1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/xpcom/ds/nsObserverService.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,331 @@
1.4 +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#include "prlog.h"
1.10 +#include "nsAutoPtr.h"
1.11 +#include "nsIObserverService.h"
1.12 +#include "nsIObserver.h"
1.13 +#include "nsObserverService.h"
1.14 +#include "nsObserverList.h"
1.15 +#include "nsThreadUtils.h"
1.16 +#include "nsEnumeratorUtils.h"
1.17 +#include "mozilla/net/NeckoCommon.h"
1.18 +#include "mozilla/Services.h"
1.19 +
1.20 +#define NOTIFY_GLOBAL_OBSERVERS
1.21 +
1.22 +#if defined(PR_LOGGING)
1.23 +// Log module for nsObserverService logging...
1.24 +//
1.25 +// To enable logging (see prlog.h for full details):
1.26 +//
1.27 +// set NSPR_LOG_MODULES=ObserverService:5
1.28 +// set NSPR_LOG_FILE=nspr.log
1.29 +//
1.30 +// this enables PR_LOG_DEBUG level information and places all output in
1.31 +// the file nspr.log
1.32 +static PRLogModuleInfo*
1.33 +GetObserverServiceLog()
1.34 +{
1.35 + static PRLogModuleInfo *sLog;
1.36 + if (!sLog)
1.37 + sLog = PR_NewLogModule("ObserverService");
1.38 + return sLog;
1.39 +}
1.40 + #define LOG(x) PR_LOG(GetObserverServiceLog(), PR_LOG_DEBUG, x)
1.41 +#else
1.42 + #define LOG(x)
1.43 +#endif /* PR_LOGGING */
1.44 +
1.45 +namespace mozilla {
1.46 +
1.47 +struct SuspectObserver {
1.48 + SuspectObserver(const char* aTopic, size_t aReferentCount)
1.49 + : topic(aTopic), referentCount(aReferentCount) {}
1.50 + const char* topic;
1.51 + size_t referentCount;
1.52 +};
1.53 +
1.54 +struct ObserverServiceReferentCount {
1.55 + ObserverServiceReferentCount()
1.56 + : numStrong(0), numWeakAlive(0), numWeakDead(0) {}
1.57 + size_t numStrong;
1.58 + size_t numWeakAlive;
1.59 + size_t numWeakDead;
1.60 + nsTArray<SuspectObserver> suspectObservers;
1.61 +};
1.62 +
1.63 +} // namespace mozilla
1.64 +
1.65 +using namespace mozilla;
1.66 +
1.67 +PLDHashOperator
1.68 +nsObserverService::CountReferents(nsObserverList* aObserverList,
1.69 + void* aClosure)
1.70 +{
1.71 + if (!aObserverList) {
1.72 + return PL_DHASH_NEXT;
1.73 + }
1.74 +
1.75 + ObserverServiceReferentCount* referentCount =
1.76 + static_cast<ObserverServiceReferentCount*>(aClosure);
1.77 +
1.78 + size_t numStrong = 0;
1.79 + size_t numWeakAlive = 0;
1.80 + size_t numWeakDead = 0;
1.81 +
1.82 + nsTArray<ObserverRef>& observers = aObserverList->mObservers;
1.83 + for (uint32_t i = 0; i < observers.Length(); i++) {
1.84 + if (observers[i].isWeakRef) {
1.85 + nsCOMPtr<nsIObserver> observerRef(
1.86 + do_QueryReferent(observers[i].asWeak()));
1.87 + if (observerRef) {
1.88 + numWeakAlive++;
1.89 + } else {
1.90 + numWeakDead++;
1.91 + }
1.92 + } else {
1.93 + numStrong++;
1.94 + }
1.95 + }
1.96 +
1.97 + referentCount->numStrong += numStrong;
1.98 + referentCount->numWeakAlive += numWeakAlive;
1.99 + referentCount->numWeakDead += numWeakDead;
1.100 +
1.101 + // Keep track of topics that have a suspiciously large number
1.102 + // of referents (symptom of leaks).
1.103 + size_t total = numStrong + numWeakAlive + numWeakDead;
1.104 + if (total > kSuspectReferentCount) {
1.105 + SuspectObserver suspect(aObserverList->GetKey(), total);
1.106 + referentCount->suspectObservers.AppendElement(suspect);
1.107 + }
1.108 +
1.109 + return PL_DHASH_NEXT;
1.110 +}
1.111 +
1.112 +NS_IMETHODIMP
1.113 +nsObserverService::CollectReports(nsIHandleReportCallback* aHandleReport,
1.114 + nsISupports* aData)
1.115 +{
1.116 + ObserverServiceReferentCount referentCount;
1.117 + mObserverTopicTable.EnumerateEntries(CountReferents, &referentCount);
1.118 +
1.119 + nsresult rv;
1.120 + for (uint32_t i = 0; i < referentCount.suspectObservers.Length(); i++) {
1.121 + SuspectObserver& suspect = referentCount.suspectObservers[i];
1.122 + nsPrintfCString suspectPath("observer-service-suspect/"
1.123 + "referent(topic=%s)",
1.124 + suspect.topic);
1.125 + rv = aHandleReport->Callback(/* process */ EmptyCString(),
1.126 + suspectPath, KIND_OTHER, UNITS_COUNT, suspect.referentCount,
1.127 + NS_LITERAL_CSTRING("A topic with a suspiciously large number of "
1.128 + "referents. This may be symptomatic of a leak "
1.129 + "if the number of referents is high with "
1.130 + "respect to the number of windows."),
1.131 + aData);
1.132 +
1.133 + if (NS_WARN_IF(NS_FAILED(rv)))
1.134 + return rv;
1.135 + }
1.136 +
1.137 + rv = aHandleReport->Callback(/* process */ EmptyCString(),
1.138 + NS_LITERAL_CSTRING("observer-service/referent/strong"),
1.139 + KIND_OTHER, UNITS_COUNT, referentCount.numStrong,
1.140 + NS_LITERAL_CSTRING("The number of strong references held by the "
1.141 + "observer service."),
1.142 + aData);
1.143 +
1.144 + if (NS_WARN_IF(NS_FAILED(rv)))
1.145 + return rv;
1.146 +
1.147 + rv = aHandleReport->Callback(/* process */ EmptyCString(),
1.148 + NS_LITERAL_CSTRING("observer-service/referent/weak/alive"),
1.149 + KIND_OTHER, UNITS_COUNT, referentCount.numWeakAlive,
1.150 + NS_LITERAL_CSTRING("The number of weak references held by the "
1.151 + "observer service that are still alive."),
1.152 + aData);
1.153 +
1.154 + if (NS_WARN_IF(NS_FAILED(rv)))
1.155 + return rv;
1.156 +
1.157 + rv = aHandleReport->Callback(/* process */ EmptyCString(),
1.158 + NS_LITERAL_CSTRING("observer-service/referent/weak/dead"),
1.159 + KIND_OTHER, UNITS_COUNT, referentCount.numWeakDead,
1.160 + NS_LITERAL_CSTRING("The number of weak references held by the "
1.161 + "observer service that are dead."),
1.162 + aData);
1.163 +
1.164 + if (NS_WARN_IF(NS_FAILED(rv)))
1.165 + return rv;
1.166 +
1.167 + return NS_OK;
1.168 +}
1.169 +
1.170 +////////////////////////////////////////////////////////////////////////////////
1.171 +// nsObserverService Implementation
1.172 +
1.173 +
1.174 +NS_IMPL_ISUPPORTS(
1.175 + nsObserverService,
1.176 + nsIObserverService,
1.177 + nsObserverService,
1.178 + nsIMemoryReporter)
1.179 +
1.180 +nsObserverService::nsObserverService() :
1.181 + mShuttingDown(false)
1.182 +{
1.183 +}
1.184 +
1.185 +nsObserverService::~nsObserverService(void)
1.186 +{
1.187 + Shutdown();
1.188 +}
1.189 +
1.190 +void
1.191 +nsObserverService::RegisterReporter()
1.192 +{
1.193 + RegisterWeakMemoryReporter(this);
1.194 +}
1.195 +
1.196 +void
1.197 +nsObserverService::Shutdown()
1.198 +{
1.199 + UnregisterWeakMemoryReporter(this);
1.200 +
1.201 + mShuttingDown = true;
1.202 +
1.203 + mObserverTopicTable.Clear();
1.204 +}
1.205 +
1.206 +nsresult
1.207 +nsObserverService::Create(nsISupports* outer, const nsIID& aIID, void* *aInstancePtr)
1.208 +{
1.209 + LOG(("nsObserverService::Create()"));
1.210 +
1.211 + nsRefPtr<nsObserverService> os = new nsObserverService();
1.212 +
1.213 + if (!os)
1.214 + return NS_ERROR_OUT_OF_MEMORY;
1.215 +
1.216 + // The memory reporter can not be immediately registered here because
1.217 + // the nsMemoryReporterManager may attempt to get the nsObserverService
1.218 + // during initialization, causing a recursive GetService.
1.219 + nsRefPtr<nsRunnableMethod<nsObserverService> > registerRunnable =
1.220 + NS_NewRunnableMethod(os, &nsObserverService::RegisterReporter);
1.221 + NS_DispatchToCurrentThread(registerRunnable);
1.222 +
1.223 + return os->QueryInterface(aIID, aInstancePtr);
1.224 +}
1.225 +
1.226 +#define NS_ENSURE_VALIDCALL \
1.227 + if (!NS_IsMainThread()) { \
1.228 + MOZ_CRASH("Using observer service off the main thread!"); \
1.229 + return NS_ERROR_UNEXPECTED; \
1.230 + } \
1.231 + if (mShuttingDown) { \
1.232 + NS_ERROR("Using observer service after XPCOM shutdown!"); \
1.233 + return NS_ERROR_ILLEGAL_DURING_SHUTDOWN; \
1.234 + }
1.235 +
1.236 +NS_IMETHODIMP
1.237 +nsObserverService::AddObserver(nsIObserver* anObserver, const char* aTopic,
1.238 + bool ownsWeak)
1.239 +{
1.240 + LOG(("nsObserverService::AddObserver(%p: %s)",
1.241 + (void*) anObserver, aTopic));
1.242 +
1.243 + NS_ENSURE_VALIDCALL
1.244 + if (NS_WARN_IF(!anObserver) || NS_WARN_IF(!aTopic))
1.245 + return NS_ERROR_INVALID_ARG;
1.246 +
1.247 + if (mozilla::net::IsNeckoChild() && !strncmp(aTopic, "http-on-", 8)) {
1.248 + return NS_ERROR_NOT_IMPLEMENTED;
1.249 + }
1.250 +
1.251 + nsObserverList *observerList = mObserverTopicTable.PutEntry(aTopic);
1.252 + if (!observerList)
1.253 + return NS_ERROR_OUT_OF_MEMORY;
1.254 +
1.255 + return observerList->AddObserver(anObserver, ownsWeak);
1.256 +}
1.257 +
1.258 +NS_IMETHODIMP
1.259 +nsObserverService::RemoveObserver(nsIObserver* anObserver, const char* aTopic)
1.260 +{
1.261 + LOG(("nsObserverService::RemoveObserver(%p: %s)",
1.262 + (void*) anObserver, aTopic));
1.263 + NS_ENSURE_VALIDCALL
1.264 + if (NS_WARN_IF(!anObserver) || NS_WARN_IF(!aTopic))
1.265 + return NS_ERROR_INVALID_ARG;
1.266 +
1.267 + nsObserverList *observerList = mObserverTopicTable.GetEntry(aTopic);
1.268 + if (!observerList)
1.269 + return NS_ERROR_FAILURE;
1.270 +
1.271 + /* This death grip is to protect against stupid consumers who call
1.272 + RemoveObserver from their Destructor, see bug 485834/bug 325392. */
1.273 + nsCOMPtr<nsIObserver> kungFuDeathGrip(anObserver);
1.274 + return observerList->RemoveObserver(anObserver);
1.275 +}
1.276 +
1.277 +NS_IMETHODIMP
1.278 +nsObserverService::EnumerateObservers(const char* aTopic,
1.279 + nsISimpleEnumerator** anEnumerator)
1.280 +{
1.281 + NS_ENSURE_VALIDCALL
1.282 + if (NS_WARN_IF(!anEnumerator) || NS_WARN_IF(!aTopic))
1.283 + return NS_ERROR_INVALID_ARG;
1.284 +
1.285 + nsObserverList *observerList = mObserverTopicTable.GetEntry(aTopic);
1.286 + if (!observerList)
1.287 + return NS_NewEmptyEnumerator(anEnumerator);
1.288 +
1.289 + return observerList->GetObserverList(anEnumerator);
1.290 +}
1.291 +
1.292 +// Enumerate observers of aTopic and call Observe on each.
1.293 +NS_IMETHODIMP nsObserverService::NotifyObservers(nsISupports *aSubject,
1.294 + const char *aTopic,
1.295 + const char16_t *someData)
1.296 +{
1.297 + LOG(("nsObserverService::NotifyObservers(%s)", aTopic));
1.298 +
1.299 + NS_ENSURE_VALIDCALL
1.300 + if (NS_WARN_IF(!aTopic))
1.301 + return NS_ERROR_INVALID_ARG;
1.302 +
1.303 + nsObserverList *observerList = mObserverTopicTable.GetEntry(aTopic);
1.304 + if (observerList)
1.305 + observerList->NotifyObservers(aSubject, aTopic, someData);
1.306 +
1.307 +#ifdef NOTIFY_GLOBAL_OBSERVERS
1.308 + observerList = mObserverTopicTable.GetEntry("*");
1.309 + if (observerList)
1.310 + observerList->NotifyObservers(aSubject, aTopic, someData);
1.311 +#endif
1.312 +
1.313 + return NS_OK;
1.314 +}
1.315 +
1.316 +static PLDHashOperator
1.317 +UnmarkGrayObserverEntry(nsObserverList* aObserverList, void* aClosure)
1.318 +{
1.319 + if (aObserverList) {
1.320 + aObserverList->UnmarkGrayStrongObservers();
1.321 + }
1.322 + return PL_DHASH_NEXT;
1.323 +}
1.324 +
1.325 +NS_IMETHODIMP
1.326 +nsObserverService::UnmarkGrayStrongObservers()
1.327 +{
1.328 + NS_ENSURE_VALIDCALL
1.329 +
1.330 + mObserverTopicTable.EnumerateEntries(UnmarkGrayObserverEntry, nullptr);
1.331 +
1.332 + return NS_OK;
1.333 +}
1.334 +
