[XrdCl] Provide compatibility between root://localfile and file://.

The 'root://localfile//path/filename.meta4' semantic is now deprecated,
and 'file://localhost/path/filename.meta4' instead!
This commit provides compatibility with the old method of accessing
local metalink files.

docs/man/xrdcp.1

@@ -438,7 +438,8 @@ Enable/Disable Metalink processing (enabled by default)
 
 XRD_LOCALMETALINKFILE
 .RS 5
-Enable/Disable local Metalink file processing (by convention the following URL schema has to be used: root://localfile//path/filename.meta4) 
+Enable/Disable local Metalink file processing (by convention the following URL schema has to be used: root://localfile//path/filename.meta4)
+The 'localfile' semantic is now deprecated, use file://localhost/path/filename.meta4 instead!
 .RE
 
 XRD_GLFNREDIRECTOR

src/XrdCl/XrdClConstants.hh

@@ -65,7 +65,7 @@ namespace XrdCl
   const int DefaultMultiProtocol        = 0;
   const int DefaultParallelEvtLoop      = 1;
   const int DefaultMetalinkProcessing   = 1;
-  const int DefaultLocalMetalinkFile    = 1;
+  const int DefaultLocalMetalinkFile    = 0;
   const int DefaultXCpBlockSize         = 134217728; // DefaultCPChunkSize * DefaultCPParallelChunks * 2
   const int DefaultNoDelay              = 1;
   const int DefaultPreferIPv4           = 0;

src/XrdCl/XrdClRedirectorRegistry.cc

@@ -8,6 +8,9 @@
 #include "XrdClRedirectorRegistry.hh"
 #include "XrdCl/XrdClMetalinkRedirector.hh"
 #include "XrdCl/XrdClPostMasterInterfaces.hh"
+#include "XrdCl/XrdClDefaultEnv.hh"
+#include "XrdCl/XrdClConstants.hh"
+#include "XrdCl/XrdClLog.hh"
 
 #include <arpa/inet.h>
 
@@ -36,8 +39,10 @@ RedirectorRegistry::~RedirectorRegistry()
     delete itr->second.first;
 }
 
-XRootDStatus RedirectorRegistry::RegisterImpl( const URL &url, ResponseHandler *handler )
+XRootDStatus RedirectorRegistry::RegisterImpl( const URL &u, ResponseHandler *handler )
 {
+  URL url = ConvertLocalfile( u );
+
   // we can only create a virtual redirector if
   // a path to a metadata file has been provided
   if( url.GetPath().empty() ) return XRootDStatus( stError, errNotSupported );
@@ -73,6 +78,28 @@ XRootDStatus RedirectorRegistry::RegisterImpl( const URL &url, ResponseHandler *
     return XRootDStatus( stError, errNotSupported );
 }
 
+URL RedirectorRegistry::ConvertLocalfile( const URL &url )
+{
+  int localml = DefaultLocalMetalinkFile;
+  DefaultEnv::GetEnv()->GetInt( "LocalMetalinkFile", localml );
+
+  if( localml && url.GetProtocol() == "root" && url.GetHostName() == "localfile" )
+  {
+    Log *log = DefaultEnv::GetLog();
+    log->Warning( PostMasterMsg,
+                  "Please note that the 'root://localfile//path/filename.meta4' "
+                  "semantic is now deprecated, use 'file://localhost/path/filename.meta4'"
+                  "instead!" );
+
+    URL copy( url );
+    copy.SetHostName( "localhost" );
+    copy.SetProtocol( "file" );
+    return copy;
+  }
+
+  return url;
+}
+
 XRootDStatus RedirectorRegistry::Register( const URL &url )
 {
   return RegisterImpl( url, 0 );
@@ -86,8 +113,10 @@ XRootDStatus RedirectorRegistry::RegisterAndWait( const URL &url )
   return MessageUtils::WaitForStatus( &handler );
 }
 
-VirtualRedirector* RedirectorRegistry::Get( const URL &url ) const
+VirtualRedirector* RedirectorRegistry::Get( const URL &u ) const
 {
+  URL url = ConvertLocalfile( u );
+
   XrdSysMutexHelper scopedLock( pMutex );
   // get the key and return the value if it is in the registry
   // offset 24 is where the path has been stored
@@ -102,8 +131,10 @@ VirtualRedirector* RedirectorRegistry::Get( const URL &url ) const
 //----------------------------------------------------------------------------
 // Release the virtual redirector associated with the given URL
 //----------------------------------------------------------------------------
-void RedirectorRegistry::Release( const URL &url )
+void RedirectorRegistry::Release( const URL &u )
 {
+  URL url = ConvertLocalfile( u );
+
   XrdSysMutexHelper scopedLock( pMutex );
   // get the key and return the value if it is in the registry
   // offset 24 is where the path has been stored

src/XrdCl/XrdClRedirectorRegistry.hh

@@ -147,6 +147,14 @@ class RedirectorRegistry
     //----------------------------------------------------------------------------
     XRootDStatus RegisterImpl( const URL &url, ResponseHandler *handler );
 
+    //----------------------------------------------------------------------------
+    //! Convert the old convention for accessing local metalink files:
+    //!   root://localfile//path/metalink.meta4
+    //! into:
+    //!   file://localhost/path/metalink.meta4
+    //----------------------------------------------------------------------------
+    static URL ConvertLocalfile( const URL &url );
+
     //----------------------------------------------------------------------------
     // Constructor (private!).
     //----------------------------------------------------------------------------