device: implement "nofake" hint to exclude dummy devices from discovery

usage example:

osmosdr::device_t hint( "nofake" );
osmosdr::devices_t devs = osmosdr::device::find( hint );

include/osmosdr/device.h

@@ -101,6 +101,9 @@ namespace osmosdr {
      * The device hint should be used to narrow down the search
      * to particular transport types and/or transport arguments.
      *
+     * The device hint "nofake" switches off dummy devices created
+     * by "file" (and other) implementations.
+     *
      * \param hint a partially (or fully) filled in logical device
      * \return a vector of logical devices for all radios on the system
      */

lib/device.cc

@@ -119,6 +119,11 @@ devices_t device::find(const device_t &hint)
 {
   boost::mutex::scoped_lock lock(_device_mutex);
 
+  bool fake = true;
+
+  if ( hint.count("nofake") )
+    fake = false;
+
   devices_t devices;
 
 #ifdef ENABLE_OSMOSDR
@@ -150,7 +155,7 @@ devices_t device::find(const device_t &hint)
     devices.push_back( device_t(dev) );
 #endif
 #ifdef ENABLE_NETSDR
-  BOOST_FOREACH( std::string dev, netsdr_source_c::get_devices( true ) )
+  BOOST_FOREACH( std::string dev, netsdr_source_c::get_devices( fake ) )
     devices.push_back( device_t(dev) );
 #endif
 
@@ -159,11 +164,11 @@ devices_t device::find(const device_t &hint)
    * in a graphical interface etc... */
 
 #ifdef ENABLE_RTL_TCP
-  BOOST_FOREACH( std::string dev, rtl_tcp_source_c::get_devices() )
+  BOOST_FOREACH( std::string dev, rtl_tcp_source_c::get_devices( fake ) )
     devices.push_back( device_t(dev) );
 #endif
 #ifdef ENABLE_FILE
-  BOOST_FOREACH( std::string dev, file_source_c::get_devices() )
+  BOOST_FOREACH( std::string dev, file_source_c::get_devices( fake ) )
     devices.push_back( device_t(dev) );
 #endif
 

lib/file/file_source_c.cc

@@ -102,14 +102,17 @@ std::string file_source_c::name()
   return "IQ File Source";
 }
 
-std::vector<std::string> file_source_c::get_devices()
+std::vector<std::string> file_source_c::get_devices( bool fake )
 {
   std::vector<std::string> devices;
 
-  std::string args = "file='/path/to/your/file'";
-  args += ",rate=1e6,freq=100e6,repeat=true,throttle=true";
-  args += ",label='Complex Sampled (IQ) File'";
-  devices.push_back( args );
+  if ( fake )
+  {
+    std::string args = "file='/path/to/your/file'";
+    args += ",rate=1e6,freq=100e6,repeat=true,throttle=true";
+    args += ",label='Complex Sampled (IQ) File'";
+    devices.push_back( args );
+  }
 
   return devices;
 }

lib/file/file_source_c.h

@@ -45,7 +45,7 @@ public:
 
   std::string name();
 
-  static std::vector< std::string > get_devices();
+  static std::vector< std::string > get_devices( bool fake = false );
 
   size_t get_num_channels( void );
 

lib/rtl_tcp/rtl_tcp_source_c.cc

@@ -151,13 +151,16 @@ std::string rtl_tcp_source_c::name()
   return "RTL TCP Client";
 }
 
-std::vector<std::string> rtl_tcp_source_c::get_devices()
+std::vector<std::string> rtl_tcp_source_c::get_devices( bool fake )
 {
   std::vector<std::string> devices;
 
-  std::string args = "rtl_tcp=localhost:1234";
-  args += ",label='RTL-SDR Spectrum Server'";
-  devices.push_back( args );
+  if ( fake )
+  {
+    std::string args = "rtl_tcp=localhost:1234";
+    args += ",label='RTL-SDR Spectrum Server'";
+    devices.push_back( args );
+  }
 
   return devices;
 }

lib/rtl_tcp/rtl_tcp_source_c.h

@@ -46,7 +46,7 @@ public:
 
   std::string name();
 
-  static std::vector< std::string > get_devices();
+  static std::vector< std::string > get_devices( bool fake = false );
 
   size_t get_num_channels( void );