perf(git): run git log sync with bounded count

lua/git/log.lua

@@ -6,44 +6,57 @@ local util = require("util")
 local M = {}
 
 local LOG_FORMAT = "%h %ad {%an}%d %s"
+local DEFAULT_MAX_COUNT = 1000
+
+---@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.show(opts)
+    opts = opts or {}
+    local max_count = opts.max_count
+    if max_count == nil then
+        max_count = DEFAULT_MAX_COUNT
+    end
 
-function M.show()
     local _, worktree = repo.resolve_cwd()
     if not worktree then
         log.warning("not in a git repository")
         return
     end
 
+    local cmd = {
+        "git",
+        "log",
+        "--graph",
+        "--all",
+        "--decorate",
+        "--date=short",
+        "--format=format:" .. LOG_FORMAT,
+    }
+    if max_count > 0 then
+        table.insert(cmd, "--max-count=" .. max_count)
+    end
+
+    local result = vim.system(cmd, { cwd = worktree, text = true }):wait()
+    if result.code ~= 0 then
+        log.error("git log failed: %s", vim.trim(result.stderr or ""))
+        return
+    end
+
     local buf = git.new_scratch()
     vim.b[buf].git_worktree = worktree
-
-    vim.system(
-        {
-            "git",
-            "log",
-            "--graph",
-            "--all",
-            "--decorate",
-            "--date=short",
-            "--format=format:" .. LOG_FORMAT,
-        },
-        { cwd = worktree, text = true },
-        vim.schedule_wrap(function(result)
-            if not vim.api.nvim_buf_is_valid(buf) then
-                return
-            end
-            if result.code ~= 0 then
-                log.error("git log failed: %s", vim.trim(result.stderr or ""))
-                return
-            end
-            local lines = util.split_lines(result.stdout or "")
-            vim.bo[buf].modifiable = true
-            vim.api.nvim_buf_set_lines(buf, 0, -1, false, lines)
-            vim.bo[buf].modifiable = false
-            vim.bo[buf].modified = false
-            vim.bo[buf].filetype = "gitlog"
-        end)
+    vim.bo[buf].modifiable = true
+    vim.api.nvim_buf_set_lines(
+        buf,
+        0,
+        -1,
+        false,
+        util.split_lines(result.stdout or "")
     )
+    vim.bo[buf].modifiable = false
+    vim.bo[buf].modified = false
+    vim.bo[buf].filetype = "gitlog"
 end
 
 return M