diff --git a/mozilla/widget/src/photon/nsClipboard.cpp b/mozilla/widget/src/photon/nsClipboard.cpp
index 4e72cbe50a9..489846414d2 100644
--- a/mozilla/widget/src/photon/nsClipboard.cpp
+++ b/mozilla/widget/src/photon/nsClipboard.cpp
@@ -560,7 +560,7 @@ nsClipboard::HasDataMatchingFlavors(nsISupportsArray* aFlavorList,
 
 nsresult nsClipboard::GetFormat(const char* aMimeStr, char *format ) 
 {
- 	nsCAutoString mimeStr ( CBufDescriptor(NS_CONST_CAST(char*,aMimeStr), PR_TRUE, PL_strlen(aMimeStr)+1) );
+ 	nsDependentCString mimeStr(aMimeStr);
 	int ret = NS_OK;
 
  	if( mimeStr.Equals(kUnicodeMime) || mimeStr.Equals(kTextMime) )
diff --git a/mozilla/xpcom/string/obsolete/nsString.cpp b/mozilla/xpcom/string/obsolete/nsString.cpp
index 72797f743f8..3ac7f6b89c8 100644
--- a/mozilla/xpcom/string/obsolete/nsString.cpp
+++ b/mozilla/xpcom/string/obsolete/nsString.cpp
@@ -74,6 +74,14 @@ nsCString::nsCString()  {
   nsStrPrivate::Initialize(*this,eOneByte);
 }
 
+inline
+nsCString::nsCString(char* aCString, PRUint32 aCapacity, PRUint32 aLength,
+                     eCharSize aCharSize, PRBool aOwnsBuffer) {
+  nsStrPrivate::Initialize(*this, aCString, aCapacity, aLength, aCharSize,
+                           aOwnsBuffer);
+}
+
+
 nsCString::nsCString(const char* aCString) {  
   nsStrPrivate::Initialize(*this,eOneByte);
   Assign(aCString);
@@ -1193,26 +1201,29 @@ NS_LossyConvertUTF16toASCII::NS_LossyConvertUTF16toASCII( const nsAString& aStri
  * Default constructor
  *
  */
-nsCAutoString::nsCAutoString() : nsCString(){
-  nsStrPrivate::Initialize(*this,mBuffer,sizeof(mBuffer)-1,0,eOneByte,PR_FALSE);
+nsCAutoString::nsCAutoString()
+  : nsCString(mBuffer,sizeof(mBuffer)-1,0,eOneByte,PR_FALSE)
+{
   AddNullTerminator(*this);
-
 }
 
-nsCAutoString::nsCAutoString( const nsCString& aString ) : nsCString(){
-  nsStrPrivate::Initialize(*this,mBuffer,sizeof(mBuffer)-1,0,eOneByte,PR_FALSE);
+nsCAutoString::nsCAutoString( const nsCString& aString )
+  : nsCString(mBuffer,sizeof(mBuffer)-1,0,eOneByte,PR_FALSE)
+{
   AddNullTerminator(*this);
   Append(aString);
 }
 
-nsCAutoString::nsCAutoString( const nsACString& aString ) : nsCString(){
-  nsStrPrivate::Initialize(*this,mBuffer,sizeof(mBuffer)-1,0,eOneByte,PR_FALSE);
+nsCAutoString::nsCAutoString( const nsACString& aString )
+  : nsCString(mBuffer,sizeof(mBuffer)-1,0,eOneByte,PR_FALSE)
+{
   AddNullTerminator(*this);
   Append(aString);
 }
 
-nsCAutoString::nsCAutoString(const char* aCString) : nsCString() {
-  nsStrPrivate::Initialize(*this,mBuffer,sizeof(mBuffer)-1,0,eOneByte,PR_FALSE);
+nsCAutoString::nsCAutoString(const char* aCString)
+  : nsCString(mBuffer,sizeof(mBuffer)-1,0,eOneByte,PR_FALSE)
+{
   AddNullTerminator(*this);
   Append(aCString);
 }
@@ -1221,8 +1232,9 @@ nsCAutoString::nsCAutoString(const char* aCString) : nsCString() {
  * Copy construct from ascii c-string
  * @param   aCString is a ptr to a 1-byte cstr
  */
-nsCAutoString::nsCAutoString(const char* aCString,PRInt32 aLength) : nsCString() {
-  nsStrPrivate::Initialize(*this,mBuffer,sizeof(mBuffer)-1,0,eOneByte,PR_FALSE);
+nsCAutoString::nsCAutoString(const char* aCString,PRInt32 aLength)
+  : nsCString(mBuffer,sizeof(mBuffer)-1,0,eOneByte,PR_FALSE)
+{
   AddNullTerminator(*this);
   Append(aCString,aLength);
 }
@@ -1231,13 +1243,10 @@ nsCAutoString::nsCAutoString(const char* aCString,PRInt32 aLength) : nsCString()
  * Copy construct using an external buffer descriptor
  * @param   aBuffer -- descibes external buffer
  */
-nsCAutoString::nsCAutoString(const CBufDescriptor& aBuffer) : nsCString() {
-  if(!aBuffer.mBuffer) {
-    nsStrPrivate::Initialize(*this,mBuffer,sizeof(mBuffer)-1,0,eOneByte,PR_FALSE);
-  }
-  else {
-    nsStrPrivate::Initialize(*this,aBuffer.mBuffer,aBuffer.mCapacity,aBuffer.mLength,aBuffer.mCharSize,!aBuffer.mStackBased);
-  }
+nsCAutoString::nsCAutoString(const CBufDescriptor& aBuffer)
+  : nsCString(aBuffer.mBuffer,aBuffer.mCapacity,aBuffer.mLength,aBuffer.mCharSize,!aBuffer.mStackBased)
+{
+  NS_ASSERTION(aBuffer.mBuffer, "null buffer");
   if(!aBuffer.mIsConst)
     AddNullTerminator(*this); //this isn't really needed, but it guarantees that folks don't pass string constants.
 }
diff --git a/mozilla/xpcom/string/obsolete/nsString.h b/mozilla/xpcom/string/obsolete/nsString.h
index ef13a352254..64c780fd883 100644
--- a/mozilla/xpcom/string/obsolete/nsString.h
+++ b/mozilla/xpcom/string/obsolete/nsString.h
@@ -79,6 +79,14 @@ public:
    */
   nsCString();
 
+protected:
+  /**
+   * Constructor for the use of derived classes.
+   */
+  inline nsCString(char* aCString, PRUint32 aCapacity, PRUint32 aLength,
+                   eCharSize aCharSize, PRBool aOwnsBuffer);
+
+public:
   /**
    * This is our copy constructor 
    * @param   reference to another nsCString
diff --git a/mozilla/xpcom/string/obsolete/nsString2.cpp b/mozilla/xpcom/string/obsolete/nsString2.cpp
index 2b87c4d559e..a0f41cd73ff 100644
--- a/mozilla/xpcom/string/obsolete/nsString2.cpp
+++ b/mozilla/xpcom/string/obsolete/nsString2.cpp
@@ -73,6 +73,14 @@ nsString::nsString() {
   nsStrPrivate::Initialize(*this,eTwoByte);
 }
 
+inline
+nsString::nsString(PRUnichar* aString, PRUint32 aCapacity, PRUint32 aLength,
+                   eCharSize aCharSize, PRBool aOwnsBuffer) {
+  nsStrPrivate::Initialize(*this, (char*)aString, aCapacity, aLength,
+                           aCharSize, aOwnsBuffer);
+}
+
+
 nsString::nsString(const PRUnichar* aString) {
   nsStrPrivate::Initialize(*this,eTwoByte);
   Assign(aString);
@@ -1275,13 +1283,15 @@ PRBool nsString::IsASCII(const PRUnichar* aBuffer) {
  * Default constructor
  *
  */
-nsAutoString::nsAutoString() : nsString() {
-  nsStrPrivate::Initialize(*this, (char*)mBuffer, (sizeof(mBuffer)/sizeof(mBuffer[0]))-1, 0, eTwoByte, PR_FALSE);
+nsAutoString::nsAutoString()
+  : nsString(mBuffer, NS_ARRAY_LENGTH(mBuffer)-1, 0, eTwoByte, PR_FALSE)
+{
   AddNullTerminator(*this);
 }
 
-nsAutoString::nsAutoString(const PRUnichar* aString) : nsString() {
-  nsStrPrivate::Initialize(*this, (char*)mBuffer, (sizeof(mBuffer)/sizeof(mBuffer[0]))-1, 0, eTwoByte, PR_FALSE);
+nsAutoString::nsAutoString(const PRUnichar* aString)
+  : nsString(mBuffer, NS_ARRAY_LENGTH(mBuffer)-1, 0, eTwoByte, PR_FALSE)
+{
   AddNullTerminator(*this);
   Append(aString);
 }
@@ -1291,24 +1301,23 @@ nsAutoString::nsAutoString(const PRUnichar* aString) : nsString() {
  * @param   aString is a ptr to a unistr
  * @param   aLength tells us how many chars to copy from aString
  */
-nsAutoString::nsAutoString(const PRUnichar* aString,PRInt32 aLength) : nsString() {
-  nsStrPrivate::Initialize(*this, (char*)mBuffer, (sizeof(mBuffer)/sizeof(mBuffer[0]))-1, 0, eTwoByte, PR_FALSE);
+nsAutoString::nsAutoString(const PRUnichar* aString,PRInt32 aLength)
+  : nsString(mBuffer, NS_ARRAY_LENGTH(mBuffer)-1, 0, eTwoByte, PR_FALSE)
+{
   AddNullTerminator(*this);
   Append(aString,aLength);
 }
 
 nsAutoString::nsAutoString( const nsString& aString )
-  : nsString()
+  : nsString(mBuffer, NS_ARRAY_LENGTH(mBuffer)-1, 0, eTwoByte, PR_FALSE)
 {
-  nsStrPrivate::Initialize(*this, (char*)mBuffer, (sizeof(mBuffer)/sizeof(mBuffer[0]))-1, 0, eTwoByte, PR_FALSE);
   AddNullTerminator(*this);
   Append(aString);
 }
 
 nsAutoString::nsAutoString( const nsAString& aString )
-  : nsString()
+  : nsString(mBuffer, NS_ARRAY_LENGTH(mBuffer)-1, 0, eTwoByte, PR_FALSE)
 {
-  nsStrPrivate::Initialize(*this, (char*)mBuffer, (sizeof(mBuffer)/sizeof(mBuffer[0]))-1, 0, eTwoByte, PR_FALSE);
   AddNullTerminator(*this);
   Append(aString);
 }
@@ -1319,13 +1328,12 @@ nsAutoString::nsAutoString( const nsAString& aString )
  * constructor that uses external buffer
  * @param   aBuffer describes the external buffer
  */
-nsAutoString::nsAutoString(const CBufDescriptor& aBuffer) : nsString() {
-  if(!aBuffer.mBuffer) {
-    nsStrPrivate::Initialize(*this, (char*)mBuffer, (sizeof(mBuffer)/sizeof(mBuffer[0]))-1, 0, eTwoByte, PR_FALSE);
-  }
-  else {
-    nsStrPrivate::Initialize(*this, aBuffer.mBuffer, aBuffer.mCapacity, aBuffer.mLength, aBuffer.mCharSize, !aBuffer.mStackBased);
-  }
+nsAutoString::nsAutoString(const CBufDescriptor& aBuffer)
+  : nsString(NS_REINTERPRET_CAST(PRUnichar*,aBuffer.mBuffer),
+             aBuffer.mCapacity, aBuffer.mLength, aBuffer.mCharSize,
+             !aBuffer.mStackBased)
+{
+  NS_ASSERTION(aBuffer.mBuffer, "null buffer");
   if(!aBuffer.mIsConst)
     AddNullTerminator(*this);
 }
@@ -1455,8 +1463,9 @@ NS_ConvertUTF8toUTF16::Init( const char* aCString, PRUint32 aLength )
 /**
  * Default copy constructor
  */
-nsAutoString::nsAutoString(const nsAutoString& aString) : nsString() {
-  nsStrPrivate::Initialize(*this,(char*)mBuffer,(sizeof(mBuffer)/sizeof(mBuffer[0]))-1,0,eTwoByte,PR_FALSE);
+nsAutoString::nsAutoString(const nsAutoString& aString)
+  : nsString(mBuffer,NS_ARRAY_LENGTH(mBuffer)-1,0,eTwoByte,PR_FALSE)
+{
   AddNullTerminator(*this);
   Append(aString);
 }
@@ -1466,8 +1475,9 @@ nsAutoString::nsAutoString(const nsAutoString& aString) : nsString() {
  * Copy construct from a unichar
  * @param   
  */
-nsAutoString::nsAutoString(PRUnichar aChar) : nsString(){
-  nsStrPrivate::Initialize(*this,(char*)mBuffer,(sizeof(mBuffer)/sizeof(mBuffer[0]))-1,0,eTwoByte,PR_FALSE);
+nsAutoString::nsAutoString(PRUnichar aChar)
+  : nsString(mBuffer,NS_ARRAY_LENGTH(mBuffer)-1,0,eTwoByte,PR_FALSE)
+{
   AddNullTerminator(*this);
   Append(aChar);
 }
diff --git a/mozilla/xpcom/string/obsolete/nsString2.h b/mozilla/xpcom/string/obsolete/nsString2.h
index 9f766ea0333..bb0a35f91eb 100644
--- a/mozilla/xpcom/string/obsolete/nsString2.h
+++ b/mozilla/xpcom/string/obsolete/nsString2.h
@@ -109,6 +109,15 @@ public:
    */
   nsString();
 
+protected:
+  /**
+   * Constructor for the use of derived classes.
+   */
+  inline nsString(PRUnichar* aString, PRUint32 aCapacity, PRUint32 aLength,
+                  eCharSize aCharSize, PRBool aOwnsBuffer);
+
+public:
+
   /**
    * This is our copy constructor 
    * @param   reference to another nsString