Actually run compdb asynchronously

Turns out vim.schedule() only defers calling the function until main
event loop has some free cycles but can still block the UI, just a bit
later. This patch replaces the external command invoked in the callback
passed into vim.schedule() with vim.fn.jobstart() and moves the other
code into job callbacks.

lua/build.lua

@@ -26,37 +26,41 @@ function build.set_dir(dirname)
 
   build.dir = build_dir
 
-  -- Invoke async function to avoid blocking the UI
+  echo('Processing compile_commands.json with compdb ...', 'DiagnosticInfo')
-  vim.schedule(function()
+  local compile_commands = current_dir .. '/compile_commands.json'
-    echo('Processing compile_commands.json with compdb ...', 'DiagnosticInfo')
+  -- Post-process compile_commands.json with compdb as an async job to avoid
+  -- blocking the user interface
+  vim.fn.jobstart(
+    'compdb -p ' .. build.dir .. ' list > ' .. compile_commands, {
 
-    -- Post-process compile_commands.json with compdb
+      -- Restart clangd language server
-    local compile_commands = current_dir .. '/compile_commands.json'
+      -- TODO: Configure cmake language server?
-    local output = vim.fn.systemlist(
+      on_exit = function()
-      'compdb -p ' .. build.dir .. ' list > ' .. compile_commands)
+        vim.cmd [[ LspRestart clangd ]]
+        echo('Build directory selected: ' .. dirname, 'DiagnosticInfo')
+      end,
 
-    -- Remove any lines containing a compdb warning
+      -- Display any error messages to the user
-    local error = {}
+      on_stderr = function(_, output, _)
-    local warning = 'WARNING:compdb'
+        -- Remove any lines containing a compdb warning
-    for _, line in ipairs(output) do
+        local error = {}
-      if string.sub(line, 1, #warning) ~= warning then
+        local warning = 'WARNING:compdb'
-        table.insert(error, line)
+        for _, line in ipairs(output) do
-      end
+          if string.sub(line, 1, #warning) ~= warning then
-    end
+            table.insert(error, line)
+          end
+        end
 
-    -- Display the error message if there was one
+        -- Display the error message if there was one
-    if table.maxn(error) > 0 then
+        if table.maxn(error) > 0 then
-      echo(vim.fn.join(error, '\n'), 'Error')
+          echo(vim.fn.join(error, '\n'), 'Error')
-      return
+          return
-    end
+        end
+      end,
 
-    -- TODO: Configure cmake language server?
+      stderr_buffered = true,
-
+    }
-    -- Restart clangd language server
+  )
-    vim.cmd [[ LspRestart clangd ]]
-
-    echo('Build directory selected: ' .. dirname, 'DiagnosticInfo')
-  end)
 end
 
 function build.select_dir(callback)

lua/mappings.lua

@@ -43,7 +43,3 @@ vim.keymap.set('n', 'Q', '<nop>', {noremap = true})
 
 -- Undo neovim's default mapping of Y to y$
 vim.cmd('unmap Y')
-
--- Move visually selected blocks around
-vim.keymap.set('v', 'J', ":move '>+1<CR>gv=gv'")
-vim.keymap.set('v', 'K', ":move '<-2<CR>gv=gv'")