1 files changed, 114 insertions, 0 deletions
diff --git a/js/misc/history.js b/js/misc/history.js
new file mode 100644
index 0000000..268f13b
--- /dev/null
+++ b/js/misc/history.js
@@ -0,0 +1,114 @@
+// -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
+/* exported HistoryManager */
+
+const Signals = imports.misc.signals;
+const Clutter = imports.gi.Clutter;
+const Params = imports.misc.params;
+
+var DEFAULT_LIMIT = 512;
+
+var HistoryManager = class extends Signals.EventEmitter {
+    constructor(params) {
+        super();
+
+        params = Params.parse(params, {
+            gsettingsKey: null,
+            limit: DEFAULT_LIMIT,
+            entry: null,
+        });
+
+        this._key = params.gsettingsKey;
+        this._limit = params.limit;
+
+        this._historyIndex = 0;
+        if (this._key) {
+            this._history = global.settings.get_strv(this._key);
+            global.settings.connect(`changed::${this._key}`,
+                                    this._historyChanged.bind(this));
+        } else {
+            this._history = [];
+        }
+
+        this._entry = params.entry;
+
+        if (this._entry) {
+            this._entry.connect('key-press-event',
+                                this._onEntryKeyPress.bind(this));
+        }
+    }
+
+    _historyChanged() {
+        this._history = global.settings.get_strv(this._key);
+        this._historyIndex = this._history.length;
+    }
+
+    _setPrevItem(text) {
+        if (this._historyIndex <= 0)
+            return false;
+
+        if (text)
+            this._history[this._historyIndex] = text;
+        this._historyIndex--;
+        this._indexChanged();
+        return true;
+    }
+
+    _setNextItem(text) {
+        if (this._historyIndex >= this._history.length)
+            return false;
+
+        if (text)
+            this._history[this._historyIndex] = text;
+        this._historyIndex++;
+        this._indexChanged();
+        return true;
+    }
+
+    lastItem() {
+        if (this._historyIndex !== this._history.length) {
+            this._historyIndex = this._history.length;
+            this._indexChanged();
+        }
+
+        return this._historyIndex ? this._history[this._historyIndex - 1] : null;
+    }
+
+    addItem(input) {
+        input = input.trim();
+        if (input &&
+            (this._history.length === 0 ||
+             this._history[this._history.length - 1] !== input)) {
+            this._history = this._history.filter(entry => entry !== input);
+            this._history.push(input);
+            this._save();
+        }
+        this._historyIndex = this._history.length;
+        return input; // trimmed
+    }
+
+    _onEntryKeyPress(entry, event) {
+        let symbol = event.get_key_symbol();
+        if (symbol === Clutter.KEY_Up)
+            return this._setPrevItem(entry.get_text().trim());
+        else if (symbol === Clutter.KEY_Down)
+            return this._setNextItem(entry.get_text().trim());
+
+        return Clutter.EVENT_PROPAGATE;
+    }
+
+    _indexChanged() {
+        let current = this._history[this._historyIndex] || '';
+        this.emit('changed', current);
+
+        if (this._entry)
+            this._entry.set_text(current);
+    }
+
+    _save() {
+        if (this._history.length > this._limit)
+            this._history.splice(0, this._history.length - this._limit);
+
+        if (this._key)
+            global.settings.set_strv(this._key, this._history);
+    }
+};