Upstream Android proxy config service.

net/proxy/proxy_config_service_android.cc

+// 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/proxy/proxy_config_service_android.h"
+
+#include <sys/system_properties.h>
+
+#include "base/android/jni_android.h"
+#include "base/android/jni_string.h"
+#include "base/android/scoped_java_ref.h"
+#include "base/basictypes.h"
+#include "base/bind.h"
+#include "base/compiler_specific.h"
+#include "base/location.h"
+#include "base/logging.h"
+#include "base/memory/ref_counted.h"
+#include "base/observer_list.h"
+#include "base/single_thread_task_runner.h"
+#include "base/string_tokenizer.h"
+#include "base/string_util.h"
+#include "googleurl/src/url_parse.h"
+#include "jni/proxy_change_listener_jni.h"
+#include "net/base/host_port_pair.h"
+#include "net/proxy/proxy_config.h"
+
+using base::android::AttachCurrentThread;
+using base::android::ConvertUTF8ToJavaString;
+using base::android::ConvertJavaStringToUTF8;
+using base::android::CheckException;
+using base::android::ClearException;
+using base::android::GetMethodID;
+
+namespace net {
+
+namespace {
+
+// Returns whether the provided string was successfully converted to a port.
+bool ConvertStringToPort(const std::string& port, int* output) {
+  url_parse::Component component(0, port.size());
+  int result = url_parse::ParsePort(port.c_str(), component);
+  if (result == url_parse::PORT_INVALID ||
+      result == url_parse::PORT_UNSPECIFIED)
+    return false;
+  *output = result;
+  return true;
+}
+
+ProxyServer ConstructProxyServer(ProxyServer::Scheme scheme,
+                                 const std::string& proxy_host,
+                                 const std::string& proxy_port) {
+  DCHECK(!proxy_host.empty());
+  int port_as_int = 0;
+  if (proxy_port.empty())
+    port_as_int = ProxyServer::GetDefaultPortForScheme(scheme);
+  else if (!ConvertStringToPort(proxy_port, &port_as_int))
+    return ProxyServer();
+  DCHECK(port_as_int > 0);
+  return ProxyServer::FromURI(

[Ryan Sleevi, 2012/05/19 01:26:31]

use the constructor

return ProxyServer(scheme, HostPortPair(proxy_host, ...));

[Philippe, 2012/05/22 15:23:05]

Done.

+      HostPortPair(proxy_host, static_cast<uint>(port_as_int)).ToString(),

[Ryan Sleevi, 2012/05/19 01:26:31]

uint16

[Philippe, 2012/05/22 15:23:05]

Done.

+      scheme);
+}
+
+ProxyServer LookupProxy(
+    const std::string& prefix,
+    ProxyConfigServiceAndroid::Delegate* delegate,
+    ProxyServer::Scheme scheme) {
+  DCHECK(!prefix.empty());
+  std::string proxy_host = delegate->GetProperty(prefix + ".proxyHost");
+  if (!proxy_host.empty()) {
+    std::string proxy_port = delegate->GetProperty(prefix + ".proxyPort");
+    return ConstructProxyServer(scheme, proxy_host, proxy_port);
+  }
+  // Fall back to default proxy, if any.
+  proxy_host = delegate->GetProperty("proxyHost");
+  if (!proxy_host.empty()) {
+    std::string proxy_port = delegate->GetProperty("proxyPort");
+    return ConstructProxyServer(scheme, proxy_host, proxy_port);
+  }
+  return ProxyServer();
+}
+
+ProxyServer LookupSocksProxy(
+    ProxyConfigServiceAndroid::Delegate* delegate) {
+  std::string proxy_host = delegate->GetProperty("socksProxyHost");
+  if (!proxy_host.empty()) {
+    std::string proxy_port = delegate->GetProperty("socksProxyPort");
+    return ConstructProxyServer(ProxyServer::SCHEME_SOCKS5, proxy_host,
+                                proxy_port);
+  }
+  return ProxyServer();
+}
+
+void AddBypassRules(
+    const std::string& scheme,
+    ProxyConfigServiceAndroid::Delegate* delegate,
+    ProxyBypassRules* bypass_rules) {
+  // The format of a hostname pattern is a list of hostnames that are separated
+  // by | and that use * as a wildcard. For example, setting the
+  // http.nonProxyHosts property to *.android.com|*.kernel.org will cause
+  // requests to http://developer.android.com to be made without a proxy.
+  std::string non_proxy_hosts =
+      delegate->GetProperty(scheme + ".nonProxyHosts");
+  if (non_proxy_hosts.empty())
+    return;
+  StringTokenizer tokenizer(non_proxy_hosts, "|");
+  while (tokenizer.GetNext()) {
+    std::string token = tokenizer.token();
+    std::string pattern;
+    TrimWhitespaceASCII(token, TRIM_ALL, &pattern);
+    if (pattern.empty())
+      continue;
+    // '?' is not one of the specified pattern characters above.
+    DCHECK_EQ(std::string::npos, pattern.find('?'));
+    bypass_rules->AddRuleForHostname(scheme, pattern, -1);
+  }
+}
+
+// returns true if a valid proxy was found.
+bool GetProxyRules(
+    ProxyConfigServiceAndroid::Delegate* delegate,
+    ProxyConfig::ProxyRules* rules) {
+  // See libcore/luni/src/main/java/java/net/ProxySelectorImpl.java for the
+  // equivalent Android implementation.
+  rules->type = ProxyConfig::ProxyRules::TYPE_PROXY_PER_SCHEME;
+  rules->proxy_for_http = LookupProxy("http", delegate,
+                                      ProxyServer::SCHEME_HTTP);
+  rules->proxy_for_https = LookupProxy("https", delegate,
+                                       ProxyServer::SCHEME_HTTPS);
+  rules->proxy_for_ftp = LookupProxy("ftp", delegate, ProxyServer::SCHEME_HTTP);
+  rules->fallback_proxy = LookupSocksProxy(delegate);
+  rules->bypass_rules.Clear();
+  AddBypassRules("ftp", delegate, &rules->bypass_rules);
+  AddBypassRules("http", delegate, &rules->bypass_rules);
+  AddBypassRules("https", delegate, &rules->bypass_rules);
+  return rules->proxy_for_http.is_valid() ||
+      rules->proxy_for_https.is_valid() ||
+      rules->proxy_for_ftp.is_valid() ||
+      rules->fallback_proxy.is_valid();
+};
+
+void GetLatestProxyConfigInternal(
+    ProxyConfigServiceAndroid::Delegate* delegate,
+    ProxyConfig* config) {
+  if (!GetProxyRules(delegate, &config->proxy_rules()))
+    *config = ProxyConfig::CreateDirect();
+}
+
+// This class implements the link to Android's proxy broadcast mechanism.
+class DelegateImpl : public ProxyConfigServiceAndroid::Delegate {
+ public:
+  virtual void Start(ProxyConfigServiceAndroid* service) OVERRIDE {
+    JNIEnv* env = AttachCurrentThread();
+    if (java_proxy_change_listener_android_.is_null()) {
+      java_proxy_change_listener_android_.Reset(
+          Java_ProxyChangeListener_create(
+              env, base::android::GetApplicationContext()));
+      CHECK(!java_proxy_change_listener_android_.is_null());
+    }
+    Java_ProxyChangeListener_start(
+        env,
+        java_proxy_change_listener_android_.obj(),
+        reinterpret_cast<jint>(service));
+  }
+
+  virtual void Stop() OVERRIDE {
+    // The java object will be NULL if Stop() was already called (e.g. after a
+    // Start()), or if Start() was never called. Stop() is called from the
+    // destructor of ProxyConfigServiceAndroid.
+    if (java_proxy_change_listener_android_.is_null())
+      return;
+    JNIEnv* env = AttachCurrentThread();
+    Java_ProxyChangeListener_stop(env,
+                                  java_proxy_change_listener_android_.obj());
+  }
+
+  virtual std::string GetProperty(const std::string& property) OVERRIDE {
+    // Use Java System.getProperty to get configuration information.
+    // TODO(pliard): Conversion to/from UTF8 ok here?
+    JNIEnv* env = AttachCurrentThread();
+    ScopedJavaLocalRef<jstring> str = ConvertUTF8ToJavaString(env, property);
+    ScopedJavaLocalRef<jstring> result =
+        Java_ProxyChangeListener_getProperty(env, str.obj());
+    return result.is_null()
+        ? std::string()

[Ryan Sleevi, 2012/05/19 01:26:31]

the ? should be on the previous line

See http://www.chromium.org/developers/coding-style "When expressions are
wrapped"

[Philippe, 2012/05/22 15:23:05]

Done.

+        : ConvertJavaStringToUTF8(env, result.obj());
+  }
+
+ private:
+  base::android::ScopedJavaGlobalRef<jobject>
+      java_proxy_change_listener_android_;
+};
+
+}  // namespace
+
+class ProxyConfigServiceAndroid::SharedState
+    : public base::RefCountedThreadSafe<SharedState> {
+ public:
+  explicit SharedState(Delegate* delegate) : delegate_(delegate) {
+    DCHECK(delegate);
+  }
+
+  // Non-reassignable pointer thus safely readable by any thread.
+  const scoped_ptr<Delegate> delegate_;
+  // Note that this is only accessed from the observer thread.
+  ObserverList<Observer> observers_;
+
+ private:
+  friend class base::RefCountedThreadSafe<SharedState>;
+  ~SharedState() {}
+
+  DISALLOW_COPY_AND_ASSIGN(SharedState);
+};
+
+ProxyConfigServiceAndroid::ProxyConfigServiceAndroid(
+    base::SingleThreadTaskRunner* observer_runner)
+    : shared_state_(new SharedState(new DelegateImpl())),
+      observer_runner_(observer_runner) {
+  DCHECK(observer_runner_.get());
+}
+
+ProxyConfigServiceAndroid::~ProxyConfigServiceAndroid() {
+  shared_state_->delegate_->Stop();
+}
+
+// static
+bool ProxyConfigServiceAndroid::Register(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+void ProxyConfigServiceAndroid::AddObserver(Observer* observer) {
+  DCHECK(OnObserverThread());
+  if (shared_state_->observers_.size() == 0)
+    shared_state_->delegate_->Start(this);
+  // Note that any callbacks from the delegate will result in a scheduled task
+  // on this same thread, so there is no race between delegate_->Start() and
+  // AddObserver().
+  shared_state_->observers_.AddObserver(observer);
+}
+
+void ProxyConfigServiceAndroid::RemoveObserver(Observer* observer) {
+  DCHECK(OnObserverThread());
+  shared_state_->observers_.RemoveObserver(observer);
+  if (shared_state_->observers_.size() == 0)
+    shared_state_->delegate_->Stop();
+}
+
+ProxyConfigService::ConfigAvailability
+ProxyConfigServiceAndroid::GetLatestProxyConfig(ProxyConfig* config) {
+  if (!config)
+    return ProxyConfigService::CONFIG_UNSET;
+  GetLatestProxyConfigInternal(shared_state_->delegate_.get(), config);
+  return ProxyConfigService::CONFIG_VALID;
+}
+
+void ProxyConfigServiceAndroid::ProxySettingsChangedInternal() {
+  observer_runner_->PostTask(
+      FROM_HERE, base::Bind(&ProxySettingsChangedCallback, shared_state_));
+}
+
+ProxyConfigServiceAndroid::ProxyConfigServiceAndroid(
+    base::SingleThreadTaskRunner* observer_runner,
+    ProxyConfigServiceAndroid::Delegate* delegate)
+    : shared_state_(new SharedState(delegate)),
+      observer_runner_(observer_runner) {
+  DCHECK(observer_runner_.get());
+}
+
+// static
+void ProxyConfigServiceAndroid::ProxySettingsChangedCallback(
+    const scoped_refptr<SharedState>& callback_state) {
+  // Allow another task to be scheduled (before running observers).
+  ProxyConfig config;
+  GetLatestProxyConfigInternal(callback_state->delegate_.get(), &config);
+  FOR_EACH_OBSERVER(Observer, callback_state->observers_,
+                    OnProxyConfigChanged(config,
+                                         ProxyConfigService::CONFIG_VALID));

[Ryan Sleevi, 2012/05/19 01:26:31]

I don't believe the threading is correct here.

The observers should only have OnProxyConfigChanged called on the IO thread (see
for example
http://src.chromium.org/viewvc/chrome/trunk/src/net/proxy/proxy_config_servic...
- OnProxyConfigChanged should be called on the IO thread)

You call this thread on the observer_runner_ (see line 257), which suggests that
|observer_runner_| should be the IO thread.

However, you call GetLatestProxyConfigInternal on this thread (line 274), which
calls GetProxyRules (line 145), which calls LookupProxy (line 126), which calls
GetProperty (line 69), which attaches JNI to the thread (line 180), which should
only be done on the UI thread.

If you look in the ProxyConfigServiceLinux (
http://src.chromium.org/viewvc/chrome/trunk/src/net/proxy/proxy_config_servic...
), you'll see the SettingsGetter, which takes the /ui/ and /file/ loops.

I believe what you want is:
1) Receive a STTR for the UI thread and the IO thread.
2) Post a task to the UI thread to do JNI registration & setup, and start
observing (on the UI thread)
3) When the UI thread callback is called, fetch all of the proxy settings
4) Post a task to the IO thread to wake it
5) Have the IO thread receive the settings, (optionally compare with existing),
then notify observers (on the IO thread)

Since you also need to do some de-registration, when the object goes out of
scope (on the IO thread), post a task to the UI thread to stop monitoring to the
SharedState/Delegate, then continue destruction. Eventually the UI thread will
notice this, deregister, and then destroy the refcounted shared-state on the UI
thread.

If you need to ensure that from point of destruction (on the IO thread) no
further messages are delivered on the IO thread, use a WeakPtr for the
ProxyConfigServiceAndroid. Any tasks posted to the IO thread that run after the
PCSA has gone out of scope will then not run, because on PCSA destruction, it
invalidated all weak ptrs.

[Philippe, 2012/05/22 15:23:05]

Indeed.

Now I fetch the latest proxy config in ProxySettingsChangedInternal() running on
the JNI thread (UI thread). The function also stores this config (which
unfortunately requires a new Lock) so that clients can quickly and safely fetch
it back later through GetLatestProxyConfig().

Regarding WeakPtr, we considered that with John a few weeks ago but it seems
that we would be exposed to threading issues. From weak_ptr.h's top-level
comment, a WeakPtr can't be constructed on a thread and then dereferenced on
another one. That is unfortunate.

+}
+
+bool ProxyConfigServiceAndroid::OnObserverThread() const {
+  return observer_runner_->BelongsToCurrentThread();
+}
+
+} // namespace net