post: simplify and rename totalSize

...and add some more logging. Related to #45.

post.js

@@ -19,7 +19,7 @@ async function main() {
 
       if (accessible) {
         core.info('Checking cache size');
-        const size = await totalSize(cache_path);
+        const size = await dirSize(cache_path);
         const size_limit = core.getInput('cache-size-limit') * 1024 * 1024; // MiB -> bytes
         if (size_limit !== 0 && size > size_limit) {
           core.info(`Cache directory reached ${size} bytes, exceeding limit of ${size_limit} bytes; clearing cache`);
@@ -35,6 +35,8 @@ async function main() {
         const name = prefix + github.context.runId;
         core.info('Saving Zig cache');
         await cache.saveCache([cache_path], name);
+      } else {
+        core.info('Zig cache directory is inaccessible; nothing to save');
       }
     }
   } catch (err) {
@@ -42,18 +44,18 @@ async function main() {
   }
 }
 
-async function totalSize(p) {
+async function dirSize(dir_path) {
   try {
-    const stat = await fs.stat(p);
-    if (stat.isFile()) return stat.size;
-    if (stat.isDirectory()) {
-      let total = 0;
-      for (const entry of await fs.readdir(p)) {
-        total += await totalSize(path.join(p, entry));
+    let total = 0;
+    for (const ent of await fs.readdir(dir_path, { withFileTypes: true, recursive: true })) {
+      if (ent.isFile()) {
+        try {
+          const stat = await fs.stat(path.join(ent.parentPath, ent.name));
+          total += stat.size;
+        } catch {}
       }
-      return total;
     }
-    return 0;
+    return total;
   } catch {
     return 0;
   }