[polari/wip/fmuellner/tracker: 46/48] logManager: Add LogWalker for traversing a channel's logs

[Florian Müllner <fmuellner src gnome org>]

commit 1de59f38c75fc63512b79bdbae8d70d204396b8a
Author: Florian Müllner <fmuellner gnome org>
Date:   Fri Jan 8 16:10:17 2016 +0100

    logManager: Add LogWalker for traversing a channel's logs
    
    We still use tp-logger for the history in the chat log. While it works
    well enough in that case, it is odd to use two completely different
    components for log handling, so add our own tracker-based LogWalker
    implementation as a replacement.

 src/logManager.js |   54 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 54 insertions(+), 0 deletions(-)
---
diff --git a/src/logManager.js b/src/logManager.js
index ef2472f..6ceaa2f 100644
--- a/src/logManager.js
+++ b/src/logManager.js
@@ -1,6 +1,7 @@
 const Gio = imports.gi.Gio;
 const Lang = imports.lang;
 const Tracker = imports.gi.Tracker;
+const Tp = imports.gi.TelepathyGLib;
 
 let _logManager = null;
 
@@ -141,6 +142,55 @@ const GenericQuery = new Lang.Class({
     }
 });
 
+const LogWalker = new Lang.Class({
+    Name: 'LogWalker',
+
+    _init: function(connection, room) {
+        this._connection = connection;
+        this._room = room;
+        this._query = null;
+    },
+
+    getEvents: function(numEvents, callback) {
+        if (!this._query) {
+            this._query = new GenericQuery(this._connection, numEvents);
+
+            let roomFilter;
+            if (this._room.type == Tp.HandleType.ROOM)
+                roomFilter = '  filter (nie:title (?chan) = "%s") ';
+            else
+                roomFilter = '?chan nmo:hasParticipant ?participant .' +
+                             '?participant fts:match "%s"';
+
+            let sparql = (
+                'select nie:plainTextContent(?msg) as ?message ' +
+                '       if (nmo:from(?msg) = nco:default-contact-me,' +
+                '           "%s", nco:nickname(nmo:from(?msg))) as ?sender ' +
+                // FIXME: how do we handle the "real" message type?
+                '       %d as ?messageType ' +
+                '       ?timestamp ' +
+                '{ ?msg a nmo:IMMessage; ' +
+                '       nie:contentCreated ?timestamp; ' +
+                '       nmo:communicationChannel ?chan . ' +
+                // FIXME: filter by account
+                roomFilter +
+                '}'
+            ).format(this._room.account.nickname,
+                     Tp.ChannelTextMessageType.NORMAL,
+                     this._room.channel_name);
+            this._query.run(sparql, null, r => callback(r.reverse()))
+        } else {
+            this._query.next(numEvents, null, r => callback(r.reverse()));
+        }
+    },
+
+    isEnd: function() {
+        if (this._query)
+            return this._query.isClosed();
+        return false;
+    }
+});
+
 const _LogManager = new Lang.Class({
     Name: 'LogManager',
 
@@ -151,5 +201,9 @@ const _LogManager = new Lang.Class({
     query: function(sparql, cancellable, callback) {
         let query = new GenericQuery(this._connection);
         query.run(sparql, cancellable, callback);
+     },
+
+     walkEvents: function(room) {
+         return new LogWalker(this._connection, room);
      }
 });