zero-copy text_item insertion

include/mapnik/text/harfbuzz_shaper.hpp

@@ -76,12 +76,12 @@ static void shape_text(text_line & line,
     hb_buffer_pre_allocate(buffer.get(), length);
     mapnik::value_unicode_string const& text = itemizer.text();
 
-    font_feature_settings_ptr features = list.front().format->font_feature_settings;
+    font_feature_settings_ptr features = list.front().format_->font_feature_settings;
 
     for (auto const& text_item : list)
     {
-        face_set_ptr face_set = font_manager.get_face_set(text_item.format->face_name, text_item.format->fontset);
-        double size = text_item.format->text_size * scale_factor;
+        face_set_ptr face_set = font_manager.get_face_set(text_item.format_->face_name, text_item.format_->fontset);
+        double size = text_item.format_->text_size * scale_factor;
         face_set->set_unscaled_character_sizes();
         std::size_t num_faces = face_set->size();
         std::size_t pos = 0;
@@ -90,7 +90,7 @@ static void shape_text(text_line & line,
             ++pos;
             hb_buffer_clear_contents(buffer.get());
             hb_buffer_add_utf16(buffer.get(), uchar_to_utf16(text.getBuffer()), text.length(), text_item.start, text_item.end - text_item.start);
-            hb_buffer_set_direction(buffer.get(), (text_item.rtl == UBIDI_RTL)?HB_DIRECTION_RTL:HB_DIRECTION_LTR);
+            hb_buffer_set_direction(buffer.get(), (text_item.dir == UBIDI_RTL)?HB_DIRECTION_RTL:HB_DIRECTION_LTR);
             hb_buffer_set_script(buffer.get(), _icu_script_to_script(text_item.script));
             hb_font_t *font(hb_ft_font_create(face->get_face(), nullptr));
             hb_shape(font, buffer.get(), features->get_features(), features->count());
@@ -127,7 +127,7 @@ static void shape_text(text_line & line,
                 if (face->glyph_dimensions(g))
                 {
                     g.face = face;
-                    g.format = text_item.format;
+                    g.format = text_item.format_;
                     g.scale_multiplier = size / face->get_face()->units_per_EM;
                     //Overwrite default advance with better value provided by HarfBuzz
                     g.unscaled_advance = pos.x_advance;

include/mapnik/text/itemizer.hpp

@@ -26,6 +26,7 @@
 //mapnik
 #include <mapnik/text/evaluated_format_properties_ptr.hpp>
 #include <mapnik/value_types.hpp>
+#include <mapnik/noncopyable.hpp>
 
 // stl
 #include <string>
@@ -36,18 +37,28 @@
 #include <unicode/unistr.h>
 #include <unicode/uscript.h>
 #include <unicode/ubidi.h>
+
 namespace mapnik
 {
 
-struct text_item
+struct text_item : noncopyable
 {
-    // First char (UTF16 offset)
-    unsigned start = 0u;
-    // Char _after_ the last char (UTF16 offset)
-    unsigned end = 0u;
-    UScriptCode script = USCRIPT_INVALID_CODE;
-    UBiDiDirection rtl = UBIDI_LTR;
-    evaluated_format_properties_ptr format;
+    text_item(unsigned s,
+              unsigned e,
+              UScriptCode sc,
+              UBiDiDirection d,
+              evaluated_format_properties_ptr f)
+      : start(s),
+        end(e),
+        script(sc),
+        dir(d),
+        format_(f) {}
+    text_item( text_item && ) = default;
+    unsigned start; // First char (UTF16 offset)
+    unsigned end; // Char _after_ the last char (UTF16 offset)
+    UScriptCode script;
+    UBiDiDirection dir;
+    evaluated_format_properties_ptr format_;
 };
 
 // This class splits text into parts which all have the same

src/text/itemizer.cpp

@@ -177,21 +177,15 @@ void text_itemizer::create_item_list()
         {
             assert(script_itr != script_runs_.end());
             assert(format_itr != format_runs_.end());
-            text_item item;
-            item.start = position;
+            unsigned start = position;
             position = std::min(script_itr->end, std::min(format_itr->end, end));
-            item.end = position;
-            item.format = format_itr->data;
-            item.script = script_itr->data;
-            item.rtl = dir_run.data;
-
             if (dir_run.data == UBIDI_LTR)
             {
-                output_.push_back(item);
+                output_.emplace_back(start,position,script_itr->data,dir_run.data,format_itr->data);
             }
             else
             {
-                rtl_insertion_point = output_.insert(rtl_insertion_point, item);
+                rtl_insertion_point = output_.emplace(rtl_insertion_point,start,position,script_itr->data,dir_run.data,format_itr->data);
             }
             if (script_itr->end == position) ++script_itr;
             if (format_itr->end == position) ++format_itr;