Refactored the VS add-in

visual_studio/NativeClientVSAddIn/NativeClientVSAddIn/PluginDebuggerBase.cs

+// Copyright (c) 2012 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.
+
+namespace NativeClientVSAddIn
+{
+  using System;
+  using System.Collections.Generic;
+  using System.Windows.Forms;
+
+  using EnvDTE;
+  using EnvDTE80;
+
+  /// <summary>
+  /// This is a base class for encapsulating functionality related to attaching a debugger
+  /// to a nacl/pepper plug-in.  This base class mostly contains functionality related to finding
+  /// the plug-in.
+  /// </summary>
+  public class PluginDebuggerBase : IDisposable
+  {
+    /// <summary>
+    /// This is the initial number of milliseconds to wait between
+    /// checking for plug-in processes to attach the debugger to.
+    /// </summary>
+    private const int InitialPluginCheckFrequency = 1000;
+
+    /// <summary>
+    /// After a plug-in has been found, we slow the frequency of checking
+    /// for new ones. This value is in milliseconds.
+    /// </summary>
+    private const int RelaxedPluginCheckFrequency = 5000;
+
+    /// <summary>
+    /// Timer object that periodically calls a function to look for the plug-in process to debug.
+    /// </summary>
+    private Timer pluginFinderTimer_;
+
+    /// <summary>
+    /// List of process IDs which we should not attempt to attach the debugger to. Mainly this
+    /// list contains process IDs of processes we have already attached to.
+    /// </summary>
+    private List<uint> pluginFinderForbiddenPids_;
+
+    /// <summary>
+    /// Process searcher class which allows us to query the system for running processes.
+    /// </summary>
+    private ProcessSearcher processSearcher_;
+
+    /// <summary>
+    /// The main process of chrome that was started by Visual Studio during debugging.
+    /// </summary>
+    private System.Diagnostics.Process debuggedChromeMainProcess_;
+
+    /// <summary>
+    /// Constructs the PluginDebuggerHelper.
+    /// </summary>
+    /// <param name="dte">Automation object from Visual Studio.</param>
+    /// <param name="properties">PropertyManager set to a valid project/platform.</param>
+    protected PluginDebuggerBase(DTE2 dte, PropertyManager properties)
+    {
+      if (dte == null)
+      {
+        throw new ArgumentNullException("dte");
+      }
+
+      if (properties == null)
+      {
+        throw new ArgumentNullException("properties");
+      }
+
+      Dte = dte;
+
+      // Every second, check for a new instance of the plug-in to attach to.
+      // Note that although the timer itself runs on a separate thread, the event
+      // is fired from the main UI thread during message processing, thus we do not
+      // need to worry about threading issues.
+      pluginFinderTimer_ = new Timer();
+      pluginFinderTimer_.Tick += new EventHandler(FindAndAttachToPlugin);
+      pluginFinderForbiddenPids_ = new List<uint>();
+      processSearcher_ = new ProcessSearcher();
+
+      pluginFinderTimer_.Interval = InitialPluginCheckFrequency;
+      pluginFinderTimer_.Start();
+    }
+
+    /// <summary>
+    /// Finalizer. Should clean up unmanaged resources. Should not be overriden in derived classes.
+    /// </summary>
+    ~PluginDebuggerBase()
+    {
+      Dispose(false);
+    }
+
+    /// <summary>
+    /// An event indicating a target plug-in was found on the system.
+    /// </summary>
+    public event EventHandler<PluginFoundEventArgs> PluginFoundEvent;
+
+    /// <summary>
+    /// Gets or sets a value indicating whether this object has been disposed of already.
+    /// </summary>
+    protected bool Disposed { get; set; }
+
+    /// <summary>
+    /// Gets or sets the main visual studio object.
+    /// </summary>
+    protected DTE2 Dte { get; set; }
+
+    /// <summary>
+    /// Disposes the object when called by user code (not directly by garbage collector).
+    /// </summary>
+    public void Dispose()
+    {
+      Dispose(true);
+      GC.SuppressFinalize(this);
+    }
+
+    /// <summary>
+    /// This is called periodically by the Visual Studio UI thread to look for our plug-in process
+    /// and attach the debugger to it.  The call is triggered by the pluginFinderTimer_ object.
+    /// </summary>
+    /// <param name="unused">The parameter is not used.</param>
+    /// <param name="unused1">The parameter is not used.</param>
+    public void FindAndAttachToPlugin(object unused, EventArgs unused1)
+    {
+      // This function is called by the main Visual Studio event loop and we may have put the event
+      // on the queue just before disposing it meaning this could be called after we've disposed.
+      if (Disposed)
+      {
+        return;
+      }
+
+      StringComparison ignoreCase = StringComparison.InvariantCultureIgnoreCase;
+
+      // Set the main chrome process that was started by visual studio.  If it's not chrome
+      // or not found then we have no business attaching to any plug-ins so return.
+      if (debuggedChromeMainProcess_ == null)
+      {
+        foreach (Process proc in Dte.Debugger.DebuggedProcesses)
+        {
+          if (proc.Name.EndsWith(Strings.ChromeProcessName, ignoreCase))
+          {
+            debuggedChromeMainProcess_ = System.Diagnostics.Process.GetProcessById(proc.ProcessID);
+            break;
+          }
+        }
+
+        return;
+      }
+
+      // Get the list of all descendants of the main chrome process.
+      uint mainChromeProcId = (uint)debuggedChromeMainProcess_.Id;
+      List<ProcessInfo> chromeDescendants = processSearcher_.GetDescendants(mainChromeProcId);
+      string mainChromeFlags = chromeDescendants.Find(p => p.ID == mainChromeProcId).CommandLine;
+
+      // From the list of descendants, find the plug-in by it's command line arguments and
+      // process name as well as not being attached to already.
+      List<ProcessInfo> plugins = chromeDescendants.FindAll(p =>
+          IsPluginProcess(p, mainChromeFlags) && !pluginFinderForbiddenPids_.Contains(p.ID));
+
+      // Attach to all plug-ins that we found.
+      foreach (ProcessInfo process in plugins)
+      {
+        // If we are attaching to a plug-in, add it to the forbidden list to ensure we
+        // don't try to attach again later.
+        pluginFinderForbiddenPids_.Add(process.ID);
+        PluginFoundEvent.Invoke(this, new PluginFoundEventArgs(process.ID));
+
+        // Slow down the frequency of checks for new plugins.
+        pluginFinderTimer_.Interval = RelaxedPluginCheckFrequency;
+      }
+    }
+
+    /// <summary>
+    /// Disposes the object. If disposing is false then this has been called by garbage collection,
+    /// and we shouldn't reference managed objects.
+    /// </summary>
+    /// <param name="disposing">True if user call to Dispose, false if garbase collection.</param>
+    protected virtual void Dispose(bool disposing)
+    {
+      if (!Disposed && disposing)
+      {
+        pluginFinderTimer_.Stop();
+      }
+      
+      Disposed = true;
+    }
+
+    /// <summary>
+    /// Called to check if a process is a valid plugin to attach to.
+    /// </summary>
+    /// <param name="proc">Contains information about the process in question.</param>
+    /// <param name="mainChromeFlags">Flags on the main Chrome process.</param>
+    /// <returns>True if we should attach to the process.</returns>
+    protected virtual bool IsPluginProcess(ProcessInfo proc, string mainChromeFlags)
+    {
+      throw new InvalidOperationException();
+    }
+
+    /// <summary>
+    /// The event arguments when a plug-in is found.
+    /// </summary>
+    public class PluginFoundEventArgs : EventArgs
+    {
+      /// <summary>
+      /// Construct the PluginFoundEventArgs.
+      /// </summary>
+      /// <param name="pid">Process ID of the found plug-in.</param>
+      public PluginFoundEventArgs(uint pid)
+      {
+        this.ProcessID = pid;
+      }
+
+      /// <summary>
+      /// Gets or sets process ID of the found plug-in.
+      /// </summary>
+      public uint ProcessID { get; set; }
+    }
+  }
+}