Attempt to fix #7673 in a more "interesting" way than in branch (where

we will be cautious, of course). The problem was that we were issuing
the Buffer::changed() signal before we did updateBuffer(), and this
caused an inconsistency. The idea here is to defer issuing this signal
until we call processUpdateFlags(). We know we need a redraw if we've
deleted a whole paragraph.

This should work properly, so long as checkDepm is called from within
the dispatch mechanism. There may, however, be other paths, and I've
noted one explicitly with a FIXME in Text2.cpp. I've tested a few
different variations, however, and I haven't seen any problems. But if
we do run into problems, we can go ahead and do the update there that we
were previously doing in checkDepm itself.

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@40352 a592a061-630c-0410-9148-cb99ea01b6c8

src/BufferView.cpp

@@ -2410,7 +2410,7 @@ bool BufferView::checkDepm(Cursor & cur, Cursor & old)
 	d->cursor_ = cur;
 
 	cur.forceBufferUpdate();
-	buffer_.changed(true);
+	cur.screenUpdateFlags(Update::Force);
 	return true;
 }
 

src/Cursor.cpp

@@ -1968,8 +1968,12 @@ bool Cursor::upDownInText(bool up, bool & updateNeeded)
 
 			updateNeeded |= bv().checkDepm(dummy, *this);
 			updateTextTargetOffset();
-			if (updateNeeded)
+			if (updateNeeded) {
 				forceBufferUpdate();
+				// DEPM may have requested a screen update
+				this->screenUpdateFlags(
+					this->screenUpdate() | dummy.screenUpdate());
+			}
 		}
 		return false;
 	}
@@ -1995,6 +1999,7 @@ bool Cursor::upDownInText(bool up, bool & updateNeeded)
 		if (bv().checkDepm(dummy, old)) {
 			updateNeeded = true;
 			// Make sure that cur gets back whatever happened to dummy (Lgb)
+			// This will include any screen update requested by DEPM
 			operator=(dummy);
 		}
 	} else {

src/Cursor.h

@@ -247,6 +247,8 @@ public:
 	 * Not using noScreenUpdate() should never be wrong.
 	 */
 	void noScreenUpdate() const;
+	///
+	Update::flags screenUpdate() const { return disp_.screenUpdate(); }
 	/// fix cursor in circumstances that should never happen.
 	/// \retval true if a fix occured.
 	bool fixIfBroken();

src/Text2.cpp

@@ -535,6 +535,9 @@ bool Text::setCursor(Cursor & cur, pit_type par, pos_type pos,
 	bool const update_needed = !tm.contains(par);
 	Cursor old = cur;
 	setCursorIntern(cur, par, pos, setfont, boundary);
+	// FIXME There is a chance that we'll miss a screen update here.
+	// If so, then do DEPM and then check if cur wants an update and
+	// go ahead and do it, if so.
 	return cur.bv().checkDepm(cur, old) || update_needed;
 }
 

src/Text3.cpp

@@ -630,8 +630,12 @@ void Text::dispatch(Cursor & cur, FuncRequest & cmd)
 				// provide it with two different cursors.
 				Cursor dummy = cur;
 				dummy.pos() = dummy.pit() = 0;
-				if (cur.bv().checkDepm(dummy, cur))
+				if (cur.bv().checkDepm(dummy, cur)) {
 					cur.forceBufferUpdate();
+					// DEPM may have requested a screen update
+					cur.screenUpdateFlags(
+						cur.screenUpdate() | dummy.screenUpdate());
+				}
 			}
 		}
 		break;
@@ -657,8 +661,12 @@ void Text::dispatch(Cursor & cur, FuncRequest & cmd)
 				Cursor dummy = cur;
 				dummy.pos() = cur.lastpos();
 				dummy.pit() = cur.lastpit();
-				if (cur.bv().checkDepm(dummy, cur))
+				if (cur.bv().checkDepm(dummy, cur)) {
 					cur.forceBufferUpdate();
+					// DEPM may have requested a screen update
+					cur.screenUpdateFlags(
+						cur.screenUpdate() | dummy.screenUpdate());
+				}
 			}
 		}
 		break;
@@ -841,8 +849,12 @@ void Text::dispatch(Cursor & cur, FuncRequest & cmd)
 				// provide it with two different cursors.
 				Cursor dummy = cur;
 				dummy.pos() = dummy.pit() = 0;
-				if (cur.bv().checkDepm(dummy, cur))
+				if (cur.bv().checkDepm(dummy, cur)) {
 					cur.forceBufferUpdate();
+					// DEPM may have requested a screen update
+					cur.screenUpdateFlags(
+						cur.screenUpdate() | dummy.screenUpdate());
+				}
 			}
 		}
 		break;
@@ -891,8 +903,12 @@ void Text::dispatch(Cursor & cur, FuncRequest & cmd)
 				Cursor dummy = cur;
 				dummy.pos() = cur.lastpos();
 				dummy.pit() = cur.lastpit();
-				if (cur.bv().checkDepm(dummy, cur))
+				if (cur.bv().checkDepm(dummy, cur)) {
 					cur.forceBufferUpdate();
+					// DEPM may have requested a screen update
+					cur.screenUpdateFlags(
+						cur.screenUpdate() | dummy.screenUpdate());
+				}
 			}
 		}
 		break;