ibid

[rails.git] / app / models / changeset.rb

diff --git a/app/models/changeset.rb b/app/models/changeset.rb
index 446ca351de81cd4d574722630cc4785284ffd30f..fa2d556b10c00195a20d5f8670224a22475ebb7b 100644 (file)
--- a/app/models/changeset.rb
+++ b/app/models/changeset.rb
@@ -12,27 +12,60 @@ class Changeset < ActiveRecord::Base
   has_many :old_ways
   has_many :old_relations
   
   has_many :old_ways
   has_many :old_relations
   

-  validates_presence_of :user_id, :created_at
-  validates_inclusion_of :open, :in => [ true, false ]
-  
+  validates_presence_of :id, :on => :update
+  validates_presence_of :user_id, :created_at, :closed_at, :num_changes
+  validates_uniqueness_of :id
+  validates_numericality_of :id, :on => :update, :integer_only => true
+  validates_numericality_of :min_lat, :max_lat, :min_lon, :max_lat, :allow_nil => true, :integer_only => true
+  validates_numericality_of :user_id,  :integer_only => true
+  validates_numericality_of :num_changes, :integer_only => true, :greater_than_or_equal_to => 0
+  validates_associated :user
+
+  # over-expansion factor to use when updating the bounding box
+  EXPAND = 0.1
+
+  # maximum number of elements allowed in a changeset
+  MAX_ELEMENTS = 50000
+
+  # maximum time a changeset is allowed to be open for.
+  MAX_TIME_OPEN = 1.day
+
+  # idle timeout increment, one hour seems reasonable.
+  IDLE_TIMEOUT = 1.hour
+

   # Use a method like this, so that we can easily change how we
   # determine whether a changeset is open, without breaking code in at 
   # least 6 controllers
   def is_open?
   # Use a method like this, so that we can easily change how we
   # determine whether a changeset is open, without breaking code in at 
   # least 6 controllers
   def is_open?

-    return open
+    # a changeset is open (that is, it will accept further changes) when
+    # it has not yet run out of time and its capacity is small enough.
+    # note that this may not be a hard limit - due to timing changes and
+    # concurrency it is possible that some changesets may be slightly 
+    # longer than strictly allowed or have slightly more changes in them.
+    return ((closed_at > Time.now.getutc) and (num_changes <= MAX_ELEMENTS))

   end
 
   end
 

+  def set_closed_time_now
+    if is_open?
+      self.closed_at = Time.now.getutc
+    end
+  end
+  

   def self.from_xml(xml, create=false)
     begin
   def self.from_xml(xml, create=false)
     begin

-      p = XML::Parser.new
-      p.string = xml
+      p = XML::Parser.string(xml)

       doc = p.parse
 
       cs = Changeset.new
 
       doc.find('//osm/changeset').each do |pt|
         if create
       doc = p.parse
 
       cs = Changeset.new
 
       doc.find('//osm/changeset').each do |pt|
         if create

-          cs.created_at = Time.now
+          cs.created_at = Time.now.getutc
+          # initial close time is 1h ahead, but will be increased on each
+          # modification.
+          cs.closed_at = cs.created_at + IDLE_TIMEOUT
+          # initially we have no changes in a changeset
+          cs.num_changes = 0

         end
 
         pt.find('tag').each do |tag|
         end
 
         pt.find('tag').each do |tag|


@@ -46,6 +79,47 @@ class Changeset < ActiveRecord::Base
     return cs
   end
 
     return cs
   end
 

+  ##
+  # returns the bounding box of the changeset. it is possible that some
+  # or all of the values will be nil, indicating that they are undefined.
+  def bbox
+    @bbox ||= [ min_lon, min_lat, max_lon, max_lat ]
+  end
+  
+  def has_valid_bbox?
+    not bbox.include? nil
+  end
+
+  ##
+  # expand the bounding box to include the given bounding box. also, 
+  # expand a little bit more in the direction of the expansion, so that
+  # further expansions may be unnecessary. this is an optimisation 
+  # suggested on the wiki page by kleptog.
+  def update_bbox!(array)
+    # ensure that bbox is cached and has no nils in it. if there are any
+    # nils, just use the bounding box update to write over them.
+    @bbox = bbox.zip(array).collect { |a, b| a.nil? ? b : a }
+
+    # FIXME - this looks nasty and violates DRY... is there any prettier 
+    # way to do this? 
+    @bbox[0] = array[0] + EXPAND * (@bbox[0] - @bbox[2]) if array[0] < @bbox[0]
+    @bbox[1] = array[1] + EXPAND * (@bbox[1] - @bbox[3]) if array[1] < @bbox[1]
+    @bbox[2] = array[2] + EXPAND * (@bbox[2] - @bbox[0]) if array[2] > @bbox[2]
+    @bbox[3] = array[3] + EXPAND * (@bbox[3] - @bbox[1]) if array[3] > @bbox[3]
+
+    # update active record. rails 2.1's dirty handling should take care of
+    # whether this object needs saving or not.
+    self.min_lon, self.min_lat, self.max_lon, self.max_lat = @bbox
+  end
+
+  ##
+  # the number of elements is also passed in so that we can ensure that
+  # a single changeset doesn't contain too many elements. this, of course,
+  # destroys the optimisation described in the bbox method above.
+  def add_changes!(elements)
+    self.num_changes += elements
+  end
+

   def tags_as_hash
     return tags
   end
   def tags_as_hash
     return tags
   end


@@ -70,15 +144,21 @@ class Changeset < ActiveRecord::Base
   end
 
   def save_with_tags!
   end
 
   def save_with_tags!

-    t = Time.now
+    t = Time.now.getutc

 
 

+    # do the changeset update and the changeset tags update in the
+    # same transaction to ensure consistency.

     Changeset.transaction do
     Changeset.transaction do

-      # fixme update modified_at time?
-      # FIXME there is no modified_at time, should it be added
+      # set the auto-close time to be one hour in the future unless
+      # that would make it more than 24h long, in which case clip to
+      # 24h, as this has been decided is a reasonable time limit.
+      if (closed_at - created_at) > (MAX_TIME_OPEN - IDLE_TIMEOUT)
+        self.closed_at = created_at + MAX_TIME_OPEN
+      else
+        self.closed_at = Time.now.getutc + IDLE_TIMEOUT
+      end

       self.save!
       self.save!

-    end

 
 

-    ChangesetTag.transaction do

       tags = self.tags
       ChangesetTag.delete_all(['id = ?', self.id])
 
       tags = self.tags
       ChangesetTag.delete_all(['id = ?', self.id])
 


@@ -113,6 +193,7 @@ class Changeset < ActiveRecord::Base
     end
 
     el1['user'] = user_display_name_cache[self.user_id] unless user_display_name_cache[self.user_id].nil?
     end
 
     el1['user'] = user_display_name_cache[self.user_id] unless user_display_name_cache[self.user_id].nil?

+    el1['uid'] = self.user_id.to_s if self.user.data_public?

 
     self.tags.each do |k,v|
       el2 = XML::Node.new('tag')
 
     self.tags.each do |k,v|
       el2 = XML::Node.new('tag')


@@ -122,12 +203,39 @@ class Changeset < ActiveRecord::Base
     end
     
     el1['created_at'] = self.created_at.xmlschema
     end
     
     el1['created_at'] = self.created_at.xmlschema

-    el1['open'] = self.open.to_s
+    el1['closed_at'] = self.closed_at.xmlschema unless is_open?
+    el1['open'] = is_open?.to_s

 
 

-    # FIXME FIXME FIXME: This does not include changes yet! There is 
-    # currently no changeset_id column in the tables as far as I can tell,
-    # so this is just a scaffold to build on, not a complete to_xml
+    el1['min_lon'] = (bbox[0].to_f / GeoRecord::SCALE).to_s unless bbox[0].nil?
+    el1['min_lat'] = (bbox[1].to_f / GeoRecord::SCALE).to_s unless bbox[1].nil?
+    el1['max_lon'] = (bbox[2].to_f / GeoRecord::SCALE).to_s unless bbox[2].nil?
+    el1['max_lat'] = (bbox[3].to_f / GeoRecord::SCALE).to_s unless bbox[3].nil?
+    
+    # NOTE: changesets don't include the XML of the changes within them,
+    # they are just structures for tagging. to get the osmChange of a
+    # changeset, see the download method of the controller.

 
     return el1
   end
 
     return el1
   end

+
+  ##
+  # update this instance from another instance given and the user who is
+  # doing the updating. note that this method is not for updating the
+  # bounding box, only the tags of the changeset.
+  def update_from(other, user)
+    # ensure that only the user who opened the changeset may modify it.
+    unless user.id == self.user_id 
+      raise OSM::APIUserChangesetMismatchError.new
+    end
+    
+    # can't change a closed changeset
+    unless is_open?
+      raise OSM::APIChangesetAlreadyClosedError.new(self)
+    end
+
+    # copy the other's tags
+    self.tags = other.tags
+
+    save_with_tags!
+  end

 end
 end