pipeline.h

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/*
    Copyright 2005-2010 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 <cstddef>

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 interface5 {
    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));}
    
    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 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)
    {}

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;
    }


    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;


    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 | filter::exact_exception_propagation))
    {}
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::interface5::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 interface5 {

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, typename U, typename Body>
class concrete_filter: public tbb::filter {
    Body my_body;

    /*override*/ void* operator()(void* input) {
        T* temp_input = (T*)input;
        // Call user's operator()() here
        void* output = (void*) new U(my_body(*temp_input)); 
        delete temp_input;
        return output;
    }

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

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

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

template<typename T, typename Body>
class concrete_filter<T,void,Body>: public filter {
    Body my_body;
   
    /*override*/ void* operator()(void* input) {
        T* temp_input = (T*)input;
        my_body(*temp_input);
        delete temp_input;
        return NULL;
    }
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 {
    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:
    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

} // interface5

using interface5::flow_control;
using interface5::filter_t;
using interface5::make_filter;
using interface5::parallel_pipeline;

} // tbb

#endif /* __TBB_pipeline_H */