[MIDI] Make android MIDI port id unique

media/midi/midi_manager_usb.cc

 // Copyright 2014 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 "media/midi/midi_manager_usb.h"
 
 #include "base/callback.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
+#include "base/strings/stringprintf.h"
 #include "media/midi/usb_midi_descriptor_parser.h"
 #include "media/midi/usb_midi_device.h"
 #include "media/midi/usb_midi_input_stream.h"
 #include "media/midi/usb_midi_jack.h"
 #include "media/midi/usb_midi_output_stream.h"
 
 namespace media {
 
 MidiManagerUsb::MidiManagerUsb(scoped_ptr<UsbMidiDevice::Factory> factory)
     : device_factory_(factory.Pass()) {
@@ skipping 66 matching lines @@
                                      &jacks);
     if (!parse_result) {
       initialize_callback_.Run(MIDI_INITIALIZATION_ERROR);
       return;
     }
     std::vector<UsbMidiJack> input_jacks;
     for (size_t j = 0; j < jacks.size(); ++j) {
       if (jacks[j].direction() == UsbMidiJack::DIRECTION_OUT) {
         output_streams_.push_back(new UsbMidiOutputStream(jacks[j]));
         // TODO(yhirano): Set appropriate properties.
-        AddOutputPort(MidiPortInfo());
+        MidiPortInfo port;
+        port.id = base::StringPrintf("port-%zu-%zu", i, j);

[Takashi Toyoshima, 2014/08/28 11:52:11]

I might be wrong, but the i and j mean the USB port location right?
I forget what is this, so maybe adding some comments here will be helpful:)

If it is easy to use USB PID/VID in addition to USB port location here? It is
not mandatory, but would be better.

[yhirano, 2014/08/28 13:09:14]

They are just indices and are not meaningful. I will add PID/VID, but the USB
descriptor parser need to be fixed for it, so as a quirk I would propose this
CL.
Why I want to fix it now is, I am introducing MIDIInputMap and MIDIOutputMap.
Previously, duplicated IDs were no harm (while it violated the spec), but when
MIDIInputMap and MIDIOutMap are introduced duplicated IDs will be a serious
problem because they will be used as keys.

+        AddOutputPort(port);
       } else {
         DCHECK_EQ(jacks[j].direction(), UsbMidiJack::DIRECTION_IN);
         input_jacks.push_back(jacks[j]);
         // TODO(yhirano): Set appropriate properties.
-        AddInputPort(MidiPortInfo());
+        MidiPortInfo port;
+        port.id = base::StringPrintf("port-%zu-%zu", i, j);
+        AddInputPort(port);
       }
     }
     input_stream_.reset(new UsbMidiInputStream(input_jacks, this));
   }
   initialize_callback_.Run(MIDI_OK);
 }
 
 }  // namespace media