Cleanup Semaphore class.

test/cctest/test-semaphore.cc

+// Copyright 2013 the V8 project authors. All rights reserved.
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+//
+// Tests of the TokenLock class from lock.h

[Michael Starzinger, 2013/09/02 11:45:31]

nit: This comment seems outdated, let's drop it.

[Benedikt Meurer, 2013/09/02 12:04:31]

Done.

+
+#include <stdlib.h>
+
+#include "v8.h"
+
+#include "platform.h"
+#include "cctest.h"
+
+
+using namespace ::v8::internal;
+
+
+TEST(WaitAndSignal) {
+  class WaitAndSignalThread V8_FINAL : public Thread {
+   public:
+    explicit WaitAndSignalThread(Semaphore* semaphore)
+        : Thread("WaitAndSignalThread"), semaphore_(semaphore) {}
+    virtual ~WaitAndSignalThread() {}
+
+    virtual void Run() V8_OVERRIDE {
+      for (int n = 0; n < 1000; ++n) {
+        semaphore_->Wait();
+        bool result = semaphore_->WaitFor(TimeDelta::FromMicroseconds(1));
+        ASSERT(!result);
+        USE(result);
+        semaphore_->Signal();
+      }
+    }
+
+   private:
+    Semaphore* semaphore_;
+  };
+
+  Semaphore semaphore(0);
+  WaitAndSignalThread t1(&semaphore);
+  WaitAndSignalThread t2(&semaphore);
+
+  t1.Start();
+  t2.Start();
+
+  // Make something available.
+  semaphore.Signal();
+
+  t1.Join();
+  t2.Join();
+
+  semaphore.Wait();
+
+  bool result = semaphore.WaitFor(TimeDelta::FromMicroseconds(1));
+  ASSERT(!result);
+  USE(result);
+}
+
+
+TEST(WaitFor) {
+  bool ok;
+  Semaphore semaphore(0);
+
+  // Semaphore not signalled - timeout.
+  ok = semaphore.WaitFor(TimeDelta::FromMicroseconds(0));
+  CHECK(!ok);
+  ok = semaphore.WaitFor(TimeDelta::FromMicroseconds(100));
+  CHECK(!ok);
+  ok = semaphore.WaitFor(TimeDelta::FromMicroseconds(1000));
+  CHECK(!ok);
+
+  // Semaphore signalled - no timeout.
+  semaphore.Signal();
+  ok = semaphore.WaitFor(TimeDelta::FromMicroseconds(0));
+  semaphore.Signal();
+  ok = semaphore.WaitFor(TimeDelta::FromMicroseconds(100));
+  semaphore.Signal();
+  ok = semaphore.WaitFor(TimeDelta::FromMicroseconds(1000));
+  CHECK(ok);
+}
+
+
+static const char alphabet[] = "XKOAD";
+static const int kAlphabetSize = sizeof(alphabet) - 1;
+static const int kBufferSize = 4096;  // GCD(buffer size, alphabet size) = 1
+static char buffer[kBufferSize];
+static const int kDataSize = kBufferSize * kAlphabetSize * 10;
+
+static Semaphore free_space(kBufferSize);
+static Semaphore used_space(0);
+
+
+class ProducerThread V8_FINAL : public Thread {
+  public:
+  ProducerThread() : Thread("ProducerThread") {}
+  virtual ~ProducerThread() {}
+
+  virtual void Run() V8_OVERRIDE {
+    for (int n = 0; n < kDataSize; ++n) {
+      free_space.Wait();
+      buffer[n % kBufferSize] = alphabet[n % kAlphabetSize];
+      used_space.Signal();
+    }
+  }
+};
+
+
+class ConsumerThread V8_FINAL : public Thread {
+  public:
+  ConsumerThread() : Thread("ConsumerThread") {}
+  virtual ~ConsumerThread() {}
+
+  virtual void Run() V8_OVERRIDE {
+    for (int n = 0; n < kDataSize; ++n) {
+      used_space.Wait();
+      ASSERT_EQ(static_cast<int>(alphabet[n % kAlphabetSize]),
+                static_cast<int>(buffer[n % kBufferSize]));
+      free_space.Signal();
+    }
+  }
+};
+
+
+TEST(ProducerConsumer) {
+  ProducerThread producer_thread;
+  ConsumerThread consumer_thread;
+  producer_thread.Start();
+  consumer_thread.Start();
+  producer_thread.Join();
+  consumer_thread.Join();
+}