webkitgtk-2.16.5HEADwebkitgtk-2.16.5master

1 files changed, 143 insertions, 0 deletions

diff --git a/Source/WTF/wtf/WallTime.h b/Source/WTF/wtf/WallTime.h
new file mode 100644
index 000000000..0a85e4838
--- /dev/null
+++ b/Source/WTF/wtf/WallTime.h
@@ -0,0 +1,143 @@
+/*
+ * Copyright (C) 2016 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#ifndef WTF_WallTime_h
+#define WTF_WallTime_h
+
+#include <wtf/ClockType.h>
+#include <wtf/Seconds.h>
+
+namespace WTF {
+
+class MonotonicTime;
+class PrintStream;
+
+// The current time according to a wall clock (aka real time clock). This uses floating point
+// internally so that you can reason about infinity and other things that arise in math. It's
+// acceptable to use this to wrap NaN times, negative times, and infinite times, so long as they
+// are relative to the same clock. Specifically, WallTime should be used in agreement with the
+// principle that WallTime::now().secondsSinceEpoch().value() is the same as WTF::currentTime().
+class WallTime {
+public:
+    static const ClockType clockType = ClockType::Wall;
+    
+    // This is the epoch. So, x.secondsSinceEpoch() should be the same as x - WallTime().
+    WallTime() { }
+    
+    // Call this if you know for sure that the double represents time according to
+    // WTF::currentTime(). It must be in seconds and it must be from the same time source.
+    static WallTime fromRawSeconds(double value)
+    {
+        WallTime result;
+        result.m_value = value;
+        return result;
+    }
+    
+    WTF_EXPORT_PRIVATE static WallTime now();
+    
+    static WallTime infinity() { return fromRawSeconds(std::numeric_limits<double>::infinity()); }
+    
+    Seconds secondsSinceEpoch() const { return Seconds(m_value); }
+    
+    WallTime approximateWallTime() const { return *this; }
+    WTF_EXPORT_PRIVATE MonotonicTime approximateMonotonicTime() const;
+    
+    explicit operator bool() const { return !!m_value; }
+    
+    WallTime operator+(Seconds other) const
+    {
+        return fromRawSeconds(m_value + other.value());
+    }
+    
+    WallTime operator-(Seconds other) const
+    {
+        return fromRawSeconds(m_value - other.value());
+    }
+    
+    // Time is a scalar and scalars can be negated as this could arise from algebraic
+    // transformations. So, we allow it.
+    WallTime operator-() const
+    {
+        return fromRawSeconds(-m_value);
+    }
+    
+    WallTime& operator+=(Seconds other)
+    {
+        return *this = *this + other;
+    }
+    
+    WallTime& operator-=(Seconds other)
+    {
+        return *this = *this - other;
+    }
+    
+    Seconds operator-(WallTime other) const
+    {
+        return Seconds(m_value - other.m_value);
+    }
+    
+    bool operator==(WallTime other) const
+    {
+        return m_value == other.m_value;
+    }
+    
+    bool operator!=(WallTime other) const
+    {
+        return m_value != other.m_value;
+    }
+    
+    bool operator<(WallTime other) const
+    {
+        return m_value < other.m_value;
+    }
+    
+    bool operator>(WallTime other) const
+    {
+        return m_value > other.m_value;
+    }
+    
+    bool operator<=(WallTime other) const
+    {
+        return m_value <= other.m_value;
+    }
+    
+    bool operator>=(WallTime other) const
+    {
+        return m_value >= other.m_value;
+    }
+    
+    WTF_EXPORT_PRIVATE void dump(PrintStream&) const;
+    
+private:
+    double m_value { 0 };
+};
+
+WTF_EXPORT_PRIVATE void sleep(WallTime);
+
+} // namespace WTF
+
+using WTF::WallTime;
+
+#endif // WTF_WallTime_h