1 files changed, 55 insertions, 0 deletions
diff --git a/ext/mixed/js/display-context.js b/ext/mixed/js/display-context.js
new file mode 100644
index 00000000..4b399881
--- /dev/null
+++ b/ext/mixed/js/display-context.js
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2019  Alex Yatskov <alex@foosoft.net>
+ * Author: Alex Yatskov <alex@foosoft.net>
+ *
+ * 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/>.
+ */
+
+
+class DisplayContext {
+    constructor(type, definitions, context) {
+        this.type = type;
+        this.definitions = definitions;
+        this.context = context;
+    }
+
+    get(key) {
+        return this.context[key];
+    }
+
+    set(key, value) {
+        this.context[key] = value;
+    }
+
+    update(data) {
+        Object.assign(this.context, data);
+    }
+
+    get previous() {
+        return this.context.previous;
+    }
+
+    get next() {
+        return this.context.next;
+    }
+
+    static push(self, type, definitions, context) {
+        const newContext = new DisplayContext(type, definitions, context);
+        if (self !== null) {
+            newContext.update({previous: self});
+            self.update({next: newContext});
+        }
+        return newContext;
+    }
+}