Avoid temporary strings on buffer load/reload

Pass directly a Vector<ref_ptr<StringStorage>> to the buffer

src/buffer.cc

@@ -15,7 +15,7 @@
 namespace Kakoune
 {
 
-Buffer::Buffer(String name, Flags flags, Vector<String> lines,
+Buffer::Buffer(String name, Flags flags, BufferLines lines,
                time_t fs_timestamp)
     : Scope(GlobalScope::instance()),
       m_name(flags & Flags::File ? real_path(parse_filename(name)) : std::move(name)),
@@ -28,14 +28,13 @@ Buffer::Buffer(String name, Flags flags, Vector<String> lines,
     options().register_watcher(*this);
 
     if (lines.empty())
-        lines.emplace_back("\n");
+        lines.emplace_back(StringStorage::create("\n"));
 
-    m_lines.reserve(lines.size());
     for (auto& line : lines)
     {
-        kak_assert(not line.empty() and line.back() == '\n');
+        kak_assert(not line->length == 0 and line->data[line->length-1] == '\n');
-        m_lines.emplace_back(StringStorage::create(line));
     }
+    static_cast<BufferLines&>(m_lines) = std::move(lines);
 
     m_changes.push_back({ Change::Insert, {0,0}, line_count(), true });
 
@@ -157,7 +156,7 @@ struct Buffer::Modification
     }
 };
 
-void Buffer::reload(Vector<String> lines, time_t fs_timestamp)
+void Buffer::reload(BufferLines lines, time_t fs_timestamp)
 {
     m_changes.push_back({ Change::Erase, {0,0}, back_coord(), true });
 
@@ -169,20 +168,18 @@ void Buffer::reload(Vector<String> lines, time_t fs_timestamp)
                 Modification::Erase, line, m_lines[line]);
     }
 
-    m_lines.clear();
-
     if (lines.empty())
-        lines.emplace_back("\n");
+        lines.emplace_back(StringStorage::create("\n"));
 
-    m_lines.reserve(lines.size());
     for (auto& line : lines)
     {
-        kak_assert(not line.empty() and line.back() == '\n');
+        kak_assert(not line->length == 0 and line->data[line->length-1] == '\n');
-        m_lines.emplace_back(StringStorage::create(line));
         if (not (m_flags & Flags::NoUndo))
             m_current_undo_group.emplace_back(
                 Modification::Insert, line_count()-1, m_lines.back());
     }
+    static_cast<BufferLines&>(m_lines) = std::move(lines);
+
     commit_undo_group();
 
     m_last_save_undo_index = m_history_cursor - m_history.begin();

src/buffer.hh

@@ -59,6 +59,8 @@ private:
     ByteCoord m_coord;
 };
 
+using BufferLines = Vector<ref_ptr<StringStorage>, MemoryDomain::BufferContent>;
+
 // A Buffer is a in-memory representation of a file
 //
 // The Buffer class permits to read and mutate this file
@@ -76,7 +78,7 @@ public:
         NoUndo = 8,
     };
 
-    Buffer(String name, Flags flags, Vector<String> lines = { "\n" },
+    Buffer(String name, Flags flags, BufferLines lines = {},
            time_t fs_timestamp = InvalidTime);
     Buffer(const Buffer&) = delete;
     Buffer& operator= (const Buffer&) = delete;
@@ -150,7 +152,7 @@ public:
 
     void run_hook_in_own_context(const String& hook_name, StringView param);
 
-    void reload(Vector<String> lines, time_t fs_timestamp = InvalidTime);
+    void reload(BufferLines lines, time_t fs_timestamp = InvalidTime);
 
     void check_invariant() const;
 
@@ -169,16 +171,15 @@ private:
 
     void on_option_changed(const Option& option) override;
 
-    using LineListBase = Vector<ref_ptr<StringStorage>, MemoryDomain::BufferContent>;
+    struct LineList : BufferLines
-    struct LineList : LineListBase
     {
         [[gnu::always_inline]]
         ref_ptr<StringStorage>& get_storage(LineCount line)
-        { return LineListBase::operator[]((int)line); }
+        { return BufferLines::operator[]((int)line); }
 
         [[gnu::always_inline]]
         const ref_ptr<StringStorage>& get_storage(LineCount line) const
-        { return LineListBase::operator[]((int)line); }
+        { return BufferLines::operator[]((int)line); }
 
         [[gnu::always_inline]]
         SharedString get_shared(LineCount line) const
@@ -188,8 +189,8 @@ private:
         StringView operator[](LineCount line) const
         { return get_storage(line)->strview(); }
 
-        StringView front() const { return LineListBase::front()->strview(); }
+        StringView front() const { return BufferLines::front()->strview(); }
-        StringView back() const { return LineListBase::back()->strview(); }
+        StringView back() const { return BufferLines::back()->strview(); }
     };
     LineList m_lines;
 

src/buffer_utils.cc

@@ -39,24 +39,14 @@ Buffer* create_buffer_from_data(StringView data, StringView name,
         pos = data.begin() + 3;
     }
 
-    Vector<String> lines;
+    BufferLines lines;
     while (pos < data.end())
     {
         const char* line_end = pos;
         while (line_end < data.end() and *line_end != '\r' and *line_end != '\n')
              ++line_end;
 
-        // this should happen only when opening a file which has no
+        lines.emplace_back(StringStorage::create({pos, line_end}, '\n'));
-        // end of line as last character.
-        if (line_end == data.end())
-        {
-            lines.emplace_back(pos, line_end);
-            lines.back() += '\n';
-            break;
-        }
-
-        lines.emplace_back(pos, line_end + 1);
-        lines.back().back() = '\n';
 
         if (line_end+1 != data.end() and *line_end == '\r' and *(line_end+1) == '\n')
         {
@@ -88,7 +78,7 @@ Buffer* create_fifo_buffer(String name, int fd, bool scroll)
     if (buffer)
     {
         buffer->flags() |= Buffer::Flags::NoUndo;
-        buffer->reload(Vector<String>({"\n"_str}), 0);
+        buffer->reload({"\n"_ss}, 0);
     }
     else
         buffer = new Buffer(std::move(name), Buffer::Flags::Fifo | Buffer::Flags::NoUndo);

src/shared_string.hh

@@ -17,14 +17,16 @@ struct StringStorage : UseMemoryDomain<MemoryDomain::SharedString>
 
     StringView strview() const { return {data, length}; }
 
-    static StringStorage* create(StringView str)
+    static StringStorage* create(StringView str, char back = 0)
     {
-        const int len = (int)str.length();
+        const int len = (int)str.length() + (back != 0 ? 1 : 0);
         void* ptr = StringStorage::operator new(sizeof(StringStorage) + len);
         StringStorage* res = reinterpret_cast<StringStorage*>(ptr);
-        memcpy(res->data, str.data(), len);
+        memcpy(res->data, str.data(), (int)str.length());
         res->refcount = 0;
         res->length = len;
+        if (back != 0)
+            res->data[len-1] = back;
         res->data[len] = 0;
         return res;
     }
@@ -38,6 +40,11 @@ struct StringStorage : UseMemoryDomain<MemoryDomain::SharedString>
     friend void dec_ref_count(StringStorage* s) { if (--s->refcount == 0) StringStorage::destroy(s); }
 };
 
+inline ref_ptr<StringStorage> operator""_ss(const char* ptr, size_t len)
+{
+    return StringStorage::create({ptr, (int)len});
+}
+
 class SharedString : public StringView
 {
 public:

src/unit_tests.cc

@@ -10,7 +10,7 @@ void test_buffer()
 {
     Buffer empty_buffer("empty", Buffer::Flags::None, {});
 
-    Buffer buffer("test", Buffer::Flags::None, { "allo ?\n", "mais que fais la police\n",  " hein ?\n", " youpi\n" });
+    Buffer buffer("test", Buffer::Flags::None, { "allo ?\n"_ss, "mais que fais la police\n"_ss,  " hein ?\n"_ss, " youpi\n"_ss });
     kak_assert(buffer.line_count() == 4);
 
     BufferIterator pos = buffer.begin();
@@ -53,7 +53,7 @@ void test_buffer()
 
 void test_undo_group_optimizer()
 {
-    Vector<String> lines = { "allo ?\n", "mais que fais la police\n",  " hein ?\n", " youpi\n" };
+    BufferLines lines = { "allo ?\n"_ss, "mais que fais la police\n"_ss,  " hein ?\n"_ss, " youpi\n"_ss };
     Buffer buffer("test", Buffer::Flags::None, lines);
     auto pos = buffer.insert(buffer.end(), "kanaky\n");
     buffer.erase(pos, buffer.end());
@@ -68,17 +68,17 @@ void test_undo_group_optimizer()
 
     kak_assert((int)buffer.line_count() == lines.size());
     for (size_t i = 0; i < lines.size(); ++i)
-        kak_assert(lines[i] == buffer[LineCount((int)i)]);
+        kak_assert(SharedString{lines[i]} == buffer[LineCount((int)i)]);
 }
 
 void test_word_db()
 {
     Buffer buffer("test", Buffer::Flags::None,
-                  { "tchou mutch\n",
+                  { "tchou mutch\n"_ss,
-                    "tchou kanaky tchou\n",
+                    "tchou kanaky tchou\n"_ss,
-                    "\n",
+                    "\n"_ss,
-                    "tchaa tchaa\n",
+                    "tchaa tchaa\n"_ss,
-                    "allo\n"});
+                    "allo\n"_ss});
     WordDB word_db(buffer);
     auto res = word_db.find_matching("", prefix_match);
     std::sort(res.begin(), res.end());