// Copyright © 2015 The CefSharp Authors. All rights reserved.
|
//
|
// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
|
|
using System;
|
using System.Threading;
|
using System.Threading.Tasks;
|
using CefSharp.Internals.Tasks;
|
|
namespace CefSharp.Internals
|
{
|
/// <summary>
|
/// MethodRunnerQueue - Async Javascript Binding methods are run
|
/// on the ThreadPool sequentially
|
/// </summary>
|
public sealed class MethodRunnerQueue : IMethodRunnerQueue
|
{
|
//Limit to 1 task per methodRunnerQueue
|
//https://social.msdn.microsoft.com/Forums/vstudio/en-US/d0bcb415-fb1e-42e4-90f8-c43a088537fb/aborting-a-long-running-task-in-tpl?forum=parallelextensions
|
private readonly LimitedConcurrencyLevelTaskScheduler taskScheduler = new LimitedConcurrencyLevelTaskScheduler(1);
|
private readonly IJavascriptObjectRepositoryInternal repository;
|
private readonly CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();
|
|
/// <inheritdoc/>
|
public event EventHandler<MethodInvocationCompleteArgs> MethodInvocationComplete;
|
|
/// <summary>
|
/// Default constructor
|
/// </summary>
|
/// <param name="repository">javascript object repository</param>
|
public MethodRunnerQueue(IJavascriptObjectRepositoryInternal repository)
|
{
|
this.repository = repository;
|
}
|
|
/// <inheritdoc/>
|
public void Dispose()
|
{
|
//Cancel all tasks associated with this MethoRunnerQueue
|
cancellationTokenSource.Cancel();
|
}
|
|
/// <inheritdoc/>
|
public void Enqueue(MethodInvocation methodInvocation)
|
{
|
if(cancellationTokenSource.IsCancellationRequested)
|
{
|
return;
|
}
|
|
Task.Factory.StartNew(() =>
|
{
|
if (cancellationTokenSource.IsCancellationRequested)
|
{
|
return;
|
}
|
|
var result = ExecuteMethodInvocation(methodInvocation);
|
|
var handler = MethodInvocationComplete;
|
if (!cancellationTokenSource.Token.IsCancellationRequested && handler != null)
|
{
|
handler(this, new MethodInvocationCompleteArgs(result));
|
}
|
}, cancellationTokenSource.Token, TaskCreationOptions.HideScheduler, taskScheduler);
|
}
|
|
private MethodInvocationResult ExecuteMethodInvocation(MethodInvocation methodInvocation)
|
{
|
object returnValue = null;
|
string exception;
|
var success = false;
|
var nameConverter = repository.NameConverter;
|
|
//make sure we don't throw exceptions in the executor task
|
try
|
{
|
var result = repository.TryCallMethod(methodInvocation.ObjectId, methodInvocation.MethodName, methodInvocation.Parameters.ToArray());
|
success = result.Success;
|
returnValue = result.ReturnValue;
|
exception = result.Exception;
|
|
//We don't support Tasks by default
|
if (success && returnValue != null && (typeof(Task).IsAssignableFrom(returnValue.GetType())))
|
{
|
//Use StringBuilder to improve the formatting/readability of the error message
|
//I'm sure there's a better way I just cannot remember of the top of my head so going
|
//with this for now, as it's only for error scenaiors I'm not concerned about performance.
|
var builder = new System.Text.StringBuilder();
|
builder.AppendLine("Your method returned a Task which is not supported by default you must set CefSharpSettings.ConcurrentTaskExecution = true; before creating your first ChromiumWebBrowser instance.");
|
builder.AppendLine("This will likely change to the default at some point in the near future, subscribe to the issue link below to be notified of any changes.");
|
builder.AppendLine("See https://github.com/cefsharp/CefSharp/issues/2758 for more details, please report any issues you have there, make sure you have an example ready that reproduces your problem.");
|
|
success = false;
|
result = null;
|
exception = builder.ToString();
|
}
|
}
|
catch (Exception e)
|
{
|
exception = e.Message;
|
}
|
|
return new MethodInvocationResult
|
{
|
BrowserId = methodInvocation.BrowserId,
|
CallbackId = methodInvocation.CallbackId,
|
FrameId = methodInvocation.FrameId,
|
Message = exception,
|
Result = returnValue,
|
Success = success,
|
NameConverter = nameConverter
|
};
|
}
|
}
|
}
|
