// Copyright (c) 2011 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"
#if defined(OS_POSIX)
#include <unistd.h>
#endif
#include <string>
#include "base/compiler_specific.h"
#include "base/memory/ref_counted.h"
#include "base/metrics/field_trial.h"
#include "base/metrics/histogram.h"
#include "base/string_util.h"
#include "base/time.h"
#include "net/base/cert_status_flags.h"
#include "net/base/io_buffer.h"
#include "net/base/load_flags.h"
#include "net/base/net_errors.h"
#include "net/base/net_log.h"
#include "net/base/network_delegate.h"
#include "net/base/ssl_cert_request_info.h"
#include "net/base/ssl_config_service.h"
#include "net/disk_cache/disk_cache.h"
#include "net/http/disk_cache_based_ssl_host_info.h"
#include "net/http/http_network_session.h"
#include "net/http/http_request_info.h"
#include "net/http/http_response_headers.h"
#include "net/http/http_transaction.h"
#include "net/http/http_util.h"
#include "net/http/partial_data.h"
using base::Time;
namespace net {
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 (LowerCaseEqualsASCII(v.value_begin(), v.value_end(), search->value))
return true;
}
}
return false;
}
//-----------------------------------------------------------------------------
HttpCache::Transaction::Transaction(HttpCache* cache)
: next_state_(STATE_NONE),
request_(NULL),
cache_(cache->AsWeakPtr()),
entry_(NULL),
new_entry_(NULL),
network_trans_(NULL),
callback_(NULL),
new_response_(NULL),
mode_(NONE),
target_state_(STATE_NONE),
reading_(false),
invalid_range_(false),
truncated_(false),
is_sparse_(false),
server_responded_206_(false),
cache_pending_(false),
read_offset_(0),
effective_load_flags_(0),
write_len_(0),
final_upload_progress_(0),
ALLOW_THIS_IN_INITIALIZER_LIST(
io_callback_(this, &Transaction::OnIOComplete)),
ALLOW_THIS_IN_INITIALIZER_LIST(
cache_callback_(new CancelableCompletionCallback<Transaction>(
this, &Transaction::OnIOComplete))),
ALLOW_THIS_IN_INITIALIZER_LIST(
write_headers_callback_(new CancelableCompletionCallback<Transaction>(
this, &Transaction::OnIOComplete))) {
COMPILE_ASSERT(HttpCache::Transaction::kNumValidationHeaders ==
arraysize(kValidationHeaders),
Invalid_number_of_validation_headers);
}
HttpCache::Transaction::~Transaction() {
// We may have to issue another IO, but we should never invoke the callback_
// after this point.
callback_ = NULL;
if (cache_) {
if (entry_) {
bool cancel_request = reading_;
if (cancel_request) {
if (partial_.get()) {
entry_->disk_entry->CancelSparseIO();
} else {
cancel_request &= (response_.headers->response_code() == 200);
}
}
cache_->DoneWithEntry(entry_, this, cancel_request);
} else if (cache_pending_) {
cache_->RemovePendingTransaction(this);
}
}
// If there is an outstanding callback, mark it as cancelled so running it
// does nothing.
cache_callback_->Cancel();
write_headers_callback_->Cancel();
// We could still have a cache read or write in progress, so we just null the
// cache_ pointer to signal that we are dead. See DoCacheReadCompleted.
cache_.reset();
}
int HttpCache::Transaction::WriteMetadata(IOBuffer* buf, int buf_len,
CompletionCallback* callback) {
DCHECK(buf);
DCHECK_GT(buf_len, 0);
DCHECK(callback);
if (!cache_ || !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,
callback, true);
}
bool HttpCache::Transaction::AddTruncatedFlag() {
DCHECK(mode_ & WRITE);
// Don't set the flag for sparse entries.
if (partial_.get() && !truncated_)
return true;
if (!CanResume(true))
return false;
truncated_ = true;
target_state_ = STATE_NONE;
next_state_ = STATE_CACHE_WRITE_TRUNCATED_RESPONSE;
DoLoop(OK);
return true;
}
LoadState HttpCache::Transaction::GetWriterLoadState() const {
if (network_trans_.get())
return network_trans_->GetLoadState();
if (entry_ || !request_)
return LOAD_STATE_IDLE;
return LOAD_STATE_WAITING_FOR_CACHE;
}
const BoundNetLog& HttpCache::Transaction::net_log() const {
return net_log_;
}
int HttpCache::Transaction::Start(const HttpRequestInfo* request,
CompletionCallback* callback,
const BoundNetLog& net_log) {
DCHECK(request);
DCHECK(callback);
// Ensure that we only have one asynchronous call at a time.
DCHECK(!callback_);
DCHECK(!reading_);
DCHECK(!network_trans_.get());
DCHECK(!entry_);
if (!cache_)
return ERR_UNEXPECTED;
SetRequest(net_log, request);
// 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_ = callback;
return rv;
}
int HttpCache::Transaction::RestartIgnoringLastError(
CompletionCallback* callback) {
DCHECK(callback);
// Ensure that we only have one asynchronous call at a time.
DCHECK(!callback_);
if (!cache_)
return ERR_UNEXPECTED;
int rv = RestartNetworkRequest();
if (rv == ERR_IO_PENDING)
callback_ = callback;
return rv;
}
int HttpCache::Transaction::RestartWithCertificate(
X509Certificate* client_cert,
CompletionCallback* callback) {
DCHECK(callback);
// Ensure that we only have one asynchronous call at a time.
DCHECK(!callback_);
if (!cache_)
return ERR_UNEXPECTED;
int rv = RestartNetworkRequestWithCertificate(client_cert);
if (rv == ERR_IO_PENDING)
callback_ = callback;
return rv;
}
int HttpCache::Transaction::RestartWithAuth(
const string16& username,
const string16& password,
CompletionCallback* callback) {
DCHECK(auth_response_.headers);
DCHECK(callback);
// Ensure that we only have one asynchronous call at a time.
DCHECK(!callback_);
if (!cache_)
return ERR_UNEXPECTED;
// Clear the intermediate response since we are going to start over.
auth_response_ = HttpResponseInfo();
int rv = RestartNetworkRequestWithAuth(username, password);
if (rv == ERR_IO_PENDING)
callback_ = 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,
CompletionCallback* callback) {
DCHECK(buf);
DCHECK_GT(buf_len, 0);
DCHECK(callback);
DCHECK(!callback_);
if (!cache_)
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 && mode_ != NONE) {
DCHECK(mode_ & WRITE);
DoneWritingToEntry(mode_ == READ_WRITE);
mode_ = NONE;
}
reading_ = true;
int rv;
switch (mode_) {
case READ_WRITE:
DCHECK(partial_.get());
if (!network_trans_.get()) {
// We are just reading from the cache, but we may be writing later.
rv = ReadFromEntry(buf, buf_len);
break;
}
case NONE:
case WRITE:
DCHECK(network_trans_.get());
rv = ReadFromNetwork(buf, buf_len);
break;
case READ:
rv = ReadFromEntry(buf, buf_len);
break;
default:
NOTREACHED();
rv = ERR_FAILED;
}
if (rv == ERR_IO_PENDING) {
DCHECK(!callback_);
callback_ = callback;
}
return rv;
}
void HttpCache::Transaction::StopCaching() {
}
const HttpResponseInfo* HttpCache::Transaction::GetResponseInfo() const {
// Null headers means we encountered an error or haven't a response yet
if (auth_response_.headers)
return &auth_response_;
return (response_.headers || response_.ssl_info.cert ||
response_.cert_request_info) ? &response_ : NULL;
}
LoadState HttpCache::Transaction::GetLoadState() const {
LoadState state = GetWriterLoadState();
if (state != LOAD_STATE_WAITING_FOR_CACHE)
return state;
if (cache_)
return cache_->GetLoadStateForPendingTransaction(this);
return LOAD_STATE_IDLE;
}
uint64 HttpCache::Transaction::GetUploadProgress() const {
if (network_trans_.get())
return network_trans_->GetUploadProgress();
return final_upload_progress_;
}
//-----------------------------------------------------------------------------
void HttpCache::Transaction::DoCallback(int rv) {
DCHECK(rv != ERR_IO_PENDING);
DCHECK(callback_);
// Since Run may result in Read being called, clear callback_ up front.
CompletionCallback* c = callback_;
callback_ = NULL;
c->Run(rv);
}
int HttpCache::Transaction::HandleResult(int rv) {
DCHECK(rv != ERR_IO_PENDING);
if (callback_)
DoCallback(rv);
return rv;
}
int HttpCache::Transaction::DoLoop(int result) {
DCHECK(next_state_ != STATE_NONE);
int rv = result;
do {
State state = next_state_;
next_state_ = STATE_NONE;
switch (state) {
case STATE_GET_BACKEND:
DCHECK_EQ(OK, rv);
rv = DoGetBackend();
break;
case STATE_GET_BACKEND_COMPLETE:
rv = DoGetBackendComplete(rv);
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_NETWORK_READ:
DCHECK_EQ(OK, rv);
rv = DoNetworkRead();
break;
case STATE_NETWORK_READ_COMPLETE:
rv = DoNetworkReadComplete(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_CREATE_ENTRY:
DCHECK_EQ(OK, rv);
rv = DoCreateEntry();
break;
case STATE_CREATE_ENTRY_COMPLETE:
rv = DoCreateEntryComplete(rv);
break;
case STATE_DOOM_ENTRY:
DCHECK_EQ(OK, rv);
rv = DoDoomEntry();
break;
case STATE_DOOM_ENTRY_COMPLETE:
rv = DoDoomEntryComplete(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_NOTIFY_BEFORE_SEND_HEADERS:
DCHECK_EQ(OK, rv);
rv = DoNotifyBeforeSendHeaders();
break;
case STATE_NOTIFY_BEFORE_SEND_HEADERS_COMPLETE:
rv = DoNotifyBeforeSendHeadersComplete(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_UPDATE_CACHED_RESPONSE:
DCHECK_EQ(OK, rv);
rv = DoUpdateCachedResponse();
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_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_RESPONSE:
DCHECK_EQ(OK, rv);
rv = DoCacheReadResponse();
break;
case STATE_CACHE_READ_RESPONSE_COMPLETE:
rv = DoCacheReadResponseComplete(rv);
break;
case STATE_CACHE_WRITE_RESPONSE:
DCHECK_EQ(OK, rv);
rv = DoCacheWriteResponse();
break;
case STATE_CACHE_WRITE_TRUNCATED_RESPONSE:
DCHECK_EQ(OK, rv);
rv = DoCacheWriteTruncatedResponse();
break;
case STATE_CACHE_WRITE_RESPONSE_COMPLETE:
rv = DoCacheWriteResponseComplete(rv);
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_CACHE_QUERY_DATA:
DCHECK_EQ(OK, rv);
rv = DoCacheQueryData();
break;
case STATE_CACHE_QUERY_DATA_COMPLETE:
rv = DoCacheQueryDataComplete(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_CACHE_WRITE_DATA:
rv = DoCacheWriteData(rv);
break;
case STATE_CACHE_WRITE_DATA_COMPLETE:
rv = DoCacheWriteDataComplete(rv);
break;
default:
NOTREACHED() << "bad state";
rv = ERR_FAILED;
break;
}
} while (rv != ERR_IO_PENDING && next_state_ != STATE_NONE);
if (rv != ERR_IO_PENDING)
HandleResult(rv);
return rv;
}
int HttpCache::Transaction::DoGetBackend() {
cache_pending_ = true;
next_state_ = STATE_GET_BACKEND_COMPLETE;
net_log_.BeginEvent(NetLog::TYPE_HTTP_CACHE_GET_BACKEND, NULL);
return cache_->GetBackendForTransaction(this);
}
int HttpCache::Transaction::DoGetBackendComplete(int result) {
DCHECK(result == OK || result == ERR_FAILED);
net_log_.EndEventWithNetErrorCode(NetLog::TYPE_HTTP_CACHE_GET_BACKEND,
result);
cache_pending_ = false;
if (!ShouldPassThrough()) {
cache_key_ = cache_->GenerateCacheKey(request_);
// Requested cache access mode.
if (effective_load_flags_ & LOAD_ONLY_FROM_CACHE) {
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;
}
}
}
// 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)
return ERR_CACHE_MISS;
if (mode_ == NONE) {
if (partial_.get())
partial_->RestoreHeaders(&custom_request_->extra_headers);
next_state_ = STATE_SEND_REQUEST;
} else {
next_state_ = STATE_INIT_ENTRY;
}
return OK;
}
int HttpCache::Transaction::DoSendRequest() {
DCHECK(mode_ & WRITE || mode_ == NONE);
DCHECK(!network_trans_.get());
// Create a network transaction.
int rv = cache_->network_layer_->CreateTransaction(&network_trans_);
if (rv != OK)
return rv;
next_state_ = STATE_SEND_REQUEST_COMPLETE;
rv = network_trans_->Start(request_, &io_callback_, net_log_);
return rv;
}
int HttpCache::Transaction::DoSendRequestComplete(int result) {
if (!cache_)
return ERR_UNEXPECTED;
if (result == OK) {
next_state_ = STATE_SUCCESSFUL_SEND_REQUEST;
return OK;
}
if (IsCertificateError(result)) {
const HttpResponseInfo* response = network_trans_->GetResponseInfo();
// If we get a certificate error, then there is a certificate in ssl_info,
// so GetResponseInfo() should never returns NULL here.
DCHECK(response);
response_.ssl_info = response->ssl_info;
} else if (result == ERR_SSL_CLIENT_AUTH_CERT_NEEDED) {
const HttpResponseInfo* response = network_trans_->GetResponseInfo();
DCHECK(response);
response_.cert_request_info = response->cert_request_info;
}
return result;
}
// We received the response headers and there is no error.
int HttpCache::Transaction::DoSuccessfulSendRequest() {
DCHECK(!new_response_);
const HttpResponseInfo* new_response = network_trans_->GetResponseInfo();
if (new_response->headers->response_code() == 401 ||
new_response->headers->response_code() == 407) {
auth_response_ = *new_response;
return OK;
}
new_response_ = new_response;
if (!ValidatePartialResponse(&server_responded_206_) &&
!auth_response_.headers) {
// 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.
response_ = HttpResponseInfo();
network_trans_.reset();
new_response_ = NULL;
next_state_ = STATE_SEND_REQUEST;
return OK;
}
if (server_responded_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.
DoneWritingToEntry(false);
}
if (new_response_->headers->response_code() == 416) {
DCHECK_EQ(NONE, mode_);
response_ = *new_response_;
return OK;
}
// Are we expecting a response to a conditional query?
if (mode_ == READ_WRITE || mode_ == UPDATE) {
if (new_response->headers->response_code() == 304 ||
server_responded_206_) {
next_state_ = STATE_UPDATE_CACHED_RESPONSE;
return OK;
}
mode_ = WRITE;
}
next_state_ = STATE_OVERWRITE_CACHED_RESPONSE;
return OK;
}
int HttpCache::Transaction::DoNetworkRead() {
next_state_ = STATE_NETWORK_READ_COMPLETE;
return network_trans_->Read(read_buf_, io_buf_len_, &io_callback_);
}
int HttpCache::Transaction::DoNetworkReadComplete(int result) {
DCHECK(mode_ & WRITE || mode_ == NONE);
if (!cache_)
return ERR_UNEXPECTED;
// If there is an error and we are saving the data, just tell the user about
// it and wait until the destructor runs to see if we can keep the data.
if (mode_ != NONE && result < 0)
return result;
next_state_ = STATE_CACHE_WRITE_DATA;
return result;
}
int HttpCache::Transaction::DoInitEntry() {
DCHECK(!new_entry_);
if (!cache_)
return ERR_UNEXPECTED;
if (mode_ == WRITE) {
next_state_ = STATE_DOOM_ENTRY;
return OK;
}
next_state_ = STATE_OPEN_ENTRY;
return OK;
}
int HttpCache::Transaction::DoOpenEntry() {
DCHECK(!new_entry_);
next_state_ = STATE_OPEN_ENTRY_COMPLETE;
cache_pending_ = true;
net_log_.BeginEvent(NetLog::TYPE_HTTP_CACHE_OPEN_ENTRY, NULL);
return cache_->OpenEntry(cache_key_, &new_entry_, this);
}
int HttpCache::Transaction::DoOpenEntryComplete(int result) {
// 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(NetLog::TYPE_HTTP_CACHE_OPEN_ENTRY, result);
cache_pending_ = false;
if (result == OK) {
next_state_ = STATE_ADD_TO_ENTRY;
return OK;
}
if (result == ERR_CACHE_RACE) {
next_state_ = STATE_INIT_ENTRY;
return OK;
}
if (mode_ == READ_WRITE) {
mode_ = WRITE;
next_state_ = STATE_CREATE_ENTRY;
return OK;
}
if (mode_ == UPDATE) {
// There is no cache entry to update; proceed without caching.
mode_ = NONE;
next_state_ = STATE_SEND_REQUEST;
return OK;
}
if (cache_->mode() == PLAYBACK)
DVLOG(1) << "Playback Cache Miss: " << request_->url;
// The entry does not exist, and we are not permitted to create a new entry,
// so we must fail.
return ERR_CACHE_MISS;
}
int HttpCache::Transaction::DoCreateEntry() {
DCHECK(!new_entry_);
next_state_ = STATE_CREATE_ENTRY_COMPLETE;
cache_pending_ = true;
net_log_.BeginEvent(NetLog::TYPE_HTTP_CACHE_CREATE_ENTRY, NULL);
return cache_->CreateEntry(cache_key_, &new_entry_, this);
}
int HttpCache::Transaction::DoCreateEntryComplete(int result) {
// 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(NetLog::TYPE_HTTP_CACHE_CREATE_ENTRY,
result);
cache_pending_ = false;
next_state_ = STATE_ADD_TO_ENTRY;
if (result == ERR_CACHE_RACE) {
next_state_ = STATE_INIT_ENTRY;
return OK;
}
if (result != OK) {
// 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";
mode_ = NONE;
if (partial_.get())
partial_->RestoreHeaders(&custom_request_->extra_headers);
next_state_ = STATE_SEND_REQUEST;
}
return OK;
}
int HttpCache::Transaction::DoDoomEntry() {
next_state_ = STATE_DOOM_ENTRY_COMPLETE;
cache_pending_ = true;
net_log_.BeginEvent(NetLog::TYPE_HTTP_CACHE_DOOM_ENTRY, NULL);
return cache_->DoomEntry(cache_key_, this);
}
int HttpCache::Transaction::DoDoomEntryComplete(int result) {
net_log_.EndEventWithNetErrorCode(NetLog::TYPE_HTTP_CACHE_DOOM_ENTRY, result);
next_state_ = STATE_CREATE_ENTRY;
cache_pending_ = false;
if (result == ERR_CACHE_RACE)
next_state_ = STATE_INIT_ENTRY;
return OK;
}
int HttpCache::Transaction::DoAddToEntry() {
DCHECK(new_entry_);
cache_pending_ = true;
next_state_ = STATE_ADD_TO_ENTRY_COMPLETE;
net_log_.BeginEvent(NetLog::TYPE_HTTP_CACHE_ADD_TO_ENTRY, NULL);
DCHECK(entry_lock_waiting_since_.is_null());
entry_lock_waiting_since_ = base::TimeTicks::Now();
return cache_->AddTransactionToEntry(new_entry_, this);
}
int HttpCache::Transaction::DoAddToEntryComplete(int result) {
net_log_.EndEventWithNetErrorCode(NetLog::TYPE_HTTP_CACHE_ADD_TO_ENTRY,
result);
const base::TimeDelta entry_lock_wait =
base::TimeTicks::Now() - entry_lock_waiting_since_;
UMA_HISTOGRAM_TIMES("HttpCache.EntryLockWait", entry_lock_wait);
static const bool prefetching_fieldtrial =
base::FieldTrialList::Find("Prefetch") &&
!base::FieldTrialList::Find("Prefetch")->group_name().empty();
if (prefetching_fieldtrial) {
UMA_HISTOGRAM_TIMES(
base::FieldTrial::MakeName("HttpCache.EntryLockWait", "Prefetch"),
entry_lock_wait);
}
entry_lock_waiting_since_ = base::TimeTicks();
DCHECK(new_entry_);
cache_pending_ = false;
if (result == ERR_CACHE_RACE) {
new_entry_ = NULL;
next_state_ = STATE_INIT_ENTRY;
return OK;
}
if (result != OK) {
// If there is a failure, the cache should have taken care of new_entry_.
NOTREACHED();
new_entry_ = NULL;
return result;
}
entry_ = new_entry_;
new_entry_ = NULL;
if (mode_ == WRITE) {
if (partial_.get())
partial_->RestoreHeaders(&custom_request_->extra_headers);
next_state_ = STATE_SEND_REQUEST;
} else {
// We have to read the headers from the cached entry.
DCHECK(mode_ & READ_META);
next_state_ = STATE_CACHE_READ_RESPONSE;
}
return OK;
}
int HttpCache::Transaction::DoNotifyBeforeSendHeaders() {
// Balanced in DoNotifyBeforeSendHeadersComplete.
cache_callback_->AddRef();
next_state_ = STATE_NOTIFY_BEFORE_SEND_HEADERS_COMPLETE;
if (cache_->GetSession() && cache_->GetSession()->network_delegate()) {
// TODO(mpcomplete): need to be able to modify these headers.
HttpRequestHeaders headers = request_->extra_headers;
return cache_->GetSession()->network_delegate()->NotifyBeforeSendHeaders(
request_->request_id, cache_callback_, &headers);
}
return OK;
}
int HttpCache::Transaction::DoNotifyBeforeSendHeadersComplete(int result) {
cache_callback_->Release(); // Balanced in DoNotifyBeforeSendHeaders.
// 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.
//
if (result == net::OK) {
switch (mode_) {
case READ:
result = BeginCacheRead();
break;
case READ_WRITE:
result = BeginPartialCacheValidation();
break;
case UPDATE:
result = BeginExternallyConditionalizedRequest();
break;
case WRITE:
default:
NOTREACHED();
result = ERR_FAILED;
}
}
return result;
}
// We may end up here multiple times for a given request.
int HttpCache::Transaction::DoStartPartialCacheValidation() {
if (mode_ == NONE)
return OK;
next_state_ = 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.
if (mode_ & WRITE) {
DoneWritingToEntry(true);
} else {
cache_->DoneReadingFromEntry(entry_, this);
entry_ = NULL;
}
return result;
}
if (result < 0)
return result;
partial_->PrepareCacheValidation(entry_->disk_entry,
&custom_request_->extra_headers);
if (reading_ && partial_->IsCurrentRangeCached()) {
next_state_ = STATE_CACHE_READ_DATA;
return OK;
}
return BeginCacheValidation();
}
// We received 304 or 206 and we want to update the cached response headers.
int HttpCache::Transaction::DoUpdateCachedResponse() {
next_state_ = STATE_UPDATE_CACHED_RESPONSE_COMPLETE;
int rv = OK;
// Update cached response based on headers in new_response.
// TODO(wtc): should we update cached certificate (response_.ssl_info), too?
response_.headers->Update(*new_response_->headers);
response_.response_time = new_response_->response_time;
response_.request_time = new_response_->request_time;
if (response_.headers->HasHeaderValue("cache-control", "no-store")) {
int ret = cache_->DoomEntry(cache_key_, NULL);
DCHECK_EQ(OK, ret);
} else {
// If we are already reading, we already updated the headers for this
// request; doing it again will change Content-Length.
if (!reading_) {
target_state_ = STATE_UPDATE_CACHED_RESPONSE_COMPLETE;
next_state_ = STATE_CACHE_WRITE_RESPONSE;
rv = OK;
}
}
return rv;
}
int HttpCache::Transaction::DoUpdateCachedResponseComplete(int result) {
if (mode_ == UPDATE) {
DCHECK(!server_responded_206_);
// We got a "not modified" response and already updated the corresponding
// cache entry above.
//
// By closing the cached entry now, we make sure that the 304 rather than
// the cached 200 response, is what will be returned to the user.
DoneWritingToEntry(true);
} else if (entry_ && !server_responded_206_) {
DCHECK_EQ(READ_WRITE, mode_);
if (!partial_.get() || partial_->IsLastRange()) {
cache_->ConvertWriterToReader(entry_);
mode_ = READ;
}
// We no longer need the network transaction, so destroy it.
final_upload_progress_ = network_trans_->GetUploadProgress();
network_trans_.reset();
} else if (entry_ && server_responded_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.
network_trans_.reset();
new_response_ = NULL;
next_state_ = STATE_START_PARTIAL_CACHE_VALIDATION;
partial_->SetRangeToStartDownload();
return OK;
}
next_state_ = STATE_OVERWRITE_CACHED_RESPONSE;
return OK;
}
int HttpCache::Transaction::DoOverwriteCachedResponse() {
if (mode_ & READ) {
next_state_ = STATE_PARTIAL_HEADERS_RECEIVED;
return OK;
}
// We change the value of Content-Length for partial content.
if (server_responded_206_ && partial_.get())
partial_->FixContentLength(new_response_->headers);
response_ = *new_response_;
if (server_responded_206_ && !CanResume(false)) {
// There is no point in storing this resource because it will never be used.
DoneWritingToEntry(false);
if (partial_.get())
partial_->FixResponseHeaders(response_.headers, true);
next_state_ = STATE_PARTIAL_HEADERS_RECEIVED;
return OK;
}
target_state_ = STATE_TRUNCATE_CACHED_DATA;
next_state_ = truncated_ ? STATE_CACHE_WRITE_TRUNCATED_RESPONSE :
STATE_CACHE_WRITE_RESPONSE;
return OK;
}
int HttpCache::Transaction::DoTruncateCachedData() {
next_state_ = STATE_TRUNCATE_CACHED_DATA_COMPLETE;
cache_callback_->AddRef(); // Balanced in DoTruncateCachedDataComplete.
if (!entry_)
return OK;
if (net_log_.IsLoggingAllEvents())
net_log_.BeginEvent(NetLog::TYPE_HTTP_CACHE_WRITE_DATA, NULL);
// Truncate the stream.
return WriteToEntry(kResponseContentIndex, 0, NULL, 0, cache_callback_);
}
int HttpCache::Transaction::DoTruncateCachedDataComplete(int result) {
if (net_log_.IsLoggingAllEvents() && entry_) {
net_log_.EndEventWithNetErrorCode(NetLog::TYPE_HTTP_CACHE_WRITE_DATA,
result);
}
// Balance the AddRef from DoTruncateCachedData.
cache_callback_->Release();
next_state_ = STATE_TRUNCATE_CACHED_METADATA;
return OK;
}
int HttpCache::Transaction::DoTruncateCachedMetadata() {
next_state_ = STATE_TRUNCATE_CACHED_METADATA_COMPLETE;
cache_callback_->AddRef(); // Balanced in DoTruncateCachedMetadataComplete.
if (!entry_)
return OK;
if (net_log_.IsLoggingAllEvents())
net_log_.BeginEvent(NetLog::TYPE_HTTP_CACHE_WRITE_INFO, NULL);
return WriteToEntry(kMetadataIndex, 0, NULL, 0, cache_callback_);
}
int HttpCache::Transaction::DoTruncateCachedMetadataComplete(int result) {
if (net_log_.IsLoggingAllEvents() && entry_) {
net_log_.EndEventWithNetErrorCode(NetLog::TYPE_HTTP_CACHE_WRITE_INFO,
result);
}
// Balance the AddRef from DoTruncateCachedMetadata.
cache_callback_->Release();
// If this response is a redirect, then we can stop writing now. (We don't
// need to cache the response body of a redirect.)
if (response_.headers->IsRedirect(NULL))
DoneWritingToEntry(true);
next_state_ = STATE_PARTIAL_HEADERS_RECEIVED;
return OK;
}
int HttpCache::Transaction::DoPartialHeadersReceived() {
new_response_ = NULL;
if (entry_ && !partial_.get() &&
entry_->disk_entry->GetDataSize(kMetadataIndex))
next_state_ = STATE_CACHE_READ_METADATA;
if (!partial_.get())
return OK;
if (reading_) {
if (network_trans_.get()) {
next_state_ = STATE_NETWORK_READ;
} else {
next_state_ = STATE_CACHE_READ_DATA;
}
} else if (mode_ != NONE) {
// We are about to return the headers for a byte-range request to the user,
// so let's fix them.
partial_->FixResponseHeaders(response_.headers, true);
}
return OK;
}
int HttpCache::Transaction::DoCacheReadResponse() {
DCHECK(entry_);
next_state_ = STATE_CACHE_READ_RESPONSE_COMPLETE;
io_buf_len_ = entry_->disk_entry->GetDataSize(kResponseInfoIndex);
read_buf_ = new IOBuffer(io_buf_len_);
net_log_.BeginEvent(NetLog::TYPE_HTTP_CACHE_READ_INFO, NULL);
cache_callback_->AddRef(); // Balanced in DoCacheReadResponseComplete.
return entry_->disk_entry->ReadData(kResponseInfoIndex, 0, read_buf_,
io_buf_len_, cache_callback_);
}
int HttpCache::Transaction::DoCacheReadResponseComplete(int result) {
cache_callback_->Release(); // Balance the AddRef from DoCacheReadResponse.
net_log_.EndEventWithNetErrorCode(NetLog::TYPE_HTTP_CACHE_READ_INFO, result);
if (result != io_buf_len_ ||
!HttpCache::ParseResponseInfo(read_buf_->data(), io_buf_len_,
&response_, &truncated_)) {
DLOG(ERROR) << "ReadData failed: " << result;
return ERR_CACHE_READ_FAILURE;
}
next_state_ = STATE_NOTIFY_BEFORE_SEND_HEADERS;
return OK;
}
int HttpCache::Transaction::DoCacheWriteResponse() {
if (net_log_.IsLoggingAllEvents() && entry_)
net_log_.BeginEvent(NetLog::TYPE_HTTP_CACHE_WRITE_INFO, NULL);
return WriteResponseInfoToEntry(false);
}
int HttpCache::Transaction::DoCacheWriteTruncatedResponse() {
if (net_log_.IsLoggingAllEvents() && entry_)
net_log_.BeginEvent(NetLog::TYPE_HTTP_CACHE_WRITE_INFO, NULL);
return WriteResponseInfoToEntry(true);
}
int HttpCache::Transaction::DoCacheWriteResponseComplete(int result) {
next_state_ = target_state_;
target_state_ = STATE_NONE;
if (!entry_)
return OK;
if (net_log_.IsLoggingAllEvents()) {
net_log_.EndEventWithNetErrorCode(NetLog::TYPE_HTTP_CACHE_WRITE_INFO,
result);
}
// Balance the AddRef from WriteResponseInfoToEntry.
write_headers_callback_->Release();
if (result != io_buf_len_) {
DLOG(ERROR) << "failed to write response info to cache";
DoneWritingToEntry(false);
}
return OK;
}
int HttpCache::Transaction::DoCacheReadMetadata() {
DCHECK(entry_);
DCHECK(!response_.metadata);
next_state_ = STATE_CACHE_READ_METADATA_COMPLETE;
response_.metadata =
new IOBufferWithSize(entry_->disk_entry->GetDataSize(kMetadataIndex));
net_log_.BeginEvent(NetLog::TYPE_HTTP_CACHE_READ_INFO, NULL);
cache_callback_->AddRef(); // Balanced in DoCacheReadMetadataComplete.
return entry_->disk_entry->ReadData(kMetadataIndex, 0, response_.metadata,
response_.metadata->size(),
cache_callback_);
}
int HttpCache::Transaction::DoCacheReadMetadataComplete(int result) {
cache_callback_->Release(); // Balance the AddRef from DoCacheReadMetadata.
net_log_.EndEventWithNetErrorCode(NetLog::TYPE_HTTP_CACHE_READ_INFO, result);
if (result != response_.metadata->size()) {
DLOG(ERROR) << "ReadData failed: " << result;
return ERR_CACHE_READ_FAILURE;
}
return OK;
}
int HttpCache::Transaction::DoCacheQueryData() {
next_state_ = STATE_CACHE_QUERY_DATA_COMPLETE;
// Balanced in ValidateEntryHeadersAndContinue.
cache_callback_->AddRef();
return entry_->disk_entry->ReadyForSparseIO(cache_callback_);
}
int HttpCache::Transaction::DoCacheQueryDataComplete(int result) {
DCHECK_EQ(OK, result);
// Balance the AddRef from BeginPartialCacheValidation.
cache_callback_->Release();
if (!cache_)
return ERR_UNEXPECTED;
return ValidateEntryHeadersAndContinue(true);
}
int HttpCache::Transaction::DoCacheReadData() {
DCHECK(entry_);
next_state_ = STATE_CACHE_READ_DATA_COMPLETE;
cache_callback_->AddRef(); // Balanced in DoCacheReadDataComplete.
if (net_log_.IsLoggingAllEvents())
net_log_.BeginEvent(NetLog::TYPE_HTTP_CACHE_READ_DATA, NULL);
if (partial_.get()) {
return partial_->CacheRead(entry_->disk_entry, read_buf_, io_buf_len_,
cache_callback_);
}
return entry_->disk_entry->ReadData(kResponseContentIndex, read_offset_,
read_buf_, io_buf_len_, cache_callback_);
}
int HttpCache::Transaction::DoCacheReadDataComplete(int result) {
cache_callback_->Release(); // Balance the AddRef from DoCacheReadData.
if (net_log_.IsLoggingAllEvents()) {
net_log_.EndEventWithNetErrorCode(NetLog::TYPE_HTTP_CACHE_READ_DATA,
result);
}
if (!cache_)
return ERR_UNEXPECTED;
if (partial_.get())
return DoPartialCacheReadCompleted(result);
if (result > 0) {
read_offset_ += result;
} else if (result == 0) { // End of file.
cache_->DoneReadingFromEntry(entry_, this);
entry_ = NULL;
}
return result;
}
int HttpCache::Transaction::DoCacheWriteData(int num_bytes) {
next_state_ = STATE_CACHE_WRITE_DATA_COMPLETE;
write_len_ = num_bytes;
if (net_log_.IsLoggingAllEvents() && entry_)
net_log_.BeginEvent(NetLog::TYPE_HTTP_CACHE_WRITE_DATA, NULL);
cache_callback_->AddRef(); // Balanced in DoCacheWriteDataComplete.
return AppendResponseDataToEntry(read_buf_, num_bytes, cache_callback_);
}
int HttpCache::Transaction::DoCacheWriteDataComplete(int result) {
if (net_log_.IsLoggingAllEvents() && entry_) {
net_log_.EndEventWithNetErrorCode(NetLog::TYPE_HTTP_CACHE_WRITE_DATA,
result);
}
// Balance the AddRef from DoCacheWriteData.
cache_callback_->Release();
if (!cache_)
return ERR_UNEXPECTED;
if (result != write_len_) {
DLOG(ERROR) << "failed to write response data to cache";
DoneWritingToEntry(false);
// We want to ignore errors writing to disk and just keep reading from
// the network.
result = write_len_;
}
if (partial_.get()) {
// This may be the last request.
if (!(result == 0 && !truncated_ &&
(partial_->IsLastRange() || mode_ == WRITE)))
return DoPartialNetworkReadCompleted(result);
}
if (result == 0) // End of file.
DoneWritingToEntry(true);
return result;
}
//-----------------------------------------------------------------------------
void HttpCache::Transaction::SetRequest(const BoundNetLog& net_log,
const HttpRequestInfo* request) {
net_log_ = net_log;
request_ = request;
effective_load_flags_ = request_->load_flags;
switch (cache_->mode()) {
case NORMAL:
break;
case RECORD:
// When in record mode, we want to NEVER load from the cache.
// The reason for this is beacuse we save the Set-Cookie headers
// (intentionally). If we read from the cache, we replay them
// prematurely.
effective_load_flags_ |= LOAD_BYPASS_CACHE;
break;
case PLAYBACK:
// When in playback mode, we want to load exclusively from the cache.
effective_load_flags_ |= LOAD_ONLY_FROM_CACHE;
break;
case DISABLE:
effective_load_flags_ |= LOAD_DISABLE_CACHE;
break;
}
// 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;
if (request_->extra_headers.HasHeader(HttpRequestHeaders::kRange))
range_found = true;
for (size_t i = 0; i < ARRAYSIZE_UNSAFE(kSpecialHeaders); ++i) {
if (HeaderMatches(request_->extra_headers, kSpecialHeaders[i].search)) {
effective_load_flags_ |= kSpecialHeaders[i].load_flag;
break;
}
}
// Check for conditionalization headers which may correspond with a
// cache validation request.
for (size_t i = 0; i < arraysize(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;
break;
}
}
// 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)) {
partial_.reset(new PartialData);
if (partial_->Init(request_->extra_headers)) {
// We will be modifying the actual range requested to the server, so
// let's remove the header here.
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;
// When using the record/playback modes, we always use the cache
// and we never pass through.
if (cache_->mode() == RECORD || cache_->mode() == PLAYBACK)
return false;
if (effective_load_flags_ & LOAD_DISABLE_CACHE)
return true;
if (request_->method == "GET")
return false;
if (request_->method == "POST" &&
request_->upload_data && request_->upload_data->identifier())
return false;
// TODO(darin): add support for caching HEAD responses
return true;
}
int HttpCache::Transaction::BeginCacheRead() {
// We don't support any combination of LOAD_ONLY_FROM_CACHE and byte ranges.
if (response_.headers->response_code() == 206 || partial_.get()) {
NOTREACHED();
return ERR_CACHE_MISS;
}
// We don't have the whole resource.
if (truncated_)
return ERR_CACHE_MISS;
if (entry_->disk_entry->GetDataSize(kMetadataIndex))
next_state_ = STATE_CACHE_READ_METADATA;
return OK;
}
int HttpCache::Transaction::BeginCacheValidation() {
DCHECK(mode_ == READ_WRITE);
bool skip_validation = effective_load_flags_ & LOAD_PREFERRING_CACHE ||
!RequiresValidation();
if (truncated_)
skip_validation = !partial_->initial_validation();
if ((partial_.get() && !partial_->IsCurrentRangeCached()) || invalid_range_)
skip_validation = false;
if (skip_validation) {
if (partial_.get()) {
// We are going to return the saved response headers to the caller, so
// we may need to adjust them first.
next_state_ = STATE_PARTIAL_HEADERS_RECEIVED;
return OK;
}
cache_->ConvertWriterToReader(entry_);
mode_ = READ;
if (entry_ && entry_->disk_entry->GetDataSize(kMetadataIndex))
next_state_ = STATE_CACHE_READ_METADATA;
} 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. We'll switch to
// either READ or WRITE mode once we hear back from the server.
if (!ConditionalizeRequest()) {
DCHECK(!partial_.get());
DCHECK_NE(206, response_.headers->response_code());
mode_ = WRITE;
}
next_state_ = STATE_SEND_REQUEST;
}
return OK;
}
int HttpCache::Transaction::BeginPartialCacheValidation() {
DCHECK(mode_ == READ_WRITE);
if (response_.headers->response_code() != 206 && !partial_.get() &&
!truncated_)
return BeginCacheValidation();
bool byte_range_requested = partial_.get() != NULL;
if (byte_range_requested) {
next_state_ = STATE_CACHE_QUERY_DATA;
return OK;
}
// 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();
}
return ValidateEntryHeadersAndContinue(false);
}
// This should only be called once per request.
int HttpCache::Transaction::ValidateEntryHeadersAndContinue(
bool byte_range_requested) {
DCHECK(mode_ == READ_WRITE);
if (!partial_->UpdateFromStoredHeaders(response_.headers, entry_->disk_entry,
truncated_)) {
// The stored data cannot be used. Get rid of it and restart this request.
// We need to also reset the |truncated_| flag as a new entry is created.
DoomPartialEntry(!byte_range_requested);
mode_ = WRITE;
truncated_ = false;
next_state_ = STATE_INIT_ENTRY;
return OK;
}
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;
}
next_state_ = 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 < arraysize(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.
DoneWritingToEntry(true);
}
}
next_state_ = 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(
X509Certificate* client_cert) {
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(client_cert, &io_callback_);
if (rv != ERR_IO_PENDING)
return DoLoop(rv);
return rv;
}
int HttpCache::Transaction::RestartNetworkRequestWithAuth(
const string16& username,
const string16& password) {
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(username, password, &io_callback_);
if (rv != ERR_IO_PENDING)
return DoLoop(rv);
return rv;
}
bool 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
// In playback mode, nothing requires validation.
if (cache_->mode() == net::HttpCache::PLAYBACK)
return false;
if (effective_load_flags_ & LOAD_VALIDATE_CACHE)
return true;
if (response_.headers->RequiresValidation(
response_.request_time, response_.response_time, Time::Now()))
return true;
// Since Vary header computation is fairly expensive, we save it for last.
if (response_.vary_data.is_valid() &&
!response_.vary_data.MatchesRequest(*request_, *response_.headers))
return true;
return false;
}
bool HttpCache::Transaction::ConditionalizeRequest() {
DCHECK(response_.headers);
// This only makes sense for cached 200 or 206 responses.
if (response_.headers->response_code() != 200 &&
response_.headers->response_code() != 206)
return false;
// We should have handled this case before.
DCHECK(response_.headers->response_code() != 206 ||
response_.headers->HasStrongValidators());
// Just use the first available ETag and/or Last-Modified header value.
// TODO(darin): Or should we use the last?
std::string etag_value;
response_.headers->EnumerateHeader(NULL, "etag", &etag_value);
std::string last_modified_value;
response_.headers->EnumerateHeader(NULL, "last-modified",
&last_modified_value);
if (etag_value.empty() && last_modified_value.empty())
return false;
if (!partial_.get()) {
// Need to customize the request, so this forces us to allocate :(
custom_request_.reset(new HttpRequestInfo(*request_));
request_ = custom_request_.get();
}
DCHECK(custom_request_.get());
bool use_if_range = partial_.get() && !partial_->IsCurrentRangeCached() &&
!invalid_range_;
if (!etag_value.empty()) {
if (use_if_range) {
// We don't want to switch to WRITE mode if we don't have this block of a
// byte-range request because we may have other parts cached.
custom_request_->extra_headers.SetHeader(
HttpRequestHeaders::kIfRange, etag_value);
} else {
custom_request_->extra_headers.SetHeader(
HttpRequestHeaders::kIfNoneMatch, etag_value);
}
// For byte-range requests, make sure that we use only one way to validate
// the request.
if (partial_.get() && !partial_->IsCurrentRangeCached())
return true;
}
if (!last_modified_value.empty()) {
if (use_if_range) {
custom_request_->extra_headers.SetHeader(
HttpRequestHeaders::kIfRange, last_modified_value);
} else {
custom_request_->extra_headers.SetHeader(
HttpRequestHeaders::kIfModifiedSince, last_modified_value);
}
}
return true;
}
// We just received some headers from the server. We may have asked for a range,
// in which case partial_ has an object. This could be the first network request
// we make to fulfill the original request, or we may be already reading (from
// the net and / or the cache). If we are not expecting a certain response, we
// just bypass the cache for this request (but again, maybe we are reading), and
// delete partial_ (so we are not able to "fix" the headers that we return to
// the user). This results in either a weird response for the caller (we don't
// expect it after all), or maybe a range that was not exactly what it was asked
// for.
//
// If the server is simply telling us that the resource has changed, we delete
// the cached entry and restart the request as the caller intended (by returning
// false from this method). However, we may not be able to do that at any point,
// for instance if we already returned the headers to the user.
//
// WARNING: Whenever this code returns false, it has to make sure that the next
// time it is called it will return true so that we don't keep retrying the
// request.
bool HttpCache::Transaction::ValidatePartialResponse(bool* partial_content) {
const HttpResponseHeaders* headers = new_response_->headers;
int response_code = headers->response_code();
bool partial_response = (response_code == 206);
*partial_content = false;
if (!entry_)
return true;
if (invalid_range_) {
// We gave up trying to match this request with the stored data. If the
// server is ok with the request, delete the entry, otherwise just ignore
// this request
DCHECK(!reading_);
if (partial_response || response_code == 200) {
DoomPartialEntry(true);
mode_ = NONE;
} else {
if (response_code == 304)
FailRangeRequest();
IgnoreRangeRequest();
}
return true;
}
if (!partial_.get()) {
// We are not expecting 206 but we may have one.
if (partial_response)
IgnoreRangeRequest();
return true;
}
// TODO(rvargas): Do we need to consider other results here?.
bool failure = response_code == 200 || response_code == 416;
if (partial_->IsCurrentRangeCached()) {
// We asked for "If-None-Match: " so a 206 means a new object.
if (partial_response)
failure = true;
if (response_code == 304 && partial_->ResponseHeadersOK(headers))
return true;
} else {
// We asked for "If-Range: " so a 206 means just another range.
if (partial_response && partial_->ResponseHeadersOK(headers)) {
*partial_content = true;
return true;
}
// 304 is not expected here, but we'll spare the entry (unless it was
// truncated).
if (truncated_) {
if (!reading_ && response_code == 200) {
// The server is sending the whole resource, and we can save it.
DCHECK(!partial_->IsLastRange());
partial_.reset();
truncated_ = false;
return true;
}
failure = true;
}
}
if (failure) {
// We cannot truncate this entry, it has to be deleted.
DoomPartialEntry(false);
mode_ = NONE;
if (!reading_ && !partial_->IsLastRange()) {
// We'll attempt to issue another network request, this time without us
// messing up the headers.
partial_->RestoreHeaders(&custom_request_->extra_headers);
partial_.reset();
truncated_ = false;
return false;
}
LOG(WARNING) << "Failed to revalidate partial entry";
partial_.reset();
return true;
}
IgnoreRangeRequest();
return true;
}
void HttpCache::Transaction::IgnoreRangeRequest() {
// We have a problem. We may or may not be reading already (in which case we
// returned the headers), but we'll just pretend that this request is not
// using the cache and see what happens. Most likely this is the first
// response from the server (it's not changing its mind midway, right?).
if (mode_ & WRITE) {
DoneWritingToEntry(mode_ != WRITE);
} else if (mode_ & READ && entry_) {
cache_->DoneReadingFromEntry(entry_, this);
}
partial_.reset(NULL);
entry_ = NULL;
mode_ = NONE;
}
void HttpCache::Transaction::FailRangeRequest() {
response_ = *new_response_;
partial_->FixResponseHeaders(response_.headers, false);
}
int HttpCache::Transaction::ReadFromNetwork(IOBuffer* data, int data_len) {
read_buf_ = data;
io_buf_len_ = data_len;
next_state_ = STATE_NETWORK_READ;
return DoLoop(OK);
}
int HttpCache::Transaction::ReadFromEntry(IOBuffer* data, int data_len) {
read_buf_ = data;
io_buf_len_ = data_len;
next_state_ = STATE_CACHE_READ_DATA;
return DoLoop(OK);
}
int HttpCache::Transaction::WriteToEntry(int index, int offset,
IOBuffer* data, int data_len,
CompletionCallback* callback) {
if (!entry_)
return data_len;
int rv = 0;
if (!partial_.get() || !data_len) {
rv = entry_->disk_entry->WriteData(index, offset, data, data_len, callback,
true);
} else {
rv = partial_->CacheWrite(entry_->disk_entry, data, data_len, callback);
}
return rv;
}
int HttpCache::Transaction::WriteResponseInfoToEntry(bool truncated) {
next_state_ = STATE_CACHE_WRITE_RESPONSE_COMPLETE;
if (!entry_)
return OK;
// Do not cache no-store content (unless we are record mode). Do not cache
// content with cert errors either. This is to prevent not reporting net
// errors when loading a resource from the cache. When we load a page over
// HTTPS with a cert error we show an SSL blocking page. If the user clicks
// proceed we reload the resource ignoring the errors. The loaded resource
// is then cached. If that resource is subsequently loaded from the cache,
// no net error is reported (even though the cert status contains the actual
// errors) and no SSL blocking page is shown. An alternative would be to
// reverse-map the cert status to a net error and replay the net error.
if ((cache_->mode() != RECORD &&
response_.headers->HasHeaderValue("cache-control", "no-store")) ||
net::IsCertStatusError(response_.ssl_info.cert_status)) {
DoneWritingToEntry(false);
return OK;
}
// When writing headers, we normally only write the non-transient
// headers; when in record mode, record everything.
bool skip_transient_headers = (cache_->mode() != RECORD);
if (truncated) {
DCHECK_EQ(200, response_.headers->response_code());
}
scoped_refptr<PickledIOBuffer> data(new PickledIOBuffer());
response_.Persist(data->pickle(), skip_transient_headers, truncated);
data->Done();
// Balanced in DoCacheWriteResponseComplete. We may be running from the
// destructor of this object so cache_callback_ may be currently in use.
write_headers_callback_->AddRef();
io_buf_len_ = data->pickle()->size();
return entry_->disk_entry->WriteData(kResponseInfoIndex, 0, data, io_buf_len_,
write_headers_callback_, true);
}
int HttpCache::Transaction::AppendResponseDataToEntry(
IOBuffer* data, int data_len, CompletionCallback* callback) {
if (!entry_ || !data_len)
return data_len;
int current_size = entry_->disk_entry->GetDataSize(kResponseContentIndex);
return WriteToEntry(kResponseContentIndex, current_size, data, data_len,
callback);
}
void HttpCache::Transaction::DoneWritingToEntry(bool success) {
if (!entry_)
return;
if (cache_->mode() == RECORD)
DVLOG(1) << "Recorded: " << request_->method << request_->url
<< " status: " << response_.headers->response_code();
cache_->DoneWritingToEntry(entry_, success);
entry_ = NULL;
mode_ = NONE; // switch to 'pass through' mode
}
void HttpCache::Transaction::DoomPartialEntry(bool delete_object) {
DVLOG(2) << "DoomPartialEntry";
int rv = cache_->DoomEntry(cache_key_, NULL);
DCHECK_EQ(OK, rv);
cache_->DoneWithEntry(entry_, this, false);
entry_ = NULL;
is_sparse_ = false;
if (delete_object)
partial_.reset(NULL);
}
int HttpCache::Transaction::DoPartialNetworkReadCompleted(int result) {
partial_->OnNetworkReadCompleted(result);
if (result == 0) {
// We need to move on to the next range.
network_trans_.reset();
next_state_ = STATE_START_PARTIAL_CACHE_VALIDATION;
}
return result;
}
int HttpCache::Transaction::DoPartialCacheReadCompleted(int result) {
partial_->OnCacheReadCompleted(result);
if (result == 0 && mode_ == READ_WRITE) {
// We need to move on to the next range.
next_state_ = STATE_START_PARTIAL_CACHE_VALIDATION;
}
return result;
}
// Histogram data from the end of 2010 show the following distribution of
// response headers:
//
// Content-Length............... 87%
// Date......................... 98%
// Last-Modified................ 49%
// Etag......................... 19%
// Accept-Ranges: bytes......... 25%
// Accept-Ranges: none.......... 0.4%
// Strong Validator............. 50%
// Strong Validator + ranges.... 24%
// Strong Validator + CL........ 49%
//
bool HttpCache::Transaction::CanResume(bool has_data) {
// Double check that there is something worth keeping.
if (has_data && !entry_->disk_entry->GetDataSize(kResponseContentIndex))
return false;
if (request_->method != "GET")
return false;
if (response_.headers->GetContentLength() <= 0 ||
response_.headers->HasHeaderValue("Accept-Ranges", "none") ||
!response_.headers->HasStrongValidators())
return false;
return true;
}
void HttpCache::Transaction::OnIOComplete(int result) {
DoLoop(result);
}
} // namespace net