Windows,Bazel client: check embedded tools faster

The Bazel client on Windows is now 50% faster to
check the embedded tools than it was before.

Results:
- Linux: 20 ms -> 6 ms
- Windows: 294 ms -> 133 ms

Measurements were done with n=10 runs and a hot
server, using blaze::GetMillisecondsMonotonic().

Previously the client performed the same tasks
multiple times while trying to determine if a path
was a good extracted binary. (E.g. converted the
path to Windows format multiple times, checked if
it was a directory twice, opened the path twice.)

Now the client performes these tasks only once,
e.g. it converts path once and stats only once.

See https://github.com/bazelbuild/bazel/issues/5444

Closes #5445.

PiperOrigin-RevId: 201913758

2 files changed, 39 insertions, 17 deletions

diff --git a/src/test/cpp/util/file_test.cc b/src/test/cpp/util/file_test.cc
index 9683d9dcbe..a7eb9c7614 100644
--- a/src/test/cpp/util/file_test.cc
+++ b/src/test/cpp/util/file_test.cc
@@ -148,37 +148,31 @@ TEST(FileTest, TestMtimeHandling) {
   string tempdir(tempdir_cstr);
 
   std::unique_ptr<IFileMtime> mtime(CreateFileMtime());
-  bool actual = false;
-  ASSERT_TRUE(mtime->GetIfInDistantFuture(tempdir, &actual));
-  ASSERT_FALSE(actual);
-
+  // Assert that a directory is always untampered with. (We do
+  // not care about directories' mtimes.)
+  ASSERT_TRUE(mtime->IsUntampered(tempdir));
   // Create a new file, assert its mtime is not in the future.
   string file(JoinPath(tempdir, "foo.txt"));
   ASSERT_TRUE(WriteFile("hello", 5, file));
-  ASSERT_TRUE(mtime->GetIfInDistantFuture(file, &actual));
-  ASSERT_FALSE(actual);
+  ASSERT_FALSE(mtime->IsUntampered(file));
   // Set the file's mtime to the future, assert that it's so.
   ASSERT_TRUE(mtime->SetToDistantFuture(file));
-  ASSERT_TRUE(mtime->GetIfInDistantFuture(file, &actual));
-  ASSERT_TRUE(actual);
-  // Overwrite the file, resetting its mtime, assert that GetIfInDistantFuture
-  // notices.
+  ASSERT_TRUE(mtime->IsUntampered(file));
+  // Overwrite the file, resetting its mtime, assert that
+  // IsUntampered notices.
   ASSERT_TRUE(WriteFile("world", 5, file));
-  ASSERT_TRUE(mtime->GetIfInDistantFuture(file, &actual));
-  ASSERT_FALSE(actual);
+  ASSERT_FALSE(mtime->IsUntampered(file));
   // Set it to the future again so we can reset it using SetToNow.
   ASSERT_TRUE(mtime->SetToDistantFuture(file));
-  ASSERT_TRUE(mtime->GetIfInDistantFuture(file, &actual));
-  ASSERT_TRUE(actual);
+  ASSERT_TRUE(mtime->IsUntampered(file));
   // Assert that SetToNow resets the timestamp.
   ASSERT_TRUE(mtime->SetToNow(file));
-  ASSERT_TRUE(mtime->GetIfInDistantFuture(file, &actual));
-  ASSERT_FALSE(actual);
+  ASSERT_FALSE(mtime->IsUntampered(file));
   // Delete the file and assert that we can no longer set or query its mtime.
   ASSERT_TRUE(UnlinkPath(file));
   ASSERT_FALSE(mtime->SetToNow(file));
   ASSERT_FALSE(mtime->SetToDistantFuture(file));
-  ASSERT_FALSE(mtime->GetIfInDistantFuture(file, &actual));
+  ASSERT_FALSE(mtime->IsUntampered(file));
 }
 
 TEST(FileTest, TestRenameDirectory) {
diff --git a/src/test/cpp/util/file_windows_test.cc b/src/test/cpp/util/file_windows_test.cc
index 7bef9cf593..c048e07950 100644
--- a/src/test/cpp/util/file_windows_test.cc
+++ b/src/test/cpp/util/file_windows_test.cc
@@ -34,6 +34,8 @@
 #error("This test should only be run on Windows")
 #endif  // !defined(_WIN32) && !defined(__CYGWIN__)
 
+#define TOSTRING(x) #x
+
 namespace blaze_util {
 
 using bazel::windows::CreateJunction;
@@ -297,4 +299,30 @@ TEST_F(FileWindowsTest, TestMakeCanonical) {
   ASSERT_EQ(dircanon, symcanon);
 }
 
+TEST_F(FileWindowsTest, TestMtimeHandling) {
+  const char* tempdir_cstr = getenv("TEST_TMPDIR");
+  ASSERT_NE(tempdir_cstr, nullptr);
+  ASSERT_NE(tempdir_cstr[0], 0);
+  string tempdir(tempdir_cstr);
+
+  string target(JoinPath(tempdir, "target" TOSTRING(__LINE__)));
+  wstring wtarget;
+  EXPECT_TRUE(AsWindowsPath(target, &wtarget, nullptr));
+  EXPECT_TRUE(CreateDirectoryW(wtarget.c_str(), NULL));
+
+  std::unique_ptr<IFileMtime> mtime(CreateFileMtime());
+  // Assert that a directory is always a good embedded binary. (We do not care
+  // about directories' mtimes.)
+  ASSERT_TRUE(mtime.get()->IsUntampered(target));
+  // Assert that junctions whose target exists are "good" embedded binaries.
+  string sym(JoinPath(tempdir, "junc" TOSTRING(__LINE__)));
+  CREATE_JUNCTION(sym, target);
+  ASSERT_TRUE(mtime.get()->IsUntampered(sym));
+  // Assert that checking fails for non-existent directories and dangling
+  // junctions.
+  EXPECT_TRUE(RemoveDirectoryW(wtarget.c_str()));
+  ASSERT_FALSE(mtime.get()->IsUntampered(target));
+  ASSERT_FALSE(mtime.get()->IsUntampered(sym));
+}
+
 }  // namespace blaze_util