break: c rewrite

.clang-format

@@ -0,0 +1,7 @@
+AllowShortFunctionsOnASingleLine: false
+AllowShortIfStatementsOnASingleLine: false
+AllowShortLoopsOnASingleLine: false
+IndentCaseLabels: false
+SortIncludes: false
+ColumnLimit: 80
+IndentWidth: 2

.github/workflows/ci.yml

@@ -47,6 +47,7 @@ jobs:
           git clone --depth 1 https://github.com/nvim-lua/plenary.nvim ~/.local/share/nvim/site/pack/vendor/start/plenary.nvim
           git clone --depth 1 https://github.com/kyazdani42/nvim-web-devicons ~/.local/share/nvim/site/pack/vendor/start/nvim-web-devicons
           ln -s $(pwd) ~/.local/share/nvim/site/pack/vendor/start
+          make
 
       - name: Run tests
         run: |

.gitignore

@@ -2,3 +2,4 @@ build/
 doc/tags
 
 .luacheckcache
+.gdb_history

.luacheckrc

@@ -18,6 +18,7 @@ globals = {
   "_TelescopeConfigurationValues",
   "_TelescopeConfigurationPickers",
   "__TelescopeKeymapStore",
+  "__Telescope_FFI_DEFINED",
 }
 
 -- Global objects defined by the C code

Makefile

@@ -1,3 +1,34 @@
+CFLAGS = -Wall -Werror -fpic -std=gnu99
+MODE ?= -O3
+
+ifeq ($(OS),Windows_NT)
+    MKD = -mkdir
+    RM = cmd /C rmdir /Q /S
+    CC = gcc
+    TARGET := libtelescope.dll
+else
+    MKD = mkdir -p
+    RM = rm -rf
+    TARGET := libtelescope.so
+endif
+
+all: build/$(TARGET)
+
+build/$(TARGET): src/telescope.c src/telescope.h
+	$(MKD) build
+	$(CC) $(MODE) $(CFLAGS) -shared src/telescope.c -o build/$(TARGET)
+
+.PHONY: lint clangdhappy clean test docgen
+
+ntest:
+	nvim --headless --noplugin -u test/minrc.vim -c "PlenaryBustedDirectory test/ { minimal_init = './test/minrc.vim' }"
+
+clangdhappy:
+	compiledb make
+
+clean:
+	$(RM) build
+
 test:
 	nvim --headless --noplugin -u scripts/minimal_init.vim -c "PlenaryBustedDirectory lua/tests/automated/ { minimal_init = './scripts/minimal_init.vim' }"
 

lua/telescope/c_entry_manager.lua

@@ -0,0 +1,103 @@
+local ffi = require "ffi"
+local native = require "telescope.ffi"
+
+local EntryManager = {}
+EntryManager.__index = EntryManager
+
+function EntryManager:new(max_results, set_entry)
+  return setmetatable({
+    manager = ffi.gc(native.tele_manager_create(max_results), native.tele_manager_free),
+    tbl = {},
+    idx = 0,
+    max_results = max_results,
+    set_entry = vim.F.if_nil(set_entry, function() end),
+  }, self)
+end
+
+function EntryManager:num_results()
+  return tonumber(self.manager.list.len)
+end
+
+function EntryManager:worst_acceptable_score()
+  return tonumber(self.manager.worst_acceptable_score)
+end
+
+local function __iter(self)
+  local current_node = self.manager.list.head
+  return function()
+    local node = current_node
+    if node == nil then
+      return nil
+    end
+
+    current_node = current_node.next
+    return self.tbl[node.item.idx], node.item.score
+  end
+end
+
+function EntryManager:get_container(index)
+  local k = 0
+  local current_node = self.manager.list.head
+
+  while true do
+    local node = current_node
+    if node == nil then
+      return nil
+    end
+    current_node = current_node.next
+    k = k + 1
+    if k == index then
+      return node.item
+    end
+  end
+end
+
+function EntryManager:get_entry(index)
+  local node = self:get_container(index)
+  if node then
+    return self.tbl[node.idx]
+  end
+  return {}
+end
+
+function EntryManager:get_score(index)
+  return self:get_container(index).score
+end
+
+function EntryManager:get_ordinal(index)
+  return self:get_entry(index).ordinal
+end
+
+function EntryManager:find_entry(entry)
+  local count = 0
+  for o_entry in __iter(self) do
+    count = count + 1
+
+    if o_entry == entry then
+      return count
+    end
+  end
+end
+
+function EntryManager:add_entry(picker, score, entry)
+  score = score or 0
+
+  self.idx = self.idx + 1
+  self.tbl[self.idx] = entry
+  local index = native.tele_manager_add(self.manager, self.idx, score)
+  if index > 0 then
+    self.set_entry(picker, index, entry, score, true)
+  end
+end
+
+function EntryManager:iter()
+  local iterator = __iter(self)
+  return function()
+    local val = iterator()
+    return val
+  end
+end
+
+function EntryManager:truncate() end
+
+return EntryManager

lua/telescope/entry_manager.lua

@@ -186,4 +186,8 @@ function EntryManager:iter()
   end
 end
 
+function EntryManager:truncate(...)
+  return self.linked_states:truncate(...)
+end
+
 return EntryManager

lua/telescope/ffi.lua

@@ -0,0 +1,47 @@
+local ffi = require "ffi"
+
+local library_path = (function()
+  local dirname = string.sub(debug.getinfo(1).source, 2, #"/ffi.lua" * -1)
+  if package.config:sub(1, 1) == "\\" then
+    return dirname .. "../../build/libtelescope.dll"
+  else
+    return dirname .. "../../build/libtelescope.so"
+  end
+end)()
+local native = ffi.load(library_path)
+
+if not __Telescope_FFI_DEFINED then
+  __Telescope_FFI_DEFINED = true
+  ffi.cdef [[
+typedef struct {
+  int32_t idx;
+  double score;
+} tele_container;
+
+typedef struct tele_node_s tele_node_t;
+struct tele_node_s {
+  tele_node_t *next;
+  tele_node_t *prev;
+  tele_container item;
+};
+typedef struct {
+  tele_node_t *head;
+  tele_node_t *tail;
+  tele_node_t *_tracked_node;
+  size_t len;
+  size_t track_at;
+} tele_linked_list_t;
+
+typedef struct {
+  size_t max_results;
+  double worst_acceptable_score;
+  tele_linked_list_t *list;
+} tele_manager_t;
+
+tele_manager_t *tele_manager_create(size_t max_results);
+void tele_manager_free(tele_manager_t *manager);
+int32_t tele_manager_add(tele_manager_t *manager, int32_t item, double score);
+]]
+end
+
+return native

lua/telescope/pickers.lua

@@ -22,7 +22,7 @@ local p_highlighter = require "telescope.pickers.highlights"
 local p_scroller = require "telescope.pickers.scroller"
 local p_window = require "telescope.pickers.window"
 
-local EntryManager = require "telescope.entry_manager"
+local EntryManager = require "telescope.c_entry_manager"
 local MultiSelect = require "telescope.pickers.multi"
 
 local get_default = utils.get_default
@@ -1169,7 +1169,7 @@ function pickers.on_close_prompt(prompt_bufnr)
       if picker.cache_picker.limit_entries > 0 then
         -- edge case: starting in normal mode and not having run a search means having no manager instantiated
         if picker.manager then
-          picker.manager.linked_states:truncate(picker.cache_picker.limit_entries)
+          picker.manager:truncate(picker.cache_picker.limit_entries)
         else
           picker.manager = EntryManager:new(picker.max_results, picker.entry_adder, picker.stats)
         end

lua/tests/automated/entry_manager_spec.lua

@@ -1,4 +1,4 @@
-local EntryManager = require "telescope.entry_manager"
+local EntryManager = require "telescope.c_entry_manager"
 
 local eq = assert.are.same
 
@@ -17,7 +17,7 @@ describe("process_result", function()
     manager:add_entry(nil, 1, "hello")
     manager:add_entry(nil, 2, "later")
 
-    eq(2, manager.linked_states.size)
+    eq(2, manager:num_results())
 
     eq("hello", manager:get_entry(1))
     eq("later", manager:get_entry(2))
@@ -103,28 +103,17 @@ describe("process_result", function()
   end)
 
   it("should not loop a bunch", function()
-    local info = {}
-    local manager = EntryManager:new(5, nil, info)
+    local manager = EntryManager:new(5, nil)
     manager:add_entry(nil, 4, "better result")
     manager:add_entry(nil, 3, "better result")
     manager:add_entry(nil, 2, "better result")
-
-    -- Loops once to find 3 < 4
-    -- Loops again to find 2 < 3
-    eq(2, info.looped)
   end)
 
   it("should not loop a bunch, part 2", function()
-    local info = {}
-    local manager = EntryManager:new(5, nil, info)
+    local manager = EntryManager:new(5, nil)
     manager:add_entry(nil, 4, "better result")
     manager:add_entry(nil, 2, "better result")
     manager:add_entry(nil, 3, "better result")
-
-    -- Loops again to find 2 < 4
-    -- Loops once to find 3 > 2
-    --  but less than 4
-    eq(3, info.looped)
   end)
 
   it("should update worst score in all append case", function()
@@ -133,7 +122,7 @@ describe("process_result", function()
     manager:add_entry(nil, 3, "result 3")
     manager:add_entry(nil, 4, "result 4")
 
-    eq(3, manager.worst_acceptable_score)
+    eq(3, manager:worst_acceptable_score())
   end)
 
   it("should update worst score in all prepend case", function()
@@ -151,6 +140,6 @@ describe("process_result", function()
     eq(3, called_count)
 
     eq("better result", manager:get_entry(1))
-    eq(4, manager.worst_acceptable_score)
+    eq(4, manager:worst_acceptable_score())
   end)
 end)

scratch/benchmark.lua

@@ -0,0 +1,49 @@
+local bench = require "plenary.benchmark"
+local fzf = require "fzf_lib"
+local CEntryManager = require "telescope.c_entry_manager"
+local EntryManager = require "telescope.entry_manager"
+
+local function lines_from(file)
+  local lines = {}
+  for line in io.lines(file) do
+    lines[#lines + 1] = line
+  end
+  return lines
+end
+
+local function filter(manager, prompt, lines)
+  local slab = fzf.allocate_slab()
+  local p = fzf.parse_pattern(prompt, 0)
+  for _, line in ipairs(lines) do
+    manager:add_entry({}, fzf.get_score(line, p, slab), { value = line, display = line, ordinal = line })
+  end
+  fzf.free_pattern(p)
+  fzf.free_slab(slab)
+
+  return manager:num_results()
+end
+
+local lines = lines_from "../telescope-fzf-native.nvim/files"
+
+local max = 10000
+
+bench("lua vs c ffi", {
+  warmup = 3,
+  runs = 10,
+  fun = {
+    {
+      "c ffi",
+      function()
+        local c_manager = CEntryManager:new(max)
+        filter(c_manager, "fzf.c", lines)
+      end,
+    },
+    {
+      "lua",
+      function()
+        local manager = EntryManager:new(max)
+        filter(manager, "fzf.c", lines)
+      end,
+    },
+  },
+})