Disk cache v3 ref2

net/disk_cache/v3/block_bitmaps.cc

 // Copyright (c) 2012 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 "net/disk_cache/v3/block_bitmaps.h"
 
 #include "base/metrics/histogram.h"
+#include "base/strings/string_util.h"
+#include "base/strings/stringprintf.h"
+#include "base/threading/thread_checker.h"
 #include "base/time/time.h"
+#include "net/disk_cache/cache_util.h"
 #include "net/disk_cache/disk_format_base.h"
+#include "net/disk_cache/file_lock.h"
 #include "net/disk_cache/trace.h"
+#include "net/disk_cache/v3/backend_impl_v3.h"
 
 using base::TimeTicks;
 
 namespace disk_cache {
 
-BlockBitmaps::BlockBitmaps() {
+BlockBitmaps::BlockBitmaps(BackendImplV3* backend) : backend_(backend) {
 }
 
 BlockBitmaps::~BlockBitmaps() {
 }
 
 void BlockBitmaps::Init(const BlockFilesBitmaps& bitmaps) {
   bitmaps_ = bitmaps;
+  for (int i = 0; i < kFirstAdditionalBlockFileV3; i++)
+    empty_counts_[i] = EmptyBlocksForType(i);
 }
 
 bool BlockBitmaps::CreateBlock(FileType block_type,
                                int block_count,
                                Addr* block_address) {
   DCHECK_NE(block_type, EXTERNAL);
   DCHECK_NE(block_type, RANKINGS);
   if (block_count < 1 || block_count > kMaxNumBlocks)
     return false;
 
   int header_num = HeaderNumberForNewBlock(block_type, block_count);
   if (header_num < 0)
     return false;
 
+  int old_num_allocations = bitmaps_[header_num].MinimumAllocations();
+
   int index;
   if (!bitmaps_[header_num].CreateMapBlock(block_count, &index))
     return false;
 
   if (!index && (block_type == BLOCK_ENTRIES || block_type == BLOCK_EVICTED) &&
       !bitmaps_[header_num].CreateMapBlock(block_count, &index)) {
     // index 0 for entries is a reserved value.
     return false;
   }
 
+  // Yes, the count may be off by 1 when we start.
+  if (old_num_allocations != bitmaps_[header_num].MinimumAllocations())
+    empty_counts_[block_type]--;
+
+  if (empty_counts_[block_type] < (kNumExtraBlocks / kMaxNumBlocks) / 2)
+    backend_->GrowBlockFiles();
+
   Addr address(block_type, block_count, bitmaps_[header_num].FileId(), index);
   block_address->set_value(address.value());
   Trace("CreateBlock 0x%x", address.value());
   return true;
 }
 
 void BlockBitmaps::DeleteBlock(Addr address) {
   if (!address.is_initialized() || address.is_separate_file())
     return;
 
   int header_num = GetHeaderNumber(address);
   if (header_num < 0)
     return;
 
   Trace("DeleteBlock 0x%x", address.value());
   bitmaps_[header_num].DeleteMapBlock(address.start_block(),
                                       address.num_blocks());
+
+  //if (!bitmaps_[header_num].Header()->num_entries) {
+    // This file is now empty. Let's try to delete it.
+    //FileType type = Addr::RequiredFileType(header->entry_size);
+    //if (Addr::BlockSizeForFileType(RANKINGS) == header->entry_size)
+    //  type = RANKINGS;
+    //RemoveEmptyFile(type);  // Ignore failures.
+  //}
 }
 
 void BlockBitmaps::Clear() {
   bitmaps_.clear();
 }
 
 void BlockBitmaps::ReportStats() {
   int used_blocks[kFirstAdditionalBlockFile];
   int load[kFirstAdditionalBlockFile];
   for (int i = 0; i < kFirstAdditionalBlockFile; i++) {
@@ skipping 34 matching lines @@
   if (!address.is_initialized())
     return -1;
 
   int file_index = address.FileNumber();
   if (static_cast<unsigned int>(file_index) >= bitmaps_.size())
     return -1;
 
   return file_index;
 }
 
+int BlockBitmaps::EmptyBlocksForType(int next_file) {
+  int empty_blocks = 0;
+  do {
+    empty_blocks += bitmaps_[next_file].MinimumAllocations();
+    next_file = bitmaps_[next_file].NextFileId();
+  } while (next_file);
+  return empty_blocks;
+}
+
 int BlockBitmaps::HeaderNumberForNewBlock(FileType block_type,
                                           int block_count) {
   DCHECK_GT(block_type, 0);
   int header_num = block_type - 1;
   bool found = true;
 
   TimeTicks start = TimeTicks::Now();
   while (bitmaps_[header_num].NeedToGrowBlockFile(block_count)) {
     header_num = bitmaps_[header_num].NextFileId();
     if (!header_num) {
       found = false;
       break;
     }
   }
 
   if (!found) {
     // Restart the search, looking for any file with space. We know that all
     // files of this type are low on free blocks, but we cannot grow any file
     // at this time.
     header_num = block_type - 1;
     do {
       if (bitmaps_[header_num].CanAllocate(block_count)) {
         found = true;  // Make sure file 0 is not mistaken with a failure.
         break;
       }
       header_num = bitmaps_[header_num].NextFileId();
     } while (header_num);
 
-    if (!found)
+    if (!found) {
+      NOTREACHED();
       header_num = -1;
+    }
   }
 
   HISTOGRAM_TIMES("DiskCache.GetFileForNewBlock", TimeTicks::Now() - start);
   return header_num;
 }
 
 // We are interested in the total number of blocks used by this file type, and
 // the max number of blocks that we can store (reported as the percentage of
 // used blocks). In order to find out the number of used blocks, we have to
 // substract the empty blocks from the total blocks for each file in the chain.
@@ skipping 10 matching lines @@
     *used_count += used;
 
     index = bitmaps_[index].NextFileId();
   } while (index);
 
   if (max_blocks)
     *load = *used_count * 100 / max_blocks;
 }
 
 }  // namespace disk_cache