[gnome-builder/wip/elad/jedi-pygobject] python: Add auto-completion support for GObject Introspection imports

[Elad Alfassa <eladalfassa src gnome org>]

commit 13fca7299096fcc2ff9a38c9d619d25a1002e4c9
Author: Elad Alfassa <elad fedoraproject org>
Date:   Fri Jul 24 22:09:27 2015 +0300

    python: Add auto-completion support for GObject Introspection imports
    
    This is a very simple completion provider that completes names of
    importable GObject Introspection enabled libraries when you type
    
    "from gi.repository import"

 configure.ac                                       |    1 +
 plugins/Makefile.am                                |    1 +
 plugins/python-gi-imports-completion/Makefile.am   |   10 ++
 .../python-gi-imports-completion.plugin            |   10 ++
 .../python_gi_imports_completion.py                |  155 ++++++++++++++++++++
 5 files changed, 177 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index a81b5f3..fbd2fde 100644
--- a/configure.ac
+++ b/configure.ac
@@ -403,6 +403,7 @@ AC_CONFIG_FILES([
        plugins/gnome-code-assistance/Makefile
        plugins/html-completion/Makefile
        plugins/jedi/Makefile
+        plugins/python-gi-imports-completion/Makefile
        plugins/mingw/Makefile
        plugins/python-pack/Makefile
        plugins/symbol-tree/Makefile
diff --git a/plugins/Makefile.am b/plugins/Makefile.am
index bf85fba..63f3ff7 100644
--- a/plugins/Makefile.am
+++ b/plugins/Makefile.am
@@ -9,6 +9,7 @@ SUBDIRS = \
        gnome-code-assistance \
        html-completion \
        jedi \
+       python-gi-imports-completion \
        mingw \
        python-pack \
        symbol-tree \
diff --git a/plugins/python-gi-imports-completion/Makefile.am 
b/plugins/python-gi-imports-completion/Makefile.am
new file mode 100644
index 0000000..9c82c49
--- /dev/null
+++ b/plugins/python-gi-imports-completion/Makefile.am
@@ -0,0 +1,10 @@
+EXTRA_DIST = $(plugin_DATA)
+
+plugindir = $(libdir)/gnome-builder/plugins
+plugin_DATA = \
+       python-gi-imports-completion.plugin \
+       python_gi_imports_completion.py
+
+GITIGNOREFILES = __pycache__
+
+-include $(top_srcdir)/git.mk
diff --git a/plugins/python-gi-imports-completion/python-gi-imports-completion.plugin 
b/plugins/python-gi-imports-completion/python-gi-imports-completion.plugin
new file mode 100644
index 0000000..dd47dc9
--- /dev/null
+++ b/plugins/python-gi-imports-completion/python-gi-imports-completion.plugin
@@ -0,0 +1,10 @@
+[Plugin]
+Module=python_gi_imports_completion
+Loader=python3
+Name=Python GObject Introspection Imports Auto-Completion
+Description=Provides autocompletion for importing GObject Introspection enabled Libraries in Python.
+Authors=Christian Hergert <christian hergert me>
+Copyright=Copyright © 2015 Christian Hergert
+Builtin=true
+Hidden=true
+X-Completion-Provider-Languages=python,python3
diff --git a/plugins/python-gi-imports-completion/python_gi_imports_completion.py 
b/plugins/python-gi-imports-completion/python_gi_imports_completion.py
new file mode 100644
index 0000000..8e13d94
--- /dev/null
+++ b/plugins/python-gi-imports-completion/python_gi_imports_completion.py
@@ -0,0 +1,155 @@
+#!/usr/bin/env python3
+
+#
+# python_gi_imports_completion.py
+#
+# Copyright (C) 2015 Christian Hergert <chris dronelabs com>
+# Copyright (C) 2015 Elad Alfassa <elad fedoraproject org>
+#
+# 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, see <http://www.gnu.org/licenses/>.
+#
+
+from gi.repository import GIRepository
+from gi.repository import GLib
+from gi.repository import GObject
+from gi.repository import Gtk
+from gi.repository import GtkSource
+from gi.repository import Ide
+
+import os
+
+
+class CompletionProvider(Ide.Object,
+                         GtkSource.CompletionProvider,
+                         Ide.CompletionProvider):
+    def do_get_name(self):
+        return 'Python GObject Introspection Imports Provider'
+
+    def do_get_icon(self):
+        return None
+
+    def do_populate(self, context):
+
+        _, iter = context.get_iter()
+        buffer = iter.get_buffer()
+
+        # ignore completions if we are following whitespace.
+        copy = iter.copy()
+        copy.set_line_offset(0)
+        text = buffer.get_text(copy, iter, True)
+        if not text or text[-1].isspace():
+            context.add_proposals(self, [], True)
+            return
+        if not text.startswith('from gi.repository import'):
+            context.add_proposals(self, [], True)
+            return
+
+        line = iter.get_line() + 1
+        column = iter.get_line_offset()
+
+        text = text.replace('from gi.repository import', '').strip().lower()
+
+        # TODO: Cache directory contents? watch for changes?
+        proposals = []
+        for directory in GIRepository.Repository.get_search_path():
+            for filename in os.listdir(directory):
+                library_name = filename.split('-')[0]
+                if library_name.lower().startswith(text):
+                    proposals.append(CompletionProposal(self, context,
+                                                        library_name, text))
+        context.add_proposals(self, proposals, True)
+
+    def do_get_activiation(self):
+        return GtkSource.CompletionActivation.INTERACTIVE
+
+    def do_match(self, context):
+        return True
+
+    def do_get_info_widget(self, proposal):
+        return None
+
+    def do_update_info(self, proposal, info):
+        pass
+
+    def do_get_start_iter(self, context, proposal):
+        _, iter = context.get_iter()
+        return True, iter
+
+    def do_activate_proposal(self, provider, proposal):
+        return False, None
+
+    def do_get_interactive_delay(self):
+        return -1
+
+    def do_get_priority(self):
+        return 201
+
+
+class CompletionProposal(GObject.Object, GtkSource.CompletionProposal):
+    def __init__(self, provider, context, completion, start_text, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.provider = provider
+        self.context = context
+        self.completion = completion
+        self.complete = completion[len(start_text):]
+
+    def do_get_label(self):
+        return self.completion
+
+    def do_get_markup(self):
+        return self.completion
+
+    def do_get_text(self):
+        return self.complete
+
+    def do_get_icon(self):
+        return load_icon(self.context, 'lang-include-symbolic')
+
+    def do_hash(self):
+        return hash(self.completion)
+
+    def do_equal(self, other):
+        return False
+
+    def do_changed(self):
+        pass
+
+_icon_cache = {}
+
+
+def purge_cache():
+    _icon_cache.clear()
+
+settings = Gtk.Settings.get_default()
+settings.connect('notify::gtk-theme-name', lambda *_: purge_cache())
+settings.connect('notify::gtk-application-prefer-dark-theme', lambda *_: purge_cache())
+
+
+def load_icon(context, name):
+    if name in _icon_cache:
+        return _icon_cache[name]
+
+    window = context.props.completion.get_info_window()
+    size = 16
+    style_context = window.get_style_context()
+    icon_theme = Gtk.IconTheme.get_default()
+    icon_info = icon_theme.lookup_icon(name, size, 0)
+    if not icon_info:
+        icon = None
+    else:
+        icon = icon_info.load_symbolic_for_context(style_context)
+
+    _icon_cache[name] = icon
+
+    return icon