//

// Copyright 2022 The Abseil Authors.

//

// 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

//

//      https://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 "absl/log/internal/log_sink_set.h"

#ifndef ABSL_HAVE_THREAD_LOCAL

#include <pthread.h>

#endif

#ifdef __ANDROID__

#include <android/log.h>

#endif

#ifdef _WIN32

#include <windows.h>

#endif

#include <algorithm>

#include <vector>

#include "absl/base/attributes.h"

#include "absl/base/call_once.h"

#include "absl/base/config.h"

#include "absl/base/internal/raw_logging.h"

#include "absl/base/log_severity.h"

#include "absl/base/no_destructor.h"

#include "absl/base/thread_annotations.h"

#include "absl/cleanup/cleanup.h"

#include "absl/log/globals.h"

#include "absl/log/internal/config.h"

#include "absl/log/internal/globals.h"

#include "absl/log/log_entry.h"

#include "absl/log/log_sink.h"

#include "absl/strings/string_view.h"

#include "absl/synchronization/mutex.h"

#include "absl/types/span.h"

namespace absl {

ABSL_NAMESPACE_BEGIN

namespace log_internal {

namespace {

// Returns a mutable reference to a thread-local variable that should be true if

// a globally-registered `LogSink`'s `Send()` is currently being invoked on this

// thread.

bool& ThreadIsLoggingStatus() {

#ifdef ABSL_HAVE_THREAD_LOCAL

  ABSL_CONST_INIT thread_local bool thread_is_logging = false;

  return thread_is_logging;

#else

  ABSL_CONST_INIT static pthread_key_t thread_is_logging_key;

  static const bool unused = [] {

    if (pthread_key_create(&thread_is_logging_key, [](void* data) {

          delete reinterpret_cast<bool*>(data);

        })) {

      perror("pthread_key_create failed!");

      abort();

    }

    return true;

  }();

  (void)unused;  // Fixes -wunused-variable warning

  bool* thread_is_logging_ptr =

      reinterpret_cast<bool*>(pthread_getspecific(thread_is_logging_key));

  if (ABSL_PREDICT_FALSE(!thread_is_logging_ptr)) {

    thread_is_logging_ptr = new bool{false};

    if (pthread_setspecific(thread_is_logging_key, thread_is_logging_ptr)) {

      perror("pthread_setspecific failed");

      abort();

    }

  }

  return *thread_is_logging_ptr;

#endif

}

class StderrLogSink final : public LogSink {

 public:

  ~StderrLogSink() override = default;

  void Send(const absl::LogEntry& entry) override {

    if (entry.log_severity() < absl::StderrThreshold() &&

        absl::log_internal::IsInitialized()) {

      return;

    }

    ABSL_CONST_INIT static absl::once_flag warn_if_not_initialized;

    absl::call_once(warn_if_not_initialized, []() {

      if (absl::log_internal::IsInitialized()) return;

      const char w[] =

          "WARNING: All log messages before absl::InitializeLog() is called"

          " are written to STDERR\n";

      absl::log_internal::WriteToStderr(w, absl::LogSeverity::kWarning);

    });

    if (!entry.stacktrace().empty()) {

      absl::log_internal::WriteToStderr(entry.stacktrace(),

                                        entry.log_severity());

    } else {

      // TODO(b/226937039): do this outside else condition once we avoid

      // ReprintFatalMessage

      absl::log_internal::WriteToStderr(

          entry.text_message_with_prefix_and_newline(), entry.log_severity());

    }

  }

};

#if defined(__ANDROID__)

class AndroidLogSink final : public LogSink {

 public:

  ~AndroidLogSink() override = default;

  void Send(const absl::LogEntry& entry) override {

    const int level = AndroidLogLevel(entry);

    const char* const tag = GetAndroidNativeTag();

    __android_log_write(level, tag,

                        entry.text_message_with_prefix_and_newline_c_str());

    if (entry.log_severity() == absl::LogSeverity::kFatal)

      __android_log_write(ANDROID_LOG_FATAL, tag, "terminating.\n");

  }

 private:

  static int AndroidLogLevel(const absl::LogEntry& entry) {

    switch (entry.log_severity()) {

      case absl::LogSeverity::kFatal:

        return ANDROID_LOG_FATAL;

      case absl::LogSeverity::kError:

        return ANDROID_LOG_ERROR;

      case absl::LogSeverity::kWarning:

        return ANDROID_LOG_WARN;

      default:

        if (entry.verbosity() >= 2) return ANDROID_LOG_VERBOSE;

        if (entry.verbosity() == 1) return ANDROID_LOG_DEBUG;

        return ANDROID_LOG_INFO;

    }

  }

};

#endif  // !defined(__ANDROID__)

#if defined(_WIN32)

class WindowsDebuggerLogSink final : public LogSink {

 public:

  ~WindowsDebuggerLogSink() override = default;

  void Send(const absl::LogEntry& entry) override {

    if (entry.log_severity() < absl::StderrThreshold() &&

        absl::log_internal::IsInitialized()) {

      return;

    }

    ::OutputDebugStringA(entry.text_message_with_prefix_and_newline_c_str());

  }

};

#endif  // !defined(_WIN32)

class GlobalLogSinkSet final {

 public:

  GlobalLogSinkSet() {

#if defined(__myriad2__) || defined(__Fuchsia__)

    // myriad2 and Fuchsia do not log to stderr by default.

#else

    static absl::NoDestructor<StderrLogSink> stderr_log_sink;

    AddLogSink(stderr_log_sink.get());

#endif

#ifdef __ANDROID__

    static absl::NoDestructor<AndroidLogSink> android_log_sink;

    AddLogSink(android_log_sink.get());

#endif

#if defined(_WIN32)

    static absl::NoDestructor<WindowsDebuggerLogSink> debugger_log_sink;

    AddLogSink(debugger_log_sink.get());

#endif  // !defined(_WIN32)

  }

  void LogToSinks(const absl::LogEntry& entry,

                  absl::Span<absl::LogSink*> extra_sinks, bool extra_sinks_only)

      ABSL_LOCKS_EXCLUDED(guard_) {

    SendToSinks(entry, extra_sinks);

    if (!extra_sinks_only) {

      if (ThreadIsLoggingToLogSink()) {

        absl::log_internal::WriteToStderr(

            entry.text_message_with_prefix_and_newline(), entry.log_severity());

      } else {

        absl::ReaderMutexLock global_sinks_lock(&guard_);

        ThreadIsLoggingStatus() = true;

        // Ensure the "thread is logging" status is reverted upon leaving the

        // scope even in case of exceptions.

        auto status_cleanup =

            absl::MakeCleanup([] { ThreadIsLoggingStatus() = false; });

        SendToSinks(entry, absl::MakeSpan(sinks_));

      }

    }

  }

  void AddLogSink(absl::LogSink* sink) ABSL_LOCKS_EXCLUDED(guard_) {

    {

      absl::WriterMutexLock global_sinks_lock(&guard_);

      auto pos = std::find(sinks_.begin(), sinks_.end(), sink);

      if (pos == sinks_.end()) {

        sinks_.push_back(sink);

        return;

      }

    }

    ABSL_INTERNAL_LOG(FATAL, "Duplicate log sinks are not supported");

  }

  void RemoveLogSink(absl::LogSink* sink) ABSL_LOCKS_EXCLUDED(guard_) {

    {

      absl::WriterMutexLock global_sinks_lock(&guard_);

      auto pos = std::find(sinks_.begin(), sinks_.end(), sink);

      if (pos != sinks_.end()) {

        sinks_.erase(pos);

        return;

      }

    }

    ABSL_INTERNAL_LOG(FATAL, "Mismatched log sink being removed");

  }

  void FlushLogSinks() ABSL_LOCKS_EXCLUDED(guard_) {

    if (ThreadIsLoggingToLogSink()) {

      // The thread_local condition demonstrates that we're already holding the

      // lock in order to iterate over `sinks_` for dispatch.  The thread-safety

      // annotations don't know this, so we use `ABSL_NO_THREAD_SAFETY_ANALYSIS`

      guard_.AssertReaderHeld();

      FlushLogSinksLocked();

    } else {

      absl::ReaderMutexLock global_sinks_lock(&guard_);

      // In case if LogSink::Flush overload decides to log

      ThreadIsLoggingStatus() = true;

      // Ensure the "thread is logging" status is reverted upon leaving the

      // scope even in case of exceptions.

      auto status_cleanup =

          absl::MakeCleanup([] { ThreadIsLoggingStatus() = false; });

      FlushLogSinksLocked();

    }

  }

 private:

  void FlushLogSinksLocked() ABSL_SHARED_LOCKS_REQUIRED(guard_) {

    for (absl::LogSink* sink : sinks_) {

      sink->Flush();

    }

  }

  // Helper routine for LogToSinks.

  static void SendToSinks(const absl::LogEntry& entry,

                          absl::Span<absl::LogSink*> sinks) {

    for (absl::LogSink* sink : sinks) {

      sink->Send(entry);

    }

  }

  using LogSinksSet = std::vector<absl::LogSink*>;

  absl::Mutex guard_;

  LogSinksSet sinks_ ABSL_GUARDED_BY(guard_);

};

// Returns reference to the global LogSinks set.

GlobalLogSinkSet& GlobalSinks() {

  static absl::NoDestructor<GlobalLogSinkSet> global_sinks;

  return *global_sinks;

}

}  // namespace

bool ThreadIsLoggingToLogSink() { return ThreadIsLoggingStatus(); }

void LogToSinks(const absl::LogEntry& entry,

                absl::Span<absl::LogSink*> extra_sinks, bool extra_sinks_only) {

  log_internal::GlobalSinks().LogToSinks(entry, extra_sinks, extra_sinks_only);

}

void AddLogSink(absl::LogSink* sink) {

  log_internal::GlobalSinks().AddLogSink(sink);

}

void RemoveLogSink(absl::LogSink* sink) {

  log_internal::GlobalSinks().RemoveLogSink(sink);

}

void FlushLogSinks() { log_internal::GlobalSinks().FlushLogSinks(); }

}  // namespace log_internal

ABSL_NAMESPACE_END

}  // namespace absl