Graceful idle callback cancellation with invalid IDs.

third_party/WebKit/Source/core/dom/ScriptedIdleTaskController.cpp

 // Copyright 2015 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.
 
 #include "core/dom/ScriptedIdleTaskController.h"
 
 #include "core/dom/ExecutionContext.h"
 #include "core/dom/IdleRequestCallback.h"
 #include "core/dom/IdleRequestOptions.h"
 #include "core/inspector/InspectorTraceEvents.h"
@@ skipping 69 matching lines @@
 ScriptedIdleTaskController::~ScriptedIdleTaskController()
 {
 }
 
 DEFINE_TRACE(ScriptedIdleTaskController)
 {
     visitor->trace(m_callbacks);
     ActiveDOMObject::trace(visitor);
 }
 
+int ScriptedIdleTaskController::nextCallbackId()
+{
+    while (true) {
+        ++m_nextCallbackId;
+
+        if (!isValidCallbackId(m_nextCallbackId))
+            m_nextCallbackId = 1;
+
+        if (!m_callbacks.contains(m_nextCallbackId))
+            return m_nextCallbackId;
+    }
+}
+
 ScriptedIdleTaskController::CallbackId ScriptedIdleTaskController::registerCallback(IdleRequestCallback* callback, const IdleRequestOptions& options)
 {
-    CallbackId id = ++m_nextCallbackId;
+    CallbackId id = nextCallbackId();
     m_callbacks.set(id, callback);
     long long timeoutMillis = options.timeout();
 
     RefPtr<internal::IdleRequestCallbackWrapper> callbackWrapper = internal::IdleRequestCallbackWrapper::create(id, this);
     m_scheduler->postIdleTask(BLINK_FROM_HERE, WTF::bind<double>(&internal::IdleRequestCallbackWrapper::idleTaskFired, callbackWrapper));
     if (timeoutMillis > 0)
         m_scheduler->timerTaskRunner()->postDelayedTask(BLINK_FROM_HERE, WTF::bind(&internal::IdleRequestCallbackWrapper::timeoutFired, callbackWrapper), timeoutMillis);
     TRACE_EVENT_INSTANT1("devtools.timeline", "RequestIdleCallback", TRACE_EVENT_SCOPE_THREAD, "data", InspectorIdleCallbackRequestEvent::data(getExecutionContext(), id, timeoutMillis));
     return id;
 }
 
 void ScriptedIdleTaskController::cancelCallback(CallbackId id)
 {
     TRACE_EVENT_INSTANT1("devtools.timeline", "CancelIdleCallback", TRACE_EVENT_SCOPE_THREAD, "data", InspectorIdleCallbackCancelEvent::data(getExecutionContext(), id));
+    if (!isValidCallbackId(id))
+        return;
+
     m_callbacks.remove(id);
 }
 
 void ScriptedIdleTaskController::callbackFired(CallbackId id, double deadlineSeconds, IdleDeadline::CallbackType callbackType)
 {
     if (!m_callbacks.contains(id))
         return;
 
     if (m_suspended) {
         if (callbackType == IdleDeadline::CallbackType::CalledByTimeout) {
@@ skipping 51 matching lines @@
         runCallback(id, monotonicallyIncreasingTime(), IdleDeadline::CallbackType::CalledByTimeout);
 
     // Repost idle tasks for any remaining callbacks.
     for (auto& callback : m_callbacks) {
         RefPtr<internal::IdleRequestCallbackWrapper> callbackWrapper = internal::IdleRequestCallbackWrapper::create(callback.key, this);
         m_scheduler->postIdleTask(BLINK_FROM_HERE, WTF::bind<double>(&internal::IdleRequestCallbackWrapper::idleTaskFired, callbackWrapper));
     }
 }
 
 } // namespace blink