Add support for custom pagers, e.g. *Delta*

README.md

@@ -33,6 +33,7 @@ Here's an example spec for [Lazy](https://github.com/folke/lazy.nvim), but you'r
   dependencies = {
     "nvim-lua/plenary.nvim",         -- required
     "sindrets/diffview.nvim",        -- optional - Diff integration
+    "m00qek/baleia.nvim",            -- optional - Required for a custom log pager
 
     -- Only one of these is needed.
     "nvim-telescope/telescope.nvim", -- optional
@@ -90,6 +91,8 @@ neogit.setup {
   -- Show relative date by default. When set, use `strftime` to display dates
   commit_date_format = nil,
   log_date_format = nil,
+  -- When set, used to format the diff. Requires *baleia* to colorize text with ANSI escape sequences. An example for `Delta` is `{ 'delta', '--width', '117' }`. For `Delta`, hyperlinks must be disabled in its git config section, for text to be colorized properly. It's recommended to set `disable_context_highlighting = true`, otherwise when the cursor is in the hunk, we lose background highlighting
+  log_pager = nil,
   -- Show message with spinning animation when a git command is running.
   process_spinner = false,
   -- Used to generate URL's for branch popup action "pull request".

doc/neogit.txt

@@ -109,6 +109,11 @@ to Neovim users.
     -- Show relative date by default. When set, use `strftime` to display dates
     commit_date_format = nil,
     log_date_format = nil,
+    -- When set, used to format the diff. Requires `baleia` to colorize text with ANSI escape sequences. An example for
+    -- `Delta` is `{ 'delta', '--width', '117' }`. For `Delta`, hyperlinks must be disabled in its git config section,
+    -- for text to be colorized properly. It's recommended to set `disable_context_highlighting = true`, otherwise when
+    -- the cursor is in the hunk, we lose background highlighting
+    log_pager = nil,
     -- Used to generate URL's for branch popup action "pull request".
     git_services = {
         ["github.com"] = "https://github.com/${owner}/${repository}/compare/${branch_name}?expand=1",

lua/neogit/buffers/common.lua

@@ -25,21 +25,16 @@ M.Diff = Component.new(function(diff)
   }, { foldable = true, folded = false, context = true })
 end)
 
--- Use vim iter api?
 M.DiffHunks = Component.new(function(diff)
-  local hunk_props = vim
-    .iter(diff.hunks)
-    :map(function(hunk)
-      hunk.content = vim.iter(diff.lines):slice(hunk.diff_from + 1, hunk.diff_to):totable()
-
-      return {
-        header = diff.lines[hunk.diff_from],
-        content = hunk.content,
-        hunk = hunk,
-        folded = hunk._folded,
-      }
-    end)
-    :totable()
+  local hunk_props = {}
+  for i, hunk in ipairs(diff.hunks) do
+    table.insert(hunk_props, {
+      header = diff.lines[hunk.diff_from],
+      content = diff.pager_contents[i],
+      hunk = hunk,
+      folded = hunk._folded,
+    })
+  end
 
   return col.tag("DiffContent") {
     col.tag("DiffInfo")(map(diff.info, text)),
@@ -88,7 +83,13 @@ M.Hunk = Component.new(function(props)
   return col.tag("Hunk")({
     text.line_hl("NeogitHunkHeader")(props.header),
     col.tag("HunkContent")(map(props.content, HunkLine)),
-  }, { foldable = true, folded = props.folded or false, context = true, hunk = props.hunk })
+  }, {
+    ansi_hl = config.values.log_pager ~= nil,
+    foldable = true,
+    folded = props.folded or false,
+    context = true,
+    hunk = props.hunk,
+  })
 end)
 
 M.List = Component.new(function(props)

lua/neogit/config.lua

@@ -306,6 +306,7 @@ end
 ---@field graph_style? NeogitGraphStyle Style for graph
 ---@field commit_date_format? string Commit date format
 ---@field log_date_format? string Log date format
+---@field log_pager? [string] Log pager
 ---@field disable_hint? boolean Remove the top hint in the Status buffer
 ---@field disable_context_highlighting? boolean Disable context highlights based on cursor position
 ---@field disable_signs? boolean Special signs to draw for sections etc. in Neogit
@@ -359,6 +360,7 @@ function M.get_default_values()
     graph_style = "ascii",
     commit_date_format = nil,
     log_date_format = nil,
+    log_pager = nil,
     process_spinner = false,
     filewatcher = {
       enabled = true,

lua/neogit/lib/buffer.lua

@@ -151,6 +151,26 @@ function Buffer:set_line_highlights(highlights)
   end
 end
 
+function Buffer:set_ansi_highlights(highlights)
+  for _, hl in ipairs(highlights) do
+    local first_line, last_line = unpack(hl)
+    local text = self:get_lines(first_line, last_line, false)
+
+    for i, line in ipairs(text) do
+      if line:match("\27%[0K\27%[0m$") then
+        -- Handle "Erase in Line". We don't support coloring the rest of the line.
+        line = line:gsub("\27%[0K\27%[0m$", "")
+        if i < #text then
+          text[i + 1] = "\27[0m" .. text[i + 1]
+        end
+      end
+      text[i] = line
+    end
+
+    vim.g.baleia.buf_set_lines(self.handle, first_line, last_line, false, text)
+  end
+end
+
 function Buffer:set_folds(folds)
   self:set_window_option("foldmethod", "manual")
 

lua/neogit/lib/git/diff.lua

@@ -1,6 +1,7 @@
 local a = require("plenary.async")
 local git = require("neogit.lib.git")
 local util = require("neogit.lib.util")
+local config = require("neogit.config")
 local logger = require("neogit.logger")
 
 local insert = table.insert
@@ -18,6 +19,7 @@ local sha256 = vim.fn.sha256
 ---@field info table
 ---@field stats table
 ---@field hunks Hunk
+---@field pager_contents string[]
 ---
 ---@class DiffStats
 ---@field additions number
@@ -213,13 +215,49 @@ local function build_hunks(lines)
   return hunks
 end
 
+---@param diff_header string[]
+---@param lines string[]
+---@param hunks Hunk[]
+---@return string[][]
+local function build_pager_contents(diff_header, lines, hunks)
+  local res = {}
+  local jobs = {}
+  vim.iter(hunks):each(function(hunk)
+    local header = lines[hunk.diff_from]
+    local content = vim.list_slice(lines, hunk.diff_from + 1, hunk.diff_to)
+    if config.values.log_pager == nil then
+      insert(res, content)
+      return
+    end
+
+    local job = vim.system(config.values.log_pager, { stdin = true })
+    for _, part in ipairs { diff_header, { header }, content } do
+      for _, line in ipairs(part) do
+        job:write(line .. "\n")
+      end
+    end
+    job:write()
+    insert(jobs, job)
+  end)
+
+  if config.values.log_pager ~= nil then
+    vim.iter(jobs):each(function(job)
+      local content = vim.split(job:wait().stdout, "\n")
+      insert(res, content)
+    end)
+  end
+
+  return res
+end
+
 ---@param raw_diff string[]
 ---@param raw_stats string[]
 ---@return Diff
 local function parse_diff(raw_diff, raw_stats)
   local header, start_idx = build_diff_header(raw_diff)
   local lines = build_lines(raw_diff, start_idx)
   local hunks = build_hunks(lines)
+  local pager_contents = build_pager_contents(header, lines, hunks)
   local kind, info = build_kind(header)
   local file = build_file(header, kind)
   local stats = parse_diff_stats(raw_stats or {})
@@ -231,6 +269,7 @@ local function parse_diff(raw_diff, raw_stats)
     info = info,
     stats = stats,
     hunks = hunks,
+    pager_contents = pager_contents,
   }
 end
 

lua/neogit/lib/ui/component.lua

@@ -13,6 +13,7 @@ local default_component_options = {
 
 ---@class ComponentOptions
 ---@field line_hl string
+---@field ansi_hl boolean
 ---@field highlight string
 ---@field align_right integer|nil
 ---@field padding_left integer

lua/neogit/lib/ui/init.lua

@@ -686,6 +686,7 @@ function Ui:update()
     self.buf:set_highlights(renderer.buffer.highlight)
     self.buf:set_extmarks(renderer.buffer.extmark)
     self.buf:set_line_highlights(renderer.buffer.line_highlight)
+    self.buf:set_ansi_highlights(renderer.buffer.ansi_highlight)
     self.buf:set_folds(renderer.buffer.fold)
 
     self.statuscolumn = {}

lua/neogit/lib/ui/renderer.lua

@@ -65,6 +65,7 @@ end
 ---@field line string[]
 ---@field highlight table[]
 ---@field line_highlight table[]
+---@field ansi_highlight table[]
 ---@field extmark table[]
 ---@field fold table[]
 
@@ -93,6 +94,7 @@ function Renderer:new(layout, buffer)
       line = {},
       highlight = {},
       line_highlight = {},
+      ansi_highlight = {},
       extmark = {},
       fold = {},
     },
@@ -194,6 +196,13 @@ function Renderer:_render_child(child)
     table.insert(self.buffer.line_highlight, { #self.buffer.line - 1, line_hl })
   end
 
+  if child.options.ansi_hl then
+    table.insert(self.buffer.ansi_highlight, {
+      #self.buffer.line - (child.position.row_end - child.position.row_start),
+      #self.buffer.line,
+    })
+  end
+
   if child.options.virtual_text then
     table.insert(self.buffer.extmark, {
       self.namespace,

tests/specs/neogit/lib/git/log_spec.lua

@@ -230,6 +230,67 @@ describe("lib.git.log.parse", function()
             " ",
             " ---@param selection Selection",
           },
+          pager_contents = {
+            {
+              " ---@param first_line number",
+              " ---@param last_line number",
+              " ---@param partial boolean",
+              "----@return SelectedHunk[],string[]",
+              "+---@return SelectedHunk[]",
+              " function M.get_item_hunks(item, first_line, last_line, partial)",
+              "   if item.folded or item.hunks == nil then",
+              "-    return {}, {}",
+              "+    return {}",
+              "   end",
+              " ",
+              "   local hunks = {}",
+              "-  local lines = {}",
+              " ",
+              "   for _, h in ipairs(item.hunks) do",
+              "-    -- Transform to be relative to the current item/file",
+              "-    local first_line = first_line - item.first",
+              "-    local last_line = last_line - item.first",
+              "-",
+              "-    if h.diff_from <= last_line and h.diff_to >= first_line then",
+              "-      -- Relative to the hunk",
+              "+    if h.first <= last_line and h.last >= first_line then",
+              "       local from, to",
+              "+",
+              "       if partial then",
+              "-        from = h.diff_from + math.max(first_line - h.diff_from, 0)",
+              "-        to = math.min(last_line, h.diff_to)",
+              "+        local length = last_line - first_line",
+              "+        from = h.diff_from + math.max((first_line - item.first) - h.diff_from, 0)",
+              "+        to = from + length",
+              "       else",
+              "         from = h.diff_from + 1",
+              "         to = h.diff_to",
+              "       end",
+              " ",
+              "       local hunk_lines = {}",
+              "-",
+              "       for i = from, to do",
+              "         table.insert(hunk_lines, item.diff.lines[i])",
+              "       end",
+            },
+            {
+              "       setmetatable(o, o)",
+              " ",
+              "       table.insert(hunks, o)",
+              "-",
+              "-      for i = from, to do",
+              "-        table.insert(lines, item.diff.lines[i + h.diff_from])",
+              "-      end",
+              "     end",
+              "   end",
+              " ",
+              "-  return hunks, lines",
+              "+  return hunks",
+              " end",
+              " ",
+              " ---@param selection Selection",
+            },
+          },
           stats = {
             additions = 0,
             deletions = 0,
@@ -317,6 +378,19 @@ describe("lib.git.log.parse", function()
             ' of this software and associated documentation files (the "Software"), to deal',
             " in the Software without restriction, including without limitation the rights",
           },
+          pager_contents = {
+            {
+              " MIT License",
+              " ",
+              "+hello",
+              " Copyright (c) 2020 TimUntersberger",
+              " ",
+              "+world",
+              " Permission is hereby granted, free of charge, to any person obtaining a copy",
+              ' of this software and associated documentation files (the "Software"), to deal',
+              " in the Software without restriction, including without limitation the rights",
+            },
+          },
           stats = {
             additions = 0,
             deletions = 0,