Previously, extended cell data was never reduced in size even when the

cell was overwritten. With a large history this can be a substantial
amount of memory. To reduce this, compact each extended cell list to
only cells in use as it is scrolled off the visible screen into the
history. From Dan Aloni in GitHub issue 1062.

1 files changed, 43 insertions, 0 deletions

diff --git a/grid.c b/grid.c
index 62ec3f1c..c26db476 100644
--- a/grid.c
+++ b/grid.c
@@ -94,6 +94,48 @@ grid_need_extended_cell(const struct grid_cell_entry *gce,
 	return (0);
 }
 
+/* Free up unused extended cells. */
+static void
+grid_compact_line(struct grid_line *gl)
+{
+	int			 new_extdsize = 0;
+	struct grid_cell	*new_extddata;
+	struct grid_cell_entry	*gce;
+	struct grid_cell	*gc;
+	u_int			 px, idx;
+
+	if (gl->extdsize == 0)
+		return;
+
+	for (px = 0; px < gl->cellsize; px++) {
+		gce = &gl->celldata[px];
+		if (gce->flags & GRID_FLAG_EXTENDED)
+			new_extdsize++;
+	}
+
+	if (new_extdsize == 0) {
+		free(gl->extddata);
+		gl->extddata = NULL;
+		gl->extdsize = 0;
+		return;
+	}
+	new_extddata = xreallocarray(NULL, new_extdsize, sizeof *gl->extddata);
+
+	idx = 0;
+	for (px = 0; px < gl->cellsize; px++) {
+		gce = &gl->celldata[px];
+		if (gce->flags & GRID_FLAG_EXTENDED) {
+			gc = &gl->extddata[gce->offset];
+			memcpy(&new_extddata[idx], gc, sizeof *gc);
+			gce->offset = idx++;
+		}
+	}
+
+	free(gl->extddata);
+	gl->extddata = new_extddata;
+	gl->extdsize = new_extdsize;
+}
+
 /* Set cell as extended. */
 static struct grid_cell *
 grid_extended_cell(struct grid_line *gl, struct grid_cell_entry *gce,
@@ -285,6 +327,7 @@ grid_scroll_history(struct grid *gd, u_int bg)
 	grid_empty_line(gd, yy, bg);
 
 	gd->hscrolled++;
+	grid_compact_line(&gd->linedata[gd->hsize]);
 	gd->hsize++;
 }