Add recently-used comparison support (closes bgo#652747)

The recent-files API provided by GTK+ doesn't actually work for Meld
out-of-the-box, because instead of storing individual files, we need to
stored multiple linked files. In other words, we need to store a
comparison, not a file.

This commit adds support for reading and writing a simple comparison
record format with a new Meld-specific mime-type. These files are
stored under the user data directory, and are managed by the new
'recent' module. Meld creates these files for new top-level
comparisons and inserts them into the recently-used store as proxies
for the actual file tuples.

Note that we deliberately avoid recording as recently-used comparisons
that are invoked from other comparisons; a user may open ten quick
file comparisons from a single VC comparison, but they probably don't
actually want to re-open those from the recent files menu.

There is also support for opening comparison files from the command
line. This was added so that recent comparisons can be opened from the
desktop recent files menu, but can also be used to manually open
specified comparisons.

Author: kaiw

Makefile

@@ -12,7 +12,7 @@ SPECIALS := bin/meld meld/paths.py
 BROWSER := firefox
 
 .PHONY:all
-all: $(addsuffix .install,$(SPECIALS)) meld.desktop
+all: $(addsuffix .install,$(SPECIALS)) meld.desktop meld.xml
 	$(MAKE) -C po
 	$(MAKE) -C help
 
@@ -22,6 +22,7 @@ clean:
 		xargs -0 rm -f
 	@find ./bin -type f \( -name '*.install' \) -print0 | xargs -0 rm -f
 	@rm -f data/meld.desktop
+	@rm -f data/mime/meld.xml
 	$(MAKE) -C po clean
 	$(MAKE) -C help clean
 
@@ -60,6 +61,8 @@ install: $(addsuffix .install,$(SPECIALS)) meld.desktop
 		$(DESTDIR)$(libdir_)/meld/paths.py
 	install -m 644 data/meld.desktop \
 		$(DESTDIR)$(sharedir)/applications
+	install -m 644 data/mime/meld.xml \
+		$(DESTDIR)$(sharedir)/mime/packages/
 	$(PYTHON)    -c 'import compileall; compileall.compile_dir("$(DESTDIR)$(libdir_)",10,"$(libdir_)")'
 	$(PYTHON) -O -c 'import compileall; compileall.compile_dir("$(DESTDIR)$(libdir_)",10,"$(libdir_)")'
 	install -m 644 data/gtkrc \
@@ -88,10 +91,14 @@ install: $(addsuffix .install,$(SPECIALS)) meld.desktop
 		$(DESTDIR)$(sharedir)/icons/HighContrast/scalable/apps/meld.svg
 	$(MAKE) -C po install
 	$(MAKE) -C help install
+    update-mime-database $(DESTDIR)$(sharedir)/mime
 
 meld.desktop: data/meld.desktop.in
 	intltool-merge -d po data/meld.desktop.in data/meld.desktop
 
+meld.xml: data/meld.xml.in
+	intltool-merge -d po data/mime/meld.xml.in data/mime/meld.xml
+
 %.install: %
 	$(PYTHON) tools/install_paths \
 		libdir=$(libdir_) \
@@ -109,7 +116,9 @@ uninstall:
 		$(libdir_) \
 		$(bindir)/meld \
 		$(sharedir)/applications/meld.desktop \
+		$(sharedir)/mime/packages/meld.xml \
 		$(sharedir)/pixmaps/meld.png
 	$(MAKE) -C po uninstall
 	$(MAKE) -C help uninstall
+    update-mime-database $(DESTDIR)$(sharedir)/mime
 

data/meld.desktop.in

@@ -7,6 +7,7 @@ Exec=meld %F
 Terminal=false
 Type=Application
 Icon=meld
+MimeType=application/x-meld-comparison
 StartupNotify=true
 Categories=GTK;Development;
 X-GNOME-Bugzilla-Bugzilla=GNOME

data/mime/meld.xml.in

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<mime-info xmlns="http://www.freedesktop.org/standards/shared-mime-info">
+   <mime-type type="application/x-meld-comparison">
+     <comment>Meld comparison description</comment>
+     <glob pattern="*.meldcmp"/>
+     <icon name="meld"/>
+   </mime-type>
+</mime-info>

data/ui/meldapp-ui.xml

@@ -7,6 +7,7 @@
       <separator/>
       <placeholder name="FileActionsPlaceholder" />
       <separator/>
+      <menuitem action="Recent" />
       <menuitem action="Close" />
       <menuitem action="Quit" />
     </menu>

meld/dirdiff.py

@@ -32,6 +32,7 @@
 from . import tree
 from . import misc
 from . import paths
+from . import recent
 from .ui import gnomeglade
 from .ui import emblemcellrenderer
 
@@ -496,6 +497,14 @@ def set_locations(self, locations):
         self.recursively_update( (0,) )
         self._update_diffmaps()
 
+    def get_comparison(self):
+        root = self.model.get_iter_root()
+        if root:
+            folders = self.model.value_paths(root)
+        else:
+            folders = []
+        return recent.TYPE_FOLDER, folders
+
     def recursively_update( self, path ):
         """Recursively update from tree path 'path'.
         """

meld/filediff.py

@@ -40,6 +40,7 @@
 from . import misc
 from . import patchdialog
 from . import paths
+from . import recent
 from . import undo
 from .ui import findbar
 from .ui import gnomeglade
@@ -980,6 +981,10 @@ def set_files(self, files):
         self._connect_buffer_handlers()
         self.scheduler.add_task(self._set_files_internal(files))
 
+    def get_comparison(self):
+        files = [b.data.filename for b in self.textbuffer[:self.num_panes]]
+        return recent.TYPE_FILE, files
+
     def _load_files(self, files, textbuffers):
         self.undosequence.clear()
         yield _("[%s] Set num panes") % self.label_text

meld/filemerge.py

@@ -23,6 +23,7 @@
 from . import filediff
 from . import meldbuffer
 from . import merge
+from . import recent
 
 
 class FileMerge(filediff.FileDiff):
@@ -34,6 +35,10 @@ def _connect_buffer_handlers(self):
         self.textview[0].set_editable(0)
         self.textview[2].set_editable(0)
 
+    def get_comparison(self):
+        comp = filediff.FileDiff.get_comparison(self)
+        return recent.TYPE_MERGE, comp[1]
+
     def _set_files_internal(self, files):
         self.textview[1].set_buffer(meldbuffer.MeldBuffer())
         for i in self._load_files(files, self.textbuffer):

meld/meldapp.py

@@ -21,13 +21,16 @@
 import logging
 import optparse
 import os
+import sys
 from gettext import gettext as _
 
+import gio
 import gobject
 import gtk
 
 from . import filters
 from . import preferences
+from . import recent
 
 version = "1.7.0"
 
@@ -50,6 +53,7 @@ def __init__(self):
                                                 filters.FilterEntry.SHELL)
         self.text_filters = self._parse_filters(self.prefs.regexes,
                                                 filters.FilterEntry.REGEX)
+        self.recent_comparisons = recent.RecentFiles(sys.argv[0])
 
     def create_window(self):
         self.window = meldwindow.MeldWindow()
@@ -115,6 +119,9 @@ def parse_args(self, rawargs):
             help=_("Set the target file for saving a merge result"))
         parser.add_option("--auto-merge", None, action="store_true", default=False,
             help=_("Automatically merge files"))
+        parser.add_option("", "--comparison-file", action="store",
+            type="string", dest="comparison_file", default=None,
+            help=_("Load a saved comparison from a Meld comparison file"))
         parser.add_option("", "--diff", action="callback", callback=self.diff_files_callback,
                           dest="diff", default=[],
                           help=_("Creates a diff tab for up to 3 supplied files or directories."))
@@ -140,7 +147,16 @@ def parse_args(self, rawargs):
         for files in options.diff:
             open_paths(files)
 
-        tab = open_paths(args, options.auto_compare, options.auto_merge)
+        if options.comparison_file:
+            comparison_file_path = os.path.expanduser(options.comparison_file)
+            gio_file = gio.File(path=comparison_file_path)
+            try:
+                tab = self.window.append_recent(gio_file.get_uri())
+            except (IOError, ValueError):
+                parser.error(_("Error reading saved comparison file"))
+        elif args:
+            tab = open_paths(args, options.auto_compare, options.auto_merge)
+
         if options.label and tab:
             tab.set_labels(options.label)
 

meld/melddoc.py

@@ -62,6 +62,10 @@ def __init__(self, prefs):
     def get_info_widgets(self):
         return self.status_info_labels
 
+    def get_comparison(self):
+        """Get the comparison type and path(s) being compared"""
+        pass
+
     def save(self):
         pass
 

meld/meldwindow.py

@@ -29,6 +29,7 @@
 from . import misc
 from . import paths
 from . import preferences
+from . import recent
 from . import task
 from . import vcview
 from .ui import gnomeglade
@@ -89,6 +90,9 @@ def on_response(self, dialog, arg):
             new_tab_idx = self.parentapp.notebook.page_num(new_tab.widget)
             self.parentapp.notebook.set_current_page(new_tab_idx)
 
+            diff_type = recent.COMPARISON_TYPES[page]
+            app.recent_comparisons.add(new_tab)
+
         self.widget.destroy()
 
 
@@ -162,6 +166,15 @@ def __init__(self):
         self.actiongroup.set_translation_domain("meld")
         self.actiongroup.add_actions(actions)
         self.actiongroup.add_toggle_actions(toggleactions)
+
+        recent_action = gtk.RecentAction("Recent",  _("Open Recent"),
+                                         _("Open recent files"), None)
+        recent_action.set_show_private(True)
+        recent_action.set_filter(app.recent_comparisons.recent_filter)
+        recent_action.set_sort_type(gtk.RECENT_SORT_MRU)
+        recent_action.connect("item-activated", self.on_action_recent)
+        self.actiongroup.add_action(recent_action)
+
         self.ui = gtk.UIManager()
         self.ui.insert_action_group(self.actiongroup, 0)
         self.ui.add_ui_from_file(ui_file)
@@ -391,6 +404,16 @@ def on_menu_save_activate(self, menuitem):
     def on_menu_save_as_activate(self, menuitem):
         self.current_doc().save_as()
 
+    def on_action_recent(self, action):
+        uri = action.get_current_uri()
+        if not uri:
+            return
+        try:
+            self.append_recent(uri)
+        except (IOError, ValueError):
+            # FIXME: Need error handling, but no sensible display location
+            pass
+
     def on_menu_close_activate(self, *extra):
         i = self.notebook.get_current_page()
         if i >= 0:
@@ -672,6 +695,19 @@ def append_vcview(self, location, auto_compare=False):
             doc.on_button_diff_clicked(None)
         return doc
 
+    def append_recent(self, uri):
+        comparison_type, files, flags = app.recent_comparisons.read(uri)
+        if comparison_type == recent.TYPE_MERGE:
+            tab = self.append_filemerge(files)
+        elif comparison_type == recent.TYPE_FOLDER:
+            tab = self.append_dirdiff(files)
+        elif comparison_type == recent.TYPE_VC:
+            tab = self.append_vcview(files)
+        else:  # comparison_type == recent.TYPE_FILE:
+            tab = self.append_filediff(files)
+        app.recent_comparisons.add(tab)
+        return tab
+
     def _single_file_open(self, path):
         doc = vcview.VcView(app.prefs)
         def cleanup():
@@ -694,6 +730,7 @@ def open_paths(self, paths, auto_compare=False, auto_merge=False):
 
         elif len(paths) in (2, 3):
             tab = self.append_diff(paths, auto_compare, auto_merge)
+        app.recent_comparisons.add(tab)
         return tab
 
     def current_doc(self):