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      1 /*
      2  * libjingle
      3  * Copyright 2004--2011, Google Inc.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions are met:
      7  *
      8  *  1. Redistributions of source code must retain the above copyright notice,
      9  *     this list of conditions and the following disclaimer.
     10  *  2. Redistributions in binary form must reproduce the above copyright notice,
     11  *     this list of conditions and the following disclaimer in the documentation
     12  *     and/or other materials provided with the distribution.
     13  *  3. The name of the author may not be used to endorse or promote products
     14  *     derived from this software without specific prior written permission.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
     17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
     19  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     20  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
     22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  */
     27 
     28 #ifndef TALK_BASE_DBUS_H_
     29 #define TALK_BASE_DBUS_H_
     30 
     31 #ifdef HAVE_DBUS_GLIB
     32 
     33 #include <dbus/dbus.h>
     34 
     35 #include <string>
     36 #include <vector>
     37 
     38 #include "talk/base/libdbusglibsymboltable.h"
     39 #include "talk/base/messagehandler.h"
     40 #include "talk/base/thread.h"
     41 
     42 namespace talk_base {
     43 
     44 #define DBUS_TYPE                   "type"
     45 #define DBUS_SIGNAL                 "signal"
     46 #define DBUS_PATH                   "path"
     47 #define DBUS_INTERFACE              "interface"
     48 #define DBUS_MEMBER                 "member"
     49 
     50 #ifdef CHROMEOS
     51 #define CROS_PM_PATH                "/"
     52 #define CROS_PM_INTERFACE           "org.chromium.PowerManager"
     53 #define CROS_SIG_POWERCHANGED       "PowerStateChanged"
     54 #define CROS_VALUE_SLEEP            "mem"
     55 #define CROS_VALUE_RESUME           "on"
     56 #else
     57 #define UP_PATH                     "/org/freedesktop/UPower"
     58 #define UP_INTERFACE                "org.freedesktop.UPower"
     59 #define UP_SIG_SLEEPING             "Sleeping"
     60 #define UP_SIG_RESUMING             "Resuming"
     61 #endif  // CHROMEOS
     62 
     63 // Wraps a DBus messages.
     64 class DBusSigMessageData : public TypedMessageData<DBusMessage *> {
     65  public:
     66   explicit DBusSigMessageData(DBusMessage *message);
     67   ~DBusSigMessageData();
     68 };
     69 
     70 // DBusSigFilter is an abstract class that defines the interface of DBus
     71 // signal handling.
     72 // The subclasses implement ProcessSignal() for various purposes.
     73 // When a DBus signal comes, a DSM_SIGNAL message is posted to the caller thread
     74 // which will then invokes ProcessSignal().
     75 class DBusSigFilter : protected MessageHandler {
     76  public:
     77   enum DBusSigMessage { DSM_SIGNAL };
     78 
     79   // This filter string should ususally come from BuildFilterString()
     80   explicit DBusSigFilter(const std::string &filter)
     81       : caller_thread_(Thread::Current()), filter_(filter) {
     82   }
     83 
     84   // Builds a DBus monitor filter string from given DBus path, interface, and
     85   // member.
     86   // See http://dbus.freedesktop.org/doc/api/html/group__DBusConnection.html
     87   static std::string BuildFilterString(const std::string &path,
     88                                        const std::string &interface,
     89                                        const std::string &member);
     90 
     91   // Handles callback on DBus messages by DBus system.
     92   static DBusHandlerResult DBusCallback(DBusConnection *dbus_conn,
     93                                         DBusMessage *message,
     94                                         void *instance);
     95 
     96   // Handles callback on DBus messages to each DBusSigFilter instance.
     97   DBusHandlerResult Callback(DBusMessage *message);
     98 
     99   // From MessageHandler.
    100   virtual void OnMessage(Message *message);
    101 
    102   // Returns the DBus monitor filter string.
    103   const std::string &filter() const { return filter_; }
    104 
    105  private:
    106   // On caller thread.
    107   virtual void ProcessSignal(DBusMessage *message) = 0;
    108 
    109   Thread *caller_thread_;
    110   const std::string filter_;
    111 };
    112 
    113 // DBusMonitor is a class for DBus signal monitoring.
    114 //
    115 // The caller-thread calls AddFilter() first to add the signals that it wants to
    116 // monitor and then calls StartMonitoring() to start the monitoring.
    117 // This will create a worker-thread which listens on DBus connection and sends
    118 // DBus signals back through the callback.
    119 // The worker-thread will be running forever until either StopMonitoring() is
    120 // called from the caller-thread or the worker-thread hit some error.
    121 //
    122 // Programming model:
    123 //   1. Caller-thread: Creates an object of DBusMonitor.
    124 //   2. Caller-thread: Calls DBusMonitor::AddFilter() one or several times.
    125 //   3. Caller-thread: StartMonitoring().
    126 //      ...
    127 //   4. Worker-thread: DBus signal recieved. Post a message to caller-thread.
    128 //   5. Caller-thread: DBusFilterBase::ProcessSignal() is invoked.
    129 //      ...
    130 //   6. Caller-thread: StopMonitoring().
    131 //
    132 // Assumption:
    133 //   AddFilter(), StartMonitoring(), and StopMonitoring() methods are called by
    134 //   a single thread. Hence, there is no need to make them thread safe.
    135 class DBusMonitor {
    136  public:
    137   // Status of DBus monitoring.
    138   enum DBusMonitorStatus {
    139     DMS_NOT_INITIALIZED,  // Not initialized.
    140     DMS_INITIALIZING,     // Initializing the monitoring thread.
    141     DMS_RUNNING,          // Monitoring.
    142     DMS_STOPPED,          // Not monitoring. Stopped normally.
    143     DMS_FAILED,           // Not monitoring. Failed.
    144   };
    145 
    146   // Returns the DBus-Glib symbol table.
    147   // We should only use this function to access DBus-Glib symbols.
    148   static LibDBusGlibSymbolTable *GetDBusGlibSymbolTable();
    149 
    150   // Creates an instance of DBusMonitor.
    151   static DBusMonitor *Create(DBusBusType type);
    152   ~DBusMonitor();
    153 
    154   // Adds a filter to DBusMonitor.
    155   bool AddFilter(DBusSigFilter *filter);
    156 
    157   // Starts DBus message monitoring.
    158   bool StartMonitoring();
    159 
    160   // Stops DBus message monitoring.
    161   bool StopMonitoring();
    162 
    163   // Gets the status of DBus monitoring.
    164   DBusMonitorStatus GetStatus();
    165 
    166  private:
    167   // Forward declaration. Defined in the .cc file.
    168   class DBusMonitoringThread;
    169 
    170   explicit DBusMonitor(DBusBusType type);
    171 
    172   // Updates status_ when monitoring status has changed.
    173   void OnMonitoringStatusChanged(DBusMonitorStatus status);
    174 
    175   DBusBusType type_;
    176   DBusMonitorStatus status_;
    177   DBusMonitoringThread *monitoring_thread_;
    178   std::vector<DBusSigFilter *> filter_list_;
    179 };
    180 
    181 }  // namespace talk_base
    182 
    183 #endif  // HAVE_DBUS_GLIB
    184 
    185 #endif  // TALK_BASE_DBUS_H_
    186