diffs.nvim/lua/diffs/git.lua
Barrett Ruth f5a090baae
perf: cache repo root and harden async paths (#100)
## Problem

`get_repo_root()` shells out to `git rev-parse` on every call, causing
4-6
redundant subprocesses per `gdiff_file()` invocation. Three other minor
issues: `highlight_vim_syntax()` leaks a scratch buffer if
`nvim_buf_call`
errors, `lib.ensure()` silently drops callbacks during download so hunks
highlighted mid-download permanently miss intra-line highlights, and the
debounce timer callback can operate on a deleted buffer.

## Solution

Cache `get_repo_root()` results by parent directory — repo roots don't
change within a session. Wrap `nvim_buf_call` and `nvim_buf_delete` in
pcall so the scratch buffer is always cleaned up. Replace the early
`callback(nil)` in `lib.ensure()` with a pending callback queue that
fires
once the download completes. Guard the debounce timer callback with
`nvim_buf_is_valid`.
2026-02-09 12:39:13 -05:00

119 lines
3 KiB
Lua

local M = {}
local repo_root_cache = {}
---@param filepath string
---@return string?
function M.get_repo_root(filepath)
local dir = vim.fn.fnamemodify(filepath, ':h')
if repo_root_cache[dir] ~= nil then
return repo_root_cache[dir]
end
local result = vim.fn.systemlist({ 'git', '-C', dir, 'rev-parse', '--show-toplevel' })
if vim.v.shell_error ~= 0 then
return nil
end
repo_root_cache[dir] = result[1]
return result[1]
end
---@param revision string
---@param filepath string
---@return string[]?, string?
function M.get_file_content(revision, filepath)
local repo_root = M.get_repo_root(filepath)
if not repo_root then
return nil, 'not in a git repository'
end
local rel_path = vim.fn.fnamemodify(filepath, ':.')
if vim.startswith(filepath, repo_root) then
rel_path = filepath:sub(#repo_root + 2)
end
local result = vim.fn.systemlist({ 'git', '-C', repo_root, 'show', revision .. ':' .. rel_path })
if vim.v.shell_error ~= 0 then
return nil, 'failed to get file at revision: ' .. revision
end
return result, nil
end
---@param filepath string
---@return string?
function M.get_relative_path(filepath)
local repo_root = M.get_repo_root(filepath)
if not repo_root then
return nil
end
if vim.startswith(filepath, repo_root) then
return filepath:sub(#repo_root + 2)
end
return vim.fn.fnamemodify(filepath, ':.')
end
---@param filepath string
---@return string[]?, string?
function M.get_index_content(filepath)
local repo_root = M.get_repo_root(filepath)
if not repo_root then
return nil, 'not in a git repository'
end
local rel_path = M.get_relative_path(filepath)
if not rel_path then
return nil, 'could not determine relative path'
end
local result = vim.fn.systemlist({ 'git', '-C', repo_root, 'show', ':0:' .. rel_path })
if vim.v.shell_error ~= 0 then
return nil, 'file not in index'
end
return result, nil
end
---@param filepath string
---@return string[]?, string?
function M.get_working_content(filepath)
if vim.fn.filereadable(filepath) ~= 1 then
return nil, 'file not readable'
end
local lines = vim.fn.readfile(filepath)
return lines, nil
end
---@param filepath string
---@return boolean
function M.file_exists_in_index(filepath)
local repo_root = M.get_repo_root(filepath)
if not repo_root then
return false
end
local rel_path = M.get_relative_path(filepath)
if not rel_path then
return false
end
vim.fn.system({ 'git', '-C', repo_root, 'ls-files', '--stage', '--', rel_path })
return vim.v.shell_error == 0
end
---@param revision string
---@param filepath string
---@return boolean
function M.file_exists_at_revision(revision, filepath)
local repo_root = M.get_repo_root(filepath)
if not repo_root then
return false
end
local rel_path = M.get_relative_path(filepath)
if not rel_path then
return false
end
vim.fn.system({ 'git', '-C', repo_root, 'cat-file', '-e', revision .. ':' .. rel_path })
return vim.v.shell_error == 0
end
return M