Disk cache: Reference CL for the implementation of file format version 3.

net/disk_cache/backend_impl.cc

Index: net/disk_cache/backend_impl.cc
===================================================================
--- net/disk_cache/backend_impl.cc	(revision 199883)
+++ net/disk_cache/backend_impl.cc	(working copy)
@@ -22,6 +22,7 @@
 #include "base/timer.h"
 #include "net/base/net_errors.h"
 #include "net/disk_cache/cache_util.h"
+#include "net/disk_cache/disk_format.h"
 #include "net/disk_cache/entry_impl.h"
 #include "net/disk_cache/errors.h"
 #include "net/disk_cache/experiments.h"
@@ -284,7 +285,7 @@
   bool previous_crash = (data_->header.crash != 0);
   data_->header.crash = 1;
 
-  if (!block_files_.Init(create_files))
+  if (!block_files_.Init(create_files, kFirstAdditionalBlockFile))
     return net::ERR_FAILED;
 
   // We want to minimize the changes to cache for an AppCache.
@@ -299,7 +300,7 @@
 
   // stats_ and rankings_ may end up calling back to us so we better be enabled.
   disabled_ = false;
-  if (!stats_.Init(this, &data_->header.stats))
+  if (!InitStats())
     return net::ERR_FAILED;
 
   disabled_ = !rankings_.Init(this, new_eviction_);
@@ -329,7 +330,7 @@
   timer_.reset();
 
   if (init_) {
-    stats_.Store();
+    StoreStats();
     if (data_)
       data_->header.crash = 0;
 
@@ -1000,8 +1001,8 @@
   disabled_ = true;
 
   if (!num_refs_)
-    MessageLoop::current()->PostTask(FROM_HERE,
-        base::Bind(&BackendImpl::RestartCache, GetWeakPtr(), true));
+    base::MessageLoop::current()->PostTask(
+        FROM_HERE, base::Bind(&BackendImpl::RestartCache, GetWeakPtr(), true));
 }
 
 void BackendImpl::ReportError(int error) {
@@ -1066,7 +1067,7 @@
 
   // Save stats to disk at 5 min intervals.
   if (time % 10 == 0)
-    stats_.Store();
+    StoreStats();
 }
 
 void BackendImpl::IncrementIoCount() {
@@ -1352,11 +1353,66 @@
     max_size_= current_max_size;
 }
 
+bool BackendImpl::InitStats() {
+  Addr address(data_->header.stats);
+  int size = stats_.StorageSize();
+
+  if (!address.is_initialized()) {
+    FileType file_type = Addr::RequiredFileType(size);
+    DCHECK_NE(file_type, EXTERNAL);
+    int num_blocks = Addr::RequiredBlocks(size, file_type);
+
+    if (!CreateBlock(file_type, num_blocks, &address))
+      return false;
+    return stats_.Init(NULL, 0, address);
+  }
+
+  if (!address.is_block_file()) {
+    NOTREACHED();
+    return false;
+  }
+
+  // Load the required data.
+  size = address.num_blocks() * address.BlockSize();
+  MappedFile* file = File(address);
+  if (!file)
+    return false;
+
+  scoped_ptr<char[]> data(new char[size]);
+  size_t offset = address.start_block() * address.BlockSize() +
+                  kBlockHeaderSize;
+  if (!file->Read(data.get(), size, offset))
+    return false;
+
+  if (!stats_.Init(data.get(), size, address))
+    return false;
+  if (cache_type_ == net::DISK_CACHE && ShouldReportAgain())
+    stats_.InitSizeHistogram();
+  return true;
+}
+
+void BackendImpl::StoreStats() {
+  int size = stats_.StorageSize();
+  scoped_ptr<char[]> data(new char[size]);
+  Addr address;
+  size = stats_.SerializeStats(data.get(), size, &address);
+  DCHECK(size);
+  if (!address.is_initialized())
+    return;
+
+  MappedFile* file = File(address);
+  if (!file)
+    return;
+
+  size_t offset = address.start_block() * address.BlockSize() +
+                  kBlockHeaderSize;
+  file->Write(data.get(), size, offset);  // ignore result.
+}
+
 void BackendImpl::RestartCache(bool failure) {
   int64 errors = stats_.GetCounter(Stats::FATAL_ERROR);
   int64 full_dooms = stats_.GetCounter(Stats::DOOM_CACHE);
   int64 partial_dooms = stats_.GetCounter(Stats::DOOM_RECENT);
-  int64 ga_evictions = stats_.GetCounter(Stats::GAJS_EVICTED);
   int64 last_report = stats_.GetCounter(Stats::LAST_REPORT);
 
   PrepareForRestart();
@@ -1376,7 +1432,6 @@
     stats_.SetCounter(Stats::FATAL_ERROR, errors);
     stats_.SetCounter(Stats::DOOM_CACHE, full_dooms);
     stats_.SetCounter(Stats::DOOM_RECENT, partial_dooms);
-    stats_.SetCounter(Stats::GAJS_EVICTED, ga_evictions);
     stats_.SetCounter(Stats::LAST_REPORT, last_report);
   }
 }
@@ -1412,7 +1467,7 @@
 
   STRESS_DCHECK(block_files_.IsValid(address));
 
-  if (!address.SanityCheckForEntry()) {
+  if (!address.SanityCheckForEntryV2()) {
     LOG(WARNING) << "Wrong entry address.";
     STRESS_NOTREACHED();
     return ERR_INVALID_ADDRESS;
@@ -1779,8 +1834,8 @@
   num_refs_--;
 
   if (!num_refs_ && disabled_)
-    MessageLoop::current()->PostTask(FROM_HERE,
-        base::Bind(&BackendImpl::RestartCache, GetWeakPtr(), true));
+    base::MessageLoop::current()->PostTask(
+        FROM_HERE, base::Bind(&BackendImpl::RestartCache, GetWeakPtr(), true));
 }
 
 void BackendImpl::IncreaseNumEntries() {
@@ -1834,12 +1889,9 @@
             static_cast<int>(stats_.GetCounter(Stats::DOOM_CACHE)));
   CACHE_UMA(COUNTS_10000, "TotalDoomRecentEntries", 0,
             static_cast<int>(stats_.GetCounter(Stats::DOOM_RECENT)));
-  CACHE_UMA(COUNTS_10000, "TotalEvictionsGaJs", 0,
-            static_cast<int>(stats_.GetCounter(Stats::GAJS_EVICTED)));
   stats_.SetCounter(Stats::FATAL_ERROR, 0);
   stats_.SetCounter(Stats::DOOM_CACHE, 0);
   stats_.SetCounter(Stats::DOOM_RECENT, 0);
-  stats_.SetCounter(Stats::GAJS_EVICTED, 0);
 
   int64 total_hours = stats_.GetCounter(Stats::TIMER) / 120;
   if (!data_->header.create_time || !data_->header.lru.filled) {