Windows, JNI, refactor: co-locate all JNI code

Move JNI code from windows_file_operations.cc to
windows_processes.cc, so all the JNI code is now
in the latter.

This lets us expose windows_file_operations.* to
the Bazel client (via the ":windows_jni_lib"
target), so we can finally share file handling
logic between the Bazel client and the JNI
library.

See https://github.com/bazelbuild/bazel/issues/2107

--
PiperOrigin-RevId: 145063140
MOS_MIGRATED_REVID=145063140

2 files changed, 45 insertions, 64 deletions

diff --git a/src/main/native/windows_file_operations.cc b/src/main/native/windows_file_operations.cc
index 610ae95707..e9e561eeb8 100644
--- a/src/main/native/windows_file_operations.cc
+++ b/src/main/native/windows_file_operations.cc
@@ -12,12 +12,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#include <jni.h>
 #include <windows.h>
 
 #include <memory>
-#include <string>
-#include <type_traits>  // static_assert
 
 #include "src/main/native/windows_file_operations.h"
 #include "src/main/native/windows_util.h"
@@ -26,11 +23,6 @@ namespace windows_util {
 
 using std::unique_ptr;
 
-// Ensure we can safely cast (const) jchar* to LP(C)WSTR.
-// This is true with MSVC but usually not with GCC.
-static_assert(sizeof(jchar) == sizeof(WCHAR),
-              "jchar and WCHAR should be the same size");
-
 int IsJunctionOrDirectorySymlink(const WCHAR* path) {
   DWORD attrs = ::GetFileAttributesW(path);
   if (attrs == INVALID_FILE_ATTRIBUTES) {
@@ -55,60 +47,4 @@ bool GetLongPath(const WCHAR* path, unique_ptr<WCHAR[]>* result) {
   return true;
 }
 
-static void MaybeReportLastError(string reason, JNIEnv* env,
-                                 jobjectArray error_msg_holder) {
-  if (error_msg_holder != nullptr &&
-      env->GetArrayLength(error_msg_holder) > 0) {
-    std::string error_str = windows_util::GetLastErrorString(reason);
-    jstring error_msg = env->NewStringUTF(error_str.c_str());
-    env->SetObjectArrayElement(error_msg_holder, 0, error_msg);
-  }
-}
-
 }  // namespace windows_util
-
-extern "C" JNIEXPORT jint JNICALL
-Java_com_google_devtools_build_lib_windows_WindowsFileOperations_nativeIsJunction(
-    JNIEnv* env, jclass clazz, jstring path, jobjectArray error_msg_holder) {
-  bool report_error =
-      error_msg_holder != nullptr && env->GetArrayLength(error_msg_holder) > 0;
-  const jchar* wpath = env->GetStringChars(path, nullptr);
-  int result = windows_util::IsJunctionOrDirectorySymlink((LPCWSTR)wpath);
-  env->ReleaseStringChars(path, wpath);
-  if (result == windows_util::IS_JUNCTION_ERROR && report_error) {
-    // Getting the string's characters again in UTF8 encoding is
-    // easier than converting `wpath` using `wcstombs(3)`.
-    const char* path_cstr = env->GetStringUTFChars(path, nullptr);
-    windows_util::MaybeReportLastError(
-        std::string("GetFileAttributes(") + path_cstr + ")", env,
-        error_msg_holder);
-    env->ReleaseStringUTFChars(path, path_cstr);
-  }
-  return result;
-}
-
-extern "C" JNIEXPORT jboolean JNICALL
-Java_com_google_devtools_build_lib_windows_WindowsFileOperations_nativeGetLongPath(
-    JNIEnv* env, jclass clazz, jstring path, jobjectArray result_holder,
-    jobjectArray error_msg_holder) {
-  const jchar* cpath = nullptr;
-  cpath = env->GetStringChars(path, nullptr);
-  std::unique_ptr<WCHAR[]> result;
-  bool success =
-      windows_util::GetLongPath(reinterpret_cast<const WCHAR*>(cpath), &result);
-  env->ReleaseStringChars(path, cpath);
-  if (!success) {
-    const char* path_cstr = env->GetStringUTFChars(path, nullptr);
-    windows_util::MaybeReportLastError(
-        std::string("GetLongPathName(") + path_cstr + ")", env,
-        error_msg_holder);
-    env->ReleaseStringUTFChars(path, path_cstr);
-    return JNI_FALSE;
-  }
-  std::wstring wresult(result.get());
-  env->SetObjectArrayElement(
-      result_holder, 0,
-      env->NewString(reinterpret_cast<const jchar*>(wresult.c_str()),
-                     wresult.size()));
-  return JNI_TRUE;
-}
diff --git a/src/main/native/windows_processes.cc b/src/main/native/windows_processes.cc
index 284b4e8c60..0a085c2da1 100644
--- a/src/main/native/windows_processes.cc
+++ b/src/main/native/windows_processes.cc
@@ -19,6 +19,7 @@
 #include <jni.h>
 #include <stdlib.h>
 #include <string.h>
+#include <wchar.h>
 #include <windows.h>
 
 #include <atomic>
@@ -27,6 +28,7 @@
 #include <string>
 #include <type_traits>  // static_assert
 
+#include "src/main/native/windows_file_operations.h"
 #include "src/main/native/windows_util.h"
 
 // Ensure we can safely cast (const) jchar* to (const) WCHAR* and LP(C)WSTR.
@@ -118,6 +120,16 @@ static bool NestedJobsSupported() {
     version_info.dwMajorVersion == 6 && version_info.dwMinorVersion >= 2;
 }
 
+static void MaybeReportLastError(const std::string& reason, JNIEnv* env,
+                                 jobjectArray error_msg_holder) {
+  if (error_msg_holder != nullptr &&
+      env->GetArrayLength(error_msg_holder) > 0) {
+    std::string error_str = windows_util::GetLastErrorString(reason);
+    jstring error_msg = env->NewStringUTF(error_str.c_str());
+    env->SetObjectArrayElement(error_msg_holder, 0, error_msg);
+  }
+}
+
 static std::string GetJavaUTFString(JNIEnv* env, jstring str) {
   std::string result;
   if (str != nullptr) {
@@ -580,3 +592,36 @@ Java_com_google_devtools_build_lib_windows_WindowsProcesses_nativeStreamGetLastE
   stream->error_ = "";
   return result;
 }
+
+extern "C" JNIEXPORT jint JNICALL
+Java_com_google_devtools_build_lib_windows_WindowsFileOperations_nativeIsJunction(
+    JNIEnv* env, jclass clazz, jstring path, jobjectArray error_msg_holder) {
+  int result = windows_util::IsJunctionOrDirectorySymlink(
+      GetJavaWstring(env, path).c_str());
+  if (result == windows_util::IS_JUNCTION_ERROR) {
+    MaybeReportLastError(
+        std::string("GetFileAttributes(") + GetJavaUTFString(env, path) + ")",
+        env, error_msg_holder);
+  }
+  return result;
+}
+
+extern "C" JNIEXPORT jboolean JNICALL
+Java_com_google_devtools_build_lib_windows_WindowsFileOperations_nativeGetLongPath(
+    JNIEnv* env, jclass clazz, jstring path, jobjectArray result_holder,
+    jobjectArray error_msg_holder) {
+  std::unique_ptr<WCHAR[]> result;
+  bool success =
+      windows_util::GetLongPath(GetJavaWstring(env, path).c_str(), &result);
+  if (!success) {
+    MaybeReportLastError(
+        std::string("GetLongPathName(") + GetJavaUTFString(env, path) + ")",
+        env, error_msg_holder);
+    return JNI_FALSE;
+  }
+  env->SetObjectArrayElement(
+      result_holder, 0,
+      env->NewString(reinterpret_cast<const jchar*>(result.get()),
+                     wcslen(result.get())));
+  return JNI_TRUE;
+}