TextRenderer only pushes new cues downstream

The TextTrack subsystem in Blink unconditionally satisfies a request
to add a new text cue to the text track cue list, relying on the
upstream demuxers to filter out cues that have already been added to
that list.

The TextRenderer now manages a map of time range objects, to keep
track of which cues (based on their start times) have already been
pushed downstream prior to the current seek.

BUG=230708

Review URL: https://codereview.chromium.org/151103005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249845 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 147 insertions, 0 deletions

diff --git a/media/base/text_ranges_unittest.cc b/media/base/text_ranges_unittest.cc
new file mode 100644
index 0000000..7de0514
--- /dev/null
+++ b/media/base/text_ranges_unittest.cc
@@ -0,0 +1,147 @@
+// 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/base/text_ranges.h"
+
+#include "base/time/time.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace media {
+
+class TextRangesTest : public ::testing::Test {
+ protected:
+  bool AddCue(int seconds) {
+    return ranges_.AddCue(base::TimeDelta::FromSeconds(seconds));
+  }
+
+  void Reset() {
+    ranges_.Reset();
+  }
+
+  size_t RangeCount() {
+    return ranges_.RangeCountForTesting();
+  }
+
+  TextRanges ranges_;
+};
+
+TEST_F(TextRangesTest, TestEmptyRanges) {
+  // Create a new active range, with t=5.
+  EXPECT_TRUE(AddCue(5));
+
+  // Create a new active range, with t=2.
+  Reset();
+  EXPECT_TRUE(AddCue(2));
+
+  // Create a new active range, with t=8.
+  Reset();
+  EXPECT_TRUE(AddCue(8));
+
+  Reset();
+
+  // Make range [2, 2] active.
+  EXPECT_FALSE(AddCue(2));
+  EXPECT_EQ(RangeCount(), 3U);
+
+  // Coalesce first two ranges: [2, 5].
+  EXPECT_FALSE(AddCue(5));
+  EXPECT_EQ(RangeCount(), 2U);
+
+  // Coalesce first two ranges: [2, 8].
+  EXPECT_FALSE(AddCue(8));
+  EXPECT_EQ(RangeCount(), 1U);
+
+  // Add new cue to end of (only) range.
+  EXPECT_TRUE(AddCue(9));
+  EXPECT_EQ(RangeCount(), 1U);
+}
+
+TEST_F(TextRangesTest, TestOneRange) {
+  // Create a new active range, with t=0.
+  EXPECT_TRUE(AddCue(0));
+
+  // Add cues to end of existing range.
+  EXPECT_TRUE(AddCue(1));
+  EXPECT_TRUE(AddCue(4));
+
+  Reset();
+  EXPECT_FALSE(AddCue(2));
+  EXPECT_FALSE(AddCue(3));
+  EXPECT_FALSE(AddCue(4));
+}
+
+TEST_F(TextRangesTest, TestDuplicateLast) {
+  // Create a new active range, with t=0.
+  EXPECT_TRUE(AddCue(0));
+  EXPECT_TRUE(AddCue(1));
+
+  Reset();
+  EXPECT_FALSE(AddCue(1));
+  EXPECT_TRUE(AddCue(1));
+}
+
+TEST_F(TextRangesTest, TestTwoRanges) {
+  // Create a new active range, with t=0.
+  EXPECT_TRUE(AddCue(0));
+
+  // Add cue to end of existing range.
+  EXPECT_TRUE(AddCue(2));
+
+  Reset();
+
+  // Create a new active range, with t=4.
+  EXPECT_TRUE(AddCue(4));
+
+  // Add a new cue to end of last (active) range.
+  EXPECT_TRUE(AddCue(5));
+
+  Reset();
+
+  // Make first range active.
+  EXPECT_FALSE(AddCue(0));
+  EXPECT_FALSE(AddCue(2));
+
+  // Expand first range.
+  EXPECT_TRUE(AddCue(3));
+
+  // Coalesce first and second ranges.
+  EXPECT_FALSE(AddCue(4));
+  EXPECT_EQ(RangeCount(), 1U);
+}
+
+TEST_F(TextRangesTest, TestThreeRanges) {
+  // Create a new active range, with t=0.
+  EXPECT_TRUE(AddCue(0));
+
+  // Add cue to end of existing range.
+  EXPECT_TRUE(AddCue(2));
+
+  Reset();
+
+  // Create a new active range, with t=4.
+  EXPECT_TRUE(AddCue(4));
+
+  // Add a new cue to end of last (active) range.
+  EXPECT_TRUE(AddCue(5));
+
+  Reset();
+
+  // Create a new active range, in between the other two.
+  EXPECT_TRUE(AddCue(3));
+
+  // Coalesce middle and last ranges.
+  EXPECT_FALSE(AddCue(4));
+
+  Reset();
+
+  // Make first range active.
+  EXPECT_FALSE(AddCue(0));
+  EXPECT_FALSE(AddCue(2));
+
+  // Coalesce first and last ranges.
+  EXPECT_FALSE(AddCue(3));
+  EXPECT_EQ(RangeCount(), 1U);
+}
+
+}  // namespace media