move MemoryMapping, Shell, ThreadId, ThreadName, and VersionCheck to system/

[folly.git] / folly / system / ThreadName.cpp

diff --git a/folly/system/ThreadName.cpp b/folly/system/ThreadName.cpp
new file mode 100644 (file)
index 0000000..49793a9
--- /dev/null
+++ b/folly/system/ThreadName.cpp
@@ -0,0 +1,151 @@
+/*
+ * Copyright 2017 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * 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.
+ */
+
+#include <folly/system/ThreadName.h>
+
+#include <type_traits>
+
+#include <folly/Portability.h>
+#include <folly/Traits.h>
+#include <folly/portability/PThread.h>
+
+namespace folly {
+
+// This looks a bit weird, but it's necessary to avoid
+// having an undefined compiler function called.
+#if defined(__GLIBC__) && !defined(__APPLE__) && !defined(__ANDROID__)
+#if __GLIBC_PREREQ(2, 12)
+// has pthread_setname_np(pthread_t, const char*) (2 params)
+#define FOLLY_HAS_PTHREAD_SETNAME_NP_THREAD_NAME 1
+#endif
+#endif
+
+#if defined(__APPLE__) && defined(__MAC_OS_X_VERSION_MIN_REQUIRED)
+#if __MAC_OS_X_VERSION_MIN_REQUIRED >= 1060
+// has pthread_setname_np(const char*) (1 param)
+#define FOLLY_HAS_PTHREAD_SETNAME_NP_NAME 1
+#endif
+#endif
+
+namespace {
+
+#if FOLLY_HAVE_PTHREAD && !_WIN32
+pthread_t stdTidToPthreadId(std::thread::id tid) {
+  static_assert(
+      std::is_same<pthread_t, std::thread::native_handle_type>::value,
+      "This assumes that the native handle type is pthread_t");
+  static_assert(
+      sizeof(std::thread::native_handle_type) == sizeof(std::thread::id),
+      "This assumes std::thread::id is a thin wrapper around "
+      "std::thread::native_handle_type, but that doesn't appear to be true.");
+  // In most implementations, std::thread::id is a thin wrapper around
+  // std::thread::native_handle_type, which means we can do unsafe things to
+  // extract it.
+  pthread_t id;
+  std::memcpy(&id, &tid, sizeof(id));
+  return id;
+}
+#endif
+
+} // namespace
+
+bool canSetCurrentThreadName() {
+#if FOLLY_HAS_PTHREAD_SETNAME_NP_THREAD_NAME || \
+    FOLLY_HAS_PTHREAD_SETNAME_NP_NAME
+  return true;
+#else
+  return false;
+#endif
+}
+
+bool canSetOtherThreadName() {
+#if FOLLY_HAS_PTHREAD_SETNAME_NP_THREAD_NAME
+  return true;
+#else
+  return false;
+#endif
+}
+
+static constexpr size_t kMaxThreadNameLength = 16;
+
+Optional<std::string> getThreadName(std::thread::id id) {
+#if FOLLY_HAS_PTHREAD_SETNAME_NP_THREAD_NAME || \
+    FOLLY_HAS_PTHREAD_SETNAME_NP_NAME
+  std::array<char, kMaxThreadNameLength> buf;
+  if (pthread_getname_np(stdTidToPthreadId(id), buf.data(), buf.size()) != 0) {
+    return Optional<std::string>();
+  }
+  return make_optional(std::string(buf.data()));
+#else
+  return Optional<std::string>();
+#endif
+}
+
+Optional<std::string> getCurrentThreadName() {
+  return getThreadName(std::this_thread::get_id());
+}
+
+bool setThreadName(std::thread::id tid, StringPiece name) {
+#if !FOLLY_HAVE_PTHREAD || _WIN32
+  return false;
+#else
+  name = name.subpiece(0, kMaxThreadNameLength - 1);
+  char buf[kMaxThreadNameLength] = {};
+  std::memcpy(buf, name.data(), name.size());
+  auto id = stdTidToPthreadId(tid);
+#if FOLLY_HAS_PTHREAD_SETNAME_NP_THREAD_NAME
+  return 0 == pthread_setname_np(id, buf);
+#elif FOLLY_HAS_PTHREAD_SETNAME_NP_NAME
+  // Since OS X 10.6 it is possible for a thread to set its own name,
+  // but not that of some other thread.
+  if (pthread_equal(pthread_self(), id)) {
+    return 0 == pthread_setname_np(buf);
+  }
+  return false;
+#else
+  (void)id;
+  return false;
+#endif
+#endif
+}
+
+#if FOLLY_HAVE_PTHREAD
+bool setThreadName(pthread_t pid, StringPiece name) {
+#if _WIN32
+  // Not currently supported on Windows.
+  return false;
+#else
+  static_assert(
+      std::is_same<pthread_t, std::thread::native_handle_type>::value,
+      "This assumes that the native handle type is pthread_t");
+  static_assert(
+      sizeof(std::thread::native_handle_type) == sizeof(std::thread::id),
+      "This assumes std::thread::id is a thin wrapper around "
+      "std::thread::native_handle_type, but that doesn't appear to be true.");
+  // In most implementations, std::thread::id is a thin wrapper around
+  // std::thread::native_handle_type, which means we can do unsafe things to
+  // extract it.
+  std::thread::id id;
+  std::memcpy(&id, &pid, sizeof(id));
+  return setThreadName(id, name);
+#endif
+}
+#endif
+
+bool setThreadName(StringPiece name) {
+  return setThreadName(std::this_thread::get_id(), name);
+}
+}