feat: support viewing the diff via other pagers, e.g. *Delta*

Add the `log_pager` option, which can be set to `delta`.

Author: stevenxxiu

README.md

@@ -90,6 +90,8 @@ 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.
+  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",

doc/neogit.txt

@@ -91,6 +91,7 @@ TODO: Detail what these do
     graph_style = "ascii",
     commit_date_format = nil,
     log_date_format = nil,
+    log_pager = nil,
     filewatcher = {
       enabled = true,
     },

lua/neogit/buffers/common.lua

@@ -1,3 +1,5 @@
+local Job = require("plenary.job")
+
 local Ui = require("neogit.lib.ui")
 local Component = require("neogit.lib.ui.component")
 local util = require("neogit.lib.util")
@@ -25,22 +27,45 @@ 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()
+      local header = diff.lines[hunk.diff_from]
+      local content = vim.list_slice(diff.lines, hunk.diff_from + 1, hunk.diff_to)
+      local job = nil
+      if config.values.log_pager ~= nil then
+        job = Job:new {
+          command = config.values.log_pager[1],
+          args = vim.list_slice(config.values.log_pager, 2),
+        }
+        job:start()
+        for _, part in ipairs { diff.header, { header }, content } do
+          for _, line in ipairs(part) do
+            job:send(line .. "\n")
+          end
+        end
+        job.stdin:close()
+      end
 
       return {
-        header = diff.lines[hunk.diff_from],
-        content = hunk.content,
+        header = header,
+        content = content,
+        job = job,
         hunk = hunk,
         folded = hunk._folded,
       }
     end)
     :totable()
 
+  if config.values.log_pager ~= nil then
+    vim.iter(hunk_props):each(function(hunk)
+      hunk.job:wait()
+      hunk.content = hunk.job:result()
+      hunk.job = nil
+    end)
+  end
+
   return col.tag("DiffContent") {
     col.tag("DiffInfo")(map(diff.info, text)),
     col.tag("HunkList")(map(hunk_props, M.Hunk)),

lua/neogit/config.lua

@@ -302,6 +302,7 @@ 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
@@ -355,6 +356,7 @@ function M.get_default_values()
     graph_style = "ascii",
     commit_date_format = nil,
     log_date_format = nil,
+    log_pager = nil,
     process_spinner = true,
     filewatcher = {
       enabled = true,

lua/neogit/lib/buffer.lua

@@ -139,8 +139,21 @@ function Buffer:set_extmarks(extmarks)
 end
 
 function Buffer:set_line_highlights(highlights)
+  local line_ansi_colorized = {}
+
   for _, hl in ipairs(highlights) do
-    self:add_line_highlight(unpack(hl))
+    local line_nr, hl_group = unpack(hl)
+    if hl_group == "NeogitDiffContext" then
+      if not line_ansi_colorized[line_nr] then
+        local text = self:get_line(line_nr + 1)
+        vim.g.baleia.buf_set_lines(self.handle, line_nr, line_nr + 1, false, text)
+        line_ansi_colorized[line_nr] = true
+      end
+    end
+
+    if not line_ansi_colorized[line_nr] then
+      self:add_line_highlight(unpack(hl))
+    end
   end
 end
 

lua/neogit/lib/git/diff.lua

@@ -12,6 +12,7 @@ local sha256 = vim.fn.sha256
 ---@field staged_stats fun(): DiffStagedStats
 ---
 ---@class Diff
+---@field header string[]
 ---@field kind string
 ---@field lines string[]
 ---@field file string
@@ -225,6 +226,7 @@ local function parse_diff(raw_diff, raw_stats)
   local stats = parse_diff_stats(raw_stats or {})
 
   return { ---@type Diff
+    header = header,
     kind = kind,
     lines = lines,
     file = file,