[vte] widget: Store dirty rectangles directly

[Christian Persch <chpe src gnome org>]

commit 379891460a69936260b0e5de90e1f264d9f32264
Author: Christian Persch <chpe gnome org>
Date:   Tue Dec 22 22:47:13 2015 +0100

    widget: Store dirty rectangles directly
    
    Each cairo_region_t in the m_update_regions list was created to contain
    only one rectangle. To be more efficient, simply store the dirty rectangles
    in an array and create the region from it only when doing the invalidate.

 src/vte.cc         |   62 +++++++++++++++++++++++----------------------------
 src/vteinternal.hh |    5 +--
 2 files changed, 30 insertions(+), 37 deletions(-)
---
diff --git a/src/vte.cc b/src/vte.cc
index 88fe332..1fbf8d5 100644
--- a/src/vte.cc
+++ b/src/vte.cc
@@ -419,9 +419,7 @@ VteTerminalPrivate::invalidate_cells(vte::grid::column_t column_start,
                        rect.x, rect.y, rect.width, rect.height);
 
        if (m_active != NULL) {
-                m_update_regions = g_slist_prepend (
-                                                    m_update_regions,
-                               cairo_region_create_rectangle (&rect));
+                g_array_append_val(m_update_rects, rect);
                /* Wait a bit before doing any invalidation, just in
                 * case updates are coming in really soon. */
                add_update_timeout (m_terminal);
@@ -482,15 +480,14 @@ VteTerminalPrivate::invalidate_all()
         auto allocation = get_allocated_rect();
 
        /* replace invalid regions with one covering the whole terminal */
-       reset_update_regions();
+       reset_update_rects();
        rect.x = rect.y = 0;
        rect.width = allocation.width;
        rect.height = allocation.height;
        m_invalidated_all = TRUE;
 
         if (m_active != NULL) {
-                m_update_regions = g_slist_prepend (NULL,
-                               cairo_region_create_rectangle (&rect));
+                g_array_append_val(m_update_rects, rect);
                /* Wait a bit before doing any invalidation, just in
                 * case updates are coming in really soon. */
                add_update_timeout (m_terminal);
@@ -8013,6 +8010,12 @@ VteTerminalPrivate::VteTerminalPrivate(VteTerminal *t) :
         // FIXMEchpe still necessary?
        gtk_widget_set_redraw_on_allocate(m_widget, FALSE);
 
+        m_invalidated_all = false;
+        m_update_rects = g_array_sized_new(FALSE /* zero terminated */,
+                                           FALSE /* clear */,
+                                           sizeof(cairo_rectangle_int_t),
+                                           32 /* preallocated size */);
+
        /* Set an adjustment for the application to use to control scrolling. */
         m_vadjustment = nullptr;
         m_hadjustment = nullptr;
@@ -8265,7 +8268,7 @@ VteTerminalPrivate::widget_size_allocate(GtkAllocation *allocation)
                                        allocation->height);
                /* Force a repaint if we were resized. */
                if (repaint) {
-                       reset_update_regions();
+                       reset_update_rects();
                        invalidate_all();
                }
        }
@@ -8574,6 +8577,9 @@ VteTerminalPrivate::~VteTerminalPrivate()
         g_signal_handlers_disconnect_matched (gtk_widget_get_settings(m_widget), G_SIGNAL_MATCH_DATA,
                                               0, 0, NULL, NULL,
                                               this);
+
+        /* Update rects */
+        g_array_free(m_update_rects, TRUE /* free segment */);
 }
 
 void
@@ -10557,13 +10563,9 @@ add_update_timeout (VteTerminal *terminal)
 }
 
 void
-VteTerminalPrivate::reset_update_regions()
+VteTerminalPrivate::reset_update_rects()
 {
-       if (m_update_regions) {
-               g_slist_foreach (m_update_regions, (GFunc)cairo_region_destroy, nullptr);
-               g_slist_free(m_update_regions);
-               m_update_regions = nullptr;
-       }
+        g_array_set_size(m_update_rects, 0);
 
        /* The invalidated_all flag also marks whether to skip processing
         * due to the widget being invisible.
@@ -10575,7 +10577,7 @@ static gboolean
 remove_from_active_list(VteTerminal *terminal)
 {
        if (terminal->pvt->active == NULL ||
-            terminal->pvt->update_regions != NULL)
+            terminal->pvt->m_update_rects->len != 0)
                 return FALSE;
 
         _vte_debug_print(VTE_DEBUG_TIMEOUT, "Removing terminal from active list\n");
@@ -10607,7 +10609,7 @@ vte_terminal_stop_processing (VteTerminal *terminal)
 static void
 remove_update_timeout (VteTerminal *terminal)
 {
-       terminal->pvt->reset_update_regions();
+       terminal->pvt->reset_update_rects();
         vte_terminal_stop_processing(terminal);
 }
 
@@ -10862,43 +10864,35 @@ process_timeout (gpointer data)
 static gboolean
 update_regions (VteTerminal *terminal)
 {
-       GSList *l;
-       cairo_region_t *region;
        GdkWindow *window;
 
         if (G_UNLIKELY(!terminal->pvt->widget_realized()))
                 return FALSE;
        if (terminal->pvt->visibility_state == GDK_VISIBILITY_FULLY_OBSCURED) {
-               terminal->pvt->reset_update_regions();
+               terminal->pvt->reset_update_rects();
                return FALSE;
        }
 
-       if (G_UNLIKELY (!terminal->pvt->update_regions))
+       if (G_UNLIKELY (!terminal->pvt->m_update_rects->len))
                return FALSE;
 
-
-       l = terminal->pvt->update_regions;
-       if (g_slist_next (l) != NULL) {
-               /* amalgamate into one super-region */
-               region = cairo_region_create ();
-               do {
-                        cairo_region_t *r = (cairo_region_t *)l->data;
-                       cairo_region_union (region, r);
-                       cairo_region_destroy (r);
-               } while ((l = g_slist_next (l)) != NULL);
-       } else {
-               region = (cairo_region_t *)l->data;
+        auto region = cairo_region_create();
+        auto n_rects = terminal->pvt->m_update_rects->len;
+        for (guint i = 0; i < n_rects; i++) {
+                cairo_rectangle_int_t *rect = &g_array_index(terminal->pvt->m_update_rects, 
cairo_rectangle_int_t, i);
+                cairo_region_union_rectangle(region, rect);
        }
-       g_slist_free (terminal->pvt->update_regions);
-       terminal->pvt->update_regions = NULL;
+        g_array_set_size(terminal->pvt->m_update_rects, 0);
+
        terminal->pvt->invalidated_all = FALSE;
 
        /* and perform the merge with the window visible area */
        window = gtk_widget_get_window (&terminal->widget);
        gdk_window_invalidate_region (window, region, FALSE);
-       gdk_window_process_updates (window, FALSE);
        cairo_region_destroy (region);
 
+       gdk_window_process_updates (window, FALSE);
+
        _vte_debug_print (VTE_DEBUG_WORK, "-");
 
        return TRUE;
diff --git a/src/vteinternal.hh b/src/vteinternal.hh
index 0defff0..e7678df 100644
--- a/src/vteinternal.hh
+++ b/src/vteinternal.hh
@@ -220,7 +220,7 @@ public:
        struct _vte_iso2022_state *iso2022;
        _vte_incoming_chunk_t *incoming;/* pending bytestream */
        GArray *pending;                /* pending characters */
-       GSList *update_regions;
+       GArray *m_update_rects;         /* dirty rectangles */
        gboolean invalidated_all;       /* pending refresh of entire terminal */
        GList *active;                  /* is the terminal processing data */
        glong input_bytes;
@@ -480,7 +480,7 @@ public:
         void invalidate_selection();
         void invalidate_all();
 
-        void reset_update_regions();
+        void reset_update_rects();
 
         gssize get_preedit_width(bool left_only);
         gssize get_preedit_length(bool left_only);
@@ -990,7 +990,6 @@ public:
 #define m_char_width char_width
 #define m_char_height char_height
 #define m_active active
-#define m_update_regions update_regions
 #define m_draw draw
 #define m_cursor_blinks cursor_blinks
 #define m_cursor_visible cursor_visible