// @file goodies.h
// miscellaneous

/*    Copyright 2009 10gen 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.
 */

#pragma once

#include "../bson/util/misc.h"
#include "concurrency/mutex.h"

namespace mongo {

    /* @return a dump of the buffer as hex byte ascii output */
    string hexdump(const char *data, unsigned len);

    /**
     * @return if this name has an increasing counter associated, return the value
     *         otherwise 0
     */
    unsigned setThreadName(const char * name);
    string getThreadName();

    template<class T>
    inline string ToString(const T& t) {
        stringstream s;
        s << t;
        return s.str();
    }

#if !defined(_WIN32) && !defined(NOEXECINFO) && !defined(__freebsd__) && !defined(__openbsd__) && !defined(__sun__)

} // namespace mongo

#include <pthread.h>
#include <execinfo.h>

namespace mongo {

    inline pthread_t GetCurrentThreadId() {
        return pthread_self();
    }

    /* use "addr2line -CFe <exe>" to parse. */
    inline void printStackTrace( ostream &o = cout ) {
        void *b[20];

        int size = backtrace(b, 20);
        for (int i = 0; i < size; i++)
            o << hex << b[i] << dec << ' ';
        o << endl;

        char **strings;

        strings = backtrace_symbols(b, size);
        for (int i = 0; i < size; i++)
            o << ' ' << strings[i] << '\n';
        o.flush();
        free (strings);
    }
#else
    inline void printStackTrace( ostream &o = cout ) { }
#endif

    bool isPrime(int n);
    int nextPrime(int n);

    inline void dumpmemory(const char *data, int len) {
        if ( len > 1024 )
            len = 1024;
        try {
            const char *q = data;
            const char *p = q;
            while ( len > 0 ) {
                for ( int i = 0; i < 16; i++ ) {
                    if ( *p >= 32 && *p <= 126 )
                        cout << *p;
                    else
                        cout << '.';
                    p++;
                }
                cout << "  ";
                p -= 16;
                for ( int i = 0; i < 16; i++ )
                    cout << (unsigned) ((unsigned char)*p++) << ' ';
                cout << endl;
                len -= 16;
            }
        }
        catch (...) {
        }
    }

// PRINT(2+2);  prints "2+2: 4"
#define MONGO_PRINT(x) cout << #x ": " << (x) << endl
#define PRINT MONGO_PRINT
// PRINTFL; prints file:line
#define MONGO_PRINTFL cout << __FILE__ ":" << __LINE__ << endl
#define PRINTFL MONGO_PRINTFL
#define MONGO_FLOG log() << __FILE__ ":" << __LINE__ << endl
#define FLOG MONGO_FLOG

#undef assert
#define assert MONGO_assert

    inline bool startsWith(const char *str, const char *prefix) {
        size_t l = strlen(prefix);
        if ( strlen(str) < l ) return false;
        return strncmp(str, prefix, l) == 0;
    }
    inline bool startsWith(string s, string p) { return startsWith(s.c_str(), p.c_str()); }

    inline bool endsWith(const char *p, const char *suffix) {
        size_t a = strlen(p);
        size_t b = strlen(suffix);
        if ( b > a ) return false;
        return strcmp(p + a - b, suffix) == 0;
    }

    inline unsigned long swapEndian(unsigned long x) {
        return
            ((x & 0xff) << 24) |
            ((x & 0xff00) << 8) |
            ((x & 0xff0000) >> 8) |
            ((x & 0xff000000) >> 24);
    }

#if defined(BOOST_LITTLE_ENDIAN)
    inline unsigned long fixEndian(unsigned long x) {
        return x;
    }
#else
    inline unsigned long fixEndian(unsigned long x) {
        return swapEndian(x);
    }
#endif

#if !defined(_WIN32)
    typedef int HANDLE;
    inline void strcpy_s(char *dst, unsigned len, const char *src) {
        assert( strlen(src) < len );
        strcpy(dst, src);
    }
#else
    typedef void *HANDLE;
#endif

    /* thread local "value" rather than a pointer
       good for things which have copy constructors (and the copy constructor is fast enough)
       e.g.
         ThreadLocalValue<int> myint;
    */
    template<class T>
    class ThreadLocalValue {
    public:
        ThreadLocalValue( T def = 0 ) : _default( def ) { }

        T get() const {
            T * val = _val.get();
            if ( val )
                return *val;
            return _default;
        }

        void set( const T& i ) {
            T *v = _val.get();
            if( v ) {
                *v = i;
                return;
            }
            v = new T(i);
            _val.reset( v );
        }

    private:
        boost::thread_specific_ptr<T> _val;
        const T _default;
    };

    class ProgressMeter : boost::noncopyable {
    public:
        ProgressMeter( unsigned long long total , int secondsBetween = 3 , int checkInterval = 100 ) {
            reset( total , secondsBetween , checkInterval );
        }

        ProgressMeter() {
            _active = 0;
        }

        // typically you do ProgressMeterHolder
        void reset( unsigned long long total , int secondsBetween = 3 , int checkInterval = 100 ) {
            _total = total;
            _secondsBetween = secondsBetween;
            _checkInterval = checkInterval;

            _done = 0;
            _hits = 0;
            _lastTime = (int)time(0);

            _active = 1;
        }

        void finished() {
            _active = 0;
        }

        bool isActive() {
            return _active;
        }

        /**
         * @param n how far along we are relative to the total # we set in CurOp::setMessage
         * @return if row was printed
         */
        bool hit( int n = 1 ) {
            if ( ! _active ) {
                cout << "warning: hit on in-active ProgressMeter" << endl;
                return false;
            }

            _done += n;
            _hits++;
            if ( _hits % _checkInterval )
                return false;

            int t = (int) time(0);
            if ( t - _lastTime < _secondsBetween )
                return false;

            if ( _total > 0 ) {
                int per = (int)( ( (double)_done * 100.0 ) / (double)_total );
                cout << "\t\t" << _done << "/" << _total << "\t" << per << "%" << endl;
            }
            _lastTime = t;
            return true;
        }

        void setTotalWhileRunning( unsigned long long total ) {
            _total = total;
        }

        unsigned long long done() const { return _done; }

        unsigned long long hits() const { return _hits; }

        unsigned long long total() const { return _total; } 

        string toString() const {
            if ( ! _active )
                return "";
            stringstream buf;
            buf << _done << "/" << _total << " " << (_done*100)/_total << "%";
            return buf.str();
        }

        bool operator==( const ProgressMeter& other ) const {
            return this == &other;
        }
    private:

        bool _active;

        unsigned long long _total;
        int _secondsBetween;
        int _checkInterval;

        unsigned long long _done;
        unsigned long long _hits;
        int _lastTime;
    };

    // e.g.: 
    // CurOp * op = cc().curop();
    // ProgressMeterHolder pm( op->setMessage( "index: (1/3) external sort" , d->stats.nrecords , 10 ) );
    // loop { pm.hit(); }
    class ProgressMeterHolder : boost::noncopyable {
    public:
        ProgressMeterHolder( ProgressMeter& pm )
            : _pm( pm ) {
        }

        ~ProgressMeterHolder() {
            _pm.finished();
        }

        ProgressMeter* operator->() {
            return &_pm;
        }

        bool hit( int n = 1 ) {
            return _pm.hit( n );
        }

        void finished() {
            _pm.finished();
        }

        bool operator==( const ProgressMeter& other ) {
            return _pm == other;
        }

    private:
        ProgressMeter& _pm;
    };

    class TicketHolder {
    public:
        TicketHolder( int num ) : _mutex("TicketHolder") {
            _outof = num;
            _num = num;
        }

        bool tryAcquire() {
            scoped_lock lk( _mutex );
            return _tryAcquire();
        }

        void waitForTicket() {
            scoped_lock lk( _mutex );

            while( ! _tryAcquire() ) {
                _newTicket.wait( lk.boost() );
            }
        }

        void release() {
            {
                scoped_lock lk( _mutex );
                _num++;
            }
            _newTicket.notify_one();
        }

        void resize( int newSize ) {
            {
                scoped_lock lk( _mutex );

                int used = _outof - _num;
                if ( used > newSize ) {
                    cout << "ERROR: can't resize since we're using (" << used << ") more than newSize(" << newSize << ")" << endl;
                    return;
                }

                _outof = newSize;
                _num = _outof - used;
            }

            // Potentially wasteful, but easier to see is correct
            _newTicket.notify_all();
        }

        int available() const {
            return _num;
        }

        int used() const {
            return _outof - _num;
        }

        int outof() const { return _outof; }

    private:

        bool _tryAcquire(){
            if ( _num <= 0 ) {
                if ( _num < 0 ) {
                    cerr << "DISASTER! in TicketHolder" << endl;
                }
                return false;
            }
            _num--;
            return true;
        }

        int _outof;
        int _num;
        mongo::mutex _mutex;
        boost::condition_variable_any _newTicket;
    };

    class TicketHolderReleaser {
    public:
        TicketHolderReleaser( TicketHolder * holder ) {
            _holder = holder;
        }

        ~TicketHolderReleaser() {
            _holder->release();
        }
    private:
        TicketHolder * _holder;
    };


    /**
     * this is a thread safe string
     * you will never get a bad pointer, though data may be mungedd
     */
    class ThreadSafeString {
    public:
        ThreadSafeString( size_t size=256 )
            : _size( size ) , _buf( new char[size] ) {
            memset( _buf , 0 , _size );
        }

        ThreadSafeString( const ThreadSafeString& other )
            : _size( other._size ) , _buf( new char[_size] ) {
            strncpy( _buf , other._buf , _size );
        }

        ~ThreadSafeString() {
            delete[] _buf;
            _buf = 0;
        }

        string toString() const {
            string s = _buf;
            return s;
        }

        ThreadSafeString& operator=( const char * str ) {
            size_t s = strlen(str);
            if ( s >= _size - 2 )
                s = _size - 2;
            strncpy( _buf , str , s );
            _buf[s] = 0;
            return *this;
        }

        bool operator==( const ThreadSafeString& other ) const {
            return strcmp( _buf , other._buf ) == 0;
        }

        bool operator==( const char * str ) const {
            return strcmp( _buf , str ) == 0;
        }

        bool operator!=( const char * str ) const {
            return strcmp( _buf , str ) != 0;
        }

        bool empty() const {
            return _buf == 0 || _buf[0] == 0;
        }

    private:
        size_t _size;
        char * _buf;
    };

    ostream& operator<<( ostream &s, const ThreadSafeString &o );

    /** A generic pointer type for function arguments.
     *  It will convert from any pointer type except auto_ptr.
     *  Semantics are the same as passing the pointer returned from get()
     *  const ptr<T>  =>  T * const
     *  ptr<const T>  =>  T const *  or  const T*
     */
    template <typename T>
    struct ptr {

        ptr() : _p(NULL) {}

        // convert to ptr<T>
        ptr(T* p) : _p(p) {} // needed for NULL
        template<typename U> ptr(U* p) : _p(p) {}
        template<typename U> ptr(const ptr<U>& p) : _p(p) {}
        template<typename U> ptr(const boost::shared_ptr<U>& p) : _p(p.get()) {}
        template<typename U> ptr(const boost::scoped_ptr<U>& p) : _p(p.get()) {}
        //template<typename U> ptr(const auto_ptr<U>& p) : _p(p.get()) {}

        // assign to ptr<T>
        ptr& operator= (T* p) { _p = p; return *this; } // needed for NULL
        template<typename U> ptr& operator= (U* p) { _p = p; return *this; }
        template<typename U> ptr& operator= (const ptr<U>& p) { _p = p; return *this; }
        template<typename U> ptr& operator= (const boost::shared_ptr<U>& p) { _p = p.get(); return *this; }
        template<typename U> ptr& operator= (const boost::scoped_ptr<U>& p) { _p = p.get(); return *this; }
        //template<typename U> ptr& operator= (const auto_ptr<U>& p) { _p = p.get(); return *this; }

        // use
        T* operator->() const { return _p; }
        T& operator*() const { return *_p; }

        // convert from ptr<T>
        operator T* () const { return _p; }

    private:
        T* _p;
    };



    /** Hmmmm */
    using namespace boost;

} // namespace mongo