Reorganize net/disk_cache into backend specific directories.

net/disk_cache/eviction.cc

Index: net/disk_cache/eviction.cc
diff --git a/net/disk_cache/eviction.cc b/net/disk_cache/eviction.cc
deleted file mode 100644
index 47b52552ef5c4000282bd6a7dcd1f8a82396f664..0000000000000000000000000000000000000000
--- a/net/disk_cache/eviction.cc
+++ /dev/null
@@ -1,597 +0,0 @@
-// 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.
-
-// The eviction policy is a very simple pure LRU, so the elements at the end of
-// the list are evicted until kCleanUpMargin free space is available. There is
-// only one list in use (Rankings::NO_USE), and elements are sent to the front
-// of the list whenever they are accessed.
-
-// The new (in-development) eviction policy adds re-use as a factor to evict
-// an entry. The story so far:
-
-// Entries are linked on separate lists depending on how often they are used.
-// When we see an element for the first time, it goes to the NO_USE list; if
-// the object is reused later on, we move it to the LOW_USE list, until it is
-// used kHighUse times, at which point it is moved to the HIGH_USE list.
-// Whenever an element is evicted, we move it to the DELETED list so that if the
-// element is accessed again, we remember the fact that it was already stored
-// and maybe in the future we don't evict that element.
-
-// When we have to evict an element, first we try to use the last element from
-// the NO_USE list, then we move to the LOW_USE and only then we evict an entry
-// from the HIGH_USE. We attempt to keep entries on the cache for at least
-// kTargetTime hours (with frequently accessed items stored for longer periods),
-// but if we cannot do that, we fall-back to keep each list roughly the same
-// size so that we have a chance to see an element again and move it to another
-// list.
-
-#include "net/disk_cache/eviction.h"
-
-#include "base/bind.h"
-#include "base/compiler_specific.h"
-#include "base/logging.h"
-#include "base/message_loop/message_loop.h"
-#include "base/strings/string_util.h"
-#include "base/time/time.h"
-#include "net/disk_cache/backend_impl.h"
-#include "net/disk_cache/disk_format.h"
-#include "net/disk_cache/entry_impl.h"
-#include "net/disk_cache/experiments.h"
-#include "net/disk_cache/histogram_macros.h"
-#include "net/disk_cache/trace.h"
-
-using base::Time;
-using base::TimeTicks;
-
-namespace {
-
-const int kCleanUpMargin = 1024 * 1024;
-const int kHighUse = 10;  // Reuse count to be on the HIGH_USE list.
-const int kTargetTime = 24 * 7;  // Time to be evicted (hours since last use).
-const int kMaxDelayedTrims = 60;
-
-int LowWaterAdjust(int high_water) {
-  if (high_water < kCleanUpMargin)
-    return 0;
-
-  return high_water - kCleanUpMargin;
-}
-
-bool FallingBehind(int current_size, int max_size) {
-  return current_size > max_size - kCleanUpMargin * 20;
-}
-
-}  // namespace
-
-namespace disk_cache {
-
-// The real initialization happens during Init(), init_ is the only member that
-// has to be initialized here.
-Eviction::Eviction()
-    : backend_(NULL),
-      init_(false),
-      ptr_factory_(this) {
-}
-
-Eviction::~Eviction() {
-}
-
-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_);
-  index_size_ = backend->mask_ + 1;
-  new_eviction_ = backend->new_eviction_;
-  first_trim_ = true;
-  trimming_ = false;
-  delay_trim_ = false;
-  trim_delays_ = 0;
-  init_ = true;
-  test_mode_ = false;
-}
-
-void Eviction::Stop() {
-  // It is possible for the backend initialization to fail, in which case this
-  // object was never initialized... and there is nothing to do.
-  if (!init_)
-    return;
-
-  // We want to stop further evictions, so let's pretend that we are busy from
-  // this point on.
-  DCHECK(!trimming_);
-  trimming_ = true;
-  ptr_factory_.InvalidateWeakPtrs();
-}
-
-void Eviction::TrimCache(bool empty) {
-  if (backend_->disabled_ || trimming_)
-    return;
-
-  if (!empty && !ShouldTrim())
-    return PostDelayedTrim();
-
-  if (new_eviction_)
-    return TrimCacheV2(empty);
-
-  Trace("*** Trim Cache ***");
-  trimming_ = true;
-  TimeTicks start = TimeTicks::Now();
-  Rankings::ScopedRankingsBlock node(rankings_);
-  Rankings::ScopedRankingsBlock next(
-      rankings_, rankings_->GetPrev(node.get(), Rankings::NO_USE));
-  int deleted_entries = 0;
-  int target_size = empty ? 0 : max_size_;
-  while ((header_->num_bytes > target_size || test_mode_) && next.get()) {
-    // The iterator could be invalidated within EvictEntry().
-    if (!next->HasData())
-      break;
-    node.reset(next.release());
-    next.reset(rankings_->GetPrev(node.get(), Rankings::NO_USE));
-    if (node->Data()->dirty != backend_->GetCurrentEntryId() || empty) {
-      // This entry is not being used by anybody.
-      // Do NOT use node as an iterator after this point.
-      rankings_->TrackRankingsBlock(node.get(), false);
-      if (EvictEntry(node.get(), empty, Rankings::NO_USE) && !test_mode_)
-        deleted_entries++;
-
-      if (!empty && test_mode_)
-        break;
-    }
-    if (!empty && (deleted_entries > 20 ||
-                   (TimeTicks::Now() - start).InMilliseconds() > 20)) {
-      base::MessageLoop::current()->PostTask(
-          FROM_HERE,
-          base::Bind(&Eviction::TrimCache, ptr_factory_.GetWeakPtr(), false));
-      break;
-    }
-  }
-
-  if (empty) {
-    CACHE_UMA(AGE_MS, "TotalClearTimeV1", 0, start);
-  } else {
-    CACHE_UMA(AGE_MS, "TotalTrimTimeV1", 0, start);
-  }
-  CACHE_UMA(COUNTS, "TrimItemsV1", 0, deleted_entries);
-
-  trimming_ = false;
-  Trace("*** Trim Cache end ***");
-  return;
-}
-
-void Eviction::UpdateRank(EntryImpl* entry, bool modified) {
-  if (new_eviction_)
-    return UpdateRankV2(entry, modified);
-
-  rankings_->UpdateRank(entry->rankings(), modified, GetListForEntry(entry));
-}
-
-void Eviction::OnOpenEntry(EntryImpl* entry) {
-  if (new_eviction_)
-    return OnOpenEntryV2(entry);
-}
-
-void Eviction::OnCreateEntry(EntryImpl* entry) {
-  if (new_eviction_)
-    return OnCreateEntryV2(entry);
-
-  rankings_->Insert(entry->rankings(), true, GetListForEntry(entry));
-}
-
-void Eviction::OnDoomEntry(EntryImpl* entry) {
-  if (new_eviction_)
-    return OnDoomEntryV2(entry);
-
-  if (entry->LeaveRankingsBehind())
-    return;
-
-  rankings_->Remove(entry->rankings(), GetListForEntry(entry), true);
-}
-
-void Eviction::OnDestroyEntry(EntryImpl* entry) {
-  if (new_eviction_)
-    return OnDestroyEntryV2(entry);
-}
-
-void Eviction::SetTestMode() {
-  test_mode_ = true;
-}
-
-void Eviction::TrimDeletedList(bool empty) {
-  DCHECK(test_mode_ && new_eviction_);
-  TrimDeleted(empty);
-}
-
-void Eviction::PostDelayedTrim() {
-  // Prevent posting multiple tasks.
-  if (delay_trim_)
-    return;
-  delay_trim_ = true;
-  trim_delays_++;
-  base::MessageLoop::current()->PostDelayedTask(
-      FROM_HERE,
-      base::Bind(&Eviction::DelayedTrim, ptr_factory_.GetWeakPtr()),
-      base::TimeDelta::FromMilliseconds(1000));
-}
-
-void Eviction::DelayedTrim() {
-  delay_trim_ = false;
-  if (trim_delays_ < kMaxDelayedTrims && backend_->IsLoaded())
-    return PostDelayedTrim();
-
-  TrimCache(false);
-}
-
-bool Eviction::ShouldTrim() {
-  if (!FallingBehind(header_->num_bytes, max_size_) &&
-      trim_delays_ < kMaxDelayedTrims && backend_->IsLoaded()) {
-    return false;
-  }
-
-  UMA_HISTOGRAM_COUNTS("DiskCache.TrimDelays", trim_delays_);
-  trim_delays_ = 0;
-  return true;
-}
-
-bool Eviction::ShouldTrimDeleted() {
-  int index_load = header_->num_entries * 100 / index_size_;
-
-  // If the index is not loaded, the deleted list will tend to double the size
-  // of the other lists 3 lists (40% of the total). Otherwise, all lists will be
-  // about the same size.
-  int max_length = (index_load < 25) ? header_->num_entries * 2 / 5 :
-                                       header_->num_entries / 4;
-  return (!test_mode_ && header_->lru.sizes[Rankings::DELETED] > max_length);
-}
-
-void Eviction::ReportTrimTimes(EntryImpl* entry) {
-  if (first_trim_) {
-    first_trim_ = false;
-    if (backend_->ShouldReportAgain()) {
-      CACHE_UMA(AGE, "TrimAge", 0, entry->GetLastUsed());
-      ReportListStats();
-    }
-
-    if (header_->lru.filled)
-      return;
-
-    header_->lru.filled = 1;
-
-    if (header_->create_time) {
-      // This is the first entry that we have to evict, generate some noise.
-      backend_->FirstEviction();
-    } else {
-      // This is an old file, but we may want more reports from this user so
-      // lets save some create_time.
-      Time::Exploded old = {0};
-      old.year = 2009;
-      old.month = 3;
-      old.day_of_month = 1;
-      header_->create_time = Time::FromLocalExploded(old).ToInternalValue();
-    }
-  }
-}
-
-Rankings::List Eviction::GetListForEntry(EntryImpl* entry) {
-  return Rankings::NO_USE;
-}
-
-bool Eviction::EvictEntry(CacheRankingsBlock* node, bool empty,
-                          Rankings::List list) {
-  EntryImpl* entry = backend_->GetEnumeratedEntry(node, list);
-  if (!entry) {
-    Trace("NewEntry failed on Trim 0x%x", node->address().value());
-    return false;
-  }
-
-  ReportTrimTimes(entry);
-  if (empty || !new_eviction_) {
-    entry->DoomImpl();
-  } else {
-    entry->DeleteEntryData(false);
-    EntryStore* info = entry->entry()->Data();
-    DCHECK_EQ(ENTRY_NORMAL, info->state);
-
-    rankings_->Remove(entry->rankings(), GetListForEntryV2(entry), true);
-    info->state = ENTRY_EVICTED;
-    entry->entry()->Store();
-    rankings_->Insert(entry->rankings(), true, Rankings::DELETED);
-  }
-  if (!empty)
-    backend_->OnEvent(Stats::TRIM_ENTRY);
-
-  entry->Release();
-
-  return true;
-}
-
-// -----------------------------------------------------------------------
-
-void Eviction::TrimCacheV2(bool empty) {
-  Trace("*** Trim Cache ***");
-  trimming_ = true;
-  TimeTicks start = TimeTicks::Now();
-
-  const int kListsToSearch = 3;
-  Rankings::ScopedRankingsBlock next[kListsToSearch];
-  int list = Rankings::LAST_ELEMENT;
-
-  // Get a node from each list.
-  for (int i = 0; i < kListsToSearch; i++) {
-    bool done = false;
-    next[i].set_rankings(rankings_);
-    if (done)
-      continue;
-    next[i].reset(rankings_->GetPrev(NULL, static_cast<Rankings::List>(i)));
-    if (!empty && NodeIsOldEnough(next[i].get(), i)) {
-      list = static_cast<Rankings::List>(i);
-      done = true;
-    }
-  }
-
-  // If we are not meeting the time targets lets move on to list length.
-  if (!empty && Rankings::LAST_ELEMENT == list)
-    list = SelectListByLength(next);
-
-  if (empty)
-    list = 0;
-
-  Rankings::ScopedRankingsBlock node(rankings_);
-  int deleted_entries = 0;
-  int target_size = empty ? 0 : max_size_;
-
-  for (; list < kListsToSearch; list++) {
-    while ((header_->num_bytes > target_size || test_mode_) &&
-           next[list].get()) {
-      // The iterator could be invalidated within EvictEntry().
-      if (!next[list]->HasData())
-        break;
-      node.reset(next[list].release());
-      next[list].reset(rankings_->GetPrev(node.get(),
-                                          static_cast<Rankings::List>(list)));
-      if (node->Data()->dirty != backend_->GetCurrentEntryId() || empty) {
-        // This entry is not being used by anybody.
-        // Do NOT use node as an iterator after this point.
-        rankings_->TrackRankingsBlock(node.get(), false);
-        if (EvictEntry(node.get(), empty, static_cast<Rankings::List>(list)))
-          deleted_entries++;
-
-        if (!empty && test_mode_)
-          break;
-      }
-      if (!empty && (deleted_entries > 20 ||
-                     (TimeTicks::Now() - start).InMilliseconds() > 20)) {
-        base::MessageLoop::current()->PostTask(
-            FROM_HERE,
-            base::Bind(&Eviction::TrimCache, ptr_factory_.GetWeakPtr(), false));
-        break;
-      }
-    }
-    if (!empty)
-      list = kListsToSearch;
-  }
-
-  if (empty) {
-    TrimDeleted(true);
-  } else if (ShouldTrimDeleted()) {
-    base::MessageLoop::current()->PostTask(
-        FROM_HERE,
-        base::Bind(&Eviction::TrimDeleted, ptr_factory_.GetWeakPtr(), empty));
-  }
-
-  if (empty) {
-    CACHE_UMA(AGE_MS, "TotalClearTimeV2", 0, start);
-  } else {
-    CACHE_UMA(AGE_MS, "TotalTrimTimeV2", 0, start);
-  }
-  CACHE_UMA(COUNTS, "TrimItemsV2", 0, deleted_entries);
-
-  Trace("*** Trim Cache end ***");
-  trimming_ = false;
-  return;
-}
-
-void Eviction::UpdateRankV2(EntryImpl* entry, bool modified) {
-  rankings_->UpdateRank(entry->rankings(), modified, GetListForEntryV2(entry));
-}
-
-void Eviction::OnOpenEntryV2(EntryImpl* entry) {
-  EntryStore* info = entry->entry()->Data();
-  DCHECK_EQ(ENTRY_NORMAL, info->state);
-
-  if (info->reuse_count < kint32max) {
-    info->reuse_count++;
-    entry->entry()->set_modified();
-
-    // We may need to move this to a new list.
-    if (1 == info->reuse_count) {
-      rankings_->Remove(entry->rankings(), Rankings::NO_USE, true);
-      rankings_->Insert(entry->rankings(), false, Rankings::LOW_USE);
-      entry->entry()->Store();
-    } else if (kHighUse == info->reuse_count) {
-      rankings_->Remove(entry->rankings(), Rankings::LOW_USE, true);
-      rankings_->Insert(entry->rankings(), false, Rankings::HIGH_USE);
-      entry->entry()->Store();
-    }
-  }
-}
-
-void Eviction::OnCreateEntryV2(EntryImpl* entry) {
-  EntryStore* info = entry->entry()->Data();
-  switch (info->state) {
-    case ENTRY_NORMAL: {
-      DCHECK(!info->reuse_count);
-      DCHECK(!info->refetch_count);
-      break;
-    };
-    case ENTRY_EVICTED: {
-      if (info->refetch_count < kint32max)
-        info->refetch_count++;
-
-      if (info->refetch_count > kHighUse && info->reuse_count < kHighUse) {
-        info->reuse_count = kHighUse;
-      } else {
-        info->reuse_count++;
-      }
-      info->state = ENTRY_NORMAL;
-      entry->entry()->Store();
-      rankings_->Remove(entry->rankings(), Rankings::DELETED, true);
-      break;
-    };
-    default:
-      NOTREACHED();
-  }
-
-  rankings_->Insert(entry->rankings(), true, GetListForEntryV2(entry));
-}
-
-void Eviction::OnDoomEntryV2(EntryImpl* entry) {
-  EntryStore* info = entry->entry()->Data();
-  if (ENTRY_NORMAL != info->state)
-    return;
-
-  if (entry->LeaveRankingsBehind()) {
-    info->state = ENTRY_DOOMED;
-    entry->entry()->Store();
-    return;
-  }
-
-  rankings_->Remove(entry->rankings(), GetListForEntryV2(entry), true);
-
-  info->state = ENTRY_DOOMED;
-  entry->entry()->Store();
-  rankings_->Insert(entry->rankings(), true, Rankings::DELETED);
-}
-
-void Eviction::OnDestroyEntryV2(EntryImpl* entry) {
-  if (entry->LeaveRankingsBehind())
-    return;
-
-  rankings_->Remove(entry->rankings(), Rankings::DELETED, true);
-}
-
-Rankings::List Eviction::GetListForEntryV2(EntryImpl* entry) {
-  EntryStore* info = entry->entry()->Data();
-  DCHECK_EQ(ENTRY_NORMAL, info->state);
-
-  if (!info->reuse_count)
-    return Rankings::NO_USE;
-
-  if (info->reuse_count < kHighUse)
-    return Rankings::LOW_USE;
-
-  return Rankings::HIGH_USE;
-}
-
-// This is a minimal implementation that just discards the oldest nodes.
-// TODO(rvargas): Do something better here.
-void Eviction::TrimDeleted(bool empty) {
-  Trace("*** Trim Deleted ***");
-  if (backend_->disabled_)
-    return;
-
-  TimeTicks start = TimeTicks::Now();
-  Rankings::ScopedRankingsBlock node(rankings_);
-  Rankings::ScopedRankingsBlock next(
-    rankings_, rankings_->GetPrev(node.get(), Rankings::DELETED));
-  int deleted_entries = 0;
-  while (next.get() &&
-         (empty || (deleted_entries < 20 &&
-                    (TimeTicks::Now() - start).InMilliseconds() < 20))) {
-    node.reset(next.release());
-    next.reset(rankings_->GetPrev(node.get(), Rankings::DELETED));
-    if (RemoveDeletedNode(node.get()))
-      deleted_entries++;
-    if (test_mode_)
-      break;
-  }
-
-  if (deleted_entries && !empty && ShouldTrimDeleted()) {
-    base::MessageLoop::current()->PostTask(
-        FROM_HERE,
-        base::Bind(&Eviction::TrimDeleted, ptr_factory_.GetWeakPtr(), false));
-  }
-
-  CACHE_UMA(AGE_MS, "TotalTrimDeletedTime", 0, start);
-  CACHE_UMA(COUNTS, "TrimDeletedItems", 0, deleted_entries);
-  Trace("*** Trim Deleted end ***");
-  return;
-}
-
-bool Eviction::RemoveDeletedNode(CacheRankingsBlock* node) {
-  EntryImpl* entry = backend_->GetEnumeratedEntry(node, Rankings::DELETED);
-  if (!entry) {
-    Trace("NewEntry failed on Trim 0x%x", node->address().value());
-    return false;
-  }
-
-  bool doomed = (entry->entry()->Data()->state == ENTRY_DOOMED);
-  entry->entry()->Data()->state = ENTRY_DOOMED;
-  entry->DoomImpl();
-  entry->Release();
-  return !doomed;
-}
-
-bool Eviction::NodeIsOldEnough(CacheRankingsBlock* node, int list) {
-  if (!node)
-    return false;
-
-  // If possible, we want to keep entries on each list at least kTargetTime
-  // hours. Each successive list on the enumeration has 2x the target time of
-  // the previous list.
-  Time used = Time::FromInternalValue(node->Data()->last_used);
-  int multiplier = 1 << list;
-  return (Time::Now() - used).InHours() > kTargetTime * multiplier;
-}
-
-int Eviction::SelectListByLength(Rankings::ScopedRankingsBlock* next) {
-  int data_entries = header_->num_entries -
-                     header_->lru.sizes[Rankings::DELETED];
-  // Start by having each list to be roughly the same size.
-  if (header_->lru.sizes[0] > data_entries / 3)
-    return 0;
-
-  int list = (header_->lru.sizes[1] > data_entries / 3) ? 1 : 2;
-
-  // Make sure that frequently used items are kept for a minimum time; we know
-  // that this entry is not older than its current target, but it must be at
-  // least older than the target for list 0 (kTargetTime), as long as we don't
-  // exhaust list 0.
-  if (!NodeIsOldEnough(next[list].get(), 0) &&
-      header_->lru.sizes[0] > data_entries / 10)
-    list = 0;
-
-  return list;
-}
-
-void Eviction::ReportListStats() {
-  if (!new_eviction_)
-    return;
-
-  Rankings::ScopedRankingsBlock last1(rankings_,
-      rankings_->GetPrev(NULL, Rankings::NO_USE));
-  Rankings::ScopedRankingsBlock last2(rankings_,
-      rankings_->GetPrev(NULL, Rankings::LOW_USE));
-  Rankings::ScopedRankingsBlock last3(rankings_,
-      rankings_->GetPrev(NULL, Rankings::HIGH_USE));
-  Rankings::ScopedRankingsBlock last4(rankings_,
-      rankings_->GetPrev(NULL, Rankings::DELETED));
-
-  if (last1.get())
-    CACHE_UMA(AGE, "NoUseAge", 0,
-              Time::FromInternalValue(last1.get()->Data()->last_used));
-  if (last2.get())
-    CACHE_UMA(AGE, "LowUseAge", 0,
-              Time::FromInternalValue(last2.get()->Data()->last_used));
-  if (last3.get())
-    CACHE_UMA(AGE, "HighUseAge", 0,
-              Time::FromInternalValue(last3.get()->Data()->last_used));
-  if (last4.get())
-    CACHE_UMA(AGE, "DeletedAge", 0,
-              Time::FromInternalValue(last4.get()->Data()->last_used));
-}
-
-}  // namespace disk_cache