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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "chromeos/dbus/introspectable_client.h"
      6 
      7 #include <string>
      8 #include <vector>
      9 
     10 #include "base/bind.h"
     11 #include "base/logging.h"
     12 #include "dbus/bus.h"
     13 #include "dbus/message.h"
     14 #include "dbus/object_path.h"
     15 #include "dbus/object_proxy.h"
     16 #include "third_party/libxml/chromium/libxml_utils.h"
     17 
     18 namespace {
     19 
     20 // D-Bus specification constants.
     21 const char kIntrospectableInterface[] = "org.freedesktop.DBus.Introspectable";
     22 const char kIntrospect[] = "Introspect";
     23 
     24 // String constants used for parsing D-Bus Introspection XML data.
     25 const char kInterfaceNode[] = "interface";
     26 const char kInterfaceNameAttribute[] = "name";
     27 
     28 }  // namespace
     29 
     30 namespace chromeos {
     31 
     32 // The IntrospectableClient implementation used in production.
     33 class IntrospectableClientImpl : public IntrospectableClient {
     34  public:
     35   explicit IntrospectableClientImpl(dbus::Bus* bus)
     36       : bus_(bus),
     37         weak_ptr_factory_(this) {
     38   }
     39 
     40   virtual ~IntrospectableClientImpl() {
     41   }
     42 
     43   // IntrospectableClient override.
     44   virtual void Introspect(const std::string& service_name,
     45                           const dbus::ObjectPath& object_path,
     46                           const IntrospectCallback& callback) OVERRIDE {
     47     dbus::MethodCall method_call(kIntrospectableInterface, kIntrospect);
     48 
     49     dbus::ObjectProxy* object_proxy = bus_->GetObjectProxy(service_name,
     50                                                            object_path);
     51 
     52     object_proxy->CallMethod(
     53         &method_call,
     54         dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
     55         base::Bind(&IntrospectableClientImpl::OnIntrospect,
     56                    weak_ptr_factory_.GetWeakPtr(),
     57                    service_name, object_path, callback));
     58   }
     59 
     60  private:
     61   // Called by dbus:: when a response for Introspect() is recieved.
     62   void OnIntrospect(const std::string& service_name,
     63                     const dbus::ObjectPath& object_path,
     64                     const IntrospectCallback& callback,
     65                     dbus::Response* response) {
     66     // Parse response.
     67     bool success = false;
     68     std::string xml_data;
     69     if (response != NULL) {
     70       dbus::MessageReader reader(response);
     71       if (!reader.PopString(&xml_data)) {
     72         LOG(WARNING) << "Introspect response has incorrect paramters: "
     73                      << response->ToString();
     74       } else {
     75         success = true;
     76       }
     77     }
     78 
     79     // Notify client.
     80     callback.Run(service_name, object_path, xml_data, success);
     81   }
     82 
     83   dbus::Bus* bus_;
     84 
     85   // Weak pointer factory for generating 'this' pointers that might live longer
     86   // than we do.
     87   // Note: This should remain the last member so it'll be destroyed and
     88   // invalidate its weak pointers before any other members are destroyed.
     89   base::WeakPtrFactory<IntrospectableClientImpl> weak_ptr_factory_;
     90 
     91   DISALLOW_COPY_AND_ASSIGN(IntrospectableClientImpl);
     92 };
     93 
     94 // The IntrospectableClient implementation used on Linux desktop, which does
     95 // nothing.
     96 class IntrospectableClientStubImpl : public IntrospectableClient {
     97  public:
     98   // IntrospectableClient override.
     99   virtual void Introspect(const std::string& service_name,
    100                           const dbus::ObjectPath& object_path,
    101                           const IntrospectCallback& callback) OVERRIDE {
    102     VLOG(1) << "Introspect: " << service_name << " " << object_path.value();
    103     callback.Run(service_name, object_path, "", false);
    104   }
    105 };
    106 
    107 IntrospectableClient::IntrospectableClient() {
    108 }
    109 
    110 IntrospectableClient::~IntrospectableClient() {
    111 }
    112 
    113 // static
    114 std::vector<std::string>
    115 IntrospectableClient::GetInterfacesFromIntrospectResult(
    116     const std::string& xml_data) {
    117   std::vector<std::string> interfaces;
    118 
    119   XmlReader reader;
    120   if (!reader.Load(xml_data))
    121     return interfaces;
    122 
    123   do {
    124     // Skip to the next open tag, exit when done.
    125     while (!reader.SkipToElement()) {
    126       if (!reader.Read()) {
    127         return interfaces;
    128       }
    129     }
    130 
    131     // Only look at interface nodes.
    132     if (reader.NodeName() != kInterfaceNode)
    133       continue;
    134 
    135     // Skip if missing the interface name.
    136     std::string interface_name;
    137     if (!reader.NodeAttribute(kInterfaceNameAttribute, &interface_name))
    138       continue;
    139 
    140     interfaces.push_back(interface_name);
    141   } while (reader.Read());
    142 
    143   return interfaces;
    144 }
    145 
    146 // static
    147 IntrospectableClient* IntrospectableClient::Create(
    148     DBusClientImplementationType type,
    149     dbus::Bus* bus) {
    150   if (type == REAL_DBUS_CLIENT_IMPLEMENTATION)
    151     return new IntrospectableClientImpl(bus);
    152   DCHECK_EQ(STUB_DBUS_CLIENT_IMPLEMENTATION, type);
    153   return new IntrospectableClientStubImpl();
    154 }
    155 
    156 }  // namespace chromeos
    157