summaryrefslogtreecommitdiff
path: root/boost/iostreams/chain.hpp
blob: 4e108c8b093d71f11ceb44ae907e9a13fc54a4bc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
// (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
// (C) Copyright 2003-2007 Jonathan Turkanis
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)

// See http://www.boost.org/libs/iostreams for documentation.

#ifndef BOOST_IOSTREAMS_DETAIL_CHAIN_HPP_INCLUDED
#define BOOST_IOSTREAMS_DETAIL_CHAIN_HPP_INCLUDED

#if defined(_MSC_VER)
# pragma once
#endif

#include <boost/assert.hpp>
#include <exception>
#include <iterator>                             // advance.
#include <list>
#include <memory>                               // allocator, auto_ptr or unique_ptr.
#include <typeinfo>
#include <stdexcept>                            // logic_error, out_of_range.
#include <boost/checked_delete.hpp>
#include <boost/config.hpp>                     // BOOST_MSVC, template friends,
#include <boost/detail/workaround.hpp>          // BOOST_NESTED_TEMPLATE 
#include <boost/iostreams/constants.hpp>
#include <boost/iostreams/detail/access_control.hpp>
#include <boost/iostreams/detail/char_traits.hpp>
#include <boost/iostreams/detail/push.hpp>
#include <boost/iostreams/detail/streambuf.hpp> // pubsync.
#include <boost/iostreams/detail/wrap_unwrap.hpp>
#include <boost/iostreams/device/null.hpp>
#include <boost/iostreams/positioning.hpp>
#include <boost/iostreams/traits.hpp>           // is_filter.
#include <boost/iostreams/stream_buffer.hpp>
#include <boost/next_prior.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/static_assert.hpp>
#include <boost/throw_exception.hpp>
#include <boost/type_traits/is_convertible.hpp>
#include <boost/type.hpp>
#include <boost/iostreams/detail/execute.hpp>

// Sometimes type_info objects must be compared by name. Borrowed from
// Boost.Python and Boost.Function.
#if defined(__GNUC__) || \
     defined(_AIX) || \
    (defined(__sgi) && defined(__host_mips)) || \
    (defined(linux) && defined(__INTEL_COMPILER) && defined(__ICC)) \
    /**/
# include <cstring>
# define BOOST_IOSTREAMS_COMPARE_TYPE_ID(X,Y) \
     (std::strcmp((X).name(),(Y).name()) == 0)
#else
# define BOOST_IOSTREAMS_COMPARE_TYPE_ID(X,Y) ((X)==(Y))
#endif

// Deprecated. Unused.
#define BOOST_IOSTREAMS_COMPONENT_TYPE(chain, index) \
    chain.component_type( index ) \
    /**/

// Deprecated. Unused.
#define BOOST_IOSTREAMS_COMPONENT(chain, index, target) \
    chain.component< target >( index ) \
    /**/

namespace boost { namespace iostreams {

//--------------Definition of chain and wchain--------------------------------//

namespace detail {

template<typename Chain> class chain_client;

//
// Concept name: Chain.
// Description: Represents a chain of stream buffers which provides access
//     to the first buffer in the chain and sends notifications when the
//     streambufs are added to or removed from chain.
// Refines: Closable device with mode equal to typename Chain::mode.
// Models: chain, converting_chain.
// Example:
//
//    class chain {
//    public:
//        typedef xxx chain_type;
//        typedef xxx client_type;
//        typedef xxx mode;
//        bool is_complete() const;                  // Ready for i/o.
//        template<typename T>
//        void push( const T& t,                     // Adds a stream buffer to
//                   streamsize,                     // chain, based on t, with
//                   streamsize );                   // given buffer and putback
//                                                   // buffer sizes. Pass -1 to
//                                                   // request default size.
//    protected:
//        void register_client(client_type* client); // Associate client.
//        void notify();                             // Notify client.
//    };
//

//
// Description: Represents a chain of filters with an optional device at the
//      end.
// Template parameters:
//      Self - A class deriving from the current instantiation of this template.
//          This is an example of the Curiously Recurring Template Pattern.
//      Ch - The character type.
//      Tr - The character traits type.
//      Alloc - The allocator type.
//      Mode - A mode tag.
//
template<typename Self, typename Ch, typename Tr, typename Alloc, typename Mode>
class chain_base {
public:
    typedef Ch                                     char_type;
    BOOST_IOSTREAMS_STREAMBUF_TYPEDEFS(Tr)
    typedef Alloc                                  allocator_type;
    typedef Mode                                   mode;
    struct category
        : Mode,
          device_tag
        { };
    typedef chain_client<Self>                     client_type;
    friend class chain_client<Self>;
private:
    typedef linked_streambuf<Ch>                   streambuf_type;
    typedef std::list<streambuf_type*>             list_type;
    typedef chain_base<Self, Ch, Tr, Alloc, Mode>  my_type;
protected:
    chain_base() : pimpl_(new chain_impl) { }
    chain_base(const chain_base& rhs): pimpl_(rhs.pimpl_) { }
public:

    // dual_use is a pseudo-mode to facilitate filter writing, 
    // not a genuine mode.
    BOOST_STATIC_ASSERT((!is_convertible<mode, dual_use>::value));

    //----------Buffer sizing-------------------------------------------------//

    // Sets the size of the buffer created for the devices to be added to this
    // chain. Does not affect the size of the buffer for devices already
    // added.
    void set_device_buffer_size(std::streamsize n) 
        { pimpl_->device_buffer_size_ = n; }

    // Sets the size of the buffer created for the filters to be added
    // to this chain. Does not affect the size of the buffer for filters already
    // added.
    void set_filter_buffer_size(std::streamsize n) 
        { pimpl_->filter_buffer_size_ = n; }

    // Sets the size of the putback buffer for filters and devices to be added
    // to this chain. Does not affect the size of the buffer for filters or
    // devices already added.
    void set_pback_size(std::streamsize n) 
        { pimpl_->pback_size_ = n; }

    //----------Device interface----------------------------------------------//

    std::streamsize read(char_type* s, std::streamsize n);
    std::streamsize write(const char_type* s, std::streamsize n);
    std::streampos seek(stream_offset off, BOOST_IOS::seekdir way);

    //----------Direct component access---------------------------------------//

    const std::type_info& component_type(int n) const
    {
        if (static_cast<size_type>(n) >= size())
            boost::throw_exception(std::out_of_range("bad chain offset"));
        return (*boost::next(list().begin(), n))->component_type();
    }

    // Deprecated.
    template<int N>
    const std::type_info& component_type() const { return component_type(N); }

    template<typename T>
    T* component(int n) const { return component(n, boost::type<T>()); }

    // Deprecated.
    template<int N, typename T> 
    T* component() const { return component<T>(N); }

#if !BOOST_WORKAROUND(BOOST_MSVC, == 1310)
    private:
#endif
    template<typename T>
    T* component(int n, boost::type<T>) const
    {
        if (static_cast<size_type>(n) >= size())
            boost::throw_exception(std::out_of_range("bad chain offset"));
        streambuf_type* link = *boost::next(list().begin(), n);
        if (BOOST_IOSTREAMS_COMPARE_TYPE_ID(link->component_type(), typeid(T)))
            return static_cast<T*>(link->component_impl());
        else
            return 0;
    }
public:

    //----------Container-like interface--------------------------------------//

    typedef typename list_type::size_type size_type;
    streambuf_type& front() { return *list().front(); }
    BOOST_IOSTREAMS_DEFINE_PUSH(push, mode, char_type, push_impl)
    void pop();
    bool empty() const { return list().empty(); }
    size_type size() const { return list().size(); }
    void reset();

    //----------Additional i/o functions--------------------------------------//

    // Returns true if this chain is non-empty and its final link
    // is a source or sink, i.e., if it is ready to perform i/o.
    bool is_complete() const;
    bool auto_close() const;
    void set_auto_close(bool close);
    bool sync() { return front().BOOST_IOSTREAMS_PUBSYNC() != -1; }
    bool strict_sync();
private:
    template<typename T>
    void push_impl(const T& t, std::streamsize buffer_size = -1, 
                   std::streamsize pback_size = -1)
    {
        typedef typename iostreams::category_of<T>::type  category;
        typedef typename unwrap_ios<T>::type              component_type;
        typedef stream_buffer<
                    component_type,
                    BOOST_IOSTREAMS_CHAR_TRAITS(char_type),
                    Alloc, Mode
                >                                         streambuf_t;
        typedef typename list_type::iterator              iterator;
        BOOST_STATIC_ASSERT((is_convertible<category, Mode>::value));
        if (is_complete())
            boost::throw_exception(std::logic_error("chain complete"));
        streambuf_type* prev = !empty() ? list().back() : 0;
        buffer_size =
            buffer_size != -1 ?
                buffer_size :
                iostreams::optimal_buffer_size(t);
        pback_size =
            pback_size != -1 ?
                pback_size :
                pimpl_->pback_size_;
                
#if defined(BOOST_NO_CXX11_SMART_PTR)

        std::auto_ptr<streambuf_t>
            buf(new streambuf_t(t, buffer_size, pback_size));
            
#else

        std::unique_ptr<streambuf_t>
            buf(new streambuf_t(t, buffer_size, pback_size));
            
#endif
            
        list().push_back(buf.get());
        buf.release();
        if (is_device<component_type>::value) {
            pimpl_->flags_ |= f_complete | f_open;
            for ( iterator first = list().begin(),
                           last = list().end();
                  first != last;
                  ++first )
            {
                (*first)->set_needs_close();
            }
        }
        if (prev) prev->set_next(list().back());
        notify();
    }

    list_type& list() { return pimpl_->links_; }
    const list_type& list() const { return pimpl_->links_; }
    void register_client(client_type* client) { pimpl_->client_ = client; }
    void notify() { if (pimpl_->client_) pimpl_->client_->notify(); }

    //----------Nested classes------------------------------------------------//

    static void close(streambuf_type* b, BOOST_IOS::openmode m)
    {
        if (m == BOOST_IOS::out && is_convertible<Mode, output>::value)
            b->BOOST_IOSTREAMS_PUBSYNC();
        b->close(m);
    }

    static void set_next(streambuf_type* b, streambuf_type* next)
    { b->set_next(next); }

    static void set_auto_close(streambuf_type* b, bool close)
    { b->set_auto_close(close); }

    struct closer {
        typedef streambuf_type* argument_type;
        typedef void result_type;
        closer(BOOST_IOS::openmode m) : mode_(m) { }
        void operator() (streambuf_type* b)
        {
            close(b, mode_);
        }
        BOOST_IOS::openmode mode_;
    };
    friend struct closer;

    enum flags {
        f_complete = 1,
        f_open = 2,
        f_auto_close = 4
    };

    struct chain_impl {
        chain_impl()
            : client_(0), device_buffer_size_(default_device_buffer_size),
              filter_buffer_size_(default_filter_buffer_size),
              pback_size_(default_pback_buffer_size),
              flags_(f_auto_close)
            { }
        ~chain_impl()
            {
                try { close(); } catch (...) { }
                try { reset(); } catch (...) { }
            }
        void close()
            {
                if ((flags_ & f_open) != 0) {
                    flags_ &= ~f_open;
                    stream_buffer< basic_null_device<Ch, Mode> > null;
                    if ((flags_ & f_complete) == 0) {
                        null.open(basic_null_device<Ch, Mode>());
                        set_next(links_.back(), &null);
                    }
                    links_.front()->BOOST_IOSTREAMS_PUBSYNC();
                    try {
                        boost::iostreams::detail::execute_foreach(
                            links_.rbegin(), links_.rend(), 
                            closer(BOOST_IOS::in)
                        );
                    } catch (...) {
                        try {
                            boost::iostreams::detail::execute_foreach(
                                links_.begin(), links_.end(), 
                                closer(BOOST_IOS::out)
                            );
                        } catch (...) { }
                        throw;
                    }
                    boost::iostreams::detail::execute_foreach(
                        links_.begin(), links_.end(), 
                        closer(BOOST_IOS::out)
                    );
                }
            }
        void reset()
            {
                typedef typename list_type::iterator iterator;
                for ( iterator first = links_.begin(),
                               last = links_.end();
                      first != last;
                      ++first )
                {
                    if ( (flags_ & f_complete) == 0 ||
                         (flags_ & f_auto_close) == 0 )
                    {
                        set_auto_close(*first, false);
                    }
                    streambuf_type* buf = 0;
                    std::swap(buf, *first);
                    delete buf;
                }
                links_.clear();
                flags_ &= ~f_complete;
                flags_ &= ~f_open;
            }
        list_type        links_;
        client_type*     client_;
        std::streamsize  device_buffer_size_,
                         filter_buffer_size_,
                         pback_size_;
        int              flags_;
    };
    friend struct chain_impl;

    //----------Member data---------------------------------------------------//

private:
    shared_ptr<chain_impl> pimpl_;
};

} // End namespace detail.

//
// Macro: BOOST_IOSTREAMS_DECL_CHAIN(name, category)
// Description: Defines a template derived from chain_base appropriate for a
//      particular i/o category. The template has the following parameters:
//      Ch - The character type.
//      Tr - The character traits type.
//      Alloc - The allocator type.
// Macro parameters:
//      name_ - The name of the template to be defined.
//      category_ - The i/o category of the template to be defined.
//
#define BOOST_IOSTREAMS_DECL_CHAIN(name_, default_char_) \
    template< typename Mode, typename Ch = default_char_, \
              typename Tr = BOOST_IOSTREAMS_CHAR_TRAITS(Ch), \
              typename Alloc = std::allocator<Ch> > \
    class name_ : public boost::iostreams::detail::chain_base< \
                            name_<Mode, Ch, Tr, Alloc>, \
                            Ch, Tr, Alloc, Mode \
                         > \
    { \
    public: \
        struct category : device_tag, Mode { }; \
        typedef Mode                                   mode; \
    private: \
        typedef boost::iostreams::detail::chain_base< \
                    name_<Mode, Ch, Tr, Alloc>, \
                    Ch, Tr, Alloc, Mode \
                >                                      base_type; \
    public: \
        typedef Ch                                     char_type; \
        typedef Tr                                     traits_type; \
        typedef typename traits_type::int_type         int_type; \
        typedef typename traits_type::off_type         off_type; \
        name_() { } \
        name_(const name_& rhs) : base_type(rhs) { } \
        name_& operator=(const name_& rhs) \
        { base_type::operator=(rhs); return *this; } \
    }; \
    /**/
BOOST_IOSTREAMS_DECL_CHAIN(chain, char)
BOOST_IOSTREAMS_DECL_CHAIN(wchain, wchar_t)
#undef BOOST_IOSTREAMS_DECL_CHAIN

//--------------Definition of chain_client------------------------------------//

namespace detail {

//
// Template name: chain_client
// Description: Class whose instances provide access to an underlying chain
//      using an interface similar to the chains.
// Subclasses: the various stream and stream buffer templates.
//
template<typename Chain>
class chain_client {
public:
    typedef Chain                             chain_type;
    typedef typename chain_type::char_type    char_type;
    typedef typename chain_type::traits_type  traits_type;
    typedef typename chain_type::size_type    size_type;
    typedef typename chain_type::mode         mode;

    chain_client(chain_type* chn = 0) : chain_(chn ) { }
    chain_client(chain_client* client) : chain_(client->chain_) { }
    virtual ~chain_client() { }

    const std::type_info& component_type(int n) const
    { return chain_->component_type(n); }

    // Deprecated.
    template<int N>
    const std::type_info& component_type() const
    { return chain_->BOOST_NESTED_TEMPLATE component_type<N>(); }

    template<typename T>
    T* component(int n) const
    { return chain_->BOOST_NESTED_TEMPLATE component<T>(n); }

    // Deprecated.
    template<int N, typename T>
    T* component() const
    { return chain_->BOOST_NESTED_TEMPLATE component<N, T>(); }

    bool is_complete() const { return chain_->is_complete(); }
    bool auto_close() const { return chain_->auto_close(); }
    void set_auto_close(bool close) { chain_->set_auto_close(close); }
    bool strict_sync() { return chain_->strict_sync(); }
    void set_device_buffer_size(std::streamsize n)
        { chain_->set_device_buffer_size(n); }
    void set_filter_buffer_size(std::streamsize n)
        { chain_->set_filter_buffer_size(n); }
    void set_pback_size(std::streamsize n) { chain_->set_pback_size(n); }
    BOOST_IOSTREAMS_DEFINE_PUSH(push, mode, char_type, push_impl)
    void pop() { chain_->pop(); }
    bool empty() const { return chain_->empty(); }
    size_type size() const { return chain_->size(); }
    void reset() { chain_->reset(); }

    // Returns a copy of the underlying chain.
    chain_type filters() { return *chain_; }
    chain_type filters() const { return *chain_; }
protected:
    template<typename T>
    void push_impl(const T& t BOOST_IOSTREAMS_PUSH_PARAMS())
    { chain_->push(t BOOST_IOSTREAMS_PUSH_ARGS()); }
    chain_type& ref() { return *chain_; }
    void set_chain(chain_type* c)
    { chain_ = c; chain_->register_client(this); }
#if !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS) && \
    (!BOOST_WORKAROUND(__BORLANDC__, < 0x600))
    template<typename S, typename C, typename T, typename A, typename M>
    friend class chain_base;
#else
    public:
#endif
    virtual void notify() { }
private:
    chain_type* chain_;
};

//--------------Implementation of chain_base----------------------------------//

template<typename Self, typename Ch, typename Tr, typename Alloc, typename Mode>
inline std::streamsize chain_base<Self, Ch, Tr, Alloc, Mode>::read
    (char_type* s, std::streamsize n)
{ return iostreams::read(*list().front(), s, n); }

template<typename Self, typename Ch, typename Tr, typename Alloc, typename Mode>
inline std::streamsize chain_base<Self, Ch, Tr, Alloc, Mode>::write
    (const char_type* s, std::streamsize n)
{ return iostreams::write(*list().front(), s, n); }

template<typename Self, typename Ch, typename Tr, typename Alloc, typename Mode>
inline std::streampos chain_base<Self, Ch, Tr, Alloc, Mode>::seek
    (stream_offset off, BOOST_IOS::seekdir way)
{ return iostreams::seek(*list().front(), off, way); }

template<typename Self, typename Ch, typename Tr, typename Alloc, typename Mode>
void chain_base<Self, Ch, Tr, Alloc, Mode>::reset()
{
    using namespace std;
    pimpl_->close();
    pimpl_->reset();
}

template<typename Self, typename Ch, typename Tr, typename Alloc, typename Mode>
bool chain_base<Self, Ch, Tr, Alloc, Mode>::is_complete() const
{
    return (pimpl_->flags_ & f_complete) != 0;
}

template<typename Self, typename Ch, typename Tr, typename Alloc, typename Mode>
bool chain_base<Self, Ch, Tr, Alloc, Mode>::auto_close() const
{
    return (pimpl_->flags_ & f_auto_close) != 0;
}

template<typename Self, typename Ch, typename Tr, typename Alloc, typename Mode>
void chain_base<Self, Ch, Tr, Alloc, Mode>::set_auto_close(bool close)
{
    pimpl_->flags_ =
        (pimpl_->flags_ & ~f_auto_close) |
        (close ? f_auto_close : 0);
}

template<typename Self, typename Ch, typename Tr, typename Alloc, typename Mode>
bool chain_base<Self, Ch, Tr, Alloc, Mode>::strict_sync()
{
    typedef typename list_type::iterator iterator;
    bool result = true;
    for ( iterator first = list().begin(),
                   last = list().end();
          first != last;
          ++first )
    {
        bool s = (*first)->strict_sync();
        result = result && s;
    }
    return result;
}

template<typename Self, typename Ch, typename Tr, typename Alloc, typename Mode>
void chain_base<Self, Ch, Tr, Alloc, Mode>::pop()
{
    BOOST_ASSERT(!empty());
    if (auto_close())
        pimpl_->close();
    streambuf_type* buf = 0;
    std::swap(buf, list().back());
    buf->set_auto_close(false);
    buf->set_next(0);
    delete buf;
    list().pop_back();
    pimpl_->flags_ &= ~f_complete;
    if (auto_close() || list().empty())
        pimpl_->flags_ &= ~f_open;
}

} // End namespace detail.

} } // End namespaces iostreams, boost.

#endif // #ifndef BOOST_IOSTREAMS_DETAIL_CHAIN_HPP_INCLUDED