From fb33fcb370fb58c4aeefbf897785b59b919c7f61 Mon Sep 17 00:00:00 2001
From: Hermet Park <chuneon.park@samsung.com>
Date: Mon, 27 Jul 2020 14:27:52 +0900
Subject: [PATCH] canvas engine: ++safety code

added null checking, no logical changes.
---
 .../engines/software_generic/evas_engine.c    | 90 ++++++++++---------
 1 file changed, 46 insertions(+), 44 deletions(-)

diff --git a/src/modules/evas/engines/software_generic/evas_engine.c b/src/modules/evas/engines/software_generic/evas_engine.c
index aca24c4936..3d6a7f19b3 100644
--- a/src/modules/evas/engines/software_generic/evas_engine.c
+++ b/src/modules/evas/engines/software_generic/evas_engine.c
@@ -3975,58 +3975,60 @@ _smart_merge(Tilebuf *tb, Tilebuf_Rect *rects)
    box = region_rects(region);
    n = region_rects_num(region);
    merged = calloc(1, n * sizeof(Tilebuf_Rect));
-   j = 0;
+   if (merged) {
+        j = 0;
 #if 1
-   // regions sometimes produce box sets like:
-   // +---+
-   // |   |
-   // +---+    +-------+
-   // |   |    |       |
-   // +---+    +-------+---------+
-   //          |                 |
-   //          |                 |
-   //          +-----------------+
-   // so the upper-left 2 boxes can be merged into 1 and they have the same
-   // x coords and are flush-aligned one above the other. that is what
-   // this does - find these and merge them to have fewer rects
-   for (i = 0; i < n; i++)
-     {
-        // skip empty boxes
-        if (box[i].x1 == box[i].x2) continue;
-        // walk all following boxes after this and see if they can be merged
-        // into box i
-        for (k = i + 1; k < n; k++)
+        // regions sometimes produce box sets like:
+        // +---+
+        // |   |
+        // +---+    +-------+
+        // |   |    |       |
+        // +---+    +-------+---------+
+        //          |                 |
+        //          |                 |
+        //          +-----------------+
+        // so the upper-left 2 boxes can be merged into 1 and they have the same
+        // x coords and are flush-aligned one above the other. that is what
+        // this does - find these and merge them to have fewer rects
+        for (i = 0; i < n; i++)
           {
-             // skip empty boxes after i
-             if (box[k].x1 == box[k].x2) continue;
-             // match x coords
-             if ((box[i].x1 == box[k].x1) && // if aligned vertically
-                 (box[i].x2 == box[k].x2))   // exactly above/below
+             // skip empty boxes
+             if (box[i].x1 == box[i].x2) continue;
+             // walk all following boxes after this and see if they can be merged
+             // into box i
+             for (k = i + 1; k < n; k++)
                {
-                  // right below, or right above
-                  if (box[i].y2 == box[k].y1) // this box flush below
+                  // skip empty boxes after i
+                  if (box[k].x1 == box[k].x2) continue;
+                  // match x coords
+                  if ((box[i].x1 == box[k].x1) && // if aligned vertically
+                      (box[i].x2 == box[k].x2))   // exactly above/below
                     {
-                       box[i].y2 = box[k].y2; // merge below i
-                       box[k].x2 = box[k].x1; // empty this box - merged
-                    }
-                  else if (box[i].y1 == box[k].y2) // this box flush above
-                    {
-                       box[i].y2 = box[k].y2; // merge above i
-                       box[k].x2 = box[k].x1; // empty this box - merged
+                       // right below, or right above
+                       if (box[i].y2 == box[k].y1) // this box flush below
+                         {
+                            box[i].y2 = box[k].y2; // merge below i
+                            box[k].x2 = box[k].x1; // empty this box - merged
+                         }
+                       else if (box[i].y1 == box[k].y2) // this box flush above
+                         {
+                            box[i].y2 = box[k].y2; // merge above i
+                            box[k].x2 = box[k].x1; // empty this box - merged
+                         }
                     }
                }
+             // i may have expanded but will not be empty. future boxes after
+             // this may be empty though but handled at top of loop
+             merged[j].x = box[i].x1;
+             merged[j].y = box[i].y1;
+             merged[j].w = box[i].x2 - box[i].x1;
+             merged[j].h = box[i].y2 - box[i].y1;
+             mergelist = (Tilebuf_Rect *)eina_inlist_append
+                (EINA_INLIST_GET(mergelist), EINA_INLIST_GET(&(merged[j])));
+             j++;
           }
-        // i may have expanded but will not be empty. future boxes after
-        // this may be empty though but handled at top of loop
-        merged[j].x = box[i].x1;
-        merged[j].y = box[i].y1;
-        merged[j].w = box[i].x2 - box[i].x1;
-        merged[j].h = box[i].y2 - box[i].y1;
-        mergelist = (Tilebuf_Rect *)eina_inlist_append
-          (EINA_INLIST_GET(mergelist), EINA_INLIST_GET(&(merged[j])));
-        j++;
-     }
 #endif
+   }
    region_free(region);
    rects = mergelist;