Add a configuration flag to disable cache files

The cache files cache.dat and mappings.bin can have
concurrency issues in case multiple instances try to access
them concurrently (see Azure Web Sites)

src/Orchard.Web/Config/HostComponents.config

@@ -74,12 +74,27 @@
 			</Properties>
 		</Component>
 
-		<Component Type="Orchard.Caching.DefaultParallelCacheContext">
-			<Properties>
-				<!-- Set Value="true" to disable parallel cache resolution -->
-				<Property Name="Disabled" Value="false"/>
-			</Properties>
-		</Component>
+    <Component Type="Orchard.Caching.DefaultParallelCacheContext">
+      <Properties>
+        <!-- Set Value="true" to disable parallel cache resolution -->
+        <Property Name="Disabled" Value="false"/>
+      </Properties>
+    </Component>
+    
+    <Component Type="Orchard.Data.SessionConfigurationCache">
+      <Properties>
+        <!-- Set Value="true" to disable session configuration cache (mappings.bin). Recommended when using multiple instances. -->
+        <Property Name="Disabled" Value="false"/>
+      </Properties>
+    </Component>
+    
+    <Component Type="Orchard.Environment.Descriptor.ShellDescriptorCache">
+      <Properties>
+        <!-- Set Value="true" to disable shell descriptors cache (cache.dat). Recommended when using multiple instances. -->
+        <Property Name="Disabled" Value="false"/>
+      </Properties>
+    </Component>
 
-	</Components>
+
+  </Components>
 </HostComponents>

src/Orchard/Data/ISessionConfigurationCache.cs

@@ -2,7 +2,7 @@ using System;
 using NHibernate.Cfg;
 
 namespace Orchard.Data {
-    public interface ISessionConfigurationCache : ISingletonDependency {
+    public interface ISessionConfigurationCache {
         Configuration GetConfiguration(Func<Configuration> builder);
     }
 }

src/Orchard/Data/SessionConfigurationCache.cs

@@ -33,8 +33,13 @@ namespace Orchard.Data {
         }
 
         public ILogger Logger { get; set; }
+        public bool Disabled { get; set; }
 
         public Configuration GetConfiguration(Func<Configuration> builder) {
+            if (Disabled) {
+                return builder();
+            }
+
             var hash = ComputeHash().Value;
 
             // if the current configuration is unchanged, return it

src/Orchard/Environment/Descriptor/ShellDescriptorCache.cs

@@ -42,11 +42,13 @@ namespace Orchard.Environment.Descriptor {
 
         public ILogger Logger { get; set; }
         public Localizer T { get; set; }
+        public bool Disabled { get; set; }
 
-        #region Implementation of IShellDescriptorCache
-
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Reliability", "CA2000:Dispose objects before losing scope", Justification = "StringReader closed by XmlReader.")]
         public ShellDescriptor Fetch(string name) {
+            if (Disabled) {
+                return null;
+            }
+
             lock (_synLock) {
                 VerifyCacheFile();
                 var text = _appDataFolder.ReadFile(DescriptorCacheFileName);
@@ -67,8 +69,11 @@ namespace Orchard.Environment.Descriptor {
 
         }
 
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Reliability", "CA2000:Dispose objects before losing scope", Justification = "writer closed by xmlWriter.")]
         public void Store(string name, ShellDescriptor descriptor) {
+            if (Disabled) {
+                return;
+            }
+
             lock (_synLock) {
                 VerifyCacheFile();
                 var text = _appDataFolder.ReadFile(DescriptorCacheFileName);
@@ -97,8 +102,6 @@ namespace Orchard.Environment.Descriptor {
             }
         }
 
-        #endregion
-
         private static string GetCacheTextForShellDescriptor(ShellDescriptor descriptor) {
             var sb = new StringBuilder();
             sb.Append(descriptor.SerialNumber + "|");
@@ -125,19 +128,19 @@ namespace Orchard.Environment.Descriptor {
             return shellDescriptor;
         }
 
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Reliability", "CA2000:Dispose objects before losing scope")]
+        /// <summary>
+        /// Creates an empty cache file if it doesn't exist already
+        /// </summary>
         private void VerifyCacheFile() {
             if (!_appDataFolder.FileExists(DescriptorCacheFileName)) {
                 var writer = new StringWriter();
-                using (XmlWriter xmlWriter = XmlWriter.Create(writer)) {
-                    if (xmlWriter != null) {
-                        xmlWriter.WriteStartDocument();
-                        xmlWriter.WriteStartElement("Tenants");
-                        xmlWriter.WriteEndElement();
-                        xmlWriter.WriteEndDocument();
-                    }
+                using (var xmlWriter = XmlWriter.Create(writer)) {
+                    xmlWriter.WriteStartDocument();
+                    xmlWriter.WriteStartElement("Tenants");
+                    xmlWriter.WriteEndElement();
+                    xmlWriter.WriteEndDocument();
                 }
-                _appDataFolder.CreateFile(DescriptorCacheFileName, writer.ToString());
+                _appDataFolder.CreateFile(DescriptorCacheFileName, writer.ToString());                
             }
         }
     }

src/Orchard/Environment/HostComponentsConfigModule.cs

@@ -94,10 +94,10 @@ namespace Orchard.Environment {
                     PropertyInfo = p,
                     IndexParameters = p.GetIndexParameters(),
                     Accessors = p.GetAccessors(false),
-                    PropertyEntry = properties.Where(t => t.Name == p.Name).FirstOrDefault()
+                    PropertyEntry = properties.FirstOrDefault(t => t.Name == p.Name)
                 })
                 .Where(x => x.PropertyEntry != null) // Must be present in "properties"
-                .Where(x => x.IndexParameters.Count() == 0) // must not be an indexer
+                .Where(x => !x.IndexParameters.Any()) // must not be an indexer
                 .Where(x => x.Accessors.Length != 1 || x.Accessors[0].ReturnType == typeof(void)); //must have get/set, or only set
 
             // Return an array of actions that assign the property value

src/Orchard/Environment/OrchardStarter.cs

@@ -9,6 +9,7 @@ using System.Web.Mvc;
 using Autofac;
 using Autofac.Configuration;
 using Orchard.Caching;
+using Orchard.Data;
 using Orchard.Environment.AutofacUtil;
 using Orchard.Environment.Configuration;
 using Orchard.Environment.Extensions;
@@ -119,10 +120,10 @@ namespace Orchard.Environment {
 
             builder.RegisterType<RunningShellTable>().As<IRunningShellTable>().SingleInstance();
             builder.RegisterType<DefaultOrchardShell>().As<IOrchardShell>().InstancePerMatchingLifetimeScope("shell");
+            builder.RegisterType<SessionConfigurationCache>().As<ISessionConfigurationCache>().InstancePerMatchingLifetimeScope("shell");
 
             registrations(builder);
 
-
             var autofacSection = ConfigurationManager.GetSection(ConfigurationSettingsReaderConstants.DefaultSectionName);
             if (autofacSection != null)
                 builder.RegisterModule(new ConfigurationSettingsReader());
@@ -135,7 +136,6 @@ namespace Orchard.Environment {
             if (File.Exists(optionalComponentsConfig))
                 builder.RegisterModule(new HostComponentsConfigModule(optionalComponentsConfig));
 
-
             var container = builder.Build();
 
             //

src/Orchard/FileSystems/LockFile/DefaultLockFileManager.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Globalization;
 using System.Threading;
 using Orchard.FileSystems.AppData;
 using Orchard.Services;
@@ -26,7 +27,7 @@ namespace Orchard.FileSystems.LockFile {
                     return false;
                 }
 
-                lockFile = new LockFile(_appDataFolder, path, _clock.UtcNow.ToString(), _rwLock);
+                lockFile = new LockFile(_appDataFolder, path, _clock.UtcNow.ToString(CultureInfo.InvariantCulture), _rwLock);
                 return true;
             }
             catch {