// Licensed to the Apache Software Foundation (ASF) under one

// or more contributor license agreements.  See the NOTICE file

// distributed with this work for additional information

// regarding copyright ownership.  The ASF licenses this file

// to you 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.

// bthread - An M:N threading library to make applications more concurrent.

// Date: Tue Jul 10 17:40:58 CST 2012

#ifndef BTHREAD_TASK_META_H

#define BTHREAD_TASK_META_H

#include <pthread.h>                 // pthread_spin_init

#include "bthread/butex.h"           // butex_construct/destruct

#include "butil/atomicops.h"          // butil::atomic

#include "bthread/types.h"           // bthread_attr_t

#include "bthread/stack.h"           // ContextualStack

#include "bthread/timer_thread.h"

#include "butil/thread_local.h"

namespace bthread {

struct TaskStatistics {

    int64_t cputime_ns;

    int64_t nswitch;

    int64_t cpu_usage_ns;

};

class KeyTable;

struct ButexWaiter;

struct LocalStorage {

    KeyTable* keytable;

    void* assigned_data;

    void* rpcz_parent_span;  // Points to std::weak_ptr<brpc::Span>* (managed by brpc)

};

#define BTHREAD_LOCAL_STORAGE_INITIALIZER { NULL, NULL, NULL }

const static LocalStorage LOCAL_STORAGE_INIT = BTHREAD_LOCAL_STORAGE_INITIALIZER;

EXTERN_BAIDU_VOLATILE_THREAD_LOCAL(LocalStorage, tls_bls);

enum TaskStatus {

    TASK_STATUS_UNKNOWN,

    TASK_STATUS_CREATED,

    TASK_STATUS_FIRST_READY,

    TASK_STATUS_READY,

    TASK_STATUS_JUMPING,

    TASK_STATUS_RUNNING,

    TASK_STATUS_SUSPENDED,

    TASK_STATUS_END,

};

struct TaskMeta {

    // [Not Reset]

    butil::atomic<ButexWaiter*> current_waiter{NULL};

    uint64_t current_sleep{TimerThread::INVALID_TASK_ID};

    // A flag to mark if the Timer scheduling failed.

    bool sleep_failed{false};

    // A builtin flag to mark if the thread is stopping.

    bool stop{false};

    // The thread is interrupted and should wake up from some blocking ops.

    bool interrupted{false};

    // Scheduling of the thread can be delayed.

    bool about_to_quit{false};

    // [Not Reset] guarantee visibility of version_butex.

    pthread_spinlock_t version_lock{};

    // [Not Reset] only modified by one bthread at any time, no need to be atomic

    uint32_t* version_butex{NULL};

    // The identifier. It does not have to be here, however many code is

    // simplified if they can get tid from TaskMeta.

    bthread_t tid{INVALID_BTHREAD};

    // User function and argument

    void* (*fn)(void*){NULL};

    void* arg{NULL};

    // Stack of this task.

    ContextualStack* stack{NULL};

    // Attributes creating this task

    bthread_attr_t attr{BTHREAD_ATTR_NORMAL};

    // Statistics

    int64_t cpuwide_start_ns{0};

    TaskStatistics stat{};

    // bthread local storage, sync with tls_bls (defined in task_group.cpp)

    // when the bthread is created or destroyed.

    // DO NOT use this field directly, use tls_bls instead.

    LocalStorage local_storage{};

    // Only used when TaskTracer is enabled.

    // Bthread status.

    TaskStatus status{TASK_STATUS_UNKNOWN};

    // Whether bthread is traced？

    bool traced{false};

    // [Not Reset] guarantee tracing completion before jumping.

    pthread_mutex_t trace_lock{};

    // Worker thread id.

    pthread_t worker_tid{};

public:

    // Only initialize [Not Reset] fields, other fields will be reset in

    // bthread_start* functions

    TaskMeta() {

        pthread_spin_init(&version_lock, 0);

        version_butex = butex_create_checked<uint32_t>();

        *version_butex = 1;

        pthread_mutex_init(&trace_lock, NULL);

    }

    ~TaskMeta() {

        pthread_mutex_destroy(&trace_lock);

        butex_destroy(version_butex);

        version_butex = NULL;

        pthread_spin_destroy(&version_lock);

    }

    void set_stack(ContextualStack* s) {

        stack = s;

    }

    ContextualStack* release_stack() {

        ContextualStack* tmp = stack;

        stack = NULL;

        return tmp;

    }

    StackType stack_type() const {

        return static_cast<StackType>(attr.stack_type);

    }

};

// Global callback for creating a new bthread span when creating a new bthread.

// This is set by brpc layer. When a bthread is created with BTHREAD_INHERIT_SPAN,

// this callback is invoked to create a new span for the bthread.

// The returned void* points to a heap-allocated weak_ptr<Span>* managed by brpc layer.

// Returns NULL if span creation is disabled or fails.

extern void* (*g_create_bthread_span)();

// Global destructor callback for rpcz_parent_span.

// This is set by brpc layer to clean up the heap-allocated weak_ptr.

// bthread layer doesn't know the concrete type, it just calls this function

// with the void* pointer when cleaning up LocalStorage.

extern void (*g_rpcz_parent_span_dtor)(void*);

// Global callback invoked when a bthread ends (used by higher layers to

// observe and react to bthread end events, e.g., to finish spans). This

// pointer is set by the upper layer during initialization.

extern void (*g_end_bthread_span)();

}  // namespace bthread

#endif  // BTHREAD_TASK_META_H