refactoring th code for page handling

1 files changed, 221 insertions, 0 deletions

diff --git a/model_history.py b/model_history.py
new file mode 100644
index 0000000..8ca1e08
--- /dev/null
+++ b/model_history.py
@@ -0,0 +1,221 @@
+# coding: UTF-8
+# Copyright 2009, 2010 Thomas Jourdan
+#
+# 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 3 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+class KandidHistory(object):
+    """
+    """
+    _history = None
+    _icon_width = 48
+    _newest = 1
+
+    class Item(object):
+        def __init__(self, init_parent1_id, init_parent2_id):
+            self.ref_count = 0
+            self.surface = None
+            self.parent1_id = init_parent1_id
+            self.parent2_id = init_parent2_id
+            self.old = 0
+
+        def __str__(self):
+            return '(' \
+                + str(self.ref_count) + ', ' \
+                + (self.parent1_id if self.parent1_id is not None else 'None') \
+                + ', ' \
+                + (self.parent2_id if self.parent2_id is not None else 'None') \
+                + ', ' \
+                + (str(self.surface) if self.surface is not None else 'None') \
+                + ')'
+
+    def __init__(self):
+        """
+        inv: self.parents is not None
+        """
+        self.parents = {}
+        self.assumed_icon_width = KandidHistory._icon_width
+        self.surfaces_referenced = 0
+ 
+    @staticmethod
+    def instance():
+        if KandidHistory._history is None:
+            KandidHistory._history = KandidHistory()
+        return KandidHistory._history
+    
+    def clear(self):
+        self.parents = {}
+        self.surfaces_referenced = 0
+
+    def rember_parents(self, my_id, parent1_id, parent2_id):
+        """Remember the ids of my parents.
+        pre: my_id is not None and my_id.startswith('_')
+        pre: parent1_id is not None and parent1_id.startswith('_')
+        pre: parent2_id is not None and parent2_id.startswith('_')
+        pre: not my_id == parent1_id
+        pre: not my_id == parent2_id
+        """
+        if my_id not in self.parents:
+            self.parents[my_id] = KandidHistory.Item(parent1_id, parent2_id)
+        else:
+            self.parents[my_id].parent1_id = parent1_id
+            self.parents[my_id].parent2_id = parent2_id
+        if parent1_id in self.parents:
+            self.parents[parent1_id].ref_count += 1
+        if parent2_id in self.parents:
+            self.parents[parent2_id].ref_count += 1
+
+    def link_surface(self, my_id, my_surface):
+        """Link an id with an surface
+        pre: my_id is not None and my_id.startswith('_')
+        pre: my_surface is not None
+        """
+        if my_id not in self.parents:
+            self.parents[my_id] = KandidHistory.Item(None, None)
+#!!            self.parents[my_id].ref_count += -1
+        if self.parents[my_id].surface is None:
+            self.surfaces_referenced += 1
+        self.parents[my_id].surface = my_surface
+        self.parents[my_id].old = KandidHistory._newest
+        KandidHistory._newest += 1
+        self._limit_memory_usage()
+        
+    def _limit_memory_usage(self):
+        """
+        limit memory usage, forget old surfaces
+        """
+        while self.surfaces_referenced > 25:
+            min_id, min_old = None, 2**31
+            for key, parent in self.parents.iteritems():
+                if parent.surface is not None and parent.old < min_old:
+                    min_id, min_old  = key, parent.old
+            if min_id is not None:
+                self.parents[min_id].surface = None
+                self.surfaces_referenced -= 1
+                          
+    def unlink(self, my_id):
+        """Forget an id and free the linked surface.
+        pre: my_id is not None and my_id.startswith('_')
+        """
+        if my_id in self.parents:
+            self.parents[my_id].ref_count -= 1
+            if self.parents[my_id].ref_count < 0:
+                my_parents = self.get_parents(my_id)
+                parent1_id, parent2_id = my_parents[0], my_parents[1]
+                if parent1_id in self.parents:
+                    self.unlink(parent1_id)
+                if parent2_id in self.parents:
+                    self.unlink(parent2_id)
+                if self.parents[my_id].surface is not None:
+                    self.surfaces_referenced -= 1
+                del self.parents[my_id]
+
+    def contains(self, my_id):
+        """Returns True if my_id can be found.
+        pre: my_id is not None and my_id.startswith('_')
+        """
+        return my_id in self.parents
+
+    def get_parents(self, my_id):
+        """Return ids of both parents
+        pre: my_id is not None and my_id.startswith('_')
+        pre: self.parents.has_key(my_id)
+        post: len(__return__) == 2
+        """
+        my_parents = self.parents[my_id]
+        return ( my_parents.parent1_id, my_parents.parent2_id )
+
+    def get_surface(self, my_id):
+        """
+        pre: my_id is not None and my_id.startswith('_')
+        """
+        return self.parents[my_id].surface if my_id in self.parents else None
+
+#    def get_pixbuf(self, my_id):
+#        """
+#        pre: my_id is not None and my_id.startswith('_')
+#        """
+#        pixbuf, surface = None, self.get_surface(my_id)
+#        if surface is not None:
+#            width, height = surface.get_width(), surface.get_height()
+#            pixmap = gtk.gdk.Pixmap (None, width, height, 24)
+#            cr = pixmap.cairo_create()
+#            cr.set_source_surface(surface, 0, 0)
+#            cr.paint()
+#            pixbuf = gtk.gdk.Pixbuf(gtk.gdk.COLORSPACE_RGB, True, 8, width, height)
+#            pixbuf = pixbuf.get_from_drawable(pixmap, gtk.gdk.colormap_get_system(), 0, 0, 0, 0, width, height)
+#        return pixbuf
+
+#    def get_pixbuf(self, my_id):
+#        """
+#        pre: my_id is not None and my_id.startswith('_')
+#        """
+#        pixbuf, surface = None, self.get_surface(my_id)
+#        if surface is not None:
+#            filename = '/dev/shm/' + my_id + '.png'
+#            surface.write_to_png(filename)
+#            pixbuf = gtk.gdk.pixbuf_new_from_file(filename)
+#        return pixbuf
+
+#    def get_treestore(self, my_id):
+#        """
+#        pre: my_id is not None and my_id.startswith('_')
+#        """
+#        treestore = gtk.TreeStore(gtk.gdk.Pixbuf, str)
+#        self.assumed_icon_width, icon = self._draw_icon(my_id)
+#        it = treestore.append(None, [icon, my_id])
+#        self._get_treestore0(my_id, treestore, it)
+#        return treestore
+#
+#    def _get_treestore0(self, my_id, treestore, it):
+#        """
+#        pre: my_id is not None and my_id.startswith('_')
+#        pre: treestore is not None
+#        pre: it is not None
+#        """
+#        if my_id is not None and self.contains(my_id): 
+#            my_parents = self.get_parents(my_id)
+#            parent1_id, parent2_id = my_parents[0], my_parents[1]
+#            self._append_node(my_id, parent1_id, treestore, it)
+#            self._append_node(my_id, parent2_id, treestore, it)
+#
+#    def _append_node(self, my_id, parent_id, treestore, it):
+#        if parent_id is not None:
+#            title = parent_id if self.parents[my_id].surface is not None \
+#                        else parent_id + _('Sorry, can not remember the image')
+#            child_it = treestore.append(it, [self._draw_icon(parent_id)[1],
+#                                             title])
+#            self._get_treestore0(parent_id, treestore, child_it)
+#
+#    def _draw_icon(self, my_id):
+#        """
+#        post: len(__return__) == 2
+#        post: __return__[0] >= 0
+#        """
+#        pixbuf = None
+#        width = KandidHistory._icon_width
+#        if my_id in self.parents:
+#            surface = self.parents[my_id].surface
+#            if surface is not None:
+#                width, h = surface.get_width(), surface.get_height()
+#                pixmap = gtk.gdk.Pixmap (None, width, h, 24)
+#                cr = pixmap.cairo_create()
+#                cr.set_source_surface(surface, 0, 0)
+#                cr.paint()
+#                pixbuf = gtk.gdk.Pixbuf(gtk.gdk.COLORSPACE_RGB, True, 8, width, h)
+#                pixbuf = pixbuf.get_from_drawable(pixmap, gtk.gdk.colormap_get_system(), 0, 0, 0, 0, width, h)
+#        if pixbuf is None:
+#            theme = gtk.icon_theme_get_default()
+#            pixbuf = theme.load_icon(gtk.STOCK_DELETE, KandidHistory._icon_width, 0)
+#        return width, pixbuf