From 111de8d803ac416f392ab350975f13dcb593eaf4 Mon Sep 17 00:00:00 2001
From: Slava Kim <slava@meteor.com>
Date: Mon, 28 Oct 2013 14:45:29 -0700
Subject: [PATCH] Oplog observe handles 'drop collection' or db.c.drop()

---
 packages/mongo-livedata/mongo_driver.js | 11 +++++++++--
 packages/mongo-livedata/oplog.js        | 15 ++++++++++++++-
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/packages/mongo-livedata/mongo_driver.js b/packages/mongo-livedata/mongo_driver.js
index b749682988..a9f549f923 100644
--- a/packages/mongo-livedata/mongo_driver.js
+++ b/packages/mongo-livedata/mongo_driver.js
@@ -258,8 +258,10 @@ MongoConnection.prototype._startOplogTailing = function (oplogUrl,
   var baseOplogSelector = _.once(function () {
     return {
       ns: new RegExp('^' + quotemeta(dbNameFuture.wait()) + '\\.'),
-      // XXX also handle drop collection, etc
-      op: {$in: ['i', 'u', 'd']}
+      $or: [
+        { op: {$in: ['i', 'u', 'd']} },
+        // If it is not db.collection.drop(), ignore it
+        { op: 'c', 'o.drop': { $exists: true } }]
     };
   });
   // XXX doc
@@ -403,6 +405,11 @@ MongoConnection.prototype._startOplogTailing = function (oplogUrl,
 
       var collectionName = doc.ns.substr(dbName.length + 1);
 
+      // Is it a special command and the collection name is hidden somewhere in
+      // operator?
+      if (collectionName === "$cmd")
+        collectionName = doc.o.drop;
+
       _.each(callbacksByCollection[collectionName], function (callback) {
         callback(EJSON.clone(doc));
       });
diff --git a/packages/mongo-livedata/oplog.js b/packages/mongo-livedata/oplog.js
index 07706cd1dd..163e01590b 100644
--- a/packages/mongo-livedata/oplog.js
+++ b/packages/mongo-livedata/oplog.js
@@ -14,6 +14,9 @@ var idForOp = function (op) {
     return op.o._id;
   else if (op.op === 'u')
     return op.o2._id;
+  else if (op.op === 'c')
+    throw Error("Operator 'c' doesn't supply an object with id: " +
+                EJSON.stringify(op));
   else
     throw Error("Unknown op: " + EJSON.stringify(op));
 };
@@ -192,7 +195,17 @@ MongoConnection.prototype._observeChangesWithOplog = function (
 
   var oplogEntryHandle = self._oplogHandle.onOplogEntry(
     cursorDescription.collectionName, function (op) {
-      oplogEntryHandlers[phase](op);
+      if (op.op === 'c') {
+        // If it is not db.collection.drop(), ignore it
+        if (op.o && _.isEqual(_.keys(op.o), ['drop'])) {
+          published.each(function (fields, id) {
+            remove(id);
+          });
+        }
+      } else {
+        // All other operators should be handled depending on phase
+        oplogEntryHandlers[phase](op);
+      }
     }
   );