Adding upstream version 115.8.0esr.upstream/115.8.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 935 insertions, 0 deletions

diff --git a/image/test/gtest/TestStreamingLexer.cpp b/image/test/gtest/TestStreamingLexer.cpp
new file mode 100644
index 0000000000..c83569a7b9
--- /dev/null
+++ b/image/test/gtest/TestStreamingLexer.cpp
@@ -0,0 +1,935 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+
+#include "Common.h"
+#include "mozilla/Vector.h"
+#include "StreamingLexer.h"
+
+using namespace mozilla;
+using namespace mozilla::image;
+
+enum class TestState {
+  ONE,
+  TWO,
+  THREE,
+  UNBUFFERED,
+  TRUNCATED_SUCCESS,
+  TRUNCATED_FAILURE
+};
+
+void CheckLexedData(const char* aData, size_t aLength, size_t aOffset,
+                    size_t aExpectedLength) {
+  EXPECT_TRUE(aLength == aExpectedLength);
+
+  for (size_t i = 0; i < aLength; ++i) {
+    EXPECT_EQ(aData[i], char(aOffset + i + 1));
+  }
+}
+
+LexerTransition<TestState> DoLex(TestState aState, const char* aData,
+                                 size_t aLength) {
+  switch (aState) {
+    case TestState::ONE:
+      CheckLexedData(aData, aLength, 0, 3);
+      return Transition::To(TestState::TWO, 3);
+    case TestState::TWO:
+      CheckLexedData(aData, aLength, 3, 3);
+      return Transition::To(TestState::THREE, 3);
+    case TestState::THREE:
+      CheckLexedData(aData, aLength, 6, 3);
+      return Transition::TerminateSuccess();
+    case TestState::TRUNCATED_SUCCESS:
+      return Transition::TerminateSuccess();
+    case TestState::TRUNCATED_FAILURE:
+      return Transition::TerminateFailure();
+    default:
+      MOZ_CRASH("Unexpected or unhandled TestState");
+  }
+}
+
+LexerTransition<TestState> DoLexWithUnbuffered(
+    TestState aState, const char* aData, size_t aLength,
+    Vector<char>& aUnbufferedVector) {
+  switch (aState) {
+    case TestState::ONE:
+      CheckLexedData(aData, aLength, 0, 3);
+      return Transition::ToUnbuffered(TestState::TWO, TestState::UNBUFFERED, 3);
+    case TestState::TWO:
+      CheckLexedData(aUnbufferedVector.begin(), aUnbufferedVector.length(), 3,
+                     3);
+      return Transition::To(TestState::THREE, 3);
+    case TestState::THREE:
+      CheckLexedData(aData, aLength, 6, 3);
+      return Transition::TerminateSuccess();
+    case TestState::UNBUFFERED:
+      EXPECT_TRUE(aLength <= 3);
+      EXPECT_TRUE(aUnbufferedVector.append(aData, aLength));
+      return Transition::ContinueUnbuffered(TestState::UNBUFFERED);
+    default:
+      MOZ_CRASH("Unexpected or unhandled TestState");
+  }
+}
+
+LexerTransition<TestState> DoLexWithUnbufferedTerminate(TestState aState,
+                                                        const char* aData,
+                                                        size_t aLength) {
+  switch (aState) {
+    case TestState::ONE:
+      CheckLexedData(aData, aLength, 0, 3);
+      return Transition::ToUnbuffered(TestState::TWO, TestState::UNBUFFERED, 3);
+    case TestState::UNBUFFERED:
+      return Transition::TerminateSuccess();
+    default:
+      MOZ_CRASH("Unexpected or unhandled TestState");
+  }
+}
+
+LexerTransition<TestState> DoLexWithYield(TestState aState, const char* aData,
+                                          size_t aLength) {
+  switch (aState) {
+    case TestState::ONE:
+      CheckLexedData(aData, aLength, 0, 3);
+      return Transition::ToAfterYield(TestState::TWO);
+    case TestState::TWO:
+      CheckLexedData(aData, aLength, 0, 3);
+      return Transition::To(TestState::THREE, 6);
+    case TestState::THREE:
+      CheckLexedData(aData, aLength, 3, 6);
+      return Transition::TerminateSuccess();
+    default:
+      MOZ_CRASH("Unexpected or unhandled TestState");
+  }
+}
+
+LexerTransition<TestState> DoLexWithTerminateAfterYield(TestState aState,
+                                                        const char* aData,
+                                                        size_t aLength) {
+  switch (aState) {
+    case TestState::ONE:
+      CheckLexedData(aData, aLength, 0, 3);
+      return Transition::ToAfterYield(TestState::TWO);
+    case TestState::TWO:
+      return Transition::TerminateSuccess();
+    default:
+      MOZ_CRASH("Unexpected or unhandled TestState");
+  }
+}
+
+LexerTransition<TestState> DoLexWithZeroLengthStates(TestState aState,
+                                                     const char* aData,
+                                                     size_t aLength) {
+  switch (aState) {
+    case TestState::ONE:
+      EXPECT_TRUE(aLength == 0);
+      return Transition::To(TestState::TWO, 0);
+    case TestState::TWO:
+      EXPECT_TRUE(aLength == 0);
+      return Transition::To(TestState::THREE, 9);
+    case TestState::THREE:
+      CheckLexedData(aData, aLength, 0, 9);
+      return Transition::TerminateSuccess();
+    default:
+      MOZ_CRASH("Unexpected or unhandled TestState");
+  }
+}
+
+LexerTransition<TestState> DoLexWithZeroLengthStatesAtEnd(TestState aState,
+                                                          const char* aData,
+                                                          size_t aLength) {
+  switch (aState) {
+    case TestState::ONE:
+      CheckLexedData(aData, aLength, 0, 9);
+      return Transition::To(TestState::TWO, 0);
+    case TestState::TWO:
+      EXPECT_TRUE(aLength == 0);
+      return Transition::To(TestState::THREE, 0);
+    case TestState::THREE:
+      EXPECT_TRUE(aLength == 0);
+      return Transition::TerminateSuccess();
+    default:
+      MOZ_CRASH("Unexpected or unhandled TestState");
+  }
+}
+
+LexerTransition<TestState> DoLexWithZeroLengthYield(TestState aState,
+                                                    const char* aData,
+                                                    size_t aLength) {
+  switch (aState) {
+    case TestState::ONE:
+      EXPECT_EQ(0u, aLength);
+      return Transition::ToAfterYield(TestState::TWO);
+    case TestState::TWO:
+      EXPECT_EQ(0u, aLength);
+      return Transition::To(TestState::THREE, 9);
+    case TestState::THREE:
+      CheckLexedData(aData, aLength, 0, 9);
+      return Transition::TerminateSuccess();
+    default:
+      MOZ_CRASH("Unexpected or unhandled TestState");
+  }
+}
+
+LexerTransition<TestState> DoLexWithZeroLengthStatesUnbuffered(
+    TestState aState, const char* aData, size_t aLength) {
+  switch (aState) {
+    case TestState::ONE:
+      EXPECT_TRUE(aLength == 0);
+      return Transition::ToUnbuffered(TestState::TWO, TestState::UNBUFFERED, 0);
+    case TestState::TWO:
+      EXPECT_TRUE(aLength == 0);
+      return Transition::To(TestState::THREE, 9);
+    case TestState::THREE:
+      CheckLexedData(aData, aLength, 0, 9);
+      return Transition::TerminateSuccess();
+    case TestState::UNBUFFERED:
+      ADD_FAILURE() << "Should not enter zero-length unbuffered state";
+      return Transition::TerminateFailure();
+    default:
+      MOZ_CRASH("Unexpected or unhandled TestState");
+  }
+}
+
+LexerTransition<TestState> DoLexWithZeroLengthStatesAfterUnbuffered(
+    TestState aState, const char* aData, size_t aLength) {
+  switch (aState) {
+    case TestState::ONE:
+      EXPECT_TRUE(aLength == 0);
+      return Transition::ToUnbuffered(TestState::TWO, TestState::UNBUFFERED, 9);
+    case TestState::TWO:
+      EXPECT_TRUE(aLength == 0);
+      return Transition::To(TestState::THREE, 0);
+    case TestState::THREE:
+      EXPECT_TRUE(aLength == 0);
+      return Transition::TerminateSuccess();
+    case TestState::UNBUFFERED:
+      CheckLexedData(aData, aLength, 0, 9);
+      return Transition::ContinueUnbuffered(TestState::UNBUFFERED);
+    default:
+      MOZ_CRASH("Unexpected or unhandled TestState");
+  }
+}
+
+class ImageStreamingLexer : public ::testing::Test {
+ public:
+  // Note that mLexer is configured to enter TerminalState::FAILURE immediately
+  // if the input data is truncated. We don't expect that to happen in most
+  // tests, so we want to detect that issue. If a test needs a different
+  // behavior, we create a special StreamingLexer just for that test.
+  ImageStreamingLexer()
+      : mLexer(Transition::To(TestState::ONE, 3),
+               Transition::TerminateFailure()),
+        mSourceBuffer(new SourceBuffer),
+        mIterator(mSourceBuffer->Iterator()),
+        mExpectNoResume(new ExpectNoResume),
+        mCountResumes(new CountResumes) {}
+
+ protected:
+  void CheckTruncatedState(StreamingLexer<TestState>& aLexer,
+                           TerminalState aExpectedTerminalState,
+                           nsresult aCompletionStatus = NS_OK) {
+    for (unsigned i = 0; i < 9; ++i) {
+      if (i < 2) {
+        mSourceBuffer->Append(mData + i, 1);
+      } else if (i == 2) {
+        mSourceBuffer->Complete(aCompletionStatus);
+      }
+
+      LexerResult result = aLexer.Lex(mIterator, mCountResumes, DoLex);
+
+      if (i >= 2) {
+        EXPECT_TRUE(result.is<TerminalState>());
+        EXPECT_EQ(aExpectedTerminalState, result.as<TerminalState>());
+      } else {
+        EXPECT_TRUE(result.is<Yield>());
+        EXPECT_EQ(Yield::NEED_MORE_DATA, result.as<Yield>());
+      }
+    }
+
+    EXPECT_EQ(2u, mCountResumes->Count());
+  }
+
+  AutoInitializeImageLib mInit;
+  const char mData[9]{1, 2, 3, 4, 5, 6, 7, 8, 9};
+  StreamingLexer<TestState> mLexer;
+  RefPtr<SourceBuffer> mSourceBuffer;
+  SourceBufferIterator mIterator;
+  RefPtr<ExpectNoResume> mExpectNoResume;
+  RefPtr<CountResumes> mCountResumes;
+};
+
+TEST_F(ImageStreamingLexer, ZeroLengthData) {
+  // Test a zero-length input.
+  mSourceBuffer->Complete(NS_OK);
+
+  LexerResult result = mLexer.Lex(mIterator, mExpectNoResume, DoLex);
+
+  EXPECT_TRUE(result.is<TerminalState>());
+  EXPECT_EQ(TerminalState::FAILURE, result.as<TerminalState>());
+}
+
+TEST_F(ImageStreamingLexer, ZeroLengthDataUnbuffered) {
+  // Test a zero-length input.
+  mSourceBuffer->Complete(NS_OK);
+
+  // Create a special StreamingLexer for this test because we want the first
+  // state to be unbuffered.
+  StreamingLexer<TestState> lexer(
+      Transition::ToUnbuffered(TestState::ONE, TestState::UNBUFFERED,
+                               sizeof(mData)),
+      Transition::TerminateFailure());
+
+  LexerResult result = lexer.Lex(mIterator, mExpectNoResume, DoLex);
+  EXPECT_TRUE(result.is<TerminalState>());
+  EXPECT_EQ(TerminalState::FAILURE, result.as<TerminalState>());
+}
+
+TEST_F(ImageStreamingLexer, StartWithTerminal) {
+  // Create a special StreamingLexer for this test because we want the first
+  // state to be a terminal state. This doesn't really make sense, but we should
+  // handle it.
+  StreamingLexer<TestState> lexer(Transition::TerminateSuccess(),
+                                  Transition::TerminateFailure());
+  LexerResult result = lexer.Lex(mIterator, mExpectNoResume, DoLex);
+  EXPECT_TRUE(result.is<TerminalState>());
+  EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+
+  mSourceBuffer->Complete(NS_OK);
+}
+
+TEST_F(ImageStreamingLexer, SingleChunk) {
+  // Test delivering all the data at once.
+  mSourceBuffer->Append(mData, sizeof(mData));
+  mSourceBuffer->Complete(NS_OK);
+
+  LexerResult result = mLexer.Lex(mIterator, mExpectNoResume, DoLex);
+
+  EXPECT_TRUE(result.is<TerminalState>());
+  EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+}
+
+TEST_F(ImageStreamingLexer, SingleChunkWithUnbuffered) {
+  Vector<char> unbufferedVector;
+
+  // Test delivering all the data at once.
+  mSourceBuffer->Append(mData, sizeof(mData));
+  mSourceBuffer->Complete(NS_OK);
+
+  LexerResult result = mLexer.Lex(
+      mIterator, mExpectNoResume,
+      [&](TestState aState, const char* aData, size_t aLength) {
+        return DoLexWithUnbuffered(aState, aData, aLength, unbufferedVector);
+      });
+
+  EXPECT_TRUE(result.is<TerminalState>());
+  EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+}
+
+TEST_F(ImageStreamingLexer, SingleChunkWithYield) {
+  // Test delivering all the data at once.
+  mSourceBuffer->Append(mData, sizeof(mData));
+  mSourceBuffer->Complete(NS_OK);
+
+  LexerResult result = mLexer.Lex(mIterator, mExpectNoResume, DoLexWithYield);
+  ASSERT_TRUE(result.is<Yield>());
+  EXPECT_EQ(Yield::OUTPUT_AVAILABLE, result.as<Yield>());
+
+  result = mLexer.Lex(mIterator, mExpectNoResume, DoLexWithYield);
+  ASSERT_TRUE(result.is<TerminalState>());
+  EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+}
+
+TEST_F(ImageStreamingLexer, ChunkPerState) {
+  // Test delivering in perfectly-sized chunks, one per state.
+  for (unsigned i = 0; i < 3; ++i) {
+    mSourceBuffer->Append(mData + 3 * i, 3);
+    LexerResult result = mLexer.Lex(mIterator, mCountResumes, DoLex);
+
+    if (i == 2) {
+      EXPECT_TRUE(result.is<TerminalState>());
+      EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+    } else {
+      EXPECT_TRUE(result.is<Yield>());
+      EXPECT_EQ(Yield::NEED_MORE_DATA, result.as<Yield>());
+    }
+  }
+
+  EXPECT_EQ(2u, mCountResumes->Count());
+  mSourceBuffer->Complete(NS_OK);
+}
+
+TEST_F(ImageStreamingLexer, ChunkPerStateWithUnbuffered) {
+  Vector<char> unbufferedVector;
+
+  // Test delivering in perfectly-sized chunks, one per state.
+  for (unsigned i = 0; i < 3; ++i) {
+    mSourceBuffer->Append(mData + 3 * i, 3);
+    LexerResult result = mLexer.Lex(
+        mIterator, mCountResumes,
+        [&](TestState aState, const char* aData, size_t aLength) {
+          return DoLexWithUnbuffered(aState, aData, aLength, unbufferedVector);
+        });
+
+    if (i == 2) {
+      EXPECT_TRUE(result.is<TerminalState>());
+      EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+    } else {
+      EXPECT_TRUE(result.is<Yield>());
+      EXPECT_EQ(Yield::NEED_MORE_DATA, result.as<Yield>());
+    }
+  }
+
+  EXPECT_EQ(2u, mCountResumes->Count());
+  mSourceBuffer->Complete(NS_OK);
+}
+
+TEST_F(ImageStreamingLexer, ChunkPerStateWithYield) {
+  // Test delivering in perfectly-sized chunks, one per state.
+  mSourceBuffer->Append(mData, 3);
+  LexerResult result = mLexer.Lex(mIterator, mCountResumes, DoLexWithYield);
+  EXPECT_TRUE(result.is<Yield>());
+  EXPECT_EQ(Yield::OUTPUT_AVAILABLE, result.as<Yield>());
+
+  result = mLexer.Lex(mIterator, mCountResumes, DoLexWithYield);
+  EXPECT_TRUE(result.is<Yield>());
+  EXPECT_EQ(Yield::NEED_MORE_DATA, result.as<Yield>());
+
+  mSourceBuffer->Append(mData + 3, 6);
+  result = mLexer.Lex(mIterator, mCountResumes, DoLexWithYield);
+  EXPECT_TRUE(result.is<TerminalState>());
+  EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+
+  EXPECT_EQ(1u, mCountResumes->Count());
+  mSourceBuffer->Complete(NS_OK);
+}
+
+TEST_F(ImageStreamingLexer, ChunkPerStateWithUnbufferedYield) {
+  size_t unbufferedCallCount = 0;
+  Vector<char> unbufferedVector;
+  auto lexerFunc = [&](TestState aState, const char* aData,
+                       size_t aLength) -> LexerTransition<TestState> {
+    switch (aState) {
+      case TestState::ONE:
+        CheckLexedData(aData, aLength, 0, 3);
+        return Transition::ToUnbuffered(TestState::TWO, TestState::UNBUFFERED,
+                                        3);
+      case TestState::TWO:
+        CheckLexedData(unbufferedVector.begin(), unbufferedVector.length(), 3,
+                       3);
+        return Transition::To(TestState::THREE, 3);
+      case TestState::THREE:
+        CheckLexedData(aData, aLength, 6, 3);
+        return Transition::TerminateSuccess();
+      case TestState::UNBUFFERED:
+        switch (unbufferedCallCount) {
+          case 0:
+            CheckLexedData(aData, aLength, 3, 3);
+            EXPECT_TRUE(unbufferedVector.append(aData, 2));
+            unbufferedCallCount++;
+
+            // Continue after yield, telling StreamingLexer we consumed 2 bytes.
+            return Transition::ContinueUnbufferedAfterYield(
+                TestState::UNBUFFERED, 2);
+
+          case 1:
+            CheckLexedData(aData, aLength, 5, 1);
+            EXPECT_TRUE(unbufferedVector.append(aData, 1));
+            unbufferedCallCount++;
+
+            // Continue after yield, telling StreamingLexer we consumed 1 byte.
+            // We should end up in the TWO state.
+            return Transition::ContinueUnbuffered(TestState::UNBUFFERED);
+        }
+        ADD_FAILURE() << "Too many invocations of TestState::UNBUFFERED";
+        return Transition::TerminateFailure();
+      default:
+        MOZ_CRASH("Unexpected or unhandled TestState");
+    }
+  };
+
+  // Test delivering in perfectly-sized chunks, one per state.
+  for (unsigned i = 0; i < 3; ++i) {
+    mSourceBuffer->Append(mData + 3 * i, 3);
+    LexerResult result = mLexer.Lex(mIterator, mCountResumes, lexerFunc);
+
+    switch (i) {
+      case 0:
+        EXPECT_TRUE(result.is<Yield>());
+        EXPECT_EQ(Yield::NEED_MORE_DATA, result.as<Yield>());
+        EXPECT_EQ(0u, unbufferedCallCount);
+        break;
+
+      case 1:
+        EXPECT_TRUE(result.is<Yield>());
+        EXPECT_EQ(Yield::OUTPUT_AVAILABLE, result.as<Yield>());
+        EXPECT_EQ(1u, unbufferedCallCount);
+
+        result = mLexer.Lex(mIterator, mCountResumes, lexerFunc);
+        EXPECT_TRUE(result.is<Yield>());
+        EXPECT_EQ(Yield::NEED_MORE_DATA, result.as<Yield>());
+        EXPECT_EQ(2u, unbufferedCallCount);
+        break;
+
+      case 2:
+        EXPECT_TRUE(result.is<TerminalState>());
+        EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+        break;
+    }
+  }
+
+  EXPECT_EQ(2u, mCountResumes->Count());
+  mSourceBuffer->Complete(NS_OK);
+
+  LexerResult result = mLexer.Lex(mIterator, mCountResumes, lexerFunc);
+  EXPECT_TRUE(result.is<TerminalState>());
+  EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+}
+
+TEST_F(ImageStreamingLexer, OneByteChunks) {
+  // Test delivering in one byte chunks.
+  for (unsigned i = 0; i < 9; ++i) {
+    mSourceBuffer->Append(mData + i, 1);
+    LexerResult result = mLexer.Lex(mIterator, mCountResumes, DoLex);
+
+    if (i == 8) {
+      EXPECT_TRUE(result.is<TerminalState>());
+      EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+    } else {
+      EXPECT_TRUE(result.is<Yield>());
+      EXPECT_EQ(Yield::NEED_MORE_DATA, result.as<Yield>());
+    }
+  }
+
+  EXPECT_EQ(8u, mCountResumes->Count());
+  mSourceBuffer->Complete(NS_OK);
+}
+
+TEST_F(ImageStreamingLexer, OneByteChunksWithUnbuffered) {
+  Vector<char> unbufferedVector;
+
+  // Test delivering in one byte chunks.
+  for (unsigned i = 0; i < 9; ++i) {
+    mSourceBuffer->Append(mData + i, 1);
+    LexerResult result = mLexer.Lex(
+        mIterator, mCountResumes,
+        [&](TestState aState, const char* aData, size_t aLength) {
+          return DoLexWithUnbuffered(aState, aData, aLength, unbufferedVector);
+        });
+
+    if (i == 8) {
+      EXPECT_TRUE(result.is<TerminalState>());
+      EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+    } else {
+      EXPECT_TRUE(result.is<Yield>());
+      EXPECT_EQ(Yield::NEED_MORE_DATA, result.as<Yield>());
+    }
+  }
+
+  EXPECT_EQ(8u, mCountResumes->Count());
+  mSourceBuffer->Complete(NS_OK);
+}
+
+TEST_F(ImageStreamingLexer, OneByteChunksWithYield) {
+  // Test delivering in one byte chunks.
+  for (unsigned i = 0; i < 9; ++i) {
+    mSourceBuffer->Append(mData + i, 1);
+    LexerResult result = mLexer.Lex(mIterator, mCountResumes, DoLexWithYield);
+
+    switch (i) {
+      case 2:
+        EXPECT_TRUE(result.is<Yield>());
+        EXPECT_EQ(Yield::OUTPUT_AVAILABLE, result.as<Yield>());
+
+        result = mLexer.Lex(mIterator, mCountResumes, DoLexWithYield);
+        EXPECT_TRUE(result.is<Yield>());
+        EXPECT_EQ(Yield::NEED_MORE_DATA, result.as<Yield>());
+        break;
+
+      case 8:
+        EXPECT_TRUE(result.is<TerminalState>());
+        EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+        break;
+
+      default:
+        EXPECT_TRUE(i < 9);
+        EXPECT_TRUE(result.is<Yield>());
+        EXPECT_EQ(Yield::NEED_MORE_DATA, result.as<Yield>());
+    }
+  }
+
+  EXPECT_EQ(8u, mCountResumes->Count());
+  mSourceBuffer->Complete(NS_OK);
+}
+
+TEST_F(ImageStreamingLexer, ZeroLengthState) {
+  mSourceBuffer->Append(mData, sizeof(mData));
+  mSourceBuffer->Complete(NS_OK);
+
+  // Create a special StreamingLexer for this test because we want the first
+  // state to be zero length.
+  StreamingLexer<TestState> lexer(Transition::To(TestState::ONE, 0),
+                                  Transition::TerminateFailure());
+
+  LexerResult result =
+      lexer.Lex(mIterator, mExpectNoResume, DoLexWithZeroLengthStates);
+
+  EXPECT_TRUE(result.is<TerminalState>());
+  EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+}
+
+TEST_F(ImageStreamingLexer, ZeroLengthStatesAtEnd) {
+  mSourceBuffer->Append(mData, sizeof(mData));
+  mSourceBuffer->Complete(NS_OK);
+
+  // Create a special StreamingLexer for this test because we want the first
+  // state to consume the full input.
+  StreamingLexer<TestState> lexer(Transition::To(TestState::ONE, 9),
+                                  Transition::TerminateFailure());
+
+  LexerResult result =
+      lexer.Lex(mIterator, mExpectNoResume, DoLexWithZeroLengthStatesAtEnd);
+
+  EXPECT_TRUE(result.is<TerminalState>());
+  EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+}
+
+TEST_F(ImageStreamingLexer, ZeroLengthStateWithYield) {
+  // Create a special StreamingLexer for this test because we want the first
+  // state to be zero length.
+  StreamingLexer<TestState> lexer(Transition::To(TestState::ONE, 0),
+                                  Transition::TerminateFailure());
+
+  mSourceBuffer->Append(mData, 3);
+  LexerResult result =
+      lexer.Lex(mIterator, mExpectNoResume, DoLexWithZeroLengthYield);
+  ASSERT_TRUE(result.is<Yield>());
+  EXPECT_EQ(Yield::OUTPUT_AVAILABLE, result.as<Yield>());
+
+  result = lexer.Lex(mIterator, mCountResumes, DoLexWithZeroLengthYield);
+  ASSERT_TRUE(result.is<Yield>());
+  EXPECT_EQ(Yield::NEED_MORE_DATA, result.as<Yield>());
+
+  mSourceBuffer->Append(mData + 3, sizeof(mData) - 3);
+  mSourceBuffer->Complete(NS_OK);
+  result = lexer.Lex(mIterator, mExpectNoResume, DoLexWithZeroLengthYield);
+  ASSERT_TRUE(result.is<TerminalState>());
+  EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+  EXPECT_EQ(1u, mCountResumes->Count());
+}
+
+TEST_F(ImageStreamingLexer, ZeroLengthStateWithUnbuffered) {
+  mSourceBuffer->Append(mData, sizeof(mData));
+  mSourceBuffer->Complete(NS_OK);
+
+  // Create a special StreamingLexer for this test because we want the first
+  // state to be both zero length and unbuffered.
+  StreamingLexer<TestState> lexer(
+      Transition::ToUnbuffered(TestState::ONE, TestState::UNBUFFERED, 0),
+      Transition::TerminateFailure());
+
+  LexerResult result = lexer.Lex(mIterator, mExpectNoResume,
+                                 DoLexWithZeroLengthStatesUnbuffered);
+
+  EXPECT_TRUE(result.is<TerminalState>());
+  EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+}
+
+TEST_F(ImageStreamingLexer, ZeroLengthStateAfterUnbuffered) {
+  mSourceBuffer->Append(mData, sizeof(mData));
+  mSourceBuffer->Complete(NS_OK);
+
+  // Create a special StreamingLexer for this test because we want the first
+  // state to be zero length.
+  StreamingLexer<TestState> lexer(Transition::To(TestState::ONE, 0),
+                                  Transition::TerminateFailure());
+
+  LexerResult result = lexer.Lex(mIterator, mExpectNoResume,
+                                 DoLexWithZeroLengthStatesAfterUnbuffered);
+
+  EXPECT_TRUE(result.is<TerminalState>());
+  EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+}
+
+TEST_F(ImageStreamingLexer, ZeroLengthStateWithUnbufferedYield) {
+  size_t unbufferedCallCount = 0;
+  auto lexerFunc = [&](TestState aState, const char* aData,
+                       size_t aLength) -> LexerTransition<TestState> {
+    switch (aState) {
+      case TestState::ONE:
+        EXPECT_EQ(0u, aLength);
+        return Transition::TerminateSuccess();
+
+      case TestState::UNBUFFERED:
+        switch (unbufferedCallCount) {
+          case 0:
+            CheckLexedData(aData, aLength, 0, 3);
+            unbufferedCallCount++;
+
+            // Continue after yield, telling StreamingLexer we consumed 0 bytes.
+            return Transition::ContinueUnbufferedAfterYield(
+                TestState::UNBUFFERED, 0);
+
+          case 1:
+            CheckLexedData(aData, aLength, 0, 3);
+            unbufferedCallCount++;
+
+            // Continue after yield, telling StreamingLexer we consumed 2 bytes.
+            return Transition::ContinueUnbufferedAfterYield(
+                TestState::UNBUFFERED, 2);
+
+          case 2:
+            EXPECT_EQ(1u, aLength);
+            CheckLexedData(aData, aLength, 2, 1);
+            unbufferedCallCount++;
+
+            // Continue after yield, telling StreamingLexer we consumed 1 bytes.
+            return Transition::ContinueUnbufferedAfterYield(
+                TestState::UNBUFFERED, 1);
+
+          case 3:
+            CheckLexedData(aData, aLength, 3, 6);
+            unbufferedCallCount++;
+
+            // Continue after yield, telling StreamingLexer we consumed 6 bytes.
+            // We should transition to TestState::ONE when we return from the
+            // yield.
+            return Transition::ContinueUnbufferedAfterYield(
+                TestState::UNBUFFERED, 6);
+        }
+
+        ADD_FAILURE() << "Too many invocations of TestState::UNBUFFERED";
+        return Transition::TerminateFailure();
+
+      default:
+        MOZ_CRASH("Unexpected or unhandled TestState");
+    }
+  };
+
+  // Create a special StreamingLexer for this test because we want the first
+  // state to be unbuffered.
+  StreamingLexer<TestState> lexer(
+      Transition::ToUnbuffered(TestState::ONE, TestState::UNBUFFERED,
+                               sizeof(mData)),
+      Transition::TerminateFailure());
+
+  mSourceBuffer->Append(mData, 3);
+  LexerResult result = lexer.Lex(mIterator, mExpectNoResume, lexerFunc);
+  ASSERT_TRUE(result.is<Yield>());
+  EXPECT_EQ(Yield::OUTPUT_AVAILABLE, result.as<Yield>());
+  EXPECT_EQ(1u, unbufferedCallCount);
+
+  result = lexer.Lex(mIterator, mExpectNoResume, lexerFunc);
+  ASSERT_TRUE(result.is<Yield>());
+  EXPECT_EQ(Yield::OUTPUT_AVAILABLE, result.as<Yield>());
+  EXPECT_EQ(2u, unbufferedCallCount);
+
+  result = lexer.Lex(mIterator, mExpectNoResume, lexerFunc);
+  ASSERT_TRUE(result.is<Yield>());
+  EXPECT_EQ(Yield::OUTPUT_AVAILABLE, result.as<Yield>());
+  EXPECT_EQ(3u, unbufferedCallCount);
+
+  result = lexer.Lex(mIterator, mCountResumes, lexerFunc);
+  ASSERT_TRUE(result.is<Yield>());
+  EXPECT_EQ(Yield::NEED_MORE_DATA, result.as<Yield>());
+  EXPECT_EQ(3u, unbufferedCallCount);
+
+  mSourceBuffer->Append(mData + 3, 6);
+  mSourceBuffer->Complete(NS_OK);
+  EXPECT_EQ(1u, mCountResumes->Count());
+  result = lexer.Lex(mIterator, mExpectNoResume, lexerFunc);
+  ASSERT_TRUE(result.is<Yield>());
+  EXPECT_EQ(Yield::OUTPUT_AVAILABLE, result.as<Yield>());
+  EXPECT_EQ(4u, unbufferedCallCount);
+
+  result = lexer.Lex(mIterator, mExpectNoResume, lexerFunc);
+  ASSERT_TRUE(result.is<TerminalState>());
+  EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+}
+
+TEST_F(ImageStreamingLexer, TerminateSuccess) {
+  mSourceBuffer->Append(mData, sizeof(mData));
+  mSourceBuffer->Complete(NS_OK);
+
+  // Test that Terminate is "sticky".
+  SourceBufferIterator iterator = mSourceBuffer->Iterator();
+  LexerResult result =
+      mLexer.Lex(iterator, mExpectNoResume,
+                 [&](TestState aState, const char* aData, size_t aLength) {
+                   EXPECT_TRUE(aState == TestState::ONE);
+                   return Transition::TerminateSuccess();
+                 });
+  EXPECT_TRUE(result.is<TerminalState>());
+  EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+
+  SourceBufferIterator iterator2 = mSourceBuffer->Iterator();
+  result = mLexer.Lex(iterator2, mExpectNoResume,
+                      [&](TestState aState, const char* aData, size_t aLength) {
+                        EXPECT_TRUE(false);  // Shouldn't get here.
+                        return Transition::TerminateFailure();
+                      });
+  EXPECT_TRUE(result.is<TerminalState>());
+  EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+}
+
+TEST_F(ImageStreamingLexer, TerminateFailure) {
+  mSourceBuffer->Append(mData, sizeof(mData));
+  mSourceBuffer->Complete(NS_OK);
+
+  // Test that Terminate is "sticky".
+  SourceBufferIterator iterator = mSourceBuffer->Iterator();
+  LexerResult result =
+      mLexer.Lex(iterator, mExpectNoResume,
+                 [&](TestState aState, const char* aData, size_t aLength) {
+                   EXPECT_TRUE(aState == TestState::ONE);
+                   return Transition::TerminateFailure();
+                 });
+  EXPECT_TRUE(result.is<TerminalState>());
+  EXPECT_EQ(TerminalState::FAILURE, result.as<TerminalState>());
+
+  SourceBufferIterator iterator2 = mSourceBuffer->Iterator();
+  result = mLexer.Lex(iterator2, mExpectNoResume,
+                      [&](TestState aState, const char* aData, size_t aLength) {
+                        EXPECT_TRUE(false);  // Shouldn't get here.
+                        return Transition::TerminateFailure();
+                      });
+  EXPECT_TRUE(result.is<TerminalState>());
+  EXPECT_EQ(TerminalState::FAILURE, result.as<TerminalState>());
+}
+
+TEST_F(ImageStreamingLexer, TerminateUnbuffered) {
+  // Test that Terminate works during an unbuffered read.
+  for (unsigned i = 0; i < 9; ++i) {
+    mSourceBuffer->Append(mData + i, 1);
+    LexerResult result =
+        mLexer.Lex(mIterator, mCountResumes, DoLexWithUnbufferedTerminate);
+
+    if (i > 2) {
+      EXPECT_TRUE(result.is<TerminalState>());
+      EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+    } else {
+      EXPECT_TRUE(result.is<Yield>());
+      EXPECT_EQ(Yield::NEED_MORE_DATA, result.as<Yield>());
+    }
+  }
+
+  // We expect 3 resumes because TestState::ONE consumes 3 bytes and then
+  // transitions to TestState::UNBUFFERED, which calls TerminateSuccess() as
+  // soon as it receives a single byte. That's four bytes total,  which are
+  // delivered one at a time, requiring 3 resumes.
+  EXPECT_EQ(3u, mCountResumes->Count());
+
+  mSourceBuffer->Complete(NS_OK);
+}
+
+TEST_F(ImageStreamingLexer, TerminateAfterYield) {
+  // Test that Terminate works after yielding.
+  for (unsigned i = 0; i < 9; ++i) {
+    mSourceBuffer->Append(mData + i, 1);
+    LexerResult result =
+        mLexer.Lex(mIterator, mCountResumes, DoLexWithTerminateAfterYield);
+
+    if (i > 2) {
+      EXPECT_TRUE(result.is<TerminalState>());
+      EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+    } else if (i == 2) {
+      EXPECT_TRUE(result.is<Yield>());
+      EXPECT_EQ(Yield::OUTPUT_AVAILABLE, result.as<Yield>());
+    } else {
+      EXPECT_TRUE(result.is<Yield>());
+      EXPECT_EQ(Yield::NEED_MORE_DATA, result.as<Yield>());
+    }
+  }
+
+  // We expect 2 resumes because TestState::ONE consumes 3 bytes and then
+  // yields. When the lexer resumes at TestState::TWO, which receives the same 3
+  // bytes, TerminateSuccess() gets called immediately.  That's three bytes
+  // total, which are delivered one at a time, requiring 2 resumes.
+  EXPECT_EQ(2u, mCountResumes->Count());
+
+  mSourceBuffer->Complete(NS_OK);
+}
+
+TEST_F(ImageStreamingLexer, SourceBufferImmediateComplete) {
+  // Test calling SourceBuffer::Complete() without appending any data. This
+  // causes the SourceBuffer to automatically have a failing completion status,
+  // no matter what you pass, so we expect TerminalState::FAILURE below.
+  mSourceBuffer->Complete(NS_OK);
+
+  LexerResult result = mLexer.Lex(mIterator, mExpectNoResume, DoLex);
+
+  EXPECT_TRUE(result.is<TerminalState>());
+  EXPECT_EQ(TerminalState::FAILURE, result.as<TerminalState>());
+}
+
+TEST_F(ImageStreamingLexer, SourceBufferTruncatedTerminalStateSuccess) {
+  // Test that using a terminal state (in this case TerminalState::SUCCESS) as a
+  // truncated state works.
+  StreamingLexer<TestState> lexer(Transition::To(TestState::ONE, 3),
+                                  Transition::TerminateSuccess());
+
+  CheckTruncatedState(lexer, TerminalState::SUCCESS);
+}
+
+TEST_F(ImageStreamingLexer, SourceBufferTruncatedTerminalStateFailure) {
+  // Test that using a terminal state (in this case TerminalState::FAILURE) as a
+  // truncated state works.
+  StreamingLexer<TestState> lexer(Transition::To(TestState::ONE, 3),
+                                  Transition::TerminateFailure());
+
+  CheckTruncatedState(lexer, TerminalState::FAILURE);
+}
+
+TEST_F(ImageStreamingLexer, SourceBufferTruncatedStateReturningSuccess) {
+  // Test that a truncated state that returns TerminalState::SUCCESS works. When
+  // |lexer| discovers that the data is truncated, it invokes the
+  // TRUNCATED_SUCCESS state, which returns TerminalState::SUCCESS.
+  // CheckTruncatedState() verifies that this happens.
+  StreamingLexer<TestState> lexer(
+      Transition::To(TestState::ONE, 3),
+      Transition::To(TestState::TRUNCATED_SUCCESS, 0));
+
+  CheckTruncatedState(lexer, TerminalState::SUCCESS);
+}
+
+TEST_F(ImageStreamingLexer, SourceBufferTruncatedStateReturningFailure) {
+  // Test that a truncated state that returns TerminalState::FAILURE works. When
+  // |lexer| discovers that the data is truncated, it invokes the
+  // TRUNCATED_FAILURE state, which returns TerminalState::FAILURE.
+  // CheckTruncatedState() verifies that this happens.
+  StreamingLexer<TestState> lexer(
+      Transition::To(TestState::ONE, 3),
+      Transition::To(TestState::TRUNCATED_FAILURE, 0));
+
+  CheckTruncatedState(lexer, TerminalState::FAILURE);
+}
+
+TEST_F(ImageStreamingLexer, SourceBufferTruncatedFailingCompleteStatus) {
+  // Test that calling SourceBuffer::Complete() with a failing status results in
+  // an immediate TerminalState::FAILURE result. (Note that |lexer|'s truncated
+  // state is TerminalState::SUCCESS, so if we ignore the failing status, the
+  // test will fail.)
+  StreamingLexer<TestState> lexer(Transition::To(TestState::ONE, 3),
+                                  Transition::TerminateSuccess());
+
+  CheckTruncatedState(lexer, TerminalState::FAILURE, NS_ERROR_FAILURE);
+}
+
+TEST_F(ImageStreamingLexer, NoSourceBufferResumable) {
+  // Test delivering in one byte chunks with no IResumable.
+  for (unsigned i = 0; i < 9; ++i) {
+    mSourceBuffer->Append(mData + i, 1);
+    LexerResult result = mLexer.Lex(mIterator, nullptr, DoLex);
+
+    if (i == 8) {
+      EXPECT_TRUE(result.is<TerminalState>());
+      EXPECT_EQ(TerminalState::SUCCESS, result.as<TerminalState>());
+    } else {
+      EXPECT_TRUE(result.is<Yield>());
+      EXPECT_EQ(Yield::NEED_MORE_DATA, result.as<Yield>());
+    }
+  }
+
+  mSourceBuffer->Complete(NS_OK);
+}