Specialize IVirtualPathMonitor for command line host

More deterministic behavior and no file locking at
the expense of performance.

--HG--
branch : dev

src/Orchard/Commands/CommandHostAgent.cs

@@ -8,6 +8,7 @@ using Autofac;
 using Orchard.Environment;
 using Orchard.Environment.Configuration;
 using Orchard.Environment.State;
+using Orchard.FileSystems.VirtualPath;
 using Orchard.Localization;
 using Orchard.Logging;
 using Orchard.Tasks;
@@ -153,6 +154,7 @@ namespace Orchard.Commands {
             MvcSingletons(builder);
             builder.RegisterType<CommandHostEnvironment>().As<IHostEnvironment>();
             builder.RegisterType<CommandBackgroundService>().As<IBackgroundService>();
+            builder.RegisterType<CommandHostVirtualPathMonitor>().As<IVirtualPathMonitor>();
         }
 
         protected void MvcSingletons(ContainerBuilder builder) {

src/Orchard/Commands/CommandHostEnvironment.cs

@@ -1,25 +1,10 @@
 using System;
 using System.Linq;
-using System.Runtime.Serialization;
 using System.Web.Hosting;
 using Orchard.Environment;
 using Orchard.Localization;
 
 namespace Orchard.Commands {
-    public class OrchardCommandHostRetryException : OrchardCoreException {
-        public OrchardCommandHostRetryException(LocalizedString message)
-            : base(message) {
-        }
-
-        public OrchardCommandHostRetryException(LocalizedString message, Exception innerException)
-            : base(message, innerException) {
-        }
-
-        protected OrchardCommandHostRetryException(SerializationInfo info, StreamingContext context)
-            : base(info, context) {
-        }
-    }
-
     public class CommandHostEnvironment : IHostEnvironment {
         public CommandHostEnvironment() {
             T = NullLocalizer.Instance;

src/Orchard/Commands/CommandHostVirtualPathMonitor.cs

@@ -0,0 +1,93 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using Orchard.Caching;
+using Orchard.FileSystems.VirtualPath;
+
+namespace Orchard.Commands {
+    public class CommandHostVirtualPathMonitor : IVirtualPathMonitor {
+        private readonly IVirtualPathProvider _virtualPathProvider;
+
+        public CommandHostVirtualPathMonitor(IVirtualPathProvider virtualPathProvider) {
+            _virtualPathProvider = virtualPathProvider;
+        }
+
+        public IVolatileToken WhenPathChanges(string virtualPath) {
+            var filename = _virtualPathProvider.MapPath(virtualPath);
+            if (File.Exists(filename)) {
+                return new FileToken(filename);
+            }
+            if (Directory.Exists(filename)) {
+                return new DirectoryToken(filename);
+            }
+            return new EmptyVolativeToken(filename);
+        }
+
+        public class EmptyVolativeToken : IVolatileToken {
+            private readonly string _filename;
+
+            public EmptyVolativeToken(string filename) {
+                _filename = filename;
+            }
+
+            public bool IsCurrent {
+                get {
+                    if (Directory.Exists(_filename)) {
+                        return false;
+                    }
+                    if (File.Exists(_filename)) {
+                        return false;
+                    }
+                    return true;
+                }
+            }
+        }
+
+        public class FileToken : IVolatileToken {
+            private readonly string _filename;
+            private readonly DateTime _lastWriteTimeUtc;
+
+            public FileToken(string filename) {
+                _filename = filename;
+                _lastWriteTimeUtc = File.GetLastWriteTimeUtc(filename);
+            }
+
+            public bool IsCurrent {
+                get {
+                    try {
+                        if (_lastWriteTimeUtc != File.GetLastWriteTimeUtc(_filename))
+                            return false;
+                    }
+                    catch {
+                        return false;
+                    }
+                    return true;
+                }
+            }
+        }
+
+        public class DirectoryToken : IVolatileToken {
+            private readonly string _filename;
+            private readonly DateTime _lastWriteTimeUtc;
+
+            public DirectoryToken(string filename) {
+                _filename = filename;
+                _lastWriteTimeUtc = Directory.GetLastWriteTimeUtc(filename);
+            }
+
+            public bool IsCurrent {
+                get {
+                    try {
+                        if (_lastWriteTimeUtc != Directory.GetLastWriteTimeUtc(_filename))
+                            return false;
+                    }
+                    catch {
+                        return false;
+                    }
+                    return true;
+                }
+            }
+        }
+    }
+}

src/Orchard/Commands/OrchardCommandHostRetryException.cs

@@ -0,0 +1,19 @@
+using System;
+using System.Runtime.Serialization;
+using Orchard.Localization;
+
+namespace Orchard.Commands {
+    public class OrchardCommandHostRetryException : OrchardCoreException {
+        public OrchardCommandHostRetryException(LocalizedString message)
+            : base(message) {
+        }
+
+        public OrchardCommandHostRetryException(LocalizedString message, Exception innerException)
+            : base(message, innerException) {
+        }
+
+        protected OrchardCommandHostRetryException(SerializationInfo info, StreamingContext context)
+            : base(info, context) {
+        }
+    }
+}

src/Orchard/Orchard.Framework.csproj

@@ -135,6 +135,8 @@
     <Compile Include="Collections\PageOfItems.cs" />
     <Compile Include="Commands\CommandBackgroundService.cs" />
     <Compile Include="Commands\CommandHostEnvironment.cs" />
+    <Compile Include="Commands\CommandHostVirtualPathMonitor.cs" />
+    <Compile Include="Commands\OrchardCommandHostRetryException.cs" />
     <Compile Include="ContentManagement\Aspects\ICommonPart.cs">
       <SubType>Code</SubType>
     </Compile>