require 'proj4'
require 'xml/libxml'
require 'set'
-require 'pg'
require 'time'
+require 'mmap'
module Expire
# projection object to go from latlon -> spherical mercator
METATILE = 8
# the directory root for meta tiles
HASH_ROOT = "/tiles/default/"
- # database parameters
- DBNAME="gis"
- DBHOST=""
- #DBPORT=5432
- DBPORT=5432
- DBTABLE="planet_osm_nodes"
+ # node cache file
+ NODE_CACHE_FILE="/store/database/nodes"
# turns a spherical mercator coord into a tile coord
def Expire.tile_from_merc(point, zoom)
# so that we don't expire things multiple times
set.each do |xy|
# this has to match the routine in mod_tile
- meta = xyz_to_meta(HASH_ROOT, xy[0], xy[1], xy[2])
+ meta = xyz_to_meta(xy[0], xy[1], xy[2])
# check each style working out what needs expiring
tile_dirs.each do |tile_dir|
# also, we miss cases where nodes are deleted from ways where that node is not
# itself deleted and the coverage of the point set isn't enough to encompass the
# change.
- conn = PG::Connection.new(:host => DBHOST, :port => DBPORT, :dbname => DBNAME)
+ node_cache = NodeCache.new(NODE_CACHE_FILE)
doc.find('//way/nd').each do |node|
node_id = node['ref'].to_i
unless nodes.include? node_id
# this is a node referenced but not added, modified or deleted, so it should
- # still be in the postgis DB.
- res = conn.query("select lon, lat from #{DBTABLE} where id=#{node_id};")
-
- # loop over results, adding tiles to the change set
- res.each do |row|
- point = Proj4::Point.new(row[0].to_f / 100.0, row[1].to_f / 100.0)
+ # still be in the node cache.
+ if entry = node_cache[node_id]
+ point = Proj4::Point.new(entry.lon, entry.lat)
nodes[node_id] = tile_from_merc(point, max_zoom)
end
-
- # Discard results
- res.clear
end
end
set = yield set
end
end
+
+ # wrapper to access the osm2pgsql node cache
+ class NodeCache
+ # node cache entry
+ class Node
+ attr_reader :lon, :lat
+
+ def initialize(lon, lat)
+ @lat = lat.to_f / 100.0
+ @lon = lon.to_f / 100.0
+ end
+ end
+
+ # open the cache
+ def initialize(filename)
+ @cache = Mmap.new(filename)
+
+ throw "Unexpected format" unless @cache[0..3].unpack("l").first == 1
+ throw "Unexpected ID size" unless @cache[4..7].unpack("l").first == 8
+
+ @max_id = @cache[8..15].unpack("q").first
+ end
+
+ # lookup a node
+ def [](id)
+ if id <= @max_id
+ offset = 16 + id * 8
+
+ lon, lat = @cache[offset .. offset+7].unpack("ll")
+
+ if lon != -2147483648 && lat != -2147483648
+ node = Node.new(lon, lat)
+ end
+ end
+
+ node
+ end
+ end
end