[polari/wip/fmuellner/tracker: 14/18] logManager: Add convenience wrapper for tracker queries

[Florian Müllner <fmuellner src gnome org>]

commit 508ad120640a56a4e0c68f7a2f65aaba3fbcf1fb
Author: Florian Müllner <fmuellner gnome org>
Date:   Thu Dec 24 05:02:35 2015 +0100

    logManager: Add convenience wrapper for tracker queries
    
    As telepathy-logger is unsuitable for anything more advanced than
    retrieving logs sequentially (at least with acceptable performance),
    we want to replace it with tracker eventually. To prepare for that,
    add our own LogManager singleton that wraps a tracker connection and
    provides a convenient API to get result objects from a SPARQL query.

 src/logManager.js                      |  123 ++++++++++++++++++++++++++++++++
 src/org.gnome.Polari.src.gresource.xml |    1 +
 2 files changed, 124 insertions(+), 0 deletions(-)
---
diff --git a/src/logManager.js b/src/logManager.js
new file mode 100644
index 0000000..396255c
--- /dev/null
+++ b/src/logManager.js
@@ -0,0 +1,123 @@
+const Gio = imports.gi.Gio;
+const Lang = imports.lang;
+const Tracker = imports.gi.Tracker;
+
+let _logManager = null;
+
+function getDefault() {
+    if (!_logManager)
+        _logManager = new _LogManager();
+    return _logManager;
+}
+
+const GenericQuery = new Lang.Class({
+    Name: 'GenericQuery',
+
+    _init: function(connection) {
+        this._connection = connection;
+        this._results = [];
+        this._task = null;
+    },
+
+    run: function(sparql, cancellable, callback) {
+        this._task = Gio.Task.new(this._connection, cancellable, Lang.bind(this,
+            function(o, res) {
+                let success = false;
+                try {
+                    success = this._task.propagate_boolean();
+                } catch(e) {
+                    log("Failed to run query: "  + e.message);
+                }
+
+                callback(success ? this._results : []);
+                this._task = null;
+            }));
+
+        this._connection.query_async(sparql, cancellable, Lang.bind(this,
+            function(c, res) {
+                let cursor;
+                try {
+                    cursor = this._connection.query_finish(res);
+                } catch(e) {
+                    this._task.return_error(e);
+                    return;
+                }
+
+                cursor.next_async(cancellable,
+                                  Lang.bind(this, this._onCursorNext));
+            }));
+    },
+
+    _onCursorNext: function(cursor, res) {
+        let valid = false;
+        try {
+            valid = cursor.next_finish(res);
+        } catch(e) {
+            this._task.return_error(e);
+        }
+
+        if (valid) {
+            this._pushResult(cursor);
+            cursor.next_async(this._task.get_cancellable(),
+                              Lang.bind(this, this._onCursorNext));
+        } else {
+            cursor.close();
+            if (!this._task.had_error())
+                this._task.return_boolean(true);
+        }
+    },
+
+    _getColumnsValue: function(cursor, col) {
+        switch(cursor.get_value_type(col)) {
+            case Tracker.SparqlValueType.STRING:
+                return cursor.get_string(col)[0];
+            case Tracker.SparqlValueType.INTEGER:
+                return cursor.get_integer(col);
+            case Tracker.SparqlValueType.DOUBLE:
+                return cursor.get_double(col);
+            case Tracker.SparqlValueType.BOOLEAN:
+                return cursor.get_boolean(col);
+            case Tracker.SparqlValueType.DATETIME:
+                return Date.parse(cursor.get_string(col)[0]) / 1000;
+            case Tracker.SparqlValueType.BLANK_NODE:
+            case Tracker.SparqlValueType.UNBOUND:
+                return null;
+            default:
+                throw new Error("Unhandled result type");
+        }
+    },
+
+    _getValue: function(cursor) {
+        let nCols = cursor.get_n_columns();
+        if (nCols == 1)
+            return this._getColumnsValue(cursor, 0);
+
+        let value = {};
+        for (let i = 0; i < nCols; i++) {
+            let name = cursor.get_variable_name(i);
+            value[name] = this._getColumnsValue(cursor, i);
+        }
+        return value;
+    },
+
+    _pushResult: function(cursor) {
+        try {
+            this._results.push(this._getValue(cursor));
+        } catch(e) {
+            log("Error fetching result: " + e.toString());
+        }
+    }
+});
+
+const _LogManager = new Lang.Class({
+    Name: 'LogManager',
+
+    _init: function() {
+        this._connection = Tracker.SparqlConnection.get(null);
+    },
+
+    query: function(sparql, cancellable, callback) {
+        let query = new GenericQuery(this._connection);
+        query.run(sparql, cancellable, callback);
+     }
+});
diff --git a/src/org.gnome.Polari.src.gresource.xml b/src/org.gnome.Polari.src.gresource.xml
index a526f25..545c926 100644
--- a/src/org.gnome.Polari.src.gresource.xml
+++ b/src/org.gnome.Polari.src.gresource.xml
@@ -9,6 +9,7 @@
     <file>entryArea.js</file>
     <file>ircParser.js</file>
     <file>joinDialog.js</file>
+    <file>logManager.js</file>
     <file>main.js</file>
     <file>mainWindow.js</file>
     <file>networksManager.js</file>