pipeline.h

/*
    Copyright 2005-2016 Intel Corporation.  All Rights Reserved.

    This file is part of Threading Building Blocks. Threading Building Blocks is free software;
    you can redistribute it and/or modify it under the terms of the GNU General Public License
    version 2  as  published  by  the  Free Software Foundation.  Threading Building Blocks is
    distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the
    implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
    See  the GNU General Public License for more details.   You should have received a copy of
    the  GNU General Public License along with Threading Building Blocks; if not, write to the
    Free Software Foundation, Inc.,  51 Franklin St,  Fifth Floor,  Boston,  MA 02110-1301 USA

    As a special exception,  you may use this file  as part of a free software library without
    restriction.  Specifically,  if other files instantiate templates  or use macros or inline
    functions from this file, or you compile this file and link it with other files to produce
    an executable,  this file does not by itself cause the resulting executable to be covered
    by the GNU General Public License. This exception does not however invalidate any other
    reasons why the executable file might be covered by the GNU General Public License.
*/

#ifndef __TBB_pipeline_H
#define __TBB_pipeline_H

#include "atomic.h"
#include "task.h"
#include "tbb_allocator.h"
#include <cstddef>

#if __TBB_CPP11_TYPE_PROPERTIES_PRESENT || __TBB_TR1_TYPE_PROPERTIES_IN_STD_PRESENT
#include <type_traits>
#endif

namespace tbb {

class pipeline;
class filter;

namespace internal {

// The argument for PIPELINE_VERSION should be an integer between 2 and 9
#define __TBB_PIPELINE_VERSION(x) ((unsigned char)(x-2)<<1)

typedef unsigned long Token;
typedef long tokendiff_t;
class stage_task;
class input_buffer;
class pipeline_root_task;
class pipeline_cleaner;

} // namespace internal

namespace interface6 {
    template<typename T, typename U> class filter_t;

    namespace internal {
        class pipeline_proxy;
    }
}



class filter: internal::no_copy {
private:
    static filter* not_in_pipeline() {return reinterpret_cast<filter*>(intptr_t(-1));}
protected:
    static const unsigned char filter_is_serial = 0x1;


    static const unsigned char filter_is_out_of_order = 0x1<<4;

    static const unsigned char filter_is_bound = 0x1<<5;

    static const unsigned char filter_may_emit_null = 0x1<<6;

    static const unsigned char exact_exception_propagation =
#if TBB_USE_CAPTURED_EXCEPTION
            0x0;
#else
            0x1<<7;
#endif /* TBB_USE_CAPTURED_EXCEPTION */

    static const unsigned char current_version = __TBB_PIPELINE_VERSION(5);
    static const unsigned char version_mask = 0x7<<1; // bits 1-3 are for version
public:
    enum mode {
        parallel = current_version | filter_is_out_of_order,
        serial_in_order = current_version | filter_is_serial,
        serial_out_of_order = current_version | filter_is_serial | filter_is_out_of_order,
        serial = serial_in_order
    };
protected:
    filter( bool is_serial_ ) :
        next_filter_in_pipeline(not_in_pipeline()),
        my_input_buffer(NULL),
        my_filter_mode(static_cast<unsigned char>((is_serial_ ? serial : parallel) | exact_exception_propagation)),
        prev_filter_in_pipeline(not_in_pipeline()),
        my_pipeline(NULL),
        next_segment(NULL)
    {}

    filter( mode filter_mode ) :
        next_filter_in_pipeline(not_in_pipeline()),
        my_input_buffer(NULL),
        my_filter_mode(static_cast<unsigned char>(filter_mode | exact_exception_propagation)),
        prev_filter_in_pipeline(not_in_pipeline()),
        my_pipeline(NULL),
        next_segment(NULL)
    {}

    // signal end-of-input for concrete_filters
    void __TBB_EXPORTED_METHOD set_end_of_input();

public:
    bool is_serial() const {
        return bool( my_filter_mode & filter_is_serial );
    }

    bool is_ordered() const {
        return (my_filter_mode & (filter_is_out_of_order|filter_is_serial))==filter_is_serial;
    }

    bool is_bound() const {
        return ( my_filter_mode & filter_is_bound )==filter_is_bound;
    }

    bool object_may_be_null() {
        return ( my_filter_mode & filter_may_emit_null ) == filter_may_emit_null;
    }


    virtual void* operator()( void* item ) = 0;


    virtual __TBB_EXPORTED_METHOD ~filter();

#if __TBB_TASK_GROUP_CONTEXT

    virtual void finalize( void* /*item*/ ) {};
#endif

private:
    filter* next_filter_in_pipeline;

    //  (pipeline has not yet reached end_of_input or this filter has not yet
    //  seen the last token produced by input_filter)
    bool has_more_work();


    internal::input_buffer* my_input_buffer;

    friend class internal::stage_task;
    friend class internal::pipeline_root_task;
    friend class pipeline;
    friend class thread_bound_filter;

    const unsigned char my_filter_mode;

    filter* prev_filter_in_pipeline;

    pipeline* my_pipeline;


    filter* next_segment;
};


class thread_bound_filter: public filter {
public:
    enum result_type {
        // item was processed
        success,
        // item is currently not available
        item_not_available,
        // there are no more items to process
        end_of_stream
    };
protected:
    thread_bound_filter(mode filter_mode):
         filter(static_cast<mode>(filter_mode | filter::filter_is_bound))
    {
        __TBB_ASSERT(filter_mode & filter::filter_is_serial, "thread-bound filters must be serial");
    }
public:

    result_type __TBB_EXPORTED_METHOD try_process_item();


    result_type __TBB_EXPORTED_METHOD process_item();

private:
    result_type internal_process_item(bool is_blocking);
};


class pipeline {
public:
    __TBB_EXPORTED_METHOD pipeline();

    virtual __TBB_EXPORTED_METHOD ~pipeline();

    void __TBB_EXPORTED_METHOD add_filter( filter& filter_ );

    void __TBB_EXPORTED_METHOD run( size_t max_number_of_live_tokens );

#if __TBB_TASK_GROUP_CONTEXT
    void __TBB_EXPORTED_METHOD run( size_t max_number_of_live_tokens, tbb::task_group_context& context );
#endif

    void __TBB_EXPORTED_METHOD clear();

private:
    friend class internal::stage_task;
    friend class internal::pipeline_root_task;
    friend class filter;
    friend class thread_bound_filter;
    friend class internal::pipeline_cleaner;
    friend class tbb::interface6::internal::pipeline_proxy;

    filter* filter_list;

    filter* filter_end;

    task* end_counter;

    atomic<internal::Token> input_tokens;

    atomic<internal::Token> token_counter;

    bool end_of_input;

    bool has_thread_bound_filters;

    void remove_filter( filter& filter_ );

    void __TBB_EXPORTED_METHOD inject_token( task& self );

#if __TBB_TASK_GROUP_CONTEXT
    void clear_filters();
#endif
};

//------------------------------------------------------------------------
// Support for lambda-friendly parallel_pipeline interface
//------------------------------------------------------------------------

namespace interface6 {

namespace internal {
    template<typename T, typename U, typename Body> class concrete_filter;
}

class flow_control {
    bool is_pipeline_stopped;
    flow_control() { is_pipeline_stopped = false; }
    template<typename T, typename U, typename Body> friend class internal::concrete_filter;
public:
    void stop() { is_pipeline_stopped = true; }
};

namespace internal {

template<typename T> struct tbb_large_object {enum { value = sizeof(T) > sizeof(void *) }; };

// Obtain type properties in one or another way
#if   __TBB_CPP11_TYPE_PROPERTIES_PRESENT
template<typename T> struct tbb_trivially_copyable { enum { value = std::is_trivially_copyable<T>::value }; };
#elif __TBB_TR1_TYPE_PROPERTIES_IN_STD_PRESENT
template<typename T> struct tbb_trivially_copyable { enum { value = std::has_trivial_copy_constructor<T>::value }; };
#else
// Explicitly list the types we wish to be placed as-is in the pipeline input_buffers.
template<typename T> struct tbb_trivially_copyable { enum { value = false }; };
template<typename T> struct tbb_trivially_copyable <T*> { enum { value = true }; };
template<> struct tbb_trivially_copyable <short> { enum { value = true }; };
template<> struct tbb_trivially_copyable <unsigned short> { enum { value = true }; };
template<> struct tbb_trivially_copyable <int> { enum { value = !tbb_large_object<int>::value }; };
template<> struct tbb_trivially_copyable <unsigned int> { enum { value = !tbb_large_object<int>::value }; };
template<> struct tbb_trivially_copyable <long> { enum { value = !tbb_large_object<long>::value }; };
template<> struct tbb_trivially_copyable <unsigned long> { enum { value = !tbb_large_object<long>::value }; };
template<> struct tbb_trivially_copyable <float> { enum { value = !tbb_large_object<float>::value }; };
template<> struct tbb_trivially_copyable <double> { enum { value = !tbb_large_object<double>::value }; };
#endif // Obtaining type properties

template<typename T> struct is_large_object {enum { value = tbb_large_object<T>::value || !tbb_trivially_copyable<T>::value }; };

template<typename T, bool> class token_helper;

// large object helper (uses tbb_allocator)
template<typename T>
class token_helper<T, true> {
    public:
    typedef typename tbb::tbb_allocator<T> allocator;
    typedef T* pointer;
    typedef T value_type;
    static pointer create_token(const value_type & source) {
        pointer output_t = allocator().allocate(1);
        return new (output_t) T(source);
    }
    static value_type & token(pointer & t) { return *t;}
    static void * cast_to_void_ptr(pointer ref) { return (void *) ref; }
    static pointer cast_from_void_ptr(void * ref) { return (pointer)ref; }
    static void destroy_token(pointer token) {
        allocator().destroy(token);
        allocator().deallocate(token,1);
    }
};

// pointer specialization
template<typename T>
class token_helper<T*, false > {
    public:
    typedef T* pointer;
    typedef T* value_type;
    static pointer create_token(const value_type & source) { return source; }
    static value_type & token(pointer & t) { return t;}
    static void * cast_to_void_ptr(pointer ref) { return (void *)ref; }
    static pointer cast_from_void_ptr(void * ref) { return (pointer)ref; }
    static void destroy_token( pointer /*token*/) {}
};

// small object specialization (converts void* to the correct type, passes objects directly.)
template<typename T>
class token_helper<T, false> {
    typedef union {
        T actual_value;
        void * void_overlay;
    } type_to_void_ptr_map;
    public:
    typedef T pointer;  // not really a pointer in this case.
    typedef T value_type;
    static pointer create_token(const value_type & source) {
        return source; }
    static value_type & token(pointer & t) { return t;}
    static void * cast_to_void_ptr(pointer ref) {
        type_to_void_ptr_map mymap;
        mymap.void_overlay = NULL;
        mymap.actual_value = ref;
        return mymap.void_overlay;
    }
    static pointer cast_from_void_ptr(void * ref) {
        type_to_void_ptr_map mymap;
        mymap.void_overlay = ref;
        return mymap.actual_value;
    }
    static void destroy_token( pointer /*token*/) {}
};

template<typename T, typename U, typename Body>
class concrete_filter: public tbb::filter {
    const Body& my_body;
    typedef token_helper<T,is_large_object<T>::value > t_helper;
    typedef typename t_helper::pointer t_pointer;
    typedef token_helper<U,is_large_object<U>::value > u_helper;
    typedef typename u_helper::pointer u_pointer;

    /*override*/ void* operator()(void* input) {
        t_pointer temp_input = t_helper::cast_from_void_ptr(input);
        u_pointer output_u = u_helper::create_token(my_body(t_helper::token(temp_input)));
        t_helper::destroy_token(temp_input);
        return u_helper::cast_to_void_ptr(output_u);
    }

    /*override*/ void finalize(void * input) {
        t_pointer temp_input = t_helper::cast_from_void_ptr(input);
        t_helper::destroy_token(temp_input);
    }

public:
    concrete_filter(tbb::filter::mode filter_mode, const Body& body) : filter(filter_mode), my_body(body) {}
};

// input
template<typename U, typename Body>
class concrete_filter<void,U,Body>: public filter {
    const Body& my_body;
    typedef token_helper<U, is_large_object<U>::value > u_helper;
    typedef typename u_helper::pointer u_pointer;

    /*override*/void* operator()(void*) {
        flow_control control;
        u_pointer output_u = u_helper::create_token(my_body(control));
        if(control.is_pipeline_stopped) {
            u_helper::destroy_token(output_u);
            set_end_of_input();
            return NULL;
        }
        return u_helper::cast_to_void_ptr(output_u);
    }

public:
    concrete_filter(tbb::filter::mode filter_mode, const Body& body) :
        filter(static_cast<tbb::filter::mode>(filter_mode | filter_may_emit_null)),
        my_body(body)
    {}
};

template<typename T, typename Body>
class concrete_filter<T,void,Body>: public filter {
    const Body& my_body;
    typedef token_helper<T, is_large_object<T>::value > t_helper;
    typedef typename t_helper::pointer t_pointer;

    /*override*/ void* operator()(void* input) {
        t_pointer temp_input = t_helper::cast_from_void_ptr(input);
        my_body(t_helper::token(temp_input));
        t_helper::destroy_token(temp_input);
        return NULL;
    }
    /*override*/ void finalize(void* input) {
        t_pointer temp_input = t_helper::cast_from_void_ptr(input);
        t_helper::destroy_token(temp_input);
    }

public:
    concrete_filter(tbb::filter::mode filter_mode, const Body& body) : filter(filter_mode), my_body(body) {}
};

template<typename Body>
class concrete_filter<void,void,Body>: public filter {
    const Body& my_body;

    /*override*/ void* operator()(void*) {
        flow_control control;
        my_body(control);
        void* output = control.is_pipeline_stopped ? NULL : (void*)(intptr_t)-1;
        return output;
    }
public:
    concrete_filter(filter::mode filter_mode, const Body& body) : filter(filter_mode), my_body(body) {}
};


class pipeline_proxy {
    tbb::pipeline my_pipe;
public:
    pipeline_proxy( const filter_t<void,void>& filter_chain );
    ~pipeline_proxy() {
        while( filter* f = my_pipe.filter_list )
            delete f; // filter destructor removes it from the pipeline
    }
    tbb::pipeline* operator->() { return &my_pipe; }
};


class filter_node: tbb::internal::no_copy {
    tbb::atomic<intptr_t> ref_count;
protected:
    filter_node() {
        ref_count = 0;
#ifdef __TBB_TEST_FILTER_NODE_COUNT
        ++(__TBB_TEST_FILTER_NODE_COUNT);
#endif
    }
public:
    virtual void add_to( pipeline& ) = 0;
    void add_ref() {++ref_count;}
    void remove_ref() {
        __TBB_ASSERT(ref_count>0,"ref_count underflow");
        if( --ref_count==0 )
            delete this;
    }
    virtual ~filter_node() {
#ifdef __TBB_TEST_FILTER_NODE_COUNT
        --(__TBB_TEST_FILTER_NODE_COUNT);
#endif
    }
};

template<typename T, typename U, typename Body>
class filter_node_leaf: public filter_node  {
    const tbb::filter::mode mode;
    const Body body;
    /*override*/void add_to( pipeline& p ) {
        concrete_filter<T,U,Body>* f = new concrete_filter<T,U,Body>(mode,body);
        p.add_filter( *f );
    }
public:
    filter_node_leaf( tbb::filter::mode m, const Body& b ) : mode(m), body(b) {}
};

class filter_node_join: public filter_node {
    friend class filter_node; // to suppress GCC 3.2 warnings
    filter_node& left;
    filter_node& right;
    /*override*/~filter_node_join() {
       left.remove_ref();
       right.remove_ref();
    }
    /*override*/void add_to( pipeline& p ) {
        left.add_to(p);
        right.add_to(p);
    }
public:
    filter_node_join( filter_node& x, filter_node& y ) : left(x), right(y) {
       left.add_ref();
       right.add_ref();
    }
};

} // namespace internal

template<typename T, typename U, typename Body>
filter_t<T,U> make_filter(tbb::filter::mode mode, const Body& body) {
    return new internal::filter_node_leaf<T,U,Body>(mode, body);
}

template<typename T, typename V, typename U>
filter_t<T,U> operator& (const filter_t<T,V>& left, const filter_t<V,U>& right) {
    __TBB_ASSERT(left.root,"cannot use default-constructed filter_t as left argument of '&'");
    __TBB_ASSERT(right.root,"cannot use default-constructed filter_t as right argument of '&'");
    return new internal::filter_node_join(*left.root,*right.root);
}

template<typename T, typename U>
class filter_t {
    typedef internal::filter_node filter_node;
    filter_node* root;
    filter_t( filter_node* root_ ) : root(root_) {
        root->add_ref();
    }
    friend class internal::pipeline_proxy;
    template<typename T_, typename U_, typename Body>
    friend filter_t<T_,U_> make_filter(tbb::filter::mode, const Body& );
    template<typename T_, typename V_, typename U_>
    friend filter_t<T_,U_> operator& (const filter_t<T_,V_>& , const filter_t<V_,U_>& );
public:
    // TODO: add move-constructors, move-assignment, etc. where C++11 is available.
    filter_t() : root(NULL) {}
    filter_t( const filter_t<T,U>& rhs ) : root(rhs.root) {
        if( root ) root->add_ref();
    }
    template<typename Body>
    filter_t( tbb::filter::mode mode, const Body& body ) :
        root( new internal::filter_node_leaf<T,U,Body>(mode, body) ) {
        root->add_ref();
    }

    void operator=( const filter_t<T,U>& rhs ) {
        // Order of operations below carefully chosen so that reference counts remain correct
        // in unlikely event that remove_ref throws exception.
        filter_node* old = root;
        root = rhs.root;
        if( root ) root->add_ref();
        if( old ) old->remove_ref();
    }
    ~filter_t() {
        if( root ) root->remove_ref();
    }
    void clear() {
        // Like operator= with filter_t() on right side.
        if( root ) {
            filter_node* old = root;
            root = NULL;
            old->remove_ref();
        }
    }
};

inline internal::pipeline_proxy::pipeline_proxy( const filter_t<void,void>& filter_chain ) : my_pipe() {
    __TBB_ASSERT( filter_chain.root, "cannot apply parallel_pipeline to default-constructed filter_t"  );
    filter_chain.root->add_to(my_pipe);
}

inline void parallel_pipeline(size_t max_number_of_live_tokens, const filter_t<void,void>& filter_chain
#if __TBB_TASK_GROUP_CONTEXT
    , tbb::task_group_context& context
#endif
    ) {
    internal::pipeline_proxy pipe(filter_chain);
    // tbb::pipeline::run() is called via the proxy
    pipe->run(max_number_of_live_tokens
#if __TBB_TASK_GROUP_CONTEXT
              , context
#endif
    );
}

#if __TBB_TASK_GROUP_CONTEXT
inline void parallel_pipeline(size_t max_number_of_live_tokens, const filter_t<void,void>& filter_chain) {
    tbb::task_group_context context;
    parallel_pipeline(max_number_of_live_tokens, filter_chain, context);
}
#endif // __TBB_TASK_GROUP_CONTEXT

} // interface6

using interface6::flow_control;
using interface6::filter_t;
using interface6::make_filter;
using interface6::parallel_pipeline;

} // tbb

#endif /* __TBB_pipeline_H */