[NaCl SDK} Add EventListener and EventEmitter to support epoll.

native_client_sdk/src/libraries/nacl_io_test/event_test.cc

+/* 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.
+ */

[Sam Clegg, 2013/07/17 17:34:56]

C++ comment

[Sam Clegg, 2013/07/17 17:34:56]

C++ comment

+
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+
+#include "gtest/gtest.h"
+
+#include "nacl_io/event_emitter.h"
+#include "nacl_io/event_listener.h"
+
+
+class EventEmitterTester : public EventEmitter {
+ public:
+  EventEmitterTester() : event_status_(0), event_cnt_(0) {}
+
+  void SetEventStatus(uint32_t bits) { event_status_ = bits; }
+  uint32_t GetEventStatus() { return event_status_; }
+
+  int GetType() { return S_IFSOCK; }
+
+  int NumEvents() { return event_cnt_; }
+
+ public:
+  // Make this function public for testing
+  void RaiseEvent(uint32_t events) {

[binji, 2013/07/17 22:23:20]

just use "using EventEmitter::RaiseEvent;"

[noelallen1, 2013/07/18 22:18:16]

I think the style is a bit ambiguous here.   Using namespace is frowned on. 
Using directive is acceptable, but I'm not sure it's preffered to explicitly
chaining the parent here.

+    EventEmitter::RaiseEvent(events);
+  }
+
+    // Called after registering locally, but while lock is still held.
+  void ChainRegister(const ScopedEventInfo& event) {
+    event_cnt_++;
+  }
+
+  // Called before unregistering locally, but while lock is still held.
+  void ChainUnregister(const ScopedEventInfo& event) {
+    event_cnt_--;
+  }
+
+ protected:
+  uint32_t event_status_;
+  uint32_t event_cnt_;
+};
+
+
+const int MAX_EVENTS = 8;
+const int FD_EMITTER = 5;
+const int DUP_EMITTER = 6;
+
+const uint32_t SIG_FILTER = 2;
+const uint64_t SIG_DATA = 1;
+
+TEST(EventTest, EmitterBasic) {
+  ScopedRef<EventEmitterTester> emitter(new EventEmitterTester());
+  ScopedRef<EventEmitter> null_emitter;
+  ScopedEventInfo null_info;
+
+  ScopedEventListener listener(new EventListener);
+
+  // Verify construction
+  EXPECT_EQ(0, emitter->NumEvents());
+  EXPECT_EQ(0, emitter->GetEventStatus());
+
+  // Verify status
+  emitter->SetEventStatus(1);
+  EXPECT_EQ(1, emitter->GetEventStatus());
+
+  // Fail to update an FD not in the set
+  EXPECT_EQ(ENOENT, listener->Update(FD_EMITTER, SIG_FILTER, SIG_DATA));
+  EXPECT_EQ(ENOENT, listener->Free(FD_EMITTER));
+
+  // Set the emitter filter and data
+  EXPECT_EQ(0, listener->Track(FD_EMITTER, emitter, SIG_FILTER, SIG_DATA));
+  EXPECT_EQ(1, emitter->NumEvents());
+
+  // Update an existing FD
+  EXPECT_EQ(0, listener->Update(FD_EMITTER, SIG_FILTER, SIG_DATA));

[binji, 2013/07/17 22:23:20]

test that the values change?

[noelallen1, 2013/07/18 22:18:16]

Done.

+
+  // Fail to add the same FD
+  EXPECT_EQ(EEXIST, listener->Track(FD_EMITTER, emitter, SIG_FILTER, SIG_DATA));
+  EXPECT_EQ(1, emitter->NumEvents());
+
+  int event_cnt = 0;
+  EventData ev[MAX_EVENTS];
+
+  // Do not allow a wait with no events
+  EXPECT_EQ(EINVAL, listener->Wait(ev, 0, 0, &event_cnt));

[binji, 2013/07/17 22:23:20]

might be nice to mention that these are all without timeouts. Maybe just as a
new test?

[noelallen1, 2013/07/18 22:18:16]

I've replaced the const values with const variables that are elf documenting.

+
+  // Do not allow a wait with no events
+  EXPECT_EQ(EINVAL, listener->Wait(ev, -1, 0, &event_cnt));
+
+  // Do not allow a wait with a NULL EventData pointer
+  EXPECT_EQ(EFAULT, listener->Wait(NULL, MAX_EVENTS, 0, &event_cnt));
+
+  // Return unsignaled
+  memset(ev, 0, sizeof(ev));
+  event_cnt = 100;
+  emitter->SetEventStatus(0);
+  EXPECT_EQ(0, listener->Wait(ev, MAX_EVENTS, 0, &event_cnt));
+  EXPECT_EQ(0, event_cnt);
+
+  // Return with one event signaled
+  event_cnt = 100;
+  emitter->SetEventStatus(3);

[binji, 2013/07/17 22:23:20]

SIG_FILTER?

Though maybe an explicit test that events are filtered: e.g.

SetEventStatus(1) -> no events signalled
SetEventStatus(3) -> one event signalled

+  EXPECT_EQ(0, listener->Wait(ev, MAX_EVENTS, 0, &event_cnt));
+  EXPECT_EQ(1, event_cnt);
+  EXPECT_EQ(SIG_DATA, ev[0].data);
+  EXPECT_EQ(SIG_FILTER, ev[0].events);
+
+  // Support adding a DUP
+  EXPECT_EQ(0, listener->Track(DUP_EMITTER, emitter, SIG_FILTER, SIG_DATA));
+  EXPECT_EQ(2, emitter->NumEvents());
+
+  // Return unsignaled
+  memset(ev, 0, sizeof(ev));
+  emitter->SetEventStatus(0);
+  event_cnt = 100;
+  EXPECT_EQ(0, listener->Wait(ev, MAX_EVENTS, 0, &event_cnt));
+  EXPECT_EQ(0, event_cnt);
+
+  // Return with two event signaled
+  emitter->SetEventStatus(3);
+  event_cnt = 100;
+  EXPECT_EQ(0, listener->Wait(ev, MAX_EVENTS, 0, &event_cnt));
+  EXPECT_EQ(2, event_cnt);
+  EXPECT_EQ(SIG_DATA, ev[0].data);
+  EXPECT_EQ(SIG_FILTER, ev[0].events);
+  EXPECT_EQ(SIG_DATA, ev[1].data);
+  EXPECT_EQ(SIG_FILTER, ev[1].events);

[Sam Clegg, 2013/07/17 17:34:56]

There are rather a lot of assertions in this one test.  Can it be split up into
chunks with useful names?

[noelallen1, 2013/07/17 21:00:18]

I'm verifying the behavior of only a single call:
   listener->Wait(ev, MAX_EVENTS, 0, &event_cnt);

The event_cnt is expected, and the data in ev[0], and ev[1] is expected.

+}
+
+long Duration(struct timeval* start, struct timeval* end) {
+  if (start->tv_usec > end->tv_usec) {
+    end->tv_sec -= 1;
+    end->tv_usec += 1000000;
+  }
+  long cur_time = 1000 * (end->tv_sec - start->tv_sec);
+  cur_time += (end->tv_usec - start->tv_usec) / 1000;
+  return cur_time;
+}
+
+
+// Run a timed wait, and return the average of 8 iterations to reduce
+// chance of false negative on outlier.
+const int TRIES_TO_AVERAGE = 8;
+bool TimedListen(ScopedEventListener& listen,
+                 EventData* ev,
+                 int ev_max,
+                 int ev_expect,
+                 int ms_wait,
+                 long* duration) {
+
+  struct timeval start;
+  struct timeval end;
+  long total_time = 0;
+
+  for (int a=0; a < TRIES_TO_AVERAGE; a++) {
+    gettimeofday(&start, NULL);
+
+    int signaled;
+
+    EXPECT_EQ(0, listen->Wait(ev, ev_max, ms_wait, &signaled));
+    EXPECT_EQ(signaled, ev_expect);
+
+    if (signaled != ev_expect) {
+      return false;
+    }
+
+    gettimeofday(&end, NULL);
+
+    long cur_time = Duration(&start, &end);
+    total_time += cur_time;
+  }
+
+  *duration = total_time / TRIES_TO_AVERAGE;
+  return true;
+}
+
+
+// NOTE:  These timing tests are potentially flacky, the real test is

[binji, 2013/07/17 22:23:20]

sp: flaky

[noelallen1, 2013/07/18 22:18:16]

Done.

+// for the zero timeout should be, has the ConditionVariable been waited on?
+// Once we provide a debuggable SimpleCond and SimpleLock we can actually test
+// the correct thing.
+
+// MAX_MS_TIMEOUT
+const int NO_MS_TIMEOUT = 0;
+
+// Wait at most .5 seconds
+const int MAX_MS_TIMEOUT = 500;
+
+// Wait forever
+const int NEVER_TIMEOUT = -1;
+
+// However, normal schedule would expect us to see < 10ms, but we'll
+// use a much bigger number (yet smaller than the MAX_MS_TIMEOUT).
+const int MAX_MS_EXPECTED = MAX_MS_TIMEOUT / 2;
+
+const int EXPECT_ONE_EVENT = 1;
+const int EXPECT_NO_EVENT = 0;
+
+TEST(EventTest, EmitterTimeout) {
+  ScopedRef<EventEmitterTester> emitter(new EventEmitterTester());
+  ScopedEventListener listener(new EventListener());
+  long duration;
+
+  EventData ev[MAX_EVENTS];
+  memset(ev, 0, sizeof(ev));
+  EXPECT_EQ(0, listener->Track(FD_EMITTER, emitter, SIG_FILTER, SIG_DATA));
+
+  // Return immediately when emitter is signaled, with no timeout
+  emitter->SetEventStatus(SIG_FILTER);
+  memset(ev, 0, sizeof(ev));
+  EXPECT_TRUE(TimedListen(listener, ev, MAX_EVENTS, EXPECT_ONE_EVENT,
+                          NO_MS_TIMEOUT, &duration));
+  EXPECT_EQ(SIG_DATA, ev[0].data);
+  EXPECT_EQ(SIG_FILTER, ev[0].events);
+  EXPECT_EQ(0, duration);
+
+  // Return immediately when emitter is signaled, even with timeout
+  emitter->SetEventStatus(SIG_FILTER);
+  memset(ev, 0, sizeof(ev));
+  EXPECT_TRUE(TimedListen(listener, ev, MAX_EVENTS, EXPECT_ONE_EVENT,
+                          MAX_MS_TIMEOUT, &duration));
+  EXPECT_EQ(SIG_DATA, ev[0].data);
+  EXPECT_EQ(SIG_FILTER, ev[0].events);
+  EXPECT_GT(25, duration);

[binji, 2013/07/17 22:23:20]

const for 25 too?

[noelallen1, 2013/07/18 22:18:16]

Done.

+
+  // Return immediately when emitter is signaled, when block forever
+  emitter->SetEventStatus(SIG_FILTER);
+  memset(ev, 0, sizeof(ev));
+  EXPECT_TRUE(TimedListen(listener, ev, MAX_EVENTS, EXPECT_ONE_EVENT,
+                          NEVER_TIMEOUT, &duration));
+  EXPECT_EQ(SIG_DATA, ev[0].data);
+  EXPECT_EQ(SIG_FILTER, ev[0].events);
+  EXPECT_GT(25, duration);
+
+  // Timeout immediately when emitter is not signaled
+  emitter->SetEventStatus(0);
+  memset(ev, 0, sizeof(ev));
+  EXPECT_TRUE(TimedListen(listener, ev, MAX_EVENTS, EXPECT_NO_EVENT,
+                          NO_MS_TIMEOUT, &duration));
+  EXPECT_EQ(0, ev[0].data);
+  EXPECT_EQ(0, ev[0].events);
+  EXPECT_EQ(0, duration);
+
+  // Return after timeout when emitter not signaled
+  emitter->SetEventStatus(0);
+  memset(ev, 0, sizeof(ev));
+  EXPECT_TRUE(TimedListen(listener, ev, MAX_EVENTS, EXPECT_NO_EVENT,
+                          MAX_MS_TIMEOUT, &duration));
+  EXPECT_EQ(0, ev[0].data);
+  EXPECT_EQ(0, ev[0].events);
+  EXPECT_LT(MAX_MS_TIMEOUT - 1, duration);
+  EXPECT_GT(MAX_MS_TIMEOUT + MAX_MS_TIMEOUT, duration);

[Sam Clegg, 2013/07/17 17:34:56]

ditto.

[noelallen1, 2013/07/17 21:00:18]

Done.

+}
+
+struct SignalInfo {
+  EventEmitterTester* em;
+  unsigned int ms_wait;
+  uint32_t events;
+};
+
+void *SignalEmitter(void *ptr) {
+  SignalInfo* info = (SignalInfo*) ptr;
+  struct timespec ts;
+  ts.tv_sec = 0;
+  ts.tv_nsec = info->ms_wait * 1000000;
+
+  nanosleep(&ts, NULL);
+
+  info->em->RaiseEvent(info->events);
+  return NULL;
+}
+
+const int VERY_LONG_WAIT = 1000;
+TEST(EventTest, EmitterSignalling) {
+  ScopedRef<EventEmitterTester> emitter(new EventEmitterTester());
+  ScopedEventListener listener(new EventListener);
+
+  SignalInfo siginfo;
+  struct timeval start;
+  struct timeval end;
+  long duration;
+
+  EventData ev[MAX_EVENTS];
+  memset(ev, 0, sizeof(ev));
+  EXPECT_EQ(0, listener->Track(FD_EMITTER, emitter, SIG_FILTER, SIG_DATA));
+
+  siginfo.em = emitter.get();
+  siginfo.ms_wait = VERY_LONG_WAIT / 4;
+  siginfo.events = SIG_FILTER;
+
+  pthread_t tid;
+  pthread_create(&tid, NULL, SignalEmitter, &siginfo);
+
+  gettimeofday(&start, NULL);
+  int cnt = 0;
+  EXPECT_EQ(0, listener->Wait(ev, MAX_EVENTS, VERY_LONG_WAIT, &cnt));
+  EXPECT_EQ(1, cnt);
+  gettimeofday(&end, NULL);
+
+  duration = Duration(&start, &end);
+  EXPECT_GT(VERY_LONG_WAIT, duration);
+  EXPECT_LT((VERY_LONG_WAIT / 4) - 1, duration);
+  EXPECT_EQ(SIG_DATA, ev[0].data);
+  EXPECT_EQ(SIG_FILTER, ev[0].events);
+}