Windows JNI: refactorings

In this change:

- rename //src/main/native:windows_jni_utils to
//src/main/native:windows_jni_lib and make it
visible to //src/main/cpp:__subpackages__ because
we will use some methods there from this library

- move AutoHandle into windows_util.h, we'll use
it from blaze_util_windows.cc / file_windows.cc
later

See bazelbuild#2107

--
PiperOrigin-RevId: 144946842
MOS_MIGRATED_REVID=144946842

src/main/native/BUILD

@@ -63,10 +63,13 @@ cc_binary(
 )
 
 cc_library(
-    name = "windows_jni_utils",
+    name = "windows_jni_lib",
     srcs = ["windows_util.cc"],
     hdrs = ["windows_util.h"],
-    visibility = ["//src/test/native:__pkg__"],
+    visibility = [
+        "//src/main/cpp:__subpackages__",
+        "//src/test/native:__pkg__",
+    ],
 )
 
 genrule(

src/main/native/windows_processes.cc

@@ -79,16 +79,6 @@ struct NativeProcess {
         error_("") {}
 };
 
-struct AutoHandle {
-  AutoHandle() : handle(INVALID_HANDLE_VALUE) {}
-  ~AutoHandle() {
-    CloseHandle(handle);  // handles INVALID_HANDLE_VALUE
-    handle = INVALID_HANDLE_VALUE;
-  }
-
-  HANDLE handle;
-};
-
 class JavaByteArray {
  public:
   JavaByteArray(JNIEnv* env, jbyteArray java_array)
@@ -196,10 +186,10 @@ Java_com_google_devtools_build_lib_windows_WindowsProcesses_nativeCreateProcess(
   // created. If this was not so, operations on these file handles would not
   // return immediately if the process is terminated.
   // Therefore we make these handles auto-closing (by using AutoHandle).
-  AutoHandle stdin_process;
-  AutoHandle stdout_process;
-  AutoHandle stderr_process;
-  AutoHandle thread;
+  windows_util::AutoHandle stdin_process;
+  windows_util::AutoHandle stdout_process;
+  windows_util::AutoHandle stderr_process;
+  windows_util::AutoHandle thread;
   PROCESS_INFORMATION process_info = {0};
   STARTUPINFOA startup_info = {0};
   JOBOBJECT_EXTENDED_LIMIT_INFORMATION job_info = {0};

src/main/native/windows_util.h

@@ -11,12 +11,12 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
-//
-// INTERNAL header file for use by C++ code in this package.
 
 #ifndef BAZEL_SRC_MAIN_NATIVE_WINDOWS_UTIL_H__
 #define BAZEL_SRC_MAIN_NATIVE_WINDOWS_UTIL_H__
 
+#include <windows.h>
+
 #include <functional>
 #include <memory>
 #include <string>
@@ -28,6 +28,18 @@ using std::string;
 using std::unique_ptr;
 using std::wstring;
 
+// A wrapper for the `HANDLE` type that calls CloseHandle in its d'tor.
+struct AutoHandle {
+  AutoHandle(HANDLE _handle = INVALID_HANDLE_VALUE) : handle(_handle) {}
+
+  ~AutoHandle() {
+    ::CloseHandle(handle);  // succeeds if handle == INVALID_HANDLE_VALUE
+    handle = INVALID_HANDLE_VALUE;
+  }
+
+  HANDLE handle;
+};
+
 string GetLastErrorString(const string& cause);
 
 // Computes a path suitable as the executable part in CreateProcessA's cmdline.

src/test/native/BUILD

@@ -17,11 +17,11 @@ cc_test(
     }),
     deps = select({
         "//src:windows": [
-            "//src/main/native:windows_jni_utils",
+            "//src/main/native:windows_jni_lib",
             "//third_party:gtest",
         ],
         "//src:windows_msvc": [
-            "//src/main/native:windows_jni_utils",
+            "//src/main/native:windows_jni_lib",
             "//third_party:gtest",
         ],
         "//conditions:default": [],