Bug fix 91250:

Adding a return Boolean from nsIFontEnumerator::UpdateFontList()
to identify if the font lang group has changed from
receiving the WM_FONTCHANGE msg.
/r=rbs;/sr=brendan

gfx/idl/nsIFontEnumerator.idl

@@ -55,7 +55,7 @@ interface nsIFontEnumerator : nsISupports
 
   /* 
    * update the global font list
-   * @param None
+   * return true if font list is changed
    */
-  void UpdateFontList();
+  boolean updateFontList();
 };

gfx/src/beos/nsFontMetricsBeOS.cpp

@@ -468,8 +468,9 @@ nsFontEnumeratorBeOS::HaveFontFor(const char* aLangGroup, PRBool* aResult)
 }
 
 NS_IMETHODIMP
-nsFontEnumeratorBeOS::UpdateFontList()
+nsFontEnumeratorBeOS::UpdateFontList(PRBool *updateFontList)
 {
-  return NS_ERROR_NOT_IMPLEMENTED;
+  *updateFontList = PR_FALSE; // always return false for now
+  return NS_OK;
 }
 

gfx/src/gtk/nsFontMetricsGTK.cpp

@@ -4199,7 +4199,8 @@ nsFontEnumeratorGTK::HaveFontFor(const char* aLangGroup, PRBool* aResult)
 }
 
 NS_IMETHODIMP
-nsFontEnumeratorGTK::UpdateFontList()
+nsFontEnumeratorGTK::UpdateFontList(PRBool *updateFontList)
 {
-  return NS_ERROR_NOT_IMPLEMENTED;
+  *updateFontList = PR_FALSE; // always return false for now
+  return NS_OK;
 }

gfx/src/mac/nsDeviceContextMac.cpp

@@ -1238,7 +1238,8 @@ nsFontEnumeratorMac::HaveFontFor(const char* aLangGroup,PRBool* aResult)
 }
 
 NS_IMETHODIMP
-nsFontEnumeratorMac::UpdateFontList()
+nsFontEnumeratorMac::UpdateFontList(PRBool *updateFontList)
 {
-  return NS_ERROR_NOT_IMPLEMENTED;
+  *updateFontList = PR_FALSE; // always return false for now
+  return NS_OK;
 }

gfx/src/os2/nsFontMetricsOS2.cpp

@@ -1516,8 +1516,9 @@ nsFontEnumeratorOS2::HaveFontFor(const char* aLangGroup, PRBool* aResult)
 }
 
 NS_IMETHODIMP
-nsFontEnumeratorOS2::UpdateFontList()
+nsFontEnumeratorOS2::UpdateFontList(PRBool *updateFontList)
 {
-  return NS_ERROR_NOT_IMPLEMENTED;
+  *updateFontList = PR_FALSE; // always return false for now
+  return NS_OK;
 }
 

gfx/src/photon/nsFontMetricsPh.cpp

@@ -586,7 +586,8 @@ NS_IMETHODIMP
 }
 
 NS_IMETHODIMP
-   nsFontEnumeratorPh::UpdateFontList()
+   nsFontEnumeratorPh::UpdateFontList(PRBool *updateFontList)
 {
-	return NS_ERROR_NOT_IMPLEMENTED;
+  *updateFontList = PR_FALSE; // always return false for now
+  return NS_OK;
 }

gfx/src/qt/nsFontMetricsQT.cpp

@@ -2180,8 +2180,9 @@ nsFontEnumeratorQT::HaveFontFor(const char *aLangGroup,PRBool *aResult)
 }
 
 NS_IMETHODIMP
-nsFontEnumeratorQT::UpdateFontList()
+nsFontEnumeratorQT::UpdateFontList(PRBool *updateFontList)
 {
-  return NS_ERROR_NOT_IMPLEMENTED;
+  *updateFontList = PR_FALSE; // always return false for now
+  return NS_OK;
 }
 

gfx/src/windows/nsFontMetricsWin.cpp

@@ -4710,8 +4710,24 @@ nsFontEnumeratorWin::HaveFontFor(const char* aLangGroup, PRBool* aResult)
 }
 
 NS_IMETHODIMP
-nsFontEnumeratorWin::UpdateFontList()
+nsFontEnumeratorWin::UpdateFontList(PRBool *updateFontList)
 {
+  PRBool haveFontForLang = PR_FALSE;
+  int charSetCounter = 0;
+  PRUint16 maskBitBefore = 0;
+
+  // initialize updateFontList
+  *updateFontList = PR_FALSE;
+
+  // iterate langGoup; skip DEFAULT
+  for (charSetCounter = 1; charSetCounter < eCharSet_COUNT; charSetCounter++) {
+    HaveFontFor(gCharSetInfo[charSetCounter].mLangGroup, &haveFontForLang);
+    if (haveFontForLang)  {
+      maskBitBefore |= PR_BIT(charSetCounter);
+      haveFontForLang = PR_FALSE;
+    }
+  }
+  
   // delete gGlobalFont
   if (nsFontMetricsWin::gGlobalFonts) {
     for (int i = 0; i < nsFontMetricsWin::gGlobalFontsCount; i++) {
@@ -4732,5 +4748,17 @@ nsFontEnumeratorWin::UpdateFontList()
   }
   ::ReleaseDC(nsnull, dc);
   
+  PRUint16 maskBitAfter = 0;
+  // iterate langGoup again; skip DEFAULT
+  for (charSetCounter = 1; charSetCounter < eCharSet_COUNT; charSetCounter++) {
+    HaveFontFor(gCharSetInfo[charSetCounter].mLangGroup, &haveFontForLang);
+    if (haveFontForLang)  {
+      maskBitAfter |= PR_BIT(charSetCounter);
+      haveFontForLang = PR_FALSE;
+    }
+  }
+
+  // check for change
+  *updateFontList = (maskBitBefore != maskBitAfter);
   return NS_OK;
 }

gfx/src/xlib/nsFontMetricsXlib.cpp

@@ -4319,8 +4319,9 @@ nsFontEnumeratorXlib::HaveFontFor(const char* aLangGroup, PRBool* aResult)
 }
 
 NS_IMETHODIMP
-nsFontEnumeratorXlib::UpdateFontList()
+nsFontEnumeratorXlib::UpdateFontList(PRBool *updateFontList)
 {
-  return NS_ERROR_NOT_IMPLEMENTED;
+  *updateFontList = PR_FALSE; // always return false for now
+  return NS_OK;
 }
 

layout/base/nsPresContext.cpp

@@ -450,15 +450,6 @@ nsPresContext::PreferenceChanged(const char* aPrefName)
       return;
   }
 
-  // XXX for WM_FONTCHANGE messages, only flush the font cache (bug=89493)
- //     because nsObjectFrame can't handle a reframe at this time              
-  if (strcmp(aPrefName,"font.internaluseonly.changed") == 0) {
-    if (mDeviceContext) {
-      mDeviceContext->FlushFontCache();
-    }
-    return;
-  }
-
   // Initialize our state from the user preferences
   GetUserPreferences();
 

layout/base/src/nsPresContext.cpp

@@ -450,15 +450,6 @@ nsPresContext::PreferenceChanged(const char* aPrefName)
       return;
   }
 
-  // XXX for WM_FONTCHANGE messages, only flush the font cache (bug=89493)
- //     because nsObjectFrame can't handle a reframe at this time              
-  if (strcmp(aPrefName,"font.internaluseonly.changed") == 0) {
-    if (mDeviceContext) {
-      mDeviceContext->FlushFontCache();
-    }
-    return;
-  }
-
   // Initialize our state from the user preferences
   GetUserPreferences();
 

widget/src/windows/nsWindow.cpp

@@ -2998,24 +2998,27 @@ PRBool nsWindow::ProcessMessage(UINT msg, WPARAM wParam, LPARAM lParam, LRESULT
         case WM_FONTCHANGE: 
           {
             nsresult rv;
+            PRBool didChange = PR_FALSE;
 
             // update the global font list
             nsCOMPtr<nsIFontEnumerator> fontEnum = do_GetService("@mozilla.org/gfx/fontenumerator;1", &rv);
             if (NS_SUCCEEDED(rv)) {
-              fontEnum->UpdateFontList();
-            }
-
-            // update device context font cache
-            // Dirty but easiest way: 
-            // Changing nsIPref entry which triggers callbacks
-            // and flows into calling mDeviceContext->FlushFontCache()
-            // to update the font cache in all the instance of Browsers
-            nsCOMPtr<nsIPref> pPrefs = do_GetService(NS_PREF_CONTRACTID, &rv); 
-            if (NS_SUCCEEDED(rv)) { 
-              PRBool fontInternalChange = PR_FALSE;  
-              pPrefs->GetBoolPref("font.internaluseonly.changed", &fontInternalChange);
-              pPrefs->SetBoolPref("font.internaluseonly.changed", !fontInternalChange);
-            }
+              fontEnum->UpdateFontList(&didChange);
+              //didChange is TRUE only if new font langGroup is added to the list.
+              if (didChange)  {
+                // update device context font cache
+                // Dirty but easiest way: 
+                // Changing nsIPref entry which triggers callbacks
+                // and flows into calling mDeviceContext->FlushFontCache()
+                // to update the font cache in all the instance of Browsers
+                nsCOMPtr<nsIPref> pPrefs = do_GetService(NS_PREF_CONTRACTID, &rv); 
+                if (NS_SUCCEEDED(rv)) { 
+                  PRBool fontInternalChange = PR_FALSE;  
+                  pPrefs->GetBoolPref("font.internaluseonly.changed", &fontInternalChange);
+                  pPrefs->SetBoolPref("font.internaluseonly.changed", !fontInternalChange);
+                }
+              }
+            } //if (NS_SUCCEEDED(rv))
           }
           break;