bug 183

[lyx.git] / src / BufferView2.C

diff --git a/src/BufferView2.C b/src/BufferView2.C
index 5ed89afe1885cc78d825500005bc7a780c98f788..6072b4548345bb74ee85ee1708d6b4a1bb9f27ec 100644 (file)
--- a/src/BufferView2.C
+++ b/src/BufferView2.C
@@ -117,22 +117,24 @@ bool BufferView::removeAutoInsets()
        bool found = false;
 
        // Trap the deletion of the paragraph the cursor is in.
-       // It should be almost impossible for the new cursor par to be
-       // deleted later on in this function.
-       // This is the way to segfault this now. Although you may have to do this
-       // multiple times: Have an InsetERT with an unknown command in it.
-       // View->DVI, move cursor between Error box and InsetERT and hit <Enter>,
-       // <down-arrow>, <Enter> again, View->DVI, BANG!
-       //
+       // Iterate until we find a paragraph that won't be immediately deleted.
+       // In reality this should mean we only execute the body of the while
+       // loop once at most.  However for safety we iterate rather than just
+       // make this an if() conditional.
        while ((cur_par_prev || cur_par_next)
               && text->setCursor(this,
                                  cur_par_prev ? cur_par_prev : cur_par_next,
                                  0)) {
-               // we just removed cur_par so have to fix the "cursor"
+               // We just removed cur_par so have to fix the "cursor"
                if (cur_par_prev) {
+                       // '.' = cur_par
+                       //  a -> a.
+                       // .
                        cur_par = cur_par_prev;
                        cur_pos = cur_par->size();
                } else {
+                       // .  -> .a
+                       //  a
                        cur_par = cur_par_next;
                        cur_pos = 0;
                }
@@ -147,7 +149,38 @@ bool BufferView::removeAutoInsets()
                Paragraph * par_prev = par ? par->previous() : 0;
                bool removed = false;
 
-               bool dead = text->setCursor(this, par, 0);
+               if (text->setCursor(this, par, 0)
+                   && cur_par == par_prev) {
+                       // The previous setCursor line was deleted and that
+                       // was the cur_par line.  This can only happen if an
+                       // error box was the sole item on cur_par.
+                       if (cur_par_prev) {
+                               // '|' = par, '.' = cur_par, 'E' = error box
+                               // First step below may occur before while{}
+                               //  a    |a      a     a     a.
+                               //  E -> .E -> |.E -> .  -> |b
+                               // .      b      b    |b
+                               //  b
+                               cur_par = cur_par_prev;
+                               cur_pos = cur_par_prev->size();
+                               cur_par_prev = cur_par->previous();
+                               // cur_par_next remains the same 
+                       } else if (cur_par_next) {
+                               // First step below may occur before while{}
+                               // .
+                               //  E -> |.E -> |.  -> . -> .|a
+                               //  a      a      a    |a
+                               cur_par = cur_par_next;
+                               cur_pos = 0;
+                               // cur_par_prev remains unset
+                               cur_par_next = cur_par->next();
+                       } else {
+                               // I can't find a way to trigger this
+                               // so it should be unreachable code
+                               // unless the buffer is corrupted.
+                               lyxerr << "BufferView::removeAutoInsets() is bad\n";
+                       }
+               }
 
                Paragraph::inset_iterator pit = par->inset_iterator_begin();
                Paragraph::inset_iterator pend = par->inset_iterator_end();
@@ -169,40 +202,6 @@ bool BufferView::removeAutoInsets()
                        found = true;
                        text->redoParagraph(this);
                }
-               if (dead) {
-                       // Error box paragraphs appear to have a bad next_ pointer
-                       // especially when that's all that's in the paragraph..
-                       // Then if you are in an empty paragraph after an error box
-                       // which is in its own paragraph this will fail because
-                       // cur_prev_par was the one just deleted (I think).
-                       // That's the main reason why this clause makes almost no difference.
-                       // Feel free to delete this whole clause as my brain is asleep now.
-                       while ((cur_par_prev || cur_par_next)
-                              && text->setCursor(this,
-                                                 cur_par_prev ? cur_par_prev : cur_par_next,
-                                                 0)) {
-                               // we just removed cur_par so have to fix the "cursor"
-                               if (cur_par_prev == par) {
-                                       // attempting to solve the "prev par was deleted
-                                       // because it had only an error inset in it" problem
-                                       if (par_prev) {
-                                               cur_par = par_prev;
-                                               cur_pos = cur_par->size();
-                                       } else {
-                                               cur_par = cur_par_next;
-                                               cur_pos = 0;
-                                       }
-                               } else if (cur_par_prev) {
-                                       cur_par = cur_par_prev;
-                                       cur_pos = cur_par->size();
-                               } else {
-                                       cur_par = cur_par_next;
-                                       cur_pos = 0;
-                               }
-                               cur_par_prev = cur_par->previous();
-                               cur_par_next = cur_par->next();
-                       }
-               }
        }
 
        text->setCursorIntern(this, cur_par, cur_pos);