Bug 964898 - Auto delete unused cache version data on demand, r=jduell

netwerk/cache/moz.build

@@ -18,6 +18,7 @@ XPIDL_MODULE = 'necko_cache'
 EXPORTS += [
     'nsApplicationCacheService.h',
     'nsCacheService.h',
+    'nsDeleteDir.h'
 ]
 
 # These files cannot be built in unified mode because they force NSPR logging.

netwerk/cache/nsCacheService.cpp

@@ -3053,6 +3053,23 @@ nsCacheService::GetClearingEntries()
     return gService->mClearingEntries;
 }
 
+// static
+void nsCacheService::GetDiskCacheDirectory(nsIFile ** result) {
+    *result = nullptr;
+    if (gService && gService->mObserver) {
+        nsCOMPtr<nsIFile> directory =
+            gService->mObserver->DiskCacheParentDirectory();
+        if (!directory)
+            return;
+
+        nsresult rv = directory->AppendNative(NS_LITERAL_CSTRING("Cache"));
+        if (NS_FAILED(rv))
+            return;
+
+        directory.forget(result);
+    }
+}
+
 
 #if defined(PR_LOGGING)
 void

netwerk/cache/nsCacheService.h

@@ -127,6 +127,8 @@ public:
 
     static bool      GetClearingEntries();
 
+    static void      GetDiskCacheDirectory(nsIFile ** result);
+
     /**
      * Methods called by any cache classes
      */

netwerk/cache2/CacheFileIOManager.cpp

@@ -1611,6 +1611,19 @@ CacheFileIOManager::EnumerateEntryFiles(EEnumerateMode aMode,
   return NS_OK;
 }
 
+// static
+void CacheFileIOManager::GetCacheDirectory(nsIFile** result)
+{
+  *result = nullptr;
+
+  nsRefPtr<CacheFileIOManager> ioMan = gInstance;
+  if (!ioMan)
+    return;
+
+  nsCOMPtr<nsIFile> file = ioMan->mCacheDirectory;
+  file.forget(result);
+}
+
 static nsresult
 TruncFile(PRFileDesc *aFD, uint32_t aEOF)
 {

netwerk/cache2/CacheFileIOManager.h

@@ -224,6 +224,8 @@ public:
   static nsresult EnumerateEntryFiles(EEnumerateMode aMode,
                                       CacheEntriesEnumerator** aEnumerator);
 
+  static void GetCacheDirectory(nsIFile** result);
+
 private:
   friend class CacheFileHandle;
   friend class CacheFileChunk;

netwerk/cache2/CacheObserver.cpp

@@ -25,6 +25,8 @@ uint32_t CacheObserver::sMemoryLimit = kDefaultMemoryLimit;
 
 static uint32_t const kDefaultUseNewCache = 0; // Don't use the new cache by default
 uint32_t CacheObserver::sUseNewCache = kDefaultUseNewCache;
+static int32_t const kAutoDeleteCacheVersion = -1; // Auto-delete off by default
+static int32_t sAutoDeleteCacheVersion = kAutoDeleteCacheVersion;
 
 static int32_t const kDefaultHalfLifeExperiment = -1; // Disabled
 int32_t CacheObserver::sHalfLifeExperiment = kDefaultHalfLifeExperiment;
@@ -71,6 +73,7 @@ CacheObserver::Init()
 
   obs->AddObserver(sSelf, "prefservice:after-app-defaults", true);
   obs->AddObserver(sSelf, "profile-do-change", true);
+  obs->AddObserver(sSelf, "sessionstore-windows-restored", true);
   obs->AddObserver(sSelf, "profile-before-change", true);
   obs->AddObserver(sSelf, "xpcom-shutdown", true);
   obs->AddObserver(sSelf, "last-pb-context-exited", true);
@@ -94,6 +97,9 @@ CacheObserver::Shutdown()
 void
 CacheObserver::AttachToPreferences()
 {
+  sAutoDeleteCacheVersion = mozilla::Preferences::GetInt(
+    "browser.cache.auto_delete_cache_version", kAutoDeleteCacheVersion);
+
   mozilla::Preferences::AddUintVarCache(
     &sUseNewCache, "browser.cache.use_new_backend", kDefaultUseNewCache);
 
@@ -153,6 +159,21 @@ CacheObserver::AttachToPreferences()
   }
 }
 
+void CacheObserver::SchduleAutoDelete()
+{
+  // Auto-delete not set
+  if (sAutoDeleteCacheVersion == -1)
+    return;
+
+  // Don't autodelete the same version of the cache user has setup
+  // to use.
+  int32_t activeVersion = UseNewCache() ? 1 : 0;
+  if (sAutoDeleteCacheVersion == activeVersion)
+    return;
+
+  CacheStorageService::WipeCacheDirectory(sAutoDeleteCacheVersion);
+}
+
 // static
 bool const CacheObserver::UseNewCache()
 {
@@ -284,6 +305,11 @@ CacheObserver::Observe(nsISupports* aSubject,
     return NS_OK;
   }
 
+  if (!strcmp(aTopic, "sessionstore-windows-restored")) {
+    SchduleAutoDelete();
+    return NS_OK;
+  }
+
   if (!strcmp(aTopic, "profile-before-change")) {
     nsRefPtr<CacheStorageService> service = CacheStorageService::Self();
     if (service)
@@ -332,6 +358,7 @@ CacheObserver::Observe(nsISupports* aSubject,
     return NS_OK;
   }
 
+  MOZ_ASSERT(false, "Missing observer handler");
   return NS_OK;
 }
 

netwerk/cache2/CacheObserver.h

@@ -51,6 +51,7 @@ private:
   static CacheObserver* sSelf;
 
   void AttachToPreferences();
+  void SchduleAutoDelete();
 
   static uint32_t sUseNewCache;
   static bool sUseDiskCache;

netwerk/cache2/CacheStorageService.cpp

@@ -9,12 +9,13 @@
 
 #include "nsICacheStorageVisitor.h"
 #include "nsIObserverService.h"
-#include "nsICacheService.h" // for old cache preference
 #include "CacheStorage.h"
 #include "AppCacheStorage.h"
 #include "CacheEntry.h"
 
 #include "OldWrappers.h"
+#include "nsCacheService.h"
+#include "nsDeleteDir.h"
 
 #include "nsIFile.h"
 #include "nsIURI.h"
@@ -384,6 +385,25 @@ void CacheStorageService::DropPrivateBrowsingEntries()
     DoomStorageEntries(keys[i], true, nullptr);
 }
 
+// static
+void CacheStorageService::WipeCacheDirectory(uint32_t aVersion)
+{
+  nsCOMPtr<nsIFile> cacheDir;
+  switch (aVersion) {
+  case 0:
+    nsCacheService::GetDiskCacheDirectory(getter_AddRefs(cacheDir));
+    break;
+  case 1:
+    CacheFileIOManager::GetCacheDirectory(getter_AddRefs(cacheDir));
+    break;
+  }
+
+  if (!cacheDir)
+    return;
+
+  nsDeleteDir::DeleteDir(cacheDir, true, 30000);
+}
+
 // Helper methods
 
 // static

netwerk/cache2/CacheStorageService.h

@@ -53,6 +53,9 @@ public:
   void Shutdown();
   void DropPrivateBrowsingEntries();
 
+  // Wipes out the new or the old cache directory completely.
+  static void WipeCacheDirectory(uint32_t aVersion);
+
   static CacheStorageService* Self() { return sSelf; }
   nsresult Dispatch(nsIRunnable* aEvent);
   static bool IsRunning() { return sSelf && !sSelf->mShutdown; }

netwerk/cache2/moz.build

@@ -47,6 +47,7 @@ SOURCES += [
 
 LOCAL_INCLUDES += [
     '../base/src',
+    '../cache',
 ]
 
 FAIL_ON_WARNINGS = True