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Eagerly initialize JNI copies of Java classes: doing lazy initializat…
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…ion on a per-method basis doesn't save anything and adds a tiny bit of overhead to every one of these calls.

PiperOrigin-RevId: 380833502
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@janakdr @copybara-github
janakdr authored and copybara-github committed Jun 22, 2021
1 parent 2640745 commit 2579c9a
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Showing 2 changed files with 77 additions and 74 deletions.
31 changes: 16 additions & 15 deletions src/main/java/com/google/devtools/build/lib/unix/NativePosixFiles.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -27,29 +27,28 @@
* by the java.io package where appropriate--see package javadoc for details.
*/
public final class NativePosixFiles {

private NativePosixFiles() {}

static {
if (!java.nio.charset.Charset.defaultCharset().name().equals("ISO-8859-1")) {
// Defer the Logger call, so we don't deadlock if this is called from Logger
// initialization code.
new Thread() {
@Override
public void run() {
// wait (if necessary) until the logging system is initialized
synchronized (LogManager.getLogManager()) {
}
GoogleLogger.forEnclosingClass()
.atFine()
.log(
"WARNING: Default character set is not latin1; java.io.File and "
+ "com.google.devtools.build.lib.unix.FilesystemUtils will represent some "
+ "filenames differently.");
}
}.start();
new Thread(
() -> {
// wait (if necessary) until the logging system is initialized
synchronized (LogManager.getLogManager()) {
}
@SuppressWarnings("FloggerRequiredModifiers")
GoogleLogger logger = GoogleLogger.forEnclosingClass();
logger.atFine().log(
"WARNING: Default character set is not latin1; java.io.File and"
+ " com.google.devtools.build.lib.unix.FilesystemUtils will represent"
+ " some filenames differently.");
})
.start();
}
JniLoader.loadJni();
initJNIClasses();
}

/**
Expand Down Expand Up @@ -375,4 +374,6 @@ public static native byte[] lgetxattr(String path, String name)
* reference alive.
*/
public static native int close(int fd, Object ignored) throws IOException;

private static native void initJNIClasses();
}
120 changes: 61 additions & 59 deletions src/main/native/unix_jni.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -217,63 +217,52 @@ Java_com_google_devtools_build_lib_unix_NativePosixFiles_symlink(JNIEnv *env,
link_common(env, oldpath, newpath, ::symlink);
}

static jobject NewFileStatus(JNIEnv *env,
const portable_stat_struct &stat_ref) {
static jclass file_status_class = nullptr;
if (file_status_class == nullptr) { // note: harmless race condition
jclass local =
env->FindClass("com/google/devtools/build/lib/unix/FileStatus");
CHECK(local != nullptr);
file_status_class = static_cast<jclass>(env->NewGlobalRef(local));
}
namespace {
static jclass file_status_class = nullptr;
static jclass errno_file_status_class = nullptr;
static jmethodID file_status_class_ctor = nullptr;
static jmethodID errno_file_status_class_no_error_ctor = nullptr;
static jmethodID errno_file_status_class_errorno_ctor = nullptr;
static jclass dirents_class = nullptr;
static jmethodID dirents_ctor = nullptr;

static jclass makeStaticClass(JNIEnv *env, const char *name) {
jclass lookup_result = env->FindClass(name);
CHECK(lookup_result != nullptr);
return static_cast<jclass>(env->NewGlobalRef(lookup_result));
}

static jmethodID method = nullptr;
if (method == nullptr) { // note: harmless race condition
method = env->GetMethodID(file_status_class, "<init>", "(IIIIIIIJIJ)V");
CHECK(method != nullptr);
}
static jmethodID getConstructorID(JNIEnv *env, jclass clazz,
const char *parameters) {
jmethodID method = env->GetMethodID(clazz, "<init>", parameters);
CHECK(method != nullptr);
return method;
}

static jobject NewFileStatus(JNIEnv *env,
const portable_stat_struct &stat_ref) {
return env->NewObject(
file_status_class, method, stat_ref.st_mode,
file_status_class, file_status_class_ctor, stat_ref.st_mode,
StatSeconds(stat_ref, STAT_ATIME), StatNanoSeconds(stat_ref, STAT_ATIME),
StatSeconds(stat_ref, STAT_MTIME), StatNanoSeconds(stat_ref, STAT_MTIME),
StatSeconds(stat_ref, STAT_CTIME), StatNanoSeconds(stat_ref, STAT_CTIME),
static_cast<jlong>(stat_ref.st_size),
static_cast<int>(stat_ref.st_dev), static_cast<jlong>(stat_ref.st_ino));
static_cast<jlong>(stat_ref.st_size), static_cast<int>(stat_ref.st_dev),
static_cast<jlong>(stat_ref.st_ino));
}

static jobject NewErrnoFileStatus(JNIEnv *env,
int saved_errno,
const portable_stat_struct &stat_ref) {
static jclass errno_file_status_class = nullptr;
if (errno_file_status_class == nullptr) { // note: harmless race condition
jclass local =
env->FindClass("com/google/devtools/build/lib/unix/ErrnoFileStatus");
CHECK(local != nullptr);
errno_file_status_class = static_cast<jclass>(env->NewGlobalRef(local));
}

static jmethodID no_error_ctor = nullptr;
if (no_error_ctor == nullptr) { // note: harmless race condition
no_error_ctor = env->GetMethodID(errno_file_status_class,
"<init>", "(IIIIIIIJIJ)V");
CHECK(no_error_ctor != nullptr);
}

static jmethodID errorno_ctor = nullptr;
if (errorno_ctor == nullptr) { // note: harmless race condition
errorno_ctor = env->GetMethodID(errno_file_status_class, "<init>", "(I)V");
CHECK(errorno_ctor != nullptr);
}

if (saved_errno != 0) {
return env->NewObject(errno_file_status_class, errorno_ctor, saved_errno);
return env->NewObject(errno_file_status_class,
errno_file_status_class_errorno_ctor, saved_errno);
}
return env->NewObject(
errno_file_status_class, no_error_ctor, stat_ref.st_mode,
StatSeconds(stat_ref, STAT_ATIME), StatNanoSeconds(stat_ref, STAT_ATIME),
StatSeconds(stat_ref, STAT_MTIME), StatNanoSeconds(stat_ref, STAT_MTIME),
StatSeconds(stat_ref, STAT_CTIME), StatNanoSeconds(stat_ref, STAT_CTIME),
errno_file_status_class, errno_file_status_class_no_error_ctor,
stat_ref.st_mode, StatSeconds(stat_ref, STAT_ATIME),
StatNanoSeconds(stat_ref, STAT_ATIME), StatSeconds(stat_ref, STAT_MTIME),
StatNanoSeconds(stat_ref, STAT_MTIME), StatSeconds(stat_ref, STAT_CTIME),
StatNanoSeconds(stat_ref, STAT_CTIME),
static_cast<jlong>(stat_ref.st_size), static_cast<int>(stat_ref.st_dev),
static_cast<jlong>(stat_ref.st_ino));
}
Expand All @@ -287,6 +276,26 @@ static void SetIntField(JNIEnv *env,
CHECK(fid != nullptr);
env->SetIntField(object, fid, val);
}
} // namespace

extern "C" JNIEXPORT void JNICALL
Java_com_google_devtools_build_lib_unix_NativePosixFiles_initJNIClasses(
JNIEnv *env, jclass clazz) {
file_status_class =
makeStaticClass(env, "com/google/devtools/build/lib/unix/FileStatus");
errno_file_status_class = makeStaticClass(
env, "com/google/devtools/build/lib/unix/ErrnoFileStatus");
file_status_class_ctor =
getConstructorID(env, file_status_class, "(IIIIIIIJIJ)V");
errno_file_status_class_no_error_ctor =
getConstructorID(env, errno_file_status_class, "(IIIIIIIJIJ)V");
errno_file_status_class_errorno_ctor =
getConstructorID(env, errno_file_status_class, "(I)V");
dirents_class = makeStaticClass(
env, "com/google/devtools/build/lib/unix/NativePosixFiles$Dirents");
dirents_ctor =
getConstructorID(env, dirents_class, "([Ljava/lang/String;[B)V");
}

extern "C" JNIEXPORT void JNICALL
Java_com_google_devtools_build_lib_unix_ErrnoFileStatus_00024ErrnoConstants_initErrnoConstants( // NOLINT
Expand All @@ -299,6 +308,7 @@ Java_com_google_devtools_build_lib_unix_ErrnoFileStatus_00024ErrnoConstants_init
SetIntField(env, clazz, errno_constants, "ENAMETOOLONG", ENAMETOOLONG);
}

namespace {
static jobject StatCommon(JNIEnv *env, jstring path,
int (*stat_function)(const char *,
portable_stat_struct *),
Expand Down Expand Up @@ -331,6 +341,7 @@ static jobject StatCommon(JNIEnv *env, jstring path,
? NewFileStatus(env, statbuf)
: NewErrnoFileStatus(env, saved_errno, statbuf);
}
} // namespace

/*
* Class: com.google.devtools.build.lib.unix.NativePosixFiles
Expand Down Expand Up @@ -536,25 +547,11 @@ Java_com_google_devtools_build_lib_unix_NativePosixFiles_mkdirs(JNIEnv *env,
ReleaseStringLatin1Chars(path_chars);
}

namespace {
static jobject NewDirents(JNIEnv *env,
jobjectArray names,
jbyteArray types) {
// See http://java.sun.com/docs/books/jni/html/fldmeth.html#26855
static jclass dirents_class = nullptr;
if (dirents_class == nullptr) { // note: harmless race condition
jclass local = env->FindClass("com/google/devtools/build/lib/unix/NativePosixFiles$Dirents");
CHECK(local != nullptr);
dirents_class = static_cast<jclass>(env->NewGlobalRef(local));
}

static jmethodID ctor = nullptr;
if (ctor == nullptr) { // note: harmless race condition
ctor =
env->GetMethodID(dirents_class, "<init>", "([Ljava/lang/String;[B)V");
CHECK(ctor != nullptr);
}

return env->NewObject(dirents_class, ctor, names, types);
return env->NewObject(dirents_class, dirents_ctor, names, types);
}

static char GetDirentType(struct dirent *entry,
Expand Down Expand Up @@ -582,6 +579,7 @@ static char GetDirentType(struct dirent *entry,
return '?';
}
}
} // namespace

/*
* Class: com.google.devtools.build.lib.unix.NativePosixFiles
Expand Down Expand Up @@ -739,6 +737,7 @@ Java_com_google_devtools_build_lib_unix_NativePosixFiles_mkfifo(JNIEnv *env,
ReleaseStringLatin1Chars(path_chars);
}

namespace {
// Posts an exception generated by the DeleteTreesBelow algorithm and its helper
// functions.
//
Expand Down Expand Up @@ -973,6 +972,7 @@ static int DeleteTreesBelow(JNIEnv* env, std::vector<std::string>* dir_path,
dir_path->pop_back();
return env->ExceptionOccurred() == nullptr ? 0 : -1;
}
} // namespace

/*
* Class: com.google.devtools.build.lib.unix.NativePosixFiles
Expand All @@ -995,6 +995,7 @@ Java_com_google_devtools_build_lib_unix_NativePosixFiles_deleteTreesBelow(
////////////////////////////////////////////////////////////////////////
// Linux extended file attributes

namespace {
typedef ssize_t getxattr_func(const char *path, const char *name,
void *value, size_t size, bool *attr_not_found);

Expand Down Expand Up @@ -1027,6 +1028,7 @@ static jbyteArray getxattr_common(JNIEnv *env,
ReleaseStringLatin1Chars(name_chars);
return result;
}
} // namespace

extern "C" JNIEXPORT jbyteArray JNICALL
Java_com_google_devtools_build_lib_unix_NativePosixFiles_getxattr(JNIEnv *env,
Expand Down

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