Bug 576621 - clearing cache does NOT clear cached images.r=joe,gavin

browser/base/content/sanitize.js

@@ -122,6 +122,12 @@ Sanitizer.prototype = {
           // facility for timespan-based eviction.  Wipe it.
           cacheService.evictEntries(Ci.nsICache.STORE_ANYWHERE);
         } catch(er) {}
+
+        var imageCache = Cc["@mozilla.org/image/cache;1"].
+                         getService(Ci.imgICache);
+        try {
+          imageCache.clearCache(false); // true=chrome, false=content
+        } catch(er) {}
       },
       
       get canClear()

browser/components/privatebrowsing/src/nsPrivateBrowsingService.js

@@ -571,6 +571,17 @@ PrivateBrowsingService.prototype = {
       }
     }
 
+    // Image Cache
+    let (imageCache = Cc["@mozilla.org/image/cache;1"].
+                      getService(Ci.imgICache)) {
+      try {
+        imageCache.clearCache(false); // true=chrome, false=content
+      } catch (ex) {
+        Cu.reportError("Exception thrown while clearing the image cache: " +
+          ex.toString());
+      }
+    }
+
     // Cookies
     let (cm = Cc["@mozilla.org/cookiemanager;1"].
               getService(Ci.nsICookieManager2)) {

modules/libpr0n/src/imgLoader.cpp

@@ -78,6 +78,7 @@
 #include "nsIApplicationCacheContainer.h"
 
 #include "nsIMemoryReporter.h"
+#include "nsIPrivateBrowsingService.h"
 
 // we want to explore making the document own the load group
 // so we can associate the document URI with the load group.
@@ -874,19 +875,36 @@ nsresult imgLoader::Init()
 
   prefs->AddObserver("image.http.accept", this, PR_TRUE);
 
+  // Listen for when we leave private browsing mode
+  nsCOMPtr<nsIObserverService> obService = mozilla::services::GetObserverService();
+  if (obService)
+    obService->AddObserver(this, NS_PRIVATE_BROWSING_SWITCH_TOPIC, PR_TRUE);
+
   return NS_OK;
 }
 
 NS_IMETHODIMP
 imgLoader::Observe(nsISupports* aSubject, const char* aTopic, const PRUnichar* aData)
 {
-  NS_ASSERTION(strcmp(aTopic, NS_PREFBRANCH_PREFCHANGE_TOPIC_ID) == 0,
-               "invalid topic received");
-
-  if (strcmp(NS_ConvertUTF16toUTF8(aData).get(), "image.http.accept") == 0) {
-    nsCOMPtr<nsIPrefBranch> prefs = do_QueryInterface(aSubject);
-    ReadAcceptHeaderPref(prefs);
+  // We listen for pref change notifications...
+  if (!strcmp(aTopic, NS_PREFBRANCH_PREFCHANGE_TOPIC_ID)) {
+    if (!strcmp(NS_ConvertUTF16toUTF8(aData).get(), "image.http.accept")) {
+      nsCOMPtr<nsIPrefBranch> prefs = do_QueryInterface(aSubject);
+      ReadAcceptHeaderPref(prefs);
+    }
   }
+
+  // ...and exits from private browsing.
+  else if (!strcmp(aTopic, NS_PRIVATE_BROWSING_SWITCH_TOPIC)) {
+    if (NS_LITERAL_STRING(NS_PRIVATE_BROWSING_LEAVE).Equals(aData))
+      ClearImageCache();
+  }
+
+  // (Nothing else should bring us here)
+  else {
+    NS_ABORT_IF_FALSE(0, "Invalid topic received");
+  }
+
   return NS_OK;
 }