Improve MidiManagerAlsa manufacturer reporting

media/midi/midi_manager_alsa.h

 // 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.
 
 #ifndef MEDIA_MIDI_MIDI_MANAGER_ALSA_H_
 #define MEDIA_MIDI_MIDI_MANAGER_ALSA_H_
 
 #include <alsa/asoundlib.h>
 #include <map>
 #include <vector>
 
 #include "base/basictypes.h"
+#include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/thread.h"
 #include "media/midi/midi_manager.h"
 
+#if defined(USE_UDEV)
+#include "device/udev_linux/scoped_udev.h"
+#endif  // defined(USE_UDEV)
+
 namespace media {
 
-class MidiManagerAlsa : public MidiManager {
+class MEDIA_EXPORT MidiManagerAlsa : public MidiManager {
  public:
   MidiManagerAlsa();
   ~MidiManagerAlsa() override;
 
   // MidiManager implementation.
   void StartInitialization() override;
   void DispatchSendMidiData(MidiManagerClient* client,
                             uint32 port_index,
                             const std::vector<uint8>& data,
                             double timestamp) override;
 
  private:
+  FRIEND_TEST_ALL_PREFIXES(MidiManagerAlsaTest, ExtractManufacturer);
+  FRIEND_TEST_ALL_PREFIXES(MidiManagerAlsaTest, UdevEscape);
+
   // An internal callback that runs on MidiSendThread.
   void SendMidiData(uint32 port_index,
                     const std::vector<uint8>& data);
 
   void EventReset();
   void EventLoop();
 
+  // Extracts the manufacturer using heuristics and a variety of sources.
+  static std::string ExtractManufacturer(
+      const std::string& udev_id_vendor_enc,
+      const std::string& udev_id_vendor_id,
+      const std::string& udev_id_vendor_from_database,
+      const std::string& alsa_name,
+      const std::string& alsa_longname);
+
+  // Decodes just \xXX in strings.
+  static std::string UnescapeUdev(const std::string& s);
+
   // Alsa seq handles.
   snd_seq_t* in_client_;
   snd_seq_t* out_client_;
   int out_client_id_;
 
   // One input port, many output ports.
   int in_port_;
   std::vector<int> out_ports_;
 
   // Mapping from Alsa client:port to our index.
   typedef std::map<int, uint32> SourceMap;
   SourceMap source_map_;
 
   // Alsa event <-> MIDI coders.
   snd_midi_event_t* decoder_;
   typedef std::vector<snd_midi_event_t*> EncoderList;
   EncoderList encoders_;
 
+  // udev, for querying hardware devices.
+#if defined(USE_UDEV)
+  device::ScopedUdevPtr udev_;
+#endif  // defined(USE_UDEV)
+
   base::Thread send_thread_;
   base::Thread event_thread_;
 
   bool event_thread_shutdown_; // guarded by shutdown_lock_
   base::Lock shutdown_lock_; // guards event_thread_shutdown_
 
   DISALLOW_COPY_AND_ASSIGN(MidiManagerAlsa);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_MIDI_MIDI_MANAGER_ALSA_H_