expose whether the registry is already open or not, which enables the profile

manager to avoid opening and closing the registry ~20 times at startup.

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.                                   |

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.          |

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.                                   |