X-Git-Url: https://git.openstreetmap.org/rails.git/blobdiff_plain/81ca9cfabf6f9f720127a1fcc68ec709af277730..8ae5d94b2f16d6f2cf1739e19ebc3793a18a0a4a:/app/models/changeset.rb

diff --git a/app/models/changeset.rb b/app/models/changeset.rb
index 4a4d12124..3f6df27f6 100644
--- a/app/models/changeset.rb
+++ b/app/models/changeset.rb
@@ -4,46 +4,83 @@ class Changeset < ActiveRecord::Base
   belongs_to :user
 
   has_many :changeset_tags, :foreign_key => 'id'
-  
+
   has_many :nodes
   has_many :ways
   has_many :relations
   has_many :old_nodes
   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
+
+  before_save :update_closed_at
+
   # 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 
+  # 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
+
+  def set_closed_time_now
+    if is_open?
+      self.closed_at = Time.now.getutc
+    end
   end
 
   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
-          cs.created_at = Time.now
-        end
-
-        pt.find('tag').each do |tag|
-          cs.add_tag_keyval(tag['k'], tag['v'])
-        end
+        return Changeset.from_xml_node(pt, create)
       end
-    rescue Exception => ex
-      cs = nil
+      raise OSM::APIBadXMLError.new("changeset", xml, "XML doesn't contain an osm/changeset element.")
+    rescue LibXML::XML::Error, ArgumentError => ex
+      raise OSM::APIBadXMLError.new("changeset", xml, ex.message)
+    end
+  end
+
+  def self.from_xml_node(pt, create=false)
+    cs = Changeset.new
+    if create
+      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|
+      raise OSM::APIBadXMLError.new("changeset", pt, "tag is missing key") if tag['k'].nil?
+      raise OSM::APIBadXMLError.new("changeset", pt, "tag is missing value") if tag['v'].nil?
+      cs.add_tag_keyval(tag['k'], tag['v'])
     end
 
     return cs
@@ -56,26 +93,53 @@ class Changeset < ActiveRecord::Base
     @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, 
+  # returns area of the changset bbox as a rough comparitive quantity for use of changset displays
+  def area
+     if has_valid_bbox?
+       (max_lon - min_lon) * (max_lat - min_lat)
+     else
+       0
+     end
+  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 
+  # 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]
+    # only try to update the bbox if there is a value for every coordinate
+    # which there will be from the previous line as long as both array and
+    # bbox are all non-nil. 
+    if has_valid_bbox? and array.all?
+      # FIXME - this looks nasty and violates DRY... is there any prettier
+      # way to do this?
+      @bbox[0] = [-180 * GeoRecord::SCALE, array[0] + EXPAND * (@bbox[0] - @bbox[2])].max if array[0] < @bbox[0]
+      @bbox[1] = [ -90 * GeoRecord::SCALE, array[1] + EXPAND * (@bbox[1] - @bbox[3])].max if array[1] < @bbox[1]
+      @bbox[2] = [ 180 * GeoRecord::SCALE, array[2] + EXPAND * (@bbox[2] - @bbox[0])].min if array[2] > @bbox[2]
+      @bbox[3] = [  90 * GeoRecord::SCALE, array[3] + EXPAND * (@bbox[3] - @bbox[1])].min 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
+  end
 
-    # 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
+  ##
+  # 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
@@ -98,19 +162,20 @@ class Changeset < ActiveRecord::Base
 
   def add_tag_keyval(k, v)
     @tags = Hash.new unless @tags
+
+    # duplicate tags are now forbidden, so we can't allow values
+    # in the hash to be overwritten.
+    raise OSM::APIDuplicateTagsError.new("changeset", self.id, k) if @tags.include? k
+
     @tags[k] = v
   end
 
   def save_with_tags!
-    t = Time.now
-
+    # do the changeset update and the changeset tags update in the
+    # same transaction to ensure consistency.
     Changeset.transaction do
-      # fixme update modified_at time?
-      # FIXME there is no modified_at time, should it be added
       self.save!
-    end
 
-    ChangesetTag.transaction do
       tags = self.tags
       ChangesetTag.delete_all(['id = ?', self.id])
 
@@ -123,13 +188,27 @@ class Changeset < ActiveRecord::Base
       end
     end
   end
-  
+
+  ##
+  # 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.
+  def update_closed_at
+    if self.is_open?
+      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
+    end
+  end
+
   def to_xml
     doc = OSM::API.new.get_xml_doc
     doc.root << to_xml_node()
     return doc
   end
-  
+
   def to_xml_node(user_display_name_cache = nil)
     el1 = XML::Node.new 'changeset'
     el1['id'] = self.id.to_s
@@ -153,19 +232,41 @@ class Changeset < ActiveRecord::Base
       el2['v'] = v.to_s
       el1 << el2
     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
 
     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
+
+  ##
+  # 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