Disk cache: Open the disk cache experiment for new users....

net/disk_cache/backend_impl.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 "net/disk_cache/backend_impl.h"
 
 #include "base/field_trial.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/histogram.h"
@@ skipping 129 matching lines @@
 
 // Sets |current_group| for the current experiment. Returns false if the files
 // should be discarded.
 bool InitExperiment(int* current_group) {
   if (*current_group == 3 || *current_group == 4) {
     // Discard current cache for groups 3 and 4.
     return false;
   }
 
   if (*current_group <= 5) {
-#if defined(UNIT_TEST)
-    // The unit test controls directly what to test.
-    *current_group = 0;
-    return true;
-#endif
-
     // Re-load the two groups.
     int option = base::RandInt(0, 9);
 
     if (option > 1) {
       // 80% will be out of the experiment.
       *current_group = 9;
     } else {
       *current_group = option + 6;
     }
   }
@@ skipping 121 matching lines @@
 
   if (!restarted_) {
     trace_object_ = TraceObject::GetTraceObject();
     // Create a recurrent timer of 30 secs.
     int timer_delay = unit_test_ ? 1000 : 30000;
     timer_.Start(TimeDelta::FromMilliseconds(timer_delay), this,
                  &BackendImpl::OnStatsTimer);
   }
 
   init_ = true;
-  if (!InitExperiment(&data_->header.experiment))
-    return false;
+  if (!(user_flags_ & disk_cache::kNoRandom)) {
+    // The unit test controls directly what to test.
+    if (!InitExperiment(&data_->header.experiment))
+      return false;
+  }
 
   if (data_->header.experiment > 6 && data_->header.experiment < 9)
     new_eviction_ = true;
 
   if (!CheckIndex()) {
     ReportError(ERR_INIT_FAILED);
     return false;
   }
 
   // We don't care if the value overflows. The only thing we care about is that
@@ skipping 633 matching lines @@
 void BackendImpl::SetUpgradeMode() {
   user_flags_ |= kUpgradeMode;
   read_only_ = true;
 }
 
 void BackendImpl::SetNewEviction() {
   user_flags_ |= kNewEviction;
   new_eviction_ = true;
 }
 
+void BackendImpl::SetFlags(uint32 flags) {
+  user_flags_ |= flags;
+}
+
 void BackendImpl::ClearRefCountForTest() {
   num_refs_ = 0;
 }
 
 int BackendImpl::SelfCheck() {
   if (!init_) {
     LOG(ERROR) << "Init failed";
     return ERR_INIT_FAILED;
   }
 
@@ skipping 18 matching lines @@
 // ------------------------------------------------------------------------
 
 // We just created a new file so we're going to write the header and set the
 // file length to include the hash table (zero filled).
 bool BackendImpl::CreateBackingStore(disk_cache::File* file) {
   AdjustMaxCacheSize(0);
 
   IndexHeader header;
   header.table_len = DesiredIndexTableLen(max_size_);
 
+  // All new profiles are going to use the new eviction.
+  if (!(user_flags_ & disk_cache::kNoRandom)) {
+    header.experiment = 8;
+    new_eviction_ = true;
+  }
+
   // We need file version 2.1 for the new eviction algorithm.
   if (new_eviction_)
     header.version = 0x20001;
 
   header.create_time = Time::Now().ToInternalValue();
 
   if (!file->Write(&header, sizeof(header), 0))
     return false;
 
   return file->SetLength(GetIndexSize(header.table_len));
@@ skipping 638 matching lines @@
 
   return num_dirty;
 }
 
 bool BackendImpl::CheckEntry(EntryImpl* cache_entry) {
   RankingsNode* rankings = cache_entry->rankings()->Data();
   return !rankings->dummy;
 }
 
 }  // namespace disk_cache