Templatize StringData::create

This improves performance by letting the compiler optimize most use
cases where string count and length are known are compile time.

src/buffer.cc

@@ -430,14 +430,14 @@ BufferRange Buffer::do_insert(BufferCoord pos, StringView content)
         if (content[i] == '\n')
         {
             StringView line = content.substr(start, i + 1 - start);
-            new_lines.push_back(start == 0 ? StringData::create({prefix, line}) : StringData::create({line}));
+            new_lines.push_back(start == 0 ? StringData::create(prefix, line) : StringData::create(line));
             start = i + 1;
         }
     }
     if (start == 0)
-        new_lines.push_back(StringData::create({prefix, content, suffix}));
+        new_lines.push_back(StringData::create(prefix, content, suffix));
     else if (start != content.length() or not suffix.empty())
-        new_lines.push_back(StringData::create({content.substr(start), suffix}));
+        new_lines.push_back(StringData::create(content.substr(start), suffix));
 
     auto line_it = m_lines.begin() + (int)pos.line;
     auto new_lines_it = new_lines.begin();
@@ -466,7 +466,7 @@ BufferCoord Buffer::do_erase(BufferCoord begin, BufferCoord end)
     StringView prefix = m_lines[begin.line].substr(0, begin.column);
     StringView suffix = end.line == line_count() ? StringView{} : m_lines[end.line].substr(end.column);
 
-    auto new_line = (not prefix.empty() or not suffix.empty()) ? StringData::create({prefix, suffix}) : StringDataPtr{};
+    auto new_line = (not prefix.empty() or not suffix.empty()) ? StringData::create(prefix, suffix) : StringDataPtr{};
     m_lines.erase(m_lines.begin() + (int)begin.line, m_lines.begin() + (int)end.line);
 
     m_changes.push_back({ Change::Erase, begin, end });
@@ -691,7 +691,7 @@ String Buffer::debug_description() const
 
 UnitTest test_buffer{[]()
 {
-    auto make_lines = [](auto&&... lines) { return BufferLines{StringData::create({lines})...}; };
+    auto make_lines = [](auto&&... lines) { return BufferLines{StringData::create(lines)...}; };
 
     Buffer empty_buffer("empty", Buffer::Flags::None, make_lines("\n"));
 
@@ -738,7 +738,7 @@ UnitTest test_buffer{[]()
 
 UnitTest test_undo{[]()
 {
-    auto make_lines = [](auto&&... lines) { return BufferLines{StringData::create({lines})...}; };
+    auto make_lines = [](auto&&... lines) { return BufferLines{StringData::create(lines)...}; };
 
     Buffer buffer("test", Buffer::Flags::None, make_lines("allo ?\n", "mais que fais la police\n", " hein ?\n", " youpi\n"));
     auto pos = buffer.end_coord();

src/buffer_manager.cc

@@ -83,8 +83,8 @@ Buffer& BufferManager::get_first_buffer()
 {
     if (all_of(m_buffers, [](auto& b) { return (b->flags() & Buffer::Flags::Debug); }))
         create_buffer("*scratch*", Buffer::Flags::None,
-                      {StringData::create({"*** this is a *scratch* buffer which won't be automatically saved ***\n"}),
+                      {StringData::create("*** this is a *scratch* buffer which won't be automatically saved ***\n"),
-                       StringData::create({"*** use it for notes or open a file buffer with the :edit command ***\n"})},
+                       StringData::create("*** use it for notes or open a file buffer with the :edit command ***\n")},
                       ByteOrderMark::None, EolFormat::Lf, {InvalidTime, {}, {}});
 
     return *m_buffers.back();

src/buffer_utils.cc

@@ -97,12 +97,12 @@ static BufferLines parse_lines(const char* pos, const char* end, EolFormat eolfo
         if ((eol - pos) >= std::numeric_limits<int>::max())
             throw runtime_error("line is too long");
 
-        lines.emplace_back(StringData::create({{pos, eol - (eolformat == EolFormat::Crlf and eol != end ? 1 : 0)}, "\n"}));
+        lines.emplace_back(StringData::create(StringView{pos, eol - (eolformat == EolFormat::Crlf and eol != end ? 1 : 0)}, "\n"));
         pos = eol + 1;
     }
 
     if (lines.empty())
-        lines.emplace_back(StringData::create({"\n"}));
+        lines.emplace_back(StringData::create("\n"));
 
     return lines;
 }
@@ -179,12 +179,12 @@ Buffer* create_fifo_buffer(String name, int fd, Buffer::Flags flags, bool scroll
     {
         buffer->flags() |= Buffer::Flags::NoUndo | flags;
         buffer->values().clear();
-        buffer->reload({StringData::create({"\n"})}, ByteOrderMark::None, EolFormat::Lf, {InvalidTime, {}, {}});
+        buffer->reload({StringData::create("\n")}, ByteOrderMark::None, EolFormat::Lf, {InvalidTime, {}, {}});
     }
     else
         buffer = buffer_manager.create_buffer(
             std::move(name), flags | Buffer::Flags::Fifo | Buffer::Flags::NoUndo,
-            {StringData::create({"\n"})}, ByteOrderMark::None, EolFormat::Lf, {InvalidTime, {}, {}});
+            {StringData::create("\n")}, ByteOrderMark::None, EolFormat::Lf, {InvalidTime, {}, {}});
 
     struct FifoWatcher : FDWatcher
     {

src/line_modification.cc

@@ -196,7 +196,7 @@ void LineRangeSet::remove_range(LineRange range)
 
 UnitTest test_line_modifications{[]()
 {
-    auto make_lines = [](auto&&... lines) { return BufferLines{StringData::create({lines})...}; };
+    auto make_lines = [](auto&&... lines) { return BufferLines{StringData::create(lines)...}; };
 
     {
         Buffer buffer("test", Buffer::Flags::None, make_lines("line 1\n", "line 2\n"));

src/shared_string.cc

@@ -1,30 +1,9 @@
 #include "shared_string.hh"
 #include "buffer_utils.hh"
 
-#include <cstring>
-
 namespace Kakoune
 {
 
-StringDataPtr StringData::create(ArrayView<const StringView> strs)
-{
-    const int len = accumulate(strs, 0, [](int l, StringView s) {
-                        return l + (int)s.length();
-                    });
-    void* ptr = StringData::operator new(sizeof(StringData) + len + 1);
-    auto* res = new (ptr) StringData(len);
-    auto* data = reinterpret_cast<char*>(res + 1);
-    for (auto& str : strs)
-    {
-        if (str.length() == 0) // memccpy(..., nullptr, 0) is UB
-            continue;
-        memcpy(data, str.begin(), (size_t)str.length());
-        data += (int)str.length();
-    }
-    *data = 0;
-    return RefPtr<StringData, PtrPolicy>{res};
-}
-
 StringDataPtr StringData::Registry::intern(StringView str, size_t hash)
 {
     kak_assert(hash_value(str) == hash);

src/shared_string.hh

@@ -7,6 +7,7 @@
 #include "hash_map.hh"
 
 #include <numeric>
+#include <cstring>
 
 namespace Kakoune
 {
@@ -32,13 +33,12 @@ private:
         static void inc_ref(StringData* r, void*) noexcept { ++r->refcount; }
         static void dec_ref(StringData* r, void*) noexcept
         {
-            if ((--r->refcount & refcount_mask) == 0)
+            if ((--r->refcount & refcount_mask) > 0)
-            {
+                return;
             if (r->refcount & interned_flag)
                 Registry::instance().remove(r->strview());
             StringData::operator delete(r, sizeof(StringData) + r->length + 1);
         }
-        }
         static void ptr_moved(StringData*, void*, void*) noexcept {}
     };
 
@@ -57,7 +57,23 @@ public:
         HashMap<StringView, StringData*, MemoryDomain::SharedString> m_strings;
     };
 
-    static Ptr create(ArrayView<const StringView> strs);
+    static Ptr create(ConvertibleTo<StringView> auto&&... strs)
+    {
+        const int len = ((int)StringView{strs}.length() + ...);
+        void* ptr = StringData::operator new(sizeof(StringData) + len + 1);
+        auto* res = new (ptr) StringData(len);
+        auto* data = reinterpret_cast<char*>(res + 1);
+        auto append = [&](StringView str) {
+            if (str.empty()) // memccpy(..., nullptr, 0) is UB
+                return;
+            memcpy(data, str.begin(), (size_t)str.length());
+            data += (int)str.length();
+        };
+        (append(strs), ...);
+        *data = 0;
+        return RefPtr<StringData, PtrPolicy>{res};
+    }
+
 };
 
 using StringDataPtr = StringData::Ptr;

src/word_db.cc

@@ -223,7 +223,7 @@ UnitTest test_word_db{[]()
                        });
     };
 
-    auto make_lines = [](auto&&... lines) { return BufferLines{StringData::create({lines})...}; };
+    auto make_lines = [](auto&&... lines) { return BufferLines{StringData::create(lines)...}; };
 
     Buffer buffer("test", Buffer::Flags::None,
                   make_lines("tchou mutch\n", "tchou kanaky tchou\n", "\n", "tchaa tchaa\n", "allo\n"));