Disk Cache: Delete chained block files when they become empty....

net/disk_cache/block_files_unittest.cc

 // Copyright (c) 2006-2008 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.
 
 #include "base/file_util.h"
 #include "net/disk_cache/block_files.h"
 #include "net/disk_cache/disk_cache.h"
 #include "net/disk_cache/disk_cache_test_base.h"
 #include "net/disk_cache/disk_cache_test_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using base::Time;
 
+namespace {
+
+// Returns the number of files in this folder.
+int NumberOfFiles(const std::wstring path) {
+  file_util::FileEnumerator iter(FilePath::FromWStringHack(path), false,
+                                 file_util::FileEnumerator::FILES);
+  int count = 0;
+  for (FilePath file = iter.Next(); !file.value().empty(); file = iter.Next()) {
+    count++;
+  }
+  return count;
+}
+
+}  // namespace;
+
 TEST_F(DiskCacheTest, BlockFiles_Grow) {
   std::wstring path = GetCachePath();
   ASSERT_TRUE(DeleteCache(path.c_str()));
   ASSERT_TRUE(file_util::CreateDirectory(path));
 
   disk_cache::BlockFiles files(path);
   ASSERT_TRUE(files.Init(true));
 
+  const int kMaxSize = 35000;
+  disk_cache::Addr address[kMaxSize];
+
   // Fill up the 32-byte block file (use three files).
-  for (int i = 0; i < 35000; i++) {
-    disk_cache::Addr address(0);
-    EXPECT_TRUE(files.CreateBlock(disk_cache::RANKINGS, 4, &address));
+  for (int i = 0; i < kMaxSize; i++) {
+    EXPECT_TRUE(files.CreateBlock(disk_cache::RANKINGS, 4, &address[i]));
   }
+  EXPECT_EQ(6, NumberOfFiles(path));
+
+  // Make sure we don't keep adding files.
+  for (int i = 0; i < kMaxSize * 4; i += 2) {
+    int target = i % kMaxSize;
+    files.DeleteBlock(address[target], false);
+    EXPECT_TRUE(files.CreateBlock(disk_cache::RANKINGS, 4, &address[target]));
+  }
+  EXPECT_EQ(6, NumberOfFiles(path));
+}
+
+// We should be able to delete empty block files.
+TEST_F(DiskCacheTest, BlockFiles_Shrink) {
+  std::wstring path = GetCachePath();
+  ASSERT_TRUE(DeleteCache(path.c_str()));
+  ASSERT_TRUE(file_util::CreateDirectory(path));
+
+  disk_cache::BlockFiles files(path);
+  ASSERT_TRUE(files.Init(true));
+
+  const int kMaxSize = 35000;
+  disk_cache::Addr address[kMaxSize];
+
+  // Fill up the 32-byte block file (use three files).
+  for (int i = 0; i < kMaxSize; i++) {
+    EXPECT_TRUE(files.CreateBlock(disk_cache::RANKINGS, 4, &address[i]));
+  }
+
+  // Now delete all the blocks, so that we can delete the two extra files.
+  for (int i = 0; i < kMaxSize; i++) {
+    files.DeleteBlock(address[i], false);
+  }
+  EXPECT_EQ(4, NumberOfFiles(path));
 }
 
 // Handling of block files not properly closed.
 TEST_F(DiskCacheTest, BlockFiles_Recover) {
   std::wstring path = GetCachePath();
   ASSERT_TRUE(DeleteCache(path.c_str()));
   ASSERT_TRUE(file_util::CreateDirectory(path));
 
   disk_cache::BlockFiles files(path);
   ASSERT_TRUE(files.Init(true));
@@ skipping 59 matching lines @@
   ASSERT_TRUE(NULL != header);
 
   ASSERT_EQ(0, header->updating);
 
   EXPECT_EQ(max_entries, header->max_entries);
   EXPECT_EQ(empty_1, header->empty[0]);
   EXPECT_EQ(empty_2, header->empty[1]);
   EXPECT_EQ(empty_3, header->empty[2]);
   EXPECT_EQ(empty_4, header->empty[3]);
 }