Refactor utf8::iterator to be on the safe side

utf8::iterator now knows the iterator valid range, and pass
it to utf8 functions.

8 files changed, 49 insertions, 58 deletions

diff --git a/src/keys.cc b/src/keys.cc
index 349cbd53..4b9a83ec 100644
--- a/src/keys.cc
+++ b/src/keys.cc
@@ -58,7 +58,7 @@ KeyList parse_keys(StringView str)
 {
     KeyList result;
     using Utf8It = utf8::iterator<const char*>;
-    for (Utf8It it = str.begin(), str_end = str.end(); it < str_end; ++it)
+    for (Utf8It it{str.begin(), str}, str_end{str.end(), str}; it < str_end; ++it)
     {
         if (*it != '<')
         {
diff --git a/src/normal.cc b/src/normal.cc
index 539bf76f..e0648abd 100644
--- a/src/normal.cc
+++ b/src/normal.cc
@@ -637,10 +637,13 @@ void use_selection_as_search_pattern(Context& context, NormalParams)
     Vector<String> patterns;
     auto& sels = context.selections();
     const auto& buffer = context.buffer();
+    using Utf8It = utf8::iterator<BufferIterator, utf8::InvalidPolicy::Pass>;
     for (auto& sel : sels)
     {
-        auto begin = utf8::make_iterator(buffer.iterator_at(sel.min()));
-        auto end   = utf8::make_iterator(buffer.iterator_at(sel.max()))+1;
+        Utf8It begin{buffer.iterator_at(sel.min()), buffer};
+        Utf8It end{buffer.iterator_at(sel.max()), buffer};
+        ++end;
+
         auto content = "\\Q" + buffer.string(begin.base().coord(), end.base().coord()) + "\\E";
         if (smart)
         {
diff --git a/src/selection.cc b/src/selection.cc
index 69cce1b8..b2432d6e 100644
--- a/src/selection.cc
+++ b/src/selection.cc
@@ -394,8 +394,6 @@ void SelectionList::check_invariant() const
         kak_assert(buffer.is_valid(sel.cursor()));
         kak_assert(not buffer.is_end(sel.anchor()));
         kak_assert(not buffer.is_end(sel.cursor()));
-        kak_assert(utf8::is_character_start(buffer.byte_at(sel.anchor())));
-        kak_assert(utf8::is_character_start(buffer.byte_at(sel.cursor())));
     }
 #endif
 }
diff --git a/src/selectors.cc b/src/selectors.cc
index 8965fc51..99f4f95a 100644
--- a/src/selectors.cc
+++ b/src/selectors.cc
@@ -10,7 +10,7 @@ namespace Kakoune
 
 Selection select_line(const Buffer& buffer, const Selection& selection)
 {
-    Utf8Iterator first = buffer.iterator_at(selection.cursor());
+    Utf8Iterator first{buffer.iterator_at(selection.cursor()), buffer};
     if (*first == '\n' and first + 1 != buffer.end())
         ++first;
 
@@ -26,7 +26,7 @@ Selection select_line(const Buffer& buffer, const Selection& selection)
 Selection select_matching(const Buffer& buffer, const Selection& selection)
 {
     Vector<Codepoint> matching_pairs = { '(', ')', '{', '}', '[', ']', '<', '>' };
-    Utf8Iterator it = buffer.iterator_at(selection.cursor());
+    Utf8Iterator it{buffer.iterator_at(selection.cursor()), buffer};
     Vector<Codepoint>::iterator match = matching_pairs.end();
     while (not is_eol(*it))
     {
@@ -82,7 +82,7 @@ static Optional<Selection> find_surrounding(const Buffer& buffer,
     const bool to_end   = flags & ObjectFlags::ToEnd;
     const bool nestable = matching.opening != matching.closing;
     auto pos = buffer.iterator_at(coord);
-    Utf8Iterator first = pos;
+    Utf8Iterator first{pos, buffer};
     if (to_begin)
     {
         int level = nestable ? init_level : 0;
@@ -103,7 +103,7 @@ static Optional<Selection> find_surrounding(const Buffer& buffer,
             return Optional<Selection>{};
     }
 
-    Utf8Iterator last = pos;
+    Utf8Iterator last{pos, buffer};
     if (to_end)
     {
         int level = nestable ? init_level : 0;
@@ -168,7 +168,7 @@ Selection select_surrounding(const Buffer& buffer, const Selection& selection,
 Selection select_to(const Buffer& buffer, const Selection& selection,
                     Codepoint c, int count, bool inclusive)
 {
-    Utf8Iterator begin = buffer.iterator_at(selection.cursor());
+    Utf8Iterator begin{buffer.iterator_at(selection.cursor()), buffer};
     Utf8Iterator end = begin;
     do
     {
@@ -185,7 +185,7 @@ Selection select_to(const Buffer& buffer, const Selection& selection,
 Selection select_to_reverse(const Buffer& buffer, const Selection& selection,
                             Codepoint c, int count, bool inclusive)
 {
-    Utf8Iterator begin = buffer.iterator_at(selection.cursor());
+    Utf8Iterator begin{buffer.iterator_at(selection.cursor()), buffer};
     Utf8Iterator end = begin;
     do
     {
@@ -367,8 +367,8 @@ Selection select_whitespaces(const Buffer& buffer, const Selection& selection, O
             --last;
         }
     }
-    return (flags & ObjectFlags::ToEnd) ? utf8_range(first, last)
-                                        : utf8_range(last, first);
+    return (flags & ObjectFlags::ToEnd) ? Selection{first.coord(), last.coord()}
+                                        : Selection{last.coord(), first.coord()};
 }
 
 Selection select_indent(const Buffer& buffer, const Selection& selection, ObjectFlags flags)
@@ -511,8 +511,8 @@ Selection select_argument(const Buffer& buffer, const Selection& selection,
         --end;
 
     if (flags & ObjectFlags::ToBegin and not (flags & ObjectFlags::ToEnd))
-        return utf8_range(pos, begin);
-    return utf8_range(flags & ObjectFlags::ToBegin ? begin : pos, end);
+        return {pos.coord(), begin.coord()};
+    return {(flags & ObjectFlags::ToBegin ? begin : pos).coord(), end.coord()};
 }
 
 Selection select_lines(const Buffer& buffer, const Selection& selection)
diff --git a/src/selectors.hh b/src/selectors.hh
index 2f638216..7809344f 100644
--- a/src/selectors.hh
+++ b/src/selectors.hh
@@ -48,7 +48,7 @@ inline Selection utf8_range(const Utf8Iterator& first, const Utf8Iterator& last)
 template<WordType word_type>
 Selection select_to_next_word(const Buffer& buffer, const Selection& selection)
 {
-    Utf8Iterator begin = buffer.iterator_at(selection.cursor());
+    Utf8Iterator begin{buffer.iterator_at(selection.cursor()), buffer};
     if (begin+1 == buffer.end())
         return selection;
     if (categorize<word_type>(*begin) != categorize<word_type>(*(begin+1)))
@@ -72,7 +72,7 @@ Selection select_to_next_word(const Buffer& buffer, const Selection& selection)
 template<WordType word_type>
 Selection select_to_next_word_end(const Buffer& buffer, const Selection& selection)
 {
-    Utf8Iterator begin = buffer.iterator_at(selection.cursor());
+    Utf8Iterator begin{buffer.iterator_at(selection.cursor()), buffer};
     if (begin+1 == buffer.end())
         return selection;
     if (categorize<word_type>(*begin) != categorize<word_type>(*(begin+1)))
@@ -95,7 +95,7 @@ Selection select_to_next_word_end(const Buffer& buffer, const Selection& selecti
 template<WordType word_type>
 Selection select_to_previous_word(const Buffer& buffer, const Selection& selection)
 {
-    Utf8Iterator begin = buffer.iterator_at(selection.cursor());
+    Utf8Iterator begin{buffer.iterator_at(selection.cursor()), buffer};
     if (begin == buffer.begin())
         return selection;
     if (categorize<word_type>(*begin) != categorize<word_type>(*(begin-1)))
@@ -160,7 +160,7 @@ Selection select_word(const Buffer& buffer,
                       const Selection& selection,
                       ObjectFlags flags)
 {
-    Utf8Iterator first = buffer.iterator_at(selection.cursor());
+    Utf8Iterator first{buffer.iterator_at(selection.cursor()), buffer};
     Utf8Iterator last = first;
     if (is_word<word_type>(*first))
     {
diff --git a/src/string.cc b/src/string.cc
index b6d0f3de..e0f3525d 100644
--- a/src/string.cc
+++ b/src/string.cc
@@ -225,12 +225,12 @@ Vector<StringView> wrap_lines(StringView text, CharCount max_width)
         throw runtime_error("Invalid max width");
 
     using Utf8It = utf8::iterator<const char*>;
-    Utf8It word_begin{text.begin()};
+    Utf8It word_begin{text.begin(), text};
     Utf8It word_end{word_begin};
-    Utf8It end{text.end()};
+    Utf8It end{text.end(), text};
     CharCount col = 0;
     Vector<StringView> lines;
-    Utf8It line_begin = text.begin();
+    Utf8It line_begin{text.begin(), text};
     Utf8It line_end = line_begin;
     while (word_begin != end)
     {
diff --git a/src/utf8_iterator.hh b/src/utf8_iterator.hh
index 43242a73..b8ba5764 100644
--- a/src/utf8_iterator.hh
+++ b/src/utf8_iterator.hh
@@ -19,12 +19,18 @@ class iterator : public std::iterator<std::forward_iterator_tag,
                                       Codepoint, CharCount>
 {
 public:
-    iterator() = default;
-    iterator(Iterator it) : m_it(std::move(it)) {}
+    iterator(Iterator it, Iterator begin, Iterator end)
+        : m_it{std::move(it)}, m_begin{std::move(begin)}, m_end{std::move(end)}
+    {}
+
+    template<typename Container>
+    iterator(Iterator it, const Container& c)
+        : m_it{std::move(it)}, m_begin{begin(c)}, m_end{end(c)}
+    {}
 
     iterator& operator++()
     {
-        m_it = utf8::next(m_it, Iterator{});
+        m_it = utf8::next(m_it, m_end);
         invalidate_value();
         return *this;
     }
@@ -38,7 +44,7 @@ public:
 
     iterator& operator--()
     {
-        m_it = utf8::previous(m_it, Iterator{});
+        m_it = utf8::previous(m_it, m_begin);
         invalidate_value();
         return *this;
     }
@@ -75,25 +81,20 @@ public:
     bool operator==(const iterator& other) { return m_it == other.m_it; }
     bool operator!=(const iterator& other) { return m_it != other.m_it; }
 
-    bool operator< (const iterator& other) const
-    {
-        return m_it < other.m_it;
-    }
+    bool operator< (const iterator& other) const { return m_it < other.m_it; }
+    bool operator<= (const iterator& other) const { return m_it <= other.m_it; }
 
-    bool operator<= (const iterator& other) const
-    {
-        return m_it <= other.m_it;
-    }
+    bool operator> (const iterator& other) const { return m_it > other.m_it; }
+    bool operator>= (const iterator& other) const { return m_it >= other.m_it; }
 
-    bool operator> (const iterator& other) const
-    {
-        return m_it > other.m_it;
-    }
+    bool operator==(const Iterator& other) { return m_it == other; }
+    bool operator!=(const Iterator& other) { return m_it != other; }
 
-    bool operator>= (const iterator& other) const
-    {
-        return m_it >= other.m_it;
-    }
+    bool operator< (const Iterator& other) const { return m_it < other; }
+    bool operator<= (const Iterator& other) const { return m_it <= other; }
+
+    bool operator> (const Iterator& other) const { return m_it > other; }
+    bool operator>= (const Iterator& other) const { return m_it >= other; }
 
     CharCount operator-(const iterator& other) const
     {
@@ -108,32 +109,21 @@ public:
     const Iterator& base() const { return m_it; }
     Iterator& base() { return m_it; }
 
-protected:
-    void check_invariant() const
-    {
-        // always point to a character first byte;
-        // kak_assert(is_character_start(it));
-    }
-
 private:
     void invalidate_value() { m_value = -1; }
     Codepoint get_value() const
     {
         if (m_value == -1)
-            m_value = utf8::codepoint<InvalidPolicy>(m_it, Iterator{});
+            m_value = utf8::codepoint<InvalidPolicy>(m_it, m_end);
         return m_value;
     }
 
     Iterator m_it;
+    Iterator m_begin;
+    Iterator m_end;
     mutable Codepoint m_value = -1;
 };
 
-template<typename InvalidPolicy = utf8::InvalidPolicy::Pass, typename Iterator>
-iterator<Iterator, InvalidPolicy> make_iterator(Iterator it)
-{
-    return iterator<Iterator, InvalidPolicy>{std::move(it)};
-}
-
 }
 
 }
diff --git a/src/word_db.cc b/src/word_db.cc
index 8ac7c8d3..4ef5a912 100644
--- a/src/word_db.cc
+++ b/src/word_db.cc
@@ -30,10 +30,10 @@ UsedLetters used_letters(StringView str)
 static WordDB::WordList get_words(const SharedString& content)
 {
     WordDB::WordList res;
-    using Iterator = utf8::iterator<const char*, utf8::InvalidPolicy::Pass>;
+    using Utf8It = utf8::iterator<const char*, utf8::InvalidPolicy::Pass>;
     const char* word_start = content.begin();
     bool in_word = false;
-    for (Iterator it{word_start}, end{content.end()}; it != end; ++it)
+    for (Utf8It it{word_start, content}, end{content.end(), content}; it != end; ++it)
     {
         Codepoint c = *it;
         const bool word = is_word(c);