Remove //net (except for Android test stuff) and sdch

net/disk_cache/blockfile/sparse_control_v3.cc

Index: net/disk_cache/blockfile/sparse_control_v3.cc
diff --git a/net/disk_cache/blockfile/sparse_control_v3.cc b/net/disk_cache/blockfile/sparse_control_v3.cc
deleted file mode 100644
index cba0ed5393f180e17dce388c900119f8df22ccb5..0000000000000000000000000000000000000000
--- a/net/disk_cache/blockfile/sparse_control_v3.cc
+++ /dev/null
@@ -1,868 +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.
-
-#include "net/disk_cache/blockfile/sparse_control.h"
-
-#include "base/bind.h"
-#include "base/format_macros.h"
-#include "base/logging.h"
-#include "base/message_loop/message_loop.h"
-#include "base/strings/string_util.h"
-#include "base/strings/stringprintf.h"
-#include "base/time/time.h"
-#include "net/base/io_buffer.h"
-#include "net/base/net_errors.h"
-#include "net/disk_cache/blockfile/backend_impl.h"
-#include "net/disk_cache/blockfile/entry_impl.h"
-#include "net/disk_cache/blockfile/file.h"
-#include "net/disk_cache/net_log_parameters.h"
-
-using base::Time;
-
-namespace {
-
-// Stream of the sparse data index.
-const int kSparseIndex = 2;
-
-// Stream of the sparse data.
-const int kSparseData = 1;
-
-// We can have up to 64k children.
-const int kMaxMapSize = 8 * 1024;
-
-// The maximum number of bytes that a child can store.
-const int kMaxEntrySize = 0x100000;
-
-// The size of each data block (tracked by the child allocation bitmap).
-const int kBlockSize = 1024;
-
-// Returns the name of a child entry given the base_name and signature of the
-// parent and the child_id.
-// If the entry is called entry_name, child entries will be named something
-// like Range_entry_name:XXX:YYY where XXX is the entry signature and YYY is the
-// number of the particular child.
-std::string GenerateChildName(const std::string& base_name, int64 signature,
-                              int64 child_id) {
-  return base::StringPrintf("Range_%s:%" PRIx64 ":%" PRIx64, base_name.c_str(),
-                            signature, child_id);
-}
-
-// This class deletes the children of a sparse entry.
-class ChildrenDeleter
-    : public base::RefCounted<ChildrenDeleter>,
-      public disk_cache::FileIOCallback {
- public:
-  ChildrenDeleter(disk_cache::BackendImpl* backend, const std::string& name)
-      : backend_(backend->GetWeakPtr()), name_(name), signature_(0) {}
-
-  virtual void OnFileIOComplete(int bytes_copied) override;
-
-  // Two ways of deleting the children: if we have the children map, use Start()
-  // directly, otherwise pass the data address to ReadData().
-  void Start(char* buffer, int len);
-  void ReadData(disk_cache::Addr address, int len);
-
- private:
-  friend class base::RefCounted<ChildrenDeleter>;
-  virtual ~ChildrenDeleter() {}
-
-  void DeleteChildren();
-
-  base::WeakPtr<disk_cache::BackendImpl> backend_;
-  std::string name_;
-  disk_cache::Bitmap children_map_;
-  int64 signature_;
-  scoped_ptr<char[]> buffer_;
-  DISALLOW_COPY_AND_ASSIGN(ChildrenDeleter);
-};
-
-// This is the callback of the file operation.
-void ChildrenDeleter::OnFileIOComplete(int bytes_copied) {
-  char* buffer = buffer_.release();
-  Start(buffer, bytes_copied);
-}
-
-void ChildrenDeleter::Start(char* buffer, int len) {
-  buffer_.reset(buffer);
-  if (len < static_cast<int>(sizeof(disk_cache::SparseData)))
-    return Release();
-
-  // Just copy the information from |buffer|, delete |buffer| and start deleting
-  // the child entries.
-  disk_cache::SparseData* data =
-      reinterpret_cast<disk_cache::SparseData*>(buffer);
-  signature_ = data->header.signature;
-
-  int num_bits = (len - sizeof(disk_cache::SparseHeader)) * 8;
-  children_map_.Resize(num_bits, false);
-  children_map_.SetMap(data->bitmap, num_bits / 32);
-  buffer_.reset();
-
-  DeleteChildren();
-}
-
-void ChildrenDeleter::ReadData(disk_cache::Addr address, int len) {
-  DCHECK(address.is_block_file());
-  if (!backend_)
-    return Release();
-
-  disk_cache::File* file(backend_->File(address));
-  if (!file)
-    return Release();
-
-  size_t file_offset = address.start_block() * address.BlockSize() +
-                       disk_cache::kBlockHeaderSize;
-
-  buffer_.reset(new char[len]);
-  bool completed;
-  if (!file->Read(buffer_.get(), len, file_offset, this, &completed))
-    return Release();
-
-  if (completed)
-    OnFileIOComplete(len);
-
-  // And wait until OnFileIOComplete gets called.
-}
-
-void ChildrenDeleter::DeleteChildren() {
-  int child_id = 0;
-  if (!children_map_.FindNextSetBit(&child_id) || !backend_) {
-    // We are done. Just delete this object.
-    return Release();
-  }
-  std::string child_name = GenerateChildName(name_, signature_, child_id);
-  backend_->SyncDoomEntry(child_name);
-  children_map_.Set(child_id, false);
-
-  // Post a task to delete the next child.
-  base::MessageLoop::current()->PostTask(
-      FROM_HERE, base::Bind(&ChildrenDeleter::DeleteChildren, this));
-}
-
-// -----------------------------------------------------------------------
-
-// Returns the NetLog event type corresponding to a SparseOperation.
-net::NetLog::EventType GetSparseEventType(
-    disk_cache::SparseControl::SparseOperation operation) {
-  switch (operation) {
-    case disk_cache::SparseControl::kReadOperation:
-      return net::NetLog::TYPE_SPARSE_READ;
-    case disk_cache::SparseControl::kWriteOperation:
-      return net::NetLog::TYPE_SPARSE_WRITE;
-    case disk_cache::SparseControl::kGetRangeOperation:
-      return net::NetLog::TYPE_SPARSE_GET_RANGE;
-    default:
-      NOTREACHED();
-      return net::NetLog::TYPE_CANCELLED;
-  }
-}
-
-// Logs the end event for |operation| on a child entry.  Range operations log
-// no events for each child they search through.
-void LogChildOperationEnd(const net::BoundNetLog& net_log,
-                          disk_cache::SparseControl::SparseOperation operation,
-                          int result) {
-  if (net_log.IsLogging()) {
-    net::NetLog::EventType event_type;
-    switch (operation) {
-      case disk_cache::SparseControl::kReadOperation:
-        event_type = net::NetLog::TYPE_SPARSE_READ_CHILD_DATA;
-        break;
-      case disk_cache::SparseControl::kWriteOperation:
-        event_type = net::NetLog::TYPE_SPARSE_WRITE_CHILD_DATA;
-        break;
-      case disk_cache::SparseControl::kGetRangeOperation:
-        return;
-      default:
-        NOTREACHED();
-        return;
-    }
-    net_log.EndEventWithNetErrorCode(event_type, result);
-  }
-}
-
-}  // namespace.
-
-namespace disk_cache {
-
-SparseControl::SparseControl(EntryImpl* entry)
-    : entry_(entry),
-      child_(NULL),
-      operation_(kNoOperation),
-      pending_(false),
-      finished_(false),
-      init_(false),
-      range_found_(false),
-      abort_(false),
-      child_map_(child_data_.bitmap, kNumSparseBits, kNumSparseBits / 32),
-      offset_(0),
-      buf_len_(0),
-      child_offset_(0),
-      child_len_(0),
-      result_(0) {
-  memset(&sparse_header_, 0, sizeof(sparse_header_));
-  memset(&child_data_, 0, sizeof(child_data_));
-}
-
-SparseControl::~SparseControl() {
-  if (child_)
-    CloseChild();
-  if (init_)
-    WriteSparseData();
-}
-
-bool SparseControl::CouldBeSparse() const {
-  DCHECK(!init_);
-
-  if (entry_->GetDataSize(kSparseData))
-    return false;
-
-  // We don't verify the data, just see if it could be there.
-  return (entry_->GetDataSize(kSparseIndex) != 0);
-}
-
-int SparseControl::StartIO(SparseOperation op, int64 offset, net::IOBuffer* buf,
-                           int buf_len, const CompletionCallback& callback) {
-  DCHECK(init_);
-  // We don't support simultaneous IO for sparse data.
-  if (operation_ != kNoOperation)
-    return net::ERR_CACHE_OPERATION_NOT_SUPPORTED;
-
-  if (offset < 0 || buf_len < 0)
-    return net::ERR_INVALID_ARGUMENT;
-
-  // We only support up to 64 GB.
-  if (offset + buf_len >= 0x1000000000LL || offset + buf_len < 0)
-    return net::ERR_CACHE_OPERATION_NOT_SUPPORTED;
-
-  DCHECK(!user_buf_);
-  DCHECK(user_callback_.is_null());
-
-  if (!buf && (op == kReadOperation || op == kWriteOperation))
-    return 0;
-
-  // Copy the operation parameters.
-  operation_ = op;
-  offset_ = offset;
-  user_buf_ = buf ? new net::DrainableIOBuffer(buf, buf_len) : NULL;
-  buf_len_ = buf_len;
-  user_callback_ = callback;
-
-  result_ = 0;
-  pending_ = false;
-  finished_ = false;
-  abort_ = false;
-
-  if (entry_->net_log().IsLogging()) {
-    entry_->net_log().BeginEvent(
-        GetSparseEventType(operation_),
-        CreateNetLogSparseOperationCallback(offset_, buf_len_));
-  }
-  DoChildrenIO();
-
-  if (!pending_) {
-    // Everything was done synchronously.
-    operation_ = kNoOperation;
-    user_buf_ = NULL;
-    user_callback_.Reset();
-    return result_;
-  }
-
-  return net::ERR_IO_PENDING;
-}
-
-int SparseControl::GetAvailableRange(int64 offset, int len, int64* start) {
-  DCHECK(init_);
-  // We don't support simultaneous IO for sparse data.
-  if (operation_ != kNoOperation)
-    return net::ERR_CACHE_OPERATION_NOT_SUPPORTED;
-
-  DCHECK(start);
-
-  range_found_ = false;
-  int result = StartIO(
-      kGetRangeOperation, offset, NULL, len, CompletionCallback());
-  if (range_found_) {
-    *start = offset_;
-    return result;
-  }
-
-  // This is a failure. We want to return a valid start value in any case.
-  *start = offset;
-  return result < 0 ? result : 0;  // Don't mask error codes to the caller.
-}
-
-void SparseControl::CancelIO() {
-  if (operation_ == kNoOperation)
-    return;
-  abort_ = true;
-}
-
-int SparseControl::ReadyToUse(const CompletionCallback& callback) {
-  if (!abort_)
-    return net::OK;
-
-  // We'll grab another reference to keep this object alive because we just have
-  // one extra reference due to the pending IO operation itself, but we'll
-  // release that one before invoking user_callback_.
-  entry_->AddRef();  // Balanced in DoAbortCallbacks.
-  abort_callbacks_.push_back(callback);
-  return net::ERR_IO_PENDING;
-}
-
-// Static
-void SparseControl::DeleteChildren(EntryImpl* entry) {
-  DCHECK(entry->GetEntryFlags() & PARENT_ENTRY);
-  int data_len = entry->GetDataSize(kSparseIndex);
-  if (data_len < static_cast<int>(sizeof(SparseData)) ||
-      entry->GetDataSize(kSparseData))
-    return;
-
-  int map_len = data_len - sizeof(SparseHeader);
-  if (map_len > kMaxMapSize || map_len % 4)
-    return;
-
-  char* buffer;
-  Addr address;
-  entry->GetData(kSparseIndex, &buffer, &address);
-  if (!buffer && !address.is_initialized())
-    return;
-
-  entry->net_log().AddEvent(net::NetLog::TYPE_SPARSE_DELETE_CHILDREN);
-
-  DCHECK(entry->backend_);
-  ChildrenDeleter* deleter = new ChildrenDeleter(entry->backend_.get(),
-                                                 entry->GetKey());
-  // The object will self destruct when finished.
-  deleter->AddRef();
-
-  if (buffer) {
-    base::MessageLoop::current()->PostTask(
-        FROM_HERE,
-        base::Bind(&ChildrenDeleter::Start, deleter, buffer, data_len));
-  } else {
-    base::MessageLoop::current()->PostTask(
-        FROM_HERE,
-        base::Bind(&ChildrenDeleter::ReadData, deleter, address, data_len));
-  }
-}
-
-// -----------------------------------------------------------------------
-
-int SparseControl::Init() {
-  DCHECK(!init_);
-
-  // We should not have sparse data for the exposed entry.
-  if (entry_->GetDataSize(kSparseData))
-    return net::ERR_CACHE_OPERATION_NOT_SUPPORTED;
-
-  // Now see if there is something where we store our data.
-  int rv = net::OK;
-  int data_len = entry_->GetDataSize(kSparseIndex);
-  if (!data_len) {
-    rv = CreateSparseEntry();
-  } else {
-    rv = OpenSparseEntry(data_len);
-  }
-
-  if (rv == net::OK)
-    init_ = true;
-  return rv;
-}
-
-// We are going to start using this entry to store sparse data, so we have to
-// initialize our control info.
-int SparseControl::CreateSparseEntry() {
-  if (CHILD_ENTRY & entry_->GetEntryFlags())
-    return net::ERR_CACHE_OPERATION_NOT_SUPPORTED;
-
-  memset(&sparse_header_, 0, sizeof(sparse_header_));
-  sparse_header_.signature = Time::Now().ToInternalValue();
-  sparse_header_.magic = kIndexMagic;
-  sparse_header_.parent_key_len = entry_->GetKey().size();
-  children_map_.Resize(kNumSparseBits, true);
-
-  // Save the header. The bitmap is saved in the destructor.
-  scoped_refptr<net::IOBuffer> buf(
-      new net::WrappedIOBuffer(reinterpret_cast<char*>(&sparse_header_)));
-
-  int rv = entry_->WriteData(kSparseIndex, 0, buf.get(), sizeof(sparse_header_),
-                             CompletionCallback(), false);
-  if (rv != sizeof(sparse_header_)) {
-    DLOG(ERROR) << "Unable to save sparse_header_";
-    return net::ERR_CACHE_OPERATION_NOT_SUPPORTED;
-  }
-
-  entry_->SetEntryFlags(PARENT_ENTRY);
-  return net::OK;
-}
-
-// We are opening an entry from disk. Make sure that our control data is there.
-int SparseControl::OpenSparseEntry(int data_len) {
-  if (data_len < static_cast<int>(sizeof(SparseData)))
-    return net::ERR_CACHE_OPERATION_NOT_SUPPORTED;
-
-  if (entry_->GetDataSize(kSparseData))
-    return net::ERR_CACHE_OPERATION_NOT_SUPPORTED;
-
-  if (!(PARENT_ENTRY & entry_->GetEntryFlags()))
-    return net::ERR_CACHE_OPERATION_NOT_SUPPORTED;
-
-  // Dont't go over board with the bitmap. 8 KB gives us offsets up to 64 GB.
-  int map_len = data_len - sizeof(sparse_header_);
-  if (map_len > kMaxMapSize || map_len % 4)
-    return net::ERR_CACHE_OPERATION_NOT_SUPPORTED;
-
-  scoped_refptr<net::IOBuffer> buf(
-      new net::WrappedIOBuffer(reinterpret_cast<char*>(&sparse_header_)));
-
-  // Read header.
-  int rv = entry_->ReadData(kSparseIndex, 0, buf.get(), sizeof(sparse_header_),
-                            CompletionCallback());
-  if (rv != static_cast<int>(sizeof(sparse_header_)))
-    return net::ERR_CACHE_READ_FAILURE;
-
-  // The real validation should be performed by the caller. This is just to
-  // double check.
-  if (sparse_header_.magic != kIndexMagic ||
-      sparse_header_.parent_key_len !=
-          static_cast<int>(entry_->GetKey().size()))
-    return net::ERR_CACHE_OPERATION_NOT_SUPPORTED;
-
-  // Read the actual bitmap.
-  buf = new net::IOBuffer(map_len);
-  rv = entry_->ReadData(kSparseIndex, sizeof(sparse_header_), buf.get(),
-                        map_len, CompletionCallback());
-  if (rv != map_len)
-    return net::ERR_CACHE_READ_FAILURE;
-
-  // Grow the bitmap to the current size and copy the bits.
-  children_map_.Resize(map_len * 8, false);
-  children_map_.SetMap(reinterpret_cast<uint32*>(buf->data()), map_len);
-  return net::OK;
-}
-
-bool SparseControl::OpenChild() {
-  DCHECK_GE(result_, 0);
-
-  std::string key = GenerateChildKey();
-  if (child_) {
-    // Keep using the same child or open another one?.
-    if (key == child_->GetKey())
-      return true;
-    CloseChild();
-  }
-
-  // See if we are tracking this child.
-  if (!ChildPresent())
-    return ContinueWithoutChild(key);
-
-  if (!entry_->backend_)
-    return false;
-
-  child_ = entry_->backend_->OpenEntryImpl(key);
-  if (!child_)
-    return ContinueWithoutChild(key);
-
-  EntryImpl* child = static_cast<EntryImpl*>(child_);
-  if (!(CHILD_ENTRY & child->GetEntryFlags()) ||
-      child->GetDataSize(kSparseIndex) <
-          static_cast<int>(sizeof(child_data_)))
-    return KillChildAndContinue(key, false);
-
-  scoped_refptr<net::WrappedIOBuffer> buf(
-      new net::WrappedIOBuffer(reinterpret_cast<char*>(&child_data_)));
-
-  // Read signature.
-  int rv = child_->ReadData(kSparseIndex, 0, buf.get(), sizeof(child_data_),
-                            CompletionCallback());
-  if (rv != sizeof(child_data_))
-    return KillChildAndContinue(key, true);  // This is a fatal failure.
-
-  if (child_data_.header.signature != sparse_header_.signature ||
-      child_data_.header.magic != kIndexMagic)
-    return KillChildAndContinue(key, false);
-
-  if (child_data_.header.last_block_len < 0 ||
-      child_data_.header.last_block_len > kBlockSize) {
-    // Make sure these values are always within range.
-    child_data_.header.last_block_len = 0;
-    child_data_.header.last_block = -1;
-  }
-
-  return true;
-}
-
-void SparseControl::CloseChild() {
-  scoped_refptr<net::WrappedIOBuffer> buf(
-      new net::WrappedIOBuffer(reinterpret_cast<char*>(&child_data_)));
-
-  // Save the allocation bitmap before closing the child entry.
-  int rv = child_->WriteData(kSparseIndex, 0, buf.get(), sizeof(child_data_),
-                             CompletionCallback(),
-      false);
-  if (rv != sizeof(child_data_))
-    DLOG(ERROR) << "Failed to save child data";
-  child_->Release();
-  child_ = NULL;
-}
-
-// We were not able to open this child; see what we can do.
-bool SparseControl::ContinueWithoutChild(const std::string& key) {
-  if (kReadOperation == operation_)
-    return false;
-  if (kGetRangeOperation == operation_)
-    return true;
-
-  if (!entry_->backend_)
-    return false;
-
-  child_ = entry_->backend_->CreateEntryImpl(key);
-  if (!child_) {
-    child_ = NULL;
-    result_ = net::ERR_CACHE_READ_FAILURE;
-    return false;
-  }
-  // Write signature.
-  InitChildData();
-  return true;
-}
-
-void SparseControl::WriteSparseData() {
-  scoped_refptr<net::IOBuffer> buf(new net::WrappedIOBuffer(
-      reinterpret_cast<const char*>(children_map_.GetMap())));
-
-  int len = children_map_.ArraySize() * 4;
-  int rv = entry_->WriteData(kSparseIndex, sizeof(sparse_header_), buf.get(),
-                             len, CompletionCallback(), false);
-  if (rv != len) {
-    DLOG(ERROR) << "Unable to save sparse map";
-  }
-}
-
-bool SparseControl::DoChildIO() {
-  finished_ = true;
-  if (!buf_len_ || result_ < 0)
-    return false;
-
-  if (!OpenChild())
-    return false;
-
-  if (!VerifyRange())
-    return false;
-
-  // We have more work to do. Let's not trigger a callback to the caller.
-  finished_ = false;
-  CompletionCallback callback;
-  if (!user_callback_.is_null()) {
-    callback =
-        base::Bind(&SparseControl::OnChildIOCompleted, base::Unretained(this));
-  }
-
-  int rv = 0;
-  switch (operation_) {
-    case kReadOperation:
-      if (entry_->net_log().IsLogging()) {
-        entry_->net_log().BeginEvent(
-            net::NetLog::TYPE_SPARSE_READ_CHILD_DATA,
-            CreateNetLogSparseReadWriteCallback(child_->net_log().source(),
-                                                child_len_));
-      }
-      rv = child_->ReadDataImpl(kSparseData, child_offset_, user_buf_.get(),
-                                child_len_, callback);
-      break;
-    case kWriteOperation:
-      if (entry_->net_log().IsLogging()) {
-        entry_->net_log().BeginEvent(
-            net::NetLog::TYPE_SPARSE_WRITE_CHILD_DATA,
-            CreateNetLogSparseReadWriteCallback(child_->net_log().source(),
-                                                child_len_));
-      }
-      rv = child_->WriteDataImpl(kSparseData, child_offset_, user_buf_.get(),
-                                 child_len_, callback, false);
-      break;
-    case kGetRangeOperation:
-      rv = DoGetAvailableRange();
-      break;
-    default:
-      NOTREACHED();
-  }
-
-  if (rv == net::ERR_IO_PENDING) {
-    if (!pending_) {
-      pending_ = true;
-      // The child will protect himself against closing the entry while IO is in
-      // progress. However, this entry can still be closed, and that would not
-      // be a good thing for us, so we increase the refcount until we're
-      // finished doing sparse stuff.
-      entry_->AddRef();  // Balanced in DoUserCallback.
-    }
-    return false;
-  }
-  if (!rv)
-    return false;
-
-  DoChildIOCompleted(rv);
-  return true;
-}
-
-void SparseControl::DoChildIOCompleted(int result) {
-  LogChildOperationEnd(entry_->net_log(), operation_, result);
-  if (result < 0) {
-    // We fail the whole operation if we encounter an error.
-    result_ = result;
-    return;
-  }
-
-  UpdateRange(result);
-
-  result_ += result;
-  offset_ += result;
-  buf_len_ -= result;
-
-  // We'll be reusing the user provided buffer for the next chunk.
-  if (buf_len_ && user_buf_)
-    user_buf_->DidConsume(result);
-}
-
-std::string SparseControl::GenerateChildKey() {
-  return GenerateChildName(entry_->GetKey(), sparse_header_.signature,
-                           offset_ >> 20);
-}
-
-// We are deleting the child because something went wrong.
-bool SparseControl::KillChildAndContinue(const std::string& key, bool fatal) {
-  SetChildBit(false);
-  child_->DoomImpl();
-  child_->Release();
-  child_ = NULL;
-  if (fatal) {
-    result_ = net::ERR_CACHE_READ_FAILURE;
-    return false;
-  }
-  return ContinueWithoutChild(key);
-}
-
-bool SparseControl::ChildPresent() {
-  int child_bit = static_cast<int>(offset_ >> 20);
-  if (children_map_.Size() <= child_bit)
-    return false;
-
-  return children_map_.Get(child_bit);
-}
-
-void SparseControl::SetChildBit(bool value) {
-  int child_bit = static_cast<int>(offset_ >> 20);
-
-  // We may have to increase the bitmap of child entries.
-  if (children_map_.Size() <= child_bit)
-    children_map_.Resize(Bitmap::RequiredArraySize(child_bit + 1) * 32, true);
-
-  children_map_.Set(child_bit, value);
-}
-
-bool SparseControl::VerifyRange() {
-  DCHECK_GE(result_, 0);
-
-  child_offset_ = static_cast<int>(offset_) & (kMaxEntrySize - 1);
-  child_len_ = std::min(buf_len_, kMaxEntrySize - child_offset_);
-
-  // We can write to (or get info from) anywhere in this child.
-  if (operation_ != kReadOperation)
-    return true;
-
-  // Check that there are no holes in this range.
-  int last_bit = (child_offset_ + child_len_ + 1023) >> 10;
-  int start = child_offset_ >> 10;
-  if (child_map_.FindNextBit(&start, last_bit, false)) {
-    // Something is not here.
-    DCHECK_GE(child_data_.header.last_block_len, 0);
-    DCHECK_LT(child_data_.header.last_block_len, kMaxEntrySize);
-    int partial_block_len = PartialBlockLength(start);
-    if (start == child_offset_ >> 10) {
-      // It looks like we don't have anything.
-      if (partial_block_len <= (child_offset_ & (kBlockSize - 1)))
-        return false;
-    }
-
-    // We have the first part.
-    child_len_ = (start << 10) - child_offset_;
-    if (partial_block_len) {
-      // We may have a few extra bytes.
-      child_len_ = std::min(child_len_ + partial_block_len, buf_len_);
-    }
-    // There is no need to read more after this one.
-    buf_len_ = child_len_;
-  }
-  return true;
-}
-
-void SparseControl::UpdateRange(int result) {
-  if (result <= 0 || operation_ != kWriteOperation)
-    return;
-
-  DCHECK_GE(child_data_.header.last_block_len, 0);
-  DCHECK_LT(child_data_.header.last_block_len, kMaxEntrySize);
-
-  // Write the bitmap.
-  int first_bit = child_offset_ >> 10;
-  int block_offset = child_offset_ & (kBlockSize - 1);
-  if (block_offset && (child_data_.header.last_block != first_bit ||
-                       child_data_.header.last_block_len < block_offset)) {
-    // The first block is not completely filled; ignore it.
-    first_bit++;
-  }
-
-  int last_bit = (child_offset_ + result) >> 10;
-  block_offset = (child_offset_ + result) & (kBlockSize - 1);
-
-  // This condition will hit with the following criteria:
-  // 1. The first byte doesn't follow the last write.
-  // 2. The first byte is in the middle of a block.
-  // 3. The first byte and the last byte are in the same block.
-  if (first_bit > last_bit)
-    return;
-
-  if (block_offset && !child_map_.Get(last_bit)) {
-    // The last block is not completely filled; save it for later.
-    child_data_.header.last_block = last_bit;
-    child_data_.header.last_block_len = block_offset;
-  } else {
-    child_data_.header.last_block = -1;
-  }
-
-  child_map_.SetRange(first_bit, last_bit, true);
-}
-
-int SparseControl::PartialBlockLength(int block_index) const {
-  if (block_index == child_data_.header.last_block)
-    return child_data_.header.last_block_len;
-
-  // This may be the last stored index.
-  int entry_len = child_->GetDataSize(kSparseData);
-  if (block_index == entry_len >> 10)
-    return entry_len & (kBlockSize - 1);
-
-  // This is really empty.
-  return 0;
-}
-
-void SparseControl::InitChildData() {
-  // We know the real type of child_.
-  EntryImpl* child = static_cast<EntryImpl*>(child_);
-  child->SetEntryFlags(CHILD_ENTRY);
-
-  memset(&child_data_, 0, sizeof(child_data_));
-  child_data_.header = sparse_header_;
-
-  scoped_refptr<net::WrappedIOBuffer> buf(
-      new net::WrappedIOBuffer(reinterpret_cast<char*>(&child_data_)));
-
-  int rv = child_->WriteData(kSparseIndex, 0, buf.get(), sizeof(child_data_),
-                             CompletionCallback(), false);
-  if (rv != sizeof(child_data_))
-    DLOG(ERROR) << "Failed to save child data";
-  SetChildBit(true);
-}
-
-int SparseControl::DoGetAvailableRange() {
-  if (!child_)
-    return child_len_;  // Move on to the next child.
-
-  // Check that there are no holes in this range.
-  int last_bit = (child_offset_ + child_len_ + 1023) >> 10;
-  int start = child_offset_ >> 10;
-  int partial_start_bytes = PartialBlockLength(start);
-  int found = start;
-  int bits_found = child_map_.FindBits(&found, last_bit, true);
-
-  // We don't care if there is a partial block in the middle of the range.
-  int block_offset = child_offset_ & (kBlockSize - 1);
-  if (!bits_found && partial_start_bytes <= block_offset)
-    return child_len_;
-
-  // We are done. Just break the loop and reset result_ to our real result.
-  range_found_ = true;
-
-  // found now points to the first 1. Lets see if we have zeros before it.
-  int empty_start = std::max((found << 10) - child_offset_, 0);
-
-  int bytes_found = bits_found << 10;
-  bytes_found += PartialBlockLength(found + bits_found);
-
-  if (start == found)
-    bytes_found -= block_offset;
-
-  // If the user is searching past the end of this child, bits_found is the
-  // right result; otherwise, we have some empty space at the start of this
-  // query that we have to subtract from the range that we searched.
-  result_ = std::min(bytes_found, child_len_ - empty_start);
-
-  if (!bits_found) {
-    result_ = std::min(partial_start_bytes - block_offset, child_len_);
-    empty_start = 0;
-  }
-
-  // Only update offset_ when this query found zeros at the start.
-  if (empty_start)
-    offset_ += empty_start;
-
-  // This will actually break the loop.
-  buf_len_ = 0;
-  return 0;
-}
-
-void SparseControl::DoUserCallback() {
-  DCHECK(!user_callback_.is_null());
-  CompletionCallback cb = user_callback_;
-  user_callback_.Reset();
-  user_buf_ = NULL;
-  pending_ = false;
-  operation_ = kNoOperation;
-  int rv = result_;
-  entry_->Release();  // Don't touch object after this line.
-  cb.Run(rv);
-}
-
-void SparseControl::DoAbortCallbacks() {
-  for (size_t i = 0; i < abort_callbacks_.size(); i++) {
-    // Releasing all references to entry_ may result in the destruction of this
-    // object so we should not be touching it after the last Release().
-    CompletionCallback cb = abort_callbacks_[i];
-    if (i == abort_callbacks_.size() - 1)
-      abort_callbacks_.clear();
-
-    entry_->Release();  // Don't touch object after this line.
-    cb.Run(net::OK);
-  }
-}
-
-void SparseControl::OnChildIOCompleted(int result) {
-  DCHECK_NE(net::ERR_IO_PENDING, result);
-  DoChildIOCompleted(result);
-
-  if (abort_) {
-    // We'll return the current result of the operation, which may be less than
-    // the bytes to read or write, but the user cancelled the operation.
-    abort_ = false;
-    if (entry_->net_log().IsLogging()) {
-      entry_->net_log().AddEvent(net::NetLog::TYPE_CANCELLED);
-      entry_->net_log().EndEvent(GetSparseEventType(operation_));
-    }
-    // We have an indirect reference to this object for every callback so if
-    // there is only one callback, we may delete this object before reaching
-    // DoAbortCallbacks.
-    bool has_abort_callbacks = !abort_callbacks_.empty();
-    DoUserCallback();
-    if (has_abort_callbacks)
-      DoAbortCallbacks();
-    return;
-  }
-
-  // We are running a callback from the message loop. It's time to restart what
-  // we were doing before.
-  DoChildrenIO();
-}
-
-}  // namespace disk_cache