queue blob and channel deletions per-user

lib/commands/channel.js

@@ -54,16 +54,8 @@ Channel.clearOwnedChannel = function (Env, safeKey, channelId, cb, Server) {
     });
 };
 
-Channel.removeOwnedChannel = function (Env, safeKey, channelId, cb, Server) {
-    if (typeof(channelId) !== 'string' || !Core.isValidId(channelId)) {
-        return cb('INVALID_ARGUMENTS');
-    }
+var archiveOwnedChannel = function (Env, safeKey, channelId, cb, Server) {
     var unsafeKey = Util.unescapeKeyCharacters(safeKey);
-
-    if (Env.blobStore.isFileId(channelId)) {
-        return void Env.removeOwnedBlob(channelId, safeKey, cb);
-    }
-
     Metadata.getMetadata(Env, channelId, function (err, metadata) {
         if (err) { return void cb(err); }
         if (!Core.hasOwners(metadata)) { return void cb('E_NO_OWNERS'); }
@@ -124,6 +116,24 @@ Channel.removeOwnedChannel = function (Env, safeKey, channelId, cb, Server) {
     });
 };
 
+Channel.removeOwnedChannel = function (Env, safeKey, channelId, __cb, Server) {
+    var _cb = Util.once(Util.mkAsync(__cb));
+
+    if (typeof(channelId) !== 'string' || !Core.isValidId(channelId)) {
+        return _cb('INVALID_ARGUMENTS');
+    }
+
+    // archiving large channels or files can be expensive, so do it one at a time
+    // for any given user to ensure that nobody can use too much of the server's resources
+    Env.queueDeletes(safeKey, function (next) {
+        var cb = Util.both(_cb, next);
+        if (Env.blobStore.isFileId(channelId)) {
+            return void Env.removeOwnedBlob(channelId, safeKey, cb);
+        }
+        archiveOwnedChannel(Env, safeKey, channelId, cb, Server);
+    });
+};
+
 Channel.trimHistory = function (Env, safeKey, data, cb) {
     if (!(data && typeof(data.channel) === 'string' && typeof(data.hash) === 'string' && data.hash.length === 64)) {
         return void cb('INVALID_ARGS');

lib/historyKeeper.js

@@ -38,6 +38,7 @@ module.exports.create = function (config, cb) {
         metadata_cache: {},
         channel_cache: {},
         queueStorage: WriteQueue(),
+        queueDeletes: WriteQueue(),
 
         batchIndexReads: BatchRead("HK_GET_INDEX"),
         batchMetadata: BatchRead('GET_METADATA'),