per-object-permissions: Merged to trunk [5486] NOTE: Not fully tested, will be working on this over the next few weeks.

git-svn-id: http://code.djangoproject.com/svn/django/branches/per-object-permissions@5488 bcc190cf-cafb-0310-a4f2-bffc1f526a37

1 files changed, 178 insertions, 18 deletions

diff --git a/django/newforms/models.py b/django/newforms/models.py
index 6b111d7ee1..d51b06c78c 100644
--- a/django/newforms/models.py
+++ b/django/newforms/models.py
@@ -3,36 +3,196 @@ Helper functions for creating Form classes from Django models
 and database field objects.
 """
 
-from forms import BaseForm, DeclarativeFieldsMetaclass, SortedDictFromList
+from django.utils.translation import gettext
 
-__all__ = ('form_for_model', 'form_for_fields')
+from util import ValidationError
+from forms import BaseForm, SortedDictFromList
+from fields import Field, ChoiceField
+from widgets import Select, SelectMultiple, MultipleHiddenInput
 
-def create(self, save=True):
-    "Creates and returns model instance according to self.clean_data."
-    if self.errors:
-        raise ValueError("The %s could not be created because the data didn't validate." % self._model._meta.object_name)
-    obj = self._model(**self.clean_data)
-    if save:
-        obj.save()
-    return obj
+__all__ = (
+    'save_instance', 'form_for_model', 'form_for_instance', 'form_for_fields',
+    'ModelChoiceField', 'ModelMultipleChoiceField'
+)
 
-def form_for_model(model, form=None):
+def save_instance(form, instance, fields=None, fail_message='saved', commit=True):
+    """
+    Saves bound Form ``form``'s cleaned_data into model instance ``instance``.
+
+    If commit=True, then the changes to ``instance`` will be saved to the
+    database. Returns ``instance``.
+    """
+    from django.db import models
+    opts = instance.__class__._meta
+    if form.errors:
+        raise ValueError("The %s could not be %s because the data didn't validate." % (opts.object_name, fail_message))
+    cleaned_data = form.cleaned_data
+    for f in opts.fields:
+        if not f.editable or isinstance(f, models.AutoField) or not f.name in cleaned_data:
+            continue
+        if fields and f.name not in fields:
+            continue
+        setattr(instance, f.name, cleaned_data[f.name])
+    if commit:
+        instance.save()
+        for f in opts.many_to_many:
+            if fields and f.name not in fields:
+                continue
+            if f.name in cleaned_data:
+                setattr(instance, f.attname, cleaned_data[f.name])
+    # GOTCHA: If many-to-many data is given and commit=False, the many-to-many
+    # data will be lost. This happens because a many-to-many options cannot be
+    # set on an object until after it's saved. Maybe we should raise an
+    # exception in that case.
+    return instance
+
+def make_model_save(model, fields, fail_message):
+    "Returns the save() method for a Form."
+    def save(self, commit=True):
+        return save_instance(self, model(), fields, fail_message, commit)
+    return save
+    
+def make_instance_save(instance, fields, fail_message):
+    "Returns the save() method for a Form."
+    def save(self, commit=True):
+        return save_instance(self, instance, fields, fail_message, commit)
+    return save
+
+def form_for_model(model, form=BaseForm, fields=None, formfield_callback=lambda f: f.formfield()):
     """
     Returns a Form class for the given Django model class.
 
-    Provide 'form' if you want to use a custom BaseForm subclass.
+    Provide ``form`` if you want to use a custom BaseForm subclass.
+
+    Provide ``formfield_callback`` if you want to define different logic for
+    determining the formfield for a given database field. It's a callable that
+    takes a database Field instance and returns a form Field instance.
     """
     opts = model._meta
     field_list = []
     for f in opts.fields + opts.many_to_many:
-        formfield = f.formfield()
+        if not f.editable:
+            continue
+        if fields and not f.name in fields:
+            continue
+        formfield = formfield_callback(f)
         if formfield:
             field_list.append((f.name, formfield))
-    fields = SortedDictFromList(field_list)
-    form = form or BaseForm
-    return type(opts.object_name + 'Form', (form,), {'fields': fields, '_model': model, 'create': create})
+    base_fields = SortedDictFromList(field_list)
+    return type(opts.object_name + 'Form', (form,), 
+        {'base_fields': base_fields, '_model': model, 'save': make_model_save(model, fields, 'created')})
+
+def form_for_instance(instance, form=BaseForm, fields=None, formfield_callback=lambda f, **kwargs: f.formfield(**kwargs)):
+    """
+    Returns a Form class for the given Django model instance.
+
+    Provide ``form`` if you want to use a custom BaseForm subclass.
+
+    Provide ``formfield_callback`` if you want to define different logic for
+    determining the formfield for a given database field. It's a callable that
+    takes a database Field instance, plus **kwargs, and returns a form Field
+    instance with the given kwargs (i.e. 'initial').
+    """
+    model = instance.__class__
+    opts = model._meta
+    field_list = []
+    for f in opts.fields + opts.many_to_many:
+        if not f.editable:
+            continue
+        if fields and not f.name in fields:
+            continue
+        current_value = f.value_from_object(instance)
+        formfield = formfield_callback(f, initial=current_value)
+        if formfield:
+            field_list.append((f.name, formfield))
+    base_fields = SortedDictFromList(field_list)
+    return type(opts.object_name + 'InstanceForm', (form,),
+        {'base_fields': base_fields, '_model': model, 'save': make_instance_save(instance, fields, 'changed')})
 
 def form_for_fields(field_list):
     "Returns a Form class for the given list of Django database field instances."
-    fields = SortedDictFromList([(f.name, f.formfield()) for f in field_list])
-    return type('FormForFields', (BaseForm,), {'fields': fields})
+    fields = SortedDictFromList([(f.name, f.formfield()) for f in field_list if f.editable])
+    return type('FormForFields', (BaseForm,), {'base_fields': fields})
+
+class QuerySetIterator(object):
+    def __init__(self, queryset, empty_label, cache_choices):
+        self.queryset, self.empty_label, self.cache_choices = queryset, empty_label, cache_choices
+
+    def __iter__(self):
+        if self.empty_label is not None:
+            yield (u"", self.empty_label)
+        for obj in self.queryset:
+            yield (obj._get_pk_val(), str(obj))
+        # Clear the QuerySet cache if required.
+        if not self.cache_choices:
+            self.queryset._result_cache = None
+
+class ModelChoiceField(ChoiceField):
+    "A ChoiceField whose choices are a model QuerySet."
+    # This class is a subclass of ChoiceField for purity, but it doesn't
+    # actually use any of ChoiceField's implementation.
+    def __init__(self, queryset, empty_label=u"---------", cache_choices=False,
+            required=True, widget=Select, label=None, initial=None, help_text=None):
+        self.queryset = queryset
+        self.empty_label = empty_label
+        self.cache_choices = cache_choices
+        # Call Field instead of ChoiceField __init__() because we don't need
+        # ChoiceField.__init__().
+        Field.__init__(self, required, widget, label, initial, help_text)
+        self.widget.choices = self.choices
+
+    def _get_choices(self):
+        # If self._choices is set, then somebody must have manually set
+        # the property self.choices. In this case, just return self._choices.
+        if hasattr(self, '_choices'):
+            return self._choices
+        # Otherwise, execute the QuerySet in self.queryset to determine the
+        # choices dynamically. Return a fresh QuerySetIterator that has not
+        # been consumed. Note that we're instantiating a new QuerySetIterator
+        # *each* time _get_choices() is called (and, thus, each time
+        # self.choices is accessed) so that we can ensure the QuerySet has not
+        # been consumed.
+        return QuerySetIterator(self.queryset, self.empty_label, self.cache_choices)
+
+    def _set_choices(self, value):
+        # This method is copied from ChoiceField._set_choices(). It's necessary
+        # because property() doesn't allow a subclass to overwrite only
+        # _get_choices without implementing _set_choices.
+        self._choices = self.widget.choices = list(value)
+
+    choices = property(_get_choices, _set_choices)
+
+    def clean(self, value):
+        Field.clean(self, value)
+        if value in ('', None):
+            return None
+        try:
+            value = self.queryset.model._default_manager.get(pk=value)
+        except self.queryset.model.DoesNotExist:
+            raise ValidationError(gettext(u'Select a valid choice. That choice is not one of the available choices.'))
+        return value
+
+class ModelMultipleChoiceField(ModelChoiceField):
+    "A MultipleChoiceField whose choices are a model QuerySet."
+    hidden_widget = MultipleHiddenInput
+    def __init__(self, queryset, cache_choices=False, required=True,
+            widget=SelectMultiple, label=None, initial=None, help_text=None):
+        super(ModelMultipleChoiceField, self).__init__(queryset, None, cache_choices,
+            required, widget, label, initial, help_text)
+
+    def clean(self, value):
+        if self.required and not value:
+            raise ValidationError(gettext(u'This field is required.'))
+        elif not self.required and not value:
+            return []
+        if not isinstance(value, (list, tuple)):
+            raise ValidationError(gettext(u'Enter a list of values.'))
+        final_values = []
+        for val in value:
+            try:
+                obj = self.queryset.model._default_manager.get(pk=val)
+            except self.queryset.model.DoesNotExist:
+                raise ValidationError(gettext(u'Select a valid choice. %s is not one of the available choices.') % val)
+            else:
+                final_values.append(obj)
+        return final_values