BufferView: user must call update() after all changes and before vert_iter()

src/core/BufferView.cc

@@ -31,17 +31,6 @@ void BufferView::set_scroll_offset(int scroll_offset)
 
 BufferView::Iterator BufferView::vert_iter()
 {
-    if (m_iterator->valid())
-    {
-        /* TODO: user calls update() before vert_iter(). */
-        update();
-    }
-    else
-    {
-        m_cursor_screen_row = 0;
-        m_cursor_screen_column = 0;
-        m_cursor_virtual_column = 0;
-    }
     return Iterator(*this);
 }
 
@@ -94,6 +83,14 @@ void BufferView::update()
         row_offset += ld.n_rows;
         line_iterator->go_next_line();
     }
+
+    /* Reset some fields if buffer becomes empty. */
+    if (!m_iterator->valid())
+    {
+        m_cursor_screen_row = 0;
+        m_cursor_screen_column = 0;
+        m_cursor_virtual_column = 0;
+    }
 }
 
 int BufferView::calculate_rows_in_line(std::shared_ptr<Buffer::Iterator> start_of_line)

src/core/BufferView.h

@@ -56,6 +56,7 @@ public:
             CharacterWidthDeterminer & character_width_determiner);
     void resize(int width, int height);
     void set_scroll_offset(int scroll_offset);
+    void update();
     Iterator vert_iter();
     BufferLineWalker horiz_iter(std::shared_ptr<Buffer::Iterator> start_of_line)
     {
@@ -88,7 +89,6 @@ protected:
     {
         return std::min(m_scroll_offset, (m_height - 1) / 2);
     }
-    void update();
     int calculate_rows_in_line(std::shared_ptr<Buffer::Iterator> start_of_line);
     int calculate_rows_in_cursor_line(std::shared_ptr<Buffer::Iterator> start_of_line);
     int screen_rows_below_line(std::shared_ptr<Buffer::Iterator> line);

test/src/test_BufferView.cc

@@ -63,6 +63,7 @@ TEST(BufferViewTest, does_not_iterate_for_empty_buffer)
     BufferView bv(b, iterator, Cwd);
     bv.resize(40, 8);
     int iter_count = 0;
+    bv.update();
     for (auto it = bv.vert_iter(); it.is_valid(); it++)
     {
         iter_count++;
@@ -80,6 +81,7 @@ TEST(BufferViewTest, iterates_through_screen_lines_with_no_wrapping)
     BufferView bv(b, iterator, Cwd);
     bv.resize(40, 8);
     int iter_count = 0;
+    bv.update();
     for (auto it = bv.vert_iter(); it.is_valid(); it++)
     {
         EXPECT_EQ(iter_count, LineNumber(it.iterator()));
@@ -99,6 +101,7 @@ TEST(BufferViewTest, iterates_through_screen_lines_with_wrapping)
     bv.resize(3, 10);
     int iter_count = 0;
     int expected_row_offsets[] = {0, 1, 2, 4, 5, 6, 7};
+    bv.update();
     for (auto it = bv.vert_iter(); it.is_valid(); it++)
     {
         EXPECT_EQ(iter_count, LineNumber(it.iterator()));
@@ -122,6 +125,7 @@ TEST(BufferViewTest, fills_view_with_last_lines_of_buffer_when_cursor_warps_to_l
     bv.resize(40, 3);
     int iter_count = 0;
     int expected_row_offsets[] = {0, 1, 2};
+    bv.update();
     for (auto it = bv.vert_iter(); it.is_valid(); it++)
     {
         EXPECT_EQ(10 + iter_count, LineNumber(it.iterator()));