From c558898981a43637a64c17a40fd816ae41991961 Mon Sep 17 00:00:00 2001
From: "jan.nijtmans" <nijtmans@users.sourceforge.net>
Date: Wed, 18 Jan 2017 12:44:22 +0000
Subject: Change more refCount checks to the form "(...refCount-- <= 1)", so no
 separate decrement and compare is necessary. This allows (in the future) the
 same code to work when refCount becomes unsigned (which at least doubles the
 range). No functional change.

---
 generic/tkImgPhInstance.c |  3 +--
 generic/tkText.c          | 12 ++++--------
 generic/tkTextDisp.c      |  9 ++++-----
 generic/tkTextIndex.c     |  2 +-
 generic/tkTextTag.c       |  5 ++---
 generic/tkWindow.c        |  3 +--
 6 files changed, 13 insertions(+), 21 deletions(-)

diff --git a/generic/tkImgPhInstance.c b/generic/tkImgPhInstance.c
index bd152f2..98aaeab 100644
--- a/generic/tkImgPhInstance.c
+++ b/generic/tkImgPhInstance.c
@@ -721,8 +721,7 @@ TkImgPhotoFree(
     PhotoInstance *instancePtr = clientData;
     ColorTable *colorPtr;
 
-    instancePtr->refCount -= 1;
-    if (instancePtr->refCount > 0) {
+    if (instancePtr->refCount-- > 1) {
 	return;
     }
 
diff --git a/generic/tkText.c b/generic/tkText.c
index 412a7f2..6ff1db9 100644
--- a/generic/tkText.c
+++ b/generic/tkText.c
@@ -1570,8 +1570,7 @@ TextWidgetObjCmd(
     }
 
   done:
-    textPtr->refCount--;
-    if (textPtr->refCount == 0) {
+    if (textPtr->refCount-- <= 1) {
 	ckfree(textPtr);
     }
     return result;
@@ -1964,9 +1963,7 @@ DestroyText(
      * portion of the text widget.
      */
 
-    sharedTextPtr->refCount--;
-
-    if (sharedTextPtr->refCount > 0) {
+    if (sharedTextPtr->refCount-- > 1) {
 	TkBTreeRemoveClient(sharedTextPtr->tree, textPtr);
 
 	/*
@@ -2042,13 +2039,12 @@ DestroyText(
     }
 
     textPtr->tkwin = NULL;
-    textPtr->refCount--;
     Tcl_DeleteCommandFromToken(textPtr->interp, textPtr->widgetCmd);
     if (textPtr->afterSyncCmd){
 	Tcl_DecrRefCount(textPtr->afterSyncCmd);
 	textPtr->afterSyncCmd = NULL;
     }
-    if (textPtr->refCount == 0) {
+    if (textPtr->refCount-- <= 1) {
 	ckfree(textPtr);
     }
 }
@@ -5526,7 +5522,7 @@ RunAfterSyncCmd(
 	* The widget has been deleted. Don't do anything.
 	*/
 
-	if (--textPtr->refCount == 0) {
+	if (textPtr->refCount-- <= 1) {
 	    ckfree((char *) textPtr);
 	}
 	return;
diff --git a/generic/tkTextDisp.c b/generic/tkTextDisp.c
index 1be26c4..704d47d 100644
--- a/generic/tkTextDisp.c
+++ b/generic/tkTextDisp.c
@@ -3005,7 +3005,7 @@ AsyncUpdateLineMetrics(
 	 * The widget has been deleted, or is not mapped. Don't do anything.
 	 */
 
-	if (--textPtr->refCount == 0) {
+	if (textPtr->refCount-- <= 1) {
 	    ckfree(textPtr);
 	}
 	return;
@@ -3080,8 +3080,7 @@ AsyncUpdateLineMetrics(
 
         GenerateWidgetViewSyncEvent(textPtr, 1);
 
-	textPtr->refCount--;
-	if (textPtr->refCount == 0) {
+	if (textPtr->refCount-- <= 1) {
 	    ckfree(textPtr);
 	}
 	return;
@@ -4163,7 +4162,7 @@ DisplayText(
 	textPtr->refCount++;
 	dInfoPtr->flags &= ~REPICK_NEEDED;
 	TkTextPickCurrent(textPtr, &textPtr->pickEvent);
-	if (--textPtr->refCount == 0) {
+	if (textPtr->refCount-- <= 1) {
 	    ckfree(textPtr);
 	    goto end;
 	}
@@ -6752,7 +6751,7 @@ AsyncUpdateYScrollbar(
 	GetYView(textPtr->interp, textPtr, 1);
     }
 
-    if (--textPtr->refCount == 0) {
+    if (textPtr->refCount-- <= 1) {
 	ckfree(textPtr);
     }
 }
diff --git a/generic/tkTextIndex.c b/generic/tkTextIndex.c
index d227bd8..faa1afd 100644
--- a/generic/tkTextIndex.c
+++ b/generic/tkTextIndex.c
@@ -87,7 +87,7 @@ FreeTextIndexInternalRep(
     TkTextIndex *indexPtr = GET_TEXTINDEX(indexObjPtr);
 
     if (indexPtr->textPtr != NULL) {
-	if (--indexPtr->textPtr->refCount == 0) {
+	if (indexPtr->textPtr->refCount-- <= 1) {
 	    /*
 	     * The text widget has been deleted and we need to free it now.
 	     */
diff --git a/generic/tkTextTag.c b/generic/tkTextTag.c
index dd3127d..d9329f5 100644
--- a/generic/tkTextTag.c
+++ b/generic/tkTextTag.c
@@ -1258,8 +1258,7 @@ TkTextFreeTag(
 	if (textPtr != tagPtr->textPtr) {
 	    Tcl_Panic("Tag being deleted from wrong widget");
 	}
-	textPtr->refCount--;
-	if (textPtr->refCount == 0) {
+	if (textPtr->refCount-- <= 1) {
 	    ckfree(textPtr);
 	}
 	tagPtr->textPtr = NULL;
@@ -1522,7 +1521,7 @@ TkTextBindProc(
     }
 
   done:
-    if (--textPtr->refCount == 0) {
+    if (textPtr->refCount-- <= 1) {
 	ckfree(textPtr);
     }
 }
diff --git a/generic/tkWindow.c b/generic/tkWindow.c
index 5855b7c..20b4f20 100644
--- a/generic/tkWindow.c
+++ b/generic/tkWindow.c
@@ -1479,8 +1479,7 @@ Tk_DestroyWindow(
 
 	    winPtr->mainPtr->deletionEpoch++;
 	}
-	winPtr->mainPtr->refCount--;
-	if (winPtr->mainPtr->refCount == 0) {
+	if (winPtr->mainPtr->refCount-- <= 1) {
 	    register const TkCmd *cmdPtr;
 
 	    /*
-- 
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