feat: Add tags (#219)

4 files changed, 165 insertions, 4 deletions

diff --git a/lua/telescope/builtin/init.lua b/lua/telescope/builtin/init.lua
index 2336a42..80c1f3f 100644
--- a/lua/telescope/builtin/init.lua
+++ b/lua/telescope/builtin/init.lua
@@ -923,4 +923,54 @@ builtin.keymaps = function(opts)
   }):find()
 end
 
+builtin.tags = function(opts)
+  opts = opts or {}
+
+  local ctags_file = opts.ctags_file or 'tags'
+
+  if not vim.loop.fs_open(vim.fn.expand(ctags_file), "r", 438) then
+    print('Tags file does not exists. Create one with ctags -R')
+    return
+  end
+
+  local fd = assert(vim.loop.fs_open(vim.fn.expand(ctags_file), "r", 438))
+  local stat = assert(vim.loop.fs_fstat(fd))
+  local data = assert(vim.loop.fs_read(fd, stat.size, 0))
+  assert(vim.loop.fs_close(fd))
+
+  local results = vim.split(data, '\n')
+
+  pickers.new(opts,{
+    prompt = 'Tags',
+    finder = finders.new_table {
+      results = results,
+      entry_maker = make_entry.gen_from_ctags(opts),
+    },
+    previewer = previewers.ctags.new(opts),
+    sorter = conf.generic_sorter(opts),
+    attach_mappings = function(prompt_bufnr)
+      actions._goto_file_selection:enhance {
+        post = function()
+          local selection = actions.get_selected_entry(prompt_bufnr)
+
+          local scode = string.gsub(selection.scode, '[$]$', '')
+          scode = string.gsub(scode, [[\\]], [[\]])
+          scode = string.gsub(scode, [[\/]], [[/]])
+          scode = string.gsub(scode, '[*]', [[\*]])
+
+          vim.cmd('norm! gg')
+          vim.fn.search(scode)
+          vim.cmd('norm! zz')
+        end,
+      }
+      return true
+    end
+  }):find()
+end
+
+builtin.current_buffer_tags = function(opts)
+  opts = opts or {}
+  return builtin.tags(vim.tbl_extend("force", {only_current_file = true, hide_filename = true}, opts))
+end
+
 return builtin
diff --git a/lua/telescope/make_entry.lua b/lua/telescope/make_entry.lua
index 906eb95..57344ab 100644
--- a/lua/telescope/make_entry.lua
+++ b/lua/telescope/make_entry.lua
@@ -559,4 +559,73 @@ function make_entry.gen_from_vimoptions(opts)
   end
 end
 
+function make_entry.gen_from_ctags(opts)
+  opts = opts or {}
+
+  local cwd = vim.fn.expand(opts.cwd or vim.fn.getcwd())
+  local current_file = path.normalize(vim.fn.expand('%'), cwd)
+
+  local display_items = {
+    { width = 30 },
+    { remaining = true },
+  }
+
+  if opts.show_line then
+    table.insert(display_items, 2, { width = 30 })
+  end
+
+  local displayer = entry_display.create {
+    separator = " │ ",
+    items = display_items,
+  }
+
+  local make_display = function(entry)
+    local filename
+    if not opts.hide_filename then
+      if opts.shorten_path then
+        filename = path.shorten(entry.filename)
+      else
+        filename = entry.filename
+      end
+    end
+
+    local scode
+    if opts.show_line then
+      scode = entry.scode
+    end
+
+    return displayer {
+      filename,
+      entry.tag,
+      scode,
+    }
+  end
+
+  return function(line)
+    if line == '' or line:sub(1, 1) == '!' then
+      return nil
+    end
+
+    local tag, file, scode = string.match(line, '([^\t]+)\t([^\t]+)\t/^\t?(.*)/;"\t+.*')
+
+    if opts.only_current_file and file ~= current_file then
+      return nil
+    end
+
+    return {
+      valid = true,
+
+      ordinal = file .. ': ' .. tag,
+      display = make_display,
+      scode = scode,
+      tag = tag,
+
+      filename = file,
+
+      col = 1,
+      lnum = 1,
+    }
+  end
+end
+
 return make_entry
diff --git a/lua/telescope/pickers/entry_display.lua b/lua/telescope/pickers/entry_display.lua
index c661b89..aef3047 100644
--- a/lua/telescope/pickers/entry_display.lua
+++ b/lua/telescope/pickers/entry_display.lua
@@ -43,8 +43,8 @@ end
 
 local function truncate(str, len)
   -- TODO: This doesn't handle multi byte chars...
-  if vim.fn.strdisplaywidth(str) > len - 1 then
-    str = str:sub(1, len)
+  if vim.fn.strdisplaywidth(str) > len then
+    str = str:sub(1, len - 1)
     str = str .. "…"
   end
   return str
@@ -68,8 +68,10 @@ entry_display.create = function(configuration)
 
   return function(self, picker)
     local results = {}
-    for k, v in ipairs(self) do
-      table.insert(results, generator[k](v, picker))
+    for i = 1, table.getn(generator) do
+      if self[i] ~= nil then
+        table.insert(results, generator[i](self[i], picker))
+      end
     end
 
     return table.concat(results, configuration.separator or "│")
diff --git a/lua/telescope/previewers.lua b/lua/telescope/previewers.lua
index d85d149..29442fa 100644
--- a/lua/telescope/previewers.lua
+++ b/lua/telescope/previewers.lua
@@ -400,6 +400,46 @@ previewers.vimgrep = defaulter(function(opts)
   }
 end, {})
 
+previewers.ctags = defaulter(function(opts)
+  return previewers.new {
+    setup = function()
+      return {}
+    end,
+
+    teardown = function(self)
+      if self.state and self.state.hl_id then
+        pcall(vim.fn.matchdelete, self.state.hl_id, self.state.hl_win)
+        self.state.hl_id = nil
+      end
+    end,
+
+    preview_fn = function(self, entry, status)
+      with_preview_window(status, nil, function()
+        local scode = string.gsub(entry.scode, '[$]$', '')
+        scode = string.gsub(scode, [[\\]], [[\]])
+        scode = string.gsub(scode, [[\/]], [[/]])
+        scode = string.gsub(scode, '[*]', [[\*]])
+
+        local new_bufnr = vim.fn.bufnr(entry.filename, true)
+        vim.fn.bufload(new_bufnr)
+
+        vim.api.nvim_win_set_buf(status.preview_win, new_bufnr)
+        vim.api.nvim_win_set_option(status.preview_win, 'wrap', false)
+        vim.api.nvim_win_set_option(status.preview_win, 'winhl', 'Normal:Normal')
+        vim.api.nvim_win_set_option(status.preview_win, 'signcolumn', 'no')
+        vim.api.nvim_win_set_option(status.preview_win, 'foldlevel', 100)
+
+        pcall(vim.fn.matchdelete, self.state.hl_id, self.state.hl_win)
+        vim.fn.search(scode)
+        vim.cmd "norm zz"
+
+        self.state.hl_win = status.preview_win
+        self.state.hl_id = vim.fn.matchadd('Search', scode)
+      end)
+    end
+  }
+end, {})
+
 previewers.qflist = defaulter(function(opts)
   opts = opts or {}