Bug 1721939 - ProfilerThreadRegistrationInfo - r=canaltinova

`ProfilerThreadRegistrationInfo` will replace `ThreadInfo`, and contains thread-specific information that may be kept after that thread has ended, to identify recorded profiling data about that thread.
It is public and not ref-counted because it will be included as value into the thread registration data (to avoid a separate allocation).

Differential Revision: https://phabricator.services.mozilla.com/D120813

tools/profiler/moz.build

@@ -154,6 +154,7 @@ EXPORTS.mozilla += [
     "public/ProfilerMarkersPrerequisites.h",
     "public/ProfilerMarkerTypes.h",
     "public/ProfilerState.h",
+    "public/ProfilerThreadRegistrationInfo.h",
     "public/ProfilerUtils.h",
 ]
 

tools/profiler/public/ProfilerThreadRegistrationInfo.h

@@ -0,0 +1,55 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ProfilerThreadRegistrationInfo_h
+#define ProfilerThreadRegistrationInfo_h
+
+#include "mozilla/ProfilerUtils.h"
+#include "mozilla/TimeStamp.h"
+
+#include <string>
+
+namespace mozilla::profiler {
+
+// This class contains immutable information about a thread which needs to be
+// stored across restarts of the profiler and which can be useful even after the
+// thread has stopped running.
+class ThreadRegistrationInfo {
+ public:
+  // Construct on the thread.
+  explicit ThreadRegistrationInfo(const char* aName) : mName(aName) {}
+
+  // Construct for a foreign thread (e.g., Java).
+  ThreadRegistrationInfo(const char* aName, ProfilerThreadId aThreadId,
+                         bool aIsMainThread, const TimeStamp& aRegisterTime)
+      : mName(aName),
+        mRegisterTime(aRegisterTime),
+        mThreadId(aThreadId),
+        mIsMainThread(aIsMainThread) {}
+
+  // Only allow move construction, for extraction when the thread ends.
+  ThreadRegistrationInfo(ThreadRegistrationInfo&&) = default;
+
+  // Other copies/moves disallowed.
+  ThreadRegistrationInfo(const ThreadRegistrationInfo&) = delete;
+  ThreadRegistrationInfo& operator=(const ThreadRegistrationInfo&) = delete;
+  ThreadRegistrationInfo& operator=(ThreadRegistrationInfo&&) = delete;
+
+  [[nodiscard]] const char* Name() const { return mName.c_str(); }
+  [[nodiscard]] const TimeStamp& RegisterTime() const { return mRegisterTime; }
+  [[nodiscard]] ProfilerThreadId ThreadId() const { return mThreadId; }
+  [[nodiscard]] bool IsMainThread() const { return mIsMainThread; }
+
+ private:
+  const std::string mName;
+  const TimeStamp mRegisterTime = TimeStamp::Now();
+  const ProfilerThreadId mThreadId = profiler_current_thread_id();
+  const bool mIsMainThread = profiler_is_main_thread();
+};
+
+}  // namespace mozilla::profiler
+
+#endif  // ProfilerThreadRegistrationInfo_h

tools/profiler/tests/gtest/GeckoProfiler.cpp

@@ -9,7 +9,9 @@
 // happens when calling these functions. They don't do much inspection of
 // profiler internals.
 
+#include "mozilla/ProfilerThreadRegistrationInfo.h"
 #include "mozilla/ProfilerUtils.h"
+#include "mozilla/UniquePtrExtensions.h"
 
 #include "gtest/gtest.h"
 
@@ -34,7 +36,6 @@
 #  include "mozilla/ProfileBufferEntrySerializationGeckoExtensions.h"
 #  include "mozilla/ProfileJSONWriter.h"
 #  include "mozilla/ScopeExit.h"
-#  include "mozilla/UniquePtrExtensions.h"
 #  include "mozilla/net/HttpBaseChannel.h"
 #  include "nsIChannelEventSink.h"
 #  include "nsIThread.h"
@@ -98,6 +99,72 @@ TEST(GeckoProfiler, ProfilerUtils)
   testThread.join();
 }
 
+TEST(GeckoProfiler, ThreadRegistrationInfo)
+{
+  profiler_init_main_thread_id();
+
+  TimeStamp ts = TimeStamp::Now();
+  {
+    profiler::ThreadRegistrationInfo trInfo{
+        "name", ProfilerThreadId::FromNumber(123), false, ts};
+    EXPECT_STREQ(trInfo.Name(), "name");
+    EXPECT_NE(trInfo.Name(), "name")
+        << "ThreadRegistrationInfo should keep its own copy of the name";
+    EXPECT_EQ(trInfo.RegisterTime(), ts);
+    EXPECT_EQ(trInfo.ThreadId(), ProfilerThreadId::FromNumber(123));
+    EXPECT_EQ(trInfo.IsMainThread(), false);
+  }
+
+  // Make sure the next timestamp will be different from `ts`.
+  while (TimeStamp::Now() == ts) {
+  }
+
+  {
+    profiler::ThreadRegistrationInfo trInfoHere{"Here"};
+    EXPECT_STREQ(trInfoHere.Name(), "Here");
+    EXPECT_NE(trInfoHere.Name(), "Here")
+        << "ThreadRegistrationInfo should keep its own copy of the name";
+    EXPECT_GT(trInfoHere.RegisterTime(), ts);
+    EXPECT_EQ(trInfoHere.ThreadId(), profiler_current_thread_id());
+    EXPECT_EQ(trInfoHere.ThreadId(), profiler_main_thread_id())
+        << "Gtests are assumed to run on the main thread";
+    EXPECT_EQ(trInfoHere.IsMainThread(), true)
+        << "Gtests are assumed to run on the main thread";
+  }
+
+  {
+    // Sub-thread test.
+    // These will receive sub-thread data (to test move at thread end).
+    TimeStamp tsThread;
+    ProfilerThreadId threadThreadId;
+    UniquePtr<profiler::ThreadRegistrationInfo> trInfoThreadPtr;
+
+    std::thread testThread([&]() {
+      profiler::ThreadRegistrationInfo trInfoThread{"Thread"};
+      EXPECT_STREQ(trInfoThread.Name(), "Thread");
+      EXPECT_NE(trInfoThread.Name(), "Thread")
+          << "ThreadRegistrationInfo should keep its own copy of the name";
+      EXPECT_GT(trInfoThread.RegisterTime(), ts);
+      EXPECT_EQ(trInfoThread.ThreadId(), profiler_current_thread_id());
+      EXPECT_NE(trInfoThread.ThreadId(), profiler_main_thread_id());
+      EXPECT_EQ(trInfoThread.IsMainThread(), false);
+
+      tsThread = trInfoThread.RegisterTime();
+      threadThreadId = trInfoThread.ThreadId();
+      trInfoThreadPtr =
+          MakeUnique<profiler::ThreadRegistrationInfo>(std::move(trInfoThread));
+    });
+    testThread.join();
+
+    ASSERT_NE(trInfoThreadPtr, nullptr);
+    EXPECT_STREQ(trInfoThreadPtr->Name(), "Thread");
+    EXPECT_EQ(trInfoThreadPtr->RegisterTime(), tsThread);
+    EXPECT_EQ(trInfoThreadPtr->ThreadId(), threadThreadId);
+    EXPECT_EQ(trInfoThreadPtr->IsMainThread(), false)
+        << "Gtests are assumed to run on the main thread";
+  }
+}
+
 #ifdef MOZ_GECKO_PROFILER
 
 TEST(BaseProfiler, BlocksRingBuffer)