watcher/linux/inotify: opt. common path of one event to avoid re-hashing potentially large path strings, and avoid null checks which have already been made by the caller

Author: Will

devel/include/detail/wtr/watcher/adapter/linux/inotify/watch.hpp

@@ -195,7 +195,10 @@ inline auto parse_ev = [](
   using ev_et = enum ev::effect_type;
   auto pathof = [&](inotify_event const* const m)
   { return known_pathof_wd_or_default(dm, m->wd) / m->name; };
-  auto pt = in->mask & IN_ISDIR ? ev_pt::dir : ev_pt::file;
+  auto in_path = pathof(in);
+  auto pt = in->mask & IN_ISDIR ? ev_pt::dir
+          : is_symlink(in_path) ? ev_pt::sym_link
+                                : ev_pt::file;
   auto et = in->mask & IN_CREATE ? ev_et::create
           : in->mask & IN_DELETE ? ev_et::destroy
           : in->mask & IN_MOVE   ? ev_et::rename
@@ -205,15 +208,15 @@ inline auto parse_ev = [](
   { return b && b->cookie && b->cookie == a->cookie && et == ev_et::rename; };
   auto isfromto = [](auto* a, auto* b) -> bool
   { return (a->mask & IN_MOVED_FROM) && (b->mask & IN_MOVED_TO); };
-  auto one = [&](auto* a, auto* next) -> parsed
-  { return {ev(pathof(a), et, pt), next}; };
+  auto one = [&](auto* next) -> parsed
+  { return {ev(in_path, et, pt), next}; };
   auto assoc = [&](auto* a, auto* b) -> parsed
   { return {ev(ev(pathof(a), et, pt), ev(pathof(b), et, pt)), peek(b, tail)}; };
   auto next = peek(in, tail);
-  return ! isassoc(in, next) ? one(in, next)
+  return ! isassoc(in, next) ? one(next)
        : isfromto(in, next)  ? assoc(in, next)
        : isfromto(next, in)  ? assoc(next, in)
-                             : (*ec = 1, one(in, next));
+                             : (*ec = 1, one(next));
 };
 
 struct defer_dm_rm_wd {

include/wtr/watcher.hpp

@@ -1478,14 +1478,10 @@ inline auto parse_ev = [](
   using ev_et = enum ev::effect_type;
   auto pathof = [&](inotify_event const* const m)
   { return known_pathof_wd_or_default(dm, m->wd) / m->name; };
-  auto calc_pt = [&](inotify_event const* const ev_ptr) -> ev_pt
-  {
-    // Return other type if pointer is null
-    if (! ev_ptr) return ev_pt::other;
-    return ev_ptr->mask & IN_ISDIR    ? ev_pt::dir
-         : is_symlink(pathof(ev_ptr)) ? ev_pt::sym_link
-                                      : ev_pt::file;
-  };
+  auto in_path = pathof(in);
+  auto pt = in->mask & IN_ISDIR ? ev_pt::dir
+          : is_symlink(in_path) ? ev_pt::sym_link
+                                : ev_pt::file;
   auto et = in->mask & IN_CREATE ? ev_et::create
           : in->mask & IN_DELETE ? ev_et::destroy
           : in->mask & IN_MOVE   ? ev_et::rename
@@ -1495,20 +1491,15 @@ inline auto parse_ev = [](
   { return b && b->cookie && b->cookie == a->cookie && et == ev_et::rename; };
   auto isfromto = [](auto* a, auto* b) -> bool
   { return (a->mask & IN_MOVED_FROM) && (b->mask & IN_MOVED_TO); };
-  auto one = [&](auto* a, auto* next) -> parsed
-  { return {ev(pathof(a), et, calc_pt(a)), next}; };
+  auto one = [&](auto* next) -> parsed
+  { return {ev(in_path, et, pt), next}; };
   auto assoc = [&](auto* a, auto* b) -> parsed
-  {
-    auto pt_b = calc_pt(b);
-    return {
-      ev(ev(pathof(a), et, pt_b), ev(pathof(b), et, pt_b)),
-      peek(b, tail)};
-  };
+  { return {ev(ev(pathof(a), et, pt), ev(pathof(b), et, pt)), peek(b, tail)}; };
   auto next = peek(in, tail);
-  return ! isassoc(in, next) ? one(in, next)
+  return ! isassoc(in, next) ? one(next)
        : isfromto(in, next)  ? assoc(in, next)
        : isfromto(next, in)  ? assoc(next, in)
-                             : (*ec = 1, one(in, next));
+                             : (*ec = 1, one(next));
 };
 
 struct defer_dm_rm_wd {