diff -r 058bb3dc685f -r 0b59724cb3f2 cubicweb/web/views/navigation.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cubicweb/web/views/navigation.py	Sat Jan 16 13:48:51 2016 +0100
@@ -0,0 +1,415 @@
+# copyright 2003-2011 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
+# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
+#
+# This file is part of CubicWeb.
+#
+# CubicWeb is free software: you can redistribute it and/or modify it under the
+# terms of the GNU Lesser General Public License as published by the Free
+# Software Foundation, either version 2.1 of the License, or (at your option)
+# any later version.
+#
+# CubicWeb 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 Lesser General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Lesser General Public License along
+# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.
+"""This module provides some generic components to navigate in the web
+application.
+
+Pagination
+----------
+
+Several implementations for large result set pagination are provided:
+
+.. autoclass:: PageNavigation
+.. autoclass:: PageNavigationSelect
+.. autoclass:: SortedNavigation
+
+Pagination will appear when needed according to the `page-size` ui property.
+
+This module monkey-patch the :func:`paginate` function to the base :class:`View`
+class, so that you can ask pagination explicitly on every result-set based views.
+
+.. autofunction:: paginate
+
+
+Previous / next navigation
+--------------------------
+
+An adapter and its related component for the somewhat usal "previous / next"
+navigation are provided.
+
+  .. autoclass:: IPrevNextAdapter
+  .. autoclass:: NextPrevNavigationComponent
+"""
+
+__docformat__ = "restructuredtext en"
+from cubicweb import _
+
+from datetime import datetime
+
+from six import text_type
+
+from rql.nodes import VariableRef, Constant
+
+from logilab.mtconverter import xml_escape
+from logilab.common.deprecation import deprecated
+
+from cubicweb.predicates import paginated_rset, sorted_rset, adaptable
+from cubicweb.uilib import cut
+from cubicweb.view import EntityAdapter
+from cubicweb.web.component import EmptyComponent, EntityCtxComponent, NavigationComponent
+
+
+class PageNavigation(NavigationComponent):
+    """The default pagination component: display link to pages where each pages
+    is identified by the item number of its first and last elements.
+    """
+    def call(self):
+        """displays a resultset by page"""
+        params = dict(self._cw.form)
+        self.clean_params(params)
+        basepath = self._cw.relative_path(includeparams=False)
+        self.w(u'<div class="pagination">')
+        self.w(self.previous_link(basepath, params))
+        self.w(u'[&#160;%s&#160;]' %
+               u'&#160;| '.join(self.iter_page_links(basepath, params)))
+        self.w(u'&#160;&#160;%s' % self.next_link(basepath, params))
+        self.w(u'</div>')
+
+    def index_display(self, start, stop):
+        return u'%s - %s' % (start+1, stop+1)
+
+    def iter_page_links(self, basepath, params):
+        rset = self.cw_rset
+        page_size = self.page_size
+        start = 0
+        while start < rset.rowcount:
+            stop = min(start + page_size - 1, rset.rowcount - 1)
+            yield self.page_link(basepath, params, start, stop,
+                                 self.index_display(start, stop))
+            start = stop + 1
+
+
+class PageNavigationSelect(PageNavigation):
+    """This pagination component displays a result-set by page as
+    :class:`PageNavigation` but in a <select>, which is better when there are a
+    lot of results.
+
+    By default it will be selected when there are more than 4 pages to be
+    displayed.
+    """
+    __select__ = paginated_rset(4)
+
+    page_link_templ = u'<option value="%s" title="%s">%s</option>'
+    selected_page_link_templ = u'<option value="%s" selected="selected" title="%s">%s</option>'
+    def call(self):
+        params = dict(self._cw.form)
+        self.clean_params(params)
+        basepath = self._cw.relative_path(includeparams=False)
+        w = self.w
+        w(u'<div class="pagination">')
+        w(self.previous_link(basepath, params))
+        w(u'<select onchange="javascript: document.location=this.options[this.selectedIndex].value">')
+        for option in self.iter_page_links(basepath, params):
+            w(option)
+        w(u'</select>')
+        w(u'&#160;&#160;%s' % self.next_link(basepath, params))
+        w(u'</div>')
+
+
+class SortedNavigation(NavigationComponent):
+    """This pagination component will be selected by default if there are less
+    than 4 pages and if the result set is sorted.
+
+    Displayed links to navigate accross pages of a result set are done according
+    to the first variable on which the sort is done, and looks like:
+
+        [ana - cro] | [cro - ghe] | ... | [tim - zou]
+
+    You may want to override this component to customize display in some cases.
+
+    .. automethod:: sort_on
+    .. automethod:: display_func
+    .. automethod:: format_link_content
+    .. automethod:: write_links
+
+    Below an example from the tracker cube:
+
+    .. sourcecode:: python
+
+      class TicketsNavigation(navigation.SortedNavigation):
+          __select__ = (navigation.SortedNavigation.__select__
+                        & ~paginated_rset(4) & is_instance('Ticket'))
+          def sort_on(self):
+              col, attrname = super(TicketsNavigation, self).sort_on()
+              if col == 6:
+                  # sort on state, we don't want that
+                  return None, None
+              return col, attrname
+
+    The idea is that in trackers'ticket tables, result set is first ordered on
+    ticket's state while this doesn't make any sense in the navigation. So we
+    override :meth:`sort_on` so that if we detect such sorting, we disable the
+    feature to go back to item number in the pagination.
+
+    Also notice the `~paginated_rset(4)` in the selector so that if there are
+    more than 4 pages to display, :class:`PageNavigationSelect` will still be
+    selected.
+    """
+    __select__ = paginated_rset() & sorted_rset()
+
+    # number of considered chars to build page links
+    nb_chars = 5
+
+    def call(self):
+        # attrname = the name of attribute according to which the sort
+        # is done if any
+        col, attrname = self.sort_on()
+        index_display = self.display_func(self.cw_rset, col, attrname)
+        basepath = self._cw.relative_path(includeparams=False)
+        params = dict(self._cw.form)
+        self.clean_params(params)
+        blocklist = []
+        start = 0
+        total = self.cw_rset.rowcount
+        while start < total:
+            stop = min(start + self.page_size - 1, total - 1)
+            cell = self.format_link_content(index_display(start), index_display(stop))
+            blocklist.append(self.page_link(basepath, params, start, stop, cell))
+            start = stop + 1
+        self.write_links(basepath, params, blocklist)
+
+    def display_func(self, rset, col, attrname):
+        """Return a function that will be called with a row number as argument
+        and should return a string to use as link for it.
+        """
+        if attrname is not None:
+            def index_display(row):
+                if not rset[row][col]: # outer join
+                    return u''
+                entity = rset.get_entity(row, col)
+                return entity.printable_value(attrname, format='text/plain')
+        elif col is None: # smart links disabled.
+            def index_display(row):
+                return text_type(row)
+        elif self._cw.vreg.schema.eschema(rset.description[0][col]).final:
+            def index_display(row):
+                return text_type(rset[row][col])
+        else:
+            def index_display(row):
+                return rset.get_entity(row, col).view('text')
+        return index_display
+
+    def sort_on(self):
+        """Return entity column number / attr name to use for nice display by
+        inspecting the rset'syntax tree.
+        """
+        rschema = self._cw.vreg.schema.rschema
+        for sorterm in self.cw_rset.syntax_tree().children[0].orderby:
+            if isinstance(sorterm.term, Constant):
+                col = sorterm.term.value - 1
+                return col, None
+            var = sorterm.term.get_nodes(VariableRef)[0].variable
+            col = None
+            for ref in var.references():
+                rel = ref.relation()
+                if rel is None:
+                    continue
+                attrname = rel.r_type
+                if attrname in ('is', 'has_text'):
+                    continue
+                if not rschema(attrname).final:
+                    col = var.selected_index()
+                    attrname = None
+                if col is None:
+                    # final relation or not selected non final relation
+                    if var is rel.children[0]:
+                        relvar = rel.children[1].children[0].get_nodes(VariableRef)[0]
+                    else:
+                        relvar = rel.children[0].variable
+                    col = relvar.selected_index()
+                if col is not None:
+                    break
+            else:
+                # no relation but maybe usable anyway if selected
+                col = var.selected_index()
+                attrname = None
+            if col is not None:
+                # if column type is date[time], set proper 'nb_chars'
+                if var.stinfo['possibletypes'] & frozenset(('TZDatetime', 'Datetime',
+                                                            'Date')):
+                    self.nb_chars = len(self._cw.format_date(datetime.today()))
+                return col, attrname
+        # nothing usable found, use the first column
+        return 0, None
+
+    def format_link_content(self, startstr, stopstr):
+        """Return text for a page link, where `startstr` and `stopstr` are the
+        text for the lower/upper boundaries of the page.
+
+        By default text are stripped down to :attr:`nb_chars` characters.
+        """
+        text = u'%s - %s' % (startstr.lower()[:self.nb_chars],
+                             stopstr.lower()[:self.nb_chars])
+        return xml_escape(text)
+
+    def write_links(self, basepath, params, blocklist):
+        """Return HTML for the whole navigation: `blocklist` is a list of HTML
+        snippets for each page, `basepath` and `params` will be necessary to
+        build previous/next links.
+        """
+        self.w(u'<div class="pagination">')
+        self.w(u'%s&#160;' % self.previous_link(basepath, params))
+        self.w(u'[&#160;%s&#160;]' % u'&#160;| '.join(blocklist))
+        self.w(u'&#160;%s' % self.next_link(basepath, params))
+        self.w(u'</div>')
+
+
+def do_paginate(view, rset=None, w=None, show_all_option=True, page_size=None):
+    """write pages index in w stream (default to view.w) and then limit the
+    result set (default to view.rset) to the currently displayed page if we're
+    not explicitly told to display everything (by setting __force_display in
+    req.form)
+    """
+    req = view._cw
+    if rset is None:
+        rset = view.cw_rset
+    if w is None:
+        w = view.w
+    nav = req.vreg['components'].select_or_none(
+        'navigation', req, rset=rset, page_size=page_size, view=view)
+    if nav:
+        if w is None:
+            w = view.w
+        if req.form.get('__force_display'):
+            # allow to come back to the paginated view
+            params = dict(req.form)
+            basepath = req.relative_path(includeparams=False)
+            del params['__force_display']
+            url = nav.page_url(basepath, params)
+            w(u'<div class="displayAllLink"><a href="%s">%s</a></div>\n'
+              % (xml_escape(url), req._('back to pagination (%s results)')
+                                  % nav.page_size))
+        else:
+            # get boundaries before component rendering
+            start, stop = nav.page_boundaries()
+            nav.render(w=w)
+            params = dict(req.form)
+            nav.clean_params(params)
+            # make a link to see them all
+            if show_all_option:
+                basepath = req.relative_path(includeparams=False)
+                params['__force_display'] = 1
+                params['__fromnavigation'] = 1
+                url = nav.page_url(basepath, params)
+                w(u'<div class="displayAllLink"><a href="%s">%s</a></div>\n'
+                  % (xml_escape(url), req._('show %s results') % len(rset)))
+            rset.limit(offset=start, limit=stop-start, inplace=True)
+
+
+def paginate(view, show_all_option=True, w=None, page_size=None, rset=None):
+    """paginate results if the view is paginable
+    """
+    if view.paginable:
+        do_paginate(view, rset, w, show_all_option, page_size)
+
+# monkey patch base View class to add a .paginate([...])
+# method to be called to write pages index in the view and then limit the result
+# set to the current page
+from cubicweb.view import View
+View.do_paginate = do_paginate
+View.paginate = paginate
+View.handle_pagination = False
+
+
+
+class IPrevNextAdapter(EntityAdapter):
+    """Interface for entities which can be linked to a previous and/or next
+    entity
+
+    .. automethod:: next_entity
+    .. automethod:: previous_entity
+    """
+    __needs_bw_compat__ = True
+    __regid__ = 'IPrevNext'
+    __abstract__ = True
+
+    def next_entity(self):
+        """return the 'next' entity"""
+        raise NotImplementedError
+
+    def previous_entity(self):
+        """return the 'previous' entity"""
+        raise NotImplementedError
+
+
+class NextPrevNavigationComponent(EntityCtxComponent):
+    """Entities adaptable to the 'IPrevNext' should have this component
+    automatically displayed. You may want to override this component to have a
+    different look and feel.
+    """
+
+    __regid__ = 'prevnext'
+    # register msg not generated since no entity implements IPrevNext in cubicweb
+    # itself
+    help = _('ctxcomponents_prevnext_description')
+    __select__ = EntityCtxComponent.__select__ & adaptable('IPrevNext')
+    context = 'navbottom'
+    order = 10
+
+    @property
+    def prev_icon(self):
+        return '<img src="%s" alt="%s" />' % (
+            xml_escape(self._cw.data_url('go_prev.png')), self._cw._('previous page'))
+
+    @property
+    def next_icon(self):
+        return '<img src="%s" alt="%s" />' % (
+            xml_escape(self._cw.data_url('go_next.png')), self._cw._('next page'))
+
+    def init_rendering(self):
+        adapter = self.entity.cw_adapt_to('IPrevNext')
+        self.previous = adapter.previous_entity()
+        self.next = adapter.next_entity()
+        if not (self.previous or self.next):
+            raise EmptyComponent()
+
+    def render_body(self, w):
+        w(u'<div class="prevnext">')
+        self.prevnext(w)
+        w(u'</div>')
+        w(u'<div class="clear"></div>')
+
+    def prevnext(self, w):
+        if self.previous:
+            self.prevnext_entity(w, self.previous, 'prev')
+        if self.next:
+            self.prevnext_entity(w, self.next, 'next')
+
+    def prevnext_entity(self, w, entity, type):
+        textsize = self._cw.property_value('navigation.short-line-size')
+        content = xml_escape(cut(entity.dc_title(), textsize))
+        if type == 'prev':
+            title = self._cw._('i18nprevnext_previous')
+            icon = self.prev_icon
+            cssclass = u'previousEntity left'
+            content = icon + '&#160;&#160;' + content
+        else:
+            title = self._cw._('i18nprevnext_next')
+            icon = self.next_icon
+            cssclass = u'nextEntity right'
+            content = content + '&#160;&#160;' + icon
+        self.prevnext_div(w, type, cssclass, entity.absolute_url(),
+                          title, content)
+
+    def prevnext_div(self, w, type, cssclass, url, title, content):
+        w(u'<div class="%s">' % cssclass)
+        w(u'<a href="%s" title="%s">%s</a>' % (xml_escape(url),
+                                               xml_escape(title),
+                                               content))
+        w(u'</div>')
+        self._cw.html_headers.add_raw('<link rel="%s" href="%s" />' % (
+              type, xml_escape(url)))