blob: b165839365892a174ad9cd3aaf61a5ae5ad49028 [file] [log] [blame]
// 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/http/mock_http_cache.h"
#include <algorithm>
#include <limits>
#include <memory>
#include <utility>
#include "base/bind.h"
#include "base/callback_helpers.h"
#include "base/location.h"
#include "base/single_thread_task_runner.h"
#include "base/threading/thread_task_runner_handle.h"
#include "net/base/net_errors.h"
#include "net/http/http_cache_writers.h"
#include "starboard/memory.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace net {
namespace {
// During testing, we are going to limit the size of a cache entry to this many
// bytes using DCHECKs in order to prevent a test from causing unbounded memory
// growth. In practice cache entry shouldn't come anywhere near this limit for
// tests that use the mock cache. If they do, that's likely a problem with the
// test. If a test requires using massive cache entries, they should use a real
// cache backend instead.
const int kMaxMockCacheEntrySize = 100 * 1000 * 1000;
// We can override the test mode for a given operation by setting this global
// variable.
int g_test_mode = 0;
int GetTestModeForEntry(const std::string& key) {
// 'key' is prefixed with an identifier if it corresponds to a cached POST.
// Skip past that to locate the actual URL.
//
// TODO(darin): It breaks the abstraction a bit that we assume 'key' is an
// URL corresponding to a registered MockTransaction. It would be good to
// have another way to access the test_mode.
GURL url;
if (isdigit(key[0])) {
size_t slash = key.find('/');
DCHECK(slash != std::string::npos);
url = GURL(key.substr(slash + 1));
} else {
url = GURL(key);
}
const MockTransaction* t = FindMockTransaction(url);
DCHECK(t);
return t->test_mode;
}
} // namespace
//-----------------------------------------------------------------------------
struct MockDiskEntry::CallbackInfo {
scoped_refptr<MockDiskEntry> entry;
net::CompletionOnceCallback callback;
int result;
};
MockDiskEntry::MockDiskEntry(const std::string& key)
: key_(key),
in_memory_data_(0),
doomed_(false),
sparse_(false),
fail_requests_(false),
fail_sparse_requests_(false),
busy_(false),
delayed_(false),
cancel_(false),
defer_op_(DEFER_NONE),
resume_return_code_(0) {
test_mode_ = GetTestModeForEntry(key);
}
void MockDiskEntry::Doom() {
doomed_ = true;
}
void MockDiskEntry::Close() {
Release();
}
std::string MockDiskEntry::GetKey() const {
return key_;
}
base::Time MockDiskEntry::GetLastUsed() const {
return base::Time::Now();
}
base::Time MockDiskEntry::GetLastModified() const {
return base::Time::Now();
}
int32_t MockDiskEntry::GetDataSize(int index) const {
DCHECK(index >= 0 && index < kNumCacheEntryDataIndices);
return static_cast<int32_t>(data_[index].size());
}
int MockDiskEntry::ReadData(int index,
int offset,
IOBuffer* buf,
int buf_len,
CompletionOnceCallback callback) {
DCHECK(index >= 0 && index < kNumCacheEntryDataIndices);
DCHECK(!callback.is_null());
if (fail_requests_)
return ERR_CACHE_READ_FAILURE;
if (offset < 0 || offset > static_cast<int>(data_[index].size()))
return ERR_FAILED;
if (static_cast<size_t>(offset) == data_[index].size())
return 0;
int num = std::min(buf_len, static_cast<int>(data_[index].size()) - offset);
SbMemoryCopy(buf->data(), &data_[index][offset], num);
if (MockHttpCache::GetTestMode(test_mode_) & TEST_MODE_SYNC_CACHE_READ)
return num;
// Pause and resume.
if (defer_op_ == DEFER_READ) {
defer_op_ = DEFER_NONE;
resume_callback_ = std::move(callback);
resume_return_code_ = num;
return ERR_IO_PENDING;
}
CallbackLater(std::move(callback), num);
return ERR_IO_PENDING;
}
void MockDiskEntry::ResumeDiskEntryOperation() {
DCHECK(!resume_callback_.is_null());
CallbackLater(std::move(resume_callback_), resume_return_code_);
resume_return_code_ = 0;
}
int MockDiskEntry::WriteData(int index,
int offset,
IOBuffer* buf,
int buf_len,
CompletionOnceCallback callback,
bool truncate) {
DCHECK(index >= 0 && index < kNumCacheEntryDataIndices);
DCHECK(!callback.is_null());
DCHECK(truncate);
if (fail_requests_) {
CallbackLater(std::move(callback), ERR_CACHE_READ_FAILURE);
return ERR_IO_PENDING;
}
if (offset < 0 || offset > static_cast<int>(data_[index].size()))
return ERR_FAILED;
DCHECK_LT(offset + buf_len, kMaxMockCacheEntrySize);
data_[index].resize(offset + buf_len);
if (buf_len)
SbMemoryCopy(&data_[index][offset], buf->data(), buf_len);
if (MockHttpCache::GetTestMode(test_mode_) & TEST_MODE_SYNC_CACHE_WRITE)
return buf_len;
if (defer_op_ == DEFER_WRITE) {
defer_op_ = DEFER_NONE;
resume_callback_ = std::move(callback);
resume_return_code_ = buf_len;
return ERR_IO_PENDING;
}
CallbackLater(std::move(callback), buf_len);
return ERR_IO_PENDING;
}
int MockDiskEntry::ReadSparseData(int64_t offset,
IOBuffer* buf,
int buf_len,
CompletionOnceCallback callback) {
DCHECK(!callback.is_null());
if (fail_sparse_requests_)
return ERR_NOT_IMPLEMENTED;
if (!sparse_ || busy_ || cancel_)
return ERR_CACHE_OPERATION_NOT_SUPPORTED;
if (offset < 0)
return ERR_FAILED;
if (fail_requests_)
return ERR_CACHE_READ_FAILURE;
DCHECK(offset < std::numeric_limits<int32_t>::max());
int real_offset = static_cast<int>(offset);
if (!buf_len)
return 0;
int num = std::min(static_cast<int>(data_[1].size()) - real_offset,
buf_len);
SbMemoryCopy(buf->data(), &data_[1][real_offset], num);
if (MockHttpCache::GetTestMode(test_mode_) & TEST_MODE_SYNC_CACHE_READ)
return num;
CallbackLater(std::move(callback), num);
busy_ = true;
delayed_ = false;
return ERR_IO_PENDING;
}
int MockDiskEntry::WriteSparseData(int64_t offset,
IOBuffer* buf,
int buf_len,
CompletionOnceCallback callback) {
DCHECK(!callback.is_null());
if (fail_sparse_requests_)
return ERR_NOT_IMPLEMENTED;
if (busy_ || cancel_)
return ERR_CACHE_OPERATION_NOT_SUPPORTED;
if (!sparse_) {
if (data_[1].size())
return ERR_CACHE_OPERATION_NOT_SUPPORTED;
sparse_ = true;
}
if (offset < 0)
return ERR_FAILED;
if (!buf_len)
return 0;
if (fail_requests_)
return ERR_CACHE_READ_FAILURE;
DCHECK(offset < std::numeric_limits<int32_t>::max());
int real_offset = static_cast<int>(offset);
if (static_cast<int>(data_[1].size()) < real_offset + buf_len) {
DCHECK_LT(real_offset + buf_len, kMaxMockCacheEntrySize);
data_[1].resize(real_offset + buf_len);
}
SbMemoryCopy(&data_[1][real_offset], buf->data(), buf_len);
if (MockHttpCache::GetTestMode(test_mode_) & TEST_MODE_SYNC_CACHE_WRITE)
return buf_len;
CallbackLater(std::move(callback), buf_len);
return ERR_IO_PENDING;
}
int MockDiskEntry::GetAvailableRange(int64_t offset,
int len,
int64_t* start,
CompletionOnceCallback callback) {
DCHECK(!callback.is_null());
if (!sparse_ || busy_ || cancel_)
return ERR_CACHE_OPERATION_NOT_SUPPORTED;
if (offset < 0)
return ERR_FAILED;
if (fail_requests_)
return ERR_CACHE_READ_FAILURE;
*start = offset;
DCHECK(offset < std::numeric_limits<int32_t>::max());
int real_offset = static_cast<int>(offset);
if (static_cast<int>(data_[1].size()) < real_offset)
return 0;
int num = std::min(static_cast<int>(data_[1].size()) - real_offset, len);
int count = 0;
for (; num > 0; num--, real_offset++) {
if (!count) {
if (data_[1][real_offset]) {
count++;
*start = real_offset;
}
} else {
if (!data_[1][real_offset])
break;
count++;
}
}
if (MockHttpCache::GetTestMode(test_mode_) & TEST_MODE_SYNC_CACHE_WRITE)
return count;
CallbackLater(std::move(callback), count);
return ERR_IO_PENDING;
}
bool MockDiskEntry::CouldBeSparse() const {
if (fail_sparse_requests_)
return false;
return sparse_;
}
void MockDiskEntry::CancelSparseIO() {
cancel_ = true;
}
net::Error MockDiskEntry::ReadyForSparseIO(CompletionOnceCallback callback) {
if (fail_sparse_requests_)
return ERR_NOT_IMPLEMENTED;
if (!cancel_)
return OK;
cancel_ = false;
DCHECK(!callback.is_null());
if (MockHttpCache::GetTestMode(test_mode_) & TEST_MODE_SYNC_CACHE_READ)
return OK;
// The pending operation is already in the message loop (and hopefully
// already in the second pass). Just notify the caller that it finished.
CallbackLater(std::move(callback), 0);
return ERR_IO_PENDING;
}
void MockDiskEntry::SetLastUsedTimeForTest(base::Time time) {
NOTREACHED();
}
// If |value| is true, don't deliver any completion callbacks until called
// again with |value| set to false. Caution: remember to enable callbacks
// again or all subsequent tests will fail.
// Static.
void MockDiskEntry::IgnoreCallbacks(bool value) {
if (ignore_callbacks_ == value)
return;
ignore_callbacks_ = value;
if (!value)
StoreAndDeliverCallbacks(false, NULL, CompletionOnceCallback(), 0);
}
MockDiskEntry::~MockDiskEntry() = default;
// Unlike the callbacks for MockHttpTransaction, we want this one to run even
// if the consumer called Close on the MockDiskEntry. We achieve that by
// leveraging the fact that this class is reference counted.
void MockDiskEntry::CallbackLater(CompletionOnceCallback callback, int result) {
if (ignore_callbacks_)
return StoreAndDeliverCallbacks(true, this, std::move(callback), result);
base::ThreadTaskRunnerHandle::Get()->PostTask(
FROM_HERE, base::BindOnce(&MockDiskEntry::RunCallback, this,
std::move(callback), result));
}
void MockDiskEntry::RunCallback(CompletionOnceCallback callback, int result) {
if (busy_) {
// This is kind of hacky, but controlling the behavior of just this entry
// from a test is sort of complicated. What we really want to do is
// delay the delivery of a sparse IO operation a little more so that the
// request start operation (async) will finish without seeing the end of
// this operation (already posted to the message loop)... and without
// just delaying for n mS (which may cause trouble with slow bots). So
// we re-post this operation (all async sparse IO operations will take two
// trips through the message loop instead of one).
if (!delayed_) {
delayed_ = true;
return CallbackLater(std::move(callback), result);
}
}
busy_ = false;
std::move(callback).Run(result);
}
// When |store| is true, stores the callback to be delivered later; otherwise
// delivers any callback previously stored.
// Static.
void MockDiskEntry::StoreAndDeliverCallbacks(bool store,
MockDiskEntry* entry,
CompletionOnceCallback callback,
int result) {
static std::vector<CallbackInfo> callback_list;
if (store) {
CallbackInfo c = {entry, std::move(callback), result};
callback_list.push_back(std::move(c));
} else {
for (size_t i = 0; i < callback_list.size(); i++) {
CallbackInfo& c = callback_list[i];
c.entry->CallbackLater(std::move(c.callback), c.result);
}
callback_list.clear();
}
}
// Statics.
bool MockDiskEntry::ignore_callbacks_ = false;
//-----------------------------------------------------------------------------
MockDiskCache::MockDiskCache()
: open_count_(0),
create_count_(0),
doomed_count_(0),
fail_requests_(false),
soft_failures_(false),
double_create_check_(true),
fail_sparse_requests_(false),
support_in_memory_entry_data_(true),
defer_op_(MockDiskEntry::DEFER_NONE),
resume_return_code_(0) {}
MockDiskCache::~MockDiskCache() {
ReleaseAll();
}
CacheType MockDiskCache::GetCacheType() const {
return DISK_CACHE;
}
int32_t MockDiskCache::GetEntryCount() const {
return static_cast<int32_t>(entries_.size());
}
net::Error MockDiskCache::OpenEntry(const std::string& key,
net::RequestPriority request_priority,
disk_cache::Entry** entry,
CompletionOnceCallback callback) {
DCHECK(!callback.is_null());
if (fail_requests_)
return ERR_CACHE_OPEN_FAILURE;
auto it = entries_.find(key);
if (it == entries_.end())
return ERR_CACHE_OPEN_FAILURE;
if (it->second->is_doomed()) {
it->second->Release();
entries_.erase(it);
return ERR_CACHE_OPEN_FAILURE;
}
open_count_++;
it->second->AddRef();
*entry = it->second;
if (soft_failures_)
it->second->set_fail_requests();
if (GetTestModeForEntry(key) & TEST_MODE_SYNC_CACHE_START)
return OK;
CallbackLater(std::move(callback), OK);
return ERR_IO_PENDING;
}
net::Error MockDiskCache::CreateEntry(const std::string& key,
net::RequestPriority request_priority,
disk_cache::Entry** entry,
CompletionOnceCallback callback) {
DCHECK(!callback.is_null());
if (fail_requests_)
return ERR_CACHE_CREATE_FAILURE;
auto it = entries_.find(key);
if (it != entries_.end()) {
if (!it->second->is_doomed()) {
if (double_create_check_)
NOTREACHED();
else
return ERR_CACHE_CREATE_FAILURE;
}
it->second->Release();
entries_.erase(it);
}
create_count_++;
MockDiskEntry* new_entry = new MockDiskEntry(key);
new_entry->AddRef();
entries_[key] = new_entry;
new_entry->AddRef();
*entry = new_entry;
if (soft_failures_)
new_entry->set_fail_requests();
if (fail_sparse_requests_)
new_entry->set_fail_sparse_requests();
if (GetTestModeForEntry(key) & TEST_MODE_SYNC_CACHE_START)
return OK;
// Pause and resume.
if (defer_op_ == MockDiskEntry::DEFER_CREATE) {
defer_op_ = MockDiskEntry::DEFER_NONE;
resume_callback_ = std::move(callback);
resume_return_code_ = OK;
return ERR_IO_PENDING;
}
CallbackLater(std::move(callback), OK);
return ERR_IO_PENDING;
}
net::Error MockDiskCache::DoomEntry(const std::string& key,
net::RequestPriority request_priority,
CompletionOnceCallback callback) {
DCHECK(!callback.is_null());
auto it = entries_.find(key);
if (it != entries_.end()) {
it->second->Release();
entries_.erase(it);
doomed_count_++;
}
if (GetTestModeForEntry(key) & TEST_MODE_SYNC_CACHE_START)
return OK;
CallbackLater(std::move(callback), OK);
return ERR_IO_PENDING;
}
net::Error MockDiskCache::DoomAllEntries(CompletionOnceCallback callback) {
return ERR_NOT_IMPLEMENTED;
}
net::Error MockDiskCache::DoomEntriesBetween(const base::Time initial_time,
const base::Time end_time,
CompletionOnceCallback callback) {
return ERR_NOT_IMPLEMENTED;
}
net::Error MockDiskCache::DoomEntriesSince(const base::Time initial_time,
CompletionOnceCallback callback) {
return ERR_NOT_IMPLEMENTED;
}
int64_t MockDiskCache::CalculateSizeOfAllEntries(
Int64CompletionOnceCallback callback) {
return ERR_NOT_IMPLEMENTED;
}
class MockDiskCache::NotImplementedIterator : public Iterator {
public:
net::Error OpenNextEntry(disk_cache::Entry** next_entry,
CompletionOnceCallback callback) override {
return ERR_NOT_IMPLEMENTED;
}
};
std::unique_ptr<disk_cache::Backend::Iterator> MockDiskCache::CreateIterator() {
return std::unique_ptr<Iterator>(new NotImplementedIterator());
}
void MockDiskCache::GetStats(base::StringPairs* stats) {
}
void MockDiskCache::OnExternalCacheHit(const std::string& key) {
}
size_t MockDiskCache::DumpMemoryStats(
base::trace_event::ProcessMemoryDump* pmd,
const std::string& parent_absolute_name) const {
return 0u;
}
uint8_t MockDiskCache::GetEntryInMemoryData(const std::string& key) {
if (!support_in_memory_entry_data_)
return 0;
auto it = entries_.find(key);
if (it != entries_.end())
return it->second->in_memory_data();
return 0;
}
void MockDiskCache::SetEntryInMemoryData(const std::string& key, uint8_t data) {
auto it = entries_.find(key);
if (it != entries_.end())
it->second->set_in_memory_data(data);
}
void MockDiskCache::ReleaseAll() {
for (auto entry : entries_)
entry.second->Release();
entries_.clear();
}
void MockDiskCache::CallbackLater(CompletionOnceCallback callback, int result) {
base::ThreadTaskRunnerHandle::Get()->PostTask(
FROM_HERE, base::BindOnce(std::move(callback), result));
}
bool MockDiskCache::IsDiskEntryDoomed(const std::string& key) {
auto it = entries_.find(key);
if (it != entries_.end())
return it->second->is_doomed();
return false;
}
void MockDiskCache::ResumeCacheOperation() {
DCHECK(!resume_callback_.is_null());
CallbackLater(std::move(resume_callback_), resume_return_code_);
resume_return_code_ = 0;
}
scoped_refptr<MockDiskEntry> MockDiskCache::GetDiskEntryRef(
const std::string& key) {
auto it = entries_.find(key);
if (it == entries_.end())
return nullptr;
return it->second;
}
//-----------------------------------------------------------------------------
int MockBackendFactory::CreateBackend(
NetLog* net_log,
std::unique_ptr<disk_cache::Backend>* backend,
CompletionOnceCallback callback) {
backend->reset(new MockDiskCache());
return OK;
}
//-----------------------------------------------------------------------------
MockHttpCache::MockHttpCache() : MockHttpCache(false) {}
MockHttpCache::MockHttpCache(
std::unique_ptr<HttpCache::BackendFactory> disk_cache_factory)
: MockHttpCache(std::move(disk_cache_factory), false) {}
MockHttpCache::MockHttpCache(bool is_main_cache)
: MockHttpCache(std::make_unique<MockBackendFactory>(), is_main_cache) {}
MockHttpCache::MockHttpCache(
std::unique_ptr<HttpCache::BackendFactory> disk_cache_factory,
bool is_main_cache)
: http_cache_(std::make_unique<MockNetworkLayer>(),
std::move(disk_cache_factory),
is_main_cache) {}
disk_cache::Backend* MockHttpCache::backend() {
TestCompletionCallback cb;
disk_cache::Backend* backend;
int rv = http_cache_.GetBackend(&backend, cb.callback());
rv = cb.GetResult(rv);
return (rv == OK) ? backend : NULL;
}
MockDiskCache* MockHttpCache::disk_cache() {
return static_cast<MockDiskCache*>(backend());
}
int MockHttpCache::CreateTransaction(std::unique_ptr<HttpTransaction>* trans) {
return http_cache_.CreateTransaction(DEFAULT_PRIORITY, trans);
}
void MockHttpCache::SimulateCacheLockTimeout() {
http_cache_.SimulateCacheLockTimeoutForTesting();
}
void MockHttpCache::SimulateCacheLockTimeoutAfterHeaders() {
http_cache_.SimulateCacheLockTimeoutAfterHeadersForTesting();
}
void MockHttpCache::FailConditionalizations() {
http_cache_.FailConditionalizationForTest();
}
bool MockHttpCache::ReadResponseInfo(disk_cache::Entry* disk_entry,
HttpResponseInfo* response_info,
bool* response_truncated) {
int size = disk_entry->GetDataSize(0);
TestCompletionCallback cb;
scoped_refptr<IOBuffer> buffer = base::MakeRefCounted<IOBuffer>(size);
int rv = disk_entry->ReadData(0, 0, buffer.get(), size, cb.callback());
rv = cb.GetResult(rv);
EXPECT_EQ(size, rv);
return HttpCache::ParseResponseInfo(buffer->data(), size, response_info,
response_truncated);
}
bool MockHttpCache::WriteResponseInfo(disk_cache::Entry* disk_entry,
const HttpResponseInfo* response_info,
bool skip_transient_headers,
bool response_truncated) {
base::Pickle pickle;
response_info->Persist(
&pickle, skip_transient_headers, response_truncated);
TestCompletionCallback cb;
scoped_refptr<WrappedIOBuffer> data = base::MakeRefCounted<WrappedIOBuffer>(
reinterpret_cast<const char*>(pickle.data()));
int len = static_cast<int>(pickle.size());
int rv = disk_entry->WriteData(0, 0, data.get(), len, cb.callback(), true);
rv = cb.GetResult(rv);
return (rv == len);
}
bool MockHttpCache::OpenBackendEntry(const std::string& key,
disk_cache::Entry** entry) {
TestCompletionCallback cb;
int rv = backend()->OpenEntry(key, net::HIGHEST, entry, cb.callback());
return (cb.GetResult(rv) == OK);
}
bool MockHttpCache::CreateBackendEntry(const std::string& key,
disk_cache::Entry** entry,
NetLog* net_log) {
TestCompletionCallback cb;
int rv = backend()->CreateEntry(key, net::HIGHEST, entry, cb.callback());
return (cb.GetResult(rv) == OK);
}
// Static.
int MockHttpCache::GetTestMode(int test_mode) {
if (!g_test_mode)
return test_mode;
return g_test_mode;
}
// Static.
void MockHttpCache::SetTestMode(int test_mode) {
g_test_mode = test_mode;
}
bool MockHttpCache::IsWriterPresent(const std::string& key) {
HttpCache::ActiveEntry* entry = http_cache_.FindActiveEntry(key);
return entry && entry->writers && !entry->writers->IsEmpty();
}
bool MockHttpCache::IsHeadersTransactionPresent(const std::string& key) {
HttpCache::ActiveEntry* entry = http_cache_.FindActiveEntry(key);
return entry && entry->headers_transaction;
}
int MockHttpCache::GetCountReaders(const std::string& key) {
HttpCache::ActiveEntry* entry = http_cache_.FindActiveEntry(key);
return entry ? entry->readers.size() : 0;
}
int MockHttpCache::GetCountAddToEntryQueue(const std::string& key) {
HttpCache::ActiveEntry* entry = http_cache_.FindActiveEntry(key);
return entry ? entry->add_to_entry_queue.size() : 0;
}
int MockHttpCache::GetCountDoneHeadersQueue(const std::string& key) {
HttpCache::ActiveEntry* entry = http_cache_.FindActiveEntry(key);
return entry ? entry->done_headers_queue.size() : 0;
}
int MockHttpCache::GetCountWriterTransactions(const std::string& key) {
HttpCache::ActiveEntry* entry = http_cache_.FindActiveEntry(key);
return entry && entry->writers ? entry->writers->GetTransactionsCount() : 0;
}
//-----------------------------------------------------------------------------
net::Error MockDiskCacheNoCB::CreateEntry(const std::string& key,
net::RequestPriority request_priority,
disk_cache::Entry** entry,
CompletionOnceCallback callback) {
return ERR_IO_PENDING;
}
//-----------------------------------------------------------------------------
int MockBackendNoCbFactory::CreateBackend(
NetLog* net_log,
std::unique_ptr<disk_cache::Backend>* backend,
CompletionOnceCallback callback) {
backend->reset(new MockDiskCacheNoCB());
return OK;
}
//-----------------------------------------------------------------------------
MockBlockingBackendFactory::MockBlockingBackendFactory()
: backend_(NULL),
block_(true),
fail_(false) {
}
MockBlockingBackendFactory::~MockBlockingBackendFactory() = default;
int MockBlockingBackendFactory::CreateBackend(
NetLog* net_log,
std::unique_ptr<disk_cache::Backend>* backend,
CompletionOnceCallback callback) {
if (!block_) {
if (!fail_)
backend->reset(new MockDiskCache());
return Result();
}
backend_ = backend;
callback_ = std::move(callback);
return ERR_IO_PENDING;
}
void MockBlockingBackendFactory::FinishCreation() {
block_ = false;
if (!callback_.is_null()) {
if (!fail_)
backend_->reset(new MockDiskCache());
// Running the callback might delete |this|.
base::ResetAndReturn(&callback_).Run(Result());
}
}
} // namespace net