diff --git a/mozilla/mailnews/absync/src/nsAbSync.cpp b/mozilla/mailnews/absync/src/nsAbSync.cpp
index fe9ce28fa7d..6c9ffd3fe5c 100644
--- a/mozilla/mailnews/absync/src/nsAbSync.cpp
+++ b/mozilla/mailnews/absync/src/nsAbSync.cpp
@@ -2822,7 +2822,7 @@ nsAbSync::AddValueToNewCard(nsIAbCard *aCard, nsString *aTagName, nsString *aTag
   tValue = aTagValue->ToNewCString();
   if (tValue)
   {
-    rv = nsMsgI18NConvertToUnicode(nsCString("UTF-8"), nsCString(tValue), outValue);
+    rv = nsMsgI18NConvertToUnicode(nsCAutoString("UTF-8"), nsCAutoString(tValue), outValue);
     if (NS_SUCCEEDED(rv))
       aTagValue->Assign(outValue);
     PR_FREEIF(tValue);
diff --git a/mozilla/mailnews/import/src/nsImportFieldMap.cpp b/mozilla/mailnews/import/src/nsImportFieldMap.cpp
index 22902a15c2c..6186872d6ad 100644
--- a/mozilla/mailnews/import/src/nsImportFieldMap.cpp
+++ b/mozilla/mailnews/import/src/nsImportFieldMap.cpp
@@ -241,7 +241,7 @@ NS_IMETHODIMP nsImportFieldMap::SetFieldValue(nsIAddrDatabase *database, nsIMdbR
 	// UGGG!!!!! lot's of typing here!
 	nsresult rv;
 	
-	nsString str = value;
+	nsString str(value);
 	char *pVal = str.ToNewUTF8String();
 
 	switch( fieldNum) {
diff --git a/mozilla/mailnews/import/src/nsImportService.cpp b/mozilla/mailnews/import/src/nsImportService.cpp
index be6d7675d0c..a848aac28a4 100644
--- a/mozilla/mailnews/import/src/nsImportService.cpp
+++ b/mozilla/mailnews/import/src/nsImportService.cpp
@@ -656,7 +656,7 @@ PRBool ImportModuleDesc::SupportsThings( const char *pThings)
 	if (!(*pThings))
 		return( PR_TRUE);
 
-	nsCString	thing = pThings;
+	nsCString	thing(pThings);
 	nsCString	item;
 	PRInt32		idx;
 	
diff --git a/mozilla/mailnews/news/src/nsNntpIncomingServer.cpp b/mozilla/mailnews/news/src/nsNntpIncomingServer.cpp
index c4c73312a56..24e567c4073 100644
--- a/mozilla/mailnews/news/src/nsNntpIncomingServer.cpp
+++ b/mozilla/mailnews/news/src/nsNntpIncomingServer.cpp
@@ -1235,6 +1235,6 @@ NS_IMETHODIMP
 nsNntpIncomingServer::RemoveNewsgroup(const char *name)
 {
 	// handle duplicates?
-	mSubscribedNewsgroups.RemoveCString(nsCString(name));
+	mSubscribedNewsgroups.RemoveCString(nsCAutoString(name));
 	return NS_OK;
 }
diff --git a/mozilla/netwerk/mime/src/nsMIMEInfoImpl.cpp b/mozilla/netwerk/mime/src/nsMIMEInfoImpl.cpp
index 8804d804020..3e5c7a7bb41 100644
--- a/mozilla/netwerk/mime/src/nsMIMEInfoImpl.cpp
+++ b/mozilla/netwerk/mime/src/nsMIMEInfoImpl.cpp
@@ -96,7 +96,7 @@ nsMIMEInfoImpl::FirstExtension(char **_retval) {
 
 NS_IMETHODIMP nsMIMEInfoImpl::AppendExtension(const char *aExtension)
 {
-	mExtensions.AppendCString( nsCString(aExtension) );
+	mExtensions.AppendCString( nsCAutoString(aExtension) );
 	return NS_OK;
 }
 
diff --git a/mozilla/netwerk/mime/src/nsXMLMIMEDataSource.cpp b/mozilla/netwerk/mime/src/nsXMLMIMEDataSource.cpp
index cc588aebc5e..ad25216c266 100644
--- a/mozilla/netwerk/mime/src/nsXMLMIMEDataSource.cpp
+++ b/mozilla/netwerk/mime/src/nsXMLMIMEDataSource.cpp
@@ -116,7 +116,7 @@ nsXMLMIMEDataSource::AddMapping(const char* mimeType,
     nsMIMEInfoImpl* anInfo = new nsMIMEInfoImpl(mimeType);
     if (!anInfo) return NS_ERROR_OUT_OF_MEMORY;
 
-    anInfo->mExtensions.AppendCString(nsCString(extension));
+    anInfo->mExtensions.AppendCString(nsCAutoString(extension));
     anInfo->mDescription.AssignWithConversion(description);
     anInfo->mURI = dataURI;
 
@@ -233,7 +233,7 @@ nsXMLMIMEDataSource::AppendExtension(const char* mimeType, const char* extension
     nsMIMEInfoImpl* info = (nsMIMEInfoImpl*)mInfoObjects->Get(&key);
     if (!info) return NS_ERROR_FAILURE;
 
-    info->mExtensions.AppendCString(nsCString(extension));
+    info->mExtensions.AppendCString(nsCAutoString(extension));
 
     // Add another file extension mapping.
     key = extension;
@@ -255,7 +255,7 @@ nsXMLMIMEDataSource::RemoveExtension(const char* aExtension) {
     
     // Next remove the root MIME mapping from the array and hash
     // IFF this was the only file extension mapping left.
-    PRBool removed = info->mExtensions.RemoveCString(nsCString(aExtension));
+    PRBool removed = info->mExtensions.RemoveCString(nsCAutoString(aExtension));
     NS_ASSERTION(removed, "mapping problem");
 
     if (info->GetExtCount() == 0) {
diff --git a/mozilla/netwerk/protocol/about/src/nsAboutBlank.cpp b/mozilla/netwerk/protocol/about/src/nsAboutBlank.cpp
index 6196258979b..b59574aebd6 100644
--- a/mozilla/netwerk/protocol/about/src/nsAboutBlank.cpp
+++ b/mozilla/netwerk/protocol/about/src/nsAboutBlank.cpp
@@ -38,7 +38,7 @@ nsAboutBlank::NewChannel(nsIURI *aURI, nsIChannel **result)
     nsresult rv;
     nsIChannel* channel;
     nsISupports* s;
-    rv = NS_NewCStringInputStream(&s, nsCString(kBlankPage));
+    rv = NS_NewCStringInputStream(&s, nsCAutoString(kBlankPage));
     if (NS_FAILED(rv)) return rv;
     nsIInputStream* in;
 
diff --git a/mozilla/netwerk/protocol/about/src/nsAboutBloat.cpp b/mozilla/netwerk/protocol/about/src/nsAboutBloat.cpp
index 2437fe5d383..0366192b191 100644
--- a/mozilla/netwerk/protocol/about/src/nsAboutBloat.cpp
+++ b/mozilla/netwerk/protocol/about/src/nsAboutBloat.cpp
@@ -74,7 +74,7 @@ nsAboutBloat::NewChannel(nsIURI *aURI, nsIChannel **result)
 
         nsCOMPtr<nsISupports> s;
         const char* msg = "Bloat statistics cleared.";
-        rv = NS_NewCStringInputStream(getter_AddRefs(s), nsCString(msg));
+        rv = NS_NewCStringInputStream(getter_AddRefs(s), nsCAutoString(msg));
         if (NS_FAILED(rv)) return rv;
 
         size = nsCRT::strlen(msg);
@@ -88,7 +88,7 @@ nsAboutBloat::NewChannel(nsIURI *aURI, nsIChannel **result)
     	
         nsCOMPtr<nsISupports> s;
         const char* msg = "Memory leaks dumped.";
-        rv = NS_NewCStringInputStream(getter_AddRefs(s), nsCString(msg));
+        rv = NS_NewCStringInputStream(getter_AddRefs(s), nsCAutoString(msg));
         if (NS_FAILED(rv)) return rv;
 
         size = nsCRT::strlen(msg);
diff --git a/mozilla/netwerk/protocol/http/src/nsHTTPHandler.cpp b/mozilla/netwerk/protocol/http/src/nsHTTPHandler.cpp
index b371342ed9d..12dd9cc72c6 100644
--- a/mozilla/netwerk/protocol/http/src/nsHTTPHandler.cpp
+++ b/mozilla/netwerk/protocol/http/src/nsHTTPHandler.cpp
@@ -314,7 +314,7 @@ nsHTTPHandler::NewPostDataStream(PRBool isFile,
     }
     else {
         nsCOMPtr<nsISupports> in;
-        rv = NS_NewCStringInputStream(getter_AddRefs(in), nsCString(data));
+        rv = NS_NewCStringInputStream(getter_AddRefs(in), nsCAutoString(data));
         if (NS_FAILED(rv)) return rv;
 
         rv = in->QueryInterface(NS_GET_IID(nsIInputStream),(void**)result);
diff --git a/mozilla/string/obsolete/nsString.h b/mozilla/string/obsolete/nsString.h
index 62f1f10c94d..1385e13411e 100644
--- a/mozilla/string/obsolete/nsString.h
+++ b/mozilla/string/obsolete/nsString.h
@@ -110,9 +110,9 @@ public:
   nsCString(const nsCString& aString);   
 
 #ifdef NEW_STRING_APIS
-  nsCString( const nsAReadableCString& );
+  explicit nsCString( const nsAReadableCString& );
 
-  nsCString(const char*);
+  explicit nsCString(const char*);
   nsCString(const char*, PRInt32);
 #else
   /**
@@ -833,10 +833,11 @@ public:
     virtual ~nsCAutoString();
 
     nsCAutoString();
-    nsCAutoString(const nsCString& );
-    nsCAutoString(const char* aString);
+    // why does this class have no copy constructor?  nsCAutoString( const nsCAutoString& );
+    explicit nsCAutoString(const nsCString& );
+    explicit nsCAutoString(const char* aString);
     nsCAutoString(const char* aString,PRInt32 aLength);
-    nsCAutoString(const CBufDescriptor& aBuffer);
+    explicit nsCAutoString(const CBufDescriptor& aBuffer);
 
 #ifndef NEW_STRING_APIS
 //  nsCAutoString(const PRUnichar* aString,PRInt32 aLength=-1);
@@ -895,6 +896,7 @@ class NS_COM NS_ConvertUCS2toUTF8
     */
   {
     public:
+      explicit
       NS_ConvertUCS2toUTF8( const PRUnichar* aString )
         {
           Init( aString, ~PRUint32(0) /* MAXINT */);
@@ -905,6 +907,7 @@ class NS_COM NS_ConvertUCS2toUTF8
           Init( aString, aLength );
         }
 
+      explicit
       NS_ConvertUCS2toUTF8( PRUnichar aChar )
         {
           Init( &aChar, 1 );
@@ -939,7 +942,7 @@ class NS_COM NS_ConvertUCS2toUTF8
  ***************************************************************/
 class NS_COM nsSubsumeCStr : public nsCString {
 public:
-  nsSubsumeCStr(nsStr& aString);
+  explicit nsSubsumeCStr(nsStr& aString);
   nsSubsumeCStr(PRUnichar* aString,PRBool assumeOwnership,PRInt32 aLength=-1);
   nsSubsumeCStr(char* aString,PRBool assumeOwnership,PRInt32 aLength=-1);
 
diff --git a/mozilla/string/obsolete/nsString2.h b/mozilla/string/obsolete/nsString2.h
index cec472b57ec..e4c5750a165 100644
--- a/mozilla/string/obsolete/nsString2.h
+++ b/mozilla/string/obsolete/nsString2.h
@@ -104,9 +104,9 @@ public:
   nsString(const nsString& aString);   
 
 #ifdef NEW_STRING_APIS
-  nsString(const nsAReadableString&);
+  explicit nsString(const nsAReadableString&);
 
-  nsString(const PRUnichar*);
+  explicit nsString(const PRUnichar*);
   nsString(const PRUnichar*, PRInt32);
 #else
   /**
@@ -924,11 +924,11 @@ public:
     virtual ~nsAutoString();
     nsAutoString();
     nsAutoString(const nsAutoString& aString);
-    nsAutoString(const nsString& aString);
-    nsAutoString(const PRUnichar* aString);
+    explicit nsAutoString(const nsString& aString);
+    explicit nsAutoString(const PRUnichar* aString);
     nsAutoString(const PRUnichar* aString,PRInt32 aLength);
-    nsAutoString(PRUnichar aChar);
-    nsAutoString(const CBufDescriptor& aBuffer);    
+    explicit nsAutoString(PRUnichar aChar);
+    explicit nsAutoString(const CBufDescriptor& aBuffer);    
 
 #ifndef NEW_STRING_APIS
 //  nsAutoString(const char* aCString,PRInt32 aLength=-1);
@@ -979,15 +979,15 @@ class NS_COM NS_ConvertASCIItoUCS2
     */
   {
     public:
-      NS_ConvertASCIItoUCS2( const char* );
+      explicit NS_ConvertASCIItoUCS2( const char* );
       NS_ConvertASCIItoUCS2( const char*, PRUint32 );
-      NS_ConvertASCIItoUCS2( char );
+      explicit NS_ConvertASCIItoUCS2( char );
 #if 0
 #ifdef NEW_STRING_APIS
-      NS_ConvertASCIItoUCS2( const nsAReadableCString& );
+      explicit NS_ConvertASCIItoUCS2( const nsAReadableCString& );
 #else
       class nsCString;
-      NS_ConvertASCIItoUCS2( const nsCString& );
+      explicit NS_ConvertASCIItoUCS2( const nsCString& );
 #endif
 #endif
 
@@ -997,6 +997,7 @@ class NS_COM NS_ConvertASCIItoUCS2
           return GetUnicode();
         }
 
+        // is this really a good idea?  I'm getting very paranoid about automatic conversions
       operator nsLiteralString() const
         {
           return nsLiteralString(mUStr, mLength);
@@ -1035,6 +1036,7 @@ class NS_COM NS_ConvertUTF8toUCS2
       : public nsAutoString
   {
     public:
+      explicit
       NS_ConvertUTF8toUCS2( const char* aCString )
         {
           Init( aCString, ~PRUint32(0) /* MAXINT */ );
@@ -1045,6 +1047,7 @@ class NS_COM NS_ConvertUTF8toUCS2
           Init( aCString, aLength );
         }
 
+      explicit
       NS_ConvertUTF8toUCS2( char aChar )
         {
           Init( &aChar, 1 );
@@ -1078,7 +1081,7 @@ class NS_COM NS_ConvertUTF8toUCS2
 class NS_COM nsSubsumeStr : public nsString {
 public:
   nsSubsumeStr();
-  nsSubsumeStr(nsStr& aString);
+  explicit nsSubsumeStr(nsStr& aString);
   nsSubsumeStr(PRUnichar* aString,PRBool assumeOwnership,PRInt32 aLength=-1);
   nsSubsumeStr(char* aString,PRBool assumeOwnership,PRInt32 aLength=-1);
   int Subsume(PRUnichar* aString,PRBool assumeOwnership,PRInt32 aLength=-1);
diff --git a/mozilla/uriloader/exthandler/nsMIMEInfoImpl.cpp b/mozilla/uriloader/exthandler/nsMIMEInfoImpl.cpp
index 8804d804020..3e5c7a7bb41 100644
--- a/mozilla/uriloader/exthandler/nsMIMEInfoImpl.cpp
+++ b/mozilla/uriloader/exthandler/nsMIMEInfoImpl.cpp
@@ -96,7 +96,7 @@ nsMIMEInfoImpl::FirstExtension(char **_retval) {
 
 NS_IMETHODIMP nsMIMEInfoImpl::AppendExtension(const char *aExtension)
 {
-	mExtensions.AppendCString( nsCString(aExtension) );
+	mExtensions.AppendCString( nsCAutoString(aExtension) );
 	return NS_OK;
 }
 
diff --git a/mozilla/xpcom/ds/nsString.h b/mozilla/xpcom/ds/nsString.h
index 62f1f10c94d..1385e13411e 100644
--- a/mozilla/xpcom/ds/nsString.h
+++ b/mozilla/xpcom/ds/nsString.h
@@ -110,9 +110,9 @@ public:
   nsCString(const nsCString& aString);   
 
 #ifdef NEW_STRING_APIS
-  nsCString( const nsAReadableCString& );
+  explicit nsCString( const nsAReadableCString& );
 
-  nsCString(const char*);
+  explicit nsCString(const char*);
   nsCString(const char*, PRInt32);
 #else
   /**
@@ -833,10 +833,11 @@ public:
     virtual ~nsCAutoString();
 
     nsCAutoString();
-    nsCAutoString(const nsCString& );
-    nsCAutoString(const char* aString);
+    // why does this class have no copy constructor?  nsCAutoString( const nsCAutoString& );
+    explicit nsCAutoString(const nsCString& );
+    explicit nsCAutoString(const char* aString);
     nsCAutoString(const char* aString,PRInt32 aLength);
-    nsCAutoString(const CBufDescriptor& aBuffer);
+    explicit nsCAutoString(const CBufDescriptor& aBuffer);
 
 #ifndef NEW_STRING_APIS
 //  nsCAutoString(const PRUnichar* aString,PRInt32 aLength=-1);
@@ -895,6 +896,7 @@ class NS_COM NS_ConvertUCS2toUTF8
     */
   {
     public:
+      explicit
       NS_ConvertUCS2toUTF8( const PRUnichar* aString )
         {
           Init( aString, ~PRUint32(0) /* MAXINT */);
@@ -905,6 +907,7 @@ class NS_COM NS_ConvertUCS2toUTF8
           Init( aString, aLength );
         }
 
+      explicit
       NS_ConvertUCS2toUTF8( PRUnichar aChar )
         {
           Init( &aChar, 1 );
@@ -939,7 +942,7 @@ class NS_COM NS_ConvertUCS2toUTF8
  ***************************************************************/
 class NS_COM nsSubsumeCStr : public nsCString {
 public:
-  nsSubsumeCStr(nsStr& aString);
+  explicit nsSubsumeCStr(nsStr& aString);
   nsSubsumeCStr(PRUnichar* aString,PRBool assumeOwnership,PRInt32 aLength=-1);
   nsSubsumeCStr(char* aString,PRBool assumeOwnership,PRInt32 aLength=-1);
 
diff --git a/mozilla/xpcom/ds/nsString2.h b/mozilla/xpcom/ds/nsString2.h
index cec472b57ec..e4c5750a165 100644
--- a/mozilla/xpcom/ds/nsString2.h
+++ b/mozilla/xpcom/ds/nsString2.h
@@ -104,9 +104,9 @@ public:
   nsString(const nsString& aString);   
 
 #ifdef NEW_STRING_APIS
-  nsString(const nsAReadableString&);
+  explicit nsString(const nsAReadableString&);
 
-  nsString(const PRUnichar*);
+  explicit nsString(const PRUnichar*);
   nsString(const PRUnichar*, PRInt32);
 #else
   /**
@@ -924,11 +924,11 @@ public:
     virtual ~nsAutoString();
     nsAutoString();
     nsAutoString(const nsAutoString& aString);
-    nsAutoString(const nsString& aString);
-    nsAutoString(const PRUnichar* aString);
+    explicit nsAutoString(const nsString& aString);
+    explicit nsAutoString(const PRUnichar* aString);
     nsAutoString(const PRUnichar* aString,PRInt32 aLength);
-    nsAutoString(PRUnichar aChar);
-    nsAutoString(const CBufDescriptor& aBuffer);    
+    explicit nsAutoString(PRUnichar aChar);
+    explicit nsAutoString(const CBufDescriptor& aBuffer);    
 
 #ifndef NEW_STRING_APIS
 //  nsAutoString(const char* aCString,PRInt32 aLength=-1);
@@ -979,15 +979,15 @@ class NS_COM NS_ConvertASCIItoUCS2
     */
   {
     public:
-      NS_ConvertASCIItoUCS2( const char* );
+      explicit NS_ConvertASCIItoUCS2( const char* );
       NS_ConvertASCIItoUCS2( const char*, PRUint32 );
-      NS_ConvertASCIItoUCS2( char );
+      explicit NS_ConvertASCIItoUCS2( char );
 #if 0
 #ifdef NEW_STRING_APIS
-      NS_ConvertASCIItoUCS2( const nsAReadableCString& );
+      explicit NS_ConvertASCIItoUCS2( const nsAReadableCString& );
 #else
       class nsCString;
-      NS_ConvertASCIItoUCS2( const nsCString& );
+      explicit NS_ConvertASCIItoUCS2( const nsCString& );
 #endif
 #endif
 
@@ -997,6 +997,7 @@ class NS_COM NS_ConvertASCIItoUCS2
           return GetUnicode();
         }
 
+        // is this really a good idea?  I'm getting very paranoid about automatic conversions
       operator nsLiteralString() const
         {
           return nsLiteralString(mUStr, mLength);
@@ -1035,6 +1036,7 @@ class NS_COM NS_ConvertUTF8toUCS2
       : public nsAutoString
   {
     public:
+      explicit
       NS_ConvertUTF8toUCS2( const char* aCString )
         {
           Init( aCString, ~PRUint32(0) /* MAXINT */ );
@@ -1045,6 +1047,7 @@ class NS_COM NS_ConvertUTF8toUCS2
           Init( aCString, aLength );
         }
 
+      explicit
       NS_ConvertUTF8toUCS2( char aChar )
         {
           Init( &aChar, 1 );
@@ -1078,7 +1081,7 @@ class NS_COM NS_ConvertUTF8toUCS2
 class NS_COM nsSubsumeStr : public nsString {
 public:
   nsSubsumeStr();
-  nsSubsumeStr(nsStr& aString);
+  explicit nsSubsumeStr(nsStr& aString);
   nsSubsumeStr(PRUnichar* aString,PRBool assumeOwnership,PRInt32 aLength=-1);
   nsSubsumeStr(char* aString,PRBool assumeOwnership,PRInt32 aLength=-1);
   int Subsume(PRUnichar* aString,PRBool assumeOwnership,PRInt32 aLength=-1);
diff --git a/mozilla/xpcom/string/obsolete/nsString.h b/mozilla/xpcom/string/obsolete/nsString.h
index 62f1f10c94d..1385e13411e 100644
--- a/mozilla/xpcom/string/obsolete/nsString.h
+++ b/mozilla/xpcom/string/obsolete/nsString.h
@@ -110,9 +110,9 @@ public:
   nsCString(const nsCString& aString);   
 
 #ifdef NEW_STRING_APIS
-  nsCString( const nsAReadableCString& );
+  explicit nsCString( const nsAReadableCString& );
 
-  nsCString(const char*);
+  explicit nsCString(const char*);
   nsCString(const char*, PRInt32);
 #else
   /**
@@ -833,10 +833,11 @@ public:
     virtual ~nsCAutoString();
 
     nsCAutoString();
-    nsCAutoString(const nsCString& );
-    nsCAutoString(const char* aString);
+    // why does this class have no copy constructor?  nsCAutoString( const nsCAutoString& );
+    explicit nsCAutoString(const nsCString& );
+    explicit nsCAutoString(const char* aString);
     nsCAutoString(const char* aString,PRInt32 aLength);
-    nsCAutoString(const CBufDescriptor& aBuffer);
+    explicit nsCAutoString(const CBufDescriptor& aBuffer);
 
 #ifndef NEW_STRING_APIS
 //  nsCAutoString(const PRUnichar* aString,PRInt32 aLength=-1);
@@ -895,6 +896,7 @@ class NS_COM NS_ConvertUCS2toUTF8
     */
   {
     public:
+      explicit
       NS_ConvertUCS2toUTF8( const PRUnichar* aString )
         {
           Init( aString, ~PRUint32(0) /* MAXINT */);
@@ -905,6 +907,7 @@ class NS_COM NS_ConvertUCS2toUTF8
           Init( aString, aLength );
         }
 
+      explicit
       NS_ConvertUCS2toUTF8( PRUnichar aChar )
         {
           Init( &aChar, 1 );
@@ -939,7 +942,7 @@ class NS_COM NS_ConvertUCS2toUTF8
  ***************************************************************/
 class NS_COM nsSubsumeCStr : public nsCString {
 public:
-  nsSubsumeCStr(nsStr& aString);
+  explicit nsSubsumeCStr(nsStr& aString);
   nsSubsumeCStr(PRUnichar* aString,PRBool assumeOwnership,PRInt32 aLength=-1);
   nsSubsumeCStr(char* aString,PRBool assumeOwnership,PRInt32 aLength=-1);
 
diff --git a/mozilla/xpcom/string/obsolete/nsString2.h b/mozilla/xpcom/string/obsolete/nsString2.h
index cec472b57ec..e4c5750a165 100644
--- a/mozilla/xpcom/string/obsolete/nsString2.h
+++ b/mozilla/xpcom/string/obsolete/nsString2.h
@@ -104,9 +104,9 @@ public:
   nsString(const nsString& aString);   
 
 #ifdef NEW_STRING_APIS
-  nsString(const nsAReadableString&);
+  explicit nsString(const nsAReadableString&);
 
-  nsString(const PRUnichar*);
+  explicit nsString(const PRUnichar*);
   nsString(const PRUnichar*, PRInt32);
 #else
   /**
@@ -924,11 +924,11 @@ public:
     virtual ~nsAutoString();
     nsAutoString();
     nsAutoString(const nsAutoString& aString);
-    nsAutoString(const nsString& aString);
-    nsAutoString(const PRUnichar* aString);
+    explicit nsAutoString(const nsString& aString);
+    explicit nsAutoString(const PRUnichar* aString);
     nsAutoString(const PRUnichar* aString,PRInt32 aLength);
-    nsAutoString(PRUnichar aChar);
-    nsAutoString(const CBufDescriptor& aBuffer);    
+    explicit nsAutoString(PRUnichar aChar);
+    explicit nsAutoString(const CBufDescriptor& aBuffer);    
 
 #ifndef NEW_STRING_APIS
 //  nsAutoString(const char* aCString,PRInt32 aLength=-1);
@@ -979,15 +979,15 @@ class NS_COM NS_ConvertASCIItoUCS2
     */
   {
     public:
-      NS_ConvertASCIItoUCS2( const char* );
+      explicit NS_ConvertASCIItoUCS2( const char* );
       NS_ConvertASCIItoUCS2( const char*, PRUint32 );
-      NS_ConvertASCIItoUCS2( char );
+      explicit NS_ConvertASCIItoUCS2( char );
 #if 0
 #ifdef NEW_STRING_APIS
-      NS_ConvertASCIItoUCS2( const nsAReadableCString& );
+      explicit NS_ConvertASCIItoUCS2( const nsAReadableCString& );
 #else
       class nsCString;
-      NS_ConvertASCIItoUCS2( const nsCString& );
+      explicit NS_ConvertASCIItoUCS2( const nsCString& );
 #endif
 #endif
 
@@ -997,6 +997,7 @@ class NS_COM NS_ConvertASCIItoUCS2
           return GetUnicode();
         }
 
+        // is this really a good idea?  I'm getting very paranoid about automatic conversions
       operator nsLiteralString() const
         {
           return nsLiteralString(mUStr, mLength);
@@ -1035,6 +1036,7 @@ class NS_COM NS_ConvertUTF8toUCS2
       : public nsAutoString
   {
     public:
+      explicit
       NS_ConvertUTF8toUCS2( const char* aCString )
         {
           Init( aCString, ~PRUint32(0) /* MAXINT */ );
@@ -1045,6 +1047,7 @@ class NS_COM NS_ConvertUTF8toUCS2
           Init( aCString, aLength );
         }
 
+      explicit
       NS_ConvertUTF8toUCS2( char aChar )
         {
           Init( &aChar, 1 );
@@ -1078,7 +1081,7 @@ class NS_COM NS_ConvertUTF8toUCS2
 class NS_COM nsSubsumeStr : public nsString {
 public:
   nsSubsumeStr();
-  nsSubsumeStr(nsStr& aString);
+  explicit nsSubsumeStr(nsStr& aString);
   nsSubsumeStr(PRUnichar* aString,PRBool assumeOwnership,PRInt32 aLength=-1);
   nsSubsumeStr(char* aString,PRBool assumeOwnership,PRInt32 aLength=-1);
   int Subsume(PRUnichar* aString,PRBool assumeOwnership,PRInt32 aLength=-1);