Web MIDI: minimum support for Linux and Chrome OS

This change enables Web MIDI API on Linux and Chrome OS.
Only Sending functionality works with this first experimental change.

BUG=303601

Review URL: https://codereview.chromium.org/111443005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241524 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 182 insertions, 2 deletions

diff --git a/media/media.gyp b/media/media.gyp
index fb844de..d70938d 100644
--- a/media/media.gyp
+++ b/media/media.gyp
@@ -407,6 +407,8 @@
         'filters/wsola_internals.h',
         'midi/midi_manager.cc',
         'midi/midi_manager.h',
+        'midi/midi_manager_linux.cc',
+        'midi/midi_manager_linux.h',
         'midi/midi_manager_mac.cc',
         'midi/midi_manager_mac.h',
         'midi/midi_message_queue.cc',
diff --git a/media/midi/midi_manager.cc b/media/midi/midi_manager.cc
index 6d3f1d3..5ef103f 100644
--- a/media/midi/midi_manager.cc
+++ b/media/midi/midi_manager.cc
@@ -9,8 +9,8 @@
 
 namespace media {
 
-#if !defined(OS_MACOSX) && !defined(OS_WIN)
-// TODO(crogers): implement MIDIManager for other platforms.
+#if defined(OS_ANDROID) || defined(OS_IOS)
+// TODO(toyoshim): implement MIDIManager for other platforms.
 MIDIManager* MIDIManager::Create() {
   return NULL;
 }
diff --git a/media/midi/midi_manager_linux.cc b/media/midi/midi_manager_linux.cc
new file mode 100644
index 0000000..712d53d
--- /dev/null
+++ b/media/midi/midi_manager_linux.cc
@@ -0,0 +1,139 @@
+// Copyright 2013 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_linux.h"
+
+#include <fcntl.h>
+#include <sound/asound.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include "base/bind.h"
+#include "base/debug/trace_event.h"
+#include "base/files/file.h"
+#include "base/files/file_enumerator.h"
+#include "base/files/file_path.h"
+#include "base/memory/ref_counted.h"
+#include "base/message_loop/message_loop.h"
+#include "base/strings/string_util.h"
+#include "base/threading/thread.h"
+#include "media/midi/midi_port_info.h"
+
+namespace media {
+namespace {
+
+const char kDevSnd[] = "/dev/snd";
+const char kMIDIPattern[] = "midi*";
+const char kUnknown[] = "[unknown]";
+
+}  // namespace
+
+class MIDIManagerLinux::MIDIDeviceInfo
+    : public base::RefCounted<MIDIDeviceInfo> {
+ public:
+  MIDIDeviceInfo(MIDIManagerLinux* manager, base::FilePath path)
+      : flags_(0) {
+    file_ = base::File(path,
+                       base::File::FLAG_OPEN |
+                       base::File::FLAG_READ |
+                       base::File::FLAG_WRITE);
+    if (file_.error() != base::File::FILE_OK)
+      return;
+
+    struct snd_rawmidi_info info = {};
+    if (ioctl(file_.GetPlatformFile(), SNDRV_RAWMIDI_IOCTL_INFO, &info))
+      return;
+
+    flags_ = info.flags;
+    const char* name = reinterpret_cast<const char*>(&info.name[0]);
+    port_info_ = MIDIPortInfo(path.value(), kUnknown, name, kUnknown);
+  }
+
+  void Send(MIDIManagerClient* client, const std::vector<uint8>& data) {
+    if (!file_.IsValid())
+      return;
+    file_.WriteAtCurrentPos(reinterpret_cast<const char*>(&data[0]),
+                            data.size());
+    base::MessageLoop::current()->PostTask(
+        FROM_HERE,
+        base::Bind(&MIDIManagerClient::AccumulateMIDIBytesSent,
+                   base::Unretained(client), data.size()));
+  }
+
+  bool HasInputPort() const { return flags_ & SNDRV_RAWMIDI_INFO_INPUT; }
+  bool HasOutputPort() const { return flags_ & SNDRV_RAWMIDI_INFO_OUTPUT; }
+  const MIDIPortInfo& GetMIDIPortInfo() const { return port_info_; }
+
+ private:
+  friend class base::RefCounted<MIDIDeviceInfo>;
+  virtual ~MIDIDeviceInfo() {}
+
+  base::File file_;
+  int flags_;
+  MIDIPortInfo port_info_;
+
+  DISALLOW_COPY_AND_ASSIGN(MIDIDeviceInfo);
+};
+
+MIDIManagerLinux::MIDIManagerLinux()
+    : send_thread_("MIDISendThread") {
+}
+
+bool MIDIManagerLinux::Initialize() {
+  TRACE_EVENT0("midi", "MIDIManagerMac::Initialize");
+
+  base::FilePath path(kDevSnd);
+  base::FileEnumerator enumerator(path, false, base::FileEnumerator::FILES,
+                                  FILE_PATH_LITERAL(kMIDIPattern));
+  for (base::FilePath name = enumerator.Next();
+       !name.empty();
+       name = enumerator.Next()) {
+    scoped_refptr<MIDIDeviceInfo> device = new MIDIDeviceInfo(this, name);
+    if (device->HasInputPort()) {
+      in_devices_.push_back(device);
+      AddInputPort(device->GetMIDIPortInfo());
+    }
+    if (device->HasOutputPort()) {
+      out_devices_.push_back(device);
+      AddOutputPort(device->GetMIDIPortInfo());
+    }
+  }
+  return true;
+}
+
+MIDIManagerLinux::~MIDIManagerLinux() {
+  send_thread_.Stop();
+}
+
+void MIDIManagerLinux::DispatchSendMIDIData(MIDIManagerClient* client,
+                                            uint32 port_index,
+                                            const std::vector<uint8>& data,
+                                            double timestamp) {
+  if (out_devices_.size() <= port_index)
+    return;
+
+  base::TimeDelta delay;
+  if (timestamp != 0.0) {
+    base::TimeTicks time_to_send =
+        base::TimeTicks() + base::TimeDelta::FromMicroseconds(
+            timestamp * base::Time::kMicrosecondsPerSecond);
+    delay = std::max(time_to_send - base::TimeTicks::Now(), base::TimeDelta());
+  }
+
+  if (!send_thread_.IsRunning())
+    send_thread_.Start();
+
+  scoped_refptr<MIDIDeviceInfo> device = out_devices_[port_index];
+  send_thread_.message_loop()->PostDelayedTask(
+      FROM_HERE,
+      base::Bind(&MIDIDeviceInfo::Send, device, client, data),
+      delay);
+}
+
+MIDIManager* MIDIManager::Create() {
+  return new MIDIManagerLinux();
+}
+
+}  // namespace media
diff --git a/media/midi/midi_manager_linux.h b/media/midi/midi_manager_linux.h
new file mode 100644
index 0000000..f033f14
--- /dev/null
+++ b/media/midi/midi_manager_linux.h
@@ -0,0 +1,39 @@
+// Copyright 2013 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_LINUX_H_
+#define MEDIA_MIDI_MIDI_MANAGER_LINUX_H_
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/threading/thread.h"
+#include "media/midi/midi_manager.h"
+
+namespace media {
+
+class MIDIManagerLinux : public MIDIManager {
+ public:
+  MIDIManagerLinux();
+  virtual ~MIDIManagerLinux();
+
+  // MIDIManager implementation.
+  virtual bool Initialize() OVERRIDE;
+  virtual void DispatchSendMIDIData(MIDIManagerClient* client,
+                                    uint32 port_index,
+                                    const std::vector<uint8>& data,
+                                    double timestamp) OVERRIDE;
+
+ private:
+  class MIDIDeviceInfo;
+  std::vector<scoped_refptr<MIDIDeviceInfo> > in_devices_;
+  std::vector<scoped_refptr<MIDIDeviceInfo> > out_devices_;
+  base::Thread send_thread_;
+  DISALLOW_COPY_AND_ASSIGN(MIDIManagerLinux);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_MIDI_MIDI_MANAGER_LINUX_H_