src/3rdparty/webkit/WebCore/page/DOMTimer.cpp
changeset 0 1918ee327afb
child 3 41300fa6a67c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/3rdparty/webkit/WebCore/page/DOMTimer.cpp	Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,178 @@
+/*
+ * Copyright (C) 2008 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 COMPUTER, 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 COMPUTER, 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.
+ *
+ */
+
+#include "config.h"
+#include "DOMTimer.h"
+
+#include "ScheduledAction.h"
+#include "ScriptExecutionContext.h"
+#include <wtf/HashSet.h>
+#include <wtf/StdLibExtras.h>
+
+using namespace std;
+
+namespace WebCore {
+
+static const int maxTimerNestingLevel = 5;
+static const double oneMillisecond = 0.001;
+double DOMTimer::s_minTimerInterval = 0.010; // 10 milliseconds
+
+static int timerNestingLevel = 0;
+
+DOMTimer::DOMTimer(ScriptExecutionContext* context, ScheduledAction* action, int timeout, bool singleShot)
+    : ActiveDOMObject(context, this)
+    , m_action(action)
+    , m_nextFireInterval(0)
+    , m_repeatInterval(0)
+#if !ASSERT_DISABLED
+    , m_suspended(false)
+#endif
+{
+    static int lastUsedTimeoutId = 0;
+    ++lastUsedTimeoutId;
+    // Avoid wraparound going negative on us.
+    if (lastUsedTimeoutId <= 0)
+        lastUsedTimeoutId = 1;
+    m_timeoutId = lastUsedTimeoutId;
+
+    m_nestingLevel = timerNestingLevel + 1;
+
+    scriptExecutionContext()->addTimeout(m_timeoutId, this);
+
+    double intervalMilliseconds = max(oneMillisecond, timeout * oneMillisecond);
+
+    // Use a minimum interval of 10 ms to match other browsers, but only once we've
+    // nested enough to notice that we're repeating.
+    // Faster timers might be "better", but they're incompatible.
+    if (intervalMilliseconds < s_minTimerInterval && m_nestingLevel >= maxTimerNestingLevel)
+        intervalMilliseconds = s_minTimerInterval;
+    if (singleShot)
+        startOneShot(intervalMilliseconds);
+    else
+        startRepeating(intervalMilliseconds);
+}
+
+DOMTimer::~DOMTimer()
+{
+    if (scriptExecutionContext())
+        scriptExecutionContext()->removeTimeout(m_timeoutId);
+}
+
+int DOMTimer::install(ScriptExecutionContext* context, ScheduledAction* action, int timeout, bool singleShot)
+{
+    // DOMTimer constructor links the new timer into a list of ActiveDOMObjects held by the 'context'.
+    // The timer is deleted when context is deleted (DOMTimer::contextDestroyed) or explicitly via DOMTimer::removeById(),
+    // or if it is a one-time timer and it has fired (DOMTimer::fired).
+    DOMTimer* timer = new DOMTimer(context, action, timeout, singleShot);
+    return timer->m_timeoutId;
+}
+
+void DOMTimer::removeById(ScriptExecutionContext* context, int timeoutId)
+{
+    // timeout IDs have to be positive, and 0 and -1 are unsafe to
+    // even look up since they are the empty and deleted value
+    // respectively
+    if (timeoutId <= 0)
+        return;
+    delete context->findTimeout(timeoutId);
+}
+
+void DOMTimer::fired()
+{
+    ScriptExecutionContext* context = scriptExecutionContext();
+    timerNestingLevel = m_nestingLevel;
+
+    // Simple case for non-one-shot timers.
+    if (isActive()) {
+        if (repeatInterval() && repeatInterval() < s_minTimerInterval) {
+            m_nestingLevel++;
+            if (m_nestingLevel >= maxTimerNestingLevel)
+                augmentRepeatInterval(s_minTimerInterval - repeatInterval());
+        }
+
+        // No access to member variables after this point, it can delete the timer.
+        m_action->execute(context);
+        return;
+    }
+
+    // Delete timer before executing the action for one-shot timers.
+    ScheduledAction* action = m_action.release();
+
+    // No access to member variables after this point.
+    delete this;
+
+    action->execute(context);
+    delete action;
+    timerNestingLevel = 0;
+}
+
+bool DOMTimer::hasPendingActivity() const
+{
+    return isActive();
+}
+
+void DOMTimer::contextDestroyed()
+{
+    ActiveDOMObject::contextDestroyed();
+    delete this;
+}
+
+void DOMTimer::stop()
+{
+    TimerBase::stop();
+    // Need to release JS objects potentially protected by ScheduledAction
+    // because they can form circular references back to the ScriptExecutionContext
+    // which will cause a memory leak.
+    m_action.clear();
+}
+
+void DOMTimer::suspend()
+{
+#if !ASSERT_DISABLED
+    ASSERT(!m_suspended);
+    m_suspended = true;
+#endif
+    m_nextFireInterval = nextFireInterval();
+    m_repeatInterval = repeatInterval();
+    TimerBase::stop();
+}
+
+void DOMTimer::resume()
+{
+#if !ASSERT_DISABLED
+    ASSERT(m_suspended);
+    m_suspended = false;
+#endif
+    start(m_nextFireInterval, m_repeatInterval);
+}
+
+
+bool DOMTimer::canSuspend() const
+{
+    return true;
+}
+
+} // namespace WebCore