Bug 781700: Don't hold strong references to databases from the synchronization queue, so that GCing a database will unblock waiting operations. r=bent

--HG--
extra : rebase_source : 2f1b2405ffc91831d33eb91e4b2d61c2b1ac872b

dom/indexedDB/IndexedDatabaseManager.cpp

@@ -1181,7 +1181,7 @@ IndexedDatabaseManager::RunSynchronizedOp(IDBDatabase* aDatabase,
   FileService* service = FileService::Get();
   TransactionThreadPool* pool = TransactionThreadPool::Get();
 
-  nsTArray<nsRefPtr<IDBDatabase> > databases;
+  nsTArray<IDBDatabase*> databases;
   if (aDatabase) {
     if (service || pool) {
       databases.AppendElement(aDatabase);

dom/indexedDB/IndexedDatabaseManager.h

@@ -379,7 +379,7 @@ private:
     nsRefPtr<AsyncConnectionHelper> mHelper;
     nsCOMPtr<nsIRunnable> mRunnable;
     nsTArray<nsCOMPtr<nsIRunnable> > mDelayedRunnables;
-    nsTArray<nsRefPtr<IDBDatabase> > mDatabases;
+    nsTArray<IDBDatabase*> mDatabases;
   };
 
   // A callback runnable used by the TransactionPool when it's safe to proceed

dom/indexedDB/TransactionThreadPool.cpp

@@ -450,8 +450,8 @@ TransactionThreadPool::Dispatch(IDBTransaction* aTransaction,
 
 bool
 TransactionThreadPool::WaitForAllDatabasesToComplete(
-                                   nsTArray<nsRefPtr<IDBDatabase> >& aDatabases,
-                                   nsIRunnable* aCallback)
+                                            nsTArray<IDBDatabase*>& aDatabases,
+                                            nsIRunnable* aCallback)
 {
   NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");
   NS_ASSERTION(!aDatabases.IsEmpty(), "No databases to wait on!");

dom/indexedDB/TransactionThreadPool.h

@@ -46,9 +46,8 @@ public:
                     bool aFinish,
                     nsIRunnable* aFinishRunnable);
 
-  bool WaitForAllDatabasesToComplete(
-                                   nsTArray<nsRefPtr<IDBDatabase> >& aDatabases,
-                                   nsIRunnable* aCallback);
+  bool WaitForAllDatabasesToComplete(nsTArray<IDBDatabase*>& aDatabases,
+                                     nsIRunnable* aCallback);
 
   // Abort all transactions, unless they are already in the process of being
   // committed, for aDatabase.
@@ -107,7 +106,7 @@ protected:
 
   struct DatabasesCompleteCallback
   {
-    nsTArray<nsRefPtr<IDBDatabase> > mDatabases;
+    nsTArray<IDBDatabase*> mDatabases;
     nsCOMPtr<nsIRunnable> mCallback;
   };
 

dom/indexedDB/test/helpers.js

@@ -202,3 +202,9 @@ function resetUnlimitedQuota(url)
 {
   removePermission("indexedDB-unlimited", url);
 }
+
+function gc()
+{
+  SpecialPowers.forceGC();
+  SpecialPowers.forceCC();
+}

dom/indexedDB/test/unit/head.js

@@ -172,6 +172,12 @@ function disallowUnlimitedQuota(url)
   throw "disallowUnlimitedQuota";
 }
 
+function gc()
+{
+  Components.utils.forceGC();
+  Components.utils.forceCC();
+}
+
 var SpecialPowers = {
   isMainProcess: function() {
     return Components.classes["@mozilla.org/xre/app-info;1"]

dom/indexedDB/test/unit/test_setVersion_events.js

@@ -113,12 +113,29 @@ function testSteps()
   is(event.oldVersion, 2, "Correct event oldVersion");
   is(event.newVersion, 3, "Correct event newVersion");
   versionChangeEventCount++;
+  // Test one closed explicitly, and one closed by GC.
   db2.close();
-  db3.close();
+  db3 = null;
+  gc();
 
   request.onupgradeneeded = grabEventAndContinueHandler;
   request.onsuccess = grabEventAndContinueHandler;
 
+  executeSoon(function() { testGenerator.next(); });
+  yield;
+  gc();
+
+  if (!this.window) {
+    // In xpcshell, we need to spin the event loop to ensure that GCd things
+    // are finalized (since XPConnect does deferred finalization).
+    let thread = Components.classes["@mozilla.org/thread-manager;1"]
+                           .getService(Components.interfaces.nsIThreadManager)
+                           .currentThread;
+    while (thread.hasPendingEvents()) {
+      thread.processNextEvent(false);
+    }
+  }
+
   event = yield;
   event = yield;
 

js/xpconnect/idl/xpccomponents.idl

@@ -118,7 +118,7 @@ interface ScheduledGCCallback : nsISupports
 /**
 * interface of Components.utils
 */
-[scriptable, uuid(2df24c04-f1ef-481c-8605-433082a34e95)]
+[scriptable, uuid(cc7ef3b0-339d-4317-927b-fdc8f0664927)]
 interface nsIXPCComponents_Utils : nsISupports
 {
 
@@ -228,6 +228,13 @@ interface nsIXPCComponents_Utils : nsISupports
      * Force an immediate garbage collection cycle.
      */
     void forceGC();
+
+    /*
+     * To be called from JS only.
+     *
+     * Force an immediate cycle collection cycle.
+     */
+    void forceCC();
     
     /*
      * To be called from JS only.

js/xpconnect/src/XPCComponents.cpp

@@ -32,6 +32,7 @@
 #include "nsPrincipal.h"
 #include "mozilla/Attributes.h"
 #include "nsIScriptContext.h"
+#include "nsJSEnvironment.h"
 
 using namespace mozilla;
 using namespace js;
@@ -4048,6 +4049,14 @@ nsXPCComponents_Utils::ForceGC()
     return NS_OK;
 }
 
+/* void forceCC (); */
+NS_IMETHODIMP
+nsXPCComponents_Utils::ForceCC()
+{
+    nsJSContext::CycleCollectNow(nullptr, 0);
+    return NS_OK;
+}
+
 /* void forceShrinkingGC (); */
 NS_IMETHODIMP
 nsXPCComponents_Utils::ForceShrinkingGC()

js/xpconnect/src/nsXPConnect.cpp

@@ -38,6 +38,7 @@
 
 #include "nsWrapperCacheInlines.h"
 #include "nsDOMMutationObserver.h"
+#include "nsICycleCollectorListener.h"
 
 using namespace mozilla::dom;
 using namespace xpc;
@@ -2970,5 +2971,25 @@ JS_EXPORT_API(void) DumpJSValue(JS::Value val)
         printf("No idea what this value is.\n");
     }
 }
+
+JS_EXPORT_API(void) DumpCompleteHeap()
+{
+    nsCOMPtr<nsICycleCollectorListener> listener =
+      do_CreateInstance("@mozilla.org/cycle-collector-logger;1");
+    if (!listener) {
+      NS_WARNING("Failed to create CC logger");
+      return;
+    }
+
+    nsCOMPtr<nsICycleCollectorListener> alltracesListener;
+    listener->AllTraces(getter_AddRefs(alltracesListener));
+    if (!alltracesListener) {
+      NS_WARNING("Failed to get all traces logger");
+      return;
+    }
+
+    nsJSContext::CycleCollectNow(alltracesListener);
+}
+
 JS_END_EXTERN_C
 

testing/mochitest/tests/SimpleTest/specialpowersAPI.js

@@ -834,6 +834,10 @@ SpecialPowersAPI.prototype = {
     Components.utils.forceGC();
   },
 
+  forceCC: function() {
+    Components.utils.forceCC();
+  },
+
   exactGC: function(win, callback) {
     var self = this;
     let count = 0;