Index: net/disk_cache/v3/index_table.cc |
=================================================================== |
--- net/disk_cache/v3/index_table.cc (revision 0) |
+++ net/disk_cache/v3/index_table.cc (revision 0) |
@@ -0,0 +1,717 @@ |
+// Copyright (c) 2013 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/index_table.h" |
+ |
+#include <set> |
+ |
+#include "net/base/net_errors.h" |
+#include "net/disk_cache/disk_cache.h" |
+#include "net/disk_cache/v3/backend_impl_v3.h" |
+#include "net/disk_cache/v3/backend_work_item.h" |
+ |
+using base::Time; |
+using base::TimeDelta; |
+using disk_cache::CellId; |
+using disk_cache::CellList; |
+using disk_cache::IndexCell; |
+using disk_cache::IndexIterator; |
+ |
+namespace { |
+ |
+const uint32 kMaxAddress = 1 << 22; |
+const uint32 kBasicMask = 0xFFFF; |
+ |
+int GetSum(const IndexCell& cell) { |
+ return cell.timestamp_and_sum >> 6; |
+} |
+ |
+// This is a quite peculiar way to calculate the sum, so it will not match if |
+// compared a gainst a pure 2 bit, modulo 2 sum. |
+int CalculateSum(const IndexCell& cell) { |
+ uint32* word = bit_cast<uint32*>(&cell); |
+ uint32 result = word[0] + word[1]; |
+ result += result >> 16; |
+ result += (result >> 8) + (cell.timestamp_and_hash & 0x3f); |
+ result += result >> 4; |
+ result += result >> 2; |
+ return result & 3; |
+} |
+ |
+bool SanityCheck(const IndexCell& cell) { |
+ if (GetSum(cell) != CalculateSum(cell)) |
+ return false; |
+ |
+ if (cell.state > disk_cache::ENTRY_USED || |
+ cell.group == disk_cache::ENTRY_RESERVED || |
+ cell.group > disk_cache::ENTRY_EVICTED) { |
+ return false; |
+ } |
+ |
+ return true; |
+} |
+ |
+inline bool HashMatches(uint32 stored, uint32 value, int extra_bits) { |
+ return (stored >> extra_bits) == (value >> (14 + extra_bits)); |
+} |
+ |
+inline bool MisplacedHash(uint32 stored, uint32 value, int extra_bits) { |
+ if (!extra_bits) |
+ return false; |
+ uint32 mask = (1 << extra_bits) - 1; |
+ return (stored & mask) != ((value >> 14) & mask); |
+} |
+ |
+inline int GetNextBucket(int min_bucket_id, int max_bucket_id, |
+ disk_cache::IndexBucket* table, |
+ disk_cache::IndexBucket** bucket) { |
+ if (!(*bucket)->next) |
+ return 0; |
+ |
+ int bucket_id = (*bucket)->next / 4; |
+ if (bucket_id < min_bucket_id || bucket_id > max_bucket_id) { |
+ (*bucket)->next = 0; |
+ return 0; |
+ } |
+ *bucket = &table[bucket_id - min_bucket_id]; |
+ return bucket_id; |
+} |
+ |
+void UpdateListWithCell(int bucket_hash, const IndexCell& cell, CellList* list, |
+ int* list_time) { |
+ if (!list) |
+ return; |
+ |
+ int time = disk_cache::EntryCell::GetTimestamp(cell); |
+ if (time < *list_time) { |
+ *list_time = time; |
+ list->clear(); |
+ } |
+ if (time == *list_time) { |
+ CellId cell_id = { |
+ (disk_cache::EntryCell::GetHash(cell) << 14) + bucket_hash, |
+ disk_cache::Addr::FromEntryAddress(cell.address) |
+ }; |
+ list->push_back(cell_id); |
+ } |
+} |
+ |
+void GetNewestFromBucket(disk_cache::IndexBucket* bucket, int bucket_hash, |
+ int limit_time, IndexIterator* iterator) { |
+ for (int i = 0; i < 4; i++) { |
+ IndexCell& current_cell = bucket->cells[i]; |
+ if (!current_cell.address) |
+ continue; |
+ DCHECK(SanityCheck(current_cell)); |
+ if (!disk_cache::EntryCell::IsNormalState(current_cell)) |
+ continue; |
+ |
+ int time = disk_cache::EntryCell::GetTimestamp(current_cell); |
+ switch (current_cell.group) { |
+ case disk_cache::ENTRY_NO_USE: |
+ case disk_cache::ENTRY_LOW_USE: |
+ case disk_cache::ENTRY_HIGH_USE: |
+ if (iterator->forward && time >= limit_time) |
+ continue; |
+ if (!iterator->forward && time <= limit_time) |
+ continue; |
+ |
+ if ((iterator->forward && time > iterator->timestamp) || |
+ (!iterator->forward && time < iterator->timestamp)) { |
+ iterator->timestamp = time; |
+ iterator->cells.clear(); |
+ } |
+ if (time == iterator->timestamp) { |
+ CellId cell_id = { |
+ (disk_cache::EntryCell::GetHash(current_cell) << 14) + bucket_hash, |
+ disk_cache::Addr::FromEntryAddress(current_cell.address) |
+ }; |
+ iterator->cells.push_back(cell_id); |
+ } |
+ } |
+ } |
+} |
+ |
+} // namespace |
+ |
+namespace disk_cache { |
+ |
+EntryCell::EntryCell() : cell_id_(0), hash_(0) { |
+ cell_.Clear(); |
+} |
+ |
+EntryCell::EntryCell(int32 cell_id, uint32 hash, Addr address) |
+ : cell_id_(cell_id), |
+ hash_(hash) { |
+ DCHECK(ValidAddress(address) || !address.value()); |
+ |
+ cell_.Clear(); |
+ cell_.address = address.value() & 0xFFFFFF; |
+ cell_.state = ENTRY_NEW; |
+ cell_.group = ENTRY_NO_USE; |
+ cell_.hash = (hash >> 16) & kBasicMask; |
+ cell_.timestamp_and_hash = (hash >> 14) & 3; |
+} |
+ |
+EntryCell::EntryCell(int32 cell_id, uint32 hash, const IndexCell& cell) |
+ : cell_id_(cell_id), |
+ hash_(hash), |
+ cell_(cell) { |
+} |
+ |
+EntryCell::~EntryCell() { |
+} |
+ |
+Addr EntryCell::GetAddress() const { |
+ if (group() == ENTRY_EVICTED) |
+ return Addr::FromEvictedAddress(cell_.address); |
+ else |
+ return Addr::FromEntryAddress(cell_.address); |
+} |
+ |
+int EntryCell::GetTimestamp() const { |
+ return GetTimestamp(cell_); |
+} |
+ |
+void EntryCell::set_reuse(int count) { |
+ DCHECK_LT(count, 16); |
+ DCHECK_GE(count, 0); |
+ cell_.reuse = count; |
+} |
+ |
+// This operation destroys (ignores) the sum. |
+void EntryCell::set_timestamp(int timestamp) { |
+ DCHECK_LT(timestamp, 1 << 20); |
+ DCHECK_GE(timestamp, 0); |
+ cell_.timestamp_and_hash = ((timestamp & 0x3fff) << 2) + |
+ (cell_.timestamp_and_hash & 3); |
+ cell_.timestamp_and_sum = (timestamp >> 14) & 0x3f; |
+} |
+ |
+// Static. |
+bool EntryCell::ValidAddress(Addr address) { |
+ if (!address.is_initialized() || |
+ (address.file_type() != BLOCK_EVICTED && |
+ address.file_type() != BLOCK_ENTRIES)) { |
+ return false; |
+ } |
+ |
+ return (address.value() & 0xF00000) < kMaxAddress; |
+} |
+ |
+// Static. |
+uint32 EntryCell::GetHash(const IndexCell& cell) { |
+ return (cell.hash << 2) + (cell.timestamp_and_hash & 3); |
+} |
+ |
+// Static. |
+int EntryCell::GetTimestamp(const IndexCell& cell) { |
+ return (cell.timestamp_and_hash >> 2) + |
+ ((cell.timestamp_and_sum & 0x3f) << 14); |
+} |
+ |
+// Static. |
+bool EntryCell::IsNormalState(const IndexCell& cell) { |
+ EntryState state = static_cast<EntryState>(cell.state); |
+ DCHECK_NE(state, ENTRY_FREE); |
+ return state != ENTRY_DELETED && state != ENTRY_FIXING; |
+} |
+ |
+void EntryCell::FixSum() { |
+ cell_.timestamp_and_sum = (cell_.timestamp_and_sum & 0x3f) | |
+ (CalculateSum(cell_) << 6); |
+} |
+ |
+EntrySet::EntrySet() : evicted_count(0), current(0) { |
+} |
+ |
+// ----------------------------------------------------------------------- |
+ |
+IndexTable::IndexTable(BackendImplV3* backend) |
+ : backend_(backend), |
+ header_(NULL), |
+ main_table_(NULL), |
+ extra_table_(NULL) { |
+} |
+ |
+void IndexTable::Init(InitResult* params) { |
+ bool growing = header_ != NULL; |
+ IndexBucket* old_extra_table = NULL; |
+ header_ = ¶ms->index_bitmap->header; |
+ |
+ if (params->main_table) { |
+ if (main_table_) { |
+ DCHECK_EQ(header_->table_len / kIndexTablesize, |
+ backup_header_->table_len / kIndexTablesize + 1); |
+ old_extra_table = extra_table_; |
+ } |
+ main_table_ = params->main_table; |
+ } |
+ DCHECK(main_table_); |
+ extra_table_ = params->extra_table; |
+ |
+ extra_bits_ = header_->table_len / kIndexTablesize - 1; |
+ DCHECK_GE(extra_bits_, 0); |
+ DCHECK_LE(extra_bits_, 6); |
+ mask_ = ((kIndexTablesize / 4) << extra_bits_) - 1; |
+ |
+ int num_words = (header_->table_len + 31) / 32 ; |
+ bitmap_.reset(new Bitmap(params->index_bitmap->bitmap, header_->table_len, |
+ num_words)); |
+ |
+ if (growing) { |
+ int old_num_words = (backup_header_->table_len + 31) / 32; |
+ DCHECK_GE(num_words, old_num_words); |
+ scoped_ptr<uint32[]> storage(new uint32[num_words]); |
+ memcpy(storage.get(), backup_bitmap_storage_.get(), old_num_words * 4); |
+ memset(storage.get() + old_num_words, 0, (num_words - old_num_words) * 4); |
+ |
+ backup_bitmap_storage_.swap(storage); |
+ backup_header_->table_len = header_->table_len; |
+ } else { |
+ backup_bitmap_storage_.reset(params->backup_bitmap.release()); |
+ backup_header_.reset(params->backup_header.release()); |
+ } |
+ |
+ num_words = (backup_header_->table_len + 31) / 32; |
+ backup_bitmap_.reset(new Bitmap(backup_bitmap_storage_.get(), |
+ backup_header_->table_len, num_words)); |
+ if (old_extra_table) |
+ MoveCells(old_extra_table); |
+} |
+ |
+void IndexTable::Reset() { |
+ header_ = NULL; |
+ main_table_ = NULL; |
+ extra_table_ = NULL; |
+ bitmap_.reset(); |
+ backup_bitmap_.reset(); |
+ backup_header_.reset(); |
+ backup_bitmap_storage_.reset(); |
+} |
+ |
+EntrySet IndexTable::LookupEntry(uint32 hash) { |
+ EntrySet entries; |
+ int bucket_id = static_cast<int>(hash & mask_); |
+ IndexBucket* bucket = &main_table_[bucket_id]; |
+ for (;;) { |
+ for (int i = 0; i < 4; i++) { |
+ IndexCell* current_cell = &bucket->cells[i]; |
+ if (!current_cell->address) |
+ continue; |
+ if (!SanityCheck(*current_cell)) { |
+ NOTREACHED(); |
+ current_cell->Clear(); |
+ continue; |
+ } |
+ int cell_id = bucket_id * 4 + i; |
+ if (MisplacedHash(EntryCell::GetHash(*current_cell), hash, extra_bits_)) { |
+ HandleMisplacedCell(current_cell, cell_id, hash & mask_); |
+ } else if (HashMatches(EntryCell::GetHash(*current_cell), hash, |
+ extra_bits_)) { |
+ CheckState(current_cell, cell_id); |
+ if (current_cell->state != ENTRY_DELETED) { |
+ EntryCell entry_cell(cell_id, hash, *current_cell); |
+ entries.cells.push_back(entry_cell); |
+ if (current_cell->group == ENTRY_EVICTED) |
+ entries.evicted_count++; |
+ } |
+ } |
+ } |
+ bucket_id = GetNextBucket(mask_ + 1, header()->max_bucket, extra_table_, |
+ &bucket); |
+ if (!bucket_id) |
+ break; |
+ } |
+ return entries; |
+} |
+ |
+EntryCell IndexTable::CreateEntryCell(uint32 hash, Addr address) { |
+ DCHECK(EntryCell::ValidAddress(address)); |
+ |
+ int bucket_id = static_cast<int>(hash & mask_); |
+ int cell_id = 0; |
+ IndexBucket* bucket = &main_table_[bucket_id]; |
+ IndexCell* current_cell = NULL; |
+ bool found = false; |
+ for (; !found;) { |
+ for (int i = 0; i < 4 && !found; i++) { |
+ current_cell = &bucket->cells[i]; |
+ if (!current_cell->address) { |
+ cell_id = bucket_id * 4 + i; |
+ found = true; |
+ } |
+ } |
+ if (found) |
+ break; |
+ bucket_id = GetNextBucket(mask_ + 1, header()->max_bucket, extra_table_, |
+ &bucket); |
+ if (!bucket_id) |
+ break; |
+ } |
+ |
+ if (!found) { |
+ bucket_id = NewExtraBucket(); |
+ if (bucket_id) { |
+ cell_id = bucket_id * 4; |
+ bucket->next = cell_id; |
+ found = true; |
+ } else { |
+ // address 0 is a reserved value, and the caller interprets it as invalid. |
+ address.set_value(0); |
+ } |
+ } |
+ |
+ EntryCell entry_cell(cell_id, hash, address); |
+ if (address.file_type() == BLOCK_EVICTED) |
+ entry_cell.set_group(ENTRY_EVICTED); |
+ else |
+ entry_cell.set_group(ENTRY_NO_USE); |
+ Save(&entry_cell); |
+ |
+ if (found) { |
+ bitmap_->Set(cell_id, true); |
+ backup_bitmap_->Set(cell_id, true); |
+ header()->used_cells++; |
+ } |
+ |
+ return entry_cell; |
+} |
+ |
+bool IndexTable::SetSate(uint32 hash, Addr address, EntryState state) { |
+ EntryCell cell = FindEntryCellImpl(hash, address, state == ENTRY_FREE); |
+ if (!cell.IsValid()) |
+ return false; |
+ |
+ if (state == ENTRY_DELETED) { |
+ bitmap_->Set(cell.cell_id(), false); |
+ backup_bitmap_->Set(cell.cell_id(), false); |
+ } else if (state == ENTRY_FREE) { |
+ DCHECK_EQ(ENTRY_DELETED, cell.state()); |
+ cell.Clear(); |
+ Write(cell); |
+ header()->used_cells--; |
+ return true; |
+ } |
+ cell.set_state(state); |
+ |
+ Save(&cell); |
+ return true; |
+} |
+ |
+int IndexTable::GetTimestamp(Time time) { |
+ TimeDelta delta = time - Time::FromInternalValue(header_->base_time); |
+ return std::max(delta.InMinutes(), 0); |
+} |
+ |
+void IndexTable::UpdateTime(uint32 hash, Addr address) { |
+ EntryCell cell = FindEntryCell(hash, address); |
+ if (!cell.IsValid()) |
+ return; |
+ |
+ int minutes = GetTimestamp(backend_->GetCurrentTime()); |
+ |
+ // Keep about 3 months of headroom. |
+ const int kMaxTimestamp = (1 << 20) - 60 * 24 * 90; |
+ if (minutes > kMaxTimestamp) { |
+ // TODO(rvargas): |
+ // Update header->old_time and trigger a timer |
+ // Rebaseline timestamps and don't update sums |
+ // Start a timer (about 2 backups) |
+ // fix all ckecksums and trigger another timer |
+ // update header->old_time because rebaseline is done. |
+ minutes = std::min(minutes, (1 << 20) - 1); |
+ } |
+ |
+ cell.set_timestamp(minutes); |
+ Save(&cell); |
+} |
+ |
+EntryCell IndexTable::FindEntryCell(uint32 hash, Addr address) { |
+ return FindEntryCellImpl(hash, address, false); |
+} |
+ |
+void IndexTable::Save(EntryCell* cell) { |
+ cell->FixSum(); |
+ Write(*cell); |
+} |
+ |
+void IndexTable::GetOldest(CellList* no_use, CellList* low_use, |
+ CellList* high_use) { |
+ header_->num_no_use_entries = 0; |
+ header_->num_low_use_entries = 0; |
+ header_->num_high_use_entries = 0; |
+ header_->num_evicted_entries = 0; |
+ |
+ int no_use_time = kint32max; |
+ int low_use_time = kint32max; |
+ int high_use_time = kint32max; |
+ for (int i = 0; i < static_cast<int32>(mask_ + 1); i++) { |
+ int bucket_id = i; |
+ IndexBucket* bucket = &main_table_[i]; |
+ for (;;) { |
+ GetOldestFromBucket(bucket, i, no_use, &no_use_time, low_use, |
+ &low_use_time, high_use, &high_use_time); |
+ |
+ bucket_id = GetNextBucket(mask_ + 1, header()->max_bucket, extra_table_, |
+ &bucket); |
+ if (!bucket_id) |
+ break; |
+ } |
+ } |
+ header_->num_entries = header_->num_no_use_entries + |
+ header_->num_low_use_entries + |
+ header_->num_high_use_entries + |
+ header_->num_evicted_entries; |
+} |
+ |
+bool IndexTable::GetNextCells(IndexIterator* iterator) { |
+ int current_time = iterator->timestamp; |
+ size_t initial_size = iterator->cells.size(); |
+ iterator->timestamp = iterator->forward ? 0 : kint32max; |
+ |
+ for (int i = 0; i < static_cast<int32>(mask_ + 1); i++) { |
+ int bucket_id = i; |
+ IndexBucket* bucket = &main_table_[i]; |
+ for (;;) { |
+ GetNewestFromBucket(bucket, i, current_time, iterator); |
+ |
+ bucket_id = GetNextBucket(mask_ + 1, header()->max_bucket, extra_table_, |
+ &bucket); |
+ if (!bucket_id) |
+ break; |
+ } |
+ } |
+ return initial_size != iterator->cells.size(); |
+} |
+ |
+// ----------------------------------------------------------------------- |
+ |
+EntryCell IndexTable::FindEntryCellImpl(uint32 hash, Addr address, |
+ bool allow_deleted) { |
+ int bucket_id = static_cast<int>(hash & mask_); |
+ IndexBucket* bucket = &main_table_[bucket_id]; |
+ for (;;) { |
+ for (int i = 0; i < 4; i++) { |
+ IndexCell* current_cell = &bucket->cells[i]; |
+ if (!current_cell->address) |
+ continue; |
+ DCHECK(SanityCheck(*current_cell)); |
+ if (EntryCell::GetHash(*current_cell) == (hash >> 14)) { |
+ // We have a match. |
+ int cell_id = bucket_id * 4 + i; |
+ EntryCell entry_cell(cell_id, hash, *current_cell); |
+ if (entry_cell.GetAddress() != address) |
+ continue; |
+ |
+ if (!allow_deleted && entry_cell.state() == ENTRY_DELETED) |
+ continue; |
+ |
+ return entry_cell; |
+ } |
+ } |
+ bucket_id = GetNextBucket(mask_ + 1, header()->max_bucket, extra_table_, |
+ &bucket); |
+ if (!bucket_id) |
+ break; |
+ } |
+ return EntryCell(); |
+} |
+ |
+void IndexTable::CheckState(IndexCell* cell, int32 cell_id) { |
+ if (cell->state != ENTRY_FIXING) { |
+ bool present = ((cell->state & 3) != 0); // Look at the last two bits. |
+ if (present != bitmap_->Get(cell_id) || |
+ present != backup_bitmap_->Get(cell_id)) { |
+ // There's a mismatch. |
+ if (cell->state == ENTRY_DELETED) { |
+ // We were in the process of deleting this entry. Finish now. |
+ backend_->DeleteCell(cell, cell_id); |
+ } else { |
+ cell->state = ENTRY_FIXING; |
+ } |
+ } |
+ } |
+ |
+ if (cell->state == ENTRY_FIXING) |
+ backend_->FixCell(cell, cell_id); |
+} |
+ |
+void IndexTable::Write(const EntryCell& cell) { |
+ if (!cell.IsValid()) |
+ return; |
+ |
+ IndexBucket* bucket = NULL; |
+ int bucket_id = cell.cell_id() / 4; |
+ if (bucket_id < static_cast<int32>(mask_ + 1)) { |
+ bucket = &main_table_[bucket_id]; |
+ } else { |
+ DCHECK_LE(bucket_id, header()->max_bucket); |
+ bucket = &extra_table_[bucket_id - (mask_ + 1)]; |
+ } |
+ memcpy(&bucket->cells[cell.cell_id() % 4], &cell.cell(), sizeof(IndexCell)); |
+} |
+ |
+int IndexTable::NewExtraBucket() { |
+ if (header()->table_len - header()->max_bucket * 4 < kNumExtraBlocks) |
+ backend_->GrowIndex(); |
+ |
+ if (header()->max_bucket * 4 == header()->table_len - 4) |
+ return 0; |
+ |
+ header()->max_bucket++; |
+ return header()->max_bucket; |
+} |
+ |
+void IndexTable::GetOldestFromBucket(IndexBucket* bucket, int bucket_hash, |
+ CellList* no_use, int* no_use_time, |
+ CellList* low_use, int* low_use_time, |
+ CellList* high_use, int* high_use_time) { |
+ for (int i = 0; i < 4; i++) { |
+ IndexCell& current_cell = bucket->cells[i]; |
+ if (!current_cell.address) |
+ continue; |
+ DCHECK(SanityCheck(current_cell)); |
+ if (!EntryCell::IsNormalState(current_cell)) |
+ continue; |
+ |
+ int time = EntryCell::GetTimestamp(current_cell); |
+ switch (current_cell.group) { |
+ case ENTRY_NO_USE: |
+ UpdateListWithCell(bucket_hash, current_cell, no_use, no_use_time); |
+ header_->num_no_use_entries++; |
+ break; |
+ case ENTRY_LOW_USE: |
+ UpdateListWithCell(bucket_hash, current_cell, low_use, low_use_time); |
+ header_->num_low_use_entries++; |
+ break; |
+ case ENTRY_HIGH_USE: |
+ UpdateListWithCell(bucket_hash, current_cell, high_use, high_use_time); |
+ header_->num_high_use_entries++; |
+ break; |
+ case ENTRY_EVICTED: |
+ header_->num_evicted_entries++; |
+ break; |
+ default: |
+ NOTREACHED(); |
+ } |
+ } |
+} |
+ |
+void IndexTable::MoveCells(IndexBucket* old_extra_table) { |
+ int max_hash = (mask_ + 1) / 2; |
+ int max_bucket = header()->max_bucket; |
+ header()->max_bucket = mask_; |
+ |
+ // A cell stores the upper 18 bits of the hash (h >> 14). If the table is say |
+ // 8 times the original size (growing from 4x), the bit that we are interested |
+ // in would be the 3rd bit of the stored value, in other words multiplir >> 1. |
+ uint32 new_bit = ((mask_ + 1) * 4 / kIndexTablesize) >> 1; |
+ |
+ for (int i = 0; i < max_hash; i++) { |
+ int bucket_id = i; |
+ IndexBucket* bucket = &main_table_[i]; |
+ for (;;) { |
+ for (int j = 0; j < 4; j++) { |
+ IndexCell& current_cell = bucket->cells[j]; |
+ if (!current_cell.address) |
+ continue; |
+ DCHECK(SanityCheck(current_cell)); |
+ if (bucket_id == i) { |
+ if (EntryCell::GetHash(current_cell) & new_bit) { |
+ // Move this cell to the upper half of the table. |
+ MoveSingleCell(¤t_cell, bucket_id * 4 + j, i, true); |
+ } |
+ } else { |
+ // All cells on extra buckets have to move. |
+ MoveSingleCell(¤t_cell, bucket_id * 4 + j, i, true); |
+ } |
+ } |
+ |
+ bucket_id = GetNextBucket(max_hash, max_bucket, old_extra_table, &bucket); |
+ if (!bucket_id) |
+ break; |
+ } |
+ } |
+} |
+ |
+void IndexTable::MoveSingleCell(IndexCell* current_cell, int cell_id, |
+ int main_table_index, bool growing) { |
+ uint32 hash = (EntryCell::GetHash(*current_cell) << 14) | main_table_index; |
+ EntryCell old_cell(cell_id, hash, *current_cell); |
+ |
+ EntryCell new_cell = CreateEntryCell(hash, old_cell.GetAddress()); |
+ if (!new_cell.IsValid()) |
+ return; // We'll deal with this entry later. |
+ |
+ new_cell.set_state(old_cell.state()); |
+ new_cell.set_group(old_cell.group()); |
+ new_cell.set_reuse(old_cell.reuse()); |
+ new_cell.set_timestamp(old_cell.GetTimestamp()); |
+ Save(&new_cell); |
+ |
+ if (old_cell.state() == ENTRY_DELETED) { |
+ bitmap_->Set(new_cell.cell_id(), false); |
+ backup_bitmap_->Set(new_cell.cell_id(), false); |
+ } |
+ |
+ if (!growing || cell_id / 4 == main_table_index) { |
+ // Only delete entries that live on the main table. |
+ old_cell.Clear(); |
+ Write(old_cell); |
+ } |
+} |
+ |
+void IndexTable::HandleMisplacedCell(IndexCell* current_cell, int cell_id, |
+ int main_table_index) { |
+ // The cell may be misplaced, or a duplicate cell exists with this data. |
+ uint32 hash = (EntryCell::GetHash(*current_cell) << 14) | main_table_index; |
+ MoveSingleCell(current_cell, cell_id, main_table_index, false); |
+ |
+ // Now look for a duplicate cell. |
+ CheckBucketList(hash & mask_); |
+} |
+ |
+void IndexTable::CheckBucketList(int bucket_id) { |
+ typedef std::pair<int, EntryGroup> AddressAndGroup; |
+ std::set<AddressAndGroup> entries; |
+ IndexBucket* bucket = &main_table_[bucket_id]; |
+ for (;;) { |
+ for (int i = 0; i < 4; i++) { |
+ IndexCell* current_cell = &bucket->cells[i]; |
+ if (!current_cell->address) |
+ continue; |
+ if (!SanityCheck(*current_cell)) { |
+ NOTREACHED(); |
+ current_cell->Clear(); |
+ continue; |
+ } |
+ int cell_id = bucket_id * 4 + i; |
+ EntryCell cell(cell_id, 0, *current_cell); |
+ if (!entries.insert(std::make_pair(cell.GetAddress().value(), |
+ cell.group())).second) { |
+ current_cell->Clear(); |
+ continue; |
+ } |
+ CheckState(current_cell, cell_id); |
+ } |
+ |
+ bucket_id = GetNextBucket(mask_ + 1, header()->max_bucket, extra_table_, |
+ &bucket); |
+ if (!bucket_id) |
+ break; |
+ } |
+} |
+ |
+// Things we can be doing: |
+// |
+// - Updating timestamps |
+// Fast, but we go through a few backup cycles to make sure it sticks |
+// - Growing the extra table -> increase bitmap size, remap |
+// Just a matter of tripping to the cache thread. Everything keeps moving |
+// - Growing the whole table -> relocating all entries, may take a while |
+// - Evictions... only when we are NOT doing something else? just find the |
+// entries again so that there's no invalidation of lists |
+ |
+} // namespace disk_cache |
Property changes on: net\disk_cache\v3\index_table.cc |
___________________________________________________________________ |
Added: svn:eol-style |
+ LF |