Disk cache: move eviction code to a separate file.

There should be no change in behavior with this CL.

Review URL: http://codereview.chromium.org/14183

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@7190 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 122 insertions, 0 deletions

diff --git a/net/disk_cache/eviction.cc b/net/disk_cache/eviction.cc
new file mode 100644
index 0000000..11ff969
--- /dev/null
+++ b/net/disk_cache/eviction.cc
@@ -0,0 +1,122 @@
+// 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/eviction.h"
+
+#include "base/logging.h"
+#include "base/message_loop.h"
+#include "base/string_util.h"
+#include "base/time.h"
+#include "net/disk_cache/backend_impl.h"
+#include "net/disk_cache/entry_impl.h"
+#include "net/disk_cache/trace.h"
+
+using base::Time;
+
+namespace {
+
+const int kCleanUpMargin = 1024 * 1024;
+
+int LowWaterAdjust(int high_water) {
+  if (high_water < kCleanUpMargin)
+    return 0;
+
+  return high_water - kCleanUpMargin;
+}
+
+}  // namespace
+
+namespace disk_cache {
+
+void Eviction::Init(BackendImpl* backend) {
+  // We grab a bunch of info from the backend to make the code a little cleaner
+  // when we're actually doing work.
+  backend_ = backend;
+  rankings_ = &backend->rankings_;
+  header_ = &backend_->data_->header;
+  max_size_ = LowWaterAdjust(backend_->max_size_);
+}
+
+void Eviction::TrimCache(bool empty) {
+  Trace("*** Trim Cache ***");
+  if (backend_->disabled_)
+    return;
+
+  Time start = Time::Now();
+  Rankings::ScopedRankingsBlock node(rankings_);
+  Rankings::ScopedRankingsBlock next(rankings_,
+      rankings_->GetPrev(node.get(), Rankings::NO_USE));
+  DCHECK(next.get());
+  int target_size = empty ? 0 : max_size_;
+  int deleted = 0;
+  while (header_->num_bytes > target_size && next.get()) {
+    node.reset(next.release());
+    next.reset(rankings_->GetPrev(node.get(), Rankings::NO_USE));
+    if (!node->Data()->pointer || empty) {
+      // This entry is not being used by anybody.
+      EntryImpl* entry;
+      bool dirty;
+      if (backend_->NewEntry(Addr(node->Data()->contents), &entry, &dirty)) {
+        Trace("NewEntry failed on Trim 0x%x", node->address().value());
+        continue;
+      }
+
+      if (node->Data()->pointer) {
+        entry = EntryImpl::Update(entry);
+      }
+      ReportTrimTimes(entry);
+      entry->Doom();
+      entry->Release();
+      if (!empty)
+        backend_->OnEvent(Stats::TRIM_ENTRY);
+      if (++deleted == 4 && !empty) {
+#if defined(OS_WIN)
+        MessageLoop::current()->PostTask(FROM_HERE,
+            factory_.NewRunnableMethod(&Eviction::TrimCache, false));
+        break;
+#endif
+      }
+    }
+  }
+
+  UMA_HISTOGRAM_TIMES(L"DiskCache.TotalTrimTime", Time::Now() - start);
+  Trace("*** Trim Cache end ***");
+  return;
+}
+
+void Eviction::UpdateRank(EntryImpl* entry, bool modified) {
+  rankings_->UpdateRank(entry->rankings(), modified, GetListForEntry(entry));
+}
+
+void Eviction::OnOpenEntry(EntryImpl* entry) {
+}
+
+void Eviction::OnCreateEntry(EntryImpl* entry) {
+  rankings_->Insert(entry->rankings(), true, GetListForEntry(entry));
+}
+
+void Eviction::OnDoomEntry(EntryImpl* entry) {
+  rankings_->Remove(entry->rankings(), GetListForEntry(entry));
+}
+
+void Eviction::OnDestroyEntry(EntryImpl* entry) {
+}
+
+void Eviction::ReportTrimTimes(EntryImpl* entry) {
+  static bool first_time = true;
+  if (first_time) {
+    first_time = false;
+    std::wstring name(StringPrintf(L"DiskCache.TrimAge_%d",
+                                   header_->experiment));
+    static Histogram counter(name.c_str(), 1, 10000, 50);
+    counter.SetFlags(kUmaTargetedHistogramFlag);
+    counter.Add((Time::Now() - entry->GetLastUsed()).InHours());
+  }
+}
+
+Rankings::List Eviction::GetListForEntry(EntryImpl* entry) {
+  return Rankings::NO_USE;
+}
+
+}  // namespace disk_cache