refactor(git): gitlog as gitlog:// URI singleton, fix synthetic-URI cwd resolve

lua/git/log.lua

@@ -5,24 +5,12 @@ local M = {}
 
 local LOG_FORMAT = "%h %ad {%an}%d %s"
 local DEFAULT_MAX_COUNT = 1000
+local URI_PREFIX = "gitlog://"
 
----@class ow.Git.LogOpts
----@field max_count integer?  cap on commits to show. Nil uses the default, <= 0 means "all"
-
----@param opts ow.Git.LogOpts?
-function M.open(opts)
-    opts = opts or {}
-    local max_count = opts.max_count
-    if max_count == nil then
-        max_count = DEFAULT_MAX_COUNT
-    end
-
-    local _, worktree = repo.resolve_cwd()
-    if not worktree then
-        util.warning("not in a git repository")
-        return
-    end
-
+---@param worktree string
+---@param max_count integer
+---@return string?
+local function fetch(worktree, max_count)
     local cmd = {
         "git",
         "log",
@@ -35,21 +23,74 @@ function M.open(opts)
     if max_count > 0 then
         table.insert(cmd, "--max-count=" .. max_count)
     end
+    return util.exec(cmd, { cwd = worktree })
+end
 
-    local stdout = util.exec(cmd, { cwd = worktree })
+---@param buf integer
+local function populate(buf)
+    local worktree = vim.b[buf].git_worktree
+    local max_count = vim.b[buf].git_log_max_count or DEFAULT_MAX_COUNT
+    local stdout = fetch(worktree, max_count)
     if not stdout then
         return
     end
-
-    -- `hide` keeps the log around when the user navigates into a commit
-    -- via `<CR>` (which replaces the current buffer); `<C-^>` jumps back.
-    local buf = util.new_scratch({ bufhidden = "hide" })
-    vim.b[buf].git_worktree = worktree
     vim.bo[buf].modifiable = true
     vim.api.nvim_buf_set_lines(buf, 0, -1, false, util.split_lines(stdout))
     vim.bo[buf].modifiable = false
     vim.bo[buf].modified = false
-    vim.bo[buf].filetype = "gitlog"
+end
+
+---BufReadCmd handler for `gitlog://<worktree>` URIs.
+---@param buf integer
+function M.read_uri(buf)
+    local name = vim.api.nvim_buf_get_name(buf)
+    local worktree = name:sub(#URI_PREFIX + 1)
+    if worktree == "" then
+        return
+    end
+
+    vim.b[buf].git_worktree = worktree
+    vim.bo[buf].swapfile = false
+    vim.bo[buf].bufhidden = "hide"
+    vim.bo[buf].buftype = "nofile"
+    -- Skip the assignment when ft is already set so re-runs don't
+    -- re-fire `FileType` autocmds (ftplugin reload, treesitter attach).
+    if vim.bo[buf].filetype ~= "gitlog" then
+        vim.bo[buf].filetype = "gitlog"
+    end
+
+    populate(buf)
+end
+
+---@class ow.Git.LogOpts
+---@field max_count integer?  cap on commits to show. Nil uses the default, <= 0 means "all"
+
+---@param opts ow.Git.LogOpts?
+function M.open(opts)
+    opts = opts or {}
+    local _, worktree = repo.resolve_cwd()
+    if not worktree then
+        util.warning("not in a git repository")
+        return
+    end
+
+    local buf = vim.fn.bufadd(URI_PREFIX .. worktree)
+    vim.b[buf].git_worktree = worktree
+    vim.b[buf].git_log_max_count = opts.max_count or DEFAULT_MAX_COUNT
+    local was_loaded = vim.api.nvim_buf_is_loaded(buf)
+
+    local win = vim.fn.bufwinid(buf)
+    if win == -1 then
+        util.place_buf(buf, nil)
+    else
+        vim.api.nvim_set_current_win(win)
+    end
+
+    -- `place_buf` triggers `bufload` -> `read_uri` for a fresh buffer.
+    -- An already-loaded buffer needs an explicit refresh.
+    if was_loaded then
+        populate(buf)
+    end
 end
 
 return M