user32: Ignore invalid parameters in DrawTextEx when HDC is invalid.

dlls/user32/tests/text.c

@@ -519,6 +519,38 @@ static void test_DrawTextCalcRect(void)
             ok(textheight==0,"Got textheight from DrawTextExW\n");
             ok(dtp.uiLengthDrawn==1337, "invalid dtp.uiLengthDrawn = %i\n",dtp.uiLengthDrawn);
         }
+
+        /* When passing invalid DC, other parameters must be ignored - no crashes on invalid pointers */
+        SetLastError(0xdeadbeef);
+        textheight = DrawTextExW((HDC)0xdeadbeef, emptystringW, 100000, (LPRECT)0xdeadbeef, 0, 0);
+        ok(textheight == 0, "Got textheight from DrawTextExW\n");
+        ok(GetLastError() == 0xdeadbeef,"Got error %lu\n", GetLastError());
+
+        SetLastError(0xdeadbeef);
+        textheight = DrawTextExW((HDC)0xdeadbeef, (LPWSTR)0xdeadbeef, 100000, &rect, 0, 0);
+        ok(textheight == 0, "Got textheight from DrawTextExW\n");
+        ok(GetLastError() == 0xdeadbeef,"Got error %lu\n", GetLastError());
+
+        SetLastError(0xdeadbeef);
+        textheight = DrawTextExW((HDC)0xdeadbeef, 0, -1, (LPRECT)0xdeadbeef, DT_CALCRECT, 0);
+        ok(textheight == 0, "Got textheight from DrawTextExW\n");
+        ok(GetLastError() == 0xdeadbeef,"Got error %lu\n", GetLastError());
+
+        SetLastError(0xdeadbeef);
+        textheight = DrawTextExA((HDC)0xdeadbeef, emptystring, 100000, (LPRECT)0xdeadbeef, 0, 0);
+        ok(textheight == 0, "Got textheight from DrawTextExA\n");
+        ok(GetLastError() == ERROR_INVALID_PARAMETER || GetLastError() == ERROR_INVALID_HANDLE,"Got error %lu\n", GetLastError());
+
+        SetLastError(0xdeadbeef);
+        textheight = DrawTextExA((HDC)0xdeadbeef, 0, -1, (LPRECT)0xdeadbeef, DT_CALCRECT, 0);
+        ok(textheight == 0, "Got textheight from DrawTextExA\n");
+        ok(GetLastError() == ERROR_INVALID_PARAMETER || GetLastError() == ERROR_INVALID_HANDLE,"Got error %lu\n", GetLastError());
+
+        if (0)
+        {
+            /* Crashes */
+            textheight = DrawTextExA((HDC)0xdeadbeef, (LPSTR)0xdeadbeef, 100, &rect, 0, 0);
+        }
     }
 
     /* More test cases from bug 12226 */

dlls/user32/text.c

@@ -874,8 +874,7 @@ INT WINAPI DrawTextExW( HDC hdc, LPWSTR str, INT i_count,
     int len, lh, count=i_count;
     TEXTMETRICW tm;
     int lmargin = 0, rmargin = 0;
-    int x = rect->left, y = rect->top;
-    int width = rect->right - rect->left;
+    int x, y, width;
     int max_width = 0;
     int last_line;
     int tabwidth /* to keep gcc happy */ = 0;
@@ -897,7 +896,13 @@ INT WINAPI DrawTextExW( HDC hdc, LPWSTR str, INT i_count,
     if (flags & DT_SINGLELINE)
         flags &= ~DT_WORDBREAK;
 
-    GetTextMetricsW(hdc, &tm);
+    if (!GetTextMetricsW(hdc, &tm))
+        return 0;
+
+    x = rect->left;
+    y = rect->top;
+    width = rect->right - rect->left;
+
     if (flags & DT_EXTERNALLEADING)
 	lh = tm.tmHeight + tm.tmExternalLeading;
     else
@@ -1086,18 +1091,24 @@ INT WINAPI DrawTextExA( HDC hdc, LPSTR str, INT count,
    DWORD wmax;
    DWORD amax;
    UINT cp;
+   TEXTMETRICA tm;
+
+   if (!GetTextMetricsA(hdc, &tm))
+   {
+       SetLastError(ERROR_INVALID_HANDLE);
+       return 0;
+   }
 
    if (!count) return 0;
    if (!str && count > 0) return 0;
    if( !str || ((count == -1) && !(count = strlen(str))))
    {
         int lh;
-        TEXTMETRICA tm;
 
         if (dtp && dtp->cbSize != sizeof(DRAWTEXTPARAMS))
             return 0;
 
-        GetTextMetricsA(hdc, &tm);
+
         if (flags & DT_EXTERNALLEADING)
             lh = tm.tmHeight + tm.tmExternalLeading;
         else