Bazel,client: actually cache directory creations

Commit f5043d6
was incorrect in that it cached the file names,
not the directory names.

This commit fixes that. I verified that the number
of calls to ExtractBlazeZipProcessor::Process is
greater than the calls to MakeDirectories within
(1038 vs. 172 on Linux).

See #5444

Change-Id: I314bdc9337c9782a5ceaed7aac785a552b222b1f

Closes #5484.

Change-Id: I314bdc9337c9782a5ceaed7aac785a552b222b1f
PiperOrigin-RevId: 202314400

src/main/cpp/blaze.cc

@@ -893,12 +893,13 @@ class ExtractBlazeZipProcessor : public PureZipExtractorProcessor {
   void Process(const char *filename, const devtools_ijar::u4 attr,
                const devtools_ijar::u1 *data, const size_t size) override {
     string path = blaze_util::JoinPath(embedded_binaries_, filename);
+    string dirname = blaze_util::Dirname(path);
     // Performance optimization: memoize the paths we already created a
     // directory for, to spare a stat in attempting to recreate an already
     // existing directory. This optimization alone shaves off seconds from the
     // extraction time on Windows.
-    if (created_directories_.insert(path).second) {
-      if (!blaze_util::MakeDirectories(blaze_util::Dirname(path), 0777)) {
+    if (created_directories_.insert(dirname).second) {
+      if (!blaze_util::MakeDirectories(dirname, 0777)) {
         BAZEL_DIE(blaze_exit_code::INTERNAL_ERROR)
             << "couldn't create '" << path << "': " << GetLastErrorString();
       }