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

net/disk_cache/block_files_unittest.cc

Index: net/disk_cache/block_files_unittest.cc
===================================================================
--- net/disk_cache/block_files_unittest.cc	(revision 21550)
+++ net/disk_cache/block_files_unittest.cc	(working copy)
@@ -11,6 +11,21 @@
 
 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()));
@@ -19,13 +34,48 @@
   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();