blob: b7cb185cd57d53785ba0d6e42408f0995fb9f64e [file] [log] [blame]
// Copyright (c) 2013 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/proxy/proxy_resolver_v8_tracing.h"
#include "base/bind.h"
#include "base/message_loop/message_loop_proxy.h"
#include "base/strings/stringprintf.h"
#include "base/synchronization/cancellation_flag.h"
#include "base/synchronization/waitable_event.h"
#include "base/threading/thread.h"
#include "base/threading/thread_restrictions.h"
#include "base/values.h"
#include "net/base/address_list.h"
#include "net/base/net_errors.h"
#include "net/base/net_log.h"
#include "net/dns/host_resolver.h"
#include "net/proxy/proxy_info.h"
#include "net/proxy/proxy_resolver_error_observer.h"
#include "net/proxy/proxy_resolver_v8.h"
// The intent of this class is explained in the design document:
// https://docs.google.com/a/chromium.org/document/d/16Ij5OcVnR3s0MH4Z5XkhI9VTPoMJdaBn9rKreAmGOdE/edit
//
// In a nutshell, PAC scripts are Javascript programs and may depend on
// network I/O, by calling functions like dnsResolve().
//
// This is problematic since functions such as dnsResolve() will block the
// Javascript execution until the DNS result is availble, thereby stalling the
// PAC thread, which hurts the ability to process parallel proxy resolves.
// An obvious solution is to simply start more PAC threads, however this scales
// poorly, which hurts the ability to process parallel proxy resolves.
//
// The solution in ProxyResolverV8Tracing is to model PAC scripts as being
// deterministic, and depending only on the inputted URL. When the script
// issues a dnsResolve() for a yet unresolved hostname, the Javascript
// execution is "aborted", and then re-started once the DNS result is
// known.
namespace net {
namespace {
// Upper bound on how many *unique* DNS resolves a PAC script is allowed
// to make. This is a failsafe both for scripts that do a ridiculous
// number of DNS resolves, as well as scripts which are misbehaving
// under the tracing optimization. It is not expected to hit this normally.
const size_t kMaxUniqueResolveDnsPerExec = 20;
// Approximate number of bytes to use for buffering alerts() and errors.
// This is a failsafe in case repeated executions of the script causes
// too much memory bloat. It is not expected for well behaved scripts to
// hit this. (In fact normal scripts should not even have alerts() or errors).
const size_t kMaxAlertsAndErrorsBytes = 2048;
// Returns event parameters for a PAC error message (line number + message).
base::Value* NetLogErrorCallback(int line_number,
const base::string16* message,
NetLog::LogLevel /* log_level */) {
base::DictionaryValue* dict = new base::DictionaryValue();
dict->SetInteger("line_number", line_number);
dict->SetString("message", *message);
return dict;
}
} // namespace
// The Job class is responsible for executing GetProxyForURL() and
// SetPacScript(), since both of these operations share similar code.
//
// The DNS for these operations can operate in either blocking or
// non-blocking mode. Blocking mode is used as a fallback when the PAC script
// seems to be misbehaving under the tracing optimization.
//
// Note that this class runs on both the origin thread and a worker
// thread. Most methods are expected to be used exclusively on one thread
// or the other.
//
// The lifetime of Jobs does not exceed that of the ProxyResolverV8Tracing that
// spawned it. Destruction might happen on either the origin thread or the
// worker thread.
class ProxyResolverV8Tracing::Job
: public base::RefCountedThreadSafe<ProxyResolverV8Tracing::Job>,
public ProxyResolverV8::JSBindings {
public:
// |parent| is non-owned. It is the ProxyResolverV8Tracing that spawned this
// Job, and must oulive it.
explicit Job(ProxyResolverV8Tracing* parent);
// Called from origin thread.
void StartSetPacScript(
const scoped_refptr<ProxyResolverScriptData>& script_data,
const CompletionCallback& callback);
// Called from origin thread.
void StartGetProxyForURL(const GURL& url,
ProxyInfo* results,
const BoundNetLog& net_log,
const CompletionCallback& callback);
// Called from origin thread.
void Cancel();
// Called from origin thread.
LoadState GetLoadState() const;
private:
typedef std::map<std::string, std::string> DnsCache;
friend class base::RefCountedThreadSafe<ProxyResolverV8Tracing::Job>;
enum Operation {
SET_PAC_SCRIPT,
GET_PROXY_FOR_URL,
};
struct AlertOrError {
bool is_alert;
int line_number;
base::string16 message;
};
virtual ~Job();
void CheckIsOnWorkerThread() const;
void CheckIsOnOriginThread() const;
void SetCallback(const CompletionCallback& callback);
void ReleaseCallback();
ProxyResolverV8* v8_resolver();
base::MessageLoop* worker_loop();
HostResolver* host_resolver();
ProxyResolverErrorObserver* error_observer();
NetLog* net_log();
// Invokes the user's callback.
void NotifyCaller(int result);
void NotifyCallerOnOriginLoop(int result);
void Start(Operation op, bool blocking_dns,
const CompletionCallback& callback);
void ExecuteBlocking();
void ExecuteNonBlocking();
int ExecuteProxyResolver();
// Implementation of ProxyResolverv8::JSBindings
virtual bool ResolveDns(const std::string& host,
ResolveDnsOperation op,
std::string* output,
bool* terminate) OVERRIDE;
virtual void Alert(const base::string16& message) OVERRIDE;
virtual void OnError(int line_number, const base::string16& error) OVERRIDE;
bool ResolveDnsBlocking(const std::string& host,
ResolveDnsOperation op,
std::string* output);
bool ResolveDnsNonBlocking(const std::string& host,
ResolveDnsOperation op,
std::string* output,
bool* terminate);
bool PostDnsOperationAndWait(const std::string& host,
ResolveDnsOperation op,
bool* completed_synchronously)
WARN_UNUSED_RESULT;
void DoDnsOperation();
void OnDnsOperationComplete(int result);
void ScheduleRestartWithBlockingDns();
bool GetDnsFromLocalCache(const std::string& host, ResolveDnsOperation op,
std::string* output, bool* return_value);
void SaveDnsToLocalCache(const std::string& host, ResolveDnsOperation op,
int net_error, const net::AddressList& addresses);
// Builds a RequestInfo to service the specified PAC DNS operation.
static HostResolver::RequestInfo MakeDnsRequestInfo(const std::string& host,
ResolveDnsOperation op);
// Makes a key for looking up |host, op| in |dns_cache_|. Strings are used for
// convenience, to avoid defining custom comparators.
static std::string MakeDnsCacheKey(const std::string& host,
ResolveDnsOperation op);
void HandleAlertOrError(bool is_alert, int line_number,
const base::string16& message);
void DispatchBufferedAlertsAndErrors();
void DispatchAlertOrError(bool is_alert, int line_number,
const base::string16& message);
void LogEventToCurrentRequestAndGlobally(
NetLog::EventType type,
const NetLog::ParametersCallback& parameters_callback);
// The thread which called into ProxyResolverV8Tracing, and on which the
// completion callback is expected to run.
scoped_refptr<base::MessageLoopProxy> origin_loop_;
// The ProxyResolverV8Tracing which spawned this Job.
// Initialized on origin thread and then accessed from both threads.
ProxyResolverV8Tracing* parent_;
// The callback to run (on the origin thread) when the Job finishes.
// Should only be accessed from origin thread.
CompletionCallback callback_;
// Flag to indicate whether the request has been cancelled.
base::CancellationFlag cancelled_;
// The operation that this Job is running.
// Initialized on origin thread and then accessed from both threads.
Operation operation_;
// The DNS mode for this Job.
// Initialized on origin thread, mutated on worker thread, and accessed
// by both the origin thread and worker thread.
bool blocking_dns_;
// Used to block the worker thread on a DNS operation taking place on the
// origin thread.
base::WaitableEvent event_;
// Map of DNS operations completed so far. Written into on the origin thread
// and read on the worker thread.
DnsCache dns_cache_;
// The job holds a reference to itself to ensure that it remains alive until
// either completion or cancellation.
scoped_refptr<Job> owned_self_reference_;
// -------------------------------------------------------
// State specific to SET_PAC_SCRIPT.
// -------------------------------------------------------
scoped_refptr<ProxyResolverScriptData> script_data_;
// -------------------------------------------------------
// State specific to GET_PROXY_FOR_URL.
// -------------------------------------------------------
ProxyInfo* user_results_; // Owned by caller, lives on origin thread.
GURL url_;
ProxyInfo results_;
BoundNetLog bound_net_log_;
// ---------------------------------------------------------------------------
// State for ExecuteNonBlocking()
// ---------------------------------------------------------------------------
// These variables are used exclusively on the worker thread and are only
// meaningful when executing inside of ExecuteNonBlocking().
// Whether this execution was abandoned due to a missing DNS dependency.
bool abandoned_;
// Number of calls made to ResolveDns() by this execution.
int num_dns_;
// Sequence of calls made to Alert() or OnError() by this execution.
std::vector<AlertOrError> alerts_and_errors_;
size_t alerts_and_errors_byte_cost_; // Approximate byte cost of the above.
// Number of calls made to ResolveDns() by the PREVIOUS execution.
int last_num_dns_;
// Whether the current execution needs to be restarted in blocking mode.
bool should_restart_with_blocking_dns_;
// ---------------------------------------------------------------------------
// State for pending DNS request.
// ---------------------------------------------------------------------------
// Handle to the outstanding request in the HostResolver, or NULL.
// This is mutated and used on the origin thread, however it may be read by
// the worker thread for some DCHECKS().
HostResolver::RequestHandle pending_dns_;
// Indicates if the outstanding DNS request completed synchronously. Written
// on the origin thread, and read by the worker thread.
bool pending_dns_completed_synchronously_;
// These are the inputs to DoDnsOperation(). Written on the worker thread,
// read by the origin thread.
std::string pending_dns_host_;
ResolveDnsOperation pending_dns_op_;
// This contains the resolved address list that DoDnsOperation() fills in.
// Used exclusively on the origin thread.
AddressList pending_dns_addresses_;
};
ProxyResolverV8Tracing::Job::Job(ProxyResolverV8Tracing* parent)
: origin_loop_(base::MessageLoopProxy::current()),
parent_(parent),
event_(true, false),
last_num_dns_(0),
pending_dns_(NULL) {
CheckIsOnOriginThread();
}
void ProxyResolverV8Tracing::Job::StartSetPacScript(
const scoped_refptr<ProxyResolverScriptData>& script_data,
const CompletionCallback& callback) {
CheckIsOnOriginThread();
script_data_ = script_data;
// Script initialization uses blocking DNS since there isn't any
// advantage to using non-blocking mode here. That is because the
// parent ProxyService can't submit any ProxyResolve requests until
// initialization has completed successfully!
Start(SET_PAC_SCRIPT, true /*blocking*/, callback);
}
void ProxyResolverV8Tracing::Job::StartGetProxyForURL(
const GURL& url,
ProxyInfo* results,
const BoundNetLog& net_log,
const CompletionCallback& callback) {
CheckIsOnOriginThread();
url_ = url;
user_results_ = results;
bound_net_log_ = net_log;
Start(GET_PROXY_FOR_URL, false /*non-blocking*/, callback);
}
void ProxyResolverV8Tracing::Job::Cancel() {
CheckIsOnOriginThread();
// There are several possibilities to consider for cancellation:
// (a) The job has been posted to the worker thread, however script execution
// has not yet started.
// (b) The script is executing on the worker thread.
// (c) The script is executing on the worker thread, however is blocked inside
// of dnsResolve() waiting for a response from the origin thread.
// (d) Nothing is running on the worker thread, however the host resolver has
// a pending DNS request which upon completion will restart the script
// execution.
// (e) The worker thread has a pending task to restart execution, which was
// posted after the DNS dependency was resolved and saved to local cache.
// (f) The script execution completed entirely, and posted a task to the
// origin thread to notify the caller.
//
// |cancelled_| is read on both the origin thread and worker thread. The
// code that runs on the worker thread is littered with checks on
// |cancelled_| to break out early.
cancelled_.Set();
ReleaseCallback();
if (pending_dns_) {
host_resolver()->CancelRequest(pending_dns_);
pending_dns_ = NULL;
}
// The worker thread might be blocked waiting for DNS.
event_.Signal();
owned_self_reference_ = NULL;
}
LoadState ProxyResolverV8Tracing::Job::GetLoadState() const {
CheckIsOnOriginThread();
if (pending_dns_)
return LOAD_STATE_RESOLVING_HOST_IN_PROXY_SCRIPT;
return LOAD_STATE_RESOLVING_PROXY_FOR_URL;
}
ProxyResolverV8Tracing::Job::~Job() {
DCHECK(!pending_dns_);
DCHECK(callback_.is_null());
}
void ProxyResolverV8Tracing::Job::CheckIsOnWorkerThread() const {
DCHECK_EQ(base::MessageLoop::current(), parent_->thread_->message_loop());
}
void ProxyResolverV8Tracing::Job::CheckIsOnOriginThread() const {
DCHECK(origin_loop_->BelongsToCurrentThread());
}
void ProxyResolverV8Tracing::Job::SetCallback(
const CompletionCallback& callback) {
CheckIsOnOriginThread();
DCHECK(callback_.is_null());
parent_->num_outstanding_callbacks_++;
callback_ = callback;
}
void ProxyResolverV8Tracing::Job::ReleaseCallback() {
CheckIsOnOriginThread();
DCHECK(!callback_.is_null());
CHECK_GT(parent_->num_outstanding_callbacks_, 0);
parent_->num_outstanding_callbacks_--;
callback_.Reset();
// For good measure, clear this other user-owned pointer.
user_results_ = NULL;
}
ProxyResolverV8* ProxyResolverV8Tracing::Job::v8_resolver() {
return parent_->v8_resolver_.get();
}
base::MessageLoop* ProxyResolverV8Tracing::Job::worker_loop() {
return parent_->thread_->message_loop();
}
HostResolver* ProxyResolverV8Tracing::Job::host_resolver() {
return parent_->host_resolver_;
}
ProxyResolverErrorObserver* ProxyResolverV8Tracing::Job::error_observer() {
return parent_->error_observer_.get();
}
NetLog* ProxyResolverV8Tracing::Job::net_log() {
return parent_->net_log_;
}
void ProxyResolverV8Tracing::Job::NotifyCaller(int result) {
CheckIsOnWorkerThread();
origin_loop_->PostTask(
FROM_HERE,
base::Bind(&Job::NotifyCallerOnOriginLoop, this, result));
}
void ProxyResolverV8Tracing::Job::NotifyCallerOnOriginLoop(int result) {
CheckIsOnOriginThread();
if (cancelled_.IsSet())
return;
DCHECK(!callback_.is_null());
DCHECK(!pending_dns_);
if (operation_ == GET_PROXY_FOR_URL) {
*user_results_ = results_;
}
// There is only ever 1 outstanding SET_PAC_SCRIPT job. It needs to be
// tracked to support cancellation.
if (operation_ == SET_PAC_SCRIPT) {
DCHECK_EQ(parent_->set_pac_script_job_.get(), this);
parent_->set_pac_script_job_ = NULL;
}
CompletionCallback callback = callback_;
ReleaseCallback();
callback.Run(result);
owned_self_reference_ = NULL;
}
void ProxyResolverV8Tracing::Job::Start(Operation op, bool blocking_dns,
const CompletionCallback& callback) {
CheckIsOnOriginThread();
operation_ = op;
blocking_dns_ = blocking_dns;
SetCallback(callback);
owned_self_reference_ = this;
worker_loop()->PostTask(FROM_HERE,
blocking_dns_ ? base::Bind(&Job::ExecuteBlocking, this) :
base::Bind(&Job::ExecuteNonBlocking, this));
}
void ProxyResolverV8Tracing::Job::ExecuteBlocking() {
CheckIsOnWorkerThread();
DCHECK(blocking_dns_);
if (cancelled_.IsSet())
return;
NotifyCaller(ExecuteProxyResolver());
}
void ProxyResolverV8Tracing::Job::ExecuteNonBlocking() {
CheckIsOnWorkerThread();
DCHECK(!blocking_dns_);
if (cancelled_.IsSet())
return;
// Reset state for the current execution.
abandoned_ = false;
num_dns_ = 0;
alerts_and_errors_.clear();
alerts_and_errors_byte_cost_ = 0;
should_restart_with_blocking_dns_ = false;
int result = ExecuteProxyResolver();
if (should_restart_with_blocking_dns_) {
DCHECK(!blocking_dns_);
DCHECK(abandoned_);
blocking_dns_ = true;
ExecuteBlocking();
return;
}
if (abandoned_)
return;
DispatchBufferedAlertsAndErrors();
NotifyCaller(result);
}
int ProxyResolverV8Tracing::Job::ExecuteProxyResolver() {
JSBindings* prev_bindings = v8_resolver()->js_bindings();
v8_resolver()->set_js_bindings(this);
int result = ERR_UNEXPECTED; // Initialized to silence warnings.
switch (operation_) {
case SET_PAC_SCRIPT:
result = v8_resolver()->SetPacScript(
script_data_, CompletionCallback());
break;
case GET_PROXY_FOR_URL:
result = v8_resolver()->GetProxyForURL(
url_,
// Important: Do not write directly into |user_results_|, since if the
// request were to be cancelled from the origin thread, must guarantee
// that |user_results_| is not accessed anymore.
&results_,
CompletionCallback(),
NULL,
bound_net_log_);
break;
}
v8_resolver()->set_js_bindings(prev_bindings);
return result;
}
bool ProxyResolverV8Tracing::Job::ResolveDns(const std::string& host,
ResolveDnsOperation op,
std::string* output,
bool* terminate) {
if (cancelled_.IsSet()) {
*terminate = true;
return false;
}
if ((op == DNS_RESOLVE || op == DNS_RESOLVE_EX) && host.empty()) {
// a DNS resolve with an empty hostname is considered an error.
return false;
}
return blocking_dns_ ?
ResolveDnsBlocking(host, op, output) :
ResolveDnsNonBlocking(host, op, output, terminate);
}
void ProxyResolverV8Tracing::Job::Alert(const base::string16& message) {
HandleAlertOrError(true, -1, message);
}
void ProxyResolverV8Tracing::Job::OnError(int line_number,
const base::string16& error) {
HandleAlertOrError(false, line_number, error);
}
bool ProxyResolverV8Tracing::Job::ResolveDnsBlocking(const std::string& host,
ResolveDnsOperation op,
std::string* output) {
CheckIsOnWorkerThread();
// Check if the DNS result for this host has already been cached.
bool rv;
if (GetDnsFromLocalCache(host, op, output, &rv)) {
// Yay, cache hit!
return rv;
}
if (dns_cache_.size() >= kMaxUniqueResolveDnsPerExec) {
// Safety net for scripts with unexpectedly many DNS calls.
// We will continue running to completion, but will fail every
// subsequent DNS request.
return false;
}
if (!PostDnsOperationAndWait(host, op, NULL))
return false; // Was cancelled.
CHECK(GetDnsFromLocalCache(host, op, output, &rv));
return rv;
}
bool ProxyResolverV8Tracing::Job::ResolveDnsNonBlocking(const std::string& host,
ResolveDnsOperation op,
std::string* output,
bool* terminate) {
CheckIsOnWorkerThread();
if (abandoned_) {
// If this execution was already abandoned can fail right away. Only 1 DNS
// dependency will be traced at a time (for more predictable outcomes).
return false;
}
num_dns_ += 1;
// Check if the DNS result for this host has already been cached.
bool rv;
if (GetDnsFromLocalCache(host, op, output, &rv)) {
// Yay, cache hit!
return rv;
}
if (num_dns_ <= last_num_dns_) {
// The sequence of DNS operations is different from last time!
ScheduleRestartWithBlockingDns();
*terminate = true;
return false;
}
if (dns_cache_.size() >= kMaxUniqueResolveDnsPerExec) {
// Safety net for scripts with unexpectedly many DNS calls.
return false;
}
DCHECK(!should_restart_with_blocking_dns_);
bool completed_synchronously;
if (!PostDnsOperationAndWait(host, op, &completed_synchronously))
return false; // Was cancelled.
if (completed_synchronously) {
CHECK(GetDnsFromLocalCache(host, op, output, &rv));
return rv;
}
// Otherwise if the result was not in the cache, then a DNS request has
// been started. Abandon this invocation of FindProxyForURL(), it will be
// restarted once the DNS request completes.
abandoned_ = true;
*terminate = true;
last_num_dns_ = num_dns_;
return false;
}
bool ProxyResolverV8Tracing::Job::PostDnsOperationAndWait(
const std::string& host, ResolveDnsOperation op,
bool* completed_synchronously) {
// Post the DNS request to the origin thread.
DCHECK(!pending_dns_);
pending_dns_host_ = host;
pending_dns_op_ = op;
origin_loop_->PostTask(FROM_HERE, base::Bind(&Job::DoDnsOperation, this));
event_.Wait();
event_.Reset();
if (cancelled_.IsSet())
return false;
if (completed_synchronously)
*completed_synchronously = pending_dns_completed_synchronously_;
return true;
}
void ProxyResolverV8Tracing::Job::DoDnsOperation() {
CheckIsOnOriginThread();
DCHECK(!pending_dns_);
if (cancelled_.IsSet())
return;
HostResolver::RequestHandle dns_request = NULL;
int result = host_resolver()->Resolve(
MakeDnsRequestInfo(pending_dns_host_, pending_dns_op_),
DEFAULT_PRIORITY,
&pending_dns_addresses_,
base::Bind(&Job::OnDnsOperationComplete, this),
&dns_request,
bound_net_log_);
pending_dns_completed_synchronously_ = result != ERR_IO_PENDING;
// Check if the request was cancelled as a side-effect of calling into the
// HostResolver. This isn't the ordinary execution flow, however it is
// exercised by unit-tests.
if (cancelled_.IsSet()) {
if (!pending_dns_completed_synchronously_)
host_resolver()->CancelRequest(dns_request);
return;
}
if (pending_dns_completed_synchronously_) {
OnDnsOperationComplete(result);
} else {
DCHECK(dns_request);
pending_dns_ = dns_request;
// OnDnsOperationComplete() will be called by host resolver on completion.
}
if (!blocking_dns_) {
// The worker thread always blocks waiting to see if the result can be
// serviced from cache before restarting.
event_.Signal();
}
}
void ProxyResolverV8Tracing::Job::OnDnsOperationComplete(int result) {
CheckIsOnOriginThread();
DCHECK(!cancelled_.IsSet());
DCHECK(pending_dns_completed_synchronously_ == (pending_dns_ == NULL));
SaveDnsToLocalCache(pending_dns_host_, pending_dns_op_, result,
pending_dns_addresses_);
pending_dns_ = NULL;
if (blocking_dns_) {
event_.Signal();
return;
}
if (!blocking_dns_ && !pending_dns_completed_synchronously_) {
// Restart. This time it should make more progress due to having
// cached items.
worker_loop()->PostTask(FROM_HERE,
base::Bind(&Job::ExecuteNonBlocking, this));
}
}
void ProxyResolverV8Tracing::Job::ScheduleRestartWithBlockingDns() {
CheckIsOnWorkerThread();
DCHECK(!should_restart_with_blocking_dns_);
DCHECK(!abandoned_);
DCHECK(!blocking_dns_);
abandoned_ = true;
// The restart will happen after ExecuteNonBlocking() finishes.
should_restart_with_blocking_dns_ = true;
}
bool ProxyResolverV8Tracing::Job::GetDnsFromLocalCache(
const std::string& host,
ResolveDnsOperation op,
std::string* output,
bool* return_value) {
CheckIsOnWorkerThread();
DnsCache::const_iterator it = dns_cache_.find(MakeDnsCacheKey(host, op));
if (it == dns_cache_.end())
return false;
*output = it->second;
*return_value = !it->second.empty();
return true;
}
void ProxyResolverV8Tracing::Job::SaveDnsToLocalCache(
const std::string& host,
ResolveDnsOperation op,
int net_error,
const net::AddressList& addresses) {
CheckIsOnOriginThread();
// Serialize the result into a string to save to the cache.
std::string cache_value;
if (net_error != OK) {
cache_value = std::string();
} else if (op == DNS_RESOLVE || op == MY_IP_ADDRESS) {
// dnsResolve() and myIpAddress() are expected to return a single IP
// address.
cache_value = addresses.front().ToStringWithoutPort();
} else {
// The *Ex versions are expected to return a semi-colon separated list.
for (AddressList::const_iterator iter = addresses.begin();
iter != addresses.end(); ++iter) {
if (!cache_value.empty())
cache_value += ";";
cache_value += iter->ToStringWithoutPort();
}
}
dns_cache_[MakeDnsCacheKey(host, op)] = cache_value;
}
// static
HostResolver::RequestInfo ProxyResolverV8Tracing::Job::MakeDnsRequestInfo(
const std::string& host, ResolveDnsOperation op) {
HostPortPair host_port = HostPortPair(host, 80);
if (op == MY_IP_ADDRESS || op == MY_IP_ADDRESS_EX) {
host_port.set_host(GetHostName());
}
HostResolver::RequestInfo info(host_port);
// Flag myIpAddress requests.
if (op == MY_IP_ADDRESS || op == MY_IP_ADDRESS_EX) {
// TODO: Provide a RequestInfo construction mechanism that does not
// require a hostname and sets is_my_ip_address to true instead of this.
info.set_is_my_ip_address(true);
}
// The non-ex flavors are limited to IPv4 results.
if (op == MY_IP_ADDRESS || op == DNS_RESOLVE) {
info.set_address_family(ADDRESS_FAMILY_IPV4);
}
return info;
}
std::string ProxyResolverV8Tracing::Job::MakeDnsCacheKey(
const std::string& host, ResolveDnsOperation op) {
return base::StringPrintf("%d:%s", op, host.c_str());
}
void ProxyResolverV8Tracing::Job::HandleAlertOrError(
bool is_alert,
int line_number,
const base::string16& message) {
CheckIsOnWorkerThread();
if (cancelled_.IsSet())
return;
if (blocking_dns_) {
// In blocking DNS mode the events can be dispatched immediately.
DispatchAlertOrError(is_alert, line_number, message);
return;
}
// Otherwise in nonblocking mode, buffer all the messages until
// the end.
if (abandoned_)
return;
alerts_and_errors_byte_cost_ += sizeof(AlertOrError) + message.size() * 2;
// If there have been lots of messages, enqueing could be expensive on
// memory. Consider a script which does megabytes worth of alerts().
// Avoid this by falling back to blocking mode.
if (alerts_and_errors_byte_cost_ > kMaxAlertsAndErrorsBytes) {
ScheduleRestartWithBlockingDns();
return;
}
AlertOrError entry = {is_alert, line_number, message};
alerts_and_errors_.push_back(entry);
}
void ProxyResolverV8Tracing::Job::DispatchBufferedAlertsAndErrors() {
CheckIsOnWorkerThread();
DCHECK(!blocking_dns_);
DCHECK(!abandoned_);
for (size_t i = 0; i < alerts_and_errors_.size(); ++i) {
const AlertOrError& x = alerts_and_errors_[i];
DispatchAlertOrError(x.is_alert, x.line_number, x.message);
}
}
void ProxyResolverV8Tracing::Job::DispatchAlertOrError(
bool is_alert, int line_number, const base::string16& message) {
CheckIsOnWorkerThread();
// Note that the handling of cancellation is racy with regard to
// alerts/errors. The request might get cancelled shortly after this
// check! (There is no lock being held to guarantee otherwise).
//
// If this happens, then some information will get written to the NetLog
// needlessly, however the NetLog will still be alive so it shouldn't cause
// problems.
if (cancelled_.IsSet())
return;
if (is_alert) {
// -------------------
// alert
// -------------------
VLOG(1) << "PAC-alert: " << message;
// Send to the NetLog.
LogEventToCurrentRequestAndGlobally(
NetLog::TYPE_PAC_JAVASCRIPT_ALERT,
NetLog::StringCallback("message", &message));
} else {
// -------------------
// error
// -------------------
if (line_number == -1)
VLOG(1) << "PAC-error: " << message;
else
VLOG(1) << "PAC-error: " << "line: " << line_number << ": " << message;
// Send the error to the NetLog.
LogEventToCurrentRequestAndGlobally(
NetLog::TYPE_PAC_JAVASCRIPT_ERROR,
base::Bind(&NetLogErrorCallback, line_number, &message));
if (error_observer())
error_observer()->OnPACScriptError(line_number, message);
}
}
void ProxyResolverV8Tracing::Job::LogEventToCurrentRequestAndGlobally(
NetLog::EventType type,
const NetLog::ParametersCallback& parameters_callback) {
CheckIsOnWorkerThread();
bound_net_log_.AddEvent(type, parameters_callback);
// Emit to the global NetLog event stream.
if (net_log())
net_log()->AddGlobalEntry(type, parameters_callback);
}
ProxyResolverV8Tracing::ProxyResolverV8Tracing(
HostResolver* host_resolver,
ProxyResolverErrorObserver* error_observer,
NetLog* net_log)
: ProxyResolver(true /*expects_pac_bytes*/),
host_resolver_(host_resolver),
error_observer_(error_observer),
net_log_(net_log),
num_outstanding_callbacks_(0) {
DCHECK(host_resolver);
// Start up the thread.
thread_.reset(new base::Thread("Proxy resolver"));
base::Thread::Options options;
options.timer_slack = base::TIMER_SLACK_MAXIMUM;
CHECK(thread_->StartWithOptions(options));
v8_resolver_.reset(new ProxyResolverV8);
}
ProxyResolverV8Tracing::~ProxyResolverV8Tracing() {
// Note, all requests should have been cancelled.
CHECK(!set_pac_script_job_.get());
CHECK_EQ(0, num_outstanding_callbacks_);
// Join the worker thread. See http://crbug.com/69710. Note that we call
// Stop() here instead of simply clearing thread_ since there may be pending
// callbacks on the worker thread which want to dereference thread_.
base::ThreadRestrictions::ScopedAllowIO allow_io;
thread_->Stop();
}
int ProxyResolverV8Tracing::GetProxyForURL(const GURL& url,
ProxyInfo* results,
const CompletionCallback& callback,
RequestHandle* request,
const BoundNetLog& net_log) {
DCHECK(CalledOnValidThread());
DCHECK(!callback.is_null());
DCHECK(!set_pac_script_job_.get());
scoped_refptr<Job> job = new Job(this);
if (request)
*request = job.get();
job->StartGetProxyForURL(url, results, net_log, callback);
return ERR_IO_PENDING;
}
void ProxyResolverV8Tracing::CancelRequest(RequestHandle request) {
Job* job = reinterpret_cast<Job*>(request);
job->Cancel();
}
LoadState ProxyResolverV8Tracing::GetLoadState(RequestHandle request) const {
Job* job = reinterpret_cast<Job*>(request);
return job->GetLoadState();
}
void ProxyResolverV8Tracing::CancelSetPacScript() {
DCHECK(set_pac_script_job_.get());
set_pac_script_job_->Cancel();
set_pac_script_job_ = NULL;
}
int ProxyResolverV8Tracing::SetPacScript(
const scoped_refptr<ProxyResolverScriptData>& script_data,
const CompletionCallback& callback) {
DCHECK(CalledOnValidThread());
DCHECK(!callback.is_null());
// Note that there should not be any outstanding (non-cancelled) Jobs when
// setting the PAC script (ProxyService should guarantee this). If there are,
// then they might complete in strange ways after the new script is set.
DCHECK(!set_pac_script_job_.get());
CHECK_EQ(0, num_outstanding_callbacks_);
set_pac_script_job_ = new Job(this);
set_pac_script_job_->StartSetPacScript(script_data, callback);
return ERR_IO_PENDING;
}
} // namespace net