[gnue] r6922 - trunk/gnue-appserver/src

[johannes]

Author: johannes
Date: 2005-01-25 04:15:23 -0600 (Tue, 25 Jan 2005)
New Revision: 6922

Modified:
   trunk/gnue-appserver/src/geasList.py
   trunk/gnue-appserver/src/geasSession.py
Log:
Implemented <exist> conditions


Modified: trunk/gnue-appserver/src/geasList.py
===================================================================
--- trunk/gnue-appserver/src/geasList.py        2005-01-25 10:14:57 UTC (rev 
6921)
+++ trunk/gnue-appserver/src/geasList.py        2005-01-25 10:15:23 UTC (rev 
6922)
@@ -24,7 +24,10 @@
 import geasInstance
 import string
 import time
+import copy
 
+from gnue.common.datasources import GConditions
+
 # =============================================================================
 # List class
 # =============================================================================
@@ -50,6 +53,11 @@
     self.__asSorting  = asSort          # additional sortorder of this list
     self.__length     = 0
 
+    # If we have a condition to process, make sure we set a proper callback for
+    # exist-conditions
+    if self.__condition is not None:
+      for item in self.__condition.findChildrenOfType ('GCexist', True, True):
+        item.callback = self.__evaluateExist
 
 
   # ---------------------------------------------------------------------------
@@ -268,3 +276,37 @@
 
     self.__instances  = []
     self.__unsorted   = []
+
+
+  # ---------------------------------------------------------------------------
+  # Evaluate an exist condition for an instance
+  # ---------------------------------------------------------------------------
+
+  def __evaluateExist (self, caller, lookup):
+    """
+    This function evaluates an exist-condition for the instance given in
+    'lookup'.
+    @param caller: GCexist instance defining the condition
+    @param lookup: geasInstance instance to be evaluated
+    @return: True if there are instance matching the condition, False otherwise
+    """
+
+    linkCond = GConditions.buildConditionFromDict ( \
+                              {caller.detaillink: lookup [caller.masterlink]})
+
+    parent = linkCond._children [0]
+
+    # If the condition has a subcondition we need to 'copy' this subcondition
+    # elements. This is to prevent appserver's changes made to the condition
+    # elements later, disturbing the following request.
+    if len (caller._children):
+      for c in caller._children:
+        new = GConditions.buildTreeFromList (c.prefixNotation ())
+        new.parent = parent
+        parent._children.append (new)
+
+    resList = self.__session.request (caller.table, linkCond, [], [u'gnue_id'])
+    result  = self.__session.fetch (resList, 0, 1)
+
+    return len (result) > 0
+

Modified: trunk/gnue-appserver/src/geasSession.py
===================================================================
--- trunk/gnue-appserver/src/geasSession.py     2005-01-25 10:14:57 UTC (rev 
6921)
+++ trunk/gnue-appserver/src/geasSession.py     2005-01-25 10:15:23 UTC (rev 
6922)
@@ -794,10 +794,13 @@
   def __dbHandlesTree (self, tree, classdef):
     """
     This function traverses the given condition tree and determines if it can
-    be handled be the datasource completely.
+    be handled by the datasource completely.
     """
     if isinstance (tree, GConditions.GCField):
       return self.__usable (tree, classdef)
+    # a backend cannot handle an exist-condition (yet)
+    elif isinstance (tree, GConditions.GCexist):
+      return False
     else:
       for child in tree._children:
         res = self.__dbHandlesTree (child, classdef)
@@ -845,7 +848,10 @@
     """
     if isinstance (tree, GConditions.GCField):
       self.__getFieldname (classdef, tree.name, content, True)
-    else:
+
+    # Note: we do not add fields from an exist-condition to the current
+    # content-dictionary, cause they will be handled by an extra request ()
+    elif not isinstance (tree, GConditions.GCexist):
       for child in tree._children:
         self.__addConditionToContent (classdef, content, child)