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Unified Diff: net/disk_cache/blockfile/index_table_v3.cc

Issue 992733002: Remove //net (except for Android test stuff) and sdch (Closed) Base URL: git@github.com:domokit/mojo.git@master
Patch Set: Created 5 years, 9 months ago
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Index: net/disk_cache/blockfile/index_table_v3.cc
diff --git a/net/disk_cache/blockfile/index_table_v3.cc b/net/disk_cache/blockfile/index_table_v3.cc
deleted file mode 100644
index 039cba7f0529e3844944e6c78d0f44dca8c69460..0000000000000000000000000000000000000000
--- a/net/disk_cache/blockfile/index_table_v3.cc
+++ /dev/null
@@ -1,1149 +0,0 @@
-// Copyright 2014 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/blockfile/index_table_v3.h"
-
-#include <algorithm>
-#include <set>
-#include <utility>
-
-#include "base/bits.h"
-#include "net/base/io_buffer.h"
-#include "net/base/net_errors.h"
-#include "net/disk_cache/disk_cache.h"
-
-using base::Time;
-using base::TimeDelta;
-using disk_cache::CellInfo;
-using disk_cache::CellList;
-using disk_cache::IndexCell;
-using disk_cache::IndexIterator;
-
-namespace {
-
-// The following constants describe the bitfields of an IndexCell so they are
-// implicitly synchronized with the descrption of IndexCell on file_format_v3.h.
-const uint64 kCellLocationMask = (1 << 22) - 1;
-const uint64 kCellIdMask = (1 << 18) - 1;
-const uint64 kCellTimestampMask = (1 << 20) - 1;
-const uint64 kCellReuseMask = (1 << 4) - 1;
-const uint8 kCellStateMask = (1 << 3) - 1;
-const uint8 kCellGroupMask = (1 << 3) - 1;
-const uint8 kCellSumMask = (1 << 2) - 1;
-
-const uint64 kCellSmallTableLocationMask = (1 << 16) - 1;
-const uint64 kCellSmallTableIdMask = (1 << 24) - 1;
-
-const int kCellIdOffset = 22;
-const int kCellTimestampOffset = 40;
-const int kCellReuseOffset = 60;
-const int kCellGroupOffset = 3;
-const int kCellSumOffset = 6;
-
-const int kCellSmallTableIdOffset = 16;
-
-// The number of bits that a hash has to be shifted to grab the part that
-// defines the cell id.
-const int kHashShift = 14;
-const int kSmallTableHashShift = 8;
-
-// Unfortunately we have to break the abstaction a little here: the file number
-// where entries are stored is outside of the control of this code, and it is
-// usually part of the stored address. However, for small tables we only store
-// 16 bits of the address so the file number is never stored on a cell. We have
-// to infere the file number from the type of entry (normal vs evicted), and
-// the knowledge that given that the table will not keep more than 64k entries,
-// a single file of each type is enough.
-const int kEntriesFile = disk_cache::BLOCK_ENTRIES - 1;
-const int kEvictedEntriesFile = disk_cache::BLOCK_EVICTED - 1;
-const int kMaxLocation = 1 << 22;
-const int kMinFileNumber = 1 << 16;
-
-uint32 GetCellLocation(const IndexCell& cell) {
- return cell.first_part & kCellLocationMask;
-}
-
-uint32 GetCellSmallTableLocation(const IndexCell& cell) {
- return cell.first_part & kCellSmallTableLocationMask;
-}
-
-uint32 GetCellId(const IndexCell& cell) {
- return (cell.first_part >> kCellIdOffset) & kCellIdMask;
-}
-
-uint32 GetCellSmallTableId(const IndexCell& cell) {
- return (cell.first_part >> kCellSmallTableIdOffset) &
- kCellSmallTableIdMask;
-}
-
-int GetCellTimestamp(const IndexCell& cell) {
- return (cell.first_part >> kCellTimestampOffset) & kCellTimestampMask;
-}
-
-int GetCellReuse(const IndexCell& cell) {
- return (cell.first_part >> kCellReuseOffset) & kCellReuseMask;
-}
-
-int GetCellState(const IndexCell& cell) {
- return cell.last_part & kCellStateMask;
-}
-
-int GetCellGroup(const IndexCell& cell) {
- return (cell.last_part >> kCellGroupOffset) & kCellGroupMask;
-}
-
-int GetCellSum(const IndexCell& cell) {
- return (cell.last_part >> kCellSumOffset) & kCellSumMask;
-}
-
-void SetCellLocation(IndexCell* cell, uint32 address) {
- DCHECK_LE(address, static_cast<uint32>(kCellLocationMask));
- cell->first_part &= ~kCellLocationMask;
- cell->first_part |= address;
-}
-
-void SetCellSmallTableLocation(IndexCell* cell, uint32 address) {
- DCHECK_LE(address, static_cast<uint32>(kCellSmallTableLocationMask));
- cell->first_part &= ~kCellSmallTableLocationMask;
- cell->first_part |= address;
-}
-
-void SetCellId(IndexCell* cell, uint32 hash) {
- DCHECK_LE(hash, static_cast<uint32>(kCellIdMask));
- cell->first_part &= ~(kCellIdMask << kCellIdOffset);
- cell->first_part |= static_cast<int64>(hash) << kCellIdOffset;
-}
-
-void SetCellSmallTableId(IndexCell* cell, uint32 hash) {
- DCHECK_LE(hash, static_cast<uint32>(kCellSmallTableIdMask));
- cell->first_part &= ~(kCellSmallTableIdMask << kCellSmallTableIdOffset);
- cell->first_part |= static_cast<int64>(hash) << kCellSmallTableIdOffset;
-}
-
-void SetCellTimestamp(IndexCell* cell, int timestamp) {
- DCHECK_LT(timestamp, 1 << 20);
- DCHECK_GE(timestamp, 0);
- cell->first_part &= ~(kCellTimestampMask << kCellTimestampOffset);
- cell->first_part |= static_cast<int64>(timestamp) << kCellTimestampOffset;
-}
-
-void SetCellReuse(IndexCell* cell, int count) {
- DCHECK_LT(count, 16);
- DCHECK_GE(count, 0);
- cell->first_part &= ~(kCellReuseMask << kCellReuseOffset);
- cell->first_part |= static_cast<int64>(count) << kCellReuseOffset;
-}
-
-void SetCellState(IndexCell* cell, disk_cache::EntryState state) {
- cell->last_part &= ~kCellStateMask;
- cell->last_part |= state;
-}
-
-void SetCellGroup(IndexCell* cell, disk_cache::EntryGroup group) {
- cell->last_part &= ~(kCellGroupMask << kCellGroupOffset);
- cell->last_part |= group << kCellGroupOffset;
-}
-
-void SetCellSum(IndexCell* cell, int sum) {
- DCHECK_LT(sum, 4);
- DCHECK_GE(sum, 0);
- cell->last_part &= ~(kCellSumMask << kCellSumOffset);
- cell->last_part |= sum << kCellSumOffset;
-}
-
-// This is a very particular way to calculate the sum, so it will not match if
-// compared a gainst a pure 2 bit, modulo 2 sum.
-int CalculateCellSum(const IndexCell& cell) {
- uint32* words = bit_cast<uint32*>(&cell);
- uint8* bytes = bit_cast<uint8*>(&cell);
- uint32 result = words[0] + words[1];
- result += result >> 16;
- result += (result >> 8) + (bytes[8] & 0x3f);
- result += result >> 4;
- result += result >> 2;
- return result & 3;
-}
-
-bool SanityCheck(const IndexCell& cell) {
- if (GetCellSum(cell) != CalculateCellSum(cell))
- return false;
-
- if (GetCellState(cell) > disk_cache::ENTRY_USED ||
- GetCellGroup(cell) == disk_cache::ENTRY_RESERVED ||
- GetCellGroup(cell) > disk_cache::ENTRY_EVICTED) {
- return false;
- }
-
- return true;
-}
-
-int FileNumberFromLocation(int location) {
- return location / kMinFileNumber;
-}
-
-int StartBlockFromLocation(int location) {
- return location % kMinFileNumber;
-}
-
-bool IsValidAddress(disk_cache::Addr address) {
- if (!address.is_initialized() ||
- (address.file_type() != disk_cache::BLOCK_EVICTED &&
- address.file_type() != disk_cache::BLOCK_ENTRIES)) {
- return false;
- }
-
- return address.FileNumber() < FileNumberFromLocation(kMaxLocation);
-}
-
-bool IsNormalState(const IndexCell& cell) {
- disk_cache::EntryState state =
- static_cast<disk_cache::EntryState>(GetCellState(cell));
- DCHECK_NE(state, disk_cache::ENTRY_FREE);
- return state != disk_cache::ENTRY_DELETED &&
- state != disk_cache::ENTRY_FIXING;
-}
-
-inline int GetNextBucket(int min_bucket_num, int max_bucket_num,
- disk_cache::IndexBucket* table,
- disk_cache::IndexBucket** bucket) {
- if (!(*bucket)->next)
- return 0;
-
- int bucket_num = (*bucket)->next / disk_cache::kCellsPerBucket;
- if (bucket_num < min_bucket_num || bucket_num > max_bucket_num) {
- // The next bucket must fall within the extra table. Note that this is not
- // an uncommon path as growing the table may not cleanup the link from the
- // main table to the extra table, and that cleanup is performed here when
- // accessing that bucket for the first time. This behavior has to change if
- // the tables are ever shrinked.
- (*bucket)->next = 0;
- return 0;
- }
- *bucket = &table[bucket_num - min_bucket_num];
- return bucket_num;
-}
-
-// Updates the |iterator| with the current |cell|. This cell may cause all
-// previous cells to be deleted (when a new target timestamp is found), the cell
-// may be added to the list (if it matches the target timestamp), or may it be
-// ignored.
-void UpdateIterator(const disk_cache::EntryCell& cell,
- int limit_time,
- IndexIterator* iterator) {
- int time = cell.GetTimestamp();
- // Look for not interesting times.
- if (iterator->forward && time <= limit_time)
- return;
- if (!iterator->forward && time >= limit_time)
- return;
-
- if ((iterator->forward && time < iterator->timestamp) ||
- (!iterator->forward && time > iterator->timestamp)) {
- // This timestamp is better than the one we had.
- iterator->timestamp = time;
- iterator->cells.clear();
- }
- if (time == iterator->timestamp) {
- CellInfo cell_info = { cell.hash(), cell.GetAddress() };
- iterator->cells.push_back(cell_info);
- }
-}
-
-void InitIterator(IndexIterator* iterator) {
- iterator->cells.clear();
- iterator->timestamp = iterator->forward ? kint32max : 0;
-}
-
-} // namespace
-
-namespace disk_cache {
-
-EntryCell::~EntryCell() {
-}
-
-bool EntryCell::IsValid() const {
- return GetCellLocation(cell_) != 0;
-}
-
-// This code has to map the cell address (up to 22 bits) to a general cache Addr
-// (up to 24 bits of general addressing). It also set the implied file_number
-// in the case of small tables. See also the comment by the definition of
-// kEntriesFile.
-Addr EntryCell::GetAddress() const {
- uint32 location = GetLocation();
- int file_number = FileNumberFromLocation(location);
- if (small_table_) {
- DCHECK_EQ(0, file_number);
- file_number = (GetGroup() == ENTRY_EVICTED) ? kEvictedEntriesFile :
- kEntriesFile;
- }
- DCHECK_NE(0, file_number);
- FileType file_type = (GetGroup() == ENTRY_EVICTED) ? BLOCK_EVICTED :
- BLOCK_ENTRIES;
- return Addr(file_type, 1, file_number, StartBlockFromLocation(location));
-}
-
-EntryState EntryCell::GetState() const {
- return static_cast<EntryState>(GetCellState(cell_));
-}
-
-EntryGroup EntryCell::GetGroup() const {
- return static_cast<EntryGroup>(GetCellGroup(cell_));
-}
-
-int EntryCell::GetReuse() const {
- return GetCellReuse(cell_);
-}
-
-int EntryCell::GetTimestamp() const {
- return GetCellTimestamp(cell_);
-}
-
-void EntryCell::SetState(EntryState state) {
- SetCellState(&cell_, state);
-}
-
-void EntryCell::SetGroup(EntryGroup group) {
- SetCellGroup(&cell_, group);
-}
-
-void EntryCell::SetReuse(int count) {
- SetCellReuse(&cell_, count);
-}
-
-void EntryCell::SetTimestamp(int timestamp) {
- SetCellTimestamp(&cell_, timestamp);
-}
-
-// Static.
-EntryCell EntryCell::GetEntryCellForTest(int32 cell_num,
- uint32 hash,
- Addr address,
- IndexCell* cell,
- bool small_table) {
- if (cell) {
- EntryCell entry_cell(cell_num, hash, *cell, small_table);
- return entry_cell;
- }
-
- return EntryCell(cell_num, hash, address, small_table);
-}
-
-void EntryCell::SerializaForTest(IndexCell* destination) {
- FixSum();
- Serialize(destination);
-}
-
-EntryCell::EntryCell() : cell_num_(0), hash_(0), small_table_(false) {
- cell_.Clear();
-}
-
-EntryCell::EntryCell(int32 cell_num,
- uint32 hash,
- Addr address,
- bool small_table)
- : cell_num_(cell_num),
- hash_(hash),
- small_table_(small_table) {
- DCHECK(IsValidAddress(address) || !address.value());
-
- cell_.Clear();
- SetCellState(&cell_, ENTRY_NEW);
- SetCellGroup(&cell_, ENTRY_NO_USE);
- if (small_table) {
- DCHECK(address.FileNumber() == kEntriesFile ||
- address.FileNumber() == kEvictedEntriesFile);
- SetCellSmallTableLocation(&cell_, address.start_block());
- SetCellSmallTableId(&cell_, hash >> kSmallTableHashShift);
- } else {
- uint32 location = address.FileNumber() << 16 | address.start_block();
- SetCellLocation(&cell_, location);
- SetCellId(&cell_, hash >> kHashShift);
- }
-}
-
-EntryCell::EntryCell(int32 cell_num,
- uint32 hash,
- const IndexCell& cell,
- bool small_table)
- : cell_num_(cell_num),
- hash_(hash),
- cell_(cell),
- small_table_(small_table) {
-}
-
-void EntryCell::FixSum() {
- SetCellSum(&cell_, CalculateCellSum(cell_));
-}
-
-uint32 EntryCell::GetLocation() const {
- if (small_table_)
- return GetCellSmallTableLocation(cell_);
-
- return GetCellLocation(cell_);
-}
-
-uint32 EntryCell::RecomputeHash() {
- if (small_table_) {
- hash_ &= (1 << kSmallTableHashShift) - 1;
- hash_ |= GetCellSmallTableId(cell_) << kSmallTableHashShift;
- return hash_;
- }
-
- hash_ &= (1 << kHashShift) - 1;
- hash_ |= GetCellId(cell_) << kHashShift;
- return hash_;
-}
-
-void EntryCell::Serialize(IndexCell* destination) const {
- *destination = cell_;
-}
-
-EntrySet::EntrySet() : evicted_count(0), current(0) {
-}
-
-EntrySet::~EntrySet() {
-}
-
-IndexIterator::IndexIterator() {
-}
-
-IndexIterator::~IndexIterator() {
-}
-
-IndexTableInitData::IndexTableInitData() {
-}
-
-IndexTableInitData::~IndexTableInitData() {
-}
-
-// -----------------------------------------------------------------------
-
-IndexTable::IndexTable(IndexTableBackend* backend)
- : backend_(backend),
- header_(NULL),
- main_table_(NULL),
- extra_table_(NULL),
- modified_(false),
- small_table_(false) {
-}
-
-IndexTable::~IndexTable() {
-}
-
-// For a general description of the index tables see:
-// http://www.chromium.org/developers/design-documents/network-stack/disk-cache/disk-cache-v3#TOC-Index
-//
-// The index is split between two tables: the main_table_ and the extra_table_.
-// The main table can grow only by doubling its number of cells, while the
-// extra table can grow slowly, because it only contain cells that overflow
-// from the main table. In order to locate a given cell, part of the hash is
-// used directly as an index into the main table; once that bucket is located,
-// all cells with that partial hash (i.e., belonging to that bucket) are
-// inspected, and if present, the next bucket (located on the extra table) is
-// then located. For more information on bucket chaining see:
-// http://www.chromium.org/developers/design-documents/network-stack/disk-cache/disk-cache-v3#TOC-Buckets
-//
-// There are two cases when increasing the size:
-// - Doubling the size of the main table
-// - Adding more entries to the extra table
-//
-// For example, consider a 64k main table with 8k cells on the extra table (for
-// a total of 72k cells). Init can be called to add another 8k cells at the end
-// (grow to 80k cells). When the size of the extra table approaches 64k, Init
-// can be called to double the main table (to 128k) and go back to a small extra
-// table.
-void IndexTable::Init(IndexTableInitData* params) {
- bool growing = header_ != NULL;
- scoped_ptr<IndexBucket[]> old_extra_table;
- header_ = &params->index_bitmap->header;
-
- if (params->main_table) {
- if (main_table_) {
- // This is doubling the size of main table.
- DCHECK_EQ(base::bits::Log2Floor(header_->table_len),
- base::bits::Log2Floor(backup_header_->table_len) + 1);
- int extra_size = (header()->max_bucket - mask_) * kCellsPerBucket;
- DCHECK_GE(extra_size, 0);
-
- // Doubling the size implies deleting the extra table and moving as many
- // cells as we can to the main table, so we first copy the old one. This
- // is not required when just growing the extra table because we don't
- // move any cell in that case.
- old_extra_table.reset(new IndexBucket[extra_size]);
- memcpy(old_extra_table.get(), extra_table_,
- extra_size * sizeof(IndexBucket));
- memset(params->extra_table, 0, extra_size * sizeof(IndexBucket));
- }
- main_table_ = params->main_table;
- }
- DCHECK(main_table_);
- extra_table_ = params->extra_table;
-
- // extra_bits_ is really measured against table-size specific values.
- const int kMaxAbsoluteExtraBits = 12; // From smallest to largest table.
- const int kMaxExtraBitsSmallTable = 6; // From smallest to 64K table.
-
- extra_bits_ = base::bits::Log2Floor(header_->table_len) -
- base::bits::Log2Floor(kBaseTableLen);
- DCHECK_GE(extra_bits_, 0);
- DCHECK_LT(extra_bits_, kMaxAbsoluteExtraBits);
-
- // Note that following the previous code the constants could be derived as
- // kMaxAbsoluteExtraBits = base::bits::Log2Floor(max table len) -
- // base::bits::Log2Floor(kBaseTableLen);
- // = 22 - base::bits::Log2Floor(1024) = 22 - 10;
- // kMaxExtraBitsSmallTable = base::bits::Log2Floor(max 16 bit table) - 10.
-
- mask_ = ((kBaseTableLen / kCellsPerBucket) << extra_bits_) - 1;
- small_table_ = extra_bits_ < kMaxExtraBitsSmallTable;
- if (!small_table_)
- extra_bits_ -= kMaxExtraBitsSmallTable;
-
- // table_len keeps the max number of cells stored by the index. We need a
- // bitmap with 1 bit per cell, and that bitmap has num_words 32-bit words.
- int num_words = (header_->table_len + 31) / 32;
-
- if (old_extra_table) {
- // All the cells from the extra table are moving to the new tables so before
- // creating the bitmaps, clear the part of the bitmap referring to the extra
- // table.
- int old_main_table_bit_words = ((mask_ >> 1) + 1) * kCellsPerBucket / 32;
- DCHECK_GT(num_words, old_main_table_bit_words);
- memset(params->index_bitmap->bitmap + old_main_table_bit_words, 0,
- (num_words - old_main_table_bit_words) * sizeof(int32));
-
- DCHECK(growing);
- int old_num_words = (backup_header_.get()->table_len + 31) / 32;
- DCHECK_GT(old_num_words, old_main_table_bit_words);
- memset(backup_bitmap_storage_.get() + old_main_table_bit_words, 0,
- (old_num_words - old_main_table_bit_words) * sizeof(int32));
- }
- bitmap_.reset(new Bitmap(params->index_bitmap->bitmap, header_->table_len,
- num_words));
-
- if (growing) {
- int old_num_words = (backup_header_.get()->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 * sizeof(int32));
- memset(storage.get() + old_num_words, 0,
- (num_words - old_num_words) * sizeof(int32));
-
- 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.get());
-
- if (small_table_)
- DCHECK(header_->flags & SMALL_CACHE);
-
- // All tables and backups are needed for operation.
- DCHECK(main_table_);
- DCHECK(extra_table_);
- DCHECK(bitmap_.get());
-}
-
-void IndexTable::Shutdown() {
- header_ = NULL;
- main_table_ = NULL;
- extra_table_ = NULL;
- bitmap_.reset();
- backup_bitmap_.reset();
- backup_header_.reset();
- backup_bitmap_storage_.reset();
- modified_ = false;
-}
-
-// The general method for locating cells is to:
-// 1. Get the first bucket. This usually means directly indexing the table (as
-// this method does), or iterating through all possible buckets.
-// 2. Iterate through all the cells in that first bucket.
-// 3. If there is a linked bucket, locate it directly in the extra table.
-// 4. Go back to 2, as needed.
-//
-// One consequence of this pattern is that we never start looking at buckets in
-// the extra table, unless we are following a link from the main table.
-EntrySet IndexTable::LookupEntries(uint32 hash) {
- EntrySet entries;
- int bucket_num = static_cast<int>(hash & mask_);
- IndexBucket* bucket = &main_table_[bucket_num];
- do {
- for (int i = 0; i < kCellsPerBucket; i++) {
- IndexCell* current_cell = &bucket->cells[i];
- if (!GetLocation(*current_cell))
- continue;
- if (!SanityCheck(*current_cell)) {
- NOTREACHED();
- int cell_num = bucket_num * kCellsPerBucket + i;
- current_cell->Clear();
- bitmap_->Set(cell_num, false);
- backup_bitmap_->Set(cell_num, false);
- modified_ = true;
- continue;
- }
- int cell_num = bucket_num * kCellsPerBucket + i;
- if (MisplacedHash(*current_cell, hash)) {
- HandleMisplacedCell(current_cell, cell_num, hash & mask_);
- } else if (IsHashMatch(*current_cell, hash)) {
- EntryCell entry_cell(cell_num, hash, *current_cell, small_table_);
- CheckState(entry_cell);
- if (entry_cell.GetState() != ENTRY_DELETED) {
- entries.cells.push_back(entry_cell);
- if (entry_cell.GetGroup() == ENTRY_EVICTED)
- entries.evicted_count++;
- }
- }
- }
- bucket_num = GetNextBucket(mask_ + 1, header()->max_bucket, extra_table_,
- &bucket);
- } while (bucket_num);
- return entries;
-}
-
-EntryCell IndexTable::CreateEntryCell(uint32 hash, Addr address) {
- DCHECK(IsValidAddress(address));
- DCHECK(address.FileNumber() || address.start_block());
-
- int bucket_num = static_cast<int>(hash & mask_);
- int cell_num = 0;
- IndexBucket* bucket = &main_table_[bucket_num];
- IndexCell* current_cell = NULL;
- bool found = false;
- do {
- for (int i = 0; i < kCellsPerBucket && !found; i++) {
- current_cell = &bucket->cells[i];
- if (!GetLocation(*current_cell)) {
- cell_num = bucket_num * kCellsPerBucket + i;
- found = true;
- }
- }
- if (found)
- break;
- bucket_num = GetNextBucket(mask_ + 1, header()->max_bucket, extra_table_,
- &bucket);
- } while (bucket_num);
-
- if (!found) {
- bucket_num = NewExtraBucket();
- if (bucket_num) {
- cell_num = bucket_num * kCellsPerBucket;
- bucket->next = cell_num;
- bucket = &extra_table_[bucket_num - (mask_ + 1)];
- bucket->hash = hash & mask_;
- found = true;
- } else {
- // address 0 is a reserved value, and the caller interprets it as invalid.
- address.set_value(0);
- }
- }
-
- EntryCell entry_cell(cell_num, hash, address, small_table_);
- if (address.file_type() == BLOCK_EVICTED)
- entry_cell.SetGroup(ENTRY_EVICTED);
- else
- entry_cell.SetGroup(ENTRY_NO_USE);
- Save(&entry_cell);
-
- if (found) {
- bitmap_->Set(cell_num, true);
- backup_bitmap_->Set(cell_num, true);
- header()->used_cells++;
- modified_ = true;
- }
-
- return entry_cell;
-}
-
-EntryCell IndexTable::FindEntryCell(uint32 hash, Addr address) {
- return FindEntryCellImpl(hash, address, false);
-}
-
-int IndexTable::CalculateTimestamp(Time time) {
- TimeDelta delta = time - Time::FromInternalValue(header_->base_time);
- return std::max(delta.InMinutes(), 0);
-}
-
-base::Time IndexTable::TimeFromTimestamp(int timestamp) {
- return Time::FromInternalValue(header_->base_time) +
- TimeDelta::FromMinutes(timestamp);
-}
-
-void IndexTable::SetSate(uint32 hash, Addr address, EntryState state) {
- EntryCell cell = FindEntryCellImpl(hash, address, state == ENTRY_FREE);
- if (!cell.IsValid()) {
- NOTREACHED();
- return;
- }
-
- EntryState old_state = cell.GetState();
- switch (state) {
- case ENTRY_FREE:
- DCHECK_EQ(old_state, ENTRY_DELETED);
- break;
- case ENTRY_NEW:
- DCHECK_EQ(old_state, ENTRY_FREE);
- break;
- case ENTRY_OPEN:
- DCHECK_EQ(old_state, ENTRY_USED);
- break;
- case ENTRY_MODIFIED:
- DCHECK_EQ(old_state, ENTRY_OPEN);
- break;
- case ENTRY_DELETED:
- DCHECK(old_state == ENTRY_NEW || old_state == ENTRY_OPEN ||
- old_state == ENTRY_MODIFIED);
- break;
- case ENTRY_USED:
- DCHECK(old_state == ENTRY_NEW || old_state == ENTRY_OPEN ||
- old_state == ENTRY_MODIFIED);
- break;
- case ENTRY_FIXING:
- break;
- };
-
- modified_ = true;
- if (state == ENTRY_DELETED) {
- bitmap_->Set(cell.cell_num(), false);
- backup_bitmap_->Set(cell.cell_num(), false);
- } else if (state == ENTRY_FREE) {
- cell.Clear();
- Write(cell);
- header()->used_cells--;
- return;
- }
- cell.SetState(state);
-
- Save(&cell);
-}
-
-void IndexTable::UpdateTime(uint32 hash, Addr address, base::Time current) {
- EntryCell cell = FindEntryCell(hash, address);
- if (!cell.IsValid())
- return;
-
- int minutes = CalculateTimestamp(current);
-
- // 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.SetTimestamp(minutes);
- Save(&cell);
-}
-
-void IndexTable::Save(EntryCell* cell) {
- cell->FixSum();
- Write(*cell);
-}
-
-void IndexTable::GetOldest(IndexIterator* no_use,
- IndexIterator* low_use,
- IndexIterator* high_use) {
- no_use->forward = true;
- low_use->forward = true;
- high_use->forward = true;
- InitIterator(no_use);
- InitIterator(low_use);
- InitIterator(high_use);
-
- WalkTables(-1, no_use, low_use, high_use);
-}
-
-bool IndexTable::GetNextCells(IndexIterator* iterator) {
- int current_time = iterator->timestamp;
- InitIterator(iterator);
-
- WalkTables(current_time, iterator, iterator, iterator);
- return !iterator->cells.empty();
-}
-
-void IndexTable::OnBackupTimer() {
- if (!modified_)
- return;
-
- int num_words = (header_->table_len + 31) / 32;
- int num_bytes = num_words * 4 + static_cast<int>(sizeof(*header_));
- scoped_refptr<net::IOBuffer> buffer(new net::IOBuffer(num_bytes));
- memcpy(buffer->data(), header_, sizeof(*header_));
- memcpy(buffer->data() + sizeof(*header_), backup_bitmap_storage_.get(),
- num_words * 4);
- backend_->SaveIndex(buffer.get(), num_bytes);
- modified_ = false;
-}
-
-// -----------------------------------------------------------------------
-
-EntryCell IndexTable::FindEntryCellImpl(uint32 hash, Addr address,
- bool allow_deleted) {
- int bucket_num = static_cast<int>(hash & mask_);
- IndexBucket* bucket = &main_table_[bucket_num];
- do {
- for (int i = 0; i < kCellsPerBucket; i++) {
- IndexCell* current_cell = &bucket->cells[i];
- if (!GetLocation(*current_cell))
- continue;
- DCHECK(SanityCheck(*current_cell));
- if (IsHashMatch(*current_cell, hash)) {
- // We have a match.
- int cell_num = bucket_num * kCellsPerBucket + i;
- EntryCell entry_cell(cell_num, hash, *current_cell, small_table_);
- if (entry_cell.GetAddress() != address)
- continue;
-
- if (!allow_deleted && entry_cell.GetState() == ENTRY_DELETED)
- continue;
-
- return entry_cell;
- }
- }
- bucket_num = GetNextBucket(mask_ + 1, header()->max_bucket, extra_table_,
- &bucket);
- } while (bucket_num);
- return EntryCell();
-}
-
-void IndexTable::CheckState(const EntryCell& cell) {
- int current_state = cell.GetState();
- if (current_state != ENTRY_FIXING) {
- bool present = ((current_state & 3) != 0); // Look at the last two bits.
- if (present != bitmap_->Get(cell.cell_num()) ||
- present != backup_bitmap_->Get(cell.cell_num())) {
- // There's a mismatch.
- if (current_state == ENTRY_DELETED) {
- // We were in the process of deleting this entry. Finish now.
- backend_->DeleteCell(cell);
- } else {
- current_state = ENTRY_FIXING;
- EntryCell bad_cell(cell);
- bad_cell.SetState(ENTRY_FIXING);
- Save(&bad_cell);
- }
- }
- }
-
- if (current_state == ENTRY_FIXING)
- backend_->FixCell(cell);
-}
-
-void IndexTable::Write(const EntryCell& cell) {
- IndexBucket* bucket = NULL;
- int bucket_num = cell.cell_num() / kCellsPerBucket;
- if (bucket_num < static_cast<int32>(mask_ + 1)) {
- bucket = &main_table_[bucket_num];
- } else {
- DCHECK_LE(bucket_num, header()->max_bucket);
- bucket = &extra_table_[bucket_num - (mask_ + 1)];
- }
-
- int cell_number = cell.cell_num() % kCellsPerBucket;
- if (GetLocation(bucket->cells[cell_number]) && cell.GetLocation()) {
- DCHECK_EQ(cell.GetLocation(),
- GetLocation(bucket->cells[cell_number]));
- }
- cell.Serialize(&bucket->cells[cell_number]);
-}
-
-int IndexTable::NewExtraBucket() {
- int safe_window = (header()->table_len < kNumExtraBlocks * 2) ?
- kNumExtraBlocks / 4 : kNumExtraBlocks;
- if (header()->table_len - header()->max_bucket * kCellsPerBucket <
- safe_window) {
- backend_->GrowIndex();
- }
-
- if (header()->max_bucket * kCellsPerBucket ==
- header()->table_len - kCellsPerBucket) {
- return 0;
- }
-
- header()->max_bucket++;
- return header()->max_bucket;
-}
-
-void IndexTable::WalkTables(int limit_time,
- IndexIterator* no_use,
- IndexIterator* low_use,
- IndexIterator* 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;
-
- for (int i = 0; i < static_cast<int32>(mask_ + 1); i++) {
- int bucket_num = i;
- IndexBucket* bucket = &main_table_[i];
- do {
- UpdateFromBucket(bucket, i, limit_time, no_use, low_use, high_use);
-
- bucket_num = GetNextBucket(mask_ + 1, header()->max_bucket, extra_table_,
- &bucket);
- } while (bucket_num);
- }
- header_->num_entries = header_->num_no_use_entries +
- header_->num_low_use_entries +
- header_->num_high_use_entries +
- header_->num_evicted_entries;
- modified_ = true;
-}
-
-void IndexTable::UpdateFromBucket(IndexBucket* bucket, int bucket_hash,
- int limit_time,
- IndexIterator* no_use,
- IndexIterator* low_use,
- IndexIterator* high_use) {
- for (int i = 0; i < kCellsPerBucket; i++) {
- IndexCell& current_cell = bucket->cells[i];
- if (!GetLocation(current_cell))
- continue;
- DCHECK(SanityCheck(current_cell));
- if (!IsNormalState(current_cell))
- continue;
-
- EntryCell entry_cell(0, GetFullHash(current_cell, bucket_hash),
- current_cell, small_table_);
- switch (GetCellGroup(current_cell)) {
- case ENTRY_NO_USE:
- UpdateIterator(entry_cell, limit_time, no_use);
- header_->num_no_use_entries++;
- break;
- case ENTRY_LOW_USE:
- UpdateIterator(entry_cell, limit_time, low_use);
- header_->num_low_use_entries++;
- break;
- case ENTRY_HIGH_USE:
- UpdateIterator(entry_cell, limit_time, high_use);
- header_->num_high_use_entries++;
- break;
- case ENTRY_EVICTED:
- header_->num_evicted_entries++;
- break;
- default:
- NOTREACHED();
- }
- }
-}
-
-// This code is only called from Init() so the internal state of this object is
-// in flux (this method is performing the last steps of re-initialization). As
-// such, random methods are not supposed to work at this point, so whatever this
-// method calls should be relatively well controlled and it may require some
-// degree of "stable state faking".
-void IndexTable::MoveCells(IndexBucket* old_extra_table) {
- int max_hash = (mask_ + 1) / 2;
- int max_bucket = header()->max_bucket;
- header()->max_bucket = mask_;
- int used_cells = header()->used_cells;
-
- // Consider a large cache: 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 'multiplier' >> 1.
- uint32 new_bit = (1 << extra_bits_) >> 1;
-
- scoped_ptr<IndexBucket[]> old_main_table;
- IndexBucket* source_table = main_table_;
- bool upgrade_format = !extra_bits_;
- if (upgrade_format) {
- // This method should deal with migrating a small table to a big one. Given
- // that the first thing to do is read the old table, set small_table_ for
- // the size of the old table. Now, when moving a cell, the result cannot be
- // placed in the old table or we will end up reading it again and attempting
- // to move it, so we have to copy the whole table at once.
- DCHECK(!small_table_);
- small_table_ = true;
- old_main_table.reset(new IndexBucket[max_hash]);
- memcpy(old_main_table.get(), main_table_, max_hash * sizeof(IndexBucket));
- memset(main_table_, 0, max_hash * sizeof(IndexBucket));
- source_table = old_main_table.get();
- }
-
- for (int i = 0; i < max_hash; i++) {
- int bucket_num = i;
- IndexBucket* bucket = &source_table[i];
- do {
- for (int j = 0; j < kCellsPerBucket; j++) {
- IndexCell& current_cell = bucket->cells[j];
- if (!GetLocation(current_cell))
- continue;
- DCHECK(SanityCheck(current_cell));
- if (bucket_num == i) {
- if (upgrade_format || (GetHashValue(current_cell) & new_bit)) {
- // Move this cell to the upper half of the table.
- MoveSingleCell(&current_cell, bucket_num * kCellsPerBucket + j, i,
- true);
- }
- } else {
- // All cells on extra buckets have to move.
- MoveSingleCell(&current_cell, bucket_num * kCellsPerBucket + j, i,
- true);
- }
- }
-
- // There is no need to clear the old bucket->next value because if falls
- // within the main table so it will be fixed when attempting to follow
- // the link.
- bucket_num = GetNextBucket(max_hash, max_bucket, old_extra_table,
- &bucket);
- } while (bucket_num);
- }
-
- DCHECK_EQ(header()->used_cells, used_cells);
-
- if (upgrade_format) {
- small_table_ = false;
- header()->flags &= ~SMALL_CACHE;
- }
-}
-
-void IndexTable::MoveSingleCell(IndexCell* current_cell, int cell_num,
- int main_table_index, bool growing) {
- uint32 hash = GetFullHash(*current_cell, main_table_index);
- EntryCell old_cell(cell_num, hash, *current_cell, small_table_);
-
- // This method may be called when moving entries from a small table to a
- // normal table. In that case, the caller (MoveCells) has to read the old
- // table, so it needs small_table_ set to true, but this method needs to
- // write to the new table so small_table_ has to be set to false, and the
- // value restored to true before returning.
- bool upgrade_format = !extra_bits_ && growing;
- if (upgrade_format)
- small_table_ = false;
- EntryCell new_cell = CreateEntryCell(hash, old_cell.GetAddress());
-
- if (!new_cell.IsValid()) {
- // We'll deal with this entry later.
- if (upgrade_format)
- small_table_ = true;
- return;
- }
-
- new_cell.SetState(old_cell.GetState());
- new_cell.SetGroup(old_cell.GetGroup());
- new_cell.SetReuse(old_cell.GetReuse());
- new_cell.SetTimestamp(old_cell.GetTimestamp());
- Save(&new_cell);
- modified_ = true;
- if (upgrade_format)
- small_table_ = true;
-
- if (old_cell.GetState() == ENTRY_DELETED) {
- bitmap_->Set(new_cell.cell_num(), false);
- backup_bitmap_->Set(new_cell.cell_num(), false);
- }
-
- if (!growing || cell_num / kCellsPerBucket == main_table_index) {
- // Only delete entries that live on the main table.
- if (!upgrade_format) {
- old_cell.Clear();
- Write(old_cell);
- }
-
- if (cell_num != new_cell.cell_num()) {
- bitmap_->Set(old_cell.cell_num(), false);
- backup_bitmap_->Set(old_cell.cell_num(), false);
- }
- }
- header()->used_cells--;
-}
-
-void IndexTable::HandleMisplacedCell(IndexCell* current_cell, int cell_num,
- int main_table_index) {
- NOTREACHED(); // No unit tests yet.
-
- // The cell may be misplaced, or a duplicate cell exists with this data.
- uint32 hash = GetFullHash(*current_cell, main_table_index);
- MoveSingleCell(current_cell, cell_num, main_table_index, false);
-
- // Now look for a duplicate cell.
- CheckBucketList(hash & mask_);
-}
-
-void IndexTable::CheckBucketList(int bucket_num) {
- typedef std::pair<int, EntryGroup> AddressAndGroup;
- std::set<AddressAndGroup> entries;
- IndexBucket* bucket = &main_table_[bucket_num];
- int bucket_hash = bucket_num;
- do {
- for (int i = 0; i < kCellsPerBucket; i++) {
- IndexCell* current_cell = &bucket->cells[i];
- if (!GetLocation(*current_cell))
- continue;
- if (!SanityCheck(*current_cell)) {
- NOTREACHED();
- current_cell->Clear();
- continue;
- }
- int cell_num = bucket_num * kCellsPerBucket + i;
- EntryCell cell(cell_num, GetFullHash(*current_cell, bucket_hash),
- *current_cell, small_table_);
- if (!entries.insert(std::make_pair(cell.GetAddress().value(),
- cell.GetGroup())).second) {
- current_cell->Clear();
- continue;
- }
- CheckState(cell);
- }
-
- bucket_num = GetNextBucket(mask_ + 1, header()->max_bucket, extra_table_,
- &bucket);
- } while (bucket_num);
-}
-
-uint32 IndexTable::GetLocation(const IndexCell& cell) {
- if (small_table_)
- return GetCellSmallTableLocation(cell);
-
- return GetCellLocation(cell);
-}
-
-uint32 IndexTable::GetHashValue(const IndexCell& cell) {
- if (small_table_)
- return GetCellSmallTableId(cell);
-
- return GetCellId(cell);
-}
-
-uint32 IndexTable::GetFullHash(const IndexCell& cell, uint32 lower_part) {
- // It is OK for the high order bits of lower_part to overlap with the stored
- // part of the hash.
- if (small_table_)
- return (GetCellSmallTableId(cell) << kSmallTableHashShift) | lower_part;
-
- return (GetCellId(cell) << kHashShift) | lower_part;
-}
-
-// All the bits stored in the cell should match the provided hash.
-bool IndexTable::IsHashMatch(const IndexCell& cell, uint32 hash) {
- hash = small_table_ ? hash >> kSmallTableHashShift : hash >> kHashShift;
- return GetHashValue(cell) == hash;
-}
-
-bool IndexTable::MisplacedHash(const IndexCell& cell, uint32 hash) {
- if (!extra_bits_)
- return false;
-
- uint32 mask = (1 << extra_bits_) - 1;
- hash = small_table_ ? hash >> kSmallTableHashShift : hash >> kHashShift;
- return (GetHashValue(cell) & mask) != (hash & mask);
-}
-
-} // namespace disk_cache
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