Initial in-process implementation of some Mojo primitives.

mojo/system/message_pipe_dispatcher_unittest.cc

Index: mojo/system/message_pipe_dispatcher_unittest.cc
diff --git a/mojo/system/message_pipe_dispatcher_unittest.cc b/mojo/system/message_pipe_dispatcher_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..acafcdaca2d9071267e8ed11fa12a6d7d1ba881e
--- /dev/null
+++ b/mojo/system/message_pipe_dispatcher_unittest.cc
@@ -0,0 +1,539 @@
+// 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.
+
+// NOTE(vtl): Some of these tests are inherently flaky (e.g., if run on a
+// heavily-loaded system). Sorry. |kEpsilonMicros| may be increased to increase
+// tolerance and reduce observed flakiness.
+
+#include "mojo/system/message_pipe_dispatcher.h"
+
+#include <string.h>
+
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_vector.h"
+#include "base/rand_util.h"
+#include "base/threading/platform_thread.h"  // For |Sleep()|.
+#include "base/threading/simple_thread.h"
+#include "base/time/time.h"
+#include "mojo/system/message_pipe.h"
+#include "mojo/system/test_utils.h"
+#include "mojo/system/waiter.h"
+#include "mojo/system/waiter_test_utils.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace mojo {
+namespace system {
+namespace {
+
+const int64_t kMicrosPerMs = 1000;
+const int64_t kEpsilonMicros = 15 * kMicrosPerMs;  // 15 ms.
+
+TEST(MessagePipeDispatcherTest, Basic) {
+  test::Stopwatch stopwatch;
+  int32_t buffer[1];
+  const uint32_t kBufferSize = static_cast<uint32_t>(sizeof(buffer));
+  uint32_t buffer_size;
+  int64_t elapsed_micros;
+
+  // Run this test both with |d_0| as port 0, |d_1| as port 1 and vice versa.
+  for (unsigned i = 0; i < 2; i++) {
+    scoped_refptr<MessagePipeDispatcher> d_0(new MessagePipeDispatcher());
+    scoped_refptr<MessagePipeDispatcher> d_1(new MessagePipeDispatcher());
+    {
+      scoped_refptr<MessagePipe> mp(new MessagePipe());
+      d_0->Init(mp, i);  // 0, 1.
+      d_1->Init(mp, i ^ 1);  // 1, 0.
+    }
+    Waiter w;
+
+    // Try adding a writable waiter when already writable.
+    w.Init();
+    EXPECT_EQ(MOJO_RESULT_ALREADY_EXISTS,
+              d_0->AddWaiter(&w, MOJO_WAIT_FLAG_WRITABLE, 0));
+    // Shouldn't need to remove the waiter (it was not added).
+
+    // Add a readable waiter to |d_0|, then make it readable (by writing to
+    // |d_1|), then wait.
+    w.Init();
+    EXPECT_EQ(MOJO_RESULT_OK,
+              d_0->AddWaiter(&w, MOJO_WAIT_FLAG_READABLE, 1));
+    buffer[0] = 123456789;
+    EXPECT_EQ(MOJO_RESULT_OK,
+              d_1->WriteMessage(buffer, kBufferSize,
+                                NULL, 0,
+                                MOJO_WRITE_MESSAGE_FLAG_NONE));
+    stopwatch.Start();
+    EXPECT_EQ(1, w.Wait(MOJO_DEADLINE_INDEFINITE));
+    elapsed_micros = stopwatch.Elapsed();
+    EXPECT_LT(elapsed_micros, kEpsilonMicros);
+    d_0->RemoveWaiter(&w);
+
+    // Try adding a readable waiter when already readable (from above).
+    w.Init();
+    EXPECT_EQ(MOJO_RESULT_ALREADY_EXISTS,
+              d_0->AddWaiter(&w, MOJO_WAIT_FLAG_READABLE, 2));
+    // Shouldn't need to remove the waiter (it was not added).
+
+    // Make |d_0| no longer readable (by reading from it).
+    buffer[0] = 0;
+    buffer_size = kBufferSize;
+    EXPECT_EQ(MOJO_RESULT_OK,
+              d_0->ReadMessage(buffer, &buffer_size,
+                               NULL, NULL,
+                               MOJO_READ_MESSAGE_FLAG_NONE));
+    EXPECT_EQ(kBufferSize, buffer_size);
+    EXPECT_EQ(123456789, buffer[0]);
+
+    // Wait for zero time for readability on |d_0| (will time out).
+    w.Init();
+    EXPECT_EQ(MOJO_RESULT_OK,
+              d_0->AddWaiter(&w, MOJO_WAIT_FLAG_READABLE, 3));
+    stopwatch.Start();
+    EXPECT_EQ(MOJO_RESULT_DEADLINE_EXCEEDED, w.Wait(0));
+    elapsed_micros = stopwatch.Elapsed();
+    EXPECT_LT(elapsed_micros, kEpsilonMicros);
+    d_0->RemoveWaiter(&w);
+
+    // Wait for non-zero, finite time for readability on |d_0| (will time out).
+    w.Init();
+    EXPECT_EQ(MOJO_RESULT_OK,
+              d_0->AddWaiter(&w, MOJO_WAIT_FLAG_READABLE, 3));
+    stopwatch.Start();
+    EXPECT_EQ(MOJO_RESULT_DEADLINE_EXCEEDED, w.Wait(2 * kEpsilonMicros));
+    elapsed_micros = stopwatch.Elapsed();
+    EXPECT_GT(elapsed_micros, (2-1) * kEpsilonMicros);
+    EXPECT_LT(elapsed_micros, (2+1) * kEpsilonMicros);
+    d_0->RemoveWaiter(&w);
+
+    EXPECT_EQ(MOJO_RESULT_OK, d_0->Close());
+    EXPECT_EQ(MOJO_RESULT_OK, d_1->Close());
+  }
+}
+
+// Test what happens when one end is closed (single-threaded test).
+TEST(MessagePipeDispatcherTest, BasicClosed) {
+  int32_t buffer[1];
+  const uint32_t kBufferSize = static_cast<uint32_t>(sizeof(buffer));
+  uint32_t buffer_size;
+
+  // Run this test both with |d_0| as port 0, |d_1| as port 1 and vice versa.
+  for (unsigned i = 0; i < 2; i++) {
+    scoped_refptr<MessagePipeDispatcher> d_0(new MessagePipeDispatcher());
+    scoped_refptr<MessagePipeDispatcher> d_1(new MessagePipeDispatcher());
+    {
+      scoped_refptr<MessagePipe> mp(new MessagePipe());
+      d_0->Init(mp, i);  // 0, 1.
+      d_1->Init(mp, i ^ 1);  // 1, 0.
+    }
+    Waiter w;
+
+    // Write (twice) to |d_1|.
+    buffer[0] = 123456789;
+    EXPECT_EQ(MOJO_RESULT_OK,
+              d_1->WriteMessage(buffer, kBufferSize,
+                                NULL, 0,
+                                MOJO_WRITE_MESSAGE_FLAG_NONE));
+    buffer[0] = 234567890;
+    EXPECT_EQ(MOJO_RESULT_OK,
+              d_1->WriteMessage(buffer, kBufferSize,
+                                NULL, 0,
+                                MOJO_WRITE_MESSAGE_FLAG_NONE));
+
+    // Try waiting for readable on |d_0|; should fail (already satisfied).
+    w.Init();
+    EXPECT_EQ(MOJO_RESULT_ALREADY_EXISTS,
+              d_0->AddWaiter(&w, MOJO_WAIT_FLAG_READABLE, 0));
+
+    // Close |d_1|.
+    EXPECT_EQ(MOJO_RESULT_OK, d_1->Close());
+
+    // Try waiting for readable on |d_0|; should fail (already satisfied).
+    w.Init();
+    EXPECT_EQ(MOJO_RESULT_ALREADY_EXISTS,
+              d_0->AddWaiter(&w, MOJO_WAIT_FLAG_READABLE, 1));
+
+    // Read from |d_0|.
+    buffer[0] = 0;
+    buffer_size = kBufferSize;
+    EXPECT_EQ(MOJO_RESULT_OK,
+              d_0->ReadMessage(buffer, &buffer_size,
+                               NULL, NULL,
+                               MOJO_READ_MESSAGE_FLAG_NONE));
+    EXPECT_EQ(kBufferSize, buffer_size);
+    EXPECT_EQ(123456789, buffer[0]);
+
+    // Try waiting for readable on |d_0|; should fail (already satisfied).
+    w.Init();
+    EXPECT_EQ(MOJO_RESULT_ALREADY_EXISTS,
+              d_0->AddWaiter(&w, MOJO_WAIT_FLAG_READABLE, 2));
+
+    // Read again from |d_0|.
+    buffer[0] = 0;
+    buffer_size = kBufferSize;
+    EXPECT_EQ(MOJO_RESULT_OK,
+              d_0->ReadMessage(buffer, &buffer_size,
+                               NULL, NULL,
+                               MOJO_READ_MESSAGE_FLAG_NONE));
+    EXPECT_EQ(kBufferSize, buffer_size);
+    EXPECT_EQ(234567890, buffer[0]);
+
+    // Try waiting for readable on |d_0|; should fail (unsatisfiable).
+    w.Init();
+    EXPECT_EQ(MOJO_RESULT_FAILED_PRECONDITION,
+              d_0->AddWaiter(&w, MOJO_WAIT_FLAG_READABLE, 3));
+
+    // Try waiting for writable on |d_0|; should fail (unsatisfiable).
+    w.Init();
+    EXPECT_EQ(MOJO_RESULT_FAILED_PRECONDITION,
+              d_0->AddWaiter(&w, MOJO_WAIT_FLAG_WRITABLE, 4));
+
+    // Try reading from |d_0|; should fail (nothing to read).
+    buffer[0] = 0;
+    buffer_size = kBufferSize;
+    EXPECT_EQ(MOJO_RESULT_NOT_FOUND,
+              d_0->ReadMessage(buffer, &buffer_size,
+                               NULL, NULL,
+                               MOJO_READ_MESSAGE_FLAG_NONE));
+
+    // Try writing to |d_0|; should fail (other end closed).
+    buffer[0] = 345678901;
+    EXPECT_EQ(MOJO_RESULT_FAILED_PRECONDITION,
+              d_0->WriteMessage(buffer, kBufferSize,
+                                NULL, 0,
+                                MOJO_WRITE_MESSAGE_FLAG_NONE));
+
+    EXPECT_EQ(MOJO_RESULT_OK, d_0->Close());
+  }
+}
+
+TEST(MessagePipeDispatcherTest, BasicThreaded) {
+  test::Stopwatch stopwatch;
+  int32_t buffer[1];
+  const uint32_t kBufferSize = static_cast<uint32_t>(sizeof(buffer));
+  uint32_t buffer_size;
+  bool did_wait;
+  MojoResult result;
+  int64_t elapsed_micros;
+
+  // Run this test both with |d_0| as port 0, |d_1| as port 1 and vice versa.
+  for (unsigned i = 0; i < 2; i++) {
+    scoped_refptr<MessagePipeDispatcher> d_0(new MessagePipeDispatcher());
+    scoped_refptr<MessagePipeDispatcher> d_1(new MessagePipeDispatcher());
+    {
+      scoped_refptr<MessagePipe> mp(new MessagePipe());
+      d_0->Init(mp, i);  // 0, 1.
+      d_1->Init(mp, i ^ 1);  // 1, 0.
+    }
+
+    // Wait for readable on |d_1|, which will become readable after some time.
+    {
+      test::WaiterThread thread(d_1,
+                                MOJO_WAIT_FLAG_READABLE,
+                                MOJO_DEADLINE_INDEFINITE,
+                                0,
+                                &did_wait, &result);
+      stopwatch.Start();
+      thread.Start();
+      base::PlatformThread::Sleep(
+          base::TimeDelta::FromMicroseconds(2 * kEpsilonMicros));
+      // Wake it up by writing to |d_0|.
+      buffer[0] = 123456789;
+      EXPECT_EQ(MOJO_RESULT_OK,
+                d_0->WriteMessage(buffer, kBufferSize,
+                                  NULL, 0,
+                                  MOJO_WRITE_MESSAGE_FLAG_NONE));
+    }  // Joins the thread.
+    elapsed_micros = stopwatch.Elapsed();
+    EXPECT_TRUE(did_wait);
+    EXPECT_EQ(0, result);
+    EXPECT_GT(elapsed_micros, (2-1) * kEpsilonMicros);
+    EXPECT_LT(elapsed_micros, (2+1) * kEpsilonMicros);
+
+    // Now |d_1| is already readable. Try waiting for it again.
+    {
+      test::WaiterThread thread(d_1,
+                                MOJO_WAIT_FLAG_READABLE,
+                                MOJO_DEADLINE_INDEFINITE,
+                                1,
+                                &did_wait, &result);
+      stopwatch.Start();
+      thread.Start();
+    }  // Joins the thread.
+    elapsed_micros = stopwatch.Elapsed();
+    EXPECT_FALSE(did_wait);
+    EXPECT_EQ(MOJO_RESULT_ALREADY_EXISTS, result);
+    EXPECT_LT(elapsed_micros, kEpsilonMicros);
+
+    // Consume what we wrote to |d_0|.
+    buffer[0] = 0;
+    buffer_size = kBufferSize;
+    EXPECT_EQ(MOJO_RESULT_OK,
+              d_1->ReadMessage(buffer, &buffer_size,
+                               NULL, NULL,
+                               MOJO_READ_MESSAGE_FLAG_NONE));
+    EXPECT_EQ(kBufferSize, buffer_size);
+    EXPECT_EQ(123456789, buffer[0]);
+
+    // Wait for readable on |d_1| and close |d_0| after some time, which should
+    // cancel that wait.
+    {
+      test::WaiterThread thread(d_1,
+                                MOJO_WAIT_FLAG_READABLE,
+                                MOJO_DEADLINE_INDEFINITE,
+                                0,
+                                &did_wait, &result);
+      stopwatch.Start();
+      thread.Start();
+      base::PlatformThread::Sleep(
+          base::TimeDelta::FromMicroseconds(2 * kEpsilonMicros));
+      EXPECT_EQ(MOJO_RESULT_OK, d_0->Close());
+    }  // Joins the thread.
+    elapsed_micros = stopwatch.Elapsed();
+    EXPECT_TRUE(did_wait);
+    EXPECT_EQ(MOJO_RESULT_FAILED_PRECONDITION, result);
+    EXPECT_GT(elapsed_micros, (2-1) * kEpsilonMicros);
+    EXPECT_LT(elapsed_micros, (2+1) * kEpsilonMicros);
+
+    EXPECT_EQ(MOJO_RESULT_OK, d_1->Close());
+  }
+
+  for (unsigned i = 0; i < 2; i++) {
+    scoped_refptr<MessagePipeDispatcher> d_0(new MessagePipeDispatcher());
+    scoped_refptr<MessagePipeDispatcher> d_1(new MessagePipeDispatcher());
+    {
+      scoped_refptr<MessagePipe> mp(new MessagePipe());
+      d_0->Init(mp, i);  // 0, 1.
+      d_1->Init(mp, i ^ 1);  // 1, 0.
+    }
+
+    // Wait for readable on |d_1| and close |d_1| after some time, which should
+    // cancel that wait.
+    {
+      test::WaiterThread thread(d_1,
+                                MOJO_WAIT_FLAG_READABLE,
+                                MOJO_DEADLINE_INDEFINITE,
+                                0,
+                                &did_wait, &result);
+      stopwatch.Start();
+      thread.Start();
+      base::PlatformThread::Sleep(
+          base::TimeDelta::FromMicroseconds(2 * kEpsilonMicros));
+      EXPECT_EQ(MOJO_RESULT_OK, d_1->Close());
+    }  // Joins the thread.
+    elapsed_micros = stopwatch.Elapsed();
+    EXPECT_TRUE(did_wait);
+    EXPECT_EQ(MOJO_RESULT_CANCELLED, result);
+    EXPECT_GT(elapsed_micros, (2-1) * kEpsilonMicros);
+    EXPECT_LT(elapsed_micros, (2+1) * kEpsilonMicros);
+
+    EXPECT_EQ(MOJO_RESULT_OK, d_0->Close());
+  }
+}
+
+// Stress test -----------------------------------------------------------------
+
+const size_t kMaxMessageSize = 2000;
+
+class WriterThread : public base::SimpleThread {
+ public:
+  // |*messages_written| and |*bytes_written| belong to the thread while it's
+  // alive.
+  WriterThread(scoped_refptr<Dispatcher> write_dispatcher,
+               size_t* messages_written, size_t* bytes_written)
+      : base::SimpleThread("writer_thread"),
+        write_dispatcher_(write_dispatcher),
+        messages_written_(messages_written),
+        bytes_written_(bytes_written) {
+    *messages_written_ = 0;
+    *bytes_written_ = 0;
+  }
+
+  virtual ~WriterThread() {
+    Join();
+  }
+
+ private:
+  virtual void Run() OVERRIDE {
+    // Make some data to write.
+    unsigned char buffer[kMaxMessageSize];
+    for (size_t i = 0; i < kMaxMessageSize; i++)
+      buffer[i] = static_cast<unsigned char>(i);
+
+    // Number of messages to write.
+    *messages_written_ = static_cast<size_t>(base::RandInt(1000, 6000));
+
+    // Write messages.
+    for (size_t i = 0; i < *messages_written_; i++) {
+      size_t bytes_to_write = base::RandInt(1,
+                                            static_cast<int>(kMaxMessageSize));
+      EXPECT_EQ(MOJO_RESULT_OK,
+                write_dispatcher_->WriteMessage(buffer, bytes_to_write,
+                                                NULL, 0,
+                                                MOJO_WRITE_MESSAGE_FLAG_NONE));
+      *bytes_written_ += bytes_to_write;
+    }
+
+    // Write one last "quit" message.
+    EXPECT_EQ(MOJO_RESULT_OK,
+              write_dispatcher_->WriteMessage("quit", 4, NULL, 0,
+                                              MOJO_WRITE_MESSAGE_FLAG_NONE));
+  }
+
+  const scoped_refptr<Dispatcher> write_dispatcher_;
+  size_t* const messages_written_;
+  size_t* const bytes_written_;
+
+  DISALLOW_COPY_AND_ASSIGN(WriterThread);
+};
+
+class ReaderThread : public base::SimpleThread {
+ public:
+  // |*messages_read| and |*bytes_read| belong to the thread while it's alive.
+  ReaderThread(scoped_refptr<Dispatcher> read_dispatcher,
+               size_t* messages_read, size_t* bytes_read)
+      : base::SimpleThread("reader_thread"),
+        read_dispatcher_(read_dispatcher),
+        messages_read_(messages_read),
+        bytes_read_(bytes_read) {
+    *messages_read_ = 0;
+    *bytes_read_ = 0;
+  }
+
+  virtual ~ReaderThread() {
+    Join();
+  }
+
+ private:
+  virtual void Run() OVERRIDE {
+    unsigned char buffer[kMaxMessageSize];
+    MojoResult result;
+    Waiter w;
+
+    // Read messages.
+    for (;;) {
+      // Wait for it to be readable.
+      w.Init();
+      result = read_dispatcher_->AddWaiter(&w, MOJO_WAIT_FLAG_READABLE, 0);
+      EXPECT_TRUE(result == MOJO_RESULT_OK ||
+                  result == MOJO_RESULT_ALREADY_EXISTS) << "result: " << result;
+      if (result == MOJO_RESULT_OK) {
+        // Actually need to wait.
+        EXPECT_EQ(0, w.Wait(MOJO_DEADLINE_INDEFINITE));
+        read_dispatcher_->RemoveWaiter(&w);
+      }
+
+      // Now, try to do the read.
+      // Clear the buffer so that we can check the result.
+      memset(buffer, 0, sizeof(buffer));
+      uint32_t buffer_size = static_cast<uint32_t>(sizeof(buffer));
+      result = read_dispatcher_->ReadMessage(buffer, &buffer_size, NULL, NULL,
+                                             MOJO_READ_MESSAGE_FLAG_NONE);
+      EXPECT_TRUE(result == MOJO_RESULT_OK ||
+                  result == MOJO_RESULT_NOT_FOUND) << "result: " << result;
+      // We're racing with others to read, so maybe we failed.
+      if (result == MOJO_RESULT_NOT_FOUND)
+        continue;  // In which case, try again.
+      // Check for quit.
+      if (buffer_size == 4 && memcmp("quit", buffer, 4) == 0)
+        return;
+      EXPECT_GE(buffer_size, 1u);
+      EXPECT_LE(buffer_size, kMaxMessageSize);
+      EXPECT_TRUE(IsValidMessage(buffer, buffer_size));
+
+      (*messages_read_)++;
+      *bytes_read_ += buffer_size;
+    }
+  }
+
+  static bool IsValidMessage(const unsigned char* buffer,
+                             uint32_t message_size) {
+    size_t i;
+    for (i = 0; i < message_size; i++) {
+      if (buffer[i] != static_cast<unsigned char>(i))
+        return false;
+    }
+    // Check that the remaining bytes weren't stomped on.
+    for (; i < kMaxMessageSize; i++) {
+      if (buffer[i] != 0)
+        return false;
+    }
+    return true;
+  }
+
+  const scoped_refptr<Dispatcher> read_dispatcher_;
+  size_t* const messages_read_;
+  size_t* const bytes_read_;
+
+  DISALLOW_COPY_AND_ASSIGN(ReaderThread);
+};
+
+TEST(MessagePipeDispatcherTest, Stress) {
+  static const size_t kNumWriters = 30;
+  static const size_t kNumReaders = kNumWriters;
+
+  scoped_refptr<MessagePipeDispatcher> d_write(new MessagePipeDispatcher());
+  scoped_refptr<MessagePipeDispatcher> d_read(new MessagePipeDispatcher());
+  {
+    scoped_refptr<MessagePipe> mp(new MessagePipe());
+    d_write->Init(mp, 0);
+    d_read->Init(mp, 1);
+  }
+
+  size_t messages_written[kNumWriters];
+  size_t bytes_written[kNumWriters];
+  size_t messages_read[kNumReaders];
+  size_t bytes_read[kNumReaders];
+  {
+    // Make writers.
+    ScopedVector<WriterThread> writers;
+    for (size_t i = 0; i < kNumWriters; i++) {
+      writers.push_back(
+          new WriterThread(d_write, &messages_written[i], &bytes_written[i]));
+    }
+
+    // Make readers.
+    ScopedVector<ReaderThread> readers;
+    for (size_t i = 0; i < kNumReaders; i++) {
+      readers.push_back(
+          new ReaderThread(d_read, &messages_read[i], &bytes_read[i]));
+    }
+
+    // Start writers.
+    for (size_t i = 0; i < kNumWriters; i++)
+      writers[i]->Start();
+
+    // Start readers.
+    for (size_t i = 0; i < kNumReaders; i++)
+      readers[i]->Start();
+
+    // TODO(vtl): Maybe I should have an event that triggers all the threads to
+    // start doing stuff for real (so that the first ones created/started aren't
+    // advantaged).
+  }  // Joins all the threads.
+
+  size_t total_messages_written = 0;
+  size_t total_bytes_written = 0;
+  for (size_t i = 0; i < kNumWriters; i++) {
+    total_messages_written += messages_written[i];
+    total_bytes_written += bytes_written[i];
+  }
+  size_t total_messages_read = 0;
+  size_t total_bytes_read = 0;
+  for (size_t i = 0; i < kNumReaders; i++) {
+    total_messages_read += messages_read[i];
+    total_bytes_read += bytes_read[i];
+    // We'd have to be really unlucky to have read no messages on a thread.
+    EXPECT_GT(messages_read[i], 0u) << "reader: " << i;
+    EXPECT_GE(bytes_read[i], messages_read[i]) << "reader: " << i;
+  }
+  EXPECT_EQ(total_messages_written, total_messages_read);
+  EXPECT_EQ(total_bytes_written, total_bytes_read);
+
+  EXPECT_EQ(MOJO_RESULT_OK, d_write->Close());
+  EXPECT_EQ(MOJO_RESULT_OK, d_read->Close());
+}
+
+}  // namespace
+}  // namespace system
+}  // namespace mojo