xpcom/ds/nsObserverService.cpp

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "prlog.h"
   7 #include "nsAutoPtr.h"
   8 #include "nsIFactory.h"
   9 #include "nsIServiceManager.h"
  10 #include "nsIComponentManager.h"
  11 #include "nsIObserverService.h"
  12 #include "nsIObserver.h"
  13 #include "nsISimpleEnumerator.h"
  14 #include "nsObserverService.h"
  15 #include "nsObserverList.h"
  16 #include "nsHashtable.h"
  17 #include "nsThreadUtils.h"
  18 #include "nsIWeakReference.h"
  19 #include "nsEnumeratorUtils.h"
  20 #include "mozilla/net/NeckoCommon.h"
  21
  22 #define NOTIFY_GLOBAL_OBSERVERS
  23
  24 #if defined(PR_LOGGING)
  25 // Log module for nsObserverService logging...
  26 //
  27 // To enable logging (see prlog.h for full details):
  28 //
  29 //    set NSPR_LOG_MODULES=ObserverService:5
  30 //    set NSPR_LOG_FILE=nspr.log
  31 //
  32 // this enables PR_LOG_DEBUG level information and places all output in
  33 // the file nspr.log
  34 static PRLogModuleInfo*
  35 GetObserverServiceLog()
  36 {
  37     static PRLogModuleInfo *sLog;
  38     if (!sLog)
  39         sLog = PR_NewLogModule("ObserverService");
  40     return sLog;
  41 }
  42   #define LOG(x)  PR_LOG(GetObserverServiceLog(), PR_LOG_DEBUG, x)
  43 #else
  44   #define LOG(x)
  45 #endif /* PR_LOGGING */
  46
  47 ////////////////////////////////////////////////////////////////////////////////
  48 // nsObserverService Implementation
  49
  50
  51 NS_IMPL_THREADSAFE_ISUPPORTS2(nsObserverService, nsIObserverService, nsObserverService)
  52
  53 nsObserverService::nsObserverService() :
  54     mShuttingDown(false)
  55 {
  56     mObserverTopicTable.Init();
  57 }
  58
  59 nsObserverService::~nsObserverService(void)
  60 {
  61     Shutdown();
  62 }
  63
  64 void
  65 nsObserverService::Shutdown()
  66 {
  67     mShuttingDown = true;
  68
  69     if (mObserverTopicTable.IsInitialized())
  70         mObserverTopicTable.Clear();
  71 }
  72
  73 nsresult
  74 nsObserverService::Create(nsISupports* outer, const nsIID& aIID, void* *aInstancePtr)
  75 {
  76     LOG(("nsObserverService::Create()"));
  77
  78     nsRefPtr<nsObserverService> os = new nsObserverService();
  79
  80     if (!os || !os->mObserverTopicTable.IsInitialized())
  81         return NS_ERROR_OUT_OF_MEMORY;
  82
  83     return os->QueryInterface(aIID, aInstancePtr);
  84 }
  85
  86 #define NS_ENSURE_VALIDCALL \
  87     if (!NS_IsMainThread()) {                                     \
  88         NS_ERROR("Using observer service off the main thread!");  \
  89         return NS_ERROR_UNEXPECTED;                               \
  90     }                                                             \
  91     if (mShuttingDown) {                                          \
  92         NS_ERROR("Using observer service after XPCOM shutdown!"); \
  93         return NS_ERROR_ILLEGAL_DURING_SHUTDOWN;                  \
  94     }
  95
  96 NS_IMETHODIMP
  97 nsObserverService::AddObserver(nsIObserver* anObserver, const char* aTopic,
  98                                bool ownsWeak)
  99 {
 100     LOG(("nsObserverService::AddObserver(%p: %s)",
 101          (void*) anObserver, aTopic));
 102
 103     NS_ENSURE_VALIDCALL
 104     NS_ENSURE_ARG(anObserver && aTopic);
 105
 106     if (mozilla::net::IsNeckoChild() && !strncmp(aTopic, "http-on-", 8)) {
 107       return NS_ERROR_NOT_IMPLEMENTED;
 108     }
 109
 110     nsObserverList *observerList = mObserverTopicTable.PutEntry(aTopic);
 111     if (!observerList)
 112         return NS_ERROR_OUT_OF_MEMORY;
 113
 114     return observerList->AddObserver(anObserver, ownsWeak);
 115 }
 116
 117 NS_IMETHODIMP
 118 nsObserverService::RemoveObserver(nsIObserver* anObserver, const char* aTopic)
 119 {
 120     LOG(("nsObserverService::RemoveObserver(%p: %s)",
 121          (void*) anObserver, aTopic));
 122     NS_ENSURE_VALIDCALL
 123     NS_ENSURE_ARG(anObserver && aTopic);
 124
 125     nsObserverList *observerList = mObserverTopicTable.GetEntry(aTopic);
 126     if (!observerList)
 127         return NS_ERROR_FAILURE;
 128
 129     /* This death grip is to protect against stupid consumers who call
 130        RemoveObserver from their Destructor, see bug 485834/bug 325392. */
 131     nsCOMPtr<nsIObserver> kungFuDeathGrip(anObserver);
 132     return observerList->RemoveObserver(anObserver);
 133 }
 134
 135 NS_IMETHODIMP
 136 nsObserverService::EnumerateObservers(const char* aTopic,
 137                                       nsISimpleEnumerator** anEnumerator)
 138 {
 139     NS_ENSURE_VALIDCALL
 140     NS_ENSURE_ARG(aTopic && anEnumerator);
 141
 142     nsObserverList *observerList = mObserverTopicTable.GetEntry(aTopic);
 143     if (!observerList)
 144         return NS_NewEmptyEnumerator(anEnumerator);
 145
 146     return observerList->GetObserverList(anEnumerator);
 147 }
 148
 149 // Enumerate observers of aTopic and call Observe on each.
 150 NS_IMETHODIMP nsObserverService::NotifyObservers(nsISupports *aSubject,
 151                                                  const char *aTopic,
 152                                                  const PRUnichar *someData)
 153 {
 154     LOG(("nsObserverService::NotifyObservers(%s)", aTopic));
 155
 156     NS_ENSURE_VALIDCALL
 157     NS_ENSURE_ARG(aTopic);
 158
 159     nsObserverList *observerList = mObserverTopicTable.GetEntry(aTopic);
 160     if (observerList)
 161         observerList->NotifyObservers(aSubject, aTopic, someData);
 162
 163 #ifdef NOTIFY_GLOBAL_OBSERVERS
 164     observerList = mObserverTopicTable.GetEntry("*");
 165     if (observerList)
 166         observerList->NotifyObservers(aSubject, aTopic, someData);
 167 #endif
 168
 169     return NS_OK;
 170 }
 171
 172 static PLDHashOperator
 173 UnmarkGrayObserverEntry(nsObserverList* aObserverList, void* aClosure)
 174 {
 175     if (aObserverList) {
 176         aObserverList->UnmarkGrayStrongObservers();
 177     }
 178     return PL_DHASH_NEXT;
 179 }
 180
 181 NS_IMETHODIMP
 182 nsObserverService::UnmarkGrayStrongObservers()
 183 {
 184     NS_ENSURE_VALIDCALL
 185
 186     mObserverTopicTable.EnumerateEntries(UnmarkGrayObserverEntry, nullptr);
 187
 188     return NS_OK;
 189 }