DevTools - Add GetNextDevToolsMessageId to IBrowserHost (#3774)

Author: campersau

CefSharp.Core.Runtime/Internals/CefBrowserHostWrapper.cpp

@@ -270,6 +270,11 @@ IRegistration^ CefBrowserHostWrapper::AddDevToolsMessageObserver(IDevToolsMessag
     return gcnew CefRegistrationWrapper(registration);
 }
 
+int CefBrowserHostWrapper::GetNextDevToolsMessageId()
+{
+    return Interlocked::Increment(_lastDevToolsMessageId);
+}
+
 void CefBrowserHostWrapper::AddWordToDictionary(String^ word)
 {
     ThrowIfDisposed();

CefSharp.Core.Runtime/Internals/CefBrowserHostWrapper.h

@@ -21,6 +21,7 @@ namespace CefSharp
         {
         private:
             MCefRefPtr<CefBrowserHost> _browserHost;
+            int _lastDevToolsMessageId = 0;
 
             double GetZoomLevelOnUI();
 
@@ -75,6 +76,7 @@ namespace CefSharp
             virtual int ExecuteDevToolsMethod(int messageId, String^ method, String^ paramsAsJson);
             virtual int ExecuteDevToolsMethod(int messageId, String^ method, IDictionary<String^, Object^>^ paramaters);
             virtual IRegistration^ AddDevToolsMessageObserver(IDevToolsMessageObserver^ observer);
+            virtual int GetNextDevToolsMessageId();
 
             virtual void AddWordToDictionary(String^ word);
             virtual void ReplaceMisspelling(String^ word);

CefSharp/DevTools/DevToolsClient.cs

@@ -19,11 +19,6 @@ namespace CefSharp.DevTools
     /// </summary>
     public partial class DevToolsClient : IDevToolsMessageObserver, IDevToolsClient
     {
-        //TODO: Message Id is now global, limits the number of messages to int.MaxValue
-        //Needs to be unique and incrementing per browser with the option to have multiple
-        //DevToolsClient instances per browser.
-        private static int lastMessageId = 0;
-
         private readonly ConcurrentDictionary<int, DevToolsMethodResponseContext> queuedCommandResults = new ConcurrentDictionary<int, DevToolsMethodResponseContext>();
         private readonly ConcurrentDictionary<string, EventHandler<Stream>> eventHandlers = new ConcurrentDictionary<string, EventHandler<Stream>>();
         private IBrowser browser;
@@ -138,8 +133,6 @@ public Task<T> ExecuteDevToolsMethodAsync<T>(string method, IDictionary<string,
                 throw new ObjectDisposedException(nameof(IBrowser));
             }
 
-            var messageId = Interlocked.Increment(ref lastMessageId);
-
             var taskCompletionSource = new TaskCompletionSource<T>();
 
             var methodResultContext = new DevToolsMethodResponseContext(
@@ -149,13 +142,15 @@ public Task<T> ExecuteDevToolsMethodAsync<T>(string method, IDictionary<string,
                 syncContext: CaptureSyncContext ? SynchronizationContext.Current : SyncContext
             );
 
+            var browserHost = browser.GetHost();
+
+            var messageId = browserHost.GetNextDevToolsMessageId();
+
             if (!queuedCommandResults.TryAdd(messageId, methodResultContext))
             {
                 throw new DevToolsClientException(string.Format("Unable to add MessageId {0} to queuedCommandResults ConcurrentDictionary.", messageId));
             }
 
-            var browserHost = browser.GetHost();
-
             //Currently on CEF UI Thread we can directly execute
             if (CefThread.CurrentlyOnUiThread)
             {

CefSharp/IBrowserHost.cs

@@ -127,6 +127,13 @@ public interface IBrowserHost : IDisposable
         /// successfully submitted for validation, otherwise 0</returns>
         int ExecuteDevToolsMethod(int messageId, string method, IDictionary<string, object> parameters = null);
 
+        /// <summary>
+        /// Returns the next unique message id which can be used in <see cref="ExecuteDevToolsMethod(int, string, string)"/> or
+        /// <see cref="ExecuteDevToolsMethod(int, string, IDictionary{string, object})"/>.
+        /// </summary>
+        /// <returns>The next unique message id.</returns>
+        int GetNextDevToolsMessageId();
+
         /// <summary>
         /// Add an observer for DevTools protocol messages (method results and events).
         /// The observer will remain registered until the returned Registration object