Fix text insertion point not following cursor

Always supply iterator position when inserting code points

src/core/Buffer.cc

@@ -153,13 +153,8 @@ bool Buffer::write_to_file(const char * filename)
     return true;
 }
 
-void Buffer::enter_insert_mode(const Buffer::Iterator & position)
+void Buffer::enter_insert_mode()
 {
-    m_insert_position = position.offset();
-    if (m_insert_position > m_gap_buffer->size())
-    {
-        m_insert_position = 0;
-    }
     m_insert_mode = true;
 }
 
@@ -168,28 +163,28 @@ void Buffer::exit_insert_mode()
     m_insert_mode = false;
 }
 
-void Buffer::insert_code_point(uint32_t code_point, bool adjust_iterators)
+void Buffer::insert_code_point(const Buffer::Iterator & position, uint32_t code_point, bool adjust_iterators)
 {
     if (m_insert_mode)
     {
+        Buffer::Iterator local_position = position;
         if ((code_point != '\n') && (size() == 0u))
         {
-            insert_code_point('\n', false);
+            insert_code_point(position, '\n', false);
         }
         uint8_t encoded[Encoding::MAX_CODE_POINT_SIZE];
         uint8_t bytes = Encoding::encode(code_point, m_encoding, encoded);
-        m_gap_buffer->insert(m_insert_position, encoded, bytes);
+        m_gap_buffer->insert(local_position.offset(), encoded, bytes);
         ssize_t lines = (code_point == '\n') ? 1 : 0;
         if (adjust_iterators)
         {
             for (auto iterator : m_iterators)
             {
-                if (iterator->offset() >= m_insert_position)
+                if (*iterator >= local_position)
                 {
                     iterator->warp(bytes, lines);
                 }
             }
-            m_insert_position += bytes;
         }
     }
 }
@@ -198,20 +193,17 @@ void Buffer::erase_code_point(const Buffer::Iterator & position)
 {
     if (position.valid())
     {
+        Buffer::Iterator local_position = position;
         uint8_t bytes = 0u;
-        uint32_t code_point = Encoding::decode(m_encoding, position.address(), &bytes);
-        m_gap_buffer->erase(position.offset(), bytes);
+        uint32_t code_point = Encoding::decode(m_encoding, local_position.address(), &bytes);
+        m_gap_buffer->erase(local_position.offset(), bytes);
         ssize_t lines = (code_point == '\n') ? -1 : 0;
         for (auto iterator : m_iterators)
         {
-            if (*iterator > position)
+            if (*iterator > local_position)
             {
                 iterator->warp(-(ssize_t)bytes, lines);
             }
         }
-        if (m_insert_position > position.offset())
-        {
-            m_insert_position -= bytes;
-        }
     }
 }

src/core/Buffer.h

@@ -108,10 +108,10 @@ public:
     uint8_t * address(size_t offset) const { return m_gap_buffer->address(offset); }
     Encoding::Type encoding() const { return m_encoding; }
     uint8_t tabstop() const { return m_tabstop; }
-    void enter_insert_mode(const Buffer::Iterator & position);
+    void enter_insert_mode();
     void exit_insert_mode();
     bool insert_mode() const { return m_insert_mode; }
-    void insert_code_point(uint32_t code_point, bool adjust_iterators = true);
+    void insert_code_point(const Buffer::Iterator & position, uint32_t code_point, bool adjust_iterators = true);
     void erase_code_point(const Buffer::Iterator & position);
     std::string filename() const { return m_filename; }
     Iterator begin() const { return Iterator(this); }
@@ -124,7 +124,6 @@ protected:
     Encoding::Type m_encoding;
     uint8_t m_tabstop;
     bool m_insert_mode;
-    size_t m_insert_position;
     std::list<std::shared_ptr<Iterator>> m_iterators;
     std::shared_ptr<Iterator> m_eof_iterator;
     std::string m_filename;