From 635517ca859a12d176e74eb2f15a7393b1b7e2a3 Mon Sep 17 00:00:00 2001
From: Vadim Zeitlin <vadim@wxwidgets.org>
Date: Sun, 27 Apr 2014 22:38:50 +0000
Subject: [PATCH] Make wxMSW wxTextCtrl::AdjustSpaceLimit() safe to call in all
 cases.

Allow calling this function not only from inside DoWriteText(): first, because
the existing code could be doing this (although this is only a concern in 3.0
branch as it was made private in the trunk) and second because it could
actually happen if the text limit was exceeded by user typing in the control.

See #15980.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@76403 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
---
 include/wx/msw/textctrl.h |  8 ++++----
 src/msw/textctrl.cpp      | 18 ++++++++++++++----
 2 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/include/wx/msw/textctrl.h b/include/wx/msw/textctrl.h
index 14265e7983..1a81e44d71 100644
--- a/include/wx/msw/textctrl.h
+++ b/include/wx/msw/textctrl.h
@@ -203,11 +203,11 @@ protected:
     // the limit is due to a previous call to SetMaxLength() and not built in)
     bool HasSpaceLimit(unsigned int *len) const;
 
-    // call this to increase the size limit (will do nothing if the current
-    // limit is big enough)
+    // Used by EN_MAXTEXT handler to increase the size limit (will do nothing
+    // if the current limit is big enough). Should never be called directly.
     //
-    // returns true if we increased the limit to allow entering more text,
-    // false if we hit the limit set by SetMaxLength() and so didn't change it
+    // Returns true if we increased the limit to allow entering more text,
+    // false if we hit the limit set by SetMaxLength() and so didn't change it.
     bool AdjustSpaceLimit();
 
 #if wxUSE_RICHEDIT && (!wxUSE_UNICODE || wxUSE_UNICODE_MSLU)
diff --git a/src/msw/textctrl.cpp b/src/msw/textctrl.cpp
index dfdf2c6e3f..473aa0c36e 100644
--- a/src/msw/textctrl.cpp
+++ b/src/msw/textctrl.cpp
@@ -2149,13 +2149,23 @@ bool wxTextCtrl::AdjustSpaceLimit()
     unsigned int len = ::GetWindowTextLength(GetHwnd());
     if ( len >= limit )
     {
+        unsigned long increaseBy;
+
         // We need to increase the size of the buffer and to avoid increasing
         // it too many times make sure that we make it at least big enough to
-        // fit all the text we are currently inserting into the control.
-        unsigned long increaseBy = gs_lenOfInsertedText.top();
+        // fit all the text we are currently inserting into the control, if
+        // we're inserting any, i.e. if we're called from DoWriteText().
+        if ( !gs_lenOfInsertedText.empty() )
+        {
+            increaseBy = gs_lenOfInsertedText.top();
 
-        // Indicate to the caller that we increased the limit.
-        gs_lenOfInsertedText.top() = -1;
+            // Indicate to the caller that we increased the limit.
+            gs_lenOfInsertedText.top() = -1;
+        }
+        else // Not inserting text, must be text actually typed by user.
+        {
+            increaseBy = 0;
+        }
 
         // But also increase it by at least 32KB chunks -- again, to avoid
         // doing it too often -- and round it up to 32KB in any case.