feat(git): ambient progress for long-running :G subcommands

lua/git/history.lua

@@ -0,0 +1,58 @@
+local util = require("git.util")
+
+local M = {}
+
+local BUF_NAME = "githistory://log"
+
+---@type integer?
+local cached_buf
+
+---@return integer
+local function get_buf()
+    if cached_buf and vim.api.nvim_buf_is_valid(cached_buf) then
+        return cached_buf
+    end
+    local buf = vim.api.nvim_create_buf(false, true)
+    pcall(vim.api.nvim_buf_set_name, buf, BUF_NAME)
+    util.setup_scratch(buf, { bufhidden = "hide" })
+    cached_buf = buf
+    return buf
+end
+
+---@param args string[]
+---@param lines string[]
+function M.append(args, lines)
+    if #lines == 0 then
+        return
+    end
+    local buf = get_buf()
+    local count = vim.api.nvim_buf_line_count(buf)
+    local first = vim.api.nvim_buf_get_lines(buf, 0, 1, false)[1] or ""
+    local empty = count == 1 and first == ""
+    local payload = { "$ git " .. table.concat(args, " ") }
+    vim.list_extend(payload, lines)
+    vim.bo[buf].modifiable = true
+    if empty then
+        vim.api.nvim_buf_set_lines(buf, 0, -1, false, payload)
+    else
+        table.insert(payload, 1, "")
+        vim.api.nvim_buf_set_lines(buf, count, count, false, payload)
+    end
+    vim.bo[buf].modifiable = false
+    vim.bo[buf].modified = false
+end
+
+function M.open()
+    local buf = get_buf()
+    local win = vim.fn.bufwinid(buf)
+    if win ~= -1 then
+        vim.api.nvim_set_current_win(win)
+    else
+        util.place_buf(buf, nil)
+        win = vim.api.nvim_get_current_win()
+    end
+    local last = vim.api.nvim_buf_line_count(buf)
+    vim.api.nvim_win_set_cursor(win, { last, 0 })
+end
+
+return M