Don't order by id when getting last records

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

diff --git a/app/models/changeset.rb b/app/models/changeset.rb
index 04023ae2b94a6f883966b4aead228ac57508d439..e6bde19a50d8562f63e12e44be146a72e5905ac9 100644 (file)
--- a/app/models/changeset.rb
+++ b/app/models/changeset.rb
@@ -1,10 +1,38 @@
-class Changeset < ActiveRecord::Base
-  require 'xml/libxml'
+# == Schema Information
+#
+# Table name: changesets
+#
+#  id          :bigint(8)        not null, primary key
+#  user_id     :bigint(8)        not null
+#  created_at  :datetime         not null
+#  min_lat     :integer
+#  max_lat     :integer
+#  min_lon     :integer
+#  max_lon     :integer
+#  closed_at   :datetime         not null
+#  num_changes :integer          default(0), not null
+#
+# Indexes
+#
+#  changesets_bbox_idx                        (min_lat,max_lat,min_lon,max_lon) USING gist
+#  changesets_closed_at_idx                   (closed_at)
+#  changesets_created_at_idx                  (created_at)
+#  changesets_user_id_created_at_idx          (user_id,created_at)
+#  changesets_user_id_id_idx                  (user_id,id)
+#  index_changesets_on_user_id_and_closed_at  (user_id,closed_at)
+#
+# Foreign Keys
+#
+#  changesets_user_id_fkey  (user_id => users.id)
+#
+
+class Changeset < ApplicationRecord
+  require "xml/libxml"
+
+  belongs_to :user, :counter_cache => true
+
+  has_many :changeset_tags

 
 

-  belongs_to :user
-
-  has_many :changeset_tags, :foreign_key => 'id'
-  

   has_many :nodes
   has_many :ways
   has_many :relations
   has_many :nodes
   has_many :ways
   has_many :relations


@@ -12,107 +40,197 @@ class Changeset < ActiveRecord::Base
   has_many :old_ways
   has_many :old_relations
 
   has_many :old_ways
   has_many :old_relations
 

-  def self.from_xml(xml, create=false)
-    begin
-      p = XML::Parser.new
-      p.string = xml
-      doc = p.parse
+  has_many :comments, -> { where(:visible => true).order(:created_at) }, :class_name => "ChangesetComment"
+  has_and_belongs_to_many :subscribers, :class_name => "User", :join_table => "changesets_subscribers", :association_foreign_key => "subscriber_id"
+
+  validates :id, :uniqueness => true, :presence => { :on => :update },
+                 :numericality => { :on => :update, :only_integer => true }
+  validates :num_changes, :presence => true,
+                          :numericality => { :only_integer => true,
+                                             :greater_than_or_equal_to => 0 }
+  validates :created_at, :closed_at, :presence => true
+  validates :min_lat, :max_lat, :min_lon, :max_lat, :allow_nil => true,
+                                                    :numericality => { :only_integer => true }
+
+  before_save :update_closed_at
+
+  # maximum number of elements allowed in a changeset
+  MAX_ELEMENTS = 10000
+
+  # 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 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.
+    (closed_at > Time.now.utc) && (num_changes <= MAX_ELEMENTS)
+  end

 
 

-      cs = Changeset.new
+  def set_closed_time_now
+    self.closed_at = Time.now.utc if open?
+  end

 
 

-      doc.find('//osm/changeset').each do |pt|
-        if create
-          cs.created_at = Time.now
-        end
+  def self.from_xml(xml, create: false)
+    p = XML::Parser.string(xml, :options => XML::Parser::Options::NOERROR)
+    doc = p.parse
+    pt = doc.find_first("//osm/changeset")

 
 

-        pt.find('tag').each do |tag|
-          cs.add_tag_keyval(tag['k'], tag['v'])
-        end
-      end
-    rescue Exception => ex
-    print "noes "+ ex.to_s + "\n"
-      cs = nil
+    if pt
+      Changeset.from_xml_node(pt, :create => create)
+    else
+      raise OSM::APIBadXMLError.new("changeset", xml, "XML doesn't contain an osm/changeset element.")

     end
     end

+  rescue LibXML::XML::Error, ArgumentError => e
+    raise OSM::APIBadXMLError.new("changeset", xml, e.message)
+  end
+
+  def self.from_xml_node(pt, create: false)
+    cs = Changeset.new
+    if create
+      cs.created_at = Time.now.utc
+      # 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
+
+    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 ||= BoundingBox.new(min_lon, min_lat, max_lon, max_lat)
+  end
+
+  def bbox_valid?
+    bbox.complete?
+  end
+
+  ##
+  # expand the bounding box to include the given bounding box.
+  def update_bbox!(bbox_update)
+    bbox.expand!(bbox_update)
+
+    raise OSM::APISizeLimitExceeded if bbox.linear_size > size_limit

 
 

-    return cs
+    # 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.to_a.collect(&:round) if bbox.complete?
+  end
+
+  ##
+  # the number of elements is also passed in so that we can ensure that
+  # a single changeset doesn't contain too many elements.
+  def add_changes!(elements)
+    self.num_changes += elements

   end
 
   def tags
     unless @tags
       @tags = {}
   end
 
   def tags
     unless @tags
       @tags = {}

-      self.changeset_tags.each do |tag|
+      changeset_tags.each do |tag|

         @tags[tag.k] = tag.v
       end
     end
     @tags
   end
 
         @tags[tag.k] = tag.v
       end
     end
     @tags
   end
 

-  def tags=(t)
-    @tags = t
-  end
+  attr_writer :tags

 
   def add_tag_keyval(k, v)
 
   def add_tag_keyval(k, v)

-    @tags = Hash.new unless @tags
+    @tags ||= {}
+
+    # duplicate tags are now forbidden, so we can't allow values
+    # in the hash to be overwritten.
+    raise OSM::APIDuplicateTagsError.new("changeset", id, k) if @tags.include? k
+

     @tags[k] = v
   end
 
   def save_with_tags!
     @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
     Changeset.transaction do

-      # fixme update modified_at time?
-      self.save!
-    end
+      save!

 
 

-    ChangesetTag.transaction do

       tags = self.tags
       tags = self.tags

-      ChangesetTag.delete_all(['id = ?', self.id])
+      ChangesetTag.where(:changeset => id).delete_all

 
 

-      tags.each do |k,v|
+      tags.each do |k, v|

         tag = ChangesetTag.new
         tag = ChangesetTag.new

+        tag.changeset_id = id

         tag.k = k
         tag.v = v
         tag.k = k
         tag.v = v

-        tag.id = self.id

         tag.save!
       end
     end
   end
         tag.save!
       end
     end
   end

-  
-  def to_xml
-    doc = OSM::API.new.get_xml_doc
-    doc.root << to_xml_node()
-    return doc
+
+  ##
+  # 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 open?
+      self.closed_at = if (closed_at - created_at) > (MAX_TIME_OPEN - IDLE_TIMEOUT)
+                         created_at + MAX_TIME_OPEN
+                       else
+                         Time.now.utc + IDLE_TIMEOUT
+                       end
+    end

   end
   end

-  def to_xml_node(user_display_name_cache = nil)
-    el1 = XML::Node.new 'changeset'
-    el1['id'] = self.id.to_s

 
 

-    user_display_name_cache = {} if user_display_name_cache.nil?
+  ##
+  # 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.
+    raise OSM::APIUserChangesetMismatchError unless user.id == user_id

 
 

-    if user_display_name_cache and user_display_name_cache.key?(self.user_id)
-      # use the cache if available
-    elsif self.user.data_public?
-      user_display_name_cache[self.user_id] = self.user.display_name
-    else
-      user_display_name_cache[self.user_id] = nil
-    end
+    # can't change a closed changeset
+    raise OSM::APIChangesetAlreadyClosedError, self unless open?

 
 

-    el1['user'] = user_display_name_cache[self.user_id] unless user_display_name_cache[self.user_id].nil?
+    # copy the other's tags
+    self.tags = other.tags

 
 

-    self.tags.each do |k,v|
-      el2 = XML::Node.new('tag')
-      el2['k'] = k.to_s
-      el2['v'] = v.to_s
-      el1 << el2
-    end
-    
-    el1['created_at'] = self.created_at.xmlschema
-    el1['open'] = self.open.to_s
+    save_with_tags!
+  end

 
 

-    # 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
+  def subscribe(user)
+    subscribers << user
+  end
+
+  def unsubscribe(user)
+    subscribers.delete(user)
+  end
+
+  def subscribed?(user)
+    subscribers.exists?(user.id)
+  end

 
 

-    return el1
+  def size_limit
+    @size_limit ||= ActiveRecord::Base.connection.select_value(
+      "SELECT api_size_limit($1)", "api_size_limit", [user_id]
+    )

   end
 end
   end
 end