+++ /dev/null
-#!/usr/bin/ruby
-
-require "rubygems"
-require "proj4"
-require "xml/libxml"
-require "set"
-require "time"
-
-module Expire
- # projection object to go from latlon -> spherical mercator
- PROJ = Proj4::Projection.new(["+proj=merc", "+a=6378137", "+b=6378137",
- "+lat_ts=0.0", "+lon_0=0.0", "+x_0=0.0",
- "+y_0=0", "+k=1.0", "+units=m",
- "+nadgrids=@null", "+no_defs +over"])
-
- # width/height of the spherical mercator projection
- SIZE = 40075016.6855784
- # the size of the meta tile blocks
- METATILE = 8
- # the directory root for meta tiles
- HASH_ROOT = "/tiles/default/".freeze
- # node cache file
- NODE_CACHE_FILE = "/store/database/nodes".freeze
-
- # turns a spherical mercator coord into a tile coord
- def self.tile_from_merc(point, zoom)
- # renormalise into unit space [0,1]
- point.x = 0.5 + point.x / SIZE
- point.y = 0.5 - point.y / SIZE
- # transform into tile space
- point.x = point.x * 2**zoom
- point.y = point.y * 2**zoom
- # chop of the fractional parts
- [point.x.to_int, point.y.to_int, zoom]
- end
-
- # turns a latlon -> tile x,y given a zoom level
- def self.tile_from_latlon(latlon, zoom)
- # first convert to spherical mercator
- point = PROJ.forward(latlon)
- tile_from_merc(point, zoom)
- end
-
- # this must match the definition of xyz_to_meta in mod_tile
- def self.xyz_to_meta(x, y, z)
- # mask off the final few bits
- x &= ~(METATILE - 1)
- y &= ~(METATILE - 1)
- # generate the path
- hash_path = (0..4).collect do |i|
- (((x >> 4 * i) & 0xf) << 4) | ((y >> 4 * i) & 0xf)
- end.reverse.join("/")
- z.to_s + "/" + hash_path + ".meta"
- end
-
- # time to reset to, some very stupidly early time, before OSM started
- EXPIRY_TIME = Time.parse("2000-01-01 00:00:00")
-
- # expire the meta tile by setting the modified time back
- def self.expire_meta(meta)
- puts "Expiring #{meta}"
- File.utime(EXPIRY_TIME, EXPIRY_TIME, meta)
- end
-
- def self.expire(change_file, min_zoom, max_zoom, tile_dirs)
- do_expire(change_file, min_zoom, max_zoom) do |set|
- new_set = Set.new
- meta_set = Set.new
-
- # turn all the tiles into expires, putting them in the set
- # 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(xy[0], xy[1], xy[2])
-
- # check each style working out what needs expiring
- tile_dirs.each do |tile_dir|
- meta_set.add(tile_dir + "/" + meta) if File.exist?(tile_dir + "/" + meta)
- end
-
- # add the parent into the set for the next round
- new_set.add([xy[0] / 2, xy[1] / 2, xy[2] - 1])
- end
-
- # expire all meta tiles
- meta_set.each do |meta|
- expire_meta(meta)
- end
-
- # return the new set, consisting of all the parents
- new_set
- end
- end
-
- def self.do_expire(change_file, min_zoom, max_zoom, &_)
- # read in the osm change file
- doc = XML::Document.file(change_file)
-
- # hash map to contain all the nodes
- nodes = {}
-
- # we put all the nodes into the hash, as it doesn't matter whether the node was
- # added, deleted or modified - the tile will need updating anyway.
- doc.find("//node").each do |node|
- lat = node["lat"].to_f
- lat = -85 if lat < -85
- lat = 85 if lat > 85
- point = Proj4::Point.new(Math::PI * node["lon"].to_f / 180,
- Math::PI * lat / 180)
- nodes[node["id"].to_i] = tile_from_latlon(point, max_zoom)
- end
-
- # now we look for all the ways that have changed and put all of their nodes into
- # the hash too. this will add too many nodes, as it is possible a long way will be
- # changed at only a portion of its length. however, due to the non-local way that
- # mapnik does text placement, it may stil not be enough.
- #
- # 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.
- node_cache = NodeCache.new(NODE_CACHE_FILE)
- doc.find("//way/nd").each do |node|
- node_id = node["ref"].to_i
-
- next if nodes.include? node_id
-
- # this is a node referenced but not added, modified or deleted, so it should
- # 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
- end
- node_cache.close
-
- # create a set of all the tiles at the maximum zoom level which are touched by
- # any of the nodes we've collected. we'll create the tiles at other zoom levels
- # by a simple recursion.
- set = Set.new nodes.values
-
- # expire tiles and shrink to the set of parents
- max_zoom.downto(min_zoom) do |_|
- # allow the block to work on the set, returning the set at the next
- # zoom level
- 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 = File.new(filename, "r")
-
- throw "Unexpected format" unless @cache.sysread(4).unpack("l").first == 1
- throw "Unexpected ID size" unless @cache.sysread(4).unpack("l").first == 8
-
- @max_id = @cache.sysread(8).unpack("q").first
- end
-
- # close the cache
- def close
- @cache.close
- end
-
- # lookup a node
- def [](id)
- if id <= @max_id
- offset = 16 + id * 8
-
- @cache.sysseek(offset)
-
- lon, lat = @cache.sysread(8).unpack("ll")
-
- node = Node.new(lon, lat) if lon != -2147483648 && lat != -2147483648
- end
-
- node
- end
- end
-end
projects / chef.git / blobdiff