[lmi-commits] [lmi] master a83da7a 1/4: Embark upon inversion of control by making table generator a member

[Greg Chicares]

branch: master
commit a83da7a4a715d07a51c21a5e9905a95b80597d75
Author: Gregory W. Chicares <address@hidden>
Commit: Gregory W. Chicares <address@hidden>

    Embark upon inversion of control by making table generator a member
    
    The goal of this and the next few commits is to invert control in
    rendering paginated tables. Present substeps in render() will become
    overrides; yet the pagination base class naturally knows nothing about
    the necessary local state; and therefore the local state variables of
    render() must become data members of the class. This first commit lays
    that groundwork with respect to the table generator, which is now,
    incidentally, instantiated OAOO in this class.
---
 ledger_pdf_generator_wx.cpp | 62 ++++++++++++++++++++++++++++-----------------
 1 file changed, 39 insertions(+), 23 deletions(-)

diff --git a/ledger_pdf_generator_wx.cpp b/ledger_pdf_generator_wx.cpp
index 4a1caba..420b15c 100644
--- a/ledger_pdf_generator_wx.cpp
+++ b/ledger_pdf_generator_wx.cpp
@@ -40,6 +40,7 @@
 #include "oecumenic_enumerations.hpp"
 #include "pdf_writer_wx.hpp"
 #include "report_table.hpp"             // paginator
+#include "safely_dereference_as.hpp"
 #include "ssize_lmi.hpp"
 #include "wx_table_generator.hpp"
 
@@ -1775,6 +1776,27 @@ class page_with_tabular_report
   public:
     using numbered_page::numbered_page;
 
+    /// Initialize a wx_table_generator.
+    ///
+    /// This cannot be done in the ctor, where the virtual function
+    /// get_table_columns() is still pure; yet it is wasteful to
+    /// recreate inside every member function that uses it; therefore,
+    /// create it OAOO, here--because this is apparently the first
+    /// function called after the derived-class ctors have run.
+    ///
+    /// Create the wx_table_generator before calling the base-class
+    /// implementation, which calls get_extra_pages_needed(), which
+    /// uses the object initialized here.
+
+    void pre_render
+        (Ledger        const& ledger
+        ,pdf_writer_wx      & writer
+        ) override
+    {
+        table_gen_.reset(new wx_table_generator 
{create_table_generator(ledger, writer)});
+        numbered_page::pre_render(ledger, writer);
+    }
+
     void render
         (Ledger        const& ledger
         ,pdf_writer_wx      & writer
@@ -1782,10 +1804,8 @@ class page_with_tabular_report
     {
         numbered_page::render(ledger, writer);
 
-        wx_table_generator table_gen{create_table_generator(ledger, writer)};
-
         // Just some cached values used inside the loop below.
-        auto const row_height = table_gen.row_height();
+        auto const row_height = table_gen().row_height();
         auto const page_bottom = get_footer_top();
         auto const rows_per_group = wx_table_generator::rows_per_group;
 
@@ -1793,16 +1813,12 @@ class page_with_tabular_report
         int const year_max = ledger.GetMaxLength();
         for(int year = 0; year < year_max; )
             {
-            int pos_y = render_or_measure_fixed_page_part
-                (table_gen
-                ,writer
-                ,oe_render
-                );
+            int pos_y = render_or_measure_fixed_page_part(writer, oe_render);
 
             for(;;)
                 {
                 auto const v = visible_values(ledger, interpolate_html_, year);
-                table_gen.output_row(pos_y, v);
+                table_gen().output_row(pos_y, v);
 
                 ++year;
                 if(year == year_max)
@@ -1856,12 +1872,16 @@ class page_with_tabular_report
     }
 
   private:
+    wx_table_generator& table_gen() const
+    {
+        return safely_dereference_as<wx_table_generator>(table_gen_.get());
+    }
+
     // Render (only if output_mode is oe_render) the fixed page part and
     // (in any case) return the vertical coordinate of its bottom, where the
     // tabular report starts.
     int render_or_measure_fixed_page_part
-        (wx_table_generator           & table_gen
-        ,pdf_writer_wx                & writer
+        (pdf_writer_wx                & writer
         ,oenum_render_or_only_measure   output_mode
         ) const
     {
@@ -1878,16 +1898,16 @@ class page_with_tabular_report
             );
 
         render_or_measure_extra_headers
-            (table_gen
+            (table_gen()
             ,pos_y
             ,output_mode
             );
 
-        table_gen.output_headers(pos_y, output_mode);
+        table_gen().output_headers(pos_y, output_mode);
 
         auto const ncols = get_table_columns().size();
-        table_gen.output_horz_separator(0, ncols, pos_y, output_mode);
-        pos_y += table_gen.separator_line_height();
+        table_gen().output_horz_separator(0, ncols, pos_y, output_mode);
+        pos_y += table_gen().separator_line_height();
 
         return pos_y;
     }
@@ -1899,15 +1919,9 @@ class page_with_tabular_report
         ,pdf_writer_wx      & writer
         ) override
     {
-        wx_table_generator table_gen{create_table_generator(ledger, writer)};
+        int const pos_y = render_or_measure_fixed_page_part(writer, 
oe_only_measure);
 
-        int const pos_y = render_or_measure_fixed_page_part
-            (table_gen
-            ,writer
-            ,oe_only_measure
-            );
-
-        int const max_lines_per_page = (get_footer_top() - pos_y) / 
table_gen.row_height();
+        int const max_lines_per_page = (get_footer_top() - pos_y) / 
table_gen().row_height();
 
         int const rows_per_group = wx_table_generator::rows_per_group;
 
@@ -1923,6 +1937,8 @@ class page_with_tabular_report
         // "- 1": return the number of *extra* pages.
         return z.page_count() - 1;
     }
+
+    std::unique_ptr<wx_table_generator> table_gen_;
 };
 
 class ill_reg_tabular_detail_page : public page_with_tabular_report