diff --git a/mozilla/modules/libreg/xpcom/nsRegistry.cpp b/mozilla/modules/libreg/xpcom/nsRegistry.cpp
index e45c2a37ed3..9cde3fd21a7 100644
--- a/mozilla/modules/libreg/xpcom/nsRegistry.cpp
+++ b/mozilla/modules/libreg/xpcom/nsRegistry.cpp
@@ -55,6 +55,7 @@ struct nsRegistry : public nsIRegistry {
     NS_IMETHOD OpenWellKnownRegistry( uint32 regid );
     NS_IMETHOD OpenDefault();
     NS_IMETHOD Close();
+    NS_IMETHOD IsOpen( PRBool *result );
 
     NS_IMETHOD GetString( Key baseKey, const char *path, char **result );
     NS_IMETHOD SetString( Key baseKey, const char *path, const char *value );
@@ -492,6 +493,15 @@ NS_IMETHODIMP nsRegistry::Close() {
     return regerr2nsresult( err );
 }
 
+/*----------------------------- nsRegistry::IsOpen -----------------------------
+| Tests the mReg handle and returns whether the registry is open or not.       |
+------------------------------------------------------------------------------*/
+NS_IMETHODIMP nsRegistry::IsOpen( PRBool *result ) {
+    *result = ( mReg != 0 );
+    return NS_OK;
+}
+
+
 /*--------------------------- nsRegistry::GetString ----------------------------
 | First, look for the entry using GetValueInfo.  If found, and it's a string,  |
 | allocate space for it and fetch the value.                                   |
diff --git a/mozilla/xpcom/components/nsIRegistry.h b/mozilla/xpcom/components/nsIRegistry.h
index 44489588f10..4fadece1bc9 100644
--- a/mozilla/xpcom/components/nsIRegistry.h
+++ b/mozilla/xpcom/components/nsIRegistry.h
@@ -168,6 +168,7 @@ struct nsIRegistry : public nsISupports {
     NS_IMETHOD OpenWellKnownRegistry( uint32 regid ) = 0;
     NS_IMETHOD OpenDefault() = 0;
     NS_IMETHOD Close() = 0;
+    NS_IMETHOD IsOpen( PRBool *result ) = 0;
 
     /*----------------------- Reading/Writing Values ---------------------------
     | These functions read/write the registry values at a given node.          |
diff --git a/mozilla/xpcom/components/nsRegistry.cpp b/mozilla/xpcom/components/nsRegistry.cpp
index e45c2a37ed3..9cde3fd21a7 100644
--- a/mozilla/xpcom/components/nsRegistry.cpp
+++ b/mozilla/xpcom/components/nsRegistry.cpp
@@ -55,6 +55,7 @@ struct nsRegistry : public nsIRegistry {
     NS_IMETHOD OpenWellKnownRegistry( uint32 regid );
     NS_IMETHOD OpenDefault();
     NS_IMETHOD Close();
+    NS_IMETHOD IsOpen( PRBool *result );
 
     NS_IMETHOD GetString( Key baseKey, const char *path, char **result );
     NS_IMETHOD SetString( Key baseKey, const char *path, const char *value );
@@ -492,6 +493,15 @@ NS_IMETHODIMP nsRegistry::Close() {
     return regerr2nsresult( err );
 }
 
+/*----------------------------- nsRegistry::IsOpen -----------------------------
+| Tests the mReg handle and returns whether the registry is open or not.       |
+------------------------------------------------------------------------------*/
+NS_IMETHODIMP nsRegistry::IsOpen( PRBool *result ) {
+    *result = ( mReg != 0 );
+    return NS_OK;
+}
+
+
 /*--------------------------- nsRegistry::GetString ----------------------------
 | First, look for the entry using GetValueInfo.  If found, and it's a string,  |
 | allocate space for it and fetch the value.                                   |