refactor: move show log command to VCSAdapter (#276)

* feat(vcs): Added a `to_range()` method to the Rev class.

Co-authored-by: Sindre T. Strøm <sindrets@gmail.com>

Author: zegervdv

lua/diffview/scene/views/diff/diff_view.lua

@@ -120,7 +120,7 @@ end
 function DiffView:post_open()
   vim.cmd("redraw")
 
-  self.commit_log_panel = CommitLogPanel(self.adapter.ctx.toplevel, {
+  self.commit_log_panel = CommitLogPanel(self.adapter, {
     name = ("diffview://%s/log/%d/%s"):format(self.adapter.ctx.dir, self.tabpage, "commit_log"),
   })
 

lua/diffview/scene/views/diff/listeners.lua

@@ -101,18 +101,14 @@ return function(view)
       end
     end,
     open_commit_log = function()
-      if (view.left.type == RevType.STAGE and view.right.type == RevType.LOCAL)
-        or (
-          view.left.type == RevType.COMMIT
-          and vim.tbl_contains({ RevType.STAGE, RevType.LOCAL }, view.right.type)
-          and view.left:is_head(view.adapter)
-        ) then
+      local range = view.adapter.Rev.to_range(view.left, view.right)
+
+      if not range or view.left:is_head(view.adapter) then
         utils.info("Changes not commited yet. No log available for these changes.")
         return
       end
 
-      local rev_arg = ("%s..%s"):format(view.left.commit, view.right.commit or "HEAD")
-      view.commit_log_panel:update(rev_arg)
+      view.commit_log_panel:update(range)
     end,
     toggle_stage_entry = function()
       if not (view.left.type == RevType.STAGE and view.right.type == RevType.LOCAL) then

lua/diffview/scene/views/file_history/file_history_view.lua

@@ -38,7 +38,7 @@ function FileHistoryView:init(opt)
 end
 
 function FileHistoryView:post_open()
-  self.commit_log_panel = CommitLogPanel(self.adapter.ctx.toplevel, {
+  self.commit_log_panel = CommitLogPanel(self.adapter, {
     name = ("diffview://%s/log/%d/%s"):format(self.adapter.ctx.dir, self.tabpage, "commit_log"),
   })
 

lua/diffview/scene/views/file_history/listeners.lua

@@ -138,7 +138,7 @@ return function(view)
       if file then
         local entry = view.panel:find_entry(file)
         if entry then
-          view.commit_log_panel:update(entry.commit.hash .. "^!")
+          view.commit_log_panel:update(view.adapter.Rev.to_range(entry.commit.hash))
         end
       end
     end,

lua/diffview/ui/panels/commit_log_panel.lua

@@ -8,7 +8,7 @@ local utils = require("diffview.utils")
 local M = {}
 
 ---@class CommitLogPanel : Panel
----@field git_toplevel string
+---@field adapter VCSAdapter
 ---@field args string[]
 ---@field job_out string[]
 local CommitLogPanel = oop.create_class("CommitLogPanel", Panel)
@@ -47,15 +47,15 @@ end
 ---@field args string[]
 ---@field name string
 
----@param git_toplevel string
+---@param adapter VCSAdapter
 ---@param opt CommitLogPanelSpec
-function CommitLogPanel:init(git_toplevel, opt)
+function CommitLogPanel:init(adapter, opt)
   CommitLogPanel:super().init(self, {
     bufname = opt.name,
     config = opt.config or get_user_config().commit_log_panel.win_config,
   })
 
-  self.git_toplevel = git_toplevel
+  self.adapter = adapter
   self.args = opt.args or { "-n256" }
 
   self:on_autocmd("BufWinEnter" , {
@@ -73,14 +73,9 @@ CommitLogPanel.update = async.void(function(self, args)
   end
 
   Job:new({
-    command = "git",
-    args = utils.vec_join(
-      "log",
-      "--first-parent",
-      "--stat",
-      args or self.args
-    ),
-    cwd = self.git_toplevel,
+    command = self.adapter:bin(),
+    args = self.adapter:get_log_args(args or self.args),
+    cwd = self.adapter.ctx.toplevel,
     on_exit = vim.schedule_wrap(function(job)
       if job.code ~= 0 then
         utils.err("Failed to open log!")

lua/diffview/vcs/adapter.lua

@@ -173,6 +173,12 @@ function VCSAdapter:get_show_args(path, rev)
   oop.abstract_stub()
 end
 
+---@param args string[]
+---@return string[] args to show commit log message
+function VCSAdapter:get_log_args(args)
+  oop.abstract_stub()
+end
+
 ---@param range? { [1]: integer, [2]: integer }
 ---@param paths string[]
 ---@param args string[]

lua/diffview/vcs/adapters/git/init.lua

@@ -230,6 +230,10 @@ function GitAdapter:get_show_args(path, rev)
   return utils.vec_join(self:args(), "show", ("%s:%s"):format(rev and rev:object_name() or "", path))
 end
 
+function GitAdapter:get_log_args(args)
+  return utils.vec_join("log", "--first-parent", "--stat", args)
+end
+
 function GitAdapter:get_dir(path)
   local out, code = self:exec_sync({ "rev-parse", "--path-format=absolute", "--git-dir" }, path)
   if code ~= 0 then

lua/diffview/vcs/adapters/git/rev.lua

@@ -49,6 +49,35 @@ function GitRev:init(rev_type, revision, track_head)
   end
 end
 
+---@param rev_from GitRev|string
+---@param rev_to? GitRev|string
+---@return string?
+function GitRev.to_range(rev_from, rev_to)
+  if type(rev_from) ~= "string" and rev_from.type ~= RevType.COMMIT then
+    -- The range between either LOCAL or STAGE, and any other rev, will always
+    -- be empty.
+    return nil
+  end
+
+  local name_from = type(rev_from) == "string" and rev_from or rev_from:object_name()
+  local name_to
+
+  if rev_to then
+    if type(rev_to) == "string" then
+      name_to = rev_to
+    else
+      -- If the rev is either of type LOCAL or STAGE, just fall back to HEAD.
+      name_to = rev_to.type == RevType.COMMIT and rev_to:object_name() or "HEAD"
+    end
+  end
+
+  if not name_to then
+    return name_from .. "^!"
+  else
+    return name_from .. ".." .. name_to
+  end
+end
+
 ---@param name string
 ---@param adapter GitAdapter
 ---@return Rev?
@@ -85,8 +114,8 @@ end
 ---Determine if this rev is currently the head.
 ---@param adapter GitAdapter
 ---@return boolean?
-function Rev:is_head(adapter)
-  if not self.type == RevType.COMMIT then
+function GitRev:is_head(adapter)
+  if self.type ~= RevType.COMMIT then
     return false
   end
 

lua/diffview/vcs/rev.lua

@@ -66,6 +66,15 @@ end
 
 ---@diagnostic disable: unused-local, missing-return
 
+---Get the argument describing the range between the two given revs. If a
+---single rev is given, the returned argument describes the *range* of the
+---single commit pointed to by that rev.
+---@abstract
+---@param rev_from Rev|string
+---@param rev_to? Rev|string
+---@return string?
+function Rev.to_range(rev_from, rev_to) oop.abstract_stub() end
+
 ---@param name string
 ---@param adapter? VCSAdapter
 ---@return Rev?