refactor(renderer): More ergonomic rendering API.

Author: sindrets

lua/diffview/hl.lua

@@ -339,11 +339,11 @@ function M.get_file_icon(name, ext, render_data, line_idx, offset)
   end
 
   if icon then
-    if hl then
+    if hl and render_data then
       render_data:add_hl(hl, line_idx, offset, offset + string.len(icon) + 1)
     end
 
-    return icon .. " "
+    return icon .. " ", hl
   end
 
   return ""

lua/diffview/renderer.lua

@@ -31,6 +31,7 @@ M.last_draw_time = 0
 ---@field parent RenderComponent
 ---@field lines string[]
 ---@field hl renderer.HlList
+---@field line_buffer string
 ---@field components RenderComponent[]
 ---@field lstart integer 0 indexed, Inclusive
 ---@field lend integer Exclusive
@@ -44,6 +45,7 @@ function RenderComponent:init(name)
   self.name = name or RenderComponent.next_uid()
   self.lines = {}
   self.hl = {}
+  self.line_buffer = ""
   self.components = {}
   self.lstart = -1
   self.lend = -1
@@ -132,9 +134,16 @@ function RenderComponent:remove_component(component)
   return false
 end
 
----@param line string
-function RenderComponent:add_line(line)
-  self.lines[#self.lines + 1] = line
+---@param line string?
+---@param hl_group string?
+function RenderComponent:add_line(line, hl_group)
+  if line and hl_group then
+    local first = #self.line_buffer
+    self:add_hl(hl_group, #self.lines, first, first + #line)
+  end
+
+  self.lines[#self.lines + 1] = self.line_buffer .. (line or "")
+  self.line_buffer = ""
 end
 
 ---@param group string
@@ -150,6 +159,23 @@ function RenderComponent:add_hl(group, line_idx, first, last)
   }
 end
 
+---@param text string
+---@param hl_group string?
+function RenderComponent:add_text(text, hl_group)
+  if hl_group then
+    local first = #self.line_buffer
+    self:add_hl(hl_group, #self.lines, first, first + #text)
+  end
+
+  self.line_buffer = self.line_buffer .. text
+end
+
+---Finalize current line
+function RenderComponent:ln()
+  self.lines[#self.lines + 1] = self.line_buffer
+  self.line_buffer = ""
+end
+
 function RenderComponent:clear()
   self.lines = {}
   self.hl = {}

lua/diffview/scene/views/diff/render.lua

@@ -8,57 +8,40 @@ local utils = require("diffview.utils")
 local function render_file(comp, show_path, depth)
   ---@type table
   local file = comp.context
-  local offset = 0
 
-  comp:add_hl(hl.get_git_hl(file.status), 0, 0, 1)
-  local s = file.status .. " "
+  comp:add_text(file.status .. " ", hl.get_git_hl(file.status))
+
   if depth then
-    s = s .. string.rep(" ", depth * 2 + 2)
+    comp:add_text(string.rep(" ", depth * 2 + 2))
   end
 
-  offset = #s
-  local icon = hl.get_file_icon(file.basename, file.extension, comp, 0, offset)
-
-  offset = offset + #icon
-  comp:add_hl("DiffviewFilePanelFileName", 0, offset, offset + #file.basename)
-  s = s .. icon .. file.basename
+  local icon, icon_hl = hl.get_file_icon(file.basename, file.extension)
+  comp:add_text(icon, icon_hl)
+  comp:add_text(file.basename, "DiffviewFilePanelFileName")
 
   if file.stats then
-    offset = #s + 1
-
     if file.stats.additions then
-      comp:add_hl("DiffviewFilePanelInsertions", 0, offset, offset + string.len(file.stats.additions))
-      offset = offset + string.len(file.stats.additions) + 2
-      comp:add_hl("DiffviewFilePanelDeletions", 0, offset, offset + string.len(file.stats.deletions))
-      s = s .. " " .. file.stats.additions .. ", " .. file.stats.deletions
+      comp:add_text(" " .. file.stats.additions, "DiffviewFilePanelInsertions")
+      comp:add_text(", ")
+      comp:add_text(tostring(file.stats.deletions), "DiffviewFilePanelDeletions")
     elseif file.stats.conflicts then
-      local conflicts
-
-      if file.stats.conflicts == 0 then
-        conflicts = config.get_config().signs.done
-        comp:add_hl("DiffviewFilePanelInsertions", 0, offset, offset + string.len(conflicts))
-      else
-        conflicts = tostring(file.stats.conflicts)
-        comp:add_hl("DiffviewFilePanelConflicts", 0, offset, offset + string.len(conflicts))
-      end
-
-      s = s .. " " .. conflicts
+      local has_conflicts = file.stats.conflicts > 0
+      comp:add_text(
+        " " .. (has_conflicts and file.stats.conflicts or config.get_config().signs.done),
+        has_conflicts and "DiffviewFilePanelConflicts" or "DiffviewFilePanelInsertions"
+      )
     end
   end
 
   if file.kind == "conflicting" and not (file.stats and file.stats.conflicts) then
-    offset = #s + 1
-    comp:add_hl("DiffviewFilePanelConflicts", 0, offset, offset + 1)
-    s = s .. " !"
+    comp:add_text(" !", "DiffviewFilePanelConflicts")
   end
 
   if show_path then
-    offset = #s + 1
-    comp:add_hl("DiffviewFilePanelPath", 0, offset, offset + #file.parent_path)
-    s = s .. " " .. file.parent_path
+    comp:add_text(" " .. file.parent_path, "DiffviewFilePanelPath")
   end
 
-  comp:add_line(s)
+  comp:ln()
 end
 
 ---@param comp RenderComponent
@@ -73,48 +56,45 @@ end
 ---@return string
 local function get_dir_status_text(ctx, tree_options)
   local folder_statuses = tree_options.folder_statuses
+
   if folder_statuses == "always" or (folder_statuses == "only_folded" and ctx.collapsed) then
     return ctx.status
   end
+
   return " "
 end
 
 ---@param depth integer
 ---@param comp RenderComponent
 local function render_file_tree_recurse(depth, comp)
   local conf = config.get_config()
-  local offset, s
 
   if comp.name == "file" then
     render_file(comp, false, depth)
     return
   end
-  if comp.name ~= "wrapper" then
-    return
-  end
+  if comp.name ~= "wrapper" then return end
 
   local dir = comp.components[1]
   ---@type table
   local ctx = dir.context
 
-  dir:add_hl(hl.get_git_hl(ctx.status), 0, 0, 1)
-  s = get_dir_status_text(ctx, conf.file_panel.tree_options) .. " "
-
-  s = s .. string.rep(" ", depth * 2)
-  offset = #s
+  dir:add_text(
+    get_dir_status_text(ctx, conf.file_panel.tree_options) .. " ",
+    hl.get_git_hl(ctx.status)
+  )
+  dir:add_text(string.rep(" ", depth * 2))
+  dir:add_text(ctx.collapsed and conf.signs.fold_closed or conf.signs.fold_open, "DiffviewNonText")
 
-  local fold = ctx.collapsed and conf.signs.fold_closed or conf.signs.fold_open
-  local icon = ""
   if conf.use_icons then
-    icon = " " .. (ctx.collapsed and conf.icons.folder_closed or conf.icons.folder_open)
+    dir:add_text(
+      " " .. (ctx.collapsed and conf.icons.folder_closed or conf.icons.folder_open) .. " ",
+      "DiffviewFolderSign"
+    )
   end
-  dir:add_hl("DiffviewNonText", 0, offset, offset + #fold)
-  dir:add_hl("DiffviewFolderSign", 0, offset + #fold + 1, offset + #fold + 1 + #icon)
-  s = string.format("%s%s%s ", s, fold, icon)
 
-  offset = #s
-  dir:add_hl("DiffviewFolderName", 0, offset, offset + #ctx.name)
-  dir:add_line(s .. ctx.name)
+  dir:add_text(ctx.name, "DiffviewFolderName")
+  dir:ln()
 
   if not ctx.collapsed then
     for i = 2, #comp.components do
@@ -154,51 +134,37 @@ return function(panel)
 
   ---@type RenderComponent
   local comp = panel.components.path.comp
-  local line_idx = 0
-  local s = utils.path:shorten(utils.path:vim_fnamemodify(panel.adapter.ctx.toplevel, ":~"), width - 6)
-  comp:add_hl("DiffviewFilePanelRootPath", line_idx, 0, #s)
-  comp:add_line(s)
 
-  local change_count
+  comp:add_line(
+    utils.path:shorten(utils.path:vim_fnamemodify(panel.adapter.ctx.toplevel, ":~"), width - 6),
+    "DiffviewFilePanelRootPath"
+  )
 
   if #panel.files.conflicting > 0 then
     comp = panel.components.conflicting.title.comp
-    line_idx = 0
-    s = "Conflicts"
-    comp:add_hl("DiffviewFilePanelTitle", line_idx, 0, #s)
-    change_count = "(" .. #panel.files.conflicting .. ")"
-    comp:add_hl("DiffviewFilePanelCounter", line_idx, #s + 1, #s + 1 + string.len(change_count))
-    s = s .. " " .. change_count
-    comp:add_line(s)
+    comp:add_text("Conflicts ", "DiffviewFilePanelTitle")
+    comp:add_text("(" .. #panel.files.conflicting .. ")", "DiffviewFilePanelCounter")
+    comp:ln()
 
     render_files(panel.listing_style, panel.components.conflicting.files.comp)
   end
 
   comp = panel.components.working.title.comp
-  line_idx = 0
-  if #panel.files.conflicting > 0 then
-    comp:add_line("")
-    line_idx = 1
-  end
-  s = "Changes"
-  comp:add_hl("DiffviewFilePanelTitle", line_idx, 0, #s)
-  change_count = "(" .. #panel.files.working .. ")"
-  comp:add_hl("DiffviewFilePanelCounter", line_idx, #s + 1, #s + 1 + string.len(change_count))
-  s = s .. " " .. change_count
-  comp:add_line(s)
+
+  if #panel.files.conflicting > 0 then comp:add_line() end
+
+  comp:add_text("Changes ", "DiffviewFilePanelTitle")
+  comp:add_text("(" .. #panel.files.working .. ")", "DiffviewFilePanelCounter")
+  comp:ln()
 
   render_files(panel.listing_style, panel.components.working.files.comp)
 
   if #panel.files.staged > 0 then
     comp = panel.components.staged.title.comp
-    comp:add_line("")
-    line_idx = 1
-    s = "Staged changes"
-    comp:add_hl("DiffviewFilePanelTitle", line_idx, 0, #s)
-    change_count = "(" .. #panel.files.staged .. ")"
-    comp:add_hl("DiffviewFilePanelCounter", line_idx, #s + 1, #s + 1 + string.len(change_count))
-    s = s .. " " .. change_count
-    comp:add_line(s)
+    comp:add_line()
+    comp:add_text("Staged changes ", "DiffviewFilePanelTitle")
+    comp:add_text("(" .. #panel.files.staged .. ")", "DiffviewFilePanelCounter")
+    comp:ln()
 
     render_files(panel.listing_style, panel.components.staged.files.comp)
   end
@@ -207,25 +173,15 @@ return function(panel)
     local extra_info = utils.vec_join({ panel.rev_pretty_name }, panel.path_args or {})
 
     comp = panel.components.info.title.comp
-    line_idx = 0
-    comp:add_line("")
-    line_idx = line_idx + 1
-
-    s = "Showing changes for:"
-    comp:add_hl("DiffviewFilePanelTitle", line_idx, 0, #s)
-    comp:add_line(s)
+    comp:add_line()
+    comp:add_line("Showing changes for:", "DiffviewFilePanelTitle")
 
     comp = panel.components.info.entries.comp
-    line_idx = 0
+
     for _, arg in ipairs(extra_info) do
       local relpath = utils.path:relative(arg, panel.adapter.ctx.toplevel)
-      if relpath == "" then
-        relpath = "."
-      end
-      s = utils.path:shorten(relpath, width - 5)
-      comp:add_hl("DiffviewFilePanelPath", line_idx, 0, #s)
-      comp:add_line(s)
-      line_idx = line_idx + 1
+      if relpath == "" then relpath = "." end
+      comp:add_line(utils.path:shorten(relpath, width - 5), "DiffviewFilePanelPath")
     end
   end
 end