Introduce USB MIDI descriptor parser

media/midi/usb_midi_descriptor_parser_unittest.cc

Index: media/midi/usb_midi_descriptor_parser_unittest.cc
diff --git a/media/midi/usb_midi_descriptor_parser_unittest.cc b/media/midi/usb_midi_descriptor_parser_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..9570820bda09e3a27c5343bcb183d6001f802488
--- /dev/null
+++ b/media/midi/usb_midi_descriptor_parser_unittest.cc
@@ -0,0 +1,95 @@
+// Copyright (c) 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/usb_midi_descriptor_parser.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace media {
+
+namespace {
+
+TEST(UsbMidiDescriptorParserTest, ParseEmpty) {
+  UsbMidiDescriptorParser parser;
+  EXPECT_TRUE(parser.jacks().empty());
+  EXPECT_TRUE(parser.Parse(NULL, NULL, 0));
+  EXPECT_TRUE(parser.jacks().empty());
+}
+
+TEST(UsbMidiDescriptorParserTest, InvalidSize) {
+  UsbMidiDescriptorParser parser;
+  uint8 data[] = {0x04};
+  EXPECT_TRUE(parser.jacks().empty());
+  EXPECT_FALSE(parser.Parse(NULL, data, arraysize(data)));
+  EXPECT_TRUE(parser.jacks().empty());
+}
+
+TEST(UsbMidiDescriptorParserTest, NonExistingJackIsAssociated) {
+  UsbMidiDescriptorParser parser;
+  uint8 data[] = {

[Takashi Toyoshima, 2013/12/19 05:54:23]

It's better to have a comment that describes summary of following descriptor.

[yhirano, 2013/12/19 07:15:05]

Done.

+    0x09, 0x04, 0x01, 0x00, 0x02, 0x01, 0x03, 0x00, 0x00, 0x07,
+    0x24, 0x01, 0x00, 0x01, 0x07, 0x00, 0x05, 0x25, 0x01, 0x01,
+    0x01,
+  };
+  EXPECT_TRUE(parser.jacks().empty());
+  EXPECT_FALSE(parser.Parse(NULL, data, arraysize(data)));
+  EXPECT_TRUE(parser.jacks().empty());
+}
+
+TEST(UsbMidiDescriptorParserTest,
+     JacksShouldBeIgnoredWhenParserIsNotParsingAnInterface) {
+  UsbMidiDescriptorParser parser;
+  uint8 data[] = {

[Takashi Toyoshima, 2013/12/19 05:54:23]

ditto

[yhirano, 2013/12/19 07:15:05]

Done.

+    0x09, 0x05, 0x82, 0x02, 0x20, 0x00, 0x00, 0x00, 0x00, 0x05,
+    0x25, 0x01, 0x01, 0x07,
+  };
+  EXPECT_TRUE(parser.jacks().empty());
+  EXPECT_TRUE(parser.Parse(NULL, data, arraysize(data)));

[Takashi Toyoshima, 2013/12/19 05:54:23]

So, here is a question for the function design.
Why don't you return false for incomplete (unresolved?) jacks?

[yhirano, 2013/12/19 07:15:05]

Done.

[Takashi Toyoshima, 2013/12/19 07:48:48]

Ah, my original question was wrong.
I'm not sure it's useful to return true when INTERFACE descriptor is missing. Do
you have a special reason? If you have, it's better to describe it around
Parse() function comments.

[yhirano, 2013/12/19 08:05:47]

Sorry, I mis-read your comment.
There is no special reason for returning true, I only want to check that the
parser doesn't crash.
We can return false by adding some code, but we are currently skipping many
checks intentionally because checking all errors is very hard.

+  EXPECT_TRUE(parser.jacks().empty());
+}
+
+TEST(UsbMidiDescriptorParserTest, Parse) {
+  UsbMidiDescriptorParser parser;
+  uint8 data[] = {

[Takashi Toyoshima, 2013/12/19 05:54:23]

ditto

[yhirano, 2013/12/19 07:15:05]

Done.

+    0x12, 0x01, 0x10, 0x01, 0x00, 0x00, 0x00, 0x08, 0x86, 0x1a,
+    0x2d, 0x75, 0x54, 0x02, 0x00, 0x02, 0x00, 0x01, 0x09, 0x02,
+    0x75, 0x00, 0x02, 0x01, 0x00, 0x80, 0x30, 0x09, 0x04, 0x00,
+    0x00, 0x00, 0x01, 0x01, 0x00, 0x00, 0x09, 0x24, 0x01, 0x00,
+    0x01, 0x09, 0x00, 0x01, 0x01, 0x09, 0x04, 0x01, 0x00, 0x02,
+    0x01, 0x03, 0x00, 0x00, 0x07, 0x24, 0x01, 0x00, 0x01, 0x51,
+    0x00, 0x06, 0x24, 0x02, 0x01, 0x02, 0x00, 0x06, 0x24, 0x02,
+    0x01, 0x03, 0x00, 0x06, 0x24, 0x02, 0x02, 0x06, 0x00, 0x09,
+    0x24, 0x03, 0x01, 0x07, 0x01, 0x06, 0x01, 0x00, 0x09, 0x24,
+    0x03, 0x02, 0x04, 0x01, 0x02, 0x01, 0x00, 0x09, 0x24, 0x03,
+    0x02, 0x05, 0x01, 0x03, 0x01, 0x00, 0x09, 0x05, 0x02, 0x02,
+    0x20, 0x00, 0x00, 0x00, 0x00, 0x06, 0x25, 0x01, 0x02, 0x02,
+    0x03, 0x09, 0x05, 0x82, 0x02, 0x20, 0x00, 0x00, 0x00, 0x00,
+    0x05, 0x25, 0x01, 0x01, 0x07,
+  };
+  EXPECT_TRUE(parser.jacks().empty());
+  EXPECT_TRUE(parser.Parse(NULL, data, arraysize(data)));
+  ASSERT_EQ(3u, parser.jacks().size());
+
+  EXPECT_EQ(2u, parser.jacks()[0].jack_id);
+  EXPECT_EQ(0u, parser.jacks()[0].cable_number);
+  EXPECT_EQ(2u, parser.jacks()[0].GetEndpointNumber());
+  EXPECT_EQ(UsbMidiJack::OUT, parser.jacks()[0].GetDirection());
+  EXPECT_EQ(NULL, parser.jacks()[0].device);
+
+  EXPECT_EQ(3u, parser.jacks()[1].jack_id);
+  EXPECT_EQ(1u, parser.jacks()[1].cable_number);
+  EXPECT_EQ(2u, parser.jacks()[1].GetEndpointNumber());
+  EXPECT_EQ(UsbMidiJack::OUT, parser.jacks()[1].GetDirection());
+  EXPECT_EQ(NULL, parser.jacks()[1].device);
+
+  EXPECT_EQ(7u, parser.jacks()[2].jack_id);
+  EXPECT_EQ(0u, parser.jacks()[2].cable_number);
+  EXPECT_EQ(2u, parser.jacks()[2].GetEndpointNumber());
+  EXPECT_EQ(UsbMidiJack::IN, parser.jacks()[2].GetDirection());
+  EXPECT_EQ(NULL, parser.jacks()[2].device);
+}
+
+}  // namespace
+
+}  // namespace media