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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   IntrospectableClientImpl() : bus_(NULL), weak_ptr_factory_(this) {}
     36 
     37   virtual ~IntrospectableClientImpl() {
     38   }
     39 
     40   // IntrospectableClient override.
     41   virtual void Introspect(const std::string& service_name,
     42                           const dbus::ObjectPath& object_path,
     43                           const IntrospectCallback& callback) OVERRIDE {
     44     dbus::MethodCall method_call(kIntrospectableInterface, kIntrospect);
     45 
     46     dbus::ObjectProxy* object_proxy = bus_->GetObjectProxy(service_name,
     47                                                            object_path);
     48 
     49     object_proxy->CallMethod(
     50         &method_call,
     51         dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
     52         base::Bind(&IntrospectableClientImpl::OnIntrospect,
     53                    weak_ptr_factory_.GetWeakPtr(),
     54                    service_name, object_path, callback));
     55   }
     56 
     57  protected:
     58   virtual void Init(dbus::Bus* bus) OVERRIDE { bus_ = bus; }
     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 IntrospectableClient::IntrospectableClient() {
     95 }
     96 
     97 IntrospectableClient::~IntrospectableClient() {
     98 }
     99 
    100 // static
    101 std::vector<std::string>
    102 IntrospectableClient::GetInterfacesFromIntrospectResult(
    103     const std::string& xml_data) {
    104   std::vector<std::string> interfaces;
    105 
    106   XmlReader reader;
    107   if (!reader.Load(xml_data))
    108     return interfaces;
    109 
    110   do {
    111     // Skip to the next open tag, exit when done.
    112     while (!reader.SkipToElement()) {
    113       if (!reader.Read()) {
    114         return interfaces;
    115       }
    116     }
    117 
    118     // Only look at interface nodes.
    119     if (reader.NodeName() != kInterfaceNode)
    120       continue;
    121 
    122     // Skip if missing the interface name.
    123     std::string interface_name;
    124     if (!reader.NodeAttribute(kInterfaceNameAttribute, &interface_name))
    125       continue;
    126 
    127     interfaces.push_back(interface_name);
    128   } while (reader.Read());
    129 
    130   return interfaces;
    131 }
    132 
    133 // static
    134 IntrospectableClient* IntrospectableClient::Create() {
    135   return new IntrospectableClientImpl();
    136 }
    137 
    138 }  // namespace chromeos
    139