From 16ec9aba7e94e628f22bcaeb3ecdd7916f3a3df5 Mon Sep 17 00:00:00 2001
From: lnu <lnu@f70e237a-67f3-0310-a06c-d2b8a7116972>
Date: Thu, 31 Mar 2005 22:08:32 +0000
Subject: first import

git-svn-id: svn+ssh://svn.gna.org/svn/feed2imap/trunk/feed2imap@5 f70e237a-67f3-0310-a06c-d2b8a7116972
---
 lib/feed2imap/cache.rb | 176 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 176 insertions(+)
 create mode 100644 lib/feed2imap/cache.rb

(limited to 'lib/feed2imap/cache.rb')

diff --git a/lib/feed2imap/cache.rb b/lib/feed2imap/cache.rb
new file mode 100644
index 0000000..1534483
--- /dev/null
+++ b/lib/feed2imap/cache.rb
@@ -0,0 +1,176 @@
+=begin
+Feed2Imap - RSS/Atom Aggregator uploading to an IMAP Server
+Copyright (c) 2005 Lucas Nussbaum <lucas@lucas-nussbaum.net>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+=end
+
+# This class manages a cache of items
+# (items which have already been seen)
+
+require 'digest/md5'
+
+class ItemCache
+  def initialize
+    @channels = {}
+    @@cacheidx = 0
+    self
+  end
+
+  # Returns the really new items amongst items
+  def get_new_items(id, items)
+    @channels[id] ||= CachedChannel::new
+    return @channels[id].get_new_items(items)
+  end
+
+  # Replace the existing cached items by those ones
+  def update_cache(id, items)
+    @channels[id] ||= CachedChannel::new
+    @channels[id].update(items)
+  end
+
+  # Get the last time the cache was updated
+  def get_last_check(id)
+    @channels[id] ||= CachedChannel::new
+    @channels[id].lastcheck
+  end
+
+  # Get the last time the cache was updated
+  def set_last_check(id, time)
+    @channels[id] ||= CachedChannel::new
+    @channels[id].lastcheck = time
+    self
+  end
+
+  # Load the cache from an IO stream
+  def load(io)
+    begin
+      @@cacheidx, @channels = Marshal.load(io)
+    rescue
+      @channels = Marshal.load(io)
+      @@cacheidx = 0
+    end
+  end
+
+  # Save the cache to an IO stream
+  def save(io)
+    Marshal.dump([@@cacheidx, @channels], io)
+  end
+  
+  # Return the number of channels in the cache
+  def nbchannels
+    @channels.length
+  end
+
+  # Return the number of items in the cache
+  def nbitems
+    nb = 0
+    @channels.each_value { |c|
+      nb += c.nbitems
+    }
+    nb
+  end
+
+  def ItemCache.getindex
+    i = @@cacheidx
+    @@cacheidx += 1
+    i
+  end
+end
+
+class CachedChannel
+  attr_accessor :lastcheck, :items
+
+  def initialize
+    @lastcheck = Time::at(0)
+    @items = []
+  end
+
+  # Returns the really new items amongst items
+  def get_new_items(items)
+    # set items' cached version if not set yet
+    newitems = []
+    updateditems = []
+    items.each { |i| i.cacheditem ||= CachedItem::new(i) }
+    items.each do |i|
+      # TODO rewrite with the fact that break can return a value
+      found = false
+      # Try to find a perfect match
+      @items.each do |j|
+        if i.cacheditem == j
+          i.cacheditem.index = j.index
+          found = true
+          break
+        end
+      end
+      next if found
+      # Try to find an updated item
+      @items.each do |j|
+        if i.link and i.link == j.link
+          # TODO use a better heuristic ?
+          i.cacheditem.index = j.index
+          i.cacheditem.updated = true
+          updateditems.push(i)
+          found = true
+          break
+        end
+      end
+      next if found
+      # add as new
+      i.cacheditem.create_index
+      newitems.push(i)
+    end
+    return [newitems, updateditems]
+  end
+
+  # Replace the existing cached items by those ones
+  def update(items)
+    @items = []
+    items.each do |i|
+      @items.push(i.cacheditem)
+    end
+    self
+  end
+
+  # returns the number of items
+  def nbitems
+    @items.length
+  end
+end
+
+# This class is the only thing kept in the cache
+class CachedItem
+  attr_reader :title, :link, :hash
+  attr_accessor :index
+  attr_accessor :updated
+
+  def initialize(item)
+    @title = item.title
+    @link = item.link
+    if item.content.nil?
+      @hash = nil
+    else
+      @hash = Digest::MD5.hexdigest(item.content.to_s)
+    end
+  end
+
+  def ==(other)
+    @title == other.title and @link == other.link and @hash == other.hash
+  end
+
+  def create_index
+    @index = ItemCache.getindex
+  end
+end
-- 
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