text-progress-bar: Try to be more defensive about text leaksfix-text-spew

We try to prevent text from showing through in the text splash,
by disable dmesg to screen and by redirecting console messages to
a log file.

Still, occasionally a kernel message may leak through.  This
commit tries to harden against that by moving the cursor up to
home when we aren't using it.

3 files changed, 60 insertions, 0 deletions

diff --git a/src/libply-splash-core/ply-text-display.c b/src/libply-splash-core/ply-text-display.c
index 7cabd98f..fcaff22e 100644
--- a/src/libply-splash-core/ply-text-display.c
+++ b/src/libply-splash-core/ply-text-display.c
@@ -58,6 +58,10 @@
 #define MOVE_CURSOR_SEQUENCE "\033[%d;%df"
 #endif
 
+#ifndef SET_TOP_AND_BOTTOM_MARGINS_SEQUENCE
+#define SET_TOP_AND_BOTTOM_MARGINS_SEQUENCE "\033[%d;%dr"
+#endif
+
 #ifndef HIDE_CURSOR_SEQUENCE
 #define HIDE_CURSOR_SEQUENCE "\033[?25l"
 #endif
@@ -70,6 +74,14 @@
 #define COLOR_SEQUENCE_FORMAT "\033[%dm"
 #endif
 
+#ifndef ENABLE_WRAPPING_SEQUENCE
+#define ENABLE_WRAPPING_SEQUENCE "\033[?7h"
+#endif
+
+#ifndef DISABLE_WRAPPING_SEQUENCE
+#define DISABLE_WRAPPING_SEQUENCE "\033[?7l"
+#endif
+
 #ifndef PAUSE_SEQUENCE
 #define PAUSE_SEQUENCE "\023"
 #endif
@@ -148,6 +160,37 @@ ply_text_display_set_cursor_position (ply_text_display_t *display,
 }
 
 void
+ply_text_display_set_scrollable_area (ply_text_display_t *display,
+                                      int                 top_row,
+                                      int                 bottom_row)
+{
+  int number_of_rows;
+
+  number_of_rows = ply_text_display_get_number_of_rows (display);
+
+  top_row = CLAMP (top_row, 0, bottom_row);
+  bottom_row = CLAMP (bottom_row, top_row, number_of_rows - 1);
+
+  ply_terminal_write (display->terminal,
+                      SET_TOP_AND_BOTTOM_MARGINS_SEQUENCE,
+                      top_row, bottom_row);
+}
+
+void
+ply_text_display_enable_wrapping (ply_text_display_t *display)
+{
+  ply_terminal_write (display->terminal,
+                      ENABLE_WRAPPING_SEQUENCE);
+}
+
+void
+ply_text_display_disable_wrapping (ply_text_display_t *display)
+{
+  ply_terminal_write (display->terminal,
+                      DISABLE_WRAPPING_SEQUENCE);
+}
+
+void
 ply_text_display_clear_screen (ply_text_display_t *display)
 {
   if (ply_is_tracing ())
diff --git a/src/libply-splash-core/ply-text-display.h b/src/libply-splash-core/ply-text-display.h
index 3fd7dab2..7f1e20b7 100644
--- a/src/libply-splash-core/ply-text-display.h
+++ b/src/libply-splash-core/ply-text-display.h
@@ -54,6 +54,12 @@ int  ply_text_display_get_number_of_columns (ply_text_display_t *display);
 void ply_text_display_set_cursor_position (ply_text_display_t *display,
                                            int                 column,
                                            int                 row);
+void ply_text_display_set_scrollable_area (ply_text_display_t *display,
+                                           int                 top_row,
+                                           int                 bottom_row);
+void ply_text_display_enable_wrapping (ply_text_display_t *display);
+void ply_text_display_disable_wrapping (ply_text_display_t *display);
+
 __attribute__((__format__ (__printf__, 2, 3)))
 void ply_text_display_write (ply_text_display_t *display,
                              const char         *format,
diff --git a/src/libply-splash-core/ply-text-progress-bar.c b/src/libply-splash-core/ply-text-progress-bar.c
index bf4b3781..852f016b 100644
--- a/src/libply-splash-core/ply-text-progress-bar.c
+++ b/src/libply-splash-core/ply-text-progress-bar.c
@@ -184,6 +184,8 @@ ply_text_progress_bar_draw (ply_text_progress_bar_t *progress_bar)
 
     width = progress_bar->number_of_columns - 2 - strlen (os_string);
 
+    ply_text_display_disable_wrapping (progress_bar->display);
+    ply_text_display_set_scrollable_area (progress_bar->display, 0, progress_bar->row);
     ply_text_display_set_cursor_position (progress_bar->display,
                                           progress_bar->column,
                                           progress_bar->row);
@@ -210,6 +212,7 @@ ply_text_progress_bar_draw (ply_text_progress_bar_t *progress_bar)
 
         ply_text_display_write (progress_bar->display, "%c", ' ');
     }
+    ply_text_display_set_cursor_position (progress_bar->display, 0, 0);
 
     ply_text_display_set_background_color (progress_bar->display,
                                            PLY_TERMINAL_COLOR_BLACK);
@@ -230,10 +233,18 @@ ply_text_progress_bar_draw (ply_text_progress_bar_t *progress_bar)
                                               progress_bar->row);
 
         ply_text_display_write (progress_bar->display, "%s", os_string);
+        ply_text_display_set_cursor_position (progress_bar->display, 0, 0);
 
         ply_text_display_set_foreground_color (progress_bar->display,
                                                PLY_TERMINAL_COLOR_DEFAULT);
     }
+
+    ply_text_display_set_background_color (progress_bar->display,
+                                           PLY_TERMINAL_COLOR_DEFAULT);
+
+    ply_text_display_set_scrollable_area (progress_bar->display, 0, progress_bar->row - 1);
+    ply_text_display_set_cursor_position (progress_bar->display, 0, 0);
+    ply_text_display_enable_wrapping (progress_bar->display);
 }
 
 void