui/board.rnc | 1 +
 trytond/ir/ui/board.rng | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/trytond/ir/ui/board.rnc b/trytond/ir/ui/board.rnc
index 06662802c0..19fd9c112a 100644
--- a/trytond/ir/ui/board.rnc
+++ b/trytond/ir/ui/board.rnc
@@ -144,5 +144,6 @@ attlist.xpath &=
   attribute position { "inside" | "replace" | "replace_attributes" | "after" | "before" }?
 action = element action { attlist.action, empty }
 attlist.action &= attribute name { text }
+attlist.action &= [ a:defaultValue = "1" ] attribute colspan { text }?
 label |= notAllowed
 start = data | board | label
diff --git a/trytond/ir/ui/board.rng b/trytond/ir/ui/board.rng
index a0c90e3b8d..06d68504d2 100644
--- a/trytond/ir/ui/board.rng
+++ b/trytond/ir/ui/board.rng
@@ -447,6 +447,11 @@
   <define name="attlist.action" combine="interleave">
     <attribute name="name"/>
   </define>
+  <define name="attlist.action" combine="interleave">
+    <optional>
+      <attribute name="colspan" a:defaultValue="1"/>
+    </optional>
+  </define>
   <define name="label" combine="choice">
     <notAllowed/>
   </define>

From 1bb663298b2eafd2070502b77edba69b6030ea77 Mon Sep 17 00:00:00 2001
From: Sharoon Thomas <sharoon.thomas@openlabs.co.in>
Date: Wed, 8 Jun 2011 13:06:22 -0400
Subject: [PATCH 4/6] Change field type of timestamp_rounding to Float to allow
 higher precision timestamp in sequence fixes issue2049

---
 trytond/ir/sequence.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/trytond/ir/sequence.py b/trytond/ir/sequence.py
index aa13ef7d91..828f4b27ce 100644
--- a/trytond/ir/sequence.py
+++ b/trytond/ir/sequence.py
@@ -49,7 +49,7 @@ class Sequence(ModelSQL, ModelView):
             states={
                 'invisible': Not(In(Eval('type'), ['incremental'])),
             }, depends=['type'])
-    timestamp_rounding = fields.Integer('Timestamp Rounding', required=True,
+    timestamp_rounding = fields.Float('Timestamp Rounding', required=True,
             states={
                 'invisible': Not(In(Eval('type'),
                     ['decimal timestamp', 'hexadecimal timestamp'])),

From 641cb994403ec1449b58b67a1c6c2ddbd0c2f672 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C3=A9dric=20Krier?= <ced@b2ck.com>
Date: Tue, 14 Jun 2011 11:28:51 +0200
Subject: [PATCH 5/6] Improve cron

- Fix racing condition with long job
- Add user restriction for issue1817
- Remove unuseful fields:
    - priority (all cron must be runned)
    - running (never visible outside the transaction)
- Rename some field according to their label
- Remove "Work Days" interval type
- Add cron option to activate or not the cron

review38008
---
 bin/trytond         |   3 +
 etc/trytond.conf    |   3 +
 trytond/config.py   |   1 +
 trytond/ir/cron.py  | 218 +++++++++++++++++++++-----------------------
 trytond/ir/cron.xml |  40 ++++----
 trytond/res/ir.xml  |   5 +-
 trytond/server.py   |  24 +++--
 7 files changed, 148 insertions(+), 146 deletions(-)

diff --git a/bin/trytond b/bin/trytond
index ffd5d54750..a55071c781 100755
--- a/bin/trytond
+++ b/bin/trytond
@@ -37,6 +37,8 @@ def parse_commandline():
         help="file where the server pid will be stored")
     parser.add_option("--logfile", dest="logfile",
         help="file where the server log will be stored")
+    parser.add_option("--disable-cron", dest="cron",
+        action="store_false", help="disable cron")
 
     (opt, _) = parser.parse_args()
 
@@ -51,6 +53,7 @@ def parse_commandline():
             'debug_mode',
             'pidfile',
             'logfile',
+            'cron',
             ):
         if getattr(opt, arg) is not None:
             options[arg] = getattr(opt, arg)
diff --git a/etc/trytond.conf b/etc/trytond.conf
index 90e74c0c97..894d201565 100644
--- a/etc/trytond.conf
+++ b/etc/trytond.conf
@@ -90,3 +90,6 @@
 
 # Prevent database listing
 #prevent_dblist = False
+
+# Enable cron
+# cron = True
diff --git a/trytond/config.py b/trytond/config.py
index 6d59bccdcb..ef587c22e5 100644
--- a/trytond/config.py
+++ b/trytond/config.py
@@ -51,6 +51,7 @@ class ConfigManager(object):
             'prevent_dblist': False,
             'init': {},
             'update': {},
+            'cron': True,
         }
         self.configfile = None
 
diff --git a/trytond/ir/cron.py b/trytond/ir/cron.py
index dfa81d2c45..9ed8151779 100644
--- a/trytond/ir/cron.py
+++ b/trytond/ir/cron.py
@@ -6,13 +6,14 @@ import datetime
 from dateutil.relativedelta import relativedelta
 import traceback
 import sys
+import logging
 from trytond.backend import Database
 from trytond.model import ModelView, ModelSQL, fields
 from trytond.tools import safe_eval
 from trytond.transaction import Transaction
+from trytond.backend import TableHandler
 
 _INTERVALTYPES = {
-    'work_days': lambda interval: relativedelta(days=interval),
     'days': lambda interval: relativedelta(days=interval),
     'hours': lambda interval: relativedelta(hours=interval),
     'weeks': lambda interval: relativedelta(weeks=interval),
@@ -26,7 +27,8 @@ class Cron(ModelSQL, ModelView):
     _description = __doc__
     name = fields.Char('Name', required=True, translate=True)
     user = fields.Many2One('res.user', 'Execution User', required=True,
-                           help="The user used to execute this action")
+        domain=[('active', '=', False)],
+        help="The user used to execute this action")
     request_user = fields.Many2One(
         'res.user', 'Request User', required=True,
         help="The user who will receive requests in case of failure")
@@ -35,24 +37,20 @@ class Cron(ModelSQL, ModelView):
     interval_type = fields.Selection( [
        ('minutes', 'Minutes'),
        ('hours', 'Hours'),
-       ('work_days', 'Work Days'),
        ('days', 'Days'),
        ('weeks', 'Weeks'),
        ('months', 'Months'),
        ], 'Interval Unit')
-    numbercall = fields.Integer('Number of calls', select=1,
-       help='Number of times the function is called,\n' \
-               'a negative number indicates that the function ' \
-               'will always be called')
-    doall = fields.Boolean('Repeat missed')
-    nextcall = fields.DateTime('Next call date', required=True,
+    number_calls = fields.Integer('Number of Calls', select=1,
+       help=('Number of times the function is called, a negative '
+           'number indicates that the function will always be '
+           'called'))
+    repeat_missed = fields.Boolean('Repeat Missed')
+    next_call = fields.DateTime('Next Call', required=True,
             select=1)
     model = fields.Char('Model')
     function = fields.Char('Function')
     args = fields.Text('Arguments')
-    priority = fields.Integer('Priority',
-       help='0=Very Urgent\n10=Not urgent')
-    running = fields.Boolean('Running', readonly=True, select=1)
 
     def __init__(self):
         super(Cron, self).__init__()
@@ -62,135 +60,131 @@ class Cron(ModelSQL, ModelView):
                             "properly: \"%s\"\n Traceback: \n\n%s\n"
             })
 
-    def default_nextcall(self):
+    def init(self, module_name):
+        cursor = Transaction().cursor
+
+        # Migration from 2.0: rename numbercall, doall and nextcall
+        table = TableHandler(cursor, self, module_name)
+        table.column_rename('numbercall', 'number_calls')
+        table.column_rename('doall', 'repeat_missed')
+        table.column_rename('nextcall', 'next_call')
+
+        super(Cron, self).init(module_name)
+
+        # Migration from 2.0: work_days removed
+        cursor.execute('UPDATE "%s" '
+            'SET interval_type = %%s '
+            'WHERE interval_type = %%s' % self._table,
+            ('days', 'work_days'))
+
+    def default_next_call(self):
         return datetime.datetime.now()
 
-    def default_priority(self):
-        return 5
-
-    def default_user(self):
-        return int(Transaction().user)
-
     def default_interval_number(self):
         return 1
 
     def default_interval_type(self):
         return 'months'
 
-    def default_numbercall(self):
-        return 1
+    def default_number_calls(self):
+        return -1
 
     def default_active(self):
         return True
 
-    def default_doall(self):
+    def default_repeat_missed(self):
         return True
 
-    def default_running(self):
-        return False
-
     def check_xml_record(self, ids, values):
         return True
 
+    def get_delta(self, cron):
+        '''
+        Return the relativedelta for the next call
+        '''
+        return _INTERVALTYPES[cron.interval_type](cron.interval_number)
+
+    def _get_request_values(self, cron):
+        tb_s = reduce(lambda x, y: x + y,
+                traceback.format_exception(*sys.exc_info()))
+        tb_s = tb_s.decode('utf-8', 'ignore')
+        name = self.raise_user_error('request_title',
+            raise_exception=False)
+        body = self.raise_user_error('request_body', (cron.name, tb_s),
+            raise_exception=False)
+        values = {
+            'name': name,
+            'priority': '2',
+            'act_from': cron.user.id,
+            'act_to': cron.request_user.id,
+            'body': body,
+            'date_sent': datetime.datetime.now(),
+            'references': [
+                ('create', {
+                    'reference': '%s,%s' % (self._name, cron.id),
+                }),
+            ],
+            'state': 'waiting',
+            'trigger_date': datetime.datetime.now(),
+        }
+        return values
+
     def _callback(self, cron):
         try:
-            args = (cron['args'] or []) and safe_eval(cron['args'])
-            obj = self.pool.get(cron['model'])
-            if not obj and hasattr(obj, cron['function']):
-                return False
-            fct = getattr(obj, cron['function'])
-            with Transaction().set_user(cron['user']):
-                fct(*args)
+            args = (cron.args or []) and safe_eval(cron.args)
+            model_obj = self.pool.get(cron.model)
+            with Transaction().set_user(cron.user.id):
+                getattr(model_obj, cron.function)(*args)
         except Exception, error:
             Transaction().cursor.rollback()
 
-            tb_s = ''
-            for line in traceback.format_exception(*sys.exc_info()):
-                try:
-                    line = line.encode('utf-8', 'ignore')
-                except Exception:
-                    continue
-                tb_s += line
-            try:
-                tb_s += str(error).decode('utf-8', 'ignore')
-            except Exception:
-                pass
-
             request_obj = self.pool.get('res.request')
-            try:
-                user_obj = self.pool.get('res.user')
-                req_user = user_obj.browse(cron['request_user'])
-                language = (req_user.language.code if req_user.language
-                        else 'en_US')
-                with contextlib.nested(Transaction().set_user(cron['user']),
-                        Transaction().set_context(language=language)):
-                    rid = request_obj.create({
-                        'name': self.raise_user_error('request_title',
-                            raise_exception=False),
-                         'priority': '2',
-                         'act_from': cron['user'],
-                         'act_to': cron['request_user'],
-                         'body': self.raise_user_error('request_body',
-                             (cron['name'], tb_s), raise_exception=False),
-                         'date_sent': datetime.datetime.now(),
-                         'references': [
-                                ('create', {
-                                    'reference': "ir.cron,%s" % cron['id'],
-                                    }),
-                                ],
-                         'state': 'waiting',
-                         'trigger_date': datetime.datetime.now(),
-                         })
-                Transaction().cursor.commit()
-            except Exception:
-                Transaction().cursor.rollback()
+            req_user = cron.request_user
+            language = (req_user.language.code if req_user.language
+                    else 'en_US')
+            with contextlib.nested(Transaction().set_user(cron.user.id),
+                    Transaction().set_context(language=language)):
+                values = self._get_request_values(cron)
+                rid = request_obj.create(values)
+            Transaction().cursor.commit()
 
-    def pool_jobs(self, db_name):
+    def run(self, db_name):
         now = datetime.datetime.now()
         with Transaction().start(db_name, 0) as transaction:
-            try:
-                transaction.cursor.lock(self._table)
-                transaction.cursor.execute('SELECT * FROM ir_cron '
-                        'WHERE numbercall <> 0 '
-                            'AND active '
-                            'AND nextcall <= %s '
-                            'AND NOT running '
-                            'ORDER BY priority', (datetime.datetime.now(),))
-                crons = transaction.cursor.dictfetchall()
+            transaction.cursor.lock(self._table)
+            cron_ids = self.search([
+                ('number_calls', '!=', 0),
+                ('next_call', '<=', datetime.datetime.now()),
+            ])
+            crons = self.browse(cron_ids)
 
-                for cron in crons:
-                    transaction.cursor.execute('UPDATE ir_cron '
-                        'SET running = %s '
-                        'WHERE id = %s', (True, cron['id']))
-                    nextcall = cron['nextcall']
-                    numbercall = cron['numbercall']
-                    done = False
-
-                    while nextcall < now and numbercall:
-                        if numbercall > 0:
-                            numbercall -= 1
-                        if not done or cron['doall']:
+            for cron in crons:
+                try:
+                    next_call = cron.next_call
+                    number_calls = cron.number_calls
+                    first = True
+                    while next_call < now and number_calls != 0:
+                        if first or cron.repeat_missed:
                             self._callback(cron)
-                        if numbercall:
-                            nextcall += _INTERVALTYPES[cron['interval_type']](
-                                    cron['interval_number'])
-                        done = True
+                        next_call += self.get_delta(cron)
+                        if number_calls > 0:
+                            number_calls -= 1
+                        first = False
 
-                    addsql = ''
-                    addsql_param = []
-                    if not numbercall:
-                        addsql = ', active = %s'
-                        addsql_param = [False]
-                    transaction.cursor.execute("UPDATE ir_cron "
-                        "SET nextcall = %s, "
-                            "running = %s, "
-                            "numbercall = %s" + addsql + " "
-                        "WHERE id = %s",
-                        [nextcall, False, numbercall] + addsql_param +
-                        [cron['id']])
+                    values = {
+                        'next_call': next_call,
+                        'number_calls': number_calls,
+                    }
+                    if not number_calls:
+                        values['active'] = False
+                    self.write(cron.id, values)
                     transaction.cursor.commit()
-            except Exception:
-                transaction.cursor.rollback()
-                raise
+                except Exception:
+                    transaction.cursor.rollback()
+                    tb_s = reduce(lambda x, y: x + y,
+                            traceback.format_exception(*sys.exc_info()))
+                    tb_s = tb_s.decode('utf-8', 'ignore')
+                    logger = logging.getLogger('cron')
+                    logger.error('Exception:\n%s' % tb_s)
 
 Cron()
diff --git a/trytond/ir/cron.xml b/trytond/ir/cron.xml
index ac7842a8e9..cef16614b4 100644
--- a/trytond/ir/cron.xml
+++ b/trytond/ir/cron.xml
@@ -12,16 +12,14 @@ this repository contains the full copyright notices and license terms. -->
             <field name="arch" type="xml">
               <![CDATA[
                 <tree string="Scheduled Actions">
-                    <field name="nextcall"/>
+                    <field name="next_call"/>
                     <field name="name" select="1"/>
                     <field name="user" select="1"/>
                     <field name="request_user" select="2"/>
-                    <field name="priority" select="2"/>
                     <field name="interval_number"/>
                     <field name="interval_type"/>
-                    <field name="numbercall" select="2"/>
+                    <field name="number_calls" select="2"/>
                     <field name="active" select="2"/>
-                    <field name="running" select="2"/>
                 </tree>
                 ]]>
             </field>
@@ -31,37 +29,33 @@ this repository contains the full copyright notices and license terms. -->
             <field name="type">form</field>
             <field name="arch" type="xml">
               <![CDATA[
-                <form string="Scheduled Action" col="6">
+                <form string="Scheduled Action">
                     <label name="name"/>
                     <field name="name"/>
+                    <label name="active"/>
+                    <field name="active"/>
                     <label name="user"/>
                     <field name="user"/>
                     <label name="request_user"/>
                     <field name="request_user"/>
-                    <label name="numbercall"/>
-                    <field name="numbercall"/>
-                    <label name="priority"/>
-                    <field name="priority"/>
-                    <label name="active"/>
-                    <field name="active"/>
                     <label name="interval_number"/>
                     <field name="interval_number"/>
                     <label name="interval_type"/>
                     <field name="interval_type"/>
-                    <label name="nextcall"/>
-                    <field name="nextcall"/>
-                    <label name="doall"/>
-                    <field name="doall"/>
-                    <separator string="Action to trigger" colspan="6"
+                    <label name="number_calls"/>
+                    <field name="number_calls"/>
+                    <label name="next_call"/>
+                    <field name="next_call"/>
+                    <label name="repeat_missed"/>
+                    <field name="repeat_missed"/>
+                    <separator string="Action to trigger" colspan="4"
                         id="action_trigger"/>
                     <label name="model"/>
-                    <field name="model"  readonly="1"/>
+                    <field name="model"/>
                     <label name="function"/>
-                    <field name="function" readonly="1"/>
-                    <label name="running"/>
-                    <field name="running"/>
-                    <separator name="args" colspan="6"/>
-                    <field name="args" colspan="6" readonly="1"/>
+                    <field name="function"/>
+                    <label name="args"/>
+                    <field name="args" colspan="3" widget="char"/>
                 </form>
                 ]]>
             </field>
@@ -69,7 +63,7 @@ this repository contains the full copyright notices and license terms. -->
         <record model="ir.action.act_window" id="act_cron_form">
             <field name="name">Scheduled Actions</field>
             <field name="res_model">ir.cron</field>
-            <field name="context">{'active_test': False}</field>
+            <field name="context"></field>
         </record>
         <record model="ir.action.act_window.view"
             id="act_cron_form_view1">
diff --git a/trytond/res/ir.xml b/trytond/res/ir.xml
index eb98952099..3432f1b693 100644
--- a/trytond/res/ir.xml
+++ b/trytond/res/ir.xml
@@ -663,6 +663,7 @@ this repository contains the full copyright notices and license terms. -->
             <field name="login">user_cron_trigger</field>
             <field name="name">Cron Trigger</field>
             <field name="groups" eval="[('add', ref('group_admin'))]"/>
+            <field name="active" eval="False"/>
         </record>
 
         <record model="ir.cron" id="cron_trigger_time">
@@ -672,8 +673,8 @@ this repository contains the full copyright notices and license terms. -->
             <field name="active" eval="True"/>
             <field name="interval_number">5</field>
             <field name="interval_type">minutes</field>
-            <field name="numbercall">-1</field>
-            <field name="doall" eval="False"/>
+            <field name="number_calls">-1</field>
+            <field name="repeat_missed" eval="False"/>
             <field name="model">ir.trigger</field>
             <field name="function">trigger_time</field>
         </record>
diff --git a/trytond/server.py b/trytond/server.py
index 90405a84ba..d502d05813 100644
--- a/trytond/server.py
+++ b/trytond/server.py
@@ -235,19 +235,25 @@ class TrytonServer(object):
             import psyco
             psyco.full()
 
+        threads = {}
         while True:
             if CONFIG['auto_reload'] and monitor():
                 try:
                     Pool.start()
                 except Exception:
                     pass
-            for dbname in Pool.database_list():
-                pool = Pool(dbname)
-                if 'ir.cron' not in pool.object_name_list():
-                    continue
-                cron_obj = pool.get('ir.cron')
-                thread = threading.Thread(
-                        target=cron_obj.pool_jobs,
-                        args=(dbname,), kwargs={})
-                thread.start()
+            if CONFIG['cron']:
+                for dbname in Pool.database_list():
+                    thread = threads.get(dbname)
+                    if thread and thread.is_alive():
+                        continue
+                    pool = Pool(dbname)
+                    if 'ir.cron' not in pool.object_name_list():
+                        continue
+                    cron_obj = pool.get('ir.cron')
+                    thread = threading.Thread(
+                            target=cron_obj.run,
+                            args=(dbname,), kwargs={})
+                    thread.start()
+                    threads[dbname] = thread
             time.sleep(60)

From 587567077f702e8505fa270a4ab81e6eb7217c83 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C3=A9dric=20Krier?= <ced@b2ck.com>
Date: Tue, 14 Jun 2011 11:44:26 +0200
Subject: [PATCH 6/6] Add LRUDict to use as cache

issue2033
review31005
---
 trytond/backend/database.py   |   8 +-
 trytond/cache.py              |  30 ++++
 trytond/const.py              |   3 +
 trytond/model/browse.py       | 306 ++++++++++++++++++----------------
 trytond/model/modelsql.py     |  11 +-
 trytond/model/modelstorage.py |  11 +-
 trytond/tools/__init__.py     |   4 +
 trytond/tools/ordereddict.py  | 278 ++++++++++++++++++++++++++++++
 8 files changed, 494 insertions(+), 157 deletions(-)
 create mode 100644 trytond/tools/ordereddict.py

diff --git a/trytond/backend/database.py b/trytond/backend/database.py
index 168d1f9624..b61c88baa2 100644
--- a/trytond/backend/database.py
+++ b/trytond/backend/database.py
@@ -1,5 +1,6 @@
 #This file is part of Tryton.  The COPYRIGHT file at the top level of
 #this repository contains the full copyright notices and license terms.
+from trytond.const import CONTEXT_CACHE_SIZE, MODEL_CACHE_SIZE
 
 DatabaseIntegrityError = None
 DatabaseOperationalError = None
@@ -103,7 +104,8 @@ class CursorInterface(object):
     IN_MAX = 1000
 
     def __init__(self):
-        self.cache = {}
+        from trytond.cache import LRUDict
+        self.cache = LRUDict(CONTEXT_CACHE_SIZE)
 
     def get_cache(self, context=None):
         '''
@@ -112,6 +114,7 @@ class CursorInterface(object):
         :param context: the context
         :return: the cache dictionary
         '''
+        from trytond.cache import LRUDict
         if context is None:
             context = {}
         cache_ctx = context.copy()
@@ -119,7 +122,8 @@ class CursorInterface(object):
                 '_delete_records'):
             if i in cache_ctx:
                 del cache_ctx[i]
-        return self.cache.setdefault(repr(cache_ctx), {})
+        return self.cache.setdefault(repr(cache_ctx),
+            LRUDict(MODEL_CACHE_SIZE))
 
     def execute(self, sql, params=None):
         '''
diff --git a/trytond/cache.py b/trytond/cache.py
index dfda7e465c..0dceb911d8 100644
--- a/trytond/cache.py
+++ b/trytond/cache.py
@@ -7,6 +7,7 @@ from threading import Lock
 from trytond.transaction import Transaction
 from trytond.config import CONFIG
 from trytond.backend import Database
+from trytond.tools import OrderedDict
 
 
 class Cache(object):
@@ -167,3 +168,32 @@ class Cache(object):
             cursor.commit()
             cursor.close()
             Cache._resets_lock.release()
+
+
+class LRUDict(OrderedDict):
+    """
+    Dictionary with a size limit.
+    If size limit is reached, it will remove the first added items.
+    """
+    def __init__(self, size_limit, *args, **kwargs):
+        assert size_limit > 0
+        self.size_limit = size_limit
+        super(LRUDict, self).__init__(*args, **kwargs)
+        self._check_size_limit()
+
+    def __setitem__(self, key, value):
+        super(LRUDict, self).__setitem__(key, value)
+        self._check_size_limit()
+
+    def update(*args, **kwargs):
+        super(LRUDict, self).update(*args, **kwargs)
+        self._check_size_limit()
+
+    def setdefault(self, key, default=None):
+        default = super(LRUDict, self).setdefault(key, default=default)
+        self._check_size_limit()
+        return default
+
+    def _check_size_limit(self):
+        while len(self) > self.size_limit:
+            self.popitem(last=False)
diff --git a/trytond/const.py b/trytond/const.py
index 2a569f5f6b..b0a2006442 100644
--- a/trytond/const.py
+++ b/trytond/const.py
@@ -18,4 +18,7 @@ OPERATORS = (
     '>',
 )
 
+CONTEXT_CACHE_SIZE = 10
+MODEL_CACHE_SIZE = 200
+RECORD_CACHE_SIZE = 2000
 BROWSE_FIELD_TRESHOLD = 100
diff --git a/trytond/model/browse.py b/trytond/model/browse.py
index 1d389efc4f..45fea85343 100644
--- a/trytond/model/browse.py
+++ b/trytond/model/browse.py
@@ -2,10 +2,13 @@
 #this repository contains the full copyright notices and license terms.
 from __future__ import with_statement
 import contextlib
-from itertools import islice, ifilter, ifilterfalse
+from itertools import islice, ifilter, ifilterfalse, chain
 from trytond.model import fields
 from trytond.transaction import Transaction
-from trytond.const import BROWSE_FIELD_TRESHOLD
+from trytond.cache import LRUDict
+from trytond.const import MODEL_CACHE_SIZE, RECORD_CACHE_SIZE, \
+        BROWSE_FIELD_TRESHOLD
+
 
 class BrowseRecordList(list):
     '''
@@ -46,164 +49,176 @@ class BrowseRecord(object):
     An object that represents record defined by a ORM object.
     '''
 
-    def __init__(self, record_id, model, local_cache=None):
+    def __init__(self, record_id, model, ids, local_cache):
+        assert isinstance(ids, list)
+        if ids:
+            assert record_id in ids
         self._cursor = Transaction().cursor
         self._user = Transaction().user
-        self._id = record_id
+        self.id = record_id
         self._model = model
         self._model_name = self._model._name
         self._context = Transaction().context
+        self._ids = ids
 
         cache = self._cursor.get_cache(self._context)
-        cache.setdefault(model._name, {})
-        cache.setdefault('_language_cache', {})
+        if model._name not in cache:
+            cache[model._name] = LRUDict(RECORD_CACHE_SIZE)
         self._data = cache[model._name]
-        if not record_id in self._data:
-            self._data[record_id] = {'id': record_id}
         self._cache = cache
-        if local_cache is None:
-            local_cache = {}
-        self._local_cache = local_cache
-        self._local_cache.setdefault(model._name, {})
-        self._local_cache.setdefault('_language_cache', {})
-        self._local_data = self._local_cache[model._name]
-        if not record_id in self._local_data:
-            self._local_data[record_id] = {}
+        assert isinstance(local_cache, LRUDict)
+        self._local_data = local_cache
 
     def __getitem__(self, name):
-        if name == 'id':
-            return self._id
-        if name == 'setLang':
-            return self.setLang
-        if not self._data[self._id].has_key(name) \
-                and not self._local_data[self._id].has_key(name):
-            # build the list of fields we will fetch
+        # Access to LRUDict must be atomic
+        result = self._local_data.get(self.id, {}).get(name)
+        if (self.id in self._local_data
+                and name in self._local_data[self.id]):
+            return result
+        result = self._data.get(self.id, {}).get(name)
+        if self.id in self._data and name in self._data[self.id]:
+            return result
 
-            # fetch the definition of the field which was asked for
-            if name in self._model._columns:
-                col = self._model._columns[name]
-            elif name in self._model._inherit_fields:
-                col = self._model._inherit_fields[name][2]
-            elif hasattr(self._model, name):
-                return getattr(self._model, name)
-            else:
-                raise Exception('Error', 'Programming error: field "%s" ' \
-                        'does not exist in model "%s"!' \
-                        % (name, self._model._name))
+        # build the list of fields we will fetch
+        # fetch the definition of the field which was asked for
+        if name in self._model._columns:
+            col = self._model._columns[name]
+        elif name in self._model._inherit_fields:
+            col = self._model._inherit_fields[name][2]
+        elif hasattr(self._model, name):
+            return getattr(self._model, name)
+        else:
+            raise Exception('Error', 'Programming error: field "%s" ' \
+                    'does not exist in model "%s"!' \
+                    % (name, self._model._name))
 
-            ffields = {}
-            if col.loading == 'eager':
-                field_access_obj = self._model.pool.get('ir.model.field.access')
-                fread_accesses = {}
-                for inherit_name in self._model._inherits:
-                    inherit_obj = self._model.pool.get(inherit_name)
-                    fread_accesses.update(field_access_obj.check(inherit_name,
-                        inherit_obj._columns.keys(), 'read', access=True))
-                fread_accesses.update(field_access_obj.check(self._model._name,
-                    self._model._columns.keys(), 'read', access=True))
-                to_remove = set(x for x, y in fread_accesses.iteritems()
-                        if not y and x != name)
+        ffields = {}
+        if col.loading == 'eager':
+            field_access_obj = self._model.pool.get('ir.model.field.access')
+            fread_accesses = {}
+            for inherit_name in self._model._inherits:
+                inherit_obj = self._model.pool.get(inherit_name)
+                fread_accesses.update(field_access_obj.check(inherit_name,
+                    inherit_obj._columns.keys(), 'read', access=True))
+            fread_accesses.update(field_access_obj.check(self._model._name,
+                self._model._columns.keys(), 'read', access=True))
+            to_remove = set(x for x, y in fread_accesses.iteritems()
+                    if not y and x != name)
 
-                threshold = BROWSE_FIELD_TRESHOLD
-                inherit_threshold = threshold - len(self._model._columns)
+            threshold = BROWSE_FIELD_TRESHOLD
+            inherit_threshold = threshold - len(self._model._columns)
 
-                def not_cached(item):
-                    fname, field = item
-                    return (fname not in self._data[self._id]
-                        and fname not in self._local_data[self._id])
-                def to_load(item):
-                    fname, field = item
-                    return (field.loading == 'eager'
-                        and fname not in to_remove)
-                def overrided(item):
-                    fname, field = item
-                    return fname in self._model._columns
+            def not_cached(item):
+                fname, field = item
+                return (fname not in self._data.get(self.id, {})
+                    and fname not in self._local_data.get(self.id, {}))
+            def to_load(item):
+                fname, field = item
+                return (field.loading == 'eager'
+                    and fname not in to_remove)
+            def overrided(item):
+                fname, field = item
+                return fname in self._model._columns
 
-                if inherit_threshold > 0:
-                    ifields = ((fname, field)
-                        for fname, (_, _, field) in
-                        self._model._inherit_fields.iteritems())
-                    ifields = ifilterfalse(overrided,
-                        ifilter(to_load,
-                            ifilter(not_cached, ifields)))
-                    ifields = islice(ifields, 0, inherit_threshold)
-                    ffields.update(ifields)
-                    threshold -= inherit_threshold
-
-                ifields = ifilter(to_load,
-                    ifilter(not_cached,
-                        self._model._columns.iteritems()))
-                ifields = islice(ifields, 0, threshold)
+            if inherit_threshold > 0:
+                ifields = ((fname, field)
+                    for fname, (_, _, field) in
+                    self._model._inherit_fields.iteritems())
+                ifields = ifilterfalse(overrided,
+                    ifilter(to_load,
+                        ifilter(not_cached, ifields)))
+                ifields = islice(ifields, 0, inherit_threshold)
                 ffields.update(ifields)
+                threshold -= inherit_threshold
 
-            ffields[name] = col
+            ifields = ifilter(to_load,
+                ifilter(not_cached,
+                    self._model._columns.iteritems()))
+            ifields = islice(ifields, 0, threshold)
+            ffields.update(ifields)
 
-            # add datetime_field
-            for field in ffields:
-                if hasattr(field, 'datetime_field') and field.datetime_field:
-                    if field.datetime_field in self._model._columns:
-                        date_field = self._model._columns[field.datetime_field]
-                    else:
-                        date_field = self._model._inherit_fields[
-                                field.datetime_field][2]
-                    ffields[field.datetime_field] = datetime_field
+        ffields[name] = col
 
-            if len(self._data) <= self._cursor.IN_MAX:
-                iterids = self._data.iterkeys()
-            else:
-                iterids = self._local_data.iterkeys()
-            ids = [x for x in iterids \
-                    if not self._data.setdefault(x, {}).has_key(name) \
-                    and not self._local_data.setdefault(x, {}).has_key(name)]
-            # read the data
-            with contextlib.nested(Transaction().set_cursor(self._cursor),
-                    Transaction().set_user(self._user),
-                    Transaction().set_context(self._context)):
-                datas = self._model.read(ids, ffields.keys())
+        # add datetime_field
+        for field in ffields:
+            if hasattr(field, 'datetime_field') and field.datetime_field:
+                if field.datetime_field in self._model._columns:
+                    date_field = self._model._columns[field.datetime_field]
+                else:
+                    date_field = self._model._inherit_fields[
+                            field.datetime_field][2]
+                ffields[field.datetime_field] = datetime_field
 
-                # create browse records for 'remote' models
-                for data in datas:
-                    for i, j in ffields.iteritems():
-                        model = None
-                        if (hasattr(j, 'model_name') and
-                                j.model_name in
-                                self._model.pool.object_name_list()):
-                            model = self._model.pool.get(j.model_name)
-                        elif hasattr(j, 'get_target'):
-                            model = j.get_target(self._model.pool)
-                        if model and j._type in ('many2one', 'one2one'):
-                            if (not data[i]
-                                    and not (isinstance(data[i], (int, long))
-                                        and not isinstance(data[i],
-                                            type(False)))):
-                                data[i] = BrowseRecordNull()
-                            else:
-                                _datetime = None
-                                if (hasattr(j, 'datetime_field')
-                                        and j.datetime_field):
-                                    _datetime = data[j.datetime_field]
-                                with Transaction().set_context(
-                                        _datetime=_datetime):
-                                    data[i] = BrowseRecord(data[i], model,
-                                            local_cache=self._local_cache)
-                        elif (model
-                                and j._type in ('one2many', 'many2many')
-                                and len(data[i])):
+        def filter_(id_):
+            return True
+            if (id_ in self._local_data
+                    and name in self._local_data[id_]):
+                return False
+            if id_ in self._data and name in self._data[id_]:
+                return False
+            return True
+        index = self._ids.index(self.id)
+        ids = list(islice(ifilter(filter_, chain(self._ids, self._ids)),
+            index, self._cursor.IN_MAX + index))
+        model2ids = {}
+        model2cache = {}
+        # read the data
+        with contextlib.nested(Transaction().set_cursor(self._cursor),
+                Transaction().set_user(self._user),
+                Transaction().set_context(self._context)):
+            # create browse records for 'remote' models
+            for data in self._model.read(ids, ffields.keys()):
+                for i, j in ffields.iteritems():
+                    model = None
+                    if (hasattr(j, 'model_name') and
+                            j.model_name in
+                            self._model.pool.object_name_list()):
+                        model = self._model.pool.get(j.model_name)
+                    elif hasattr(j, 'get_target'):
+                        model = j.get_target(self._model.pool)
+                    if model and j._type in ('many2one', 'one2one'):
+                        if (not data[i]
+                                and not (isinstance(data[i], (int, long))
+                                    and not isinstance(data[i],
+                                        type(False)))):
+                            data[i] = BrowseRecordNull()
+                        else:
                             _datetime = None
-                            if hasattr(j, 'datetime_field') and j.datetime_field:
+                            if (hasattr(j, 'datetime_field')
+                                    and j.datetime_field):
                                 _datetime = data[j.datetime_field]
                             with Transaction().set_context(
                                     _datetime=_datetime):
-                                data[i] = BrowseRecordList(BrowseRecord(
-                                    x, model, local_cache=self._local_cache)
-                                    for x in data[i])
-                        if isinstance(j, fields.Function):
-                            self._local_data.setdefault(data['id'], {})[i] = data[i]
-                            del data[i]
-                    self._data[data['id']].update(data)
-        if name in self._local_data[self._id]:
-            return self._local_data[self._id][name]
-        return self._data[self._id][name]
+                                ids = model2ids.setdefault(model, [])
+                                ids.append(data[i])
+                                local_cache = model2cache.setdefault(model,
+                                    LRUDict(RECORD_CACHE_SIZE))
+                                data[i] = BrowseRecord(data[i], model,
+                                    ids, local_cache)
+                    elif (model
+                            and j._type in ('one2many', 'many2many')
+                            and len(data[i])):
+                        _datetime = None
+                        if hasattr(j, 'datetime_field') and j.datetime_field:
+                            _datetime = data[j.datetime_field]
+                        with Transaction().set_context(
+                                _datetime=_datetime):
+                            ids = model2ids.setdefault(model, [])
+                            ids.extend(data[i])
+                            local_cache = model2cache.setdefault(model,
+                                LRUDict(RECORD_CACHE_SIZE))
+                            data[i] = BrowseRecordList(
+                                BrowseRecord(x, model, ids, local_cache)
+                                for x in data[i])
+                    if isinstance(j, fields.Function):
+                        if data['id'] == self.id and i == name:
+                            result = data[i]
+                        self._local_data.setdefault(data['id'], {})[i] = data[i]
+                        del data[i]
+                self._data.setdefault(data['id'], {}).update(data)
+                if data['id'] == self.id and name in data:
+                    result = data[name]
+        return result
 
     def __getattr__(self, name):
         # TODO raise an AttributeError exception
@@ -218,16 +233,16 @@ class BrowseRecord(object):
         return name in self
 
     def __int__(self):
-        return self._id
+        return self.id
 
     def __str__(self):
-        return "BrowseRecord(%s, %d)" % (self._model_name, self._id)
+        return "BrowseRecord(%s, %d)" % (self._model_name, self.id)
 
     def __eq__(self, other):
-        return (self._model_name, self._id) == (other._model_name, other._id)
+        return (self._model_name, self.id) == (other._model_name, other.id)
 
     def __ne__(self, other):
-        return (self._model_name, self._id) != (other._model_name, other._id)
+        return (self._model_name, self.id) != (other._model_name, other.id)
 
     # we need to define __unicode__ even though we've already defined __str__
     # because we have overridden __getattr__
@@ -235,7 +250,7 @@ class BrowseRecord(object):
         return unicode(str(self))
 
     def __hash__(self):
-        return hash((self._model_name, self._id))
+        return hash((self._model_name, self.id))
 
     def __nonzero__(self):
         return True
@@ -246,22 +261,23 @@ class BrowseRecord(object):
         self._context = self._context.copy()
         prev_lang = self._context.get('language') or 'en_US'
         self._context['language'] = lang
-        for cache in (self._cache, self._local_cache):
-            language_cache = cache['_language_cache']
+        for cache in (self._cache, self._local_data):
+            language_cache = cache.setdefault('_language_cache', {})
             for model in cache:
                 if model == '_language_cache':
                     continue
                 for record_id in cache[model]:
                     language_cache.setdefault(prev_lang,
-                            {}).setdefault(model, {})[record_id] = \
-                                    cache[model][record_id]
+                        LRUDict(MODEL_CACHE_SIZE)).setdefault(model,
+                            LRUDict(RECORD_CACHE_SIZE))[record_id] = \
+                            cache[model][record_id]
                     if lang in language_cache \
                             and model in language_cache[lang] \
                             and record_id in language_cache[lang][model]:
                         cache[model][record_id] = \
                                 language_cache[lang][model][record_id]
                     else:
-                        cache[model][record_id] = {'id': record_id}
+                        cache[model][record_id] = {}
 
     def get_eval(self, name):
         res = self[name]
diff --git a/trytond/model/modelsql.py b/trytond/model/modelsql.py
index 7c0d204fec..4d169a1131 100644
--- a/trytond/model/modelsql.py
+++ b/trytond/model/modelsql.py
@@ -5,13 +5,15 @@ import contextlib
 import datetime
 import re
 from decimal import Decimal
+from itertools import islice
 from trytond.model import ModelStorage
 from trytond.model import fields
 from trytond.backend import FIELDS, TableHandler
 from trytond.backend import DatabaseIntegrityError, Database
 from trytond.tools import reduce_ids
-from trytond.const import OPERATORS
+from trytond.const import OPERATORS, RECORD_CACHE_SIZE
 from trytond.transaction import Transaction
+from trytond.cache import LRUDict
 _RE_UNIQUE = re.compile('UNIQUE\s*\((.*)\)', re.I)
 _RE_CHECK = re.compile('CHECK\s*\((.*)\)', re.I)
 
@@ -1196,11 +1198,11 @@ class ModelSQL(ModelStorage):
 
         datas = cursor.dictfetchmany(cursor.IN_MAX)
         cache = cursor.get_cache()
-        cache.setdefault(self._name, {})
+        cache.setdefault(self._name, LRUDict(RECORD_CACHE_SIZE))
         delete_records = Transaction().delete_records.setdefault(self._name,
                 set())
         keys = None
-        for data in datas:
+        for data in islice(datas, 0, cache.size_limit):
             if data['id'] in delete_records:
                 continue
             if not keys:
@@ -1215,8 +1217,7 @@ class ModelSQL(ModelStorage):
                         continue
             for k in keys:
                 del data[k]
-            cache[self._name].setdefault(data['id'], {})
-            cache[self._name][data['id']].update(data)
+            cache[self._name].setdefault(data['id'], {}).update(data)
 
         if len(datas) >= cursor.IN_MAX:
             select_fields2 = [select_fields[0]]
diff --git a/trytond/model/modelstorage.py b/trytond/model/modelstorage.py
index b21b40df1d..5f131c93da 100644
--- a/trytond/model/modelstorage.py
+++ b/trytond/model/modelstorage.py
@@ -19,8 +19,9 @@ from trytond.model.browse import BrowseRecordList, BrowseRecord, \
 from trytond.model.browse import EvalEnvironment
 from trytond.tools import safe_eval, reduce_domain
 from trytond.pyson import PYSONEncoder, PYSONDecoder, PYSON
-from trytond.const import OPERATORS
+from trytond.const import OPERATORS, RECORD_CACHE_SIZE
 from trytond.transaction import Transaction
+from trytond.cache import LRUDict
 
 
 class ModelStorage(Model):
@@ -189,7 +190,7 @@ class ModelStorage(Model):
         trigger_ids = eligibles.keys()
         if not trigger_ids:
             return
-        records = self.browse(chain(*eligibles.values()))
+        records = self.browse(list(chain(*eligibles.values())))
         id2record = dict((x.id, x) for x in records)
         triggers = trigger_obj.browse(trigger_ids)
         for trigger in triggers:
@@ -511,10 +512,10 @@ class ModelStorage(Model):
         :param ids: a list of ids or an id
         :return: a BrowseRecordList or a BrowseRecord
         '''
+        local_cache = LRUDict(RECORD_CACHE_SIZE)
         if isinstance(ids, (int, long)):
-            return BrowseRecord(ids, self)
-        local_cache = {}
-        return BrowseRecordList((BrowseRecord(x, self, local_cache=local_cache)
+            return BrowseRecord(ids, self, [ids], local_cache)
+        return BrowseRecordList((BrowseRecord(x, self, ids, local_cache)
             for x in ids))
 
     def __export_row(self, record, fields_names):
diff --git a/trytond/tools/__init__.py b/trytond/tools/__init__.py
index 21c264dc2e..5a927c7214 100644
--- a/trytond/tools/__init__.py
+++ b/trytond/tools/__init__.py
@@ -2,3 +2,7 @@
 #this repository contains the full copyright notices and license terms.
 from misc import *
 from datetime_strftime import *
+try:
+    from collections import OrderedDict
+except ImportError:
+    from ordereddict import OrderedDict
diff --git a/trytond/tools/ordereddict.py b/trytond/tools/ordereddict.py
new file mode 100644
index 0000000000..d993489a72
--- /dev/null
+++ b/trytond/tools/ordereddict.py
@@ -0,0 +1,278 @@
+# Copyright (C) 2009 by Raymond Hettinger
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+#
+# Backport of OrderedDict() class that runs on Python 2.4, 2.5, 2.6, 2.7 and pypy.
+# Passes Python2.7's test suite and incorporates all the latest updates.
+
+try:
+    from thread import get_ident as _get_ident
+except ImportError:
+    from dummy_thread import get_ident as _get_ident
+
+try:
+    from _abcoll import KeysView, ValuesView, ItemsView
+except ImportError:
+    pass
+
+
+class OrderedDict(dict):
+    'Dictionary that remembers insertion order'
+    # An inherited dict maps keys to values.
+    # The inherited dict provides __getitem__, __len__, __contains__, and get.
+    # The remaining methods are order-aware.
+    # Big-O running times for all methods are the same as for regular dictionaries.
+
+    # The internal self.__map dictionary maps keys to links in a doubly linked list.
+    # The circular doubly linked list starts and ends with a sentinel element.
+    # The sentinel element never gets deleted (this simplifies the algorithm).
+    # Each link is stored as a list of length three:  [PREV, NEXT, KEY].
+
+    def __init__(self, *args, **kwds):
+        '''Initialize an ordered dictionary.  Signature is the same as for
+        regular dictionaries, but keyword arguments are not recommended
+        because their insertion order is arbitrary.
+
+        '''
+        if len(args) > 1:
+            raise TypeError('expected at most 1 arguments, got %d' % len(args))
+        try:
+            self.__root
+        except AttributeError:
+            self.__root = root = []                     # sentinel node
+            root[:] = [root, root, None]
+            self.__map = {}
+        self.__update(*args, **kwds)
+
+    def __setitem__(self, key, value, dict_setitem=dict.__setitem__):
+        'od.__setitem__(i, y) <==> od[i]=y'
+        # Setting a new item creates a new link which goes at the end of the linked
+        # list, and the inherited dictionary is updated with the new key/value pair.
+        if key not in self:
+            root = self.__root
+            last = root[0]
+            last[1] = root[0] = self.__map[key] = [last, root, key]
+        dict_setitem(self, key, value)
+
+    def __delitem__(self, key, dict_delitem=dict.__delitem__):
+        'od.__delitem__(y) <==> del od[y]'
+        # Deleting an existing item uses self.__map to find the link which is
+        # then removed by updating the links in the predecessor and successor nodes.
+        dict_delitem(self, key)
+        link_prev, link_next, key = self.__map.pop(key)
+        link_prev[1] = link_next
+        link_next[0] = link_prev
+
+    def __iter__(self):
+        'od.__iter__() <==> iter(od)'
+        root = self.__root
+        curr = root[1]
+        while curr is not root:
+            yield curr[2]
+            curr = curr[1]
+
+    def __reversed__(self):
+        'od.__reversed__() <==> reversed(od)'
+        root = self.__root
+        curr = root[0]
+        while curr is not root:
+            yield curr[2]
+            curr = curr[0]
+
+    def clear(self):
+        'od.clear() -> None.  Remove all items from od.'
+        try:
+            for node in self.__map.itervalues():
+                del node[:]
+            root = self.__root
+            root[:] = [root, root, None]
+            self.__map.clear()
+        except AttributeError:
+            pass
+        dict.clear(self)
+
+    def popitem(self, last=True):
+        '''od.popitem() -> (k, v), return and remove a (key, value) pair.
+        Pairs are returned in LIFO order if last is true or FIFO order if false.
+
+        '''
+        if not self:
+            raise KeyError('dictionary is empty')
+        root = self.__root
+        if last:
+            link = root[0]
+            link_prev = link[0]
+            link_prev[1] = root
+            root[0] = link_prev
+        else:
+            link = root[1]
+            link_next = link[1]
+            root[1] = link_next
+            link_next[0] = root
+        key = link[2]
+        del self.__map[key]
+        value = dict.pop(self, key)
+        return key, value
+
+    # -- the following methods do not depend on the internal structure --
+
+    def keys(self):
+        'od.keys() -> list of keys in od'
+        return list(self)
+
+    def values(self):
+        'od.values() -> list of values in od'
+        return [self[key] for key in self]
+
+    def items(self):
+        'od.items() -> list of (key, value) pairs in od'
+        return [(key, self[key]) for key in self]
+
+    def iterkeys(self):
+        'od.iterkeys() -> an iterator over the keys in od'
+        return iter(self)
+
+    def itervalues(self):
+        'od.itervalues -> an iterator over the values in od'
+        for k in self:
+            yield self[k]
+
+    def iteritems(self):
+        'od.iteritems -> an iterator over the (key, value) items in od'
+        for k in self:
+            yield (k, self[k])
+
+    def update(*args, **kwds):
+        '''od.update(E, **F) -> None.  Update od from dict/iterable E and F.
+
+        If E is a dict instance, does:           for k in E: od[k] = E[k]
+        If E has a .keys() method, does:         for k in E.keys(): od[k] = E[k]
+        Or if E is an iterable of items, does:   for k, v in E: od[k] = v
+        In either case, this is followed by:     for k, v in F.items(): od[k] = v
+
+        '''
+        if len(args) > 2:
+            raise TypeError('update() takes at most 2 positional '
+                            'arguments (%d given)' % (len(args),))
+        elif not args:
+            raise TypeError('update() takes at least 1 argument (0 given)')
+        self = args[0]
+        # Make progressively weaker assumptions about "other"
+        other = ()
+        if len(args) == 2:
+            other = args[1]
+        if isinstance(other, dict):
+            for key in other:
+                self[key] = other[key]
+        elif hasattr(other, 'keys'):
+            for key in other.keys():
+                self[key] = other[key]
+        else:
+            for key, value in other:
+                self[key] = value
+        for key, value in kwds.items():
+            self[key] = value
+
+    __update = update  # let subclasses override update without breaking __init__
+
+    __marker = object()
+
+    def pop(self, key, default=__marker):
+        '''od.pop(k[,d]) -> v, remove specified key and return the corresponding value.
+        If key is not found, d is returned if given, otherwise KeyError is raised.
+
+        '''
+        if key in self:
+            result = self[key]
+            del self[key]
+            return result
+        if default is self.__marker:
+            raise KeyError(key)
+        return default
+
+    def setdefault(self, key, default=None):
+        'od.setdefault(k[,d]) -> od.get(k,d), also set od[k]=d if k not in od'
+        if key in self:
+            return self[key]
+        self[key] = default
+        return default
+
+    def __repr__(self, _repr_running={}):
+        'od.__repr__() <==> repr(od)'
+        call_key = id(self), _get_ident()
+        if call_key in _repr_running:
+            return '...'
+        _repr_running[call_key] = 1
+        try:
+            if not self:
+                return '%s()' % (self.__class__.__name__,)
+            return '%s(%r)' % (self.__class__.__name__, self.items())
+        finally:
+            del _repr_running[call_key]
+
+    def __reduce__(self):
+        'Return state information for pickling'
+        items = [[k, self[k]] for k in self]
+        inst_dict = vars(self).copy()
+        for k in vars(OrderedDict()):
+            inst_dict.pop(k, None)
+        if inst_dict:
+            return (self.__class__, (items,), inst_dict)
+        return self.__class__, (items,)
+
+    def copy(self):
+        'od.copy() -> a shallow copy of od'
+        return self.__class__(self)
+
+    @classmethod
+    def fromkeys(cls, iterable, value=None):
+        '''OD.fromkeys(S[, v]) -> New ordered dictionary with keys from S
+        and values equal to v (which defaults to None).
+
+        '''
+        d = cls()
+        for key in iterable:
+            d[key] = value
+        return d
+
+    def __eq__(self, other):
+        '''od.__eq__(y) <==> od==y.  Comparison to another OD is order-sensitive
+        while comparison to a regular mapping is order-insensitive.
+
+        '''
+        if isinstance(other, OrderedDict):
+            return len(self)==len(other) and self.items() == other.items()
+        return dict.__eq__(self, other)
+
+    def __ne__(self, other):
+        return not self == other
+
+    # -- the following methods are only used in Python 2.7 --
+
+    def viewkeys(self):
+        "od.viewkeys() -> a set-like object providing a view on od's keys"
+        return KeysView(self)
+
+    def viewvalues(self):
+        "od.viewvalues() -> an object providing a view on od's values"
+        return ValuesView(self)
+
+    def viewitems(self):
+        "od.viewitems() -> a set-like object providing a view on od's items"
+        return ItemsView(self)