From e0705b5d4a10570b4b781a5ecfc4f026b2f2cd4e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alvaro=20Mu=C3=B1oz?= <alvaro@pwntester.com>
Date: Wed, 30 Dec 2020 00:56:12 +0100
Subject: [PATCH] feat: append mode for previewers.utils.job_maker (#372)

---
 lua/telescope/previewers/buffer_previewer.lua | 37 +++++++++----------
 lua/telescope/previewers/utils.lua            | 22 ++++++++---
 2 files changed, 34 insertions(+), 25 deletions(-)

diff --git a/lua/telescope/previewers/buffer_previewer.lua b/lua/telescope/previewers/buffer_previewer.lua
index 39f3ad0..64cb5d5 100644
--- a/lua/telescope/previewers/buffer_previewer.lua
+++ b/lua/telescope/previewers/buffer_previewer.lua
@@ -350,12 +350,11 @@ previewers.man = defaulter(function(_)
     define_preview = function(self, entry, status)
       putils.with_preview_window(status, nil, function()
         local win_width = vim.api.nvim_win_get_width(self.state.winid)
-        putils.job_maker({'man', '-P', 'cat', entry.value},
-          { ["MANWIDTH"] = win_width },
-          entry.value,
-          self.state.bufnr,
-          self.state.bufname
-        )
+        putils.job_maker({'man', '-P', 'cat', entry.value}, self.state.bufnr, {
+          env = { ["MANWIDTH"] = win_width },
+          value = entry.value,
+          bufname = self.state.bufname
+        })
         putils.regex_highlighter(_, 'man')
        end)
     end
@@ -417,7 +416,11 @@ previewers.git_branch_log = defaulter(function(_)
         local cmd = { 'git', '-P', 'log', '--graph', '--pretty=format:%h -%d %s (%cr)',
           '--abbrev-commit', '--date=relative', entry.value
         }
-        putils.job_maker(cmd, nil, entry.value, self.state.bufnr, self.state.bufname, highlight_buffer)
+        putils.job_maker(cmd, self.state.bufnr, {
+          value = entry.value,
+          bufname = self.state.bufname,
+          callback = highlight_buffer
+        })
       end)
     end
   }
@@ -431,12 +434,10 @@ previewers.git_commit_diff = defaulter(function(_)
 
     define_preview = function(self, entry, status)
       putils.with_preview_window(status, nil, function()
-        putils.job_maker({ 'git', '-P', 'diff', entry.value .. '^!' },
-          nil,
-          entry.value,
-          self.state.bufnr,
-          self.state.bufname
-        )
+        putils.job_maker({ 'git', '-P', 'diff', entry.value .. '^!' }, self.state.bufnr, {
+          value = entry.value,
+          bufname = self.state.bufname
+        })
         putils.regex_highlighter(_, 'diff')
       end)
     end
@@ -451,12 +452,10 @@ previewers.git_file_diff = defaulter(function(_)
 
     define_preview = function(self, entry, status)
       putils.with_preview_window(status, nil, function()
-        putils.job_maker({ 'git', '-P', 'diff', entry.value },
-          nil,
-          entry.value,
-          self.state.bufnr,
-          self.state.bufname
-        )
+        putils.job_maker({ 'git', '-P', 'diff', entry.value }, self.state.bufnr, {
+          value = entry.value,
+          bufname = self.state.bufname
+        })
         putils.regex_highlighter(_, 'diff')
       end)
     end
diff --git a/lua/telescope/previewers/utils.lua b/lua/telescope/previewers/utils.lua
index d584577..475083a 100644
--- a/lua/telescope/previewers/utils.lua
+++ b/lua/telescope/previewers/utils.lua
@@ -22,20 +22,30 @@ end
 
 -- API helper functions for buffer previewer
 --- Job maker for buffer previewer
-utils.job_maker = function(cmd, env, value, bufnr, bufname, callback)
-  if bufname ~= value then
+utils.job_maker = function(cmd, bufnr, opts)
+  opts = opts or {}
+  opts.mode = opts.mode or "insert"
+  -- bufname and value are optional
+  -- if passed, they will be use as the cache key
+  -- if any of them are missing, cache will be skipped
+  if opts.bufname ~= opts.value or not opts.bufname or not opts.value then
     local command = table.remove(cmd, 1)
     Job:new({
       command = command,
       args = cmd,
-      env = env,
+      env = opts.env,
       on_exit = vim.schedule_wrap(function(j)
-        vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, j:result())
-        if callback then callback(bufnr, j:result()) end
+        if opts.mode == "append" then
+          local count = vim.api.nvim_buf_line_count(bufnr)
+          vim.api.nvim_buf_set_lines(bufnr, count, -1, false, j:result())
+        elseif opts.mode == "insert" then
+          vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, j:result())
+        end
+        if opts.callback then opts.callback(bufnr, j:result()) end
       end)
     }):start()
   else
-    if callback then callback(bufnr) end
+    if opts.callback then opts.callback(bufnr) end
   end
 end