1 files changed, 48 insertions, 0 deletions
diff --git a/comm/mailnews/base/public/nsIMsgFolderCache.idl b/comm/mailnews/base/public/nsIMsgFolderCache.idl
new file mode 100644
index 0000000000..b5ba40afdc
--- /dev/null
+++ b/comm/mailnews/base/public/nsIMsgFolderCache.idl
@@ -0,0 +1,48 @@
+/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/. */
+
+#include "nsISupports.idl"
+
+interface nsIFile;
+interface nsIMsgFolderCacheElement;
+
+/**
+ * nsIMsgFolderCache is a store of values which might be slow for the folder
+ * to calculate. For example: the number of unread messages.
+ * The account manager holds the cache, and each folder manipulates its cached
+ * properties via nsIMsgFolderCacheElement.
+ */
+[scriptable, uuid(78C2B6A2-E29F-44de-9543-10DBB51E245C)]
+interface nsIMsgFolderCache : nsISupports
+{
+  /**
+   * Set up the cache, loading/saving to cacheFile.
+   * If a new-style cacheFile isn't found, it looks for an old panacea.dat,
+   * specified by legacyFile and migrates it to the new format.
+   * Neither file has to exist - it'll just start up with an empty cache.
+   * nsMsgFolderCache (the only implementation) will autosave to cacheFile
+   * when changes are made.
+   *
+   * @param cacheFile   File to persist the cache data (folderCache.json).
+   * @param legacyFile  Old panacea.dat file to check for and migrate, if
+   *                    cacheFile doesn't exist.
+   */
+  void init(in nsIFile cacheFile, in nsIFile legacyFile);
+
+  /**
+   * Return an nsIMsgFolderCacheElement for a given folder.
+   * Unless createIfMissing is set, a missing entry will cause failure.
+   */
+  nsIMsgFolderCacheElement getCacheElement(in ACString key, in boolean createIfMissing);
+  void removeElement(in ACString key);
+
+  /**
+   * Write immediately to cacheFile if any data has been changed.
+   * Write immediately to cacheFile if any data has been changed.
+   * This happens in the cache dtor anyway, but we use it during shutdown and
+   * in unit testing (so tests don't have to wait for JS garbage collection).
+   */
+  void flush();
+};