1 files changed, 312 insertions, 0 deletions
diff --git a/xpcom/ds/nsObserverService.cpp b/xpcom/ds/nsObserverService.cpp
new file mode 100644
index 000000000..23cc54fa7
--- /dev/null
+++ b/xpcom/ds/nsObserverService.cpp
@@ -0,0 +1,312 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 "mozilla/Logging.h"
+#include "nsAutoPtr.h"
+#include "nsIConsoleService.h"
+#include "nsIObserverService.h"
+#include "nsIObserver.h"
+#include "nsIScriptError.h"
+#include "nsObserverService.h"
+#include "nsObserverList.h"
+#include "nsServiceManagerUtils.h"
+#include "nsThreadUtils.h"
+#include "nsEnumeratorUtils.h"
+#include "xpcpublic.h"
+#include "mozilla/net/NeckoCommon.h"
+#include "mozilla/Services.h"
+
+#define NOTIFY_GLOBAL_OBSERVERS
+
+// Log module for nsObserverService logging...
+//
+// To enable logging (see prlog.h for full details):
+//
+//    set MOZ_LOG=ObserverService:5
+//    set MOZ_LOG_FILE=service.log
+//
+// This enables LogLevel::Debug level information and places all output in
+// the file service.log.
+static mozilla::LazyLogModule sObserverServiceLog("ObserverService");
+#define LOG(x) MOZ_LOG(sObserverServiceLog, mozilla::LogLevel::Debug, x)
+
+using namespace mozilla;
+
+NS_IMETHODIMP
+nsObserverService::CollectReports(nsIHandleReportCallback* aHandleReport,
+                                  nsISupports* aData, bool aAnonymize)
+{
+  struct SuspectObserver
+  {
+    SuspectObserver(const char* aTopic, size_t aReferentCount)
+      : mTopic(aTopic)
+      , mReferentCount(aReferentCount)
+    {}
+    const char* mTopic;
+    size_t mReferentCount;
+  };
+
+  size_t totalNumStrong = 0;
+  size_t totalNumWeakAlive = 0;
+  size_t totalNumWeakDead = 0;
+  nsTArray<SuspectObserver> suspectObservers;
+
+  for (auto iter = mObserverTopicTable.Iter(); !iter.Done(); iter.Next()) {
+    nsObserverList* observerList = iter.Get();
+    if (!observerList) {
+      continue;
+    }
+
+    size_t topicNumStrong = 0;
+    size_t topicNumWeakAlive = 0;
+    size_t topicNumWeakDead = 0;
+
+    nsTArray<ObserverRef>& observers = observerList->mObservers;
+    for (uint32_t i = 0; i < observers.Length(); i++) {
+      if (observers[i].isWeakRef) {
+        nsCOMPtr<nsIObserver> observerRef(
+          do_QueryReferent(observers[i].asWeak()));
+        if (observerRef) {
+          topicNumWeakAlive++;
+        } else {
+          topicNumWeakDead++;
+        }
+      } else {
+        topicNumStrong++;
+      }
+    }
+
+    totalNumStrong += topicNumStrong;
+    totalNumWeakAlive += topicNumWeakAlive;
+    totalNumWeakDead += topicNumWeakDead;
+
+    // Keep track of topics that have a suspiciously large number
+    // of referents (symptom of leaks).
+    size_t topicTotal = topicNumStrong + topicNumWeakAlive + topicNumWeakDead;
+    if (topicTotal > kSuspectReferentCount) {
+      SuspectObserver suspect(observerList->GetKey(), topicTotal);
+      suspectObservers.AppendElement(suspect);
+    }
+  }
+
+  // These aren't privacy-sensitive and so don't need anonymizing.
+  for (uint32_t i = 0; i < suspectObservers.Length(); i++) {
+    SuspectObserver& suspect = suspectObservers[i];
+    nsPrintfCString suspectPath("observer-service-suspect/referent(topic=%s)",
+                                suspect.mTopic);
+    aHandleReport->Callback(
+      /* process */ EmptyCString(),
+      suspectPath, KIND_OTHER, UNITS_COUNT, suspect.mReferentCount,
+      NS_LITERAL_CSTRING("A topic with a suspiciously large number of "
+                         "referents.  This may be symptomatic of a leak "
+                         "if the number of referents is high with "
+                         "respect to the number of windows."),
+      aData);
+  }
+
+  MOZ_COLLECT_REPORT(
+    "observer-service/referent/strong", KIND_OTHER, UNITS_COUNT,
+    totalNumStrong,
+    "The number of strong references held by the observer service.");
+
+  MOZ_COLLECT_REPORT(
+    "observer-service/referent/weak/alive", KIND_OTHER, UNITS_COUNT,
+    totalNumWeakAlive,
+    "The number of weak references held by the observer service that are "
+    "still alive.");
+
+  MOZ_COLLECT_REPORT(
+    "observer-service/referent/weak/dead", KIND_OTHER, UNITS_COUNT,
+    totalNumWeakDead,
+    "The number of weak references held by the observer service that are "
+    "dead.");
+
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// nsObserverService Implementation
+
+NS_IMPL_ISUPPORTS(nsObserverService,
+                  nsIObserverService,
+                  nsObserverService,
+                  nsIMemoryReporter)
+
+nsObserverService::nsObserverService()
+  : mShuttingDown(false)
+{
+}
+
+nsObserverService::~nsObserverService(void)
+{
+  Shutdown();
+}
+
+void
+nsObserverService::RegisterReporter()
+{
+  RegisterWeakMemoryReporter(this);
+}
+
+void
+nsObserverService::Shutdown()
+{
+  UnregisterWeakMemoryReporter(this);
+
+  mShuttingDown = true;
+
+  mObserverTopicTable.Clear();
+}
+
+nsresult
+nsObserverService::Create(nsISupports* aOuter, const nsIID& aIID,
+                          void** aInstancePtr)
+{
+  LOG(("nsObserverService::Create()"));
+
+  RefPtr<nsObserverService> os = new nsObserverService();
+
+  if (!os) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  // The memory reporter can not be immediately registered here because
+  // the nsMemoryReporterManager may attempt to get the nsObserverService
+  // during initialization, causing a recursive GetService.
+  NS_DispatchToCurrentThread(NewRunnableMethod(os, &nsObserverService::RegisterReporter));
+
+  return os->QueryInterface(aIID, aInstancePtr);
+}
+
+#define NS_ENSURE_VALIDCALL \
+    if (!NS_IsMainThread()) {                                     \
+        MOZ_CRASH("Using observer service off the main thread!"); \
+        return NS_ERROR_UNEXPECTED;                               \
+    }                                                             \
+    if (mShuttingDown) {                                          \
+        NS_ERROR("Using observer service after XPCOM shutdown!"); \
+        return NS_ERROR_ILLEGAL_DURING_SHUTDOWN;                  \
+    }
+
+NS_IMETHODIMP
+nsObserverService::AddObserver(nsIObserver* aObserver, const char* aTopic,
+                               bool aOwnsWeak)
+{
+  LOG(("nsObserverService::AddObserver(%p: %s)",
+       (void*)aObserver, aTopic));
+
+  NS_ENSURE_VALIDCALL
+  if (NS_WARN_IF(!aObserver) || NS_WARN_IF(!aTopic)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  // Specifically allow http-on-opening-request in the child process;
+  // see bug 1269765.
+  if (mozilla::net::IsNeckoChild() && !strncmp(aTopic, "http-on-", 8) &&
+      strcmp(aTopic, "http-on-opening-request")) {
+    nsCOMPtr<nsIConsoleService> console(do_GetService(NS_CONSOLESERVICE_CONTRACTID));
+    nsCOMPtr<nsIScriptError> error(do_CreateInstance(NS_SCRIPTERROR_CONTRACTID));
+    error->Init(NS_LITERAL_STRING("http-on-* observers only work in the parent process"),
+                EmptyString(), EmptyString(), 0, 0,
+                nsIScriptError::warningFlag, "chrome javascript");
+    console->LogMessage(error);
+
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+
+  nsObserverList* observerList = mObserverTopicTable.PutEntry(aTopic);
+  if (!observerList) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  return observerList->AddObserver(aObserver, aOwnsWeak);
+}
+
+NS_IMETHODIMP
+nsObserverService::RemoveObserver(nsIObserver* aObserver, const char* aTopic)
+{
+  LOG(("nsObserverService::RemoveObserver(%p: %s)",
+       (void*)aObserver, aTopic));
+  NS_ENSURE_VALIDCALL
+  if (NS_WARN_IF(!aObserver) || NS_WARN_IF(!aTopic)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  nsObserverList* observerList = mObserverTopicTable.GetEntry(aTopic);
+  if (!observerList) {
+    return NS_ERROR_FAILURE;
+  }
+
+  /* This death grip is to protect against stupid consumers who call
+     RemoveObserver from their Destructor, see bug 485834/bug 325392. */
+  nsCOMPtr<nsIObserver> kungFuDeathGrip(aObserver);
+  return observerList->RemoveObserver(aObserver);
+}
+
+NS_IMETHODIMP
+nsObserverService::EnumerateObservers(const char* aTopic,
+                                      nsISimpleEnumerator** anEnumerator)
+{
+  NS_ENSURE_VALIDCALL
+  if (NS_WARN_IF(!anEnumerator) || NS_WARN_IF(!aTopic)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  nsObserverList* observerList = mObserverTopicTable.GetEntry(aTopic);
+  if (!observerList) {
+    return NS_NewEmptyEnumerator(anEnumerator);
+  }
+
+  observerList->GetObserverList(anEnumerator);
+  return NS_OK;
+}
+
+// Enumerate observers of aTopic and call Observe on each.
+NS_IMETHODIMP nsObserverService::NotifyObservers(nsISupports* aSubject,
+                                                 const char* aTopic,
+                                                 const char16_t* aSomeData)
+{
+  LOG(("nsObserverService::NotifyObservers(%s)", aTopic));
+
+  NS_ENSURE_VALIDCALL
+  if (NS_WARN_IF(!aTopic)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  nsObserverList* observerList = mObserverTopicTable.GetEntry(aTopic);
+  if (observerList) {
+    observerList->NotifyObservers(aSubject, aTopic, aSomeData);
+  }
+
+#ifdef NOTIFY_GLOBAL_OBSERVERS
+  observerList = mObserverTopicTable.GetEntry("*");
+  if (observerList) {
+    observerList->NotifyObservers(aSubject, aTopic, aSomeData);
+  }
+#endif
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsObserverService::UnmarkGrayStrongObservers()
+{
+  NS_ENSURE_VALIDCALL
+
+  nsCOMArray<nsIObserver> strongObservers;
+  for (auto iter = mObserverTopicTable.Iter(); !iter.Done(); iter.Next()) {
+    nsObserverList* aObserverList = iter.Get();
+    if (aObserverList) {
+      aObserverList->AppendStrongObservers(strongObservers);
+    }
+  }
+
+  for (uint32_t i = 0; i < strongObservers.Length(); ++i) {
+    xpc_TryUnmarkWrappedGrayObject(strongObservers[i]);
+  }
+
+  return NS_OK;
+}