blob: 8b20caa4948019e73cd39541f9fe6af4e06a7fa1 [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/http_cache_transaction.h"
#include "build/build_config.h" // For OS_POSIX
#if defined(OS_POSIX)
#include <unistd.h>
#endif
#include <algorithm>
#include <string>
#include <utility>
#include "base/auto_reset.h"
#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/callback_helpers.h"
#include "base/compiler_specific.h"
#include "base/format_macros.h"
#include "base/location.h"
#include "base/metrics/histogram_functions.h"
#include "base/metrics/histogram_macros.h"
#include "base/single_thread_task_runner.h"
#include "base/stl_util.h"
#include "base/strings/string_number_conversions.h" // For HexEncode.
#include "base/strings/string_piece.h"
#include "base/strings/string_util.h" // For LowerCaseEqualsASCII.
#include "base/strings/stringprintf.h"
#include "base/threading/thread_task_runner_handle.h"
#include "base/time/clock.h"
#include "base/trace_event/trace_event.h"
#include "base/values.h"
#include "net/base/auth.h"
#include "net/base/features.h"
#include "net/base/load_flags.h"
#include "net/base/load_timing_info.h"
#include "net/base/trace_constants.h"
#include "net/base/upload_data_stream.h"
#include "net/cert/cert_status_flags.h"
#include "net/cert/x509_certificate.h"
#include "net/disk_cache/disk_cache.h"
#include "net/http/http_cache_writers.h"
#include "net/http/http_network_session.h"
#include "net/http/http_request_info.h"
#include "net/http/http_util.h"
#include "net/log/net_log_event_type.h"
#include "net/ssl/ssl_cert_request_info.h"
#include "net/ssl/ssl_config_service.h"
using base::Time;
using base::TimeDelta;
using base::TimeTicks;
namespace net {
using CacheEntryStatus = HttpResponseInfo::CacheEntryStatus;
namespace {
constexpr TimeDelta kStaleRevalidateTimeout = TimeDelta::FromSeconds(60);
// From http://tools.ietf.org/html/draft-ietf-httpbis-p6-cache-21#section-6
// a "non-error response" is one with a 2xx (Successful) or 3xx
// (Redirection) status code.
bool NonErrorResponse(int status_code) {
int status_code_range = status_code / 100;
return status_code_range == 2 || status_code_range == 3;
}
void RecordNoStoreHeaderHistogram(int load_flags,
const HttpResponseInfo* response) {
if (load_flags & LOAD_MAIN_FRAME_DEPRECATED) {
UMA_HISTOGRAM_BOOLEAN(
"Net.MainFrameNoStore",
response->headers->HasHeaderValue("cache-control", "no-store"));
}
}
enum ExternallyConditionalizedType {
EXTERNALLY_CONDITIONALIZED_CACHE_REQUIRES_VALIDATION,
EXTERNALLY_CONDITIONALIZED_CACHE_USABLE,
EXTERNALLY_CONDITIONALIZED_MISMATCHED_VALIDATORS,
EXTERNALLY_CONDITIONALIZED_MAX
};
} // namespace
#define CACHE_STATUS_HISTOGRAMS(type) \
do { \
UMA_HISTOGRAM_ENUMERATION("HttpCache.Pattern" type, cache_entry_status_, \
CacheEntryStatus::ENTRY_MAX); \
if (validation_request) { \
UMA_HISTOGRAM_ENUMERATION("HttpCache.ValidationCause" type, \
validation_cause_, VALIDATION_CAUSE_MAX); \
} \
if (stale_request) { \
UMA_HISTOGRAM_COUNTS_1M( \
"HttpCache.StaleEntry.FreshnessPeriodsSinceLastUsed" type, \
freshness_periods_since_last_used); \
} \
} while (0)
struct HeaderNameAndValue {
const char* name;
const char* value;
};
// If the request includes one of these request headers, then avoid caching
// to avoid getting confused.
static const HeaderNameAndValue kPassThroughHeaders[] = {
{ "if-unmodified-since", NULL }, // causes unexpected 412s
{ "if-match", NULL }, // causes unexpected 412s
{ "if-range", NULL },
{ NULL, NULL }
};
struct ValidationHeaderInfo {
const char* request_header_name;
const char* related_response_header_name;
};
static const ValidationHeaderInfo kValidationHeaders[] = {
{ "if-modified-since", "last-modified" },
{ "if-none-match", "etag" },
};
// If the request includes one of these request headers, then avoid reusing
// our cached copy if any.
static const HeaderNameAndValue kForceFetchHeaders[] = {
{ "cache-control", "no-cache" },
{ "pragma", "no-cache" },
{ NULL, NULL }
};
// If the request includes one of these request headers, then force our
// cached copy (if any) to be revalidated before reusing it.
static const HeaderNameAndValue kForceValidateHeaders[] = {
{ "cache-control", "max-age=0" },
{ NULL, NULL }
};
static bool HeaderMatches(const HttpRequestHeaders& headers,
const HeaderNameAndValue* search) {
for (; search->name; ++search) {
std::string header_value;
if (!headers.GetHeader(search->name, &header_value))
continue;
if (!search->value)
return true;
HttpUtil::ValuesIterator v(header_value.begin(), header_value.end(), ',');
while (v.GetNext()) {
if (base::LowerCaseEqualsASCII(
base::StringPiece(v.value_begin(), v.value_end()), search->value))
return true;
}
}
return false;
}
//-----------------------------------------------------------------------------
HttpCache::Transaction::Transaction(RequestPriority priority, HttpCache* cache)
: next_state_(STATE_NONE),
initial_request_(nullptr),
request_(NULL),
priority_(priority),
cache_(cache->GetWeakPtr()),
entry_(NULL),
new_entry_(NULL),
new_response_(NULL),
mode_(NONE),
reading_(false),
invalid_range_(false),
truncated_(false),
is_sparse_(false),
range_requested_(false),
handling_206_(false),
cache_pending_(false),
done_headers_create_new_entry_(false),
vary_mismatch_(false),
couldnt_conditionalize_request_(false),
bypass_lock_for_test_(false),
bypass_lock_after_headers_for_test_(false),
fail_conditionalization_for_test_(false),
io_buf_len_(0),
read_offset_(0),
effective_load_flags_(0),
shared_writing_error_(OK),
cache_entry_status_(CacheEntryStatus::ENTRY_UNDEFINED),
validation_cause_(VALIDATION_CAUSE_UNDEFINED),
cant_conditionalize_zero_freshness_from_memhint_(false),
recorded_histograms_(false),
parallel_writing_pattern_(PARALLEL_WRITING_NONE),
moved_network_transaction_to_writers_(false),
websocket_handshake_stream_base_create_helper_(NULL),
in_do_loop_(false),
weak_factory_(this) {
TRACE_EVENT0("io", "HttpCacheTransaction::Transaction");
static_assert(HttpCache::Transaction::kNumValidationHeaders ==
base::size(kValidationHeaders),
"invalid number of validation headers");
io_callback_ = base::BindRepeating(&Transaction::OnIOComplete,
weak_factory_.GetWeakPtr());
}
HttpCache::Transaction::~Transaction() {
TRACE_EVENT0("io", "HttpCacheTransaction::~Transaction");
// We may have to issue another IO, but we should never invoke the callback_
// after this point.
callback_.Reset();
if (cache_) {
if (entry_) {
DoneWithEntry(false /* entry_is_complete */);
} else if (cache_pending_) {
cache_->RemovePendingTransaction(this);
}
}
}
HttpCache::Transaction::Mode HttpCache::Transaction::mode() const {
return mode_;
}
int HttpCache::Transaction::WriteMetadata(IOBuffer* buf,
int buf_len,
CompletionOnceCallback callback) {
DCHECK(buf);
DCHECK_GT(buf_len, 0);
DCHECK(!callback.is_null());
if (!cache_.get() || !entry_)
return ERR_UNEXPECTED;
// We don't need to track this operation for anything.
// It could be possible to check if there is something already written and
// avoid writing again (it should be the same, right?), but let's allow the
// caller to "update" the contents with something new.
return entry_->disk_entry->WriteData(kMetadataIndex, 0, buf, buf_len,
std::move(callback), true);
}
LoadState HttpCache::Transaction::GetWriterLoadState() const {
const HttpTransaction* transaction = network_transaction();
if (transaction)
return transaction->GetLoadState();
if (entry_ || !request_)
return LOAD_STATE_IDLE;
return LOAD_STATE_WAITING_FOR_CACHE;
}
const NetLogWithSource& HttpCache::Transaction::net_log() const {
return net_log_;
}
int HttpCache::Transaction::Start(const HttpRequestInfo* request,
CompletionOnceCallback callback,
const NetLogWithSource& net_log) {
DCHECK(request);
DCHECK(!callback.is_null());
// Ensure that we only have one asynchronous call at a time.
DCHECK(callback_.is_null());
DCHECK(!reading_);
DCHECK(!network_trans_.get());
DCHECK(!entry_);
DCHECK_EQ(next_state_, STATE_NONE);
if (!cache_.get())
return ERR_UNEXPECTED;
initial_request_ = request;
SetRequest(net_log);
// We have to wait until the backend is initialized so we start the SM.
next_state_ = STATE_GET_BACKEND;
int rv = DoLoop(OK);
// Setting this here allows us to check for the existence of a callback_ to
// determine if we are still inside Start.
if (rv == ERR_IO_PENDING)
callback_ = std::move(callback);
return rv;
}
int HttpCache::Transaction::RestartIgnoringLastError(
CompletionOnceCallback callback) {
DCHECK(!callback.is_null());
// Ensure that we only have one asynchronous call at a time.
DCHECK(callback_.is_null());
if (!cache_.get())
return ERR_UNEXPECTED;
int rv = RestartNetworkRequest();
if (rv == ERR_IO_PENDING)
callback_ = std::move(callback);
return rv;
}
int HttpCache::Transaction::RestartWithCertificate(
scoped_refptr<X509Certificate> client_cert,
scoped_refptr<SSLPrivateKey> client_private_key,
CompletionOnceCallback callback) {
DCHECK(!callback.is_null());
// Ensure that we only have one asynchronous call at a time.
DCHECK(callback_.is_null());
if (!cache_.get())
return ERR_UNEXPECTED;
int rv = RestartNetworkRequestWithCertificate(std::move(client_cert),
std::move(client_private_key));
if (rv == ERR_IO_PENDING)
callback_ = std::move(callback);
return rv;
}
int HttpCache::Transaction::RestartWithAuth(const AuthCredentials& credentials,
CompletionOnceCallback callback) {
DCHECK(auth_response_.headers.get());
DCHECK(!callback.is_null());
// Ensure that we only have one asynchronous call at a time.
DCHECK(callback_.is_null());
if (!cache_.get())
return ERR_UNEXPECTED;
// Clear the intermediate response since we are going to start over.
SetAuthResponse(HttpResponseInfo());
int rv = RestartNetworkRequestWithAuth(credentials);
if (rv == ERR_IO_PENDING)
callback_ = std::move(callback);
return rv;
}
bool HttpCache::Transaction::IsReadyToRestartForAuth() {
if (!network_trans_.get())
return false;
return network_trans_->IsReadyToRestartForAuth();
}
int HttpCache::Transaction::Read(IOBuffer* buf,
int buf_len,
CompletionOnceCallback callback) {
DCHECK_EQ(next_state_, STATE_NONE);
DCHECK(buf);
DCHECK_GT(buf_len, 0);
DCHECK(!callback.is_null());
DCHECK(callback_.is_null());
if (!cache_.get())
return ERR_UNEXPECTED;
// If we have an intermediate auth response at this point, then it means the
// user wishes to read the network response (the error page). If there is a
// previous response in the cache then we should leave it intact.
if (auth_response_.headers.get() && mode_ != NONE) {
UpdateCacheEntryStatus(CacheEntryStatus::ENTRY_OTHER);
DCHECK(mode_ & WRITE);
bool stopped = StopCachingImpl(mode_ == READ_WRITE);
DCHECK(stopped);
}
reading_ = true;
read_buf_ = buf;
io_buf_len_ = buf_len;
int rv = TransitionToReadingState();
if (rv != OK || next_state_ == STATE_NONE)
return rv;
rv = DoLoop(OK);
if (rv == ERR_IO_PENDING) {
DCHECK(callback_.is_null());
callback_ = std::move(callback);
}
return rv;
}
int HttpCache::Transaction::TransitionToReadingState() {
if (!entry_) {
if (network_trans_) {
// This can happen when the request should be handled exclusively by
// the network layer (skipping the cache entirely using
// LOAD_DISABLE_CACHE) or there was an error during the headers phase
// due to which the transaction cannot write to the cache or the consumer
// is reading the auth response from the network.
// TODO(http://crbug.com/740947) to get rid of this state in future.
next_state_ = STATE_NETWORK_READ;
return OK;
}
// If there is no network, and no cache entry, then there is nothing to read
// from.
next_state_ = STATE_NONE;
// An error state should be set for the next read, else this transaction
// should have been terminated once it reached this state. To assert we
// could dcheck that shared_writing_error_ is set to a valid error value but
// in some specific conditions (http://crbug.com/806344) it's possible that
// the consumer does an extra Read in which case the assert will fail.
return shared_writing_error_;
}
// If entry_ is present, the transaction is either a member of entry_->writers
// or readers.
if (!InWriters()) {
// Since transaction is not a writer and we are in Read(), it must be a
// reader.
DCHECK(entry_->TransactionInReaders(this));
DCHECK(mode_ == READ || (mode_ == READ_WRITE && partial_));
next_state_ = STATE_CACHE_READ_DATA;
return OK;
}
DCHECK(mode_ & WRITE || mode_ == NONE);
// If it's a writer and it is partial then it may need to read from the cache
// or from the network based on whether network transaction is present or not.
if (partial_) {
if (entry_->writers->network_transaction())
next_state_ = STATE_NETWORK_READ_CACHE_WRITE;
else
next_state_ = STATE_CACHE_READ_DATA;
return OK;
}
// Full request.
// If it's a writer and a full request then it may read from the cache if its
// offset is behind the current offset else from the network.
int disk_entry_size = entry_->disk_entry->GetDataSize(kResponseContentIndex);
if (read_offset_ == disk_entry_size || entry_->writers->network_read_only()) {
next_state_ = STATE_NETWORK_READ_CACHE_WRITE;
} else {
DCHECK_LT(read_offset_, disk_entry_size);
next_state_ = STATE_CACHE_READ_DATA;
}
return OK;
}
void HttpCache::Transaction::StopCaching() {
// We really don't know where we are now. Hopefully there is no operation in
// progress, but nothing really prevents this method to be called after we
// returned ERR_IO_PENDING. We cannot attempt to truncate the entry at this
// point because we need the state machine for that (and even if we are really
// free, that would be an asynchronous operation). In other words, keep the
// entry how it is (it will be marked as truncated at destruction), and let
// the next piece of code that executes know that we are now reading directly
// from the net.
if (cache_.get() && (mode_ & WRITE) && !is_sparse_ && !range_requested_ &&
network_transaction()) {
StopCachingImpl(false);
}
}
bool HttpCache::Transaction::GetFullRequestHeaders(
HttpRequestHeaders* headers) const {
const HttpTransaction* transaction = GetOwnedOrMovedNetworkTransaction();
if (transaction) {
return transaction->GetFullRequestHeaders(headers);
} else if (!network_transaction_info_.full_request_headers.IsEmpty()) {
*headers = network_transaction_info_.full_request_headers;
return true;
}
// TODO(juliatuttle): Read headers from cache.
return false;
}
int64_t HttpCache::Transaction::GetTotalReceivedBytes() const {
int64_t total_received_bytes = network_transaction_info_.total_received_bytes;
const HttpTransaction* transaction = GetOwnedOrMovedNetworkTransaction();
if (transaction)
total_received_bytes += transaction->GetTotalReceivedBytes();
return total_received_bytes;
}
int64_t HttpCache::Transaction::GetTotalSentBytes() const {
int64_t total_sent_bytes = network_transaction_info_.total_sent_bytes;
const HttpTransaction* transaction = GetOwnedOrMovedNetworkTransaction();
if (transaction)
total_sent_bytes += transaction->GetTotalSentBytes();
return total_sent_bytes;
}
void HttpCache::Transaction::DoneReading() {
if (cache_.get() && entry_) {
DCHECK_NE(mode_, UPDATE);
DoneWithEntry(true);
}
}
const HttpResponseInfo* HttpCache::Transaction::GetResponseInfo() const {
// Null headers means we encountered an error or haven't a response yet
if (auth_response_.headers.get()) {
DCHECK_EQ(cache_entry_status_, auth_response_.cache_entry_status)
<< "These must be in sync via SetResponse and SetAuthResponse.";
return &auth_response_;
}
DCHECK_EQ(cache_entry_status_, response_.cache_entry_status)
<< "These must be in sync via SetResponse and SetAuthResponse.";
return &response_;
}
LoadState HttpCache::Transaction::GetLoadState() const {
LoadState state = GetWriterLoadState();
if (state != LOAD_STATE_WAITING_FOR_CACHE)
return state;
if (cache_.get())
return cache_->GetLoadStateForPendingTransaction(this);
return LOAD_STATE_IDLE;
}
void HttpCache::Transaction::SetQuicServerInfo(
QuicServerInfo* quic_server_info) {}
bool HttpCache::Transaction::GetLoadTimingInfo(
LoadTimingInfo* load_timing_info) const {
const HttpTransaction* transaction = GetOwnedOrMovedNetworkTransaction();
if (transaction)
return transaction->GetLoadTimingInfo(load_timing_info);
if (network_transaction_info_.old_network_trans_load_timing) {
*load_timing_info =
*network_transaction_info_.old_network_trans_load_timing;
return true;
}
if (first_cache_access_since_.is_null())
return false;
// If the cache entry was opened, return that time.
load_timing_info->send_start = first_cache_access_since_;
// This time doesn't make much sense when reading from the cache, so just use
// the same time as send_start.
load_timing_info->send_end = first_cache_access_since_;
// Provide the time immediately before parsing a cached entry.
load_timing_info->receive_headers_start = read_headers_since_;
return true;
}
bool HttpCache::Transaction::GetRemoteEndpoint(IPEndPoint* endpoint) const {
const HttpTransaction* transaction = GetOwnedOrMovedNetworkTransaction();
if (transaction)
return transaction->GetRemoteEndpoint(endpoint);
if (!network_transaction_info_.old_remote_endpoint.address().empty()) {
*endpoint = network_transaction_info_.old_remote_endpoint;
return true;
}
return false;
}
void HttpCache::Transaction::PopulateNetErrorDetails(
NetErrorDetails* details) const {
const HttpTransaction* transaction = GetOwnedOrMovedNetworkTransaction();
if (transaction)
return transaction->PopulateNetErrorDetails(details);
return;
}
void HttpCache::Transaction::SetPriority(RequestPriority priority) {
priority_ = priority;
if (network_trans_)
network_trans_->SetPriority(priority_);
if (InWriters()) {
DCHECK(!network_trans_ || partial_);
entry_->writers->UpdatePriority();
}
}
void HttpCache::Transaction::SetWebSocketHandshakeStreamCreateHelper(
WebSocketHandshakeStreamBase::CreateHelper* create_helper) {
websocket_handshake_stream_base_create_helper_ = create_helper;
// TODO(shivanisha). Since this function must be invoked before Start() as
// per the API header, a network transaction should not exist at that point.
HttpTransaction* transaction = network_transaction();
if (transaction)
transaction->SetWebSocketHandshakeStreamCreateHelper(create_helper);
}
void HttpCache::Transaction::SetBeforeNetworkStartCallback(
const BeforeNetworkStartCallback& callback) {
DCHECK(!network_trans_);
before_network_start_callback_ = callback;
}
void HttpCache::Transaction::SetBeforeHeadersSentCallback(
const BeforeHeadersSentCallback& callback) {
DCHECK(!network_trans_);
before_headers_sent_callback_ = callback;
}
void HttpCache::Transaction::SetRequestHeadersCallback(
RequestHeadersCallback callback) {
DCHECK(!network_trans_);
request_headers_callback_ = std::move(callback);
}
void HttpCache::Transaction::SetResponseHeadersCallback(
ResponseHeadersCallback callback) {
DCHECK(!network_trans_);
response_headers_callback_ = std::move(callback);
}
int HttpCache::Transaction::ResumeNetworkStart() {
if (network_trans_)
return network_trans_->ResumeNetworkStart();
return ERR_UNEXPECTED;
}
void HttpCache::Transaction::GetConnectionAttempts(
ConnectionAttempts* out) const {
ConnectionAttempts new_connection_attempts;
const HttpTransaction* transaction = GetOwnedOrMovedNetworkTransaction();
if (transaction)
transaction->GetConnectionAttempts(&new_connection_attempts);
out->swap(new_connection_attempts);
out->insert(out->begin(),
network_transaction_info_.old_connection_attempts.begin(),
network_transaction_info_.old_connection_attempts.end());
}
void HttpCache::Transaction::SetValidatingCannotProceed() {
DCHECK(!reading_);
// Ensure this transaction is waiting for a callback.
DCHECK_NE(STATE_UNSET, next_state_);
next_state_ = STATE_HEADERS_PHASE_CANNOT_PROCEED;
entry_ = nullptr;
}
size_t HttpCache::Transaction::EstimateMemoryUsage() const {
// TODO(xunjieli): Consider improving the coverage. crbug.com/669108.
return 0;
}
void HttpCache::Transaction::WriterAboutToBeRemovedFromEntry(int result) {
RecordHistograms();
// Since the transaction can no longer access the network transaction, save
// all network related info now.
if (moved_network_transaction_to_writers_ &&
entry_->writers->network_transaction()) {
SaveNetworkTransactionInfo(*(entry_->writers->network_transaction()));
}
entry_ = nullptr;
mode_ = NONE;
// Transactions in the midst of a Read call through writers will get any error
// code through the IO callback but for idle transactions/transactions reading
// from the cache, the error for a future Read must be stored here.
if (result < 0)
shared_writing_error_ = result;
}
void HttpCache::Transaction::WriteModeTransactionAboutToBecomeReader() {
mode_ = READ;
if (moved_network_transaction_to_writers_ &&
entry_->writers->network_transaction()) {
SaveNetworkTransactionInfo(*(entry_->writers->network_transaction()));
}
}
void HttpCache::Transaction::MaybeSetParallelWritingPatternForMetrics(
HttpCache::ParallelWritingPattern pattern) {
// It's possible a transaction could not join existing writers and then
// creates a new writers. In that case the original reason for not being able
// to join writers should be logged.
if (parallel_writing_pattern_ == PARALLEL_WRITING_NONE)
parallel_writing_pattern_ = pattern;
}
//-----------------------------------------------------------------------------
// A few common patterns: (Foo* means Foo -> FooComplete)
//
// 1. Not-cached entry:
// Start():
// GetBackend* -> InitEntry -> OpenEntry* -> CreateEntry* -> AddToEntry* ->
// SendRequest* -> SuccessfulSendRequest -> OverwriteCachedResponse ->
// CacheWriteResponse* -> TruncateCachedData* -> TruncateCachedMetadata* ->
// PartialHeadersReceived -> FinishHeaders*
//
// Read():
// NetworkReadCacheWrite*/CacheReadData* (if other writers are also writing to
// the cache)
//
// 2. Cached entry, no validation:
// Start():
// GetBackend* -> InitEntry -> OpenEntry* -> AddToEntry* -> CacheReadResponse*
// -> CacheDispatchValidation -> BeginPartialCacheValidation() ->
// BeginCacheValidation() -> SetupEntryForRead() -> FinishHeaders*
//
// Read():
// CacheReadData*
//
// 3. Cached entry, validation (304):
// Start():
// GetBackend* -> InitEntry -> OpenEntry* -> AddToEntry* -> CacheReadResponse*
// -> CacheDispatchValidation -> BeginPartialCacheValidation() ->
// BeginCacheValidation() -> SendRequest* -> SuccessfulSendRequest ->
// UpdateCachedResponse -> CacheWriteUpdatedResponse* ->
// UpdateCachedResponseComplete -> OverwriteCachedResponse ->
// PartialHeadersReceived -> FinishHeaders*
//
// Read():
// CacheReadData*
//
// 4. Cached entry, validation and replace (200):
// Start():
// GetBackend* -> InitEntry -> OpenEntry* -> AddToEntry* -> CacheReadResponse*
// -> CacheDispatchValidation -> BeginPartialCacheValidation() ->
// BeginCacheValidation() -> SendRequest* -> SuccessfulSendRequest ->
// OverwriteCachedResponse -> CacheWriteResponse* -> DoTruncateCachedData* ->
// TruncateCachedMetadata* -> PartialHeadersReceived -> FinishHeaders*
//
// Read():
// NetworkReadCacheWrite*/CacheReadData* (if other writers are also writing to
// the cache)
//
// 5. Sparse entry, partially cached, byte range request:
// Start():
// GetBackend* -> InitEntry -> OpenEntry* -> AddToEntry* -> CacheReadResponse*
// -> CacheDispatchValidation -> BeginPartialCacheValidation() ->
// CacheQueryData* -> ValidateEntryHeadersAndContinue() ->
// StartPartialCacheValidation -> CompletePartialCacheValidation ->
// BeginCacheValidation() -> SendRequest* -> SuccessfulSendRequest ->
// UpdateCachedResponse -> CacheWriteUpdatedResponse* ->
// UpdateCachedResponseComplete -> OverwriteCachedResponse ->
// PartialHeadersReceived -> FinishHeaders*
//
// Read() 1:
// NetworkReadCacheWrite*
//
// Read() 2:
// NetworkReadCacheWrite* -> StartPartialCacheValidation ->
// CompletePartialCacheValidation -> CacheReadData* ->
//
// Read() 3:
// CacheReadData* -> StartPartialCacheValidation ->
// CompletePartialCacheValidation -> BeginCacheValidation() -> SendRequest* ->
// SuccessfulSendRequest -> UpdateCachedResponse* -> OverwriteCachedResponse
// -> PartialHeadersReceived -> NetworkReadCacheWrite*
//
// 6. HEAD. Not-cached entry:
// Pass through. Don't save a HEAD by itself.
// Start():
// GetBackend* -> InitEntry -> OpenEntry* -> SendRequest*
//
// 7. HEAD. Cached entry, no validation:
// Start():
// The same flow as for a GET request (example #2)
//
// Read():
// CacheReadData (returns 0)
//
// 8. HEAD. Cached entry, validation (304):
// The request updates the stored headers.
// Start(): Same as for a GET request (example #3)
//
// Read():
// CacheReadData (returns 0)
//
// 9. HEAD. Cached entry, validation and replace (200):
// Pass through. The request dooms the old entry, as a HEAD won't be stored by
// itself.
// Start():
// GetBackend* -> InitEntry -> OpenEntry* -> AddToEntry* -> CacheReadResponse*
// -> CacheDispatchValidation -> BeginPartialCacheValidation() ->
// BeginCacheValidation() -> SendRequest* -> SuccessfulSendRequest ->
// OverwriteCachedResponse -> FinishHeaders*
//
// 10. HEAD. Sparse entry, partially cached:
// Serve the request from the cache, as long as it doesn't require
// revalidation. Ignore missing ranges when deciding to revalidate. If the
// entry requires revalidation, ignore the whole request and go to full pass
// through (the result of the HEAD request will NOT update the entry).
//
// Start(): Basically the same as example 7, as we never create a partial_
// object for this request.
//
// 11. Prefetch, not-cached entry:
// The same as example 1. The "unused_since_prefetch" bit is stored as true in
// UpdateCachedResponse.
//
// 12. Prefetch, cached entry:
// Like examples 2-4, only CacheToggleUnusedSincePrefetch* is inserted between
// CacheReadResponse* and CacheDispatchValidation if the unused_since_prefetch
// bit is unset.
//
// 13. Cached entry less than 5 minutes old, unused_since_prefetch is true:
// Skip validation, similar to example 2.
// GetBackend* -> InitEntry -> OpenEntry* -> AddToEntry* -> CacheReadResponse*
// -> CacheToggleUnusedSincePrefetch* -> CacheDispatchValidation ->
// BeginPartialCacheValidation() -> BeginCacheValidation() ->
// SetupEntryForRead() -> FinishHeaders*
//
// Read():
// CacheReadData*
//
// 14. Cached entry more than 5 minutes old, unused_since_prefetch is true:
// Like examples 2-4, only CacheToggleUnusedSincePrefetch* is inserted between
// CacheReadResponse* and CacheDispatchValidation.
int HttpCache::Transaction::DoLoop(int result) {
DCHECK_NE(STATE_UNSET, next_state_);
DCHECK_NE(STATE_NONE, next_state_);
DCHECK(!in_do_loop_);
int rv = result;
State state = next_state_;
do {
state = next_state_;
next_state_ = STATE_UNSET;
base::AutoReset<bool> scoped_in_do_loop(&in_do_loop_, true);
switch (state) {
case STATE_GET_BACKEND:
DCHECK_EQ(OK, rv);
rv = DoGetBackend();
break;
case STATE_GET_BACKEND_COMPLETE:
rv = DoGetBackendComplete(rv);
break;
case STATE_INIT_ENTRY:
DCHECK_EQ(OK, rv);
rv = DoInitEntry();
break;
case STATE_OPEN_ENTRY:
DCHECK_EQ(OK, rv);
rv = DoOpenEntry();
break;
case STATE_OPEN_ENTRY_COMPLETE:
rv = DoOpenEntryComplete(rv);
break;
case STATE_DOOM_ENTRY:
DCHECK_EQ(OK, rv);
rv = DoDoomEntry();
break;
case STATE_DOOM_ENTRY_COMPLETE:
rv = DoDoomEntryComplete(rv);
break;
case STATE_CREATE_ENTRY:
DCHECK_EQ(OK, rv);
rv = DoCreateEntry();
break;
case STATE_CREATE_ENTRY_COMPLETE:
rv = DoCreateEntryComplete(rv);
break;
case STATE_ADD_TO_ENTRY:
DCHECK_EQ(OK, rv);
rv = DoAddToEntry();
break;
case STATE_ADD_TO_ENTRY_COMPLETE:
rv = DoAddToEntryComplete(rv);
break;
case STATE_DONE_HEADERS_ADD_TO_ENTRY_COMPLETE:
rv = DoDoneHeadersAddToEntryComplete(rv);
break;
case STATE_CACHE_READ_RESPONSE:
DCHECK_EQ(OK, rv);
rv = DoCacheReadResponse();
break;
case STATE_CACHE_READ_RESPONSE_COMPLETE:
rv = DoCacheReadResponseComplete(rv);
break;
case STATE_TOGGLE_UNUSED_SINCE_PREFETCH:
DCHECK_EQ(OK, rv);
rv = DoCacheToggleUnusedSincePrefetch();
break;
case STATE_TOGGLE_UNUSED_SINCE_PREFETCH_COMPLETE:
rv = DoCacheToggleUnusedSincePrefetchComplete(rv);
break;
case STATE_CACHE_DISPATCH_VALIDATION:
DCHECK_EQ(OK, rv);
rv = DoCacheDispatchValidation();
break;
case STATE_CACHE_QUERY_DATA:
DCHECK_EQ(OK, rv);
rv = DoCacheQueryData();
break;
case STATE_CACHE_QUERY_DATA_COMPLETE:
rv = DoCacheQueryDataComplete(rv);
break;
case STATE_START_PARTIAL_CACHE_VALIDATION:
DCHECK_EQ(OK, rv);
rv = DoStartPartialCacheValidation();
break;
case STATE_COMPLETE_PARTIAL_CACHE_VALIDATION:
rv = DoCompletePartialCacheValidation(rv);
break;
case STATE_CACHE_UPDATE_STALE_WHILE_REVALIDATE_TIMEOUT:
DCHECK_EQ(OK, rv);
rv = DoCacheUpdateStaleWhileRevalidateTimeout();
break;
case STATE_CACHE_UPDATE_STALE_WHILE_REVALIDATE_TIMEOUT_COMPLETE:
rv = DoCacheUpdateStaleWhileRevalidateTimeoutComplete(rv);
break;
case STATE_SETUP_ENTRY_FOR_READ:
DCHECK_EQ(OK, rv);
rv = DoSetupEntryForRead();
break;
case STATE_SEND_REQUEST:
DCHECK_EQ(OK, rv);
rv = DoSendRequest();
break;
case STATE_SEND_REQUEST_COMPLETE:
rv = DoSendRequestComplete(rv);
break;
case STATE_SUCCESSFUL_SEND_REQUEST:
DCHECK_EQ(OK, rv);
rv = DoSuccessfulSendRequest();
break;
case STATE_UPDATE_CACHED_RESPONSE:
DCHECK_EQ(OK, rv);
rv = DoUpdateCachedResponse();
break;
case STATE_CACHE_WRITE_UPDATED_RESPONSE:
DCHECK_EQ(OK, rv);
rv = DoCacheWriteUpdatedResponse();
break;
case STATE_CACHE_WRITE_UPDATED_RESPONSE_COMPLETE:
rv = DoCacheWriteUpdatedResponseComplete(rv);
break;
case STATE_UPDATE_CACHED_RESPONSE_COMPLETE:
rv = DoUpdateCachedResponseComplete(rv);
break;
case STATE_OVERWRITE_CACHED_RESPONSE:
DCHECK_EQ(OK, rv);
rv = DoOverwriteCachedResponse();
break;
case STATE_CACHE_WRITE_RESPONSE:
DCHECK_EQ(OK, rv);
rv = DoCacheWriteResponse();
break;
case STATE_CACHE_WRITE_RESPONSE_COMPLETE:
rv = DoCacheWriteResponseComplete(rv);
break;
case STATE_TRUNCATE_CACHED_DATA:
DCHECK_EQ(OK, rv);
rv = DoTruncateCachedData();
break;
case STATE_TRUNCATE_CACHED_DATA_COMPLETE:
rv = DoTruncateCachedDataComplete(rv);
break;
case STATE_TRUNCATE_CACHED_METADATA:
DCHECK_EQ(OK, rv);
rv = DoTruncateCachedMetadata();
break;
case STATE_TRUNCATE_CACHED_METADATA_COMPLETE:
rv = DoTruncateCachedMetadataComplete(rv);
break;
case STATE_PARTIAL_HEADERS_RECEIVED:
DCHECK_EQ(OK, rv);
rv = DoPartialHeadersReceived();
break;
case STATE_CACHE_READ_METADATA:
DCHECK_EQ(OK, rv);
rv = DoCacheReadMetadata();
break;
case STATE_CACHE_READ_METADATA_COMPLETE:
rv = DoCacheReadMetadataComplete(rv);
break;
case STATE_HEADERS_PHASE_CANNOT_PROCEED:
rv = DoHeadersPhaseCannotProceed(rv);
break;
case STATE_FINISH_HEADERS:
rv = DoFinishHeaders(rv);
break;
case STATE_FINISH_HEADERS_COMPLETE:
rv = DoFinishHeadersComplete(rv);
break;
case STATE_NETWORK_READ_CACHE_WRITE:
DCHECK_EQ(OK, rv);
rv = DoNetworkReadCacheWrite();
break;
case STATE_NETWORK_READ_CACHE_WRITE_COMPLETE:
rv = DoNetworkReadCacheWriteComplete(rv);
break;
case STATE_CACHE_READ_DATA:
DCHECK_EQ(OK, rv);
rv = DoCacheReadData();
break;
case STATE_CACHE_READ_DATA_COMPLETE:
rv = DoCacheReadDataComplete(rv);
break;
case STATE_NETWORK_READ:
DCHECK_EQ(OK, rv);
rv = DoNetworkRead();
break;
case STATE_NETWORK_READ_COMPLETE:
rv = DoNetworkReadComplete(rv);
break;
default:
NOTREACHED() << "bad state " << state;
rv = ERR_FAILED;
break;
}
DCHECK(next_state_ != STATE_UNSET) << "Previous state was " << state;
} while (rv != ERR_IO_PENDING && next_state_ != STATE_NONE);
// Assert Start() state machine's allowed last state in successful cases when
// caching is happening.
DCHECK(reading_ || rv != OK || !entry_ ||
state == STATE_FINISH_HEADERS_COMPLETE);
if (rv != ERR_IO_PENDING && !callback_.is_null()) {
read_buf_ = nullptr; // Release the buffer before invoking the callback.
base::ResetAndReturn(&callback_).Run(rv);
}
return rv;
}
int HttpCache::Transaction::DoGetBackend() {
cache_pending_ = true;
TransitionToState(STATE_GET_BACKEND_COMPLETE);
net_log_.BeginEvent(NetLogEventType::HTTP_CACHE_GET_BACKEND);
return cache_->GetBackendForTransaction(this);
}
int HttpCache::Transaction::DoGetBackendComplete(int result) {
DCHECK(result == OK || result == ERR_FAILED);
net_log_.EndEventWithNetErrorCode(NetLogEventType::HTTP_CACHE_GET_BACKEND,
result);
cache_pending_ = false;
// Reset mode_ that might get set in this function. This is done because this
// function can be invoked multiple times for a transaction.
mode_ = NONE;
if (!ShouldPassThrough()) {
cache_key_ = cache_->GenerateCacheKey(request_);
// Requested cache access mode.
if (effective_load_flags_ & LOAD_ONLY_FROM_CACHE) {
if (effective_load_flags_ & LOAD_BYPASS_CACHE) {
// The client has asked for nonsense.
TransitionToState(STATE_FINISH_HEADERS);
return ERR_CACHE_MISS;
}
mode_ = READ;
} else if (effective_load_flags_ & LOAD_BYPASS_CACHE) {
mode_ = WRITE;
} else {
mode_ = READ_WRITE;
}
// Downgrade to UPDATE if the request has been externally conditionalized.
if (external_validation_.initialized) {
if (mode_ & WRITE) {
// Strip off the READ_DATA bit (and maybe add back a READ_META bit
// in case READ was off).
mode_ = UPDATE;
} else {
mode_ = NONE;
}
}
}
// Use PUT and DELETE only to invalidate existing stored entries.
if ((method_ == "PUT" || method_ == "DELETE") && mode_ != READ_WRITE &&
mode_ != WRITE) {
mode_ = NONE;
}
// Note that if mode_ == UPDATE (which is tied to external_validation_), the
// transaction behaves the same for GET and HEAD requests at this point: if it
// was not modified, the entry is updated and a response is not returned from
// the cache. If we receive 200, it doesn't matter if there was a validation
// header or not.
if (method_ == "HEAD" && mode_ == WRITE)
mode_ = NONE;
// If must use cache, then we must fail. This can happen for back/forward
// navigations to a page generated via a form post.
if (!(mode_ & READ) && effective_load_flags_ & LOAD_ONLY_FROM_CACHE) {
TransitionToState(STATE_FINISH_HEADERS);
return ERR_CACHE_MISS;
}
if (mode_ == NONE) {
if (partial_) {
partial_->RestoreHeaders(&custom_request_->extra_headers);
partial_.reset();
}
TransitionToState(STATE_SEND_REQUEST);
} else {
TransitionToState(STATE_INIT_ENTRY);
}
// This is only set if we have something to do with the response.
range_requested_ = (partial_.get() != NULL);
return OK;
}
int HttpCache::Transaction::DoInitEntry() {
TRACE_EVENT0("io", "HttpCacheTransaction::DoInitEntry");
DCHECK(!new_entry_);
if (!cache_.get()) {
TransitionToState(STATE_FINISH_HEADERS);
return ERR_UNEXPECTED;
}
if (mode_ == WRITE) {
TransitionToState(STATE_DOOM_ENTRY);
return OK;
}
TransitionToState(STATE_OPEN_ENTRY);
return OK;
}
int HttpCache::Transaction::DoOpenEntry() {
TRACE_EVENT0("io", "HttpCacheTransaction::DoOpenEntry");
DCHECK(!new_entry_);
TransitionToState(STATE_OPEN_ENTRY_COMPLETE);
cache_pending_ = true;
net_log_.BeginEvent(NetLogEventType::HTTP_CACHE_OPEN_ENTRY);
first_cache_access_since_ = TimeTicks::Now();
// See if we already have something working with this cache key.
new_entry_ = cache_->FindActiveEntry(cache_key_);
if (new_entry_)
return OK;
// See if we could potentially quick-reject the entry based on hints the
// backend keeps in memory.
uint8_t in_memory_info =
cache_->GetCurrentBackend()->GetEntryInMemoryData(cache_key_);
if (MaybeRejectBasedOnEntryInMemoryData(in_memory_info)) {
cache_->GetCurrentBackend()->DoomEntry(cache_key_, priority_,
base::DoNothing());
return net::ERR_CACHE_ENTRY_NOT_SUITABLE;
}
return cache_->OpenEntry(cache_key_, &new_entry_, this);
}
int HttpCache::Transaction::DoOpenEntryComplete(int result) {
TRACE_EVENT0("io", "HttpCacheTransaction::DoOpenEntryComplete");
// It is important that we go to STATE_ADD_TO_ENTRY whenever the result is
// OK, otherwise the cache will end up with an active entry without any
// transaction attached.
net_log_.EndEventWithNetErrorCode(NetLogEventType::HTTP_CACHE_OPEN_ENTRY,
result);
cache_pending_ = false;
if (result == OK) {
TransitionToState(STATE_ADD_TO_ENTRY);
return OK;
}
if (result == ERR_CACHE_RACE) {
TransitionToState(STATE_HEADERS_PHASE_CANNOT_PROCEED);
return OK;
}
if (result == ERR_CACHE_ENTRY_NOT_SUITABLE) {
// Documents the case this applies in
DCHECK_EQ(mode_, READ_WRITE);
// Record this as CantConditionalize, but otherwise proceed as we would
// below --- as OpenEntry has already dropped the old entry for us.
couldnt_conditionalize_request_ = true;
validation_cause_ = VALIDATION_CAUSE_ZERO_FRESHNESS;
cant_conditionalize_zero_freshness_from_memhint_ = true;
UpdateCacheEntryStatus(CacheEntryStatus::ENTRY_CANT_CONDITIONALIZE);
}
if (method_ == "PUT" || method_ == "DELETE" ||
(method_ == "HEAD" && mode_ == READ_WRITE)) {
DCHECK(mode_ == READ_WRITE || mode_ == WRITE || method_ == "HEAD");
mode_ = NONE;
TransitionToState(STATE_SEND_REQUEST);
return OK;
}
if (mode_ == READ_WRITE) {
mode_ = WRITE;
TransitionToState(STATE_CREATE_ENTRY);
return OK;
}
if (mode_ == UPDATE) {
// There is no cache entry to update; proceed without caching.
mode_ = NONE;
TransitionToState(STATE_SEND_REQUEST);
return OK;
}
// The entry does not exist, and we are not permitted to create a new entry,
// so we must fail.
TransitionToState(STATE_FINISH_HEADERS);
return ERR_CACHE_MISS;
}
int HttpCache::Transaction::DoDoomEntry() {
TRACE_EVENT0("io", "HttpCacheTransaction::DoDoomEntry");
TransitionToState(STATE_DOOM_ENTRY_COMPLETE);
cache_pending_ = true;
if (first_cache_access_since_.is_null())
first_cache_access_since_ = TimeTicks::Now();
net_log_.BeginEvent(NetLogEventType::HTTP_CACHE_DOOM_ENTRY);
return cache_->DoomEntry(cache_key_, this);
}
int HttpCache::Transaction::DoDoomEntryComplete(int result) {
TRACE_EVENT0("io", "HttpCacheTransaction::DoDoomEntryComplete");
net_log_.EndEventWithNetErrorCode(NetLogEventType::HTTP_CACHE_DOOM_ENTRY,
result);
cache_pending_ = false;
TransitionToState(result == ERR_CACHE_RACE
? STATE_HEADERS_PHASE_CANNOT_PROCEED
: STATE_CREATE_ENTRY);
return OK;
}
int HttpCache::Transaction::DoCreateEntry() {
TRACE_EVENT0("io", "HttpCacheTransaction::DoCreateEntry");
DCHECK(!new_entry_);
TransitionToState(STATE_CREATE_ENTRY_COMPLETE);
cache_pending_ = true;
net_log_.BeginEvent(NetLogEventType::HTTP_CACHE_CREATE_ENTRY);
return cache_->CreateEntry(cache_key_, &new_entry_, this);
}
int HttpCache::Transaction::DoCreateEntryComplete(int result) {
TRACE_EVENT0("io", "HttpCacheTransaction::DoCreateEntryComplete");
// It is important that we go to STATE_ADD_TO_ENTRY whenever the result is
// OK, otherwise the cache will end up with an active entry without any
// transaction attached.
net_log_.EndEventWithNetErrorCode(NetLogEventType::HTTP_CACHE_CREATE_ENTRY,
result);
cache_pending_ = false;
switch (result) {
case OK:
TransitionToState(STATE_ADD_TO_ENTRY);
break;
case ERR_CACHE_RACE:
TransitionToState(STATE_HEADERS_PHASE_CANNOT_PROCEED);
break;
default:
// We have a race here: Maybe we failed to open the entry and decided to
// create one, but by the time we called create, another transaction
// already created the entry. If we want to eliminate this issue, we
// need an atomic OpenOrCreate() method exposed by the disk cache.
DLOG(WARNING) << "Unable to create cache entry";
// Set the mode to NONE in order to bypass the cache entry and read from
// the network directly.
mode_ = NONE;
if (!done_headers_create_new_entry_) {
if (partial_)
partial_->RestoreHeaders(&custom_request_->extra_headers);
TransitionToState(STATE_SEND_REQUEST);
return OK;
}
// The headers have already been received as a result of validation,
// triggering the doom of the old entry. So no network request needs to
// be sent. Note that since mode_ is NONE, the response won't be written
// to cache. Transition to STATE_CACHE_WRITE_RESPONSE as that's the state
// the transaction left off on when it tried to create the new entry.
done_headers_create_new_entry_ = false;
TransitionToState(STATE_CACHE_WRITE_RESPONSE);
}
return OK;
}
int HttpCache::Transaction::DoAddToEntry() {
TRACE_EVENT0("io", "HttpCacheTransaction::DoAddToEntry");
DCHECK(new_entry_);
cache_pending_ = true;
net_log_.BeginEvent(NetLogEventType::HTTP_CACHE_ADD_TO_ENTRY);
DCHECK(entry_lock_waiting_since_.is_null());
int rv = cache_->AddTransactionToEntry(new_entry_, this);
DCHECK_EQ(rv, ERR_IO_PENDING);
// If headers phase is already done then we are here because of validation not
// matching and creating a new entry. This transaction should be the
// first transaction of that new entry and thus it will not have cache lock
// delays, thus returning early from here.
if (done_headers_create_new_entry_) {
DCHECK_EQ(mode_, WRITE);
TransitionToState(STATE_DONE_HEADERS_ADD_TO_ENTRY_COMPLETE);
return rv;
}
TransitionToState(STATE_ADD_TO_ENTRY_COMPLETE);
entry_lock_waiting_since_ = TimeTicks::Now();
AddCacheLockTimeoutHandler(new_entry_);
return rv;
}
void HttpCache::Transaction::AddCacheLockTimeoutHandler(ActiveEntry* entry) {
DCHECK(next_state_ == STATE_ADD_TO_ENTRY_COMPLETE ||
next_state_ == STATE_FINISH_HEADERS_COMPLETE);
if ((bypass_lock_for_test_ && next_state_ == STATE_ADD_TO_ENTRY_COMPLETE) ||
(bypass_lock_after_headers_for_test_ &&
next_state_ == STATE_FINISH_HEADERS_COMPLETE)) {
base::ThreadTaskRunnerHandle::Get()->PostTask(
FROM_HERE,
base::Bind(&HttpCache::Transaction::OnCacheLockTimeout,
weak_factory_.GetWeakPtr(), entry_lock_waiting_since_));
} else {
int timeout_milliseconds = 20 * 1000;
if (partial_ && entry->writers && !entry->writers->IsEmpty() &&
entry->writers->IsExclusive()) {
// Even though entry_->writers takes care of allowing multiple writers to
// simultaneously govern reading from the network and writing to the cache
// for full requests, partial requests are still blocked by the
// reader/writer lock.
// Bypassing the cache after 25 ms of waiting for the cache lock
// eliminates a long running issue, http://crbug.com/31014, where
// two of the same media resources could not be played back simultaneously
// due to one locking the cache entry until the entire video was
// downloaded.
// Bypassing the cache is not ideal, as we are now ignoring the cache
// entirely for all range requests to a resource beyond the first. This
// is however a much more succinct solution than the alternatives, which
// would require somewhat significant changes to the http caching logic.
//
// Allow some timeout slack for the entry addition to complete in case
// the writer lock is imminently released; we want to avoid skipping
// the cache if at all possible. See http://crbug.com/408765
timeout_milliseconds = 25;
}
base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
FROM_HERE,
base::Bind(&HttpCache::Transaction::OnCacheLockTimeout,
weak_factory_.GetWeakPtr(), entry_lock_waiting_since_),
TimeDelta::FromMilliseconds(timeout_milliseconds));
}
}
int HttpCache::Transaction::DoAddToEntryComplete(int result) {
TRACE_EVENT0("io", "HttpCacheTransaction::DoAddToEntryComplete");
net_log_.EndEventWithNetErrorCode(NetLogEventType::HTTP_CACHE_ADD_TO_ENTRY,
result);
const TimeDelta entry_lock_wait =
TimeTicks::Now() - entry_lock_waiting_since_;
UMA_HISTOGRAM_TIMES("HttpCache.EntryLockWait", entry_lock_wait);
entry_lock_waiting_since_ = TimeTicks();
DCHECK(new_entry_);
cache_pending_ = false;
if (result == OK)
entry_ = new_entry_;
// If there is a failure, the cache should have taken care of new_entry_.
new_entry_ = NULL;
if (result == ERR_CACHE_RACE) {
TransitionToState(STATE_HEADERS_PHASE_CANNOT_PROCEED);
return OK;
}
if (result == ERR_CACHE_LOCK_TIMEOUT) {
if (mode_ == READ) {
TransitionToState(STATE_FINISH_HEADERS);
return ERR_CACHE_MISS;
}
// The cache is busy, bypass it for this transaction.
mode_ = NONE;
TransitionToState(STATE_SEND_REQUEST);
if (partial_) {
partial_->RestoreHeaders(&custom_request_->extra_headers);
partial_.reset();
}
return OK;
}
// TODO(crbug.com/713354) Access timestamp for histograms only if entry is
// already written, to avoid data race since cache thread can also access
// this.
if (!cache_->IsWritingInProgress(entry_))
open_entry_last_used_ = entry_->disk_entry->GetLastUsed();
// TODO(jkarlin): We should either handle the case or DCHECK.
if (result != OK) {
NOTREACHED();
TransitionToState(STATE_FINISH_HEADERS);
return result;
}
if (mode_ == WRITE) {
if (partial_)
partial_->RestoreHeaders(&custom_request_->extra_headers);
TransitionToState(STATE_SEND_REQUEST);
} else {
// We have to read the headers from the cached entry.
DCHECK(mode_ & READ_META);
TransitionToState(STATE_CACHE_READ_RESPONSE);
}
return OK;
}
int HttpCache::Transaction::DoDoneHeadersAddToEntryComplete(int result) {
// This transaction's response headers did not match its ActiveEntry so it
// created a new ActiveEntry (new_entry_) to write to (and doomed the old
// one). Now that the new entry has been created, start writing the response.
DCHECK_EQ(result, OK);
DCHECK_EQ(mode_, WRITE);
DCHECK(new_entry_);
DCHECK(response_.headers);
cache_pending_ = false;
entry_ = new_entry_;
done_headers_create_new_entry_ = false;
DCHECK_NE(response_.headers->response_code(), 304);
DCHECK(cache_->CanTransactionWriteResponseHeaders(
entry_, this, partial_ != nullptr, false));
TransitionToState(STATE_CACHE_WRITE_RESPONSE);
return OK;
}
int HttpCache::Transaction::DoCacheReadResponse() {
TRACE_EVENT0("io", "HttpCacheTransaction::DoCacheReadResponse");
DCHECK(entry_);
TransitionToState(STATE_CACHE_READ_RESPONSE_COMPLETE);
io_buf_len_ = entry_->disk_entry->GetDataSize(kResponseInfoIndex);
read_buf_ = base::MakeRefCounted<IOBuffer>(io_buf_len_);
net_log_.BeginEvent(NetLogEventType::HTTP_CACHE_READ_INFO);
return entry_->disk_entry->ReadData(kResponseInfoIndex, 0, read_buf_.get(),
io_buf_len_, io_callback_);
}
int HttpCache::Transaction::DoCacheReadResponseComplete(int result) {
TRACE_EVENT0("io", "HttpCacheTransaction::DoCacheReadResponseComplete");
net_log_.EndEventWithNetErrorCode(NetLogEventType::HTTP_CACHE_READ_INFO,
result);
// Record the time immediately before the cached response is parsed.
read_headers_since_ = TimeTicks::Now();
if (result != io_buf_len_ ||
!HttpCache::ParseResponseInfo(read_buf_->data(), io_buf_len_, &response_,
&truncated_)) {
return OnCacheReadError(result, true);
}
// TODO(crbug.com/713354) Only get data size if there is no other transaction
// currently writing the response body due to the data race mentioned in the
// associated bug.
if (!cache_->IsWritingInProgress(entry_)) {
int current_size = entry_->disk_entry->GetDataSize(kResponseContentIndex);
int64_t full_response_length = response_.headers->GetContentLength();
// Some resources may have slipped in as truncated when they're not.
if (full_response_length == current_size)
truncated_ = false;
// The state machine's handling of StopCaching unfortunately doesn't deal
// well with resources that are larger than 2GB when there is a truncated or
// sparse cache entry. While the state machine is reworked to resolve this,
// the following logic is put in place to defer such requests to the
// network. The cache should not be storing multi gigabyte resources. See
// http://crbug.com/89567.
if ((truncated_ || response_.headers->response_code() == 206) &&
!range_requested_ &&
full_response_length > std::numeric_limits<int32_t>::max()) {
DCHECK(!partial_);
// Doom the entry so that no other transaction gets added to this entry
// and avoid a race of not being able to check this condition because
// writing is in progress.
DoneWithEntry(false);
TransitionToState(STATE_SEND_REQUEST);
return OK;
}
}
if (response_.unused_since_prefetch !=
!!(request_->load_flags & LOAD_PREFETCH)) {
// Either this is the first use of an entry since it was prefetched XOR
// this is a prefetch. The value of response.unused_since_prefetch is
// valid for this transaction but the bit needs to be flipped in storage.
TransitionToState(STATE_TOGGLE_UNUSED_SINCE_PREFETCH);
return OK;
}
TransitionToState(STATE_CACHE_DISPATCH_VALIDATION);
return OK;
}
int HttpCache::Transaction::DoCacheToggleUnusedSincePrefetch() {
TRACE_EVENT0("io", "HttpCacheTransaction::DoCacheToggleUnusedSincePrefetch");
// Write back the toggled value for the next use of this entry.
response_.unused_since_prefetch = !response_.unused_since_prefetch;
// TODO(jkarlin): If DoUpdateCachedResponse is also called for this
// transaction then metadata will be written to cache twice. If prefetching
// becomes more common, consider combining the writes.
TransitionToState(STATE_TOGGLE_UNUSED_SINCE_PREFETCH_COMPLETE);
return WriteResponseInfoToEntry(false);
}
int HttpCache::Transaction::DoCacheToggleUnusedSincePrefetchComplete(
int result) {
TRACE_EVENT0(
NetTracingCategory(),
"HttpCacheTransaction::DoCacheToggleUnusedSincePrefetchComplete");
// Restore the original value for this transaction.
response_.unused_since_prefetch = !response_.unused_since_prefetch;
TransitionToState(STATE_CACHE_DISPATCH_VALIDATION);
return OnWriteResponseInfoToEntryComplete(result);
}
int HttpCache::Transaction::DoCacheDispatchValidation() {
TRACE_EVENT0("io", "HttpCacheTransaction::DoCacheDispatchValidation");
// We now have access to the cache entry.
//
// o if we are a reader for the transaction, then we can start reading the
// cache entry.
//
// o if we can read or write, then we should check if the cache entry needs
// to be validated and then issue a network request if needed or just read
// from the cache if the cache entry is already valid.
//
// o if we are set to UPDATE, then we are handling an externally
// conditionalized request (if-modified-since / if-none-match). We check
// if the request headers define a validation request.
//
int result = ERR_FAILED;
switch (mode_) {
case READ:
UpdateCacheEntryStatus(CacheEntryStatus::ENTRY_USED);
result = BeginCacheRead();
break;
case READ_WRITE:
result = BeginPartialCacheValidation();
break;
case UPDATE:
result = BeginExternallyConditionalizedRequest();
break;
case WRITE:
default:
NOTREACHED();
}
return result;
}
int HttpCache::Transaction::DoCacheQueryData() {
TransitionToState(STATE_CACHE_QUERY_DATA_COMPLETE);
return entry_->disk_entry->ReadyForSparseIO(io_callback_);
}
int HttpCache::Transaction::DoCacheQueryDataComplete(int result) {
DCHECK_EQ(OK, result);
if (!cache_.get()) {
TransitionToState(STATE_FINISH_HEADERS);
return ERR_UNEXPECTED;
}
return ValidateEntryHeadersAndContinue();
}
// We may end up here multiple times for a given request.
int HttpCache::Transaction::DoStartPartialCacheValidation() {
if (mode_ == NONE) {
TransitionToState(STATE_FINISH_HEADERS);
return OK;
}
TransitionToState(STATE_COMPLETE_PARTIAL_CACHE_VALIDATION);
return partial_->ShouldValidateCache(entry_->disk_entry, io_callback_);
}
int HttpCache::Transaction::DoCompletePartialCacheValidation(int result) {
if (!result) {
// This is the end of the request.
DoneWithEntry(true);
TransitionToState(STATE_FINISH_HEADERS);
return result;
}
if (result < 0) {
TransitionToState(STATE_FINISH_HEADERS);
return result;
}
partial_->PrepareCacheValidation(entry_->disk_entry,
&custom_request_->extra_headers);
if (reading_ && partial_->IsCurrentRangeCached()) {
TransitionToState(STATE_CACHE_READ_DATA);
return OK;
}
return BeginCacheValidation();
}
int HttpCache::Transaction::DoCacheUpdateStaleWhileRevalidateTimeout() {
TRACE_EVENT0(
"io", "HttpCacheTransaction::DoCacheUpdateStaleWhileRevalidateTimeout");
response_.stale_revalidate_timeout =
cache_->clock_->Now() + kStaleRevalidateTimeout;
TransitionToState(STATE_CACHE_UPDATE_STALE_WHILE_REVALIDATE_TIMEOUT_COMPLETE);
return WriteResponseInfoToEntry(false);
}
int HttpCache::Transaction::DoCacheUpdateStaleWhileRevalidateTimeoutComplete(
int result) {
TRACE_EVENT0(
"io",
"HttpCacheTransaction::DoCacheUpdateStaleWhileRevalidateTimeoutComplete");
TransitionToState(STATE_SETUP_ENTRY_FOR_READ);
return OnWriteResponseInfoToEntryComplete(result);
}
int HttpCache::Transaction::DoSendRequest() {
TRACE_EVENT0("io", "HttpCacheTransaction::DoSendRequest");
DCHECK(mode_ & WRITE || mode_ == NONE);
DCHECK(!network_trans_.get());
send_request_since_ = TimeTicks::Now();
// Create a network transaction.
int rv =
cache_->network_layer_->CreateTransaction(priority_, &network_trans_);
if (rv != OK) {
TransitionToState(STATE_FINISH_HEADERS);
return rv;
}
network_trans_->SetBeforeNetworkStartCallback(before_network_start_callback_);
network_trans_->SetBeforeHeadersSentCallback(before_headers_sent_callback_);
network_trans_->SetRequestHeadersCallback(request_headers_callback_);
network_trans_->SetResponseHeadersCallback(response_headers_callback_);
// Old load timing information, if any, is now obsolete.
network_transaction_info_.old_network_trans_load_timing.reset();
network_transaction_info_.old_remote_endpoint = IPEndPoint();
if (websocket_handshake_stream_base_create_helper_)
network_trans_->SetWebSocketHandshakeStreamCreateHelper(
websocket_handshake_stream_base_create_helper_);
TransitionToState(STATE_SEND_REQUEST_COMPLETE);
rv = network_trans_->Start(request_, io_callback_, net_log_);
return rv;
}
int HttpCache::Transaction::DoSendRequestComplete(int result) {
TRACE_EVENT0("io", "HttpCacheTransaction::DoSendRequestComplete");
if (!cache_.get()) {
TransitionToState(STATE_FINISH_HEADERS);
return ERR_UNEXPECTED;
}
// If we tried to conditionalize the request and failed, we know
// we won't be reading from the cache after this point.
if (couldnt_conditionalize_request_)
mode_ = WRITE;
if (result == OK) {
TransitionToState(STATE_SUCCESSFUL_SEND_REQUEST);
return OK;
}
const HttpResponseInfo* response = network_trans_->GetResponseInfo();
response_.network_accessed = response->network_accessed;
// Do not record requests that have network errors or restarts.
UpdateCacheEntryStatus(CacheEntryStatus::ENTRY_OTHER);
if (IsCertificateError(result)) {
// If we get a certificate error, then there is a certificate in ssl_info,
// so GetResponseInfo() should never return NULL here.
DCHECK(response);
response_.ssl_info = response->ssl_info;
} else if (result == ERR_SSL_CLIENT_AUTH_CERT_NEEDED) {
DCHECK(response);
response_.cert_request_info = response->cert_request_info;
} else if (response_.was_cached) {
DoneWithEntry(true);
}
TransitionToState(STATE_FINISH_HEADERS);
return result;
}
// We received the response headers and there is no error.
int HttpCache::Transaction::DoSuccessfulSendRequest() {
TRACE_EVENT0("io", "HttpCacheTransaction::DoSuccessfulSendRequest");
DCHECK(!new_response_);
const HttpResponseInfo* new_response = network_trans_->GetResponseInfo();
if (new_response->headers->response_code() == 401 ||
new_response->headers->response_code() == 407) {
SetAuthResponse(*new_response);
if (!reading_) {
TransitionToState(STATE_FINISH_HEADERS);
return OK;
}
// We initiated a second request the caller doesn't know about. We should be
// able to authenticate this request because we should have authenticated
// this URL moments ago.
if (IsReadyToRestartForAuth()) {
DCHECK(!response_.auth_challenge.get());
TransitionToState(STATE_SEND_REQUEST_COMPLETE);
// In theory we should check to see if there are new cookies, but there
// is no way to do that from here.
return network_trans_->RestartWithAuth(AuthCredentials(), io_callback_);
}
// We have to perform cleanup at this point so that at least the next
// request can succeed. We do not retry at this point, because data
// has been read and we have no way to gather credentials. We would
// fail again, and potentially loop. This can happen if the credentials
// expire while chrome is suspended.
if (entry_)
DoomPartialEntry(false);
mode_ = NONE;
partial_.reset();
ResetNetworkTransaction();
TransitionToState(STATE_FINISH_HEADERS);
return ERR_CACHE_AUTH_FAILURE_AFTER_READ;
}
new_response_ = new_response;
if (!ValidatePartialResponse() && !auth_response_.headers.get()) {
// Something went wrong with this request and we have to restart it.
// If we have an authentication response, we are exposed to weird things
// hapenning if the user cancels the authentication before we receive
// the new response.
net_log_.AddEvent(NetLogEventType::HTTP_CACHE_RE_SEND_PARTIAL_REQUEST);
UpdateCacheEntryStatus(CacheEntryStatus::ENTRY_OTHER);
SetResponse(HttpResponseInfo());
ResetNetworkTransaction();
new_response_ = NULL;
TransitionToState(STATE_SEND_REQUEST);
return OK;
}
if (handling_206_ && mode_ == READ_WRITE && !truncated_ && !is_sparse_) {
// We have stored the full entry, but it changed and the server is
// sending a range. We have to delete the old entry.
UpdateCacheEntryStatus(CacheEntryStatus::ENTRY_OTHER);
DoneWithEntry(false);
}
if (mode_ == WRITE &&
cache_entry_status_ != CacheEntryStatus::ENTRY_CANT_CONDITIONALIZE) {
UpdateCacheEntryStatus(CacheEntryStatus::ENTRY_NOT_IN_CACHE);
}
// Invalidate any cached GET with a successful PUT or DELETE.
if (mode_ == WRITE && (method_ == "PUT" || method_ == "DELETE")) {
if (NonErrorResponse(new_response->headers->response_code()) &&
(entry_ && !entry_->doomed)) {
int ret = cache_->DoomEntry(cache_key_, NULL);
DCHECK_EQ(OK, ret);
}
// Do not invalidate the entry if its a failed Delete or Put.
DoneWithEntry(true);
}
// Invalidate any cached GET with a successful POST.
if (!(effective_load_flags_ & LOAD_DISABLE_CACHE) && method_ == "POST" &&
NonErrorResponse(new_response->headers->response_code())) {
cache_->DoomMainEntryForUrl(request_->url, request_->top_frame_origin);
}
RecordNoStoreHeaderHistogram(request_->load_flags, new_response);
if (new_response_->headers->response_code() == 416 &&
(method_ == "GET" || method_ == "POST")) {
// If there is an active entry it may be destroyed with this transaction.
SetResponse(*new_response_);
TransitionToState(STATE_FINISH_HEADERS);
return OK;
}
// Are we expecting a response to a conditional query?
if (mode_ == READ_WRITE || mode_ == UPDATE) {
if (new_response->headers->response_code() == 304 || handling_206_) {
UpdateCacheEntryStatus(CacheEntryStatus::ENTRY_VALIDATED);
TransitionToState(STATE_UPDATE_CACHED_RESPONSE);
return OK;
}
UpdateCacheEntryStatus(CacheEntryStatus::ENTRY_UPDATED);
mode_ = WRITE;
}
TransitionToState(STATE_OVERWRITE_CACHED_RESPONSE);
return OK;
}
// We received 304 or 206 and we want to update the cached response headers.
int HttpCache::Transaction::DoUpdateCachedResponse() {
TRACE_EVENT0("io", "HttpCacheTransaction::DoUpdateCachedResponse");
int rv = OK;
// Update the cached response based on the headers and properties of
// new_response_.
response_.headers->Update(*new_response_->headers.get());
response_.stale_revalidate_timeout = base::Time();
response_.response_time = new_response_->response_time;
response_.request_time = new_response_->request_time;
response_.network_accessed = new_response_->network_accessed;
response_.unused_since_prefetch = new_response_->unused_since_prefetch;
response_.ssl_info = new_response_->ssl_info;
if (new_response_->vary_data.is_valid()) {
response_.vary_data = new_response_->vary_data;
} else if (response_.vary_data.is_valid()) {
// There is a vary header in the stored response but not in the current one.
// Update the data with the new request headers.
HttpVaryData new_vary_data;
new_vary_data.Init(*request_, *response_.headers.get());
response_.vary_data = new_vary_data;
}
if (response_.headers->HasHeaderValue("cache-control", "no-store")) {
if (!entry_->doomed) {
int ret = cache_->DoomEntry(cache_key_, NULL);
DCHECK_EQ(OK, ret);
}
TransitionToState(STATE_UPDATE_CACHED_RESPONSE_COMPLETE);
} else {
// If we are already reading, we already updated the headers for this
// request; doing it again will change Content-Length.
if (!reading_) {
TransitionToState(STATE_CACHE_WRITE_UPDATED_RESPONSE);
rv = OK;
} else {
TransitionToState(STATE_UPDATE_CACHED_RESPONSE_COMPLETE);
}
}
return rv;
}
int HttpCache::Transaction::DoCacheWriteUpdatedResponse() {
TRACE_EVENT0("io", "HttpCacheTransaction::DoCacheWriteUpdatedResponse");
TransitionToState(STATE_CACHE_WRITE_UPDATED_RESPONSE_COMPLETE);
return WriteResponseInfoToEntry(false);
}
int HttpCache::Transaction::DoCacheWriteUpdatedResponseComplete(int result) {
TRACE_EVENT0("io",
"HttpCacheTransaction::DoCacheWriteUpdatedResponseComplete");
TransitionToState(STATE_UPDATE_CACHED_RESPONSE_COMPLETE);
return OnWriteResponseInfoToEntryComplete(result);
}
int HttpCache::Transaction::DoUpdateCachedResponseComplete(int result) {
TRACE_EVENT0("io", "HttpCacheTransaction::DoUpdateCachedResponseComplete");
if (mode_ == UPDATE) {
DCHECK(!handling_206_);
// We got a "not modified" response and already updated the corresponding
// cache entry above.
//
// By stopping to write to the cache now, we make sure that the 304 rather
// than the cached 200 response, is what will be returned to the user.
DoneWithEntry(true);
} else if (entry_ && !handling_206_) {
DCHECK_EQ(READ_WRITE, mode_);
if ((!partial_ && !cache_->IsWritingInProgress(entry_)) ||
(partial_ && partial_->IsLastRange())) {
mode_ = READ;
}
// We no longer need the network transaction, so destroy it.
if (network_trans_)
ResetNetworkTransaction();
} else if (entry_ && handling_206_ && truncated_ &&
partial_->initial_validation()) {
// We just finished the validation of a truncated entry, and the server
// is willing to resume the operation. Now we go back and start serving
// the first part to the user.
if (network_trans_)
ResetNetworkTransaction();
new_response_ = NULL;
TransitionToState(STATE_START_PARTIAL_CACHE_VALIDATION);
partial_->SetRangeToStartDownload();
return OK;
}
TransitionToState(STATE_OVERWRITE_CACHED_RESPONSE);
return OK;
}
int HttpCache::Transaction::DoOverwriteCachedResponse() {
TRACE_EVENT0("io", "HttpCacheTransaction::DoOverwriteCachedResponse");
if (mode_ & READ) {
TransitionToState(STATE_PARTIAL_HEADERS_RECEIVED);
return OK;
}
// We change the value of Content-Length for partial content.
if (handling_206_ && partial_)
partial_->FixContentLength(new_response_->headers.get());
SetResponse(*new_response_);
if (method_ == "HEAD") {
// This response is replacing the cached one.
DoneWithEntry(false);
new_response_ = NULL;
TransitionToState(STATE_FINISH_HEADERS);
return OK;
}
if (handling_206_ && !CanResume(false)) {
// There is no point in storing this resource because it will never be used.
// This may change if we support LOAD_ONLY_FROM_CACHE with sparse entries.
DoneWithEntry(false);
if (partial_)
partial_->FixResponseHeaders(response_.headers.get(), true);
TransitionToState(STATE_PARTIAL_HEADERS_RECEIVED);
return OK;
}
TransitionToState(STATE_CACHE_WRITE_RESPONSE);
return OK;
}
int HttpCache::Transaction::DoCacheWriteResponse() {
TRACE_EVENT0("io", "HttpCacheTransaction::DoCacheWriteResponse");
// Invalidate any current entry with a successful response if this transaction
// cannot write to this entry. This transaction then continues to read from
// the network without writing to the backend.
bool is_match = response_.headers->response_code() == 304;
if (entry_ && response_.headers &&
!cache_->CanTransactionWriteResponseHeaders(
entry_, this, partial_ != nullptr, is_match)) {
done_headers_create_new_entry_ = true;
// The transaction needs to overwrite this response. Doom the current entry,
// create a new one (by going to STATE_INIT_ENTRY), and then jump straight
// to writing out the response, bypassing the headers checks. The mode_ is
// set to WRITE in order to doom any other existing entries that might exist
// so that this transaction can go straight to writing a response.
mode_ = WRITE;
TransitionToState(STATE_INIT_ENTRY);
cache_->DoomEntryValidationNoMatch(entry_);
entry_ = nullptr;
return OK;
}
TransitionToState(STATE_CACHE_WRITE_RESPONSE_COMPLETE);
return WriteResponseInfoToEntry(truncated_);
}
int HttpCache::Transaction::DoCacheWriteResponseComplete(int result) {
TRACE_EVENT0("io", "HttpCacheTransaction::DoCacheWriteResponseComplete");
TransitionToState(STATE_TRUNCATE_CACHED_DATA);
return OnWriteResponseInfoToEntryComplete(result);
}
int HttpCache::Transaction::DoTruncateCachedData() {
TRACE_EVENT0("io", "HttpCacheTransaction::DoTruncateCachedData");
TransitionToState(STATE_TRUNCATE_CACHED_DATA_COMPLETE);
if (!entry_)
return OK;
if (net_log_.IsCapturing())
net_log_.BeginEvent(NetLogEventType::HTTP_CACHE_WRITE_DATA);
// Truncate the stream.
return WriteToEntry(kResponseContentIndex, 0, NULL, 0, io_callback_);
}
int HttpCache::Transaction::DoTruncateCachedDataComplete(int result) {
TRACE_EVENT0("io", "HttpCacheTransaction::DoInitEntry");
if (entry_) {
if (net_log_.IsCapturing()) {
net_log_.EndEventWithNetErrorCode(NetLogEventType::HTTP_CACHE_WRITE_DATA,
result);
}
}
TransitionToState(STATE_TRUNCATE_CACHED_METADATA);
return OK;
}
int HttpCache::Transaction::DoTruncateCachedMetadata() {
TRACE_EVENT0("io", "HttpCacheTransaction::DoTruncateCachedMetadata");
TransitionToState(STATE_TRUNCATE_CACHED_METADATA_COMPLETE);
if (!entry_)
return OK;
if (net_log_.IsCapturing())
net_log_.BeginEvent(NetLogEventType::HTTP_CACHE_WRITE_INFO);
return WriteToEntry(kMetadataIndex, 0, NULL, 0, io_callback_);
}
int HttpCache::Transaction::DoTruncateCachedMetadataComplete(int result) {
TRACE_EVENT0("io", "HttpCacheTransaction::DoTruncateCachedMetadataComplete");
if (entry_) {
if (net_log_.IsCapturing()) {
net_log_.EndEventWithNetErrorCode(NetLogEventType::HTTP_CACHE_WRITE_INFO,
result);
}
}
TransitionToState(STATE_PARTIAL_HEADERS_RECEIVED);
return OK;
}
int HttpCache::Transaction::DoPartialHeadersReceived() {
new_response_ = NULL;
if (!partial_) {
if (entry_ && entry_->disk_entry->GetDataSize(kMetadataIndex) &&
!base::FeatureList::IsEnabled(net::features::kIsolatedCodeCache)) {
TransitionToState(STATE_CACHE_READ_METADATA);
} else {
TransitionToState(STATE_FINISH_HEADERS);
}
return OK;
}
if (mode_ != NONE && !reading_) {
// We are about to return the headers for a byte-range request to the user,
// so let's fix them.
partial_->FixResponseHeaders(response_.headers.get(), true);
}
TransitionToState(STATE_FINISH_HEADERS);
return OK;
}
int HttpCache::Transaction::DoHeadersPhaseCannotProceed(int result) {
// If its the Start state machine and it cannot proceed due to a cache
// failure, restart this transaction.
DCHECK(!reading_);
// Reset before invoking SetRequest() which can reset the request info sent to
// network transaction.
if (network_trans_)
network_trans_.reset();
new_response_ = nullptr;
SetRequest(net_log_);
entry_ = nullptr;
// Bypass the cache for timeout scenario.
if (result == ERR_CACHE_LOCK_TIMEOUT)
effective_load_flags_ |= LOAD_DISABLE_CACHE;
TransitionToState(STATE_GET_BACKEND);
return OK;
}
int HttpCache::Transaction::DoFinishHeaders(int result) {
if (!cache_.get() || !entry_ || result != OK) {
TransitionToState(STATE_NONE);
return result;
}
TransitionToState(STATE_FINISH_HEADERS_COMPLETE);
// If it was an auth failure, this transaction should continue to be
// headers_transaction till consumer takes an action, so no need to do
// anything now.
// TODO(crbug.com/740947). See the issue for a suggestion for cleaning the
// state machine to be able to remove this condition.
if (auth_response_.headers.get())
return OK;
// If the transaction needs to wait because another transaction is still
// writing the response body, it will return ERR_IO_PENDING now and the
// io_callback_ will be invoked when the wait is done.
int rv = cache_->DoneWithResponseHeaders(entry_, this, partial_ != nullptr);
DCHECK(!reading_ || rv == OK) << "Expected OK, but got " << rv;
if (rv == ERR_IO_PENDING) {
DCHECK(entry_lock_waiting_since_.is_null());
entry_lock_waiting_since_ = TimeTicks::Now();
AddCacheLockTimeoutHandler(entry_);
}
return rv;
}
int HttpCache::Transaction::DoFinishHeadersComplete(int rv) {
entry_lock_waiting_since_ = TimeTicks();
if (rv == ERR_CACHE_RACE || rv == ERR_CACHE_LOCK_TIMEOUT) {
TransitionToState(STATE_HEADERS_PHASE_CANNOT_PROCEED);
return rv;
}
if (network_trans_ && InWriters()) {
entry_->writers->SetNetworkTransaction(this, std::move(network_trans_));
moved_network_transaction_to_writers_ = true;
}
// If already reading, that means it is a partial request coming back to the
// headers phase, continue to the appropriate reading state.
if (reading_) {
int rv = TransitionToReadingState();
DCHECK_EQ(OK, rv);
return OK;
}
TransitionToState(STATE_NONE);
return rv;
}
int HttpCache::Transaction::DoCacheReadMetadata() {
TRACE_EVENT0("io", "HttpCacheTransaction::DoCacheReadMetadata");
DCHECK(entry_);
DCHECK(!response_.metadata.get());
DCHECK(!base::FeatureList::IsEnabled(net::features::kIsolatedCodeCache));
TransitionToState(STATE_CACHE_READ_METADATA_COMPLETE);
response_.metadata = base::MakeRefCounted<IOBufferWithSize>(
entry_->disk_entry->GetDataSize(kMetadataIndex));
net_log_.BeginEvent(NetLogEventType::HTTP_CACHE_READ_INFO);
return entry_->disk_entry->ReadData(kMetadataIndex, 0,
response_.metadata.get(),
response_.metadata->size(),
io_callback_);
}
int HttpCache::Transaction::DoCacheReadMetadataComplete(int result) {
TRACE_EVENT0("io", "HttpCacheTransaction::DoCacheReadMetadataComplete");
net_log_.EndEventWithNetErrorCode(NetLogEventType::HTTP_CACHE_READ_INFO,
result);
if (result != response_.metadata->size())
return OnCacheReadError(result, false);
TransitionToState(STATE_FINISH_HEADERS);
return OK;
}
int HttpCache::Transaction::DoNetworkReadCacheWrite() {
TRACE_EVENT0("io", "HttpCacheTransaction::DoNetworkReadCacheWrite");
DCHECK(InWriters());
TransitionToState(STATE_NETWORK_READ_CACHE_WRITE_COMPLETE);
return entry_->writers->Read(read_buf_, io_buf_len_, io_callback_, this);
}
int HttpCache::Transaction::DoNetworkReadCacheWriteComplete(int result) {
TRACE_EVENT0("io", "HttpCacheTransaction::DoNetworkReadCacheWriteComplete");
if (!cache_.get()) {
TransitionToState(STATE_NONE);
return ERR_UNEXPECTED;
}
// |result| will be error code in case of network read failure and |this|
// cannot proceed further, so set entry_ to null. |result| will not be error
// in case of cache write failure since |this| can continue to read from the
// network. If response is completed, then also set entry to null.
if (result < 0) {
// We should have discovered this error in WriterAboutToBeRemovedFromEntry
DCHECK_EQ(result, shared_writing_error_);
DCHECK_EQ(NONE, mode_);
DCHECK(!entry_);
TransitionToState(STATE_NONE);
return result;
}
if (partial_) {
return DoPartialNetworkReadCompleted(result);
}
if (result == 0) {
DCHECK_EQ(NONE, mode_);
DCHECK(!entry_);
} else {
read_offset_ += result;
}
TransitionToState(STATE_NONE);
return result;
}
int HttpCache::Transaction::DoPartialNetworkReadCompleted(int result) {
DCHECK(partial_);
// Go to the next range if nothing returned or return the result.
// TODO(shivanisha) Simplify this condition if possible. It was introduced
// in https://codereview.chromium.org/545101
if (result != 0 || truncated_ ||
!(partial_->IsLastRange() || mode_ == WRITE)) {
partial_->OnNetworkReadCompleted(result);
if (result == 0) {
// We need to move on to the next range.
if (network_trans_) {
ResetNetworkTransaction();
} else if (InWriters() && entry_->writers->network_transaction()) {
SaveNetworkTransactionInfo(*(entry_->writers->network_transaction()));
entry_->writers->ResetNetworkTransaction();
}
TransitionToState(STATE_START_PARTIAL_CACHE_VALIDATION);
} else {
TransitionToState(STATE_NONE);
}
return result;
}
// Request completed.
if (result == 0) {
DoneWithEntry(true);
}
TransitionToState(STATE_NONE);
return result;
}
int HttpCache::Transaction::DoNetworkRead() {
TRACE_EVENT0("io", "HttpCacheTransaction::DoNetworkRead");
TransitionToState(STATE_NETWORK_READ_COMPLETE);
return network_trans_->Read(read_buf_.get(), io_buf_len_, io_callback_);
}
int HttpCache::Transaction::DoNetworkReadComplete(int result) {
TRACE_EVENT0("io", "HttpCacheTransaction::DoNetworkReadComplete");
if (!cache_.get()) {
TransitionToState(STATE_NONE);
return ERR_UNEXPECTED;
}
if (partial_)
return DoPartialNetworkReadCompleted(result);
TransitionToState(STATE_NONE);
return result;
}
int HttpCache::Transaction::DoCacheReadData() {
TRACE_EVENT0("io", "HttpCacheTransaction::DoCacheReadData");
if (method_ == "HEAD") {
TransitionToState(STATE_NONE);
return 0;
}
DCHECK(entry_);
TransitionToState(STATE_CACHE_READ_DATA_COMPLETE);
if (net_log_.IsCapturing())
net_log_.BeginEvent(NetLogEventType::HTTP_CACHE_READ_DATA);
if (partial_) {
return partial_->CacheRead(entry_->disk_entry, read_buf_.get(), io_buf_len_,
io_callback_);
}
return entry_->disk_entry->ReadData(kResponseContentIndex, read_offset_,
read_buf_.get(), io_buf_len_,
io_callback_);
}
int HttpCache::Transaction::DoCacheReadDataComplete(int result) {
TRACE_EVENT0("io", "HttpCacheTransaction::DoCacheReadDataComplete");
if (net_log_.IsCapturing()) {
net_log_.EndEventWithNetErrorCode(NetLogEventType::HTTP_CACHE_READ_DATA,
result);
}
if (!cache_.get()) {
TransitionToState(STATE_NONE);
return ERR_UNEXPECTED;
}
if (partial_) {
// Partial requests are confusing to report in histograms because they may
// have multiple underlying requests.
UpdateCacheEntryStatus(CacheEntryStatus::ENTRY_OTHER);
return DoPartialCacheReadCompleted(result);
}
if (result > 0) {
read_offset_ += result;
} else if (result == 0) { // End of file.
DoneWithEntry(true);
} else {
return OnCacheReadError(result, false);
}
TransitionToState(STATE_NONE);
return result;
}
//-----------------------------------------------------------------------------
void HttpCache::Transaction::SetRequest(const NetLogWithSource& net_log) {
net_log_ = net_log;
// Reset the variables that might get set in this function. This is done
// because this function can be invoked multiple times for a transaction.
cache_entry_status_ = CacheEntryStatus::ENTRY_UNDEFINED;
external_validation_.Reset();
range_requested_ = false;
partial_.reset();
request_ = initial_request_;
custom_request_.reset();
effective_load_flags_ = request_->load_flags;
method_ = request_->method;
if (cache_->mode() == DISABLE)
effective_load_flags_ |= LOAD_DISABLE_CACHE;
// Some headers imply load flags. The order here is significant.
//
// LOAD_DISABLE_CACHE : no cache read or write
// LOAD_BYPASS_CACHE : no cache read
// LOAD_VALIDATE_CACHE : no cache read unless validation
//
// The former modes trump latter modes, so if we find a matching header we
// can stop iterating kSpecialHeaders.
//
static const struct {
const HeaderNameAndValue* search;
int load_flag;
} kSpecialHeaders[] = {
{ kPassThroughHeaders, LOAD_DISABLE_CACHE },
{ kForceFetchHeaders, LOAD_BYPASS_CACHE },
{ kForceValidateHeaders, LOAD_VALIDATE_CACHE },
};
bool range_found = false;
bool external_validation_error = false;
bool special_headers = false;
if (request_->extra_headers.HasHeader(HttpRequestHeaders::kRange))
range_found = true;
for (size_t i = 0; i < base::size(kSpecialHeaders); ++i) {
if (HeaderMatches(request_->extra_headers, kSpecialHeaders[i].search)) {
effective_load_flags_ |= kSpecialHeaders[i].load_flag;
special_headers = true;
break;
}
}
// Check for conditionalization headers which may correspond with a
// cache validation request.
for (size_t i = 0; i < base::size(kValidationHeaders); ++i) {
const ValidationHeaderInfo& info = kValidationHeaders[i];
std::string validation_value;
if (request_->extra_headers.GetHeader(
info.request_header_name, &validation_value)) {
if (!external_validation_.values[i].empty() ||
validation_value.empty()) {
external_validation_error = true;
}
external_validation_.values[i] = validation_value;
external_validation_.initialized = true;
}
}
if (range_found || special_headers || external_validation_.initialized) {
// Log the headers before request_ is modified.
std::string empty;
net_log_.AddEvent(
NetLogEventType::HTTP_CACHE_CALLER_REQUEST_HEADERS,
base::Bind(&HttpRequestHeaders::NetLogCallback,
base::Unretained(&request_->extra_headers), &empty));
}
// We don't support ranges and validation headers.
if (range_found && external_validation_.initialized) {
LOG(WARNING) << "Byte ranges AND validation headers found.";
effective_load_flags_ |= LOAD_DISABLE_CACHE;
}
// If there is more than one validation header, we can't treat this request as
// a cache validation, since we don't know for sure which header the server
// will give us a response for (and they could be contradictory).
if (external_validation_error) {
LOG(WARNING) << "Multiple or malformed validation headers found.";
effective_load_flags_ |= LOAD_DISABLE_CACHE;
}
if (range_found && !(effective_load_flags_ & LOAD_DISABLE_CACHE)) {
UpdateCacheEntryStatus(CacheEntryStatus::ENTRY_OTHER);
partial_.reset(new PartialData);
if (method_ == "GET" && partial_->Init(request_->extra_headers)) {
// We will be modifying the actual range requested to the server, so
// let's remove the header here.
// Note that custom_request_ is a shallow copy so will keep the same
// pointer to upload data stream as in the original request.
custom_request_.reset(new HttpRequestInfo(*request_));
custom_request_->extra_headers.RemoveHeader(HttpRequestHeaders::kRange);
request_ = custom_request_.get();
partial_->SetHeaders(custom_request_->extra_headers);
} else {
// The range is invalid or we cannot handle it properly.
VLOG(1) << "Invalid byte range found.";
effective_load_flags_ |= LOAD_DISABLE_CACHE;
partial_.reset(NULL);
}
}
}
bool HttpCache::Transaction::ShouldPassThrough() {
// We may have a null disk_cache if there is an error we cannot recover from,
// like not enough disk space, or sharing violations.
if (!cache_->disk_cache_.get())
return true;
if (effective_load_flags_ & LOAD_DISABLE_CACHE)
return true;
// Prevent resources whose origin is opaque from being cached.
// Blink's memory cache should take care of reusing resources
// within the current page load, but otherwise a resource with
// an opaque top-frame origin won’t be used again.
if (base::FeatureList::IsEnabled(features::kSplitCacheByTopFrameOrigin) &&
request_->top_frame_origin && request_->top_frame_origin->opaque())
return true;
if (method_ == "GET" || method_ == "HEAD")
return false;
if (method_ == "POST" && request_->upload_data_stream &&
request_->upload_data_stream->identifier()) {
return false;
}
if (method_ == "PUT" && request_->upload_data_stream)
return false;
if (method_ == "DELETE")
return false;
return true;
}
int HttpCache::Transaction::BeginCacheRead() {
// We don't support any combination of LOAD_ONLY_FROM_CACHE and byte ranges.
// TODO(jkarlin): Either handle this case or DCHECK.
if (response_.headers->response_code() == 206 || partial_) {
NOTREACHED();
TransitionToState(STATE_FINISH_HEADERS);
return ERR_CACHE_MISS;
}
// We don't have the whole resource.
if (truncated_) {
TransitionToState(STATE_FINISH_HEADERS);
return ERR_CACHE_MISS;
}
if (RequiresValidation() != VALIDATION_NONE) {
TransitionToState(STATE_FINISH_HEADERS);
return ERR_CACHE_MISS;
}
if (method_ == "HEAD")
FixHeadersForHead();
if (entry_->disk_entry->GetDataSize(kMetadataIndex) &&
!base::FeatureList::IsEnabled(net::features::kIsolatedCodeCache)) {
TransitionToState(STATE_CACHE_READ_METADATA);
} else {
TransitionToState(STATE_FINISH_HEADERS);
}
return OK;
}
int HttpCache::Transaction::BeginCacheValidation() {
DCHECK_EQ(mode_, READ_WRITE);
ValidationType required_validation = RequiresValidation();
bool skip_validation = (required_validation == VALIDATION_NONE);
bool needs_stale_while_revalidate_cache_update = false;
if ((effective_load_flags_ & LOAD_SUPPORT_ASYNC_REVALIDATION) &&
required_validation == VALIDATION_ASYNCHRONOUS) {
DCHECK_EQ(request_->method, "GET");
skip_validation = true;
response_.async_revalidation_requested = true;
needs_stale_while_revalidate_cache_update =
response_.stale_revalidate_timeout.is_null();
}
if (method_ == "HEAD" &&
(truncated_ || response_.headers->response_code() == 206)) {
DCHECK(!partial_);
if (skip_validation) {
TransitionToState(STATE_SETUP_ENTRY_FOR_READ);
return OK;
}
// Bail out!
TransitionToState(STATE_SEND_REQUEST);
mode_ = NONE;
return OK;
}
if (truncated_) {
// Truncated entries can cause partial gets, so we shouldn't record this
// load in histograms.
UpdateCacheEntryStatus(CacheEntryStatus::ENTRY_OTHER);
skip_validation = !partial_->initial_validation();
}
// If this is the first request (!reading_) of a 206 entry (is_sparse_) that
// doesn't actually cover the entire file (which with !reading would require
// partial->IsLastRange()), and the user is requesting the whole thing
// (!partial_->range_requested()), make sure to validate the first chunk,
// since afterwards it will be too late if it's actually out-of-date (or the
// server bungles invalidation). This is limited to the whole-file request
// as a targeted fix for https://crbug.com/888742 while avoiding extra
// requests in other cases, but the problem can occur more generally as well;
// it's just a lot less likely with applications actively using ranges.
// See https://crbug.com/902724 for the more general case.
bool first_read_of_full_from_partial =
is_sparse_ && !reading_ &&
(partial_ && !partial_->range_requested() && !partial_->IsLastRange());
if (partial_ && (is_sparse_ || truncated_) &&
(!partial_->IsCurrentRangeCached() || invalid_range_ ||
first_read_of_full_from_partial)) {
// Force revalidation for sparse or truncated entries. Note that we don't
// want to ignore the regular validation logic just because a byte range was
// part of the request.
skip_validation = false;
}
if (skip_validation) {
UpdateCacheEntryStatus(CacheEntryStatus::ENTRY_USED);
TransitionToState(needs_stale_while_revalidate_cache_update
? STATE_CACHE_UPDATE_STALE_WHILE_REVALIDATE_TIMEOUT
: STATE_SETUP_ENTRY_FOR_READ);
return OK;
} else {
// Make the network request conditional, to see if we may reuse our cached
// response. If we cannot do so, then we just resort to a normal fetch.
// Our mode remains READ_WRITE for a conditional request. Even if the
// conditionalization fails, we don't switch to WRITE mode until we
// know we won't be falling back to using the cache entry in the
// LOAD_FROM_CACHE_IF_OFFLINE case.
if (!ConditionalizeRequest()) {
couldnt_conditionalize_request_ = true;
UpdateCacheEntryStatus(CacheEntryStatus::ENTRY_CANT_CONDITIONALIZE);
if (partial_)
return DoRestartPartialRequest();
DCHECK_NE(206, response_.headers->response_code());
}
TransitionToState(STATE_SEND_REQUEST);
}
return OK;
}
int HttpCache::Transaction::BeginPartialCacheValidation() {
DCHECK_EQ(mode_, READ_WRITE);
if (response_.headers->response_code() != 206 && !partial_ && !truncated_)
return BeginCacheValidation();
// Partial requests should not be recorded in histograms.
UpdateCacheEntryStatus(CacheEntryStatus::ENTRY_OTHER);
if (method_ == "HEAD")
return BeginCacheValidation();
if (!range_requested_) {
// The request is not for a range, but we have stored just ranges.
partial_.reset(new PartialData());
partial_->SetHeaders(request_->extra_headers);
if (!custom_request_.get()) {
custom_request_.reset(new HttpRequestInfo(*request_));
request_ = custom_request_.get();
}
}
TransitionToState(STATE_CACHE_QUERY_DATA);
return OK;
}
// This should only be called once per request.
int HttpCache::Transaction::ValidateEntryHeadersAndContinue() {
DCHECK_EQ(mode_, READ_WRITE);
if (!partial_->UpdateFromStoredHeaders(response_.headers.get(),
entry_->disk_entry, truncated_,
cache_->IsWritingInProgress(entry_))) {
return DoRestartPartialRequest();
}
if (response_.headers->response_code() == 206)
is_sparse_ = true;
if (!partial_->IsRequestedRangeOK()) {
// The stored data is fine, but the request may be invalid.
invalid_range_ = true;
}
TransitionToState(STATE_START_PARTIAL_CACHE_VALIDATION);
return OK;
}
int HttpCache::Transaction::BeginExternallyConditionalizedRequest() {
DCHECK_EQ(UPDATE, mode_);
DCHECK(external_validation_.initialized);
for (size_t i = 0; i < base::size(kValidationHeaders); i++) {
if (external_validation_.values[i].empty())
continue;
// Retrieve either the cached response's "etag" or "last-modified" header.
std::string validator;
response_.headers->EnumerateHeader(
NULL,
kValidationHeaders[i].related_response_header_name,
&validator);
if (response_.headers->response_code() != 200 || truncated_ ||
validator.empty() || validator != external_validation_.values[i]) {
// The externally conditionalized request is not a validation request
// for our existing cache entry. Proceed with caching disabled.
UpdateCacheEntryStatus(CacheEntryStatus::ENTRY_OTHER);
DoneWithEntry(true);
}
}
TransitionToState(STATE_SEND_REQUEST);
return OK;
}
int HttpCache::Transaction::RestartNetworkRequest() {
DCHECK(mode_ & WRITE || mode_ == NONE);
DCHECK(network_trans_.get());
DCHECK_EQ(STATE_NONE, next_state_);
next_state_ = STATE_SEND_REQUEST_COMPLETE;
int rv = network_trans_->RestartIgnoringLastError(io_callback_);
if (rv != ERR_IO_PENDING)
return DoLoop(rv);
return rv;
}
int HttpCache::Transaction::RestartNetworkRequestWithCertificate(
scoped_refptr<X509Certificate> client_cert,
scoped_refptr<SSLPrivateKey> client_private_key) {
DCHECK(mode_ & WRITE || mode_ == NONE);
DCHECK(network_trans_.get());
DCHECK_EQ(STATE_NONE, next_state_);
next_state_ = STATE_SEND_REQUEST_COMPLETE;
int rv = network_trans_->RestartWithCertificate(
std::move(client_cert), std::move(client_private_key), io_callback_);
if (rv != ERR_IO_PENDING)
return DoLoop(rv);
return rv;
}
int HttpCache::Transaction::RestartNetworkRequestWithAuth(
const AuthCredentials& credentials) {
DCHECK(mode_ & WRITE || mode_ == NONE);
DCHECK(network_trans_.get());
DCHECK_EQ(STATE_NONE, next_state_);
next_state_ = STATE_SEND_REQUEST_COMPLETE;
int rv = network_trans_->RestartWithAuth(credentials, io_callback_);
if (rv != ERR_IO_PENDING)
return DoLoop(rv);
return rv;
}
ValidationType HttpCache::Transaction::RequiresValidation() {
// TODO(darin): need to do more work here:
// - make sure we have a matching request method
// - watch out for cached responses that depend on authentication
if (!(effective_load_flags_ & LOAD_SKIP_VARY_CHECK) &&
response_.vary_data.is_valid() &&
!response_.vary_data.MatchesRequest(*request_,
*response_.headers.get())) {
vary_mismatch_ = true;
validation_cause_ = VALIDATION_CAUSE_VARY_MISMATCH;
return VALIDATION_SYNCHRONOUS;
}
if (effective_load_flags_ & LOAD_SKIP_CACHE_VALIDATION)
return VALIDATION_NONE;
if (response_.unused_since_prefetch &&
!(effective_load_flags_ & LOAD_PREFETCH) &&
response_.headers->GetCurrentAge(
response_.request_time, response_.response_time,
cache_->clock_->Now()) < TimeDelta::FromMinutes(kPrefetchReuseMins)) {
// The first use of a resource after prefetch within a short window skips
// validation.
return VALIDATION_NONE;
}
if (effective_load_flags_ & LOAD_VALIDATE_CACHE) {
validation_cause_ = VALIDATION_CAUSE_VALIDATE_FLAG;
return VALIDATION_SYNCHRONOUS;
}
if (method_ == "PUT" || method_ == "DELETE")
return VALIDATION_SYNCHRONOUS;
ValidationType validation_required_by_headers =
response_.headers->RequiresValidation(response_.request_time,
response_.response_time,
cache_->clock_->Now());
if (validation_required_by_headers != VALIDATION_NONE) {
HttpResponseHeaders::FreshnessLifetimes lifetimes =
response_.headers->GetFreshnessLifetimes(response_.response_time);
if (lifetimes.freshness == base::TimeDelta()) {
validation_cause_ = VALIDATION_CAUSE_ZERO_FRESHNESS;
} else {
validation_cause_ = VALIDATION_CAUSE_STALE;
stale_entry_freshness_ = lifetimes.freshness;
stale_entry_age_ = response_.headers->GetCurrentAge(
response_.request_time, response_.response_time,
cache_->clock_->Now());
}
}
if (validation_required_by_headers == VALIDATION_ASYNCHRONOUS) {
// Asynchronous revalidation is only supported for GET methods.
if (request_->method != "GET")
return VALIDATION_SYNCHRONOUS;
// If the timeout on the staleness revalidation is set don't hand out
// a resource that hasn't been async validated.
if (!response_.stale_revalidate_timeout.is_null() &&
response_.stale_revalidate_timeout < cache_->clock_->Now()) {
return VALIDATION_SYNCHRONOUS;
}
}
return validation_required_by_headers;
}
bool HttpCache::Transaction::IsResponseConditionalizable(
std::string* etag_value,
std::string* last_modified_value) const {
DCHECK(response_.headers.get());
// This only makes sense for cached 200 or 206 responses.
if (response_.headers->response_code() != 200 &&
response_.headers->response_code() != 206) {
return false;
}
// Just use the first available ETag and/or Last-Modified header value.
// TODO(darin): Or should we use the last?
if (response_.headers->GetHttpVersion() >= HttpVersion(1, 1))
response_.headers->EnumerateHeader(NULL, "etag", etag_value);
response_.headers->EnumerateHeader(NULL, "last-modified",
last_modified_value);
if (etag_value->empty() && last_modified_value->empty())
</