1 files changed, 84 insertions, 0 deletions
diff --git a/comm/mail/modules/FolderTreeProperties.jsm b/comm/mail/modules/FolderTreeProperties.jsm
new file mode 100644
index 0000000000..6931c2794a
--- /dev/null
+++ b/comm/mail/modules/FolderTreeProperties.jsm
@@ -0,0 +1,84 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Persistent storage for various properties of items on the folder tree.
+ * Data is serialised to the file folderTree.json in the profile directory.
+ */
+
+const EXPORTED_SYMBOLS = ["FolderTreeProperties"];
+
+const { JSONFile } = ChromeUtils.importESModule(
+  "resource://gre/modules/JSONFile.sys.mjs"
+);
+
+var jsonFile = new JSONFile({
+  path: PathUtils.join(PathUtils.profileDir, "folderTree.json"),
+});
+var readyPromise = jsonFile.load();
+
+function ensureReady() {
+  if (!jsonFile.dataReady) {
+    throw new Error("Folder tree properties cache not ready.");
+  }
+}
+
+var FolderTreeProperties = {
+  get ready() {
+    return readyPromise;
+  },
+
+  /**
+   * Get the colour associated with a folder.
+   *
+   * @param {string} folderURI
+   * @returns {?string}
+   */
+  getColor(folderURI) {
+    ensureReady();
+    return jsonFile.data.colors?.[folderURI];
+  },
+
+  /**
+   * Set the colour associated with a folder.
+   *
+   * @param {string} folderURI
+   * @param {string} color
+   */
+  setColor(folderURI, color) {
+    ensureReady();
+    jsonFile.data.colors = jsonFile.data.colors ?? {};
+    jsonFile.data.colors[folderURI] = color;
+    jsonFile.saveSoon();
+  },
+
+  resetColors() {
+    ensureReady();
+    delete jsonFile.data.colors;
+    jsonFile.saveSoon();
+  },
+
+  getIsExpanded(folderURI, mode) {
+    ensureReady();
+    if (!Array.isArray(jsonFile.data.open?.[mode])) {
+      return false;
+    }
+    return jsonFile.data.open[mode].includes(folderURI);
+  },
+
+  setIsExpanded(folderURI, mode, isExpanded) {
+    ensureReady();
+    jsonFile.data.open = jsonFile.data.open ?? {};
+    jsonFile.data.open[mode] = jsonFile.data.open[mode] ?? [];
+    let index = jsonFile.data.open[mode].indexOf(folderURI);
+    if (isExpanded) {
+      if (index < 0) {
+        jsonFile.data.open[mode].push(folderURI);
+      }
+    } else if (index >= 0) {
+      jsonFile.data.open[mode].splice(index, 1);
+    }
+    jsonFile.saveSoon();
+  },
+};