Add a Clear() function to MRUCache. This will be useful in my MemoryPurger class. Technically you can call ShrinkToSize(0), but that's both less clear and slower.

BUG=23400
TEST=none
Review URL: http://codereview.chromium.org/257024

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@27892 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 43 insertions, 6 deletions

diff --git a/chrome/browser/history/text_database_manager.cc b/chrome/browser/history/text_database_manager.cc
index 868a5d8..149cd72 100644
--- a/chrome/browser/history/text_database_manager.cc
+++ b/chrome/browser/history/text_database_manager.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
@@ -369,7 +369,7 @@ void TextDatabaseManager::DeleteAll() {
   InitDBList();
 
   // Close all open databases.
-  db_cache_.ShrinkToSize(0);
+  db_cache_.Clear();
 
   // Now go through and delete all the files.
   for (DBIdentSet::iterator i = present_databases_.begin();
diff --git a/chrome/browser/renderer_host/backing_store_manager.cc b/chrome/browser/renderer_host/backing_store_manager.cc
index 4ea7349..aeaee18 100644
--- a/chrome/browser/renderer_host/backing_store_manager.cc
+++ b/chrome/browser/renderer_host/backing_store_manager.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
@@ -217,6 +217,14 @@ void BackingStoreManager::RemoveBackingStore(RenderWidgetHost* host) {
 }
 
 // static
+void BackingStoreManager::RemoveAllBackingStores() {
+  if (large_cache) {
+    large_cache->Clear();
+    small_cache->Clear();
+  }
+}
+
+// static
 bool BackingStoreManager::ExpireBackingStoreForTest(RenderWidgetHost* host) {
   BackingStoreCache* cache = large_cache;
 
diff --git a/chrome/browser/renderer_host/backing_store_manager.h b/chrome/browser/renderer_host/backing_store_manager.h
index 625e87f..8344ca2 100644
--- a/chrome/browser/renderer_host/backing_store_manager.h
+++ b/chrome/browser/renderer_host/backing_store_manager.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
@@ -58,6 +58,9 @@ class BackingStoreManager {
   // Removes the backing store for the host.
   static void RemoveBackingStore(RenderWidgetHost* host);
 
+  // Removes all backing stores.
+  static void RemoveAllBackingStores();
+
   // Expires the given backing store. This emulates something getting evicted
   // from the cache for the purpose of testing. Returns true if the host was
   // removed, false if it wasn't found.
diff --git a/chrome/common/mru_cache.h b/chrome/common/mru_cache.h
index 02e7242..9190d9d 100644
--- a/chrome/common/mru_cache.h
+++ b/chrome/common/mru_cache.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
@@ -137,6 +137,15 @@ class MRUCacheBase {
       Erase(rbegin());
   }
 
+  // Deletes everything from the cache.
+  void Clear() {
+    for (typename PayloadList::iterator i(ordering_.begin());
+         i != ordering_.end(); ++i)
+      deletor_(i->second);
+    index_.clear();
+    ordering_.clear();
+  }
+
   // Returns the number of elements in the cache.
   size_type size() const {
     // We don't use ordering_.size() for the return value because
diff --git a/chrome/common/mru_cache_unittest.cc b/chrome/common/mru_cache_unittest.cc
index 15f3dc5..bacb8a5 100644
--- a/chrome/common/mru_cache_unittest.cc
+++ b/chrome/common/mru_cache_unittest.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
@@ -103,6 +103,13 @@ TEST(MRUCacheTest, Basic) {
     cache.Erase(cache.begin());
     EXPECT_EQ(0U, cache.size());
   }
+
+  // Check that Clear() works properly.
+  cache.Put(kItem1Key, item1);
+  cache.Put(kItem2Key, item2);
+  EXPECT_EQ(2U, cache.size());
+  cache.Clear();
+  EXPECT_EQ(0U, cache.size());
 }
 
 TEST(MRUCacheTest, GetVsPeek) {
@@ -209,6 +216,16 @@ TEST(MRUCacheTest, Owning) {
 
   // There should be no objects leaked.
   EXPECT_EQ(initial_count, cached_item_live_count);
+
+  // Check that Clear() also frees things correctly.
+  {
+    Cache cache2(Cache::NO_AUTO_EVICT);
+    cache2.Put(1, new CachedItem(20));
+    cache2.Put(2, new CachedItem(20));
+    EXPECT_EQ(initial_count + 2, cached_item_live_count);
+    cache2.Clear();
+    EXPECT_EQ(initial_count, cached_item_live_count);
+  }
 }
 
 TEST(MRUCacheTest, AutoEvict) {