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apr_buckets.h
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16 /**
17  * @file apr_buckets.h
18  * @brief APR-UTIL Buckets/Bucket Brigades
19  */
20 
21 #ifndef APR_BUCKETS_H
22 #define APR_BUCKETS_H
23 
24 #if defined(APR_BUCKET_DEBUG) && !defined(APR_RING_DEBUG)
25 #define APR_RING_DEBUG
26 #endif
27 
28 #include "apu.h"
29 #include "apr_network_io.h"
30 #include "apr_file_io.h"
31 #include "apr_general.h"
32 #include "apr_mmap.h"
33 #include "apr_errno.h"
34 #include "apr_ring.h"
35 #include "apr.h"
36 #if APR_HAVE_SYS_UIO_H
37 #include <sys/uio.h> /* for struct iovec */
38 #endif
39 #if APR_HAVE_STDARG_H
40 #include <stdarg.h>
41 #endif
42 
43 #ifdef __cplusplus
44 extern "C" {
45 #endif
46 
47 /**
48  * @defgroup APR_Util_Bucket_Brigades Bucket Brigades
49  * @ingroup APR_Util
50  * @{
51  */
52 
53 /** default bucket buffer size - 8KB minus room for memory allocator headers */
54 #define APR_BUCKET_BUFF_SIZE 8000
55 
56 /** Determines how a bucket or brigade should be read */
57 typedef enum {
58  APR_BLOCK_READ, /**< block until data becomes available */
59  APR_NONBLOCK_READ /**< return immediately if no data is available */
61 
62 /**
63  * The one-sentence buzzword-laden overview: Bucket brigades represent
64  * a complex data stream that can be passed through a layered IO
65  * system without unnecessary copying. A longer overview follows...
66  *
67  * A bucket brigade is a doubly linked list (ring) of buckets, so we
68  * aren't limited to inserting at the front and removing at the end.
69  * Buckets are only passed around as members of a brigade, although
70  * singleton buckets can occur for short periods of time.
71  *
72  * Buckets are data stores of various types. They can refer to data in
73  * memory, or part of a file or mmap area, or the output of a process,
74  * etc. Buckets also have some type-dependent accessor functions:
75  * read, split, copy, setaside, and destroy.
76  *
77  * read returns the address and size of the data in the bucket. If the
78  * data isn't in memory then it is read in and the bucket changes type
79  * so that it can refer to the new location of the data. If all the
80  * data doesn't fit in the bucket then a new bucket is inserted into
81  * the brigade to hold the rest of it.
82  *
83  * split divides the data in a bucket into two regions. After a split
84  * the original bucket refers to the first part of the data and a new
85  * bucket inserted into the brigade after the original bucket refers
86  * to the second part of the data. Reference counts are maintained as
87  * necessary.
88  *
89  * setaside ensures that the data in the bucket has a long enough
90  * lifetime. Sometimes it is convenient to create a bucket referring
91  * to data on the stack in the expectation that it will be consumed
92  * (output to the network) before the stack is unwound. If that
93  * expectation turns out not to be valid, the setaside function is
94  * called to move the data somewhere safer.
95  *
96  * copy makes a duplicate of the bucket structure as long as it's
97  * possible to have multiple references to a single copy of the
98  * data itself. Not all bucket types can be copied.
99  *
100  * destroy maintains the reference counts on the resources used by a
101  * bucket and frees them if necessary.
102  *
103  * Note: all of the above functions have wrapper macros (apr_bucket_read(),
104  * apr_bucket_destroy(), etc), and those macros should be used rather
105  * than using the function pointers directly.
106  *
107  * To write a bucket brigade, they are first made into an iovec, so that we
108  * don't write too little data at one time. Currently we ignore compacting the
109  * buckets into as few buckets as possible, but if we really want good
110  * performance, then we need to compact the buckets before we convert to an
111  * iovec, or possibly while we are converting to an iovec.
112  */
113 
114 /*
115  * Forward declaration of the main types.
116  */
117 
118 /** @see apr_bucket_brigade */
120 /** @see apr_bucket */
121 typedef struct apr_bucket apr_bucket;
122 /** @see apr_bucket_alloc_t */
124 
125 /** @see apr_bucket_type_t */
127 
128 /**
129  * Basic bucket type
130  */
132  /**
133  * The name of the bucket type
134  */
135  const char *name;
136  /**
137  * The number of functions this bucket understands. Can not be less than
138  * five.
139  */
140  int num_func;
141  /**
142  * Whether the bucket contains metadata (ie, information that
143  * describes the regular contents of the brigade). The metadata
144  * is not returned by apr_bucket_read() and is not indicated by
145  * the ->length of the apr_bucket itself. In other words, an
146  * empty bucket is safe to arbitrarily remove if and only if it
147  * contains no metadata. In this sense, "data" is just raw bytes
148  * that are the "content" of the brigade and "metadata" describes
149  * that data but is not a proper part of it.
150  */
151  enum {
152  /** This bucket type represents actual data to send to the client. */
154  /** This bucket type represents metadata. */
156  } is_metadata;
157  /**
158  * Free the private data and any resources used by the bucket (if they
159  * aren't shared with another bucket). This function is required to be
160  * implemented for all bucket types, though it might be a no-op on some
161  * of them (namely ones that never allocate any private data structures).
162  * @param data The private data pointer from the bucket to be destroyed
163  */
164  void (*destroy)(void *data);
165 
166  /**
167  * Read the data from the bucket. This is required to be implemented
168  * for all bucket types.
169  * @param b The bucket to read from
170  * @param str A place to store the data read. Allocation should only be
171  * done if absolutely necessary.
172  * @param len The amount of data read.
173  * @param block Should this read function block if there is more data that
174  * cannot be read immediately.
175  */
176  apr_status_t (*read)(apr_bucket *b, const char **str, apr_size_t *len,
177  apr_read_type_e block);
178 
179  /**
180  * Make it possible to set aside the data for at least as long as the
181  * given pool. Buckets containing data that could potentially die before
182  * this pool (e.g. the data resides on the stack, in a child pool of
183  * the given pool, or in a disjoint pool) must somehow copy, shift, or
184  * transform the data to have the proper lifetime.
185  * @param e The bucket to convert
186  * @remark Some bucket types contain data that will always outlive the
187  * bucket itself. For example no data (EOS and FLUSH), or the data
188  * resides in global, constant memory (IMMORTAL), or the data is on
189  * the heap (HEAP). For these buckets, apr_bucket_setaside_noop can
190  * be used.
191  */
193 
194  /**
195  * Split one bucket in two at the specified position by duplicating
196  * the bucket structure (not the data) and modifying any necessary
197  * start/end/offset information. If it's not possible to do this
198  * for the bucket type (perhaps the length of the data is indeterminate,
199  * as with pipe and socket buckets), then APR_ENOTIMPL is returned.
200  * @param e The bucket to split
201  * @param point The offset of the first byte in the new bucket
202  */
203  apr_status_t (*split)(apr_bucket *e, apr_size_t point);
204 
205  /**
206  * Copy the bucket structure (not the data), assuming that this is
207  * possible for the bucket type. If it's not, APR_ENOTIMPL is returned.
208  * @param e The bucket to copy
209  * @param c Returns a pointer to the new bucket
210  */
212 
213 };
214 
215 /**
216  * apr_bucket structures are allocated on the malloc() heap and
217  * their lifetime is controlled by the parent apr_bucket_brigade
218  * structure. Buckets can move from one brigade to another e.g. by
219  * calling APR_BRIGADE_CONCAT(). In general the data in a bucket has
220  * the same lifetime as the bucket and is freed when the bucket is
221  * destroyed; if the data is shared by more than one bucket (e.g.
222  * after a split) the data is freed when the last bucket goes away.
223  */
224 struct apr_bucket {
225  /** Links to the rest of the brigade */
227  /** The type of bucket. */
229  /** The length of the data in the bucket. This could have been implemented
230  * with a function, but this is an optimization, because the most
231  * common thing to do will be to get the length. If the length is unknown,
232  * the value of this field will be (apr_size_t)(-1).
233  */
234  apr_size_t length;
235  /** The start of the data in the bucket relative to the private base
236  * pointer. The vast majority of bucket types allow a fixed block of
237  * data to be referenced by multiple buckets, each bucket pointing to
238  * a different segment of the data. That segment starts at base+start
239  * and ends at base+start+length.
240  * If the length == (apr_size_t)(-1), then start == -1.
241  */
242  apr_off_t start;
243  /** type-dependent data hangs off this pointer */
244  void *data;
245  /**
246  * Pointer to function used to free the bucket. This function should
247  * always be defined and it should be consistent with the memory
248  * function used to allocate the bucket. For example, if malloc() is
249  * used to allocate the bucket, this pointer should point to free().
250  * @param e Pointer to the bucket being freed
251  */
252  void (*free)(void *e);
253  /** The freelist from which this bucket was allocated */
255 };
256 
257 /** A list of buckets */
259  /** The pool to associate the brigade with. The data is not allocated out
260  * of the pool, but a cleanup is registered with this pool. If the
261  * brigade is destroyed by some mechanism other than pool destruction,
262  * the destroying function is responsible for killing the cleanup.
263  */
265  /** The buckets in the brigade are on this list. */
266  /*
267  * The apr_bucket_list structure doesn't actually need a name tag
268  * because it has no existence independent of struct apr_bucket_brigade;
269  * the ring macros are designed so that you can leave the name tag
270  * argument empty in this situation but apparently the Windows compiler
271  * doesn't like that.
272  */
273  APR_RING_HEAD(apr_bucket_list, apr_bucket) list;
274  /** The freelist from which this bucket was allocated */
276 };
277 
278 
279 /**
280  * Function called when a brigade should be flushed
281  */
283 
284 /*
285  * define APR_BUCKET_DEBUG if you want your brigades to be checked for
286  * validity at every possible instant. this will slow your code down
287  * substantially but is a very useful debugging tool.
288  */
289 #ifdef APR_BUCKET_DEBUG
290 
291 #define APR_BRIGADE_CHECK_CONSISTENCY(b) \
292  APR_RING_CHECK_CONSISTENCY(&(b)->list, apr_bucket, link)
293 
294 #define APR_BUCKET_CHECK_CONSISTENCY(e) \
295  APR_RING_CHECK_ELEM_CONSISTENCY((e), apr_bucket, link)
296 
297 #else
298 /**
299  * checks the ring pointers in a bucket brigade for consistency. an
300  * abort() will be triggered if any inconsistencies are found.
301  * note: this is a no-op unless APR_BUCKET_DEBUG is defined.
302  * @param b The brigade
303  */
304 #define APR_BRIGADE_CHECK_CONSISTENCY(b)
305 /**
306  * checks the brigade a bucket is in for ring consistency. an
307  * abort() will be triggered if any inconsistencies are found.
308  * note: this is a no-op unless APR_BUCKET_DEBUG is defined.
309  * @param e The bucket
310  */
311 #define APR_BUCKET_CHECK_CONSISTENCY(e)
312 #endif
313 
314 
315 /**
316  * Wrappers around the RING macros to reduce the verbosity of the code
317  * that handles bucket brigades.
318  */
319 /**
320  * The magic pointer value that indicates the head of the brigade
321  * @remark This is used to find the beginning and end of the brigade, eg:
322  * <pre>
323  * while (e != APR_BRIGADE_SENTINEL(b)) {
324  * ...
325  * e = APR_BUCKET_NEXT(e);
326  * }
327  * </pre>
328  * @param b The brigade
329  * @return The magic pointer value
330  */
331 #define APR_BRIGADE_SENTINEL(b) APR_RING_SENTINEL(&(b)->list, apr_bucket, link)
332 
333 /**
334  * Determine if the bucket brigade is empty
335  * @param b The brigade to check
336  * @return true or false
337  */
338 #define APR_BRIGADE_EMPTY(b) APR_RING_EMPTY(&(b)->list, apr_bucket, link)
339 
340 /**
341  * Return the first bucket in a brigade
342  * @param b The brigade to query
343  * @return The first bucket in the brigade
344  */
345 #define APR_BRIGADE_FIRST(b) APR_RING_FIRST(&(b)->list)
346 /**
347  * Return the last bucket in a brigade
348  * @param b The brigade to query
349  * @return The last bucket in the brigade
350  */
351 #define APR_BRIGADE_LAST(b) APR_RING_LAST(&(b)->list)
352 
353 /**
354  * Insert a list of buckets at the front of a brigade
355  * @param b The brigade to add to
356  * @param e The first bucket in a list of buckets to insert
357  */
358 #define APR_BRIGADE_INSERT_HEAD(b, e) do { \
359  apr_bucket *ap__b = (e); \
360  APR_RING_INSERT_HEAD(&(b)->list, ap__b, apr_bucket, link); \
361  APR_BRIGADE_CHECK_CONSISTENCY((b)); \
362  } while (0)
363 
364 /**
365  * Insert a list of buckets at the end of a brigade
366  * @param b The brigade to add to
367  * @param e The first bucket in a list of buckets to insert
368  */
369 #define APR_BRIGADE_INSERT_TAIL(b, e) do { \
370  apr_bucket *ap__b = (e); \
371  APR_RING_INSERT_TAIL(&(b)->list, ap__b, apr_bucket, link); \
372  APR_BRIGADE_CHECK_CONSISTENCY((b)); \
373  } while (0)
374 
375 /**
376  * Concatenate brigade b onto the end of brigade a, leaving brigade b empty
377  * @param a The first brigade
378  * @param b The second brigade
379  */
380 #define APR_BRIGADE_CONCAT(a, b) do { \
381  APR_RING_CONCAT(&(a)->list, &(b)->list, apr_bucket, link); \
382  APR_BRIGADE_CHECK_CONSISTENCY((a)); \
383  } while (0)
384 
385 /**
386  * Prepend brigade b onto the beginning of brigade a, leaving brigade b empty
387  * @param a The first brigade
388  * @param b The second brigade
389  */
390 #define APR_BRIGADE_PREPEND(a, b) do { \
391  APR_RING_PREPEND(&(a)->list, &(b)->list, apr_bucket, link); \
392  APR_BRIGADE_CHECK_CONSISTENCY((a)); \
393  } while (0)
394 
395 /**
396  * Insert a list of buckets before a specified bucket
397  * @param a The bucket to insert before
398  * @param b The buckets to insert
399  */
400 #define APR_BUCKET_INSERT_BEFORE(a, b) do { \
401  apr_bucket *ap__a = (a), *ap__b = (b); \
402  APR_RING_INSERT_BEFORE(ap__a, ap__b, link); \
403  APR_BUCKET_CHECK_CONSISTENCY(ap__a); \
404  } while (0)
405 
406 /**
407  * Insert a list of buckets after a specified bucket
408  * @param a The bucket to insert after
409  * @param b The buckets to insert
410  */
411 #define APR_BUCKET_INSERT_AFTER(a, b) do { \
412  apr_bucket *ap__a = (a), *ap__b = (b); \
413  APR_RING_INSERT_AFTER(ap__a, ap__b, link); \
414  APR_BUCKET_CHECK_CONSISTENCY(ap__a); \
415  } while (0)
416 
417 /**
418  * Get the next bucket in the list
419  * @param e The current bucket
420  * @return The next bucket
421  */
422 #define APR_BUCKET_NEXT(e) APR_RING_NEXT((e), link)
423 /**
424  * Get the previous bucket in the list
425  * @param e The current bucket
426  * @return The previous bucket
427  */
428 #define APR_BUCKET_PREV(e) APR_RING_PREV((e), link)
429 
430 /**
431  * Remove a bucket from its bucket brigade
432  * @param e The bucket to remove
433  */
434 #define APR_BUCKET_REMOVE(e) APR_RING_REMOVE((e), link)
435 
436 /**
437  * Initialize a new bucket's prev/next pointers
438  * @param e The bucket to initialize
439  */
440 #define APR_BUCKET_INIT(e) APR_RING_ELEM_INIT((e), link)
441 
442 /**
443  * Determine if a bucket contains metadata. An empty bucket is
444  * safe to arbitrarily remove if and only if this is false.
445  * @param e The bucket to inspect
446  * @return true or false
447  */
448 #define APR_BUCKET_IS_METADATA(e) ((e)->type->is_metadata)
449 
450 /**
451  * Determine if a bucket is a FLUSH bucket
452  * @param e The bucket to inspect
453  * @return true or false
454  */
455 #define APR_BUCKET_IS_FLUSH(e) ((e)->type == &apr_bucket_type_flush)
456 /**
457  * Determine if a bucket is an EOS bucket
458  * @param e The bucket to inspect
459  * @return true or false
460  */
461 #define APR_BUCKET_IS_EOS(e) ((e)->type == &apr_bucket_type_eos)
462 /**
463  * Determine if a bucket is a FILE bucket
464  * @param e The bucket to inspect
465  * @return true or false
466  */
467 #define APR_BUCKET_IS_FILE(e) ((e)->type == &apr_bucket_type_file)
468 /**
469  * Determine if a bucket is a PIPE bucket
470  * @param e The bucket to inspect
471  * @return true or false
472  */
473 #define APR_BUCKET_IS_PIPE(e) ((e)->type == &apr_bucket_type_pipe)
474 /**
475  * Determine if a bucket is a SOCKET bucket
476  * @param e The bucket to inspect
477  * @return true or false
478  */
479 #define APR_BUCKET_IS_SOCKET(e) ((e)->type == &apr_bucket_type_socket)
480 /**
481  * Determine if a bucket is a HEAP bucket
482  * @param e The bucket to inspect
483  * @return true or false
484  */
485 #define APR_BUCKET_IS_HEAP(e) ((e)->type == &apr_bucket_type_heap)
486 /**
487  * Determine if a bucket is a TRANSIENT bucket
488  * @param e The bucket to inspect
489  * @return true or false
490  */
491 #define APR_BUCKET_IS_TRANSIENT(e) ((e)->type == &apr_bucket_type_transient)
492 /**
493  * Determine if a bucket is a IMMORTAL bucket
494  * @param e The bucket to inspect
495  * @return true or false
496  */
497 #define APR_BUCKET_IS_IMMORTAL(e) ((e)->type == &apr_bucket_type_immortal)
498 #if APR_HAS_MMAP
499 /**
500  * Determine if a bucket is a MMAP bucket
501  * @param e The bucket to inspect
502  * @return true or false
503  */
504 #define APR_BUCKET_IS_MMAP(e) ((e)->type == &apr_bucket_type_mmap)
505 #endif
506 /**
507  * Determine if a bucket is a POOL bucket
508  * @param e The bucket to inspect
509  * @return true or false
510  */
511 #define APR_BUCKET_IS_POOL(e) ((e)->type == &apr_bucket_type_pool)
512 
513 /*
514  * General-purpose reference counting for the various bucket types.
515  *
516  * Any bucket type that keeps track of the resources it uses (i.e.
517  * most of them except for IMMORTAL, TRANSIENT, and EOS) needs to
518  * attach a reference count to the resource so that it can be freed
519  * when the last bucket that uses it goes away. Resource-sharing may
520  * occur because of bucket splits or buckets that refer to globally
521  * cached data. */
522 
523 /** @see apr_bucket_refcount */
525 /**
526  * The structure used to manage the shared resource must start with an
527  * apr_bucket_refcount which is updated by the general-purpose refcount
528  * code. A pointer to the bucket-type-dependent private data structure
529  * can be cast to a pointer to an apr_bucket_refcount and vice versa.
530  */
532  /** The number of references to this bucket */
533  int refcount;
534 };
535 
536 /* ***** Reference-counted bucket types ***** */
537 
538 /** @see apr_bucket_heap */
540 /**
541  * A bucket referring to data allocated off the heap.
542  */
544  /** Number of buckets using this memory */
546  /** The start of the data actually allocated. This should never be
547  * modified, it is only used to free the bucket.
548  */
549  char *base;
550  /** how much memory was allocated */
551  apr_size_t alloc_len;
552  /** function to use to delete the data */
553  void (*free_func)(void *data);
554 };
555 
556 /** @see apr_bucket_pool */
558 /**
559  * A bucket referring to data allocated from a pool
560  */
562  /** The pool bucket must be able to be easily morphed to a heap
563  * bucket if the pool gets cleaned up before all references are
564  * destroyed. This apr_bucket_heap structure is populated automatically
565  * when the pool gets cleaned up, and subsequent calls to pool_read()
566  * will result in the apr_bucket in question being morphed into a
567  * regular heap bucket. (To avoid having to do many extra refcount
568  * manipulations and b->data manipulations, the apr_bucket_pool
569  * struct actually *contains* the apr_bucket_heap struct that it
570  * will become as its first element; the two share their
571  * apr_bucket_refcount members.)
572  */
574  /** The block of data actually allocated from the pool.
575  * Segments of this block are referenced by adjusting
576  * the start and length of the apr_bucket accordingly.
577  * This will be NULL after the pool gets cleaned up.
578  */
579  const char *base;
580  /** The pool the data was allocated from. When the pool
581  * is cleaned up, this gets set to NULL as an indicator
582  * to pool_read() that the data is now on the heap and
583  * so it should morph the bucket into a regular heap
584  * bucket before continuing.
585  */
587  /** The freelist this structure was allocated from, which is
588  * needed in the cleanup phase in order to allocate space on the heap
589  */
591 };
592 
593 #if APR_HAS_MMAP
594 /** @see apr_bucket_mmap */
596 /**
597  * A bucket referring to an mmap()ed file
598  */
600  /** Number of buckets using this memory */
602  /** The mmap this sub_bucket refers to */
604 };
605 #endif
606 
607 /** @see apr_bucket_file */
609 /**
610  * A bucket referring to an file
611  */
613  /** Number of buckets using this memory */
615  /** The file this bucket refers to */
617  /** The pool into which any needed structures should
618  * be created while reading from this file bucket */
620 #if APR_HAS_MMAP
621  /** Whether this bucket should be memory-mapped if
622  * a caller tries to read from it */
623  int can_mmap;
624 #endif /* APR_HAS_MMAP */
625 };
626 
627 /** @see apr_bucket_structs */
629 /**
630  * A union of all bucket structures so we know what
631  * the max size is.
632  */
634  apr_bucket b; /**< Bucket */
635  apr_bucket_heap heap; /**< Heap */
636  apr_bucket_pool pool; /**< Pool */
637 #if APR_HAS_MMAP
638  apr_bucket_mmap mmap; /**< MMap */
639 #endif
640  apr_bucket_file file; /**< File */
641 };
642 
643 /**
644  * The amount that apr_bucket_alloc() should allocate in the common case.
645  * Note: this is twice as big as apr_bucket_structs to allow breathing
646  * room for third-party bucket types.
647  */
648 #define APR_BUCKET_ALLOC_SIZE APR_ALIGN_DEFAULT(2*sizeof(apr_bucket_structs))
649 
650 /* ***** Bucket Brigade Functions ***** */
651 /**
652  * Create a new bucket brigade. The bucket brigade is originally empty.
653  * @param p The pool to associate with the brigade. Data is not allocated out
654  * of the pool, but a cleanup is registered.
655  * @param list The bucket allocator to use
656  * @return The empty bucket brigade
657  */
659  apr_bucket_alloc_t *list);
660 
661 /**
662  * destroy an entire bucket brigade. This includes destroying all of the
663  * buckets within the bucket brigade's bucket list.
664  * @param b The bucket brigade to destroy
665  */
667 
668 /**
669  * empty out an entire bucket brigade. This includes destroying all of the
670  * buckets within the bucket brigade's bucket list. This is similar to
671  * apr_brigade_destroy(), except that it does not deregister the brigade's
672  * pool cleanup function.
673  * @param data The bucket brigade to clean up
674  * @remark Generally, you should use apr_brigade_destroy(). This function
675  * can be useful in situations where you have a single brigade that
676  * you wish to reuse many times by destroying all of the buckets in
677  * the brigade and putting new buckets into it later.
678  */
679 APU_DECLARE(apr_status_t) apr_brigade_cleanup(void *data);
680 
681 /**
682  * Move the buckets from the tail end of the existing brigade @a b into
683  * the brigade @a a. If @a a is NULL a new brigade is created. Buckets
684  * from @a e to the last bucket (inclusively) of brigade @a b are moved
685  * from @a b to the returned brigade @a a.
686  *
687  * @param b The brigade to split
688  * @param e The first bucket to move
689  * @param a The brigade which should be used for the result or NULL if
690  * a new brigade should be created.
691  * @return The brigade supplied in @param a or a new one if @param a was NULL.
692  * @warning Note that this function allocates a new brigade if @param a is
693  * NULL so memory consumption should be carefully considered.
694  */
696  apr_bucket *e,
697  apr_bucket_brigade *a);
698 
699 /**
700  * Create a new bucket brigade and move the buckets from the tail end
701  * of an existing brigade into the new brigade. Buckets from
702  * @param e to the last bucket (inclusively) of brigade @param b
703  * are moved from @param b to the returned brigade.
704  * @param b The brigade to split
705  * @param e The first bucket to move
706  * @return The new brigade
707  * @warning Note that this function always allocates a new brigade
708  * so memory consumption should be carefully considered.
709  */
711  apr_bucket *e);
712 
713 /**
714  * Partition a bucket brigade at a given offset (in bytes from the start of
715  * the brigade). This is useful whenever a filter wants to use known ranges
716  * of bytes from the brigade; the ranges can even overlap.
717  * @param b The brigade to partition
718  * @param point The offset at which to partition the brigade
719  * @param after_point Returns a pointer to the first bucket after the partition
720  * @return APR_SUCCESS on success, APR_INCOMPLETE if the contents of the
721  * brigade were shorter than @a point, or an error code.
722  * @remark if APR_INCOMPLETE is returned, @a after_point will be set to
723  * the brigade sentinel.
724  */
726  apr_off_t point,
727  apr_bucket **after_point);
728 
729 /**
730  * Return the total length of the brigade.
731  * @param bb The brigade to compute the length of
732  * @param read_all Read unknown-length buckets to force a size
733  * @param length Returns the length of the brigade (up to the end, or up
734  * to a bucket read error), or -1 if the brigade has buckets
735  * of indeterminate length and read_all is 0.
736  */
738  int read_all,
739  apr_off_t *length);
740 
741 /**
742  * Take a bucket brigade and store the data in a flat char*
743  * @param bb The bucket brigade to create the char* from
744  * @param c The char* to write into
745  * @param len The maximum length of the char array. On return, it is the
746  * actual length of the char array.
747  */
749  char *c,
750  apr_size_t *len);
751 
752 /**
753  * Creates a pool-allocated string representing a flat bucket brigade
754  * @param bb The bucket brigade to create the char array from
755  * @param c On return, the allocated char array
756  * @param len On return, the length of the char array.
757  * @param pool The pool to allocate the string from.
758  */
760  char **c,
761  apr_size_t *len,
762  apr_pool_t *pool);
763 
764 /**
765  * Split a brigade to represent one LF line.
766  * @param bbOut The bucket brigade that will have the LF line appended to.
767  * @param bbIn The input bucket brigade to search for a LF-line.
768  * @param block The blocking mode to be used to split the line.
769  * @param maxbytes The maximum bytes to read. If this many bytes are seen
770  * without a LF, the brigade will contain a partial line.
771  */
773  apr_bucket_brigade *bbIn,
774  apr_read_type_e block,
775  apr_off_t maxbytes);
776 
777 /**
778  * Create an iovec of the elements in a bucket_brigade... return number
779  * of elements used. This is useful for writing to a file or to the
780  * network efficiently.
781  * @param b The bucket brigade to create the iovec from
782  * @param vec The iovec to create
783  * @param nvec The number of elements in the iovec. On return, it is the
784  * number of iovec elements actually filled out.
785  */
787  struct iovec *vec, int *nvec);
788 
789 /**
790  * This function writes a list of strings into a bucket brigade.
791  * @param b The bucket brigade to add to
792  * @param flush The flush function to use if the brigade is full
793  * @param ctx The structure to pass to the flush function
794  * @param va A list of strings to add
795  * @return APR_SUCCESS or error code.
796  */
798  apr_brigade_flush flush,
799  void *ctx,
800  va_list va);
801 
802 /**
803  * This function writes a string into a bucket brigade.
804  *
805  * The apr_brigade_write function attempts to be efficient with the
806  * handling of heap buckets. Regardless of the amount of data stored
807  * inside a heap bucket, heap buckets are a fixed size to promote their
808  * reuse.
809  *
810  * If an attempt is made to write a string to a brigade that already
811  * ends with a heap bucket, this function will attempt to pack the
812  * string into the remaining space in the previous heap bucket, before
813  * allocating a new heap bucket.
814  *
815  * This function always returns APR_SUCCESS, unless a flush function is
816  * passed, in which case the return value of the flush function will be
817  * returned if used.
818  * @param b The bucket brigade to add to
819  * @param flush The flush function to use if the brigade is full
820  * @param ctx The structure to pass to the flush function
821  * @param str The string to add
822  * @param nbyte The number of bytes to write
823  * @return APR_SUCCESS or error code
824  */
826  apr_brigade_flush flush, void *ctx,
827  const char *str, apr_size_t nbyte);
828 
829 /**
830  * This function writes multiple strings into a bucket brigade.
831  * @param b The bucket brigade to add to
832  * @param flush The flush function to use if the brigade is full
833  * @param ctx The structure to pass to the flush function
834  * @param vec The strings to add (address plus length for each)
835  * @param nvec The number of entries in iovec
836  * @return APR_SUCCESS or error code
837  */
839  apr_brigade_flush flush,
840  void *ctx,
841  const struct iovec *vec,
842  apr_size_t nvec);
843 
844 /**
845  * This function writes a string into a bucket brigade.
846  * @param bb The bucket brigade to add to
847  * @param flush The flush function to use if the brigade is full
848  * @param ctx The structure to pass to the flush function
849  * @param str The string to add
850  * @return APR_SUCCESS or error code
851  */
853  apr_brigade_flush flush, void *ctx,
854  const char *str);
855 
856 /**
857  * This function writes a character into a bucket brigade.
858  * @param b The bucket brigade to add to
859  * @param flush The flush function to use if the brigade is full
860  * @param ctx The structure to pass to the flush function
861  * @param c The character to add
862  * @return APR_SUCCESS or error code
863  */
865  apr_brigade_flush flush, void *ctx,
866  const char c);
867 
868 /**
869  * This function writes an unspecified number of strings into a bucket brigade.
870  * @param b The bucket brigade to add to
871  * @param flush The flush function to use if the brigade is full
872  * @param ctx The structure to pass to the flush function
873  * @param ... The strings to add
874  * @return APR_SUCCESS or error code
875  */
877  apr_brigade_flush flush,
878  void *ctx, ...);
879 
880 /**
881  * Evaluate a printf and put the resulting string at the end
882  * of the bucket brigade.
883  * @param b The brigade to write to
884  * @param flush The flush function to use if the brigade is full
885  * @param ctx The structure to pass to the flush function
886  * @param fmt The format of the string to write
887  * @param ... The arguments to fill out the format
888  * @return APR_SUCCESS or error code
889  */
890 APU_DECLARE_NONSTD(apr_status_t) apr_brigade_printf(apr_bucket_brigade *b,
891  apr_brigade_flush flush,
892  void *ctx,
893  const char *fmt, ...)
894  __attribute__((format(printf,4,5)));
895 
896 /**
897  * Evaluate a printf and put the resulting string at the end
898  * of the bucket brigade.
899  * @param b The brigade to write to
900  * @param flush The flush function to use if the brigade is full
901  * @param ctx The structure to pass to the flush function
902  * @param fmt The format of the string to write
903  * @param va The arguments to fill out the format
904  * @return APR_SUCCESS or error code
905  */
907  apr_brigade_flush flush,
908  void *ctx,
909  const char *fmt, va_list va);
910 
911 /**
912  * Utility function to insert a file (or a segment of a file) onto the
913  * end of the brigade. The file is split into multiple buckets if it
914  * is larger than the maximum size which can be represented by a
915  * single bucket.
916  * @param bb the brigade to insert into
917  * @param f the file to insert
918  * @param start the offset of the start of the segment
919  * @param len the length of the segment of the file to insert
920  * @param p pool from which file buckets are allocated
921  * @return the last bucket inserted
922  */
924  apr_file_t *f,
925  apr_off_t start,
926  apr_off_t len,
927  apr_pool_t *p);
928 
929 
930 
931 /* ***** Bucket freelist functions ***** */
932 /**
933  * Create a bucket allocator.
934  * @param p This pool's underlying apr_allocator_t is used to allocate memory
935  * for the bucket allocator. When the pool is destroyed, the bucket
936  * allocator's cleanup routine will free all memory that has been
937  * allocated from it.
938  * @remark The reason the allocator gets its memory from the pool's
939  * apr_allocator_t rather than from the pool itself is because
940  * the bucket allocator will free large memory blocks back to the
941  * allocator when it's done with them, thereby preventing memory
942  * footprint growth that would occur if we allocated from the pool.
943  * @warning The allocator must never be used by more than one thread at a time.
944  */
945 APU_DECLARE_NONSTD(apr_bucket_alloc_t *) apr_bucket_alloc_create(apr_pool_t *p);
946 
947 /**
948  * Create a bucket allocator.
949  * @param allocator This apr_allocator_t is used to allocate both the bucket
950  * allocator and all memory handed out by the bucket allocator. The
951  * caller is responsible for destroying the bucket allocator and the
952  * apr_allocator_t -- no automatic cleanups will happen.
953  * @warning The allocator must never be used by more than one thread at a time.
954  */
955 APU_DECLARE_NONSTD(apr_bucket_alloc_t *) apr_bucket_alloc_create_ex(apr_allocator_t *allocator);
956 
957 /**
958  * Destroy a bucket allocator.
959  * @param list The allocator to be destroyed
960  */
961 APU_DECLARE_NONSTD(void) apr_bucket_alloc_destroy(apr_bucket_alloc_t *list);
962 
963 /**
964  * Allocate memory for use by the buckets.
965  * @param size The amount to allocate.
966  * @param list The allocator from which to allocate the memory.
967  */
968 APU_DECLARE_NONSTD(void *) apr_bucket_alloc(apr_size_t size, apr_bucket_alloc_t *list);
969 
970 /**
971  * Free memory previously allocated with apr_bucket_alloc().
972  * @param block The block of memory to be freed.
973  */
974 APU_DECLARE_NONSTD(void) apr_bucket_free(void *block);
975 
976 
977 /* ***** Bucket Functions ***** */
978 /**
979  * Free the resources used by a bucket. If multiple buckets refer to
980  * the same resource it is freed when the last one goes away.
981  * @see apr_bucket_delete()
982  * @param e The bucket to destroy
983  */
984 #define apr_bucket_destroy(e) do { \
985  (e)->type->destroy((e)->data); \
986  (e)->free(e); \
987  } while (0)
988 
989 /**
990  * Delete a bucket by removing it from its brigade (if any) and then
991  * destroying it.
992  * @remark This mainly acts as an aid in avoiding code verbosity. It is
993  * the preferred exact equivalent to:
994  * <pre>
995  * APR_BUCKET_REMOVE(e);
996  * apr_bucket_destroy(e);
997  * </pre>
998  * @param e The bucket to delete
999  */
1000 #define apr_bucket_delete(e) do { \
1001  APR_BUCKET_REMOVE(e); \
1002  apr_bucket_destroy(e); \
1003  } while (0)
1004 
1005 /**
1006  * Read some data from the bucket.
1007  *
1008  * The apr_bucket_read function returns a convenient amount of data
1009  * from the bucket provided, writing the address and length of the
1010  * data to the pointers provided by the caller. The function tries
1011  * as hard as possible to avoid a memory copy.
1012  *
1013  * Buckets are expected to be a member of a brigade at the time they
1014  * are read.
1015  *
1016  * In typical application code, buckets are read in a loop, and after
1017  * each bucket is read and processed, it is moved or deleted from the
1018  * brigade and the next bucket read.
1019  *
1020  * The definition of "convenient" depends on the type of bucket that
1021  * is being read, and is decided by APR. In the case of memory based
1022  * buckets such as heap and immortal buckets, a pointer will be
1023  * returned to the location of the buffer containing the complete
1024  * contents of the bucket.
1025  *
1026  * Some buckets, such as the socket bucket, might have no concept
1027  * of length. If an attempt is made to read such a bucket, the
1028  * apr_bucket_read function will read a convenient amount of data
1029  * from the socket. The socket bucket is magically morphed into a
1030  * heap bucket containing the just-read data, and a new socket bucket
1031  * is inserted just after this heap bucket.
1032  *
1033  * To understand why apr_bucket_read might do this, consider the loop
1034  * described above to read and process buckets. The current bucket
1035  * is magically morphed into a heap bucket and returned to the caller.
1036  * The caller processes the data, and deletes the heap bucket, moving
1037  * onto the next bucket, the new socket bucket. This process repeats,
1038  * giving the illusion of a bucket brigade that contains potentially
1039  * infinite amounts of data. It is up to the caller to decide at what
1040  * point to stop reading buckets.
1041  *
1042  * Some buckets, such as the file bucket, might have a fixed size,
1043  * but be significantly larger than is practical to store in RAM in
1044  * one go. As with the socket bucket, if an attempt is made to read
1045  * from a file bucket, the file bucket is magically morphed into a
1046  * heap bucket containing a convenient amount of data read from the
1047  * current offset in the file. During the read, the offset will be
1048  * moved forward on the file, and a new file bucket will be inserted
1049  * directly after the current bucket representing the remainder of the
1050  * file. If the heap bucket was large enough to store the whole
1051  * remainder of the file, no more file buckets are inserted, and the
1052  * file bucket will disappear completely.
1053  *
1054  * The pattern for reading buckets described above does create the
1055  * illusion that the code is willing to swallow buckets that might be
1056  * too large for the system to handle in one go. This however is just
1057  * an illusion: APR will always ensure that large (file) or infinite
1058  * (socket) buckets are broken into convenient bite sized heap buckets
1059  * before data is returned to the caller.
1060  *
1061  * There is a potential gotcha to watch for: if buckets are read in a
1062  * loop, and aren't deleted after being processed, the potentially large
1063  * bucket will slowly be converted into RAM resident heap buckets. If
1064  * the file is larger than available RAM, an out of memory condition
1065  * could be caused if the application is not careful to manage this.
1066  *
1067  * @param e The bucket to read from
1068  * @param str The location to store a pointer to the data in
1069  * @param len The location to store the amount of data read
1070  * @param block Whether the read function blocks
1071  */
1072 #define apr_bucket_read(e,str,len,block) (e)->type->read(e, str, len, block)
1073 
1074 /**
1075  * Setaside data so that stack data is not destroyed on returning from
1076  * the function
1077  * @param e The bucket to setaside
1078  * @param p The pool to setaside into
1079  */
1080 #define apr_bucket_setaside(e,p) (e)->type->setaside(e,p)
1081 
1082 /**
1083  * Split one bucket in two at the point provided.
1084  *
1085  * Once split, the original bucket becomes the first of the two new buckets.
1086  *
1087  * (It is assumed that the bucket is a member of a brigade when this
1088  * function is called).
1089  * @param e The bucket to split
1090  * @param point The offset to split the bucket at
1091  */
1092 #define apr_bucket_split(e,point) (e)->type->split(e, point)
1093 
1094 /**
1095  * Copy a bucket.
1096  * @param e The bucket to copy
1097  * @param c Returns a pointer to the new bucket
1098  */
1099 #define apr_bucket_copy(e,c) (e)->type->copy(e, c)
1100 
1101 /* Bucket type handling */
1102 
1103 /**
1104  * This function simply returns APR_SUCCESS to denote that the bucket does
1105  * not require anything to happen for its setaside() function. This is
1106  * appropriate for buckets that have "immortal" data -- the data will live
1107  * at least as long as the bucket.
1108  * @param data The bucket to setaside
1109  * @param pool The pool defining the desired lifetime of the bucket data
1110  * @return APR_SUCCESS
1111  */
1112 APU_DECLARE_NONSTD(apr_status_t) apr_bucket_setaside_noop(apr_bucket *data,
1113  apr_pool_t *pool);
1114 
1115 /**
1116  * A place holder function that signifies that the setaside function was not
1117  * implemented for this bucket
1118  * @param data The bucket to setaside
1119  * @param pool The pool defining the desired lifetime of the bucket data
1120  * @return APR_ENOTIMPL
1121  */
1122 APU_DECLARE_NONSTD(apr_status_t) apr_bucket_setaside_notimpl(apr_bucket *data,
1123  apr_pool_t *pool);
1124 
1125 /**
1126  * A place holder function that signifies that the split function was not
1127  * implemented for this bucket
1128  * @param data The bucket to split
1129  * @param point The location to split the bucket
1130  * @return APR_ENOTIMPL
1131  */
1132 APU_DECLARE_NONSTD(apr_status_t) apr_bucket_split_notimpl(apr_bucket *data,
1133  apr_size_t point);
1134 
1135 /**
1136  * A place holder function that signifies that the copy function was not
1137  * implemented for this bucket
1138  * @param e The bucket to copy
1139  * @param c Returns a pointer to the new bucket
1140  * @return APR_ENOTIMPL
1141  */
1142 APU_DECLARE_NONSTD(apr_status_t) apr_bucket_copy_notimpl(apr_bucket *e,
1143  apr_bucket **c);
1144 
1145 /**
1146  * A place holder function that signifies that this bucket does not need
1147  * to do anything special to be destroyed. That's only the case for buckets
1148  * that either have no data (metadata buckets) or buckets whose data pointer
1149  * points to something that's not a bucket-type-specific structure, as with
1150  * simple buckets where data points to a string and pipe buckets where data
1151  * points directly to the apr_file_t.
1152  * @param data The bucket data to destroy
1153  */
1154 APU_DECLARE_NONSTD(void) apr_bucket_destroy_noop(void *data);
1155 
1156 /**
1157  * There is no apr_bucket_destroy_notimpl, because destruction is required
1158  * to be implemented (it could be a noop, but only if that makes sense for
1159  * the bucket type)
1160  */
1161 
1162 /* There is no apr_bucket_read_notimpl, because it is a required function
1163  */
1164 
1165 
1166 /* All of the bucket types implemented by the core */
1167 /**
1168  * The flush bucket type. This signifies that all data should be flushed to
1169  * the next filter. The flush bucket should be sent with the other buckets.
1170  */
1171 APU_DECLARE_DATA extern const apr_bucket_type_t apr_bucket_type_flush;
1172 /**
1173  * The EOS bucket type. This signifies that there will be no more data, ever.
1174  * All filters MUST send all data to the next filter when they receive a
1175  * bucket of this type
1176  */
1177 APU_DECLARE_DATA extern const apr_bucket_type_t apr_bucket_type_eos;
1178 /**
1179  * The FILE bucket type. This bucket represents a file on disk
1180  */
1181 APU_DECLARE_DATA extern const apr_bucket_type_t apr_bucket_type_file;
1182 /**
1183  * The HEAP bucket type. This bucket represents a data allocated from the
1184  * heap.
1185  */
1186 APU_DECLARE_DATA extern const apr_bucket_type_t apr_bucket_type_heap;
1187 #if APR_HAS_MMAP
1188 /**
1189  * The MMAP bucket type. This bucket represents an MMAP'ed file
1190  */
1191 APU_DECLARE_DATA extern const apr_bucket_type_t apr_bucket_type_mmap;
1192 #endif
1193 /**
1194  * The POOL bucket type. This bucket represents a data that was allocated
1195  * from a pool. IF this bucket is still available when the pool is cleared,
1196  * the data is copied on to the heap.
1197  */
1198 APU_DECLARE_DATA extern const apr_bucket_type_t apr_bucket_type_pool;
1199 /**
1200  * The PIPE bucket type. This bucket represents a pipe to another program.
1201  */
1202 APU_DECLARE_DATA extern const apr_bucket_type_t apr_bucket_type_pipe;
1203 /**
1204  * The IMMORTAL bucket type. This bucket represents a segment of data that
1205  * the creator is willing to take responsibility for. The core will do
1206  * nothing with the data in an immortal bucket
1207  */
1208 APU_DECLARE_DATA extern const apr_bucket_type_t apr_bucket_type_immortal;
1209 /**
1210  * The TRANSIENT bucket type. This bucket represents a data allocated off
1211  * the stack. When the setaside function is called, this data is copied on
1212  * to the heap
1213  */
1214 APU_DECLARE_DATA extern const apr_bucket_type_t apr_bucket_type_transient;
1215 /**
1216  * The SOCKET bucket type. This bucket represents a socket to another machine
1217  */
1218 APU_DECLARE_DATA extern const apr_bucket_type_t apr_bucket_type_socket;
1219 
1220 
1221 /* ***** Simple buckets ***** */
1222 
1223 /**
1224  * Split a simple bucket into two at the given point. Most non-reference
1225  * counting buckets that allow multiple references to the same block of
1226  * data (eg transient and immortal) will use this as their split function
1227  * without any additional type-specific handling.
1228  * @param b The bucket to be split
1229  * @param point The offset of the first byte in the new bucket
1230  * @return APR_EINVAL if the point is not within the bucket;
1231  * APR_ENOMEM if allocation failed;
1232  * or APR_SUCCESS
1233  */
1234 APU_DECLARE_NONSTD(apr_status_t) apr_bucket_simple_split(apr_bucket *b,
1235  apr_size_t point);
1236 
1237 /**
1238  * Copy a simple bucket. Most non-reference-counting buckets that allow
1239  * multiple references to the same block of data (eg transient and immortal)
1240  * will use this as their copy function without any additional type-specific
1241  * handling.
1242  * @param a The bucket to copy
1243  * @param b Returns a pointer to the new bucket
1244  * @return APR_ENOMEM if allocation failed;
1245  * or APR_SUCCESS
1246  */
1247 APU_DECLARE_NONSTD(apr_status_t) apr_bucket_simple_copy(apr_bucket *a,
1248  apr_bucket **b);
1249 
1250 
1251 /* ***** Shared, reference-counted buckets ***** */
1252 
1253 /**
1254  * Initialize a bucket containing reference-counted data that may be
1255  * shared. The caller must allocate the bucket if necessary and
1256  * initialize its type-dependent fields, and allocate and initialize
1257  * its own private data structure. This function should only be called
1258  * by type-specific bucket creation functions.
1259  * @param b The bucket to initialize
1260  * @param data A pointer to the private data structure
1261  * with the reference count at the start
1262  * @param start The start of the data in the bucket
1263  * relative to the private base pointer
1264  * @param length The length of the data in the bucket
1265  * @return The new bucket, or NULL if allocation failed
1266  */
1267 APU_DECLARE(apr_bucket *) apr_bucket_shared_make(apr_bucket *b, void *data,
1268  apr_off_t start,
1269  apr_size_t length);
1270 
1271 /**
1272  * Decrement the refcount of the data in the bucket. This function
1273  * should only be called by type-specific bucket destruction functions.
1274  * @param data The private data pointer from the bucket to be destroyed
1275  * @return TRUE or FALSE; TRUE if the reference count is now
1276  * zero, indicating that the shared resource itself can
1277  * be destroyed by the caller.
1278  */
1279 APU_DECLARE(int) apr_bucket_shared_destroy(void *data);
1280 
1281 /**
1282  * Split a bucket into two at the given point, and adjust the refcount
1283  * to the underlying data. Most reference-counting bucket types will
1284  * be able to use this function as their split function without any
1285  * additional type-specific handling.
1286  * @param b The bucket to be split
1287  * @param point The offset of the first byte in the new bucket
1288  * @return APR_EINVAL if the point is not within the bucket;
1289  * APR_ENOMEM if allocation failed;
1290  * or APR_SUCCESS
1291  */
1292 APU_DECLARE_NONSTD(apr_status_t) apr_bucket_shared_split(apr_bucket *b,
1293  apr_size_t point);
1294 
1295 /**
1296  * Copy a refcounted bucket, incrementing the reference count. Most
1297  * reference-counting bucket types will be able to use this function
1298  * as their copy function without any additional type-specific handling.
1299  * @param a The bucket to copy
1300  * @param b Returns a pointer to the new bucket
1301  * @return APR_ENOMEM if allocation failed;
1302  or APR_SUCCESS
1303  */
1304 APU_DECLARE_NONSTD(apr_status_t) apr_bucket_shared_copy(apr_bucket *a,
1305  apr_bucket **b);
1306 
1307 
1308 /* ***** Functions to Create Buckets of varying types ***** */
1309 /*
1310  * Each bucket type foo has two initialization functions:
1311  * apr_bucket_foo_make which sets up some already-allocated memory as a
1312  * bucket of type foo; and apr_bucket_foo_create which allocates memory
1313  * for the bucket, calls apr_bucket_make_foo, and initializes the
1314  * bucket's list pointers. The apr_bucket_foo_make functions are used
1315  * inside the bucket code to change the type of buckets in place;
1316  * other code should call apr_bucket_foo_create. All the initialization
1317  * functions change nothing if they fail.
1318  */
1319 
1320 /**
1321  * Create an End of Stream bucket. This indicates that there is no more data
1322  * coming from down the filter stack. All filters should flush at this point.
1323  * @param list The freelist from which this bucket should be allocated
1324  * @return The new bucket, or NULL if allocation failed
1325  */
1327 
1328 /**
1329  * Make the bucket passed in an EOS bucket. This indicates that there is no
1330  * more data coming from down the filter stack. All filters should flush at
1331  * this point.
1332  * @param b The bucket to make into an EOS bucket
1333  * @return The new bucket, or NULL if allocation failed
1334  */
1335 APU_DECLARE(apr_bucket *) apr_bucket_eos_make(apr_bucket *b);
1336 
1337 /**
1338  * Create a flush bucket. This indicates that filters should flush their
1339  * data. There is no guarantee that they will flush it, but this is the
1340  * best we can do.
1341  * @param list The freelist from which this bucket should be allocated
1342  * @return The new bucket, or NULL if allocation failed
1343  */
1345 
1346 /**
1347  * Make the bucket passed in a FLUSH bucket. This indicates that filters
1348  * should flush their data. There is no guarantee that they will flush it,
1349  * but this is the best we can do.
1350  * @param b The bucket to make into a FLUSH bucket
1351  * @return The new bucket, or NULL if allocation failed
1352  */
1353 APU_DECLARE(apr_bucket *) apr_bucket_flush_make(apr_bucket *b);
1354 
1355 /**
1356  * Create a bucket referring to long-lived data.
1357  * @param buf The data to insert into the bucket
1358  * @param nbyte The size of the data to insert.
1359  * @param list The freelist from which this bucket should be allocated
1360  * @return The new bucket, or NULL if allocation failed
1361  */
1362 APU_DECLARE(apr_bucket *) apr_bucket_immortal_create(const char *buf,
1363  apr_size_t nbyte,
1364  apr_bucket_alloc_t *list);
1365 
1366 /**
1367  * Make the bucket passed in a bucket refer to long-lived data
1368  * @param b The bucket to make into a IMMORTAL bucket
1369  * @param buf The data to insert into the bucket
1370  * @param nbyte The size of the data to insert.
1371  * @return The new bucket, or NULL if allocation failed
1372  */
1374  const char *buf,
1375  apr_size_t nbyte);
1376 
1377 /**
1378  * Create a bucket referring to data on the stack.
1379  * @param buf The data to insert into the bucket
1380  * @param nbyte The size of the data to insert.
1381  * @param list The freelist from which this bucket should be allocated
1382  * @return The new bucket, or NULL if allocation failed
1383  */
1384 APU_DECLARE(apr_bucket *) apr_bucket_transient_create(const char *buf,
1385  apr_size_t nbyte,
1386  apr_bucket_alloc_t *list);
1387 
1388 /**
1389  * Make the bucket passed in a bucket refer to stack data
1390  * @param b The bucket to make into a TRANSIENT bucket
1391  * @param buf The data to insert into the bucket
1392  * @param nbyte The size of the data to insert.
1393  * @return The new bucket, or NULL if allocation failed
1394  */
1396  const char *buf,
1397  apr_size_t nbyte);
1398 
1399 /**
1400  * Create a bucket referring to memory on the heap. If the caller asks
1401  * for the data to be copied, this function always allocates 4K of
1402  * memory so that more data can be added to the bucket without
1403  * requiring another allocation. Therefore not all the data may be put
1404  * into the bucket. If copying is not requested then the bucket takes
1405  * over responsibility for free()ing the memory.
1406  * @param buf The buffer to insert into the bucket
1407  * @param nbyte The size of the buffer to insert.
1408  * @param free_func Function to use to free the data; NULL indicates that the
1409  * bucket should make a copy of the data
1410  * @param list The freelist from which this bucket should be allocated
1411  * @return The new bucket, or NULL if allocation failed
1412  */
1413 APU_DECLARE(apr_bucket *) apr_bucket_heap_create(const char *buf,
1414  apr_size_t nbyte,
1415  void (*free_func)(void *data),
1416  apr_bucket_alloc_t *list);
1417 /**
1418  * Make the bucket passed in a bucket refer to heap data
1419  * @param b The bucket to make into a HEAP bucket
1420  * @param buf The buffer to insert into the bucket
1421  * @param nbyte The size of the buffer to insert.
1422  * @param free_func Function to use to free the data; NULL indicates that the
1423  * bucket should make a copy of the data
1424  * @return The new bucket, or NULL if allocation failed
1425  */
1426 APU_DECLARE(apr_bucket *) apr_bucket_heap_make(apr_bucket *b, const char *buf,
1427  apr_size_t nbyte,
1428  void (*free_func)(void *data));
1429 
1430 /**
1431  * Create a bucket referring to memory allocated from a pool.
1432  *
1433  * @param buf The buffer to insert into the bucket
1434  * @param length The number of bytes referred to by this bucket
1435  * @param pool The pool the memory was allocated from
1436  * @param list The freelist from which this bucket should be allocated
1437  * @return The new bucket, or NULL if allocation failed
1438  */
1439 APU_DECLARE(apr_bucket *) apr_bucket_pool_create(const char *buf,
1440  apr_size_t length,
1441  apr_pool_t *pool,
1442  apr_bucket_alloc_t *list);
1443 
1444 /**
1445  * Make the bucket passed in a bucket refer to pool data
1446  * @param b The bucket to make into a pool bucket
1447  * @param buf The buffer to insert into the bucket
1448  * @param length The number of bytes referred to by this bucket
1449  * @param pool The pool the memory was allocated from
1450  * @return The new bucket, or NULL if allocation failed
1451  */
1452 APU_DECLARE(apr_bucket *) apr_bucket_pool_make(apr_bucket *b, const char *buf,
1453  apr_size_t length,
1454  apr_pool_t *pool);
1455 
1456 #if APR_HAS_MMAP
1457 /**
1458  * Create a bucket referring to mmap()ed memory.
1459  * @param mm The mmap to insert into the bucket
1460  * @param start The offset of the first byte in the mmap
1461  * that this bucket refers to
1462  * @param length The number of bytes referred to by this bucket
1463  * @param list The freelist from which this bucket should be allocated
1464  * @return The new bucket, or NULL if allocation failed
1465  */
1466 APU_DECLARE(apr_bucket *) apr_bucket_mmap_create(apr_mmap_t *mm,
1467  apr_off_t start,
1468  apr_size_t length,
1469  apr_bucket_alloc_t *list);
1470 
1471 /**
1472  * Make the bucket passed in a bucket refer to an MMAP'ed file
1473  * @param b The bucket to make into a MMAP bucket
1474  * @param mm The mmap to insert into the bucket
1475  * @param start The offset of the first byte in the mmap
1476  * that this bucket refers to
1477  * @param length The number of bytes referred to by this bucket
1478  * @return The new bucket, or NULL if allocation failed
1479  */
1480 APU_DECLARE(apr_bucket *) apr_bucket_mmap_make(apr_bucket *b, apr_mmap_t *mm,
1481  apr_off_t start,
1482  apr_size_t length);
1483 #endif
1484 
1485 /**
1486  * Create a bucket referring to a socket.
1487  * @param thissock The socket to put in the bucket
1488  * @param list The freelist from which this bucket should be allocated
1489  * @return The new bucket, or NULL if allocation failed
1490  */
1491 APU_DECLARE(apr_bucket *) apr_bucket_socket_create(apr_socket_t *thissock,
1492  apr_bucket_alloc_t *list);
1493 /**
1494  * Make the bucket passed in a bucket refer to a socket
1495  * @param b The bucket to make into a SOCKET bucket
1496  * @param thissock The socket to put in the bucket
1497  * @return The new bucket, or NULL if allocation failed
1498  */
1499 APU_DECLARE(apr_bucket *) apr_bucket_socket_make(apr_bucket *b,
1500  apr_socket_t *thissock);
1501 
1502 /**
1503  * Create a bucket referring to a pipe.
1504  * @param thispipe The pipe to put in the bucket
1505  * @param list The freelist from which this bucket should be allocated
1506  * @return The new bucket, or NULL if allocation failed
1507  */
1508 APU_DECLARE(apr_bucket *) apr_bucket_pipe_create(apr_file_t *thispipe,
1509  apr_bucket_alloc_t *list);
1510 
1511 /**
1512  * Make the bucket passed in a bucket refer to a pipe
1513  * @param b The bucket to make into a PIPE bucket
1514  * @param thispipe The pipe to put in the bucket
1515  * @return The new bucket, or NULL if allocation failed
1516  */
1517 APU_DECLARE(apr_bucket *) apr_bucket_pipe_make(apr_bucket *b,
1518  apr_file_t *thispipe);
1519 
1520 /**
1521  * Create a bucket referring to a file.
1522  * @param fd The file to put in the bucket
1523  * @param offset The offset where the data of interest begins in the file
1524  * @param len The amount of data in the file we are interested in
1525  * @param p The pool into which any needed structures should be created
1526  * while reading from this file bucket
1527  * @param list The freelist from which this bucket should be allocated
1528  * @return The new bucket, or NULL if allocation failed
1529  * @remark If the file is truncated such that the segment of the file
1530  * referenced by the bucket no longer exists, an attempt to read
1531  * from the bucket will fail with APR_EOF.
1532  * @remark apr_brigade_insert_file() should generally be used to
1533  * insert files into brigades, since that function can correctly
1534  * handle large file issues.
1535  */
1536 APU_DECLARE(apr_bucket *) apr_bucket_file_create(apr_file_t *fd,
1537  apr_off_t offset,
1538  apr_size_t len,
1539  apr_pool_t *p,
1540  apr_bucket_alloc_t *list);
1541 
1542 /**
1543  * Make the bucket passed in a bucket refer to a file
1544  * @param b The bucket to make into a FILE bucket
1545  * @param fd The file to put in the bucket
1546  * @param offset The offset where the data of interest begins in the file
1547  * @param len The amount of data in the file we are interested in
1548  * @param p The pool into which any needed structures should be created
1549  * while reading from this file bucket
1550  * @return The new bucket, or NULL if allocation failed
1551  */
1552 APU_DECLARE(apr_bucket *) apr_bucket_file_make(apr_bucket *b, apr_file_t *fd,
1553  apr_off_t offset,
1554  apr_size_t len, apr_pool_t *p);
1555 
1556 /**
1557  * Enable or disable memory-mapping for a FILE bucket (default is enabled)
1558  * @param b The bucket
1559  * @param enabled Whether memory-mapping should be enabled
1560  * @return APR_SUCCESS normally, or an error code if the operation fails
1561  */
1563  int enabled);
1564 
1565 /** @} */
1566 #ifdef __cplusplus
1567 }
1568 #endif
1569 
1570 #endif /* !APR_BUCKETS_H */